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System 824 Reference Manual

1. a 3 21 Taktmaximal terri ete lace OU 2 4 6 2 Pemplate Settings reete pre det dei eere T EE A 36 THD Measurement FET Instrumen ERR 12 9 Tilde Symbol oo ep E a e de ad ie i t qe 4 14 Time allowed Exposure time Ti sese eene nnne enne nen D 1 OnD OME tice ee ege iR ri e cet or eel ah e Pri es epe 13 23 NITIDIS D 23 TameEHstOryvz e o dr PER NOU SENE RR Stet eut I I ERE 6 7 Check onere e ier aene iced Ede 7 16 Displays sees a SOS ERR ede o e EN hie en TRIES 5 13 Exceedance ead aid 5 55 Maxvs Peak level ok ERR eR e Re IM G 7 9 Display zc s trs RR hi Ao tvs hone see cates a E end 5 16 VIC WS oe s xd RI OU t 5 42 AIMCO EY 3 23 Timer MOGs erre ete eA ed eh Se eR RAS 3 25 un PEN 3 16 Tatle Seting eme ott eat ute et b t aene eh RR C 7 5 Tools Keys e e M Nei de Nu 3 18 Transducet ze tede iN UR Rana e ee 12 5 Transducetr Setting oeste deri pertes vete ste desee ete da 7 8 Triggering Hysteresis RH SE ERR RE EORR e 7 24 Peak Exed DVI RR RR Ue EU EET 7 24 Peak Excd by125 s ote ee edt etim Ded 7 24 SPE Excd Evl 1 sii Rt ee CU ees tet etie ate eh AS 7 23 SPE EXcd
2. Nominal Exact Flat Weight C Weight Freq Freq 10 10 00 0 0 72 6 14 5 12 5 12 59 0 0 65 5 11 4 16 15 85 0 0 58 8 8 6 20 19 95 0 0 52 5 6 3 25 25 12 0 0 46 8 4 5 31 5 31 62 0 0 41 5 3 1 40 39 81 0 0 36 6 2 1 50 50 12 0 0 32 2 1 4 63 63 10 0 0 28 2 0 9 80 79 43 0 0 24 5 0 6 100 100 00 0 0 21 1 0 4 125 125 00 0 0 18 1 0 2 160 158 50 0 0 15 3 0 1 200 199 50 0 0 12 8 0 1 250 251 20 0 0 10 6 0 1 315 316 20 0 0 8 6 0 0 400 398 10 0 0 6 7 0 0 500 501 20 0 0 5 2 0 0 630 631 00 0 0 3 8 0 0 800 794 30 0 0 2 8 0 0 1000 1000 00 0 0 1 9 0 0 1250 1259 00 0 0 1 3 0 0 1600 1585 00 0 0 0 9 0 0 2000 1995 00 0 0 0 6 0 0 2500 2512 00 0 0 0 4 0 0 3150 3162 00 0 0 0 2 0 0 4000 3981 00 0 0 0 2 0 0 5000 5012 00 0 0 0 1 0 0 6300 6310 00 0 0 0 1 0 0 8000 7943 00 0 0 0 0 0 0 10000 10000 00 0 0 0 0 0 0 12500 12590 00 0 0 0 0 0 0 16000 15850 00 0 0 0 0 0 0 20000 19950 00 0 0 0 0 0 0 RTA Mode Specifications Filter types Flat Aor C preweighted 1 3 or 1 1 octave filters with broadband SPL Averaging Exponential 1 32 1 16 1 8 1 4 1 2 1 2 4 8 16 32 64 seconds Linear 0 0025 to 99 995 seconds Overall time gt 1 year Linearity range gt 80 dB 1 3 octave gt 75 dB 1 1 octave Reference level range 0 dB gain Sample rate 51 200 Hz 1 3 octave band frequencies 12 5 Hz 20 kHz 33 filters
3. A 7 33 eo esie ed 7 33 Umts T 7 33 R solution nete eiae edu dta ect bee PERDE 7 34 I ACIE 3 16 ID Setting Files Advanced Menu eroe utis eed ipe ra de Rer 7 56 Bandwidth Setting idit e eee REO M ed 7 10 Commons DEM Settings nct IO Rd et DR qi 7 5 TI EE 7 2 Customizing example evertere decere tutte NN IN ee Teens 7 2 Customizing Set ngs ree recepte ire etre perte ues 7 2 Detector Settings st euet e RUE 7 5 Gam Setting orit ero tete estu eru pu hus 7 6 ISM Menu Layout bre dee ipe eee A nup 7 50 POGvand SSA Intervals et uen et 7 36 LOG and SSA En tret ee Bate n e e te E Db re 7 20 LOG and SSA Time History 2 2 122000 00400000600000000000000000000000000000000 7 30 Logging SEM Define Report ete eet editt o PEE TA 7 42 Logging SLM 2 1 2 1 00 00000000000000000000000000000000000000000000 7 40 Logging SEM Menu Layout tse RE seed 7 52 Logging aede be 7 17 Peak sos Score i I E RI gets 7 9 Random Incidence Microphone sese enne enne nennen 7 8 Range Setting i res RE
4. Submenu Available Settings Options Available Settings Options Now L Arm Mode L gt Input Time Count Arm Arm Level 0 0 255 9 dB Arm Time 00 0000 to 99 9975 sec Arm Samples 0 65535 Arm Logic In High Now L Trigger Mode L gt Input Time Count Trigger Trigger Level 0 0 255 9 dB Trigger Time 00 0000 to 99 9975 sec Trig Samples 0 65535 Low Trig Logic In High Never L End mode L gt Input Time Count End End Level 0 0 255 9dB End Time 00 0000 to 99 9975 sec End Samples 0 65535 3 Low End Logic In High Stop End Then Repeat Average Then Repeat Count 0 255 Average Count 0 9 Run on Input No Yes optional Trigger Setup continued Run Logic In Menu Items Submenu Available Settings Options Available Settings Options Low High Logic Out e 65535 RT60 dB Down 5 10 15 20 25 30 Auto RT60 No Yes Note 8 Characters Settings Descriptions RTA Settings Menu 11 6 Title Setting Use the title setting to create a title or heading for printed reports This title will be placed at the top of each RTA report you print Gain Setting Gain adjusts the voltage level delivered to the measuring portion of the meter from the microphone and preamplifier Bandwidth Setting Selects 1 1 or 1 3 octave filter bandwidth for real time analysis Detector Setting Selec
5. 556 RTA RTAf EXPONENTIAL DETECTOR 1 64 1 32 1 16 1 8 1 4 TIME 1 2 1 2 4 8 16 32 64 SECONDS 557 LOG OVERALL THRESHOLD S57 RTA RTAf EXPONENTIAL DETECTOR 1 2 1 8 SECONDS STORAGE RATE S58 LOG OVERALL CRITERION S58 RTA RTAf RTAf AUTOMATIC RESET AT NO YES TRIGGER 59 LOG CRITERION TIME HOURS S59 RTA RTAf AUTOMATICALLY STORE YES NO EVENT RECORDS S60 LOG LDL EXCHANGE RATE S60 RTA RTAf ENABLE EVENT BYTIME NO YES HISTORY S61 LOG LDL THRESHOLD S61 RTA RTAf EVENT BYTIME PRETRIG NNN GER SAMPLES S62 LOG LDL CRITERION S62 RTA RTAf EVENT TRIGGERING NO YES ENABLE S63 LOG Lnn 1 PERCENT S63 RTA RTAf TRIGGER SOURCE LEVEL 12 5 16 0 16 0K 20 0K FLAT Hz S64 LOG Lnn 2 PERCENT S64 RTA RTAf ARM MODE NOW L lt L L gt INPUT TIME COUNT S65 LOG Lnn 3 PERCENT S65 RTA RTAf ARM LEVEL NNN N dB A 40 824 Reference Manual 9 29 09 TRUE LEVEL S66 LOG Lnn 4 PERCENT S66 RTA RTAf ARM TIME SS SSSS SECONDS FOR LEVEL AND TIME ARM MODE CONDI TIONS S67 LOG Lnn 5 PERCENT S67 RTA RTAf ARM SAMPLES NNNN S68 LOG Lnn 6 PERCENT S68 RTA RTAf ARM LOGIC INPUT TRUE LOW HIGH LEVEL S69 SSA ISM SPL Exceedance Level 1 LOG S69 RTA RTAf TRIGGER MODE NOW L lt L L gt INPUT TIME COUNT 570 SSA ISM SPL Exceedance Level 2 LOG S70 RTA RTAf TRIGGER LEVEL NNN N dB S71 SSA ISM Peak II
6. Menu Items Purpose Mark Puts a marker in the time history record Locate Allows you to locate a time history record Settings Modifies the Time History Settings Graph Adjusts the scaling of the Time History graph Intervals Check Menu The Intervals view has access to the following Check menu Intervals Eeginingois Ending Find gt Settings gt Menu Items Purpose Locate Locates an interval record Settings Modifies the Interval Settings 7 76 824 Reference Manual 9 29 09 Excd History Check Menu The Excd History displays have two different check menus depending upon which display you are viewing When viewing the displays Excd a through Excd b the following menu appears after pressing the Check Y key View Excd Time History Ert Il Settings gt Following is a chart of the check menu with a description of each menu item Menu Items Purpose Time History Displays the Excd time history graph Locate Locates a specific Exceedance record Settings Modifies the Exceedance settings In the Excd Time History display press the Check key and the following menu appears Excd Locate gt Settings gt Graph 9 29 09 Using ID Setting Files 7 77 Daily History Check Menu 7 78 Following is a chart of the Excd Time History check menu with a desc
7. Hec e HR nte onte em e e de ne 11 39 gy 7 66 Then Settings Men e eR ee Ue epe tete se eed 11 14 Eeveldae uie edu uto hemos R 11 10 Arm Logic In sce RR RE RE EEG IRR IE 11 10 tate e et d tertie dpa to ui etes e Pe Mp 11 9 Aim samples eR eoi e ee ERI RR p tee 11 10 1v xvi Index Model 831 Technical Reference Manual Arm Settings Menu RHET UREEREE 11 9 OUO NI ie m En RN ead 11 10 Auto RTO ano or Pe Mh de eae eee a eee 11 16 Autostore 3 oen to e e ean poa regente esee tre toas Sou Pence SON Tbe 11 8 Autostore Settings e de pe e rie ete ie 11 8 Autostore VIC WS vcnit hie ates named eati od 11 25 Average History Check 11 38 Average Count icu eee PE TERI Ev tre ene RON a 11 14 Avg History Check Men ies RH t Eri Reese err RH eda 11 38 Bandwidth Setting inei Cere TREE ere e ees tes 11 6 By Time Graph Check Menu e ete tie eet edet raise eet eat 11 31 ByTime Spectral History e ere eie e e He eee a eee 11 29 ByTime Spectrum Check Menu eese enne enn 11 30 Check enne E e ERE e NER 11 35 Detector Setting carea r ott te SE EEE E ee
8. e puce diee eae 8 8 tailored report Rn ee tee re eti hi de 8 5 Pulse Tone Definitions Fall Time a2 eee d E cent eee ee ees eh ee de dms 13 22 13 23 On cce RERO UE ar rer 13 23 uum sre uen nofi 13 22 And 13 23 Pulse Trigger Voltage Setup ade e rero PORRO ie ee eee ede eei 7 30 Pulse Widths itm tes 13 23 Q Querying Settings ettet ge te deett eie de du ai etd 31 R Random Incidence CoIrection rete 7 8 1v xiv Index Model 831 Technical Reference Manual Read Commands EET Te 10 rir EE 2 13 Formatted Reports eae dese etse n bete tede i 8 8 ID Setting Files three Rr a ehe etin 7 1 stored data ML tb d a tup LIED E 4 11 Reference Leye Range uso tete UE Ote e et ie ee eo Eee tr d ut F 1 Point microphone ele e ei ret e ER F 1 Sound Pressure Level oi EP EPOR Des dienten F 1 Remote Commands Setting Commands sd Eee eee e qe Egit ien A 30 Remote Control Any Data Read Commands e ete P ee e e d een A 25 Addressing Commands EE REE e ite e EN een 6 Advance Records ie oeste Eo E UD UD PEDE IR IUe E
9. 5 43 Overall CTITIO Rt oh n viet a cd as ee Te pace a a a a ea e eco ed oet 7 18 Criterion Level setting edi qe 7 18 Exchange aso am DERE DEUDA ER 7 17 SLM Vile CH EET 5 25 Threshold ER RAO Be dn Ri eet 7 18 OVETShO0t sic eat d a Not e d d es 13 23 P Parameter character strings seed tpe RU BOR aret Boos heel E E RET A 30 imdexed eR EUER UTR C ROSEO A 30 intu ETC A 30 E 30 templates sce stem e eae eee egeo tete nte hebes ae dta eaters A 30 teet tee ce eee ee eee o rete 5 67 Pause T nction 11 2 dee ore bn IR ne eniti e ee o d ge eel et 2 8 ee ehsbeeet 3 10 IDeasurement i ced 2 8 Performing a e RR Re tati ede ipe pps 2 7 Periodic Testing A Weighted Levels SR RS S eU BIS F 4 Permanent IDs cet dete e eee Caves E e DTE UA TERRA ete iris eer REIR 4 15 Power AC Adaptor cce eget te it ee ee te e dett ete 1 20 Bale ny svete S 1 18 CONSEL VATION 2 er UR eel seks elena EE e To ee 3 8 Model 831 Technical Reference Manual Index iv xiii Display i 4 ern i E va Eve ee edat aan 3 4 display inre teo rein ren e et 3 4 External 42 nv eon IU RERO eon ce RERO die 1 20 External Pow
10. Residual RT 60 Hz o 99 099 NS 9 Aq 3 amp o o9 999 11 2 824 Reference Manual 9 29 09 9 29 09 For other information pertaining to the RTA instrument see the following in this manual For data storage see Taking Measurements and Storing Data on page 4 5 For printing RTA reports see Printing Reports on page 8 2 For I O commands see Serial Port Interface Remote Control on page A 1 For specifications see RTA Mode Specifications on page C 18 optional 11 3 The menu layout of the RTA settings is shown in the table below Menu Items Title Submenu Available Settings Options User customized text entry Available Settings Options RTA Gain dB 20 10 0 10 20 30 40 50 Bandwidth 11 1 3 Detector Lin Exp Lin Detc Time 0 0025 to 99 9975 sec Exp Detc Time seconds 1 32 1 16 1 8 1 4 1 2 1 2 4 8 16 32 64 Exp Store Rate 1 2 second 1 8 second Transducer Condnsr Electret Direct Random Corr No Yes Autostore Autostore No Yes Pretrigger 0 400 samples Save ByTime No Yes Trigger Setup Triggering No Yes Trigger Source Any 1 1 or 1 3 octave filter Flat 824 Reference Manual 9 29 09 9 29 09 Menu Items Trigger Setup continued
11. as 7 73 LN Centles Check Menu oi eREDembeneedEIES 7 74 Stats Check Menu iei Bases a Aedes 7 75 Chapter 8 Chapter 9 824 Reference Manual Run Log Check Menu sees eiie 7 15 Time History Check Menu sese 7 16 Intecvals Check Menu sist ite ret Reed 7 16 Exed History Check Menu sssssssssseseeee eere 7 77 Daily History Check Menu sse eene 7 78 Printing a Report 8 1 Connecting the 824 to a Serial Printer 8 1 Printing Reports prep EPI D 8 2 Defining and Printing Tailored Reports sse 8 5 Using the Recall Format SSA and LOG instruments only 8 7 Default Settings Values for the Recall Format 8 8 Prnting a Custom Report ee Rt d E EE 8 23 Performing a Sound Level Measurement 9 1 Configuration of the 9 1 Selecting a Measurement 2 02224 201000600600000000000000000000000000044 9 1 1 enne 9 2 Editing the Microphone Parameters esee 9 3 M G i 9 3 Entering the Noise Floor Values 9 4 Editing the Measurement Parameters sess 9 5 Positioning the Meter oig oet ov D RERO RAO P 9 7 Use ofa Windscreen
12. 11 11 End Settings Men e ee Rene 11 12 iii x Chapter 12 Chapter 13 824 Reference Manual Then Settings Menu eerie ne Hd 11 14 Trigger Settings Menu continued sse 11 14 RT60 Reverberation Time 11 16 RT60 A and RT60 B Instrument Definition sss 11 17 Qualifying Background Noise Rooms RTA ID 11 18 Display Views teen eee dec RU ERR Te Re 11 19 ug SU T M N 11 19 Trigger VIEWS ees cete haee eue e eee v te 11 23 PW P 11 25 Autostore ByTime Spectral History sess 11 29 ByTime Spectrum Check Menu sess 11 30 ByTime Graph Check 11 31 RT 060 noie Rt a 11 33 RT60 Check Menu 2 depo ete qe ett RD beet 11 35 Spatial Ave Views oes SEES UR a Een 11 35 Spatial Ave Check Menu RR ERE DRE VS 11 37 Avg History Check 2 2 2 2 12 40202 4400000000000000000000000000 00000000000000400 11 38 Rooms Views xo eo PE eo eR erret ES 11 39 FFT Optional 12 1 Eeat res oce m ee OR eR e LH tah 12 1 Settings isa dete e ee e e eed 12 1 Settings Descriptions RAE I RIS 12 3 FEE Displays o at ee EE 12 6 E 12 6 EETDGChecle MEMU x enema temen td mt 12 8 THD Total Harmonic Distortion
13. 1 20 Operating Me cise ee RAR a d eie ee C 6 EE 1 18 Terminal Assembly eve IRR ERU ette E d e t He te e EE ete in 1 20 Baud Rate EE 3 34 Block Rede ERE SS 3 26 IBOOKMarks ie ie t d Notte ee o e REO 1 3 By Pati e ee A RR 11 9 C Cables INTE ACE ee ee ie a RT ERE UR EN RE UR A 2 Microphone extension 22 oie Oe eU tr ie ipee C 7 Calibration a ee Be TA E a te 2 14 Change ee eet eie qi pat teten a to ri ee tn Mi 4 3 Display xe e e eR eiie eee te et eei 3 23 Hish R rnge eesneebod dateien eed MU eI E lati dene 4 4 History Variables eio eh ORO ERN ene e eee tet 66 NOISE SiS etter M teds 3 23 Temp Pressure Compensation ee RH EE e de re eret 2 17 Calibrator CAT 200 i nte ei AERE EUR e DURO Re ela pq ed 1 17 DAD 1 17 Recommended t ERAT EEUU 9 3 Changing amplitude range eec REG RINT Dep e E 2 10 2 8 frequency weighting eee RR Rp etie 2 9 Model 831 Technical Reference Manual Index 1v iii IDs deterrere i t en ERE DE RU ENT EO Ed E THER 4 12 Instr ment Definitlotis 230 05 sees pico neto piri 3 29 secondary parameter siete dete e E
14. 10 32 Installation Rete eoe Poe D E 10 1 Locking and Unlocking Setups ccccccccessessecsecescesceeseeseeeeceseeeeeseeeeecaeesaecaecsaecaeeeenaeenreees 10 17 Modifying Setups ERU To NER TERRI RV Rete e 10 9 Opening Setup Disk Files sess nnne 10 12 Printing Translated Eileen ede E RA 10 29 Retrieving setups from 824 2 eene nnne nnne nennen nnne 10 7 KT60 Select Options uc ERR E RR RE 10 34 Saving Setups to Disk Files eese eed ee ee ies 10 12 Selecting a Data Set to VEW TEE TREES 10 27 Selecting Active Measurements sss enne enne nennen nennen nennen 10 21 Setup Window xe c Be A ae ae d er evt 10 6 Specifying a Destination 10 18 Spreadsheet Program sereno a ce 10 31 Starting xoa oe ee 10 2 Storing Setups x Meee Bake cee ee as Ba a ee 10 9 BOOB ar x5 e ear eta tete pe utere te e ie Oi Pr EUR 10 4 Translating Downloaded Files 5 10 25 Viewing Translated File nennen nennen nnne 10 31 824 Utility Software See 824 Utility Model 831 Technical Reference Manual Index 1 A About 8245 it e d cat teu t io nee 3 20 824 display Iu uei c Rats 3 20 this manual
15. 5232 ALL Temperature Calibration Cal level must be 225 48 5233 ALL SERIAL NUMBER Entry secured set ting 5234 ALL Model Number Entry secured setting 5235 ALL Invalid Setting s data block A 50 824 Reference Manual 9 29 09 RTA Settings Commands 553 Filter Bandwidth 1 1 1 3 554 Detector Lin Exp Time Weighting S55 RTA Linear Detector Time ss ssss seconds S56 RTA Exponential Detector Time 1 64 1 32 1 16 32 64 557 Exponential Detector Sample Rate 1 2 1 8 S58 RTA Auto Store Records No Yes 559 Event By Time Pretrigger Samples nnn S60 RTA Event Triggering Enable No Yes S61 RTA Trigger Source Level 12 5 16 0 16 0K 20 0K Flat Hz S62 RTA Store By Time Samples of Event No Yes S63 RTA Arm Mode L lt L Input Time Count S64 RTA Arm Level nnn n dB S65 RTA Arm Time ss ssss Sec for Level and Time Arm Mode Conditions S66 RTA Arm Samples nnnnn 567 Arm Logic Input TRUE Level Low High S68 RTA Trigger Mode L lt L Input Time Count S69 RTA Trigger Level nnn n dB S70 RTA Trigger Time ss ssss Sec 9 29 09 S71 RTA Trigger Samples nnnnn 572 Trigger Logic Input TRUE Level Low High 573 Run via Logic Input Ye
16. 7 15 Time History ere ege ee eO RO eee 7 68 7 76 Clock Tir er SERERE UE UTR eH e ee AREE 3 23 Cen ee ee ee 5 59 comma separated variables 10 31 Communication ne De ORAT RU EH 3 34 Connecting cable 2 esee Ree eei avente e es A 3 Osa Serial printer eoe rete eA e a Tie e verberat 8 1 Connector AC DC O tput connector ORE SUO RO e aod diae d redis 1 13 Control Connector eee mi o ee RO EE REL edad 1 11 Serial Connector xi RETO SEA e REDI tea tree epe iae EDI DG 1 12 Control CORDeCloD c aic manto Ip capote m aie itin ion heiter 1 11 E 3 2 Control Settings AC DC Qt sities E e P e dente rb een etit 7 12 Check Menu eii RUP RUE E RH ER SR V DUE 7 65 TEN e HOO EE PER EN e 7 10 EA cal tone 7 16 heater On MR 7 16 iv iv Index Model 831 Technical Reference Manual ISME doeet eh RO E NOE TA UD ENT e Ee e ER 7 10 LEogicimput x tunc ntotente 7 12 Logic RE RE RE C EORR ee ER ER d 7 13 Logie Output 42 s eee te D Ce 7 16 Logic Output 422 time
17. Absolute maximum AC input voltage 10Vpp Permitted DC voltage range 3Vdc to 30Vdc Frequency Weightings for ISM SSA LOG and TAL instruments Nominal Exact A C Weight Flat Flat with Flat with Electrical Microphone Frequency Frequency Weight Random Random Tolerance Tolerance Incidence Incidence correction correction except for SSA SSA 10 10 00 70 4 14 3 6 0 6 0 0 3 1 8 2 2 12 5 12 59 63 4 11 2 4 2 4 2 0 2 1 5 2 0 16 15 85 56 7 8 5 2 9 2 9 0 2 1 2 1 8 20 19 95 50 5 6 2 1 9 1 9 0 1 1 0 1 5 25 25 12 44 7 4 4 1 3 1 3 0 1 0 9 1 1 31 5 31 62 39 4 3 0 0 8 0 8 0 0 0 7 0 8 40 39 81 34 6 2 0 0 5 0 5 0 0 0 7 0 8 50 50 12 30 2 1 3 0 3 0 3 0 0 0 5 0 5 63 63 10 26 2 0 8 0 2 0 2 0 0 0 5 0 5 80 79 43 22 5 0 5 0 1 0 1 0 0 0 5 0 5 100 100 00 19 1 0 3 0 1 0 1 0 0 0 5 0 5 125 125 00 16 1 0 2 0 0 0 0 0 0 0 5 0 5 160 158 50 13 4 0 1 0 0 0 0 0 0 0 5 0 5 200 199 50 10 9 0 0 0 0 0 0 0 0 0 5 0 5 250 251 20 8 6 0 0 0 0 0 0 0 0 0 5 0 5 315 316 20 6 6 0 0 0 0 0 0 0 0 0 4 0 6 400 398 10 4 8 0 0 0 0 0 0 0 0 0 4 0 6 500 501 20 3 2 0 0 0 0 0 0 0 0 0 4 0 6 630 631 00 1 9 0 0 0 0 0 0 0 0 0 4 0 6 800 794 30 0 8 0 0 0 0 0 0 0 0 0 4 0 6 1000 1000 00 0 0 0 0 0 0 0 0 0 0 0 4 0 6 1250 1259 00 0 6
18. LOG SSA aii nte di Pa 7 23 PK Excd Evl SSA irda pei p iced 7 24 Pk Excd Lv12 LOG SSA 7 24 Hysteresis LOG SA iet NOE ER ANTA 7 24 LOG and SSA Wind Tach Settings sss 7 25 Setup of Wind Tach Function sss 7 26 Walid Scale saec ten oot tu ed ers 7 27 Wind Units ree Rand ia 7 28 Dine ction Units eine per eret pepe Ede edge eee 7 28 Wand Fach Bn ble 3 pt etd qe e tot tases dota a uae 7 29 Windy Threshold x Re at ie Ride 7 29 Wand Exceedance 7 29 Windy Hysteresis icc sme iere dede ede nee Te RS 7 29 Wand Pause Enable e oe tert tpe tpi itive katie ined 7 30 Pulse Trigger 41 2 4 400 40 440 001000000 00000000000000000000000000000013 7 30 P ls SOULE is p n n etit e 7 30 LOG and SSA Time History 7 30 Hist Enable LOG SSA in crai 7 32 Hist Period LOG SD i dut t an a EPOD Otis ne 7 33 Period Units LOG 5584 5 ee vete E 7 33 Other Level EOG 0Rly 4 ete e the etre 7 33 LEAO EASY D PAE E nennen 7 34 Advanced Time History LOG SSA ssessssssssseeeerr 7 35 Marker Text LOG SSA p d teens 7 35 LOG and SSA Interval Settings essere 7 36 Intv Enable LOG SSA
19. The following is an example of how to select the RMS Detector within the SLM view 824 Reference Manual 9 29 09 9 29 09 Step 1 Press the amp or W keys to highlight the current RMS detector Slow Fast Impl SPL iam 1 A inn L x e Sa 4dBA Gain Step 2 Press the 4 D key to change the selection The table below shows how to use the arrow keys to navigate through the settings on the SLM display A V Detector Slow Fast P Impulse P A Weight A c 9 Flat P A Second Value Leq SEL Min Max P Peak P 2 eau AD C f Flat b Gain or Range oA 10 20 P 30 40 ae I Low Normal P Quick Start 4 23 4 24 824 Reference Manual 9 29 09 System 824 Views This chapter introduces you to the various ways of viewing measured data for a particular setup or ID of the System 824 Specifically this chapter covers the following topics Status icons General views e SLM RTA specific views Logging SLM specific views 9 29 09 System 824 Views 5 1 Status Icons and Indicators When using the System 824 you will encounter a number of different display views Each display contains an instrument status icon the upper right hand corner of the display This icon changes according to the current state of the instrument System under range near noise Latching floor indic
20. 1 16 Accessories and Optional Equipment sse 1 16 Connecting Internal or External 1 18 Using the NiMH Battery Pack sssssseeeereeeeenneennn 1 18 Using Alkaline Batteries or Individual NiMH rechargable cells 1 19 Using the AC Power Adapter 1 20 Chapter2 Overview 2 1 System 824 Setups or Instrument Definitions 4 2002002 0 000000000000000 00 14 2 1 Instrument Definition ID 2 2 Write Protect Delete Write Enable IDs 2 2 SEM amp RTA SSA aede ERE ERN RERO 2 2 SEM USN nitet td er REO YA 2 4 LOG eaten totam get 2 4 Selecting a Measurement Setup nennen 2 6 Performing a Measurement SLM amp RTA 55 2 7 Stop Pause and Back Erase Functions sss 2 8 Stopping and Starting Measurements 2 8 824 Reference Manual Pausing Measurements TERREA 2 8 Back Erasing osa a nei etna ev d RENS 2 8 Changing the detector of the displayed SPL 2 8 Changing the frequency weighting of the displayed SPL value 2 9 Changing the displayed secondary parameter sess 2 10 Changing the frequency weighting of the displayed Lpeak value 2 10 Changing the amplitude range or input Gain see
21. _w Leg SEL Reading __w SEL G3 3 Exceedance Duration Duration 88 5 ai i a4 Excd Number Excd b Display 9 29 09 The following explains each of the display s components Display label This shows the current display for example Exceedance Number Exceedance display shows each exceedance record in the order that it occurred The exceedance number indicates the order of the displayed exceedance in relation to the other exceedance records Exceedance Date Time The Event Date Time shows the time and date that this exceedance occurred Leq Reading The Leq Reading shows the Leq for the currently displayed exceedance SEL Reading The SEL Reading shows the SEL for the currently displayed exceedance Exceedance Duration The Exceedance Duration shows the length of time this exceedance lasted The Excd b display consists of six major components Display label Exceedance Number Exceedance Date Time e Peak I Reading Peak II Reading System 824 Views 5 53 e Max Reading The Excd b display is shown below Display label amp Eccc b Exceedance Date Time 18Jun1999 89 49 45 Peak I Reading Peak I 95 3dBF Peak II Reading Peak II 95 ZdBh Maximum level during 88 GBA ir at ag Excd Number Excd c Display 5 54 The
22. 5 19 Logging SLM Specific Views esses eene 5 23 Current SLM and Overall SLM Views essen 5 25 Current SLM Overall SLM Display a SPL sss 5 26 Current Overall SLM Display b Times eee 5 28 Current Overall SLM Display c Min Max sese 5 29 Current Overall SLM Display d 0 4000 5 29 Current Overall SLM Display e 5 30 Exposure Views oe tet ae ERE E EE 5 31 Exposure Display eee RARE EBEN Hed 5 32 Exposure b Display sess 5 33 Exposure c Display eee deeem eins 5 34 In Centiles Views saci 5 35 En a 5 35 En b Display tet teer eai ee 5 36 Stats VIEWS e 5 37 Statsa Displ y ne e Re S e Rees 5 38 Stats b Display oed as UE E de eee Di 5 38 Stats c Display esee eee etie de he deed 5 39 Run Log LOG amp SSA tenete 5 40 Time History tette RO ROUES qoe m watt 5 42 Single Other Level RR S TRE Pe ES 5 43 Multiple Other Levels t ege mr na 5 43 Intervals 425 geo a ene eie ome REC 5 44 Intervals a Display ettet eee ERO e Rete peel 5 44 Intervals b Display ipe RR EUREN HN EE 5 46 Intervals c D
23. SL Write protected IDs Those with a symbol of a padlock to the left are user defined IDs which have been write protected Like the permanent IDs these can be selected modified and used for a measurement but the name must be changed when stored Edit Settings rj Logging POSU 2Lodgdging Indicates ID is write TomaGur protected PSLM amp aRTA SSA Preparing for a Measurement If data has been taken the prompt WOvexra Reset Requiredt Reset Bie Cancel will be shown Press the check y key to reset data and edit the setting gt Select and use a different ID make it the Active ID 4 16 If the Active ID will provide the desired measurement press either the Setup A key or 4 to exit from the Setup menu The System 824 is now ready to perform a measurement according to the Setup represented by the Active ID If the Active ID is not satisfactory for the measurement the following options are available 1 Modify the Active ID as required 824 Reference Manual 9 29 09 Selecting a Different ID Accessing the Settings Menu 9 29 09 3 Select a different ID make it the Active ID and mod ify it as required Use the W keys to highlight the desired ID and make it the Active ID by pressing the Y Check key This will activate that ID exit the Setup menu and display the main data view The instrument is ready to perform a measurement by pressing S Ru
24. lett tie ee e 12 17 Linear Units Display 2 reete tert egeret tre te ripe Tere ere ug ende 12 14 Overload SKID RE vete 12 4 Model 831 Technical Reference Manual Index iv vii Repeat measurements x oro rar n EH e ve irre 12 4 Settings Descriptions oie dee re RU ee e e de ee edis reed 12 3 Set ngs 12 1 Snapshot Check ueniet eee te tae ien EUR ee os 12 12 Snapshot Data Storage ee Ee ie eie nein 12 11 Snapshot Automatic aate oen Repeat utente iss is 12 6 THD Measuremient eshte eee ev e Rn p oer ORT tae d 12 9 Time Domain Windows aceto siete e t e E EOS e ESAMI EON 12 4 ZOOf cene avete E ON PERE Nate mer ee citt 12 7 Filters 1 1 1 3 Octave Filter Shapes iet ete de eee e eee aen C 20 Fractional Octave Bandwidth 7 10 Fractional Octave Detector tust ere te e 7 9 Fractional Octave Display e et rete eerte tee e 5 11 Fractional Octave Fast Autostore ssssssessesesseseeeeee eene ennt nnne ener ener nnns 11 1 Fractional Octave Weighting 7 10 Fractional Octave general 5 ere ee e Hee ien pei ei eec 6 3 Formatting Conventions E ero Reg eei eiie tnl 1 6 Bree fel detec etic I
25. Broadband Bil Spectrum Locate gt Settings gt Graph Following is a chart of the Time History check menu with a description of each menu item Menu Items Purpose Broadband Allows you to view the broadband Spectrum history graph or the spectral data Locate Locates a specific time history record Settings Modifies the time history settings Graph Changes the scaling of the instrument s time history graph Run Log Check Menu Press the Check key while viewing the Run Log display and the following check menu appears 9 29 09 Using ID Setting Files 7 69 i O Find Locate 0 Following is a chart of Run Log check menu with a description of each menu item Menu Items Purpose First Locates the first Run Log record Last Locates the last Run Log record Find Finds the specified Run Log record Locate T H Displays the Time History Ln Centiles Check Menus There are three different Check menus contained within the Ln Centiles views Press the Check key while viewing the Ln Centile s broadband displays and the following check menu appears Ln crest Start 1 415 Ln 1 Fercent 7 70 824 Reference Manual 9 29 09 9 29 09 Following is a chart of the Ln Centiles broadband check menu with a description of each menu item Menu Items Purpo
26. Entering Settings Option Settings Settings are entered with the Set command The syntax for the Set command is S ET setting number setting value S ET setting number option text where setting number is the setting number setting value is the desired setting and option text is the textual setting for the option settings those that have one setting from a list of possible settings 9 29 09 Option settings can be set in two ways a option number and b actual option settings text a Option Number Syntax Response S et item number option number lt cr gt lt lf gt Example S9 3 sets setting 9 Baud Rate to option 3 which sets the baud rate to 9600 Example S674 1 sets Excd History Enable to Yes Example S95 0 sets Hist Period Units to 1 32s Example S95 1 sets Hist Period Units to 1 06 b Option Setting Text Querying an option with a flag of 2 will return the settings value enclosed in brackets as needed when using the option text syntax Option settings texts is preceded by a semicolon and enclosed by brackets Option settings text must include the same number of characters that are given when queried including spaces which are indicated below with Syntax Response S et item number option text lt cr gt lt lf gt Example S9 9600 sets Baud Rate to 9600
27. Hz Type 1 limits Graph 6 The 824 in normal range with the 377B41 microphone and windscreen 824 0170 Model 2541 Serial f 5636 Normalized to 1000 00Hz O Tested 05 20 99 16 47 31 by Leroy Harbaugh ote normal range with wind screen Reference Mic Model 4133 Serial Number 1424039 Tested 05 20 99 11 20 15 3 0 dB 1K Hz Type 1 limits C 31 Graph 7 The 824 in high range with the 377 41 microphone and windscreen 824 01 Note Refere 3 0 dB Larson Davis Model 2551 Serial 0099 Normalized to 1000 00Hz 8 0 xy Tested 03 02 01 16 31 06 by James Higley Note Reference Mic amp Model 4133 Serial Number 1424039 Tested 03 01 01 08 20 13 4 0 Tested 05 21 99 11 56 04 by Leroy Harbaugh high range with wind screen nce Mic B amp K Model 4133 Serial Number 1424039 Tested 05 20 99 11 20 15 70 Model 2541 Serial 5636 Normalized to l1000 00Hz 0 Type 1 limits Graph 8 The 824 in normal range with the 2551 free field microphone Prepolarized Microphone Type 1 limits C 32 824 Reference Manual 9 29 09 Graph 9 The 824 in normal range with the 2551 free field microphone and windscreen Larson Davis Model 2551 Serial 0099 Norma
28. sese 12 9 jSIBEGTT MC EE 12 10 Snapshot aes e e ERA ERE 12 11 Snapshot Check Menu e RR ERE TES ERRAVRUUS 12 12 EET Calibrations ioe tis ett epu Rod ten d E ecd s 12 13 Calibrating dB to a Different Reference 2 12 13 Displaying Amplitude in Linear Units sse 12 14 Setup of Linear Units Readout sse 12 15 Frequently Asked Questions Concerning FFT sss 12 17 AUD Optional 13 1 Connecting the Test Systemi 2 oe e iae DU phe 13 2 Selecting 824 AUD Operation Mode sse 13 3 824 Reference Manual Microphone Sensitivity Calibration 13 4 AUD MOdes etri gi ertt 13 4 View Menu inttr edite a e d E 13 5 SEM RATASUbtieni u ise oia STA crei Rais 13 5 EET 13 5 Pulse FM Submenu iie RR des 13 5 Display Sequence 3i cO Mee i OR 13 6 SEM RTA Live Display iere tentes 13 6 SEMEERTA Eive Checks Menu uper et e een 13 7 Any Level a b and c Displays sse 13 8 Any Level Check Menu RR tere teet terga hots 13 9 Linearity Display eene emen nennen 13 10 Manual Lock eee ende Dien igen 13 12 Automatic Bock de ette metet aede pes 13 12 Linearity RTA Check Menu eene 13 13 Linearity FET Display ote e Rp 13 14 Manual t ate Res 13 16 Automatic Lock ccce epe er he ees 1
29. R32 ALL Short status string and reset alarm tripped status A short status string for R3 1 R3 2 has a 6 character response 12 The first character is s when stabilizing or a space when stable The second character is the current mode S for Stopped R for Running P for Paused for Cali brating V for View mode O for stopped with over all data reset and C for stopped with Current data set reset The third character is the instrument Lock Status and is either an L or a U The fourth character is the Logic Input Status and is a 1 if high and a 0 if low The fifth character will be an a if an Alarm has been detected otherwise it will be a space The sixth character is the modified status of the active setup ID space for unmodified and A for archive 824 Reference Manual 9 29 09 R3 3 ALL Status of Active ID ccc Archive Status A indicates that it has been modified since being uploaded Changed Status indicates that it has been changed and not saved back to it s ID ID from file F indicates that it has been recalled from a data file R3 4 ALL Active File Number ccc R3 5 ALL Reads out the number of DEMOs used R4 x ALL Current SPL nnn nn dB R5 ALL Runtime hhhhh mm ss s R6 ALL
30. gene me E TOTAL Bytes Sun Ihes 6 58 TOTAL Bytes Day Intv TOTAL Bytes Day Day mpi ines 10 8 11 copy to ne 26 Daily History Memory Calculation Latte es Needed Basic Daily Record 175 Daily Save 6 Ln Values 18 Daily Save Ln Table TOTAL Daily Bytes Day Sun Ihes 12 to 14 copy to lhe 27 9 29 09 E 3 Time History Memory Calculation Resolution Other Level Bytes per record Used 1 0dB None 1 0 1dB None 1 0dB Pk Il Pk I Lmax 0 1dB Pk II Pk I Lmax 2 2 4 1 0dB 1 plus number of v Advc enabled levels Calculate 0 1dB 2 plus 2 times each v Advc enabled levels Calculate A Leg 4 Max 8 Leg 4 TOTAL bytes Hist Record Hist Records Day 24 hours divided by Hist Period in hours Select the appropriate number of bytes from lines 16 to 21 above Enter Number Calculated i e 24 60 sec 3600 sec per 1440 8 1 440 TOTAL Hist Bytes Day Multiply lines 22 amp 23 copy to line 28 1320 Memory Use per Day Calculation Bytes 18 720 Interval History bytes day 11 1368 Exceedance History bytes day from line 5 Daily History bytes day from line 22 212 41 820 2 20 40 n x 20 bytes record Calibration Log bytes day 1 17 i7 number of Cal Log records day ETT Time History
31. ien EEA Titan citet tort Ao hen E hase eot E 7 43 SLM Check Menu Options eoe ette te t Oe 7 62 Smart Charger cete etuer aede t Pe Tene tet e EO UNSERES ERR 3 6 Sound average level feto nte ees ai ee ep re ERE D 2 day night average D 3 energy average Leq eee eee eise ite ett atten ae acd de i re e ta D 21 eXpOSUTE ER epe er HP eere te p D 18 exposure leyvel 42335553 oon vehe edat e aa etus en ti Eddie D 18 fixed average eee d n IER REC UR RUE RUE e ER GNE E ORE D 20 PIOSSA o C D 17 e Ree d Hn ed D 21 Instantancols metit nomen iud mettendo D 20 uui ae D 21 MOVING AV CTALE Rn teet tapete dil D 19 pressure ee eee UP ete Per ini eer re erre D 19 sound pressure level SPL Lp aieea e aeien eri i D 20 unweighted peak ciet en tete e thins D 21 weighted pedak cette erat EATER e eno o te eI ERE RIEN D 21 Sound Exposure RU IRURE een eite te 6 9 Sound Level threshold Lit ere E RR EE OE HERE RE ene ERR RS D 22 Sound Level etos Sere eer tet io Ce te Debe 9 1 AVeragIng June eH i ee ie e
32. 22 10 10 Saying Setups to Disk Files ERR ERA RR 10 12 Opening Setup Disk Files sess 10 12 Creating New Setup cce ee e e E ERAS 10 14 Renaming an Existing Setup 10 15 Deleting an Existing Setup 10 16 Locking and Unlocking 10 17 Downloading Measurement Data 222 10 17 Specifying a Destination File sse 10 18 Changing the Download File esee 10 20 Adding Notes to a download file sse 10 21 Selecting Active Measurements or Data Files sse 10 21 Downloading the Measurement 1 1 10 22 Explanation of files in the 824 Utility Directory 10 24 Translating Data from a Downloaded Binary 1 10 25 Selecting Data set to View node eee eR 10 27 Printing a Translated File 3i REG Rute 10 29 Viewing a Translated File Within a Spreadsheet Program 10 31 Additional Features ted etit oreet 10 32 Chapter 11 optional 11 1 Settings Men scott teet n toU ten Menuinienau ius 11 2 Settings Descriptions idees dee e nr 11 6 RTA Settings Menu ue EUER RE HU qe Ree 11 6 Autostore Settings Menu eene 11 8 Atm Settings Menus ERROR RR 11 9 Trigger Settings Menu
33. 4 SPL history graph 9 29 09 The following discusses each of these display components Display label This shows the current display in this example SLM Current a The display represents both Current a and Overall a display Current reading and weight setting Displays the current SPL reading This level is also shown graphically by the bar on the far right of the SPL history graph The frequency weighting for SPL can be either A C or FLAT Detector setting The current detector is indicated for example Slow SPL and can be Slow Fast or Impl Elapsed time This displays the length of time the current measurement has been running It will reset to zero when the Reset key is pressed Current SLM only It will also pause when the Pause key is pressed and then continue when it is pressed again The timer is displayed as mm ss ss hh mm ss or hhhhh mm SPL history graph Shows a recent history of one second Leq readings The far right bar displays the current SPL reading As readings are taken they are placed onto the scrolling graph from right to left once per second System 824 Views 5 27 Current Overall SLM Display b Times The Current Overall b SLM or Times display consists of four major components Display label Start date time Elapsed time End date time The SLM Current b or Times display is shown below Display label 9 SLM Current b Began Start
34. Start Date and Time ddmmmyy hh mm ss R7 ALL Current Runtime hhhhh mm ss s R8 ALL Current Start Date and Time ddmmmyy hh mm ss R9 w LOG Overall TWA Time Wght Avg nnn n dB R10 SSA ISM Overall Exchange Rate Text LOG Rll w SSA ISM Current TWA Time Wght Avg nnn n dB LOG R 12 SSA ISM Current Exchange Rate Text LOG R13 w LOG Overall SEL nnn n dB R14 w SSA ISM Current SEL nnn n dB LOG R15 x LOG OverAll Minimum Level nnn n dB R16 x LOG OverAll Lmin Date and Time ddmmmyy hh mm ss 9 29 09 R17 x SSA ISM Current Minimum Level nnn n dB LOG R18 x SSA ISM Current Lmin Date and Time ddmmmyy hh mm ss LOG R19 x LOG OverAll Maximum Level nnn n dB R20 x LOG Lmax Date and Time ddmmmyy hh mm ss R21 x SSA ISM Current Maximum Level nnn n dB LOG R22 x SSA ISM Current Lmax Date and Time ddmmmyy hh mm ss LOG R23 w LOG OverAll Peak Level nnn n dB R24 w LOG OverAll Lpeak Date and Time ddmmmyy hh mm ss R25 w SSA ISM Current Peak Level nnn n dB LOG 26 w SSA ISM Current Lpeak Date and Time ddmmmyy hh mm ss LOG R27 w LOG OverAll UWPk Level Peak Level 1 nnn n dB R28 w LOG OverAll Luwpk Date and Time ddmmmyy hh mm ss R29 w SSA ISM Current UWPk Level Peak Level 1 nnn n dB LOG R30 w SSA ISM Current UWPk Date and Time ddmmmyy hh mm ss LOG R31 LOG OverAll RMS Exceedances
35. 18 0 Mic 1995 26 Hz C 44 824 Reference Manual 9 29 09 Graph 23 824 in the XY plane fitted with the 2551 microphone 4 kHz Larson Davis Model 2551 Serial 0099 Normalized to 1000 00Hz 8 0 xy Tested 03 02 01 16 31 06 by James Higley olarized Microphone 10 0 14 0 dB 18 0 Graph 24 824 in the XY plane fitted with the 2551 microphone 8 kHz Larson Davis Model 2551 Serial 0099 Normalized to 1000 00Hz 8 0 xy Tested 03 02 01 16 31 06 by James Higley olarized Microphone 9 29 09 C 45 Graph 25 824 in the XY plane fitted with the 2551 microphone 12 5 kHz Graph 26 824 in the YZ plane fitted with the 2551 microphone 1 kHz C 46 824 Reference Manual 9 29 09 9 29 09 Graph 27 824 in the YZ plane fitted with the 2551 microphone 2 kHz Larson Davis Model 2551 Serial 0099 Normalized to 1000 00Hz 8 0 xy Tested 03 02 01 16 31 06 by James Higley Note Prepolarized Microphone Reference Mic Model 4133 Serial Humber 1424039 Tested 03 01 01 08 20 13 6 0 0 Graph 28 824 in the YZ plane fitted with the 2551 microphone 4 kHz Larson Davis Model 2551 Serial 0099 Normalized to 1000 00Hz 8 0 Tested 03 02 01 16 31 06 by James Higley Note Prepolarized Microphone Reference Mic Model 4133 Serial Number 1424039 Test
36. 9 29 09 C 27 LD Model Note PRM902 SN 824 Serial f 1131 Normalized to l1000 00Hz 0 Tested 06 04 01 14 18 11 by James Higley 0258 with 2551 SN 98 Reference Mic B amp K Model Graph 7 The 824 in normal range with the 2551 free field electret microphone showing random response with the random corrector 4133 Serial Number 06 04 01 08 09 21 1424039 Tested The 824 was oriented with the LCD facing up for these tests NOTE The graphs below show typical results C 28 Microphone Response Tests with 824 The following graphs show the effects on the performance of the 824 caused by the following Windscreen nstrument Case High Range 824 Reference Manual 9 29 09 Graph 1 The 824 in normal range with the 2540 microphone 824 0170 Model 2540 Serial 4187 Normalized to l000 00Hz 0 Tested 05 21 99 10 59 46 by Leroy Harbaugh normal range Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 05 20 99 11 20 15 3 0 dB E 1 8 0 6 dB 0 6 dB 6 6 dB 200 Hz Hz ZOK Hz Hic 0 Type 1 limits Graph 2 The 824 in normal range with the 2540 microphone and windscreen 824 0170 Model 2540 Serial 4187 Normalized to 1000 00Hz 0 Tested 05 21 99 11 35
37. A 34 824 Reference Manual 9 29 09 Example S74 Yes sets Excd History Enable to Yes Example S95 1 32s sets Hist Period Units to 1 32s Example S95 1 0s sets Hist Period Units to 1 0s Numeric Settings Syntax Response S et item number setting value lt cr gt lt lf gt Example S62 120 sets RMS Excd Level 2 to 120 Character String Settings To include leading spaces in a character string setting precede the character string with a leading single quote or grave accent ASCII 96 or hexadecimal 60 Syntax Response S et item number character string lt cr gt lt lf gt Example 52 ABC Acoustics sets Name to ABC Acoustics 9 29 09 Template Settings For example when entering a date the month day and year are entered in that order two numeric digits each and are separated by The display shows date month abbreviated and year in that order normally or in year month and date for ISO 8601 format ddmmmyyyy or yyyymmmdd Syntax Response S et item number mm dd yy lt cr gt lt lf gt 28 05 23 89 sets Timer Run Date to 23May1989 Times are entered in hour minutes and seconds order and are separated by 24 hour clock time is used i e hours 0 to 23 Syntax Re
38. D 2 Criterion Duration 41 11 000000000000000000000000000000000000004 D 3 Criterion Sound Exposure D 3 Criterion Sound Level LG 4 x hec a eiii ni eed D 3 Daily Personal Noise Exposure LEP d esee D 3 Day Night Average Sound Level DNL Ldn esses D 3 Decibel dB o RES ERUIT ntn D 4 Department of Defense Level 14 22 002 0000000000000000004 D 8 ln M M D 8 D tectotz unice EET a PO OR ER Osee TP OD GRE TUS D 8 Eight Hour Time Weighted Average Sound Level L TWA amp 8 D 8 Energy Equivalent Sound Level Leq see D 8 Exchange Rate Exchange Rate Factor q Exposure Factor k D 8 Ear D 9 Bree Field up ORI D 9 Frequency Hz rad sec sete ne D 9 Frequency Band Pass 4 020 20 1 12000 0 D 10 Frequency Filter Weighted essen D 10 iecit dubie Posten orco D 12 Level dB ii e RE e RE E RR D 12 Measurement Duration T sss D 12 iii xiv 824 Reference Manual Microphone Guidelines eee dide D 12 Near Field ts cst tite ts D 15 Doce D 15 No
39. ER ere nade ER E edes 1 1 ped cq 3 8 AC power adaptor i e eec eot et esee i e e ene ec re Seo e OE pens 1 19 AC Susceptibility 3 2 e RE REC EE E RET F 7 Above tO V M te eite ast pct n re PE F 6 AC DC Output COBDDECI E a i ere t es ER ERE EEUU 6 5 control settings erede RE end aestus ee ees 7 12 Igi RE 6 6 Accessories Optional Equipment 1 16 M 4 13 Advanced Time History marker text ote De Ur E OM ADR ee 7 35 Allocated IDs Ge e ie ed 3 29 Any Data Check Menu eere PE ORE ER HEU cope 7 73 SUI pe 2 3 9 5 Read Commands encrassir eye Ub ae I RI ee 25 Any Impulse VOIE M 5 8 Any Time WAEW P 5 9 Keys 4 rer tases e ete ey RAN P 3 11 AUD sks 13 1 Any Eevel Displays tede eU ae 13 8 Display Sequence oA eh tee e Aer E pe Cir Ate p 13 6 EET DISpl y e s nr ota heec ee EET D GER EDEU 13 25 PET St Ci 2e A pU este in eats 13 5 Flatness FET Display tete eto rei tees Oe eripe Eee oe E nud 13 18 Linearity EET Display ssc nee ht
40. Live M Live 5 Average 9 4 54 21 Ww Maximum We Max Windspeed Jb 0 Date Time n Wind Exceedance P Timez B Windy Threshold 4 84 36 X The following explains each of the display s components Display label This shows the current display for example Wind b Live Windspeed and Direction This displays the instantaneous value of windspeed and direction Average Windspeed This displays the average value of windspeed calculated since the initiation of the measurement or since the last data reset Maximum Windspeed and Direction This displays the maximum value of windspeed and its direction since the initiation of the measurement or the last data reset Date Time of Maximum Windspeed This displays the data and time of the maximum windspeed Windy Exceedance Data The Windy Exceedance Data includes the value of the Windy Exceedance Level in this instance 40 11 and the number of times the windspeed exceeded this level Windy Threshold Data The Windy Threshold Data includes the value of the Windy Threshold Level in this instance 5 04 and the percent of the time that the windspeed was above this level Wind c Percent Display The Wind c Percent display consists of three major components 9 29 09 System 824 Views 5 71 Display label Live Windspeed Live Wind Direction e Percent Windy Condition Windy Directional Distri
41. Report Settings Lower Level Report Settings Description Unformatted No A dump of all Read Query and Interval remote commands Multiple values are comma delimited 8 18 824 Reference Manual 9 29 09 All Long Report Template LOG instrument Data Report Yes This shows general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Log Report Yes The run stop log and with the date and time of each run stop Setup Report Yes Print the settings and their values for the LOG instrument SPL Histogram Yes The 6 Ln values Lmax Lmin and a bargraph of the level distribution Intv Report Long Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in the short report The Long reports adds the Ln values for the Interval period Hist Report Yes Leq for each time history period Print Range Intv Report Long Lowest Record 00000 You can customize the interval report by choosing the long or short report Selects the lowest interval record to be printed Highest Record 65535 Selects the highest interval record to be printed Hist Report Yes You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time history record to be printed Highest Record 799999 Selects the highest
42. Step 3 Highlight Delete Last and press the Check Y key Delete Last a Data File LOGI 92 16 19 02 7419 bytes Free Memory 25 Bra 466013 475149 This display shows the last record that was stored along with the date and time of the data the instrument type it is 824 Reference Manual 9 29 09 Choosing Open also allows you to delete individual records from the file after it has been opened See the next page for instructions deleting individual records In essence this will UNDO the storing of a data file Deleting Individual Records 9 29 09 recorded for the bytes used by that record and how much memory is available Step 4 Press the Check key to delete this file The fol lowing menu will appear Delete Last B De lete View Back O Step 5 Highlight Delete and press the Check key The record is deleted If the last record was a data file then the following choices will appear DEL Choosing DEL will erase the file and all of its con tents Open Choosing Open recalls the file into memory the File record is deleted and the data in memory marked as if it had never been stored This allows you to run the instrument again and store the old data and the new data just acquired into a new file Cancel Choosing Cancel cancels you out of the Delete File function and returns you to the previous display After sel
43. 3 35 T onitor Durmbers ete te qe mte Red e t e a E So RE dS 75 N Near Field ACOUSTIC e A D 15 E es D 15 BI OSS ALY E CS en R D 15 Noise ambient iostan e ina a a i a a a a D 15 Background dor reti E E E E esc iter REET D 15 COMPCNSALE E P A 49 daily personal exposure ssssessssesseeseen eene ener enne ennt D 3 dose D 5 eee e RERO GR E D 16 CXDOSUIG scene oui ves ows e eee ade D 17 ee i e Gane 49 ids Em 3 23 BlOSSAEY oA e c D 2 D 15 iv xii Index Model 831 Technical Reference Manual Inherent eere SEHR ER F 5 PUNK c sourds PE iren n WR IER EH ER DS D 16 projected noise dose ce o eem tie D 17 single event exposure level asesmen e te eei te Sa t aeter ie taba tete D 17 WHILE elite eee Pere OUR PT UU tele m onn D 16 Note adding to downloaded file eee tenere recen 10 21 O Off TMG ack eee Rte hentia Asi bos dro Ere 13 23 OnitiTie nn Med orte ese 13 23 OSHA nl rr D 17 Othet aiio ai eh Std ees HA dad e pte ese ab Re ee er RE p pedo ipee t ae i et 7 73 Other Level VIEWS iyo far
44. sseese E 2 Daily Records Daily History E 2 Time History Records Time History Enabled sss E 2 Other Histories and Memory 12 1 2 1 2 002 00000000000000000000000004 E 2 Estimating Memory Usage 02010 E 3 824 LOG Memory Usage Worksheet essen E 5 824 SSA Memory Usage ourense a aE E aE AEEA E a a E E S E 7 Interval Records Intv History Enabled sse E 7 Time History Records Time History Enabled sess E 8 Appendix F SLM Testing to IEC61672 1 F 1 iii xv 824 Reference Manual Reference Sound Pressure 4 00 F 1 Reference bevel Range toi sana owes F 1 Microphone Reference 24 1 1 F 1 Average Frequency Response Corrections 0 000 2 Periodic Testing of A Weighted Sound F 4 A Weighted Sound Levels at Upper and Lower Limits of the Linear Operating Ranges donent F 5 Electrical Signal Input Device esses 5 5 o cet tudin lates 5 Maximum Sound Pressure Level eese F 6 Power Supply Voltage F 6 Display Device e e ar Nec
45. a 05 loaded file in the default location R 052016 003 slma C Program Files Larson Davis 824 05Jul1 6r 005 sImdl us 5 05Jul16r 006 slmdl Utility 05Jul18s 002 slmdl 15 28Jun15r slmdl lj 28 Jun15s slmdl 1 Sys Settings 1 Settings E 1 SSA Settings 0 0 E E EH EH E 4 SSA Run Stops E 1 SSA Summary 10 26 824 Reference Manual 9 29 09 Each downloaded file will contain several records depend ing on the type of setup used and the data stored Internet Explorer Larson Davis Downloaded measurement file Data translated from the Downloaded file 1 Cal Settings 1 55 Settings 2 55A Run Stops 1 Summary TEMP Selecting a Data set to view After the downloaded file 15 located click on the data you wish to view lolx a 824 Utility File View Setups Data Help amaA SLM amp RTA Summary C Program Files Accessories Adobe File Translated C Program Files Larson Davis 824 Ltiity C licen bor Model Serial Number 824 0271 Borland Firm Software Revs 2 101 1 610 H Common Files Name Enter Company Name H E Creative Descerl Enter Address Line 1 H E DevStudio ICwInteret Connection Wizard Internet Explorer Larson Davis E 824 Utility 6 O7Sep2ts simdl a 1 Setup a 1 Sy
46. 5 34 NCBI ee ee 5 35 En b Display i eno teo ee eet tege ta hee e ed epee teorie 5 36 Stats b Display 4i so RE reae e e t dete es 5 38 Stats CDiIsplay iine ore ete A E E I aem 5 39 Duration measurement are oap sete nte tete teen ie bet lea teeth Td D 12 E EA Tore pe reae d ea eee ep eer s 7 16 EEPROM eee itd 3 19 Eight Hour TWA tree eer ten D 8 Electrical Input e eee e c e RRA a ee e NE ie een eS F 5 Electrostatic Discharges EFECT On 824 coitus seche M F 7 Entering Settings iot rectitudo ates edes 33 Exceedance OTST AM coef vac tee eene ee e e E RED OU IIO DUREE 6 8 History su RES RU he ERE 7 77 iv vi Index Model 831 Technical Reference Manual History Display i Berto eleg tet HE 5 52 ro aede aeter Te B PR EF RI Re pe 7 40 Time History Display ee e OR REED RE e eR e Ree ee 5 55 Exceedance History Enable eect eae atim 7 40 oem ntn a tnbus tento icit oe tese 7 41 Minimum Duration 5 eater e D Oe PUER cde ease ood 7 40 History ecce tte tte etse eee e e EA Sete eed e ee e DOT Y 7 41 Tame History 7 41 Tamed Exed Period ied neo tie ap rv ete qoe d rid 7 41 Trigger i
47. 71 Report All Long Report me epe eves d e PR RUNG 8 14 Short Report tr eee t DR EO TODA IERI ERST ee eed 8 14 a Ja hte oh 8 23 Data tote oen A RED 7 43 History Report ans eR eR RR RR EET RERO eee edere ec ede R 7 45 Interval Report i eee eee deret eter eta Reo Gr e v nati dte 7 44 Peak 1 Histogram eredi ete e ee eH eae EP 7 44 Peak 2 Histo grant iei vitiata dfe 7 44 PDDE e 8 2 Recall Format 2st tete i bep toca testen Ros E Pie 8 7 REA a en ate 8 26 7 43 SPE Histogram ee e ER REIR UT RR ER COR RERO Te Ee RS 7 44 co ted ense ab ease oe teer deo inito teeth stus tees eames Ue e 8 8 Tailored 2 eo ER ROT ERU eo teet ere Ree 8 5 Reset Using key sequence ee ee a e de e ve ei A e tere te tel G 9 Reset Key ep P 3 9 RF Emission GTC ALES Ee Sole oie senshi cout neto n od Ote o i ERE RIEGO tama F 6 group classification saei Ce ee dei Re de e IRE ERES C 3 RF Susceptibility Greatest temere n E ed ete eee ta pb dett F 7 heo nM o bend BAe ace ete She ae ces 13 22
48. 9 ByTime sample time ___p 1 04 Total number of ByTime samples gt 6 1602 DELTA B 1B 1258Hz The and W down arrow keys move you to the next higher and lower filter frequency The 4 left and right arrow keys move you to the previous and next ByTime sample If auto RT60 is set to Yes the auto select routine will be performed whenever a new filter is selected 11 34 An auto select routine will automatically locate the cursor to be 5 dB below the maximum level The auto select is executed on demand from the check menu and the first time the RT 60 display is selected There is a vertical line for the cursor specifying the beginning of the measurement and a horizontal line drawn at the dB down level Auto select also sets the horizontal zoom so that the whole decay fits on screen 824 Reference Manual 9 29 09 RT60 Check Menu Pressing the Y check key when viewing the RT60 display puts you in the RT60 check menu The check menu is shown below Auto Se lecto The check menu offers the following options RT60 dB Down dB down setting for RT 60 calculation Auto RT60 Setting to enable an auto select of RT60 whenever a new filter is selected e Auto Select Auto Select cursor position e Graph V See page 2 13 for explanation Graph H See page 2 13 for explanation View Back Returns you to the previous display Spatial Avg Views The Spatial Avera
49. End Time then the 824 stops recording an Autostore e L When the level is equal to the End Level 0 5 dB then the 824 stops recording an Autostore L gt When the level is greater than the End Level for End Time then the 824 stops recording an Autostore Input 824 stops recording an Autostore after the logic input line changes to End Logic In state 824 Reference Manual 9 29 09 If set to 0 seconds triggering will repeat forever and the measurement will end when stopped or out of memory If set to 0 samples the measurement will stop after the first event is captured 9 29 09 Time The 824 stops recording an Autostore after Time Count The 824 stops recording an Autostore after End Samples of data have been received End Level This level is used when the End Mode is set to Level L lt L L gt It is the amplitude in dB at which the 824 will stop recording an Autostore record 0 0 255 9 dB End Time The 824 stops recording an Autostore record when the End Time has been satisfied 00 0000 to 99 9975 seconds End Samples The 824 stops recording an Autostore after Samples has been satisfied 0 65535 End Logic In When the End Mode is set to Input the 824 stops recording an Autostore record when the L logic In line changes to End Logic In state Low High optional 11 13 Then Settings
50. Setup Report No Print the settings and their values for the LOG instrument SPL Histogram No Shows 6 Ln values Lmax Lmin and a bargraph of the level distribution Report No Lists Number of Record Exchange Rate Minimum Duration Time Period Mode Start Time Leq Max Peak Overloads Unweighted Peak Duration SEL and Spectrum Intv Report No Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in the short report The Long reports adds the Ln values for the Interval period Hist Report No Leq for each time history period Daily Report No Lists date duration Leq Peak Uwpk Ldn Lmax CNEL and Lmin Print Range Report No You can customize the interval report by choosing the long or short report Lowest Record 00000 Selects the lowest exceedance record to be printed Highest Record 65535 Selects the highest exceedance record to be printed Intv Report No You can customize the interval report by choosing the long or short report Lowest Record 00000 Selects the lowest interval record to be printed Highest Record 65535 Selects the highest interval record to be printed Hist Report No You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time history record to be printed Highest Record 799999 Selects the highest time history recor
51. 1 1 octave band frequencies 16 Hz 16 kHz 11 octaves Filter integrated response lt 0 15 dB for all filters Real time operation lt 0 3 dB error for all filters tested with a swept sinusoidal input Anti aliasing gt 75 dB Summation of output signals lt 1 0 dB 0 4 typical Flat frequency 10 Hz 20 kHz relative response attenuation 0 15 dB Filter type Digital Octave frequency ratio Base 2 824 Reference Manual 9 29 09 AC DC output AC out 1 is flat weighted and follows the gain tip AC out 2 is C weighted with 0 dB gain ring Measurement range Flat is measured to ANSI 51 4 and IEC 60651 standards for SLM linearity 1 3 and 1 1 octave filters are measured to IEC 1260 standard for Class 0 linearity which is 0 3 dB The numbers in the table represent SPL levels with a typical 377B41 microphone that has 44 1 mV Pa sensitivity Measurement Range RTA mode only 0dB Gain 10dB Gain 20db Gain 30dB Gain 40dB Gain 50dB Gain NF Start End Du NF Start End 5 NF Start End NF Start End ds NF Start End bog NF Start End Reng FLAT 32 48 28 80 25 38 8 80 21 33 108 75 2 5 98 65 26 8 88 50 2 0 78 38 1 3 Octave Filters 16 0 2 45 ps 5 5 10s 8 2 2
52. 241023 7 Data Files gt Setups Allocated Total memory including both data and setup register memory Memory Settings also accessed by pressing the V key from the Memory display screen See next page for detailed information on the Delete Last feature Purge All Data Files is also available from the reset menu under the RESET key 3 28 Total Memory 262144 The top portion of the Memory b display shows the same available memory information as in the Memory a dis play In addition the Memory b display shows the number of data files memory number of setup registers allocated and the total amount of memory including that memory allocated for setup registers To modify the Memory settings use the W key to select Memory from the Tools menu then press the D key Delete Last The Delete Last feature will allow the user to delete the very last record stored in memory from any instru ment type To delete the last stored record highlight Delete Last and press the Check key Purge All Data Files Pressing the D or Y key when the Purge All Data Files menu item is highlighted allows you to purge all data files in memory This clears the memory 824 Reference Manual 9 29 09 The default value of this setting is 10 allocated setup registers which uses 5120 bytes of memory The System 824 has ten permanent ID registers These pre def
53. Changing the displayed secondary parameter Step 1 select the secondary parameter to be displayed Leq in this example use the 43 or W keys to highlight the Leq label ldBR 2 Gain 8 Step 2 Press the D or 4 arrow keys to display the val ues of A weighted SEL Lmin Lmax Lpeak val ues Select Peak and press the check Y key Changing the frequency weighting of the displayed Lpeak value Step 1 With the Peak label selected press the or W keys to highlight the Peak weighting SP A 100 Peak NET TUNE Use the D or 4 arrow keys to display the or Flat weighted Lpeak values Changing the amplitude range or input Gain When using the SSA ID as in this example the measurement range is 80 dB unlike the ISM and LOG IDs for which it is 105 dB In order to optimize a particular measurement provisions have been made to select a value of input gain directly from the graphic display The gain can 2 10 824 Reference Manual 9 29 09 also be changed from the Setup Menu as described later in this manual or it can be changed here Step 1 To change the gain Use the or W keys to highlight the Gain as shown below SLI RTA SP A inn BD Le ED EP The gain shifts the dynamic range up or down See page 5 3 Step 2 Use the D or 4 arrow keys to change the input gain Views For each instrument type e g ISM LOG or SSA a unique
54. J 9 5 4700 2n up and 5 down arrow keys move you through each filter The 4 left and D right arrow keys move to the previous and next ByTime sample ByTime Spectrum Check Menu As discussed earlier in order to move between the ByTime spectrum display and the ByTime Graph display you pressed the check key twice toggling between the ByTime Spectrum view and the ByTime Graph view Pressing the check key once when viewing the ByTime spectrum display puts you in the check menu The check menu is shown below __ HuTime ByTime Grapholu Autostore Locate tAVerage Rooms 11 30 824 Reference Manual 9 29 09 The check menu offers the following options ByTime Graph View the time graph of one filter Autostore View the Autostore Leq and Min spectra The Locate menu helps you find the Locate Locate an Autostore ByTime record record you would like to view Next The next Autostore record Prev The previous Autostore record First The first ByTime record Last The last ByTime record Find Finds the specified ByTime record The Spatial Averaging displays and Average Add spectrum to spatial average or view spa menus are covered later in this tial spectra average chapter If 1 3 octave filters are selected the Rooms View NCB and RC Room Criteria for this spec Rooms display gives you the Hearing trum for 1 1 octave filters Threshold
55. S159 166 Reserved settings 5167 ALL RELATIVE LEVEL REFERENCE S174 ALL UNFORMATTED REPORTS x 5175 Reserved setting 8176 ALL PRINTER TYPE x S177 ALL DATA REPORT x S178 SSA LOG R S AND CAL LOG x 8179 ALL SETUP REPORT x S180 LOG RMS HISTOGRAM TABLE x S181 LOG RMS HISTOGRAM TABLE LOW n EST VALUE 5182 LOG RMS HISTOGRAM TABLE HIGH n EST VALUE 5183 LOG RMS HISTOGRAM TABLE RESO x LUTION S184 LOG PEAK II HISTOGRAM TABLE x A 46 824 Reference Manual 9 29 09 S185 LOG PEAK II HISTOGRAM TABLE n LOWEST VALUE S186 LOG PEAK II HISTOGRAM TABLE n HIGHEST VALUE 8187 LOG PEAK II HISTOGRAM TABLE x RESOL S188 LOG PEAK I HISTOGRAM TABLE x S188 RTA RTAf PRINT LIVE SUMMARY OR NO YES EVENT DATA 5189 LOG PEAK I HISTOGRAM TABLE LOW n VALUE 5189 RTA RTAf PRINT LEQ SUMMARY OR YES EVENT DATA 5190 LOG PEAK I HISTOGRAM TABLE HI n VALUE S190 RTA RTAf PRINT MAX SUMMARY OR NO YES EVENT DATA S191 LOG PEAK I HISTOGRAM TABLE x RESOL S191 RTA RTAf PRINT MIN SUMMARY OR NO YES EVENT DATA S192 LOG EXCD REPORT x 8192 RTA EVENT WORKING REPORT NO SHORT LONG ENABLE 193 LOG EXCD REPORT LOWEST RECORD n 5194 LOG EXCD REPORT HIGHEST RECORD n 5195 SSA ISM INTV REPORT x LOG 195 RTA SPATIAL AVERAGE HISTORY NO
56. eo Ree eee 11 6 11 19 End Level ot uod oen eO RR ORO Er Ruso ed 11 13 End Logic In itas iiS UU e eR RO Ue e e ni ee lets 11 13 ote ie ee terere baton eee te tee batte ch OAT RS 11 12 End Samples one etie ente eet edd eee ees 11 13 edi deii 11 12 End Settings Menu eee ehe te t He e PR HE ee d 11 12 End Then e P T 11 14 End Time cue ee dade dci etes 11 13 Exponential Detector Time sessi eren nnne nnns 11 7 Exponential Store Rate isses te e ue OR RERO de eri caine e et eee 11 7 Gam toD Rp bete atte eee ate tee e Mn detis ee CHE reg 11 6 EQ c rete err DF ERE EE Td e tme s 11 21 Linear Detector ieiunus 11 7 DAY iuo ihe nette REL I HR E PEE Eee reste n ERE REIR YE e ES 11 20 Logic Output Ne ed T UI X EIN s UR 11 15 Max oed Neo cree tbi e ree eee is 11 21 measurement times E et i eaten bei 11 22 TRE EE 11 22 Minimum R T 60 i ertet tote a eoe DO ee oh UR fe y Mete Po RE S G 3 Minimum RT 60 value tret ee To eee tee dei ie URS G 3 NOUS meas thue in hn einem 11 16 locua 11 8 Random
57. Calibration Checked gt 1999 11 35 85 gt aaah 113 1dEB Date and time of the last calibration change Offset currently in use to calibrate the levels M M EAT 242 21 56 ffseti d 1 dB 3 22 The Calibration display shows the date and time of the last calibration change and the offset being used to calibrate the levels It also shows the date and time of the last calibration check and the level detected during that check To utilize the calibration tool or modify the Calibration set tings use the amp or W key to select Calibration from the Tools menu then press the key The Calibration menu provides the following settings Check Activates the calibration check level verification process 824 Reference Manual 9 29 09 Clock Timer Change Activates the calibration change adjust process Cal Level Enables the user to enter the sound pressure level generated by the calibrator Calibrator S N Enables the user to record the serial num ber of the calibrator for reference Noise Floor Enables the user to enter a noise floor value Optimum values will depend on the type of measurement being performed For a more detailed description See Entering the Noise Floor Values on page 9 4 To display the time and date or to view the timer settings use the or W key to select Clock Timer from the Tools menu then press the Y key The foll
58. EEPROM Fault 149 Out of Memory 150 Memory was Lost 151 Unimplemented 152 System Locked 153 A D Stack Full 154 A D Over Run 155 Serial Port Framing 156 Serial Port Line Noisy 157 Serial Port Over Run 158 Unknown I O Command 159 Operand 1 Range 160 Operand 2 Range 161 I O Overflow 162 Can t Calibrate 163 Calibration Invalid 164 Analog Calibration Bad often an indication of a faulty EPRM 165 ID is Active 166 ID is in ROM 167 ID is Read Only 168 ID is in a File 169 ID has Changed 170 ID Space Full 171 Purge Required 9 29 09 A 73 172 No Data 173 Not Available 174 Demo Mode 175 Setting Conflict Modem Control Mode All Instruments The modem control mode enables the Model 824 to automatically dial out upon an exceedance or a low memory condition This mode also enables the Model 824 to answer the phone so that instructions can be received The modem must be Hayes TM compatible and set to respond to commands using numeric codes non verboses Modem Mode If the Modem Mode is Yes the Model 824 will dial the Phone on the events selected by the Dial Out Mode defined below Dial Out Mode A 74 None The Model 824 will not dial a computer for any reason Excd The Model 824 will dial a computer to report when an illegal exceedance
59. LOG SSA The Hist Report either enables or disables the printing of the Time history report The history report contains the Leq and optionally one selectable level Lpk I Lpk II Lmax basic measurement parameter for each time history period This setting provides the following two options No The history report will not print Yes The history report will print Menu Layout of SSA Settings The SLM amp RTA Edit Settings menu has 49 configurable items Provided in this section is a table depicting the menu layout of the SLM amp RTA instrument s Settings Menu Submenu Available Settings Items Options Title User customized text entry 9 29 09 Using ID Setting Files 7 45 SLM Detector Weighting Gain Transducer Condnsr Elctret Direct Random Corr No Yes Pk Weighting A C FLT RTA RTA Detector Slow Fast RTA Weighting FLT Bandwidth 1 1 1 3 7 46 824 Reference Manual 9 29 09 9 29 09 Intervals Intv Enable Intv Period Intv Time Sync Intv Save Ln s Intv Auto Stop Intv Threshold 0 255 dB Intv Exchange 3dB 4dB 5dB 6dB Intv Spectrum None Max Min Using ID Setting Files 7 47 7 48 Time Hist Enable History No Yes Hist Period 0 255 default 60 Period Units 1 32s 1 0s 10 0s 60 0s Resolution 0 1db
60. Press the or W arrow keys to highlight the SLM amp RTA SSA item and press the key to select it The last used SLM RTA display appears SL H TFTR SPL Slow dE 14 A i00 BD Ley At this point if you want to view a display other than the one shown press the VIEW key Use the or W keys to highlight the desired display For this example highlight SLM and press the Y key to select it The SLM display of the SLM RTA instrument shown in step 2 will appear The Sound Level Meter with Real Time Spectrum Analyzer is now ready to use To take a sample reading press the STOP key A screen similar to the following appears 51 SPL Slow 43 53 dBA TE Let the instrument continue to take measurements for about one minute Make some noise and watch the results on the graph Press the RUN STOP key to stop the measurement 9 29 09 The screen shows a black box symbol in the upper right hand corner indicating that the instrument is stopped not measurement taking a If you attempt to store data while a measurement is still running a warning will displayed indicating that the measurement must first be stopped NOTE You may want to repeat the pro cess of running a measurement stop ping and storing its data a few times so that you will have several samples of stored data to choose from when trying this ex
61. Pressing the key and selecting Recall File from the Data Files menu allows you to recall that measurement An active data display will be shown When recalling a data file the System 824 will switch to the instrument definitions ID that the data file was stored as SLM amp RTA to Logging if the user was currently using the SLM amp RTA instrument and recalled a Logging data file If the run key is pressed while a recalled data file is active the data 1s reset and the new data is taken using all of the settings that were stored with that data file The data file also contains calibration information that may be different than the current calibration When Run is pressed the recalled calibration is replaced by the latest cur rent calibration Use the SETUP key to access the Setup menu where you can select create and manipulate groups of instrument set tings known as instrument definitions ID The Setup menu presents a list of pre defined IDs marked with a and user defined IDs if previously configured that are available for use To access the Setup menu press the 4 key screen similar to this appears Edit Settings ii EET FSLM amp RTA SSA Tom Guuyu p SLM LOG ISM An ID defines the data that is to be measured for a particular project or type of application The defined project IDs are listed in the Setup menu You can create edit copy and
62. The Environmental noise analyzer option is either present E1 or not EO The memory has 4 options Standard 1 2 megabyte MO 1 megabyte M1 1 5 mega byte M2 and 2 megabyte M3 Example 0 M3 means there is a 1 3 octave filter installed there is no ENV option and the memory is the standard 2 megabytes 1 2 Read Model string 824 824 R1 3 Read Flash Identification hhhh Manf Device Code IF IF 13 13 R1 4 All hhhh options installed in hex R1 5 All Reads out the RTC s real time clock serial number in hexadecimal R1 128 All Read ConfigFlag hh in hex Rl n Test selected bits in Configflag n 129 255 Selected bits in ConfigFlag can be tested If any of the specified bits are set 1 then the response will be Yes otherwise the response is No The following examples show how bits in ConfigFlag can be tested The binary number shown is the binary value of the decimal operand of the command Command Instrument Binary Value ConfigFlag Bits Type Tested R1 129 10000001 0 1 130 10000010 1 9 29 09 11 R1 132 10000100 2 R1 192 11000000 6 R1 170 10101010 1 3 5 NOTE the 7th bit of ConfigFlag cannot be tested Syntax Instrument Description Response Type R2 ALL Current Date and Time ddd ddmmmyyyy hh mm ss R3 ALL Status Run mode Lock Logic In Alarm Archive 0 R3 1 ALL Short status string
63. bit flags Add 1 to x to automatically reset histories at completion of transfer Add 2 to x to inhibit the pause just before sending OverAll data the pause provides for cohesive data Add 4 to x to begin where last download ended always starts at the beginning of stored data if not set Add 8 to x to disable waiting for acknowledgment at the end of each block transfer used with error checking modems 1 MNP 4 or V 42 Add 16 to enable the Xmodem download at 57 6 kilobaud Comm Port 1 ONLY The resulting binary file structure is undocumented and unsupported The advantages of the binary features can be obtained by utilizing Larson Davis soft ware turnkey application data translators or function library support is available X X CANCel transfer mode 2 in a row ASCII CAN or CHR 24 gt a b Read 824 s memory from address a and bank b A 78 824 Reference Manual 9 29 09 Read T H Buffer This command is used to create an SPL vs Time plot that is time cohesive Resolution is by default 1 dB with one byte sample being sent Each byte has 32 added to it to avoid confusion with ASCII control codes subtract 32 to use Only the samples taken since the last read are sent up to the buffer size of 128 samples The time of day is appended to the end of the string to permit time stamping of the SPL graph A delimiter byte ASCII 212 in decimal which is the letter with 128 added
64. p Fixed Average The averaging process is over a fixed time period The equation for it is The sound pressure is squared and averaged over a fixed time period Unlike the moving average the sound pressures in all time intervals are equally weighted The logarithmic form of sound pressure It is also expressed by attachment of the word decibel to the number The logarithm is taken ofthe ratio of the actual sound pressure to a reference sound pressure which is 20 MicroPascals Pa There are various descriptors attached to this level depending on how the actual sound pressure is processed in the meter Instantaneous The time varying reading on a meter face on in a meter output due to changes in the sound pressure The reading will depend on the time weighting applied The fundamental relationship between the two is logarithmic rms 20 L 200g Prms p 10 0 where is the reference sound pressure of 20 uPa The square of the sound pressure is a power like quantity that can be expressed in the original form of the level definition 2 L 10 Lp EZ polo 824 Reference Manual 9 29 09 Sound Pressure Level can be converted to sound pressure as follows If the sound pressure is 1 Pascal then the sound pressure level is pos 201og 20106150000 20 4 699 94 048 20 10 Pa 2010 5 10 Sound Power W Sound Power Level PWL Ly 9 29 09 Calibrators oft
65. s Peak I Exceedance Level was surpassed Peak II Exceedances Peak II Exceedances shows how many times during this interval that the instrument s Peak II Exceedance Level was surpassed Overloads This shows how many overloads occurred during this interval The Interval e display consists of three major components Display label nterval Number Ln Centiles Readings The Interval e display is shown below LOG instrument only System 824 Views 5 49 Display label le B 4 Interval Number gt Liat 8 32 9 4 i uH pr 11 3 50 0 1 2 18 2 7 Lan n J 8 az z Ln Centiles Readings The following explains each of the display s components Display label This shows the current display for example Interval e Interval Number The Interval Number display shows each measurement interval in the order that it occurred The Interval Number indicates the order of the displayed interval in relation to the other interval records Ln Centiles Readings Shows the six Ln Centiles readings for this interval Intervals f Display The Interval f display consists of seven major components Display label Interval Number Interval Date Time Average Windspeed Maximum Windspeed Direction of Maximum Windspeed Interval Duration The Interval f display is shown below LOG instrument only 5 50 824 Reference Manual 9 29 09 Display
66. sese 7 37 Intv Period LOG SSA ect eq m aate 7 37 Intv Time Sync LOG SSA 7 37 Intv Save Ln s LOG 585 1 2 2 2 00 00 1 00000000 00000000000000000003 7 38 Intv Auto Stop LOG 7 38 Intv Threshold LOG SSA 7 39 84 iicet etes rines 7 39 Intv Spectrum SSA Only 4e ee ete 7 39 Logging SLM Exceedance History Settings sse 7 40 Triggering LOG eie o e 7 40 Excd Enable LOG essere 7 40 Min Duration LOG esee ete eene 7 40 Exed Time iui eed ad E ed etes 7 41 iii vii 824 Reference Manual TH Period 706 re eres 7 41 Exed Tigger LOG stees mr E d Heo ed 7 41 Time LOG eie ertet eripe e ers 7 41 Timed Excd Period 2 2 2 020000000000000000000000000000000000004 7 41 Daily Enable 7 42 Daily LOG isses eei e EUR Re 7 42 Logging SLM Define Report Settings ss sssesssssseesstsersteresreresersessesresessese 7 42 Data Report LOG SS4A cssc dee e ee ee tede 7 43 Setup Report EOG SSA siente cete epe 7 43 SPL Histogram LOG 7 44 Pk 1 Histogram L
67. 070 Selects the lowest Peak2 histogram level to be printed Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 5 0 Selects the Peak2 histogram resolution Long Report This template shows the default settings for the All Long Report The Long Report prints all of the reports Those reports with a long version are printed in the long form After selecting the template you can modify it as explained in Printing a Custom Report on page 8 23 Long Report Template SSA instrument Report Settings Lower Level Report Settings Description Unformatted No A dump of all Read Query and Interval remote commands Multiple values are comma delimited Data Report Yes This shows general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Setup Report Yes Print the settings and their values for the SSA instrument 9 29 09 Printing a Report 8 17 Long Report Template SSA instrument Intv Report Long Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in the short report The Long reports adds the Ln values and Spectral LNs for the Interval period Hist Report Yes Leq for each time history period Print Range Intv Report Long You can customize the interval report by choosing the lo
68. 1 824 Reference Manual 9 29 09 Computer 82440123 11111111 824 sends Ready 9 29 09 sends Step 5 Step 6 Alarm 2 Exceedance 4 Low Memory More than one of these can be set at a time in which case x is the sum of all set flags The Model 824 awaits a response code which should be 824A0123 11111111 enter where 0123 1s the Model 824 s serial number and 11111111 is the Lock Combination setting 28 which is required whether or not the Model 824 is currently locked If the response 18 incorrect the announcement is resent Four chances are given to respond correctly 3 cr sequence will cause the Model 824 to hang up When a correct response is received the Model 824 indicates it 1s ready to send data when requested with 824 Ready enter Each line ends with a CR and line feed lt LF gt Unsupported Miscellaneous Commands NOTE Use of these commands is up to the discretion of the programmer they are considered undocumented unsupported Larson Davis makes warranties for their proper operation and is unable to support them with fur ther documentation or through customer support They are used by proprietary Larson Davis software and are docu mented here on an as is basis for those who may desire to explore unaided these advanced features The operation of these commands is subject to change without notice of any kind 16 XMODEM binary data dump x
69. 1 0db TH Setup Activates a set of 3 displays used to configure what time history data will be stored See the section Advanced Time History LOG SSA on page 7 35 Marker Text Marker 1 Aircraft Marker 2 Automobile Marker 3 Truck Marker 4 Train Marker 5 Animal 824 Reference Manual 9 29 09 9 29 09 Ln Enable No Yes Start Level 0 99dB default 15dB Ln 1 Percent Selectable default 1 6796 Ln 2 Percent Selectable default 8 33 Ln 3 Percent Selectable default 33 33 Ln 4 Percent Selectable default 50 Ln 5 Percent Selectable default 66 67 Ln 6 Percent Selectable default 90 Spectral LN None Overall Interval Triggering SPLExcdLvl1 0 255 dB default 115dB SPL Lvl 2 0 255 dB default 120dB Pk 1 Lvl 0 255 dB default 140dB Pk 2 Lvl 0 255 dB default 140dB Hysteresis 0 9 dB default 2dB Advanced See Advanced Menu Layout on page 7 56 Using ID Setting Files 7 49 Menu Layout of Integrating SLM ISM Settings 7 50 The Integrating SLM ISM Edit Settings menu has 16 configurable items Provided in this section is a table depicting the menu layout of the ISM instrument s Standard Settings ISM Setting Menu Submenu Available Settings Items Options Title User customized text entry 824 Reference Manual 9 29 09 SLM
70. 1 nnnnn R32 LOG RMS Exceedances 2 nnnnn R33 LOG Peak Exceedances nnnnn R34 LOG UWPk Exceedances nnnnn R35 ALL Overloads nnnnn R36 ALL Number of PAUSES nnnnn A 14 824 Reference Manual 9 29 09 R37 ALL PAUSE Time OFF Time not inc hhhhh mm ss R38 LOG SSA Ln 1 nnn n dB R39 LOG SSA Ln 2 nnn n dB R40 LOG SSA Ln 3 nnn n dB R41 LOG SSA Ln 4 nnn n dB R42 LOG SSA Ln5 nnn n dB R43 LOG SSA Ln 6 nnn n dB R44 LOG Overall Dose nnnnn n R45 SSA ISM Current Dose nnnnn n R46 LOG Overall Projected Dose nnnnn n96 R47 SSA ISM Current Projected Dose nnnnn n96 LOG R54 ALL Last Level Relative to REFLVL nnn n R55 LOG Display Histogram Selected ccc R 56 LOG Display Total Counts in Ln Table nnnnnk R57 LOG Overall Leq nnn n dB 58 LOG Daily Leq nnn n dB R59 LOG Current Hourly Leq nnn n dB R60 h LOG Hourly Leq h 0 23 nnn n dB R61 h LOG Hourly Leq partial indicator h 0 23 nnn n dB R62 LOG Overall LDN nnn n dB R63 LOG Daily LDN nnn n dB R64 LOG Hourly LDN nnn n dB R65 LOG Overall CNEL nnn n dB R66 LOG Daily CNEL nnn n dB 9 29 09 A 15 R67 LOG Hourly CNEL nnn n dB R68 LOG Total EXCD Leq nnn n dB R69 LOG Total EXCD Time hhhhh mm ss s NOTE The exceedance Leq R68 and exceedance time R69 include data from qualified events that
71. 110 Selects the lowest Peak histogram level to be printed Highest Level 160 Selects the highest Peak histogram level to be printed Resolution 5 0 Selects the Peak1 histogram resolution Pk 2 Histogram Yes You can customize the Peak2 Histogram report by choosing the long or short report Lowest Level 070 Selects the lowest Peak2 histogram level to be printed 9 29 09 Printing a Report 8 15 Short Report Template SSA instrument Histograms Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 5 0 Selects the Peak2 histogram resolution Short Report Template LOG instrument Lower Level Report Settings Report Settings Description Unformatted No A dump of all Read Query and Interval remote commands Multiple values are comma delimited Data Report Yes This shows general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Log Report Yes The run stop log and with the date and time of each run stop Setup Report Yes Print the settings and their values for the LOG instrument SPL Histogram Yes The 6 Ln values Lmax Lmin and a bargraph of the level distribution Intv Report Short Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in the short report The Long reports adds the Ln values for the Interval period
72. 28Jun15i slmdl ISM on which the data was taken The file name can be changed to any name 28Junl5s slmdl SSA that you choose e 28Junl5l slmdl LOG 28Junl5r slmdl 28Jun15f slmdl FFT 28Junl5a slmdl AUD e 28Junl5t slmdl TAL The translated files will have either a csv extension or a txt extension depending on the choice made in the download window Translating Data from a Downloaded Binary File Selecting Translate View from the View Menu or pressing the Translate button on the tool bar will display the Transla tion View 9 29 09 Using the 824 Utility Software 10 25 You use the Translate view to select a downloaded file with the file extension slmdl to translate and view the desired records from the file on the screen or to print the desired records from the file 824 Utility Biel Es File View Setups Data Help 4 Eile For Help press F1 2 The left portion of Translate window functions as a Win dows file tree Select the folder that contains the down loaded measurement files that you wish to translate 824 Utility File View Setups Data Help Haaga mmr lel 2s ICWHnternet Connection Wize a 1 Internet Mail and News 3 IrfanView Locate the folder that contains the Kodak Digital Science downloaded file you wish to translate E c Utility In this case we have found the down 02Jul16r_001 imal
73. 5 volts through a 10 000 ohm current limiting resistor to pin 7 of the control connector 5 volts is the asserted state 824 Reference Manual 9 29 09 Logging SLM TWA Settings Use the and W keys to move from one setting to the next Then use the key to change the selected setting The key is used to return to previous menus Ovil Exchange LOG This setting affects the System 824 5 primary or overall memory buffer 9 29 09 The Time Weighted Average settings are available to the Logging SLM LOG instrument In a few cases the ISM instrument also provides access to a few of the TWA settings The following table shows the TWA settings as found in the LOG instrument Each setting 1s later described in greater detail Menu Items Available Settings Options Ovll Exchange 3dB 5dB 6dB Ovll Threshold 0 255 dB Criterion 0 255 dB Criterion Time 0 99 hours Crnt Exchange 3dB 4dB 5dB 6dB Crnt Threshold 0 255 dB Crnt Criterion 0 255 dB Using ID Setting Files The Overall Exchange rate setting sets the exchange rate sometimes called the doubling rate that is used to calculate the overall TWA The exchange rate reflects the relationship between the permitted exposure levels and the exposure duration Selecting an exchange rate of 5dB for example means that 5dB may be added to the permissible 7 17 The formulas for TWA can be found in Integrat
74. Detector Slow Fast Impl Weighting A C FLT Range Normal Low High Transducer Condnsr Elctret Direct Random Corr Pk Weighting Crnt Exchange 3dB 4dB 5dB 6dB Crnt Threshold 0 255 dB Advanced See Advanced Menu Layout on page 7 56 Using ID Setting Files 7 51 Menu Layout of Logging SLM Settings The Logging SLM LOG Edit Settings menu has 66 configurable items Provided in this section is a table depicting the menu layout of the LOG instrument s Standard Settings LOG Settings Menu Items Submenu Available Settings Options Title User customized text entry SLM Detector Slow Fast Impl Weighting A C FLT Range Normal Low High Transducer Condnsr Elctret Direct Random Corr Pk Weighting No 7 52 824 Reference Manual 9 29 09 TWA Ovll Exchange 3dB 4dB 5dB 6dB Ovll Threshold 0 255 dB default 80dB Criterion 0 255 dB default 90dB Criterion Time 0 99 hours default 8 hours Crnt Exchange 3dB 4dB 5dB 6dB Crnt Threshold 0 255 dB default 80dB Crnt Criterion 0 255 dB default 90dB Ln Start Level 0 99dB default 15dB Ln 1 Percent Selectable default 1 67 Ln 2 Percent Selectable default 8 33 Ln 3 Percent Selectable default 33 33 Ln 4 Percent Selectable default 50 Ln 5
75. Display label Leq Reading SEL Reading Max Reading Date Time Elapsed Time The PassBy display is shown below Display label FP azzzzEu 1999HuaiB8 17 02 49 lt Date Time Duration HE 4 4 Elapsed Time Leq Reading gt oq OY 3dBH SEL Reading SEL 14 3 Max Reading eax 106 The following explains each of the display s components Display label This shows the current display for example PassBy L eq Reading This is the Leq for the Passby event including all energy between the 10dB down points centered around the maximum SEL Reading This display shows the total sound energy of a measurement compressed into one second Max Reading This display shows the maximum sound pressure level that occurred during the passby Date Time This displays the date and time of the passby 5 68 824 Reference Manual 9 29 09 NOTE The Passby triggering system can be used to create an exceedance record of each passby set Excd Trigger to Passby Wind Tach The and W arrow keys can be used to cycle between the Metrics PassBy and Wind Tach views Wind a Display Elapsed Time This shows the elapsed time between the 10dB down points prior to and following the maximum level measured The Wind Tach View has three displays which can be accessed by simply selecting Wind Tach with the Y Check key from with
76. Flat and with all detectors slow fast and impulse simultaneously Includes time history interval history exceedance history daily history Ln percentiles statistical data exposure and dual SLM current and overall Wind and Tach data with external transducers RTA High speed spectral data gathering of up to 400 spectra per second using Autostore function Spatial averaging of any number of spectra Flexible triggering for data acquisition Performs RT60 RC NCB HTL Exponential and linear detectors FFT 400 line FFT with Hanning Flat Top or Rectangular window snapshot data storage display zoom with a factor of 2 4 or 8 Count averaging 1 to 16384 measures THD units be user defined AUD Audiometer testing for level frequency linearity THD pulse crosstalk frequency modulation narrow band broadband and speech noise TAL Performs complex tonality calculations required by DIN 45681 Measures the frequency of a dominant tone Fr the level of the tone Lr the bandwidth of the tonal group F the level of the group Lg and difference of the two levels Lr Lg SLM measures LA Lomax LAFTMS5 Los and Lceq LAeq A snapshot history is provided to store and display data from the various modes This chapter will discuss how to select an ID in addition to providing an explanation of the features of the currently avai
77. History Records Histories are records of stored data based on time or a particular event One record is available at a time The current record number is selected by using the Advance Backup and Find commands see below or the Setting S211 through 217 The various histories of the System 824 are each accessed in a similar fashion The Find command is the primary method of locating a history record for random nonsequential access For example to find the one hundred twenty fifth Exceedance record you send the command F125 1 lt cr gt where the 1 specifies that it is an Exceedance record to be found as defined in the history number column below The Advance and Backup commands are generally used next They extract data after the initial find command The Find command takes longer to execute as the record number increases in size therefore for sequential data extraction locate the first desired record with the Find command and then use the Advance command The relative_rec option can be used to retrieve data forward or backward from the current record number without changing that record number it is a signed 8 bit value i e 1 to 127 is positive 1 to 127 while 128 to 255 is 128 to 1 respectively Refer to settings 211 through 217 to query the current record number Setting these to a desired record A 54 824 Reference Manual 9 29 09 number is an alternate form of the Find command Brackets in
78. Intv Spectrum SSA only 9 29 09 Intv Threshold sets the threshold for computing the interval time weighted average TWA As per the requirements of various regulatory agencies only those sound levels which are above a certain threshold level are used when computing the TWA Accordingly this setting can take on any integral value within the following range 0 to 255 dB For hearing conservation measurements set the threshold to 80dB For most community noise measurements set the threshold to OdB The Exchange sets the exchange rate sometimes called the doubling rate that is used to calculate the interval TWA The exchange rate reflects the relationship between the permitted exposure levels and the exposure duration Selecting an exchange rate of 5dB for example means that 5dB may be added to the permissible exposure level every time the exposure duration is cut in half This setting provides the following four options 3dB The 3dB default option is the most com monly used and results in the Leq time weighted aver age which is used in Europe and for measurements that comply with U S Environmental Protection Agency EPA regulations 4dB The 4dB option results in Lpop time weighted average which is used for measurements that comply with U S Department of Defense DOD regulations SdB The 5dB option results in the time weighted average which is used for measurements that comply wi
79. It is measured in meters per second It should not be confused with sound or particle velocity which relates to the physical motion of the medium itself c 20 05 degC 273 m sec c 49 03 degF 460 ft sec The amplitude of sound or vibration at various frequencies It is given by a set of numbers that describe the amplitude at each frequency or band of frequencies It is often prefixed with a descriptor that identifies it such as sound pressure spectrum It is generally expressed as a spectrum level The A weighted sound level below which the sound produces little or no Noise Dose accumulation and may be disregarded It is used for hearing damage risk assessment Standard ANSI 51 25 It is the level of a constant sound over the Criterion Duration that would expose a person to the same Noise Dose as the actual unsteady sound over the same period If the Exchange Rate is 3 dB then the TWA is equal to the Leg where T T gt T and is the Exchange Rate Factor It is used for hearing damage risk assessment Standard ANSI 512 19 824 Reference Manual 9 29 09 Time Weighting Vibration Wavelength Wavenumber k 9 29 09 T B 1 L K wage Kogyo zj 4 The response speed of the detector in a sound level meter There are several speeds used Slow The time constant is 1 second 1000 ms This 18 the slowest and is commonly used in environmental noise measurements Fast The time constant is 1
80. L 33 33 0 dBA L 50 00 0 dBA L 66 67 0 dBA L 90 00 0 dBA y biNssasumss 14 i E i Ready mj 9 29 09 Using the 824 Utility Software 10 31 Additional Features Once the data is in the spread sheet program it can be manip ulated stored and graphed using the standard spreadsheet functions You can also export and or save the translated data to a text file by selecting the Export Data menu item from the File menu 824 Utility File View Setups Data Help Store Histograms for Overall and Interval Data One of the features of the 824 Utility software is the ability to store histograms in both the LOG and SSA virtual instru ments for overall interval and daily data LOG only ill Es e FFT FFT These settings can only be made from the 824 Utility software 10 32 Eme AAA 4 System ssa SLMSRT Sound Level Meter Real Time Analyzer Settings e 15 SLM 8 tos Logging 19 demo ROOMS RTEDA IV Enable Interval History Bp RT60 B Te TALARM Interval Period Threshold Exchange Rate Spectra 195 carpente For Help press F1 Ir Timer SLM RTA Ln Time History Intervars 1 mer l Advanced SSA Interval History for oo o dB Enable Interval Time Synchronization Save Ln s as part of interval records j
81. LOG and SSA Interval Settings on page 7 36 To measure a single interval set Interval Autostop Intv Auto Stop to On as described in the section Intv Auto Stop LOG SSA on page 7 38 To measure and store data over a series of equal time intervals set Interval Autostop Intv Auto Stop to Off The interval time can be set from 00 00 01 hr min sec to 99 59 59 in steps of 1 second The Clock Timer Mode is used when it is desired that the measurement begin at a preset date and time This can initiate either single interval measurement or a sequence depending upon whether the Interval Auto Stop is set to On or Off respectively Setup the measurement using the Clock Timer Menu which is accessed pressing the key using the A or V keys to highlight Clock Timer and pressing the key For details on the use of this menu see the section Clock Timer on page 3 23 824 Reference Manual 9 29 09 Measuring using User Selectable Thresholds The System 824 can be setup to measure data associated with Exceedance Events defined as instances where the sound pressure level exceeds a user selected threshold For a detailed description of setting up the System 824 to measure Exceedance Events see the section Logging SLM Exceedance History Settings on page 7 40 9 29 09 Performing a Sound Level Measurement 9 17 9 18 824 Reference Manual 9 29 09 824 Utility Installation Using the 824 Utility Softw
82. SSA Jeren i eee e ee Hee eec es 33 Mode Commands datiuo bee initaa a a Bernd esd tetas 9 Modem Control Ere C tee eh nec de 74 Modem Mod ca uie ottenuto OR Ue ENDE eU aes 74 Numeric Settings uer RO RE e e e eee tei A 35 Operation Notes oes o E SEES E ERR ESO e A 81 Option Settings ie ere e en E ES Es 33 Other Read Commands Re tete at ee iret ER A 28 Print Commands 5 terere e ede iere 69 Model 831 Technical Reference Manual Index Querying Settings i ka A E ER ERE eG P RHRGRS 31 Read Commands 2 2 ud etie s URP OH eed A 10 RS 232 interface en eaters Pe RUE AFER HL EC EUER 1 RTA Settings Commands eee Hec ter I a e EO RU et ERR 51 Run Log 225 E REL 65 Setting Commands eeu Rape 30 Setting List EE A 37 Tailored e Met Ree ero at Ped aoa mane el erates 45 ir RE i EE EUER RU RE A 36 Time Histoty Variables darrers sc ee e OE PHI cos OPEN ERO EUROPAS 67 Types of RH EUER Te 55 Unsupported Misc Commands nnn 78 PP
83. The window must be in Hanning mode after an overall reset If not Available only in Hanning Window is shown The fundamental must be above the 4 bin or 10 Hz whichever 15 higher In the case where the fundamental frequency is near the 5 bin and it s skirt extends into some or all of the first four bins the fundamental energy sum calculation will include only the 3 and or 4 bins but not the 1 or 2 bin In any case the noise energy sum calculation will never include the first four bins The fundamental must be higher than any of the first four bins There must not be excessive DC or near DC levels THD n must be at least 10 dB below the fundamental level There must be an identifiable tone The fundamental frequency will be displayed whether there 1s an identifiable tone or not faharmonic is less than 10 dB above the noise floor the level of the harmonic is marked with an asterisk The noise floor is calculated as the maximum of the minimum in the two adjacent valleys If one of the harmonic s side bands is higher than the harmonic then the harmonic is marked with an asterisk Pressing the Check key while in the THD display puts you in the check menu The check menu is shown below View E Bandwidth Lz ak1 The check menu offers the following options e View FFT Takes you back to the FFT display 824 Reference Manual 9 29 09 The bandwidth for each line is the B
84. These will appear as shown below E Bookmark L Table of Contents introduction Overview L Front Panel Keys their Functions and Menus Quick Start System 824 Virtual Instruments 8 1 System 824 Views Using ID Setting Files L Printing a Report Performing a Sound Level Measurement Using the 824 Utility Software L RTA optional FFT Optional AUD Optional Serial Port Interface Remote Control L Integrated Level Calculations Technical Specifications amp Glossary 3 Memory Usage C SLM Testing to IEC61672 1 Miscellaneous Information Warranty Customer Satisfaction L3 Index N Bookmarks Thumbnails L 2 n 5 e o zi Ue a In the unexpanded view bookmarks lists the names and page numbers of chapters and appendixes in order of appearance as well as the Table of Contents and the Index Closing Bookmarks To close bookmarks simply left click the tab once more Expanding Bookmarks For any entry if there is a within the rectangle to the left there are sub entries which can be displayed upon expanding the tree by clicking the rectangle For example clicking the to the left of any chapter will expand it into major headings and by clicking all the symbols the complete tree for that chapter will be shown In the following figure we can see the entry System 824 Vi
85. YES REPORT ENABLE 9 29 09 A 47 8196 SSA ISM INTV REPORT LOWEST RECORD n LOG 8197 SSA ISM INTV REPORT HIGHEST RECORD n LOG 8198 LOG HIST REPORT x 8199 LOG HIST REPORT LOWEST RECORD n 5199 EVENT REPORT LOW 0 65535 EST RECORD 5200 LOG HIST REPORT HIGHEST RECORD n S200 RTA EVENT BYTIME REPORT HIGH EST RECORD S201 LOG DAILY NOISE REPORT x S201 RTA TEMPORARY NOTE FIELD FOR 0 65535 SPATIAL AVERAGE 5202 ALL CALIBRATION MODE Off Check Change Chk NF 5203 ALL UNLOCK PASSWORD S204 ALL SETUP FILENAME 5205 ALL ENABLE ERROR CHECKING I O Error Checking I O The error checking I O protocol verifies that commands and data are transferred without errors A 48 To enable error checking the command or 5205 1 command is used To disable error checking two CR characters in a row may be sent if not in the Modem Mode or the S205 OF command is sent 824 Reference Manual 9 29 09 The F is the check character for the S205 0 command A detailed description of the protocol 15 available from Larson Davis and the latest revisions of software utilize the protocol S206 Reserved setting 207 ALL NOISE FLOOR LEVEL This setting is set to the noise floor of the instrument so that it can properly indicate Near Noise Floor messages when within 10d
86. and RTA optional 11 25 Min Use the amp up and amp down arrow keys to highlight the desired display Autostore Press the check key to view the Leq display Leq The autostore Leq display shows a bin by bin equivalent level of all samples while the Autostore is triggered Autostore occurrence date and time Leg 09121999 46 54 40 p Display label RStore Record number Filter level in d3 1 gt 19 Bandwidth 1 1 or 1 3 oct Selected filter frequency 6235 Autostore duration Number of autostore records To move to the next Autostore display press the check key and then the D right arrow key 11 26 824 Reference Manual 9 29 09 Max The Autostore Max display shows the maximum level obtained by each filter and the broadband maximum level of all samples while the Autostore is triggered Autostore occurrence date and time p gt pana aa 6 54 40 Display label Record number total records Store Filter level in dB 29 Selected filter frequency _ gt Autostore duration Number of autostore records Min The Autostore Min display shows the minimum level obtained by each filter and the broadband minimum level of all samples while the Autostore is triggered Autostore occurre
87. and 5 arrow keys to highlight Set tings then press the Y Check key or the ip arrow key A menu similar to the following appears Intervals Use the and 5 arrow keys to highlight SLM then press the Check key or the Ip arrow key A menu similar to the following appears rS Low1ll Height ing 1 Gain 6 Detector Usethe 43 and 5 arrow keys to highlight Weighting then press the Check key or the arrow key A menu similar to the following appears n 1 Range DHormall Highlight the desired weighting and press the Check key 7 61 SLM Check Menu Options SSA and LOG The Check menus Controls and SLM display check menus for the SSA and LOG Settings items correspond to those instruments are identical The following describes the Check described earlier in the Settings Menu setting descriptions section of this chapter Menu Items Purpose Mark Puts a marker in the time history Settings Modifies the SLM settings for the selected instrument Graph Changes the scaling of the instrument s SLM history graph Controls Modifies the Control menu for the selected instrument The following screen appears when accessing the Check menu from the SLM view Controls gt Mark Display Pressing the right D arrow key when Mark is highlighted puts you in the Mark display The followi
88. lower value of sensitivity in order to perform a measurement within the linearity range of the instrument 9 29 09 Performing a Sound Level Measurement 9 13 Overload and Under Range Conditions Overload Condition Reset Under Range Condition NOTE The noise level corresponding to the microphone being used must have been entered by the user as described in section Entering the Noise Floor Values on page 9 4 in order for this feature to function correctly 9 14 When the input signal is too high the electronics will overload This is indicated by a flashing OVLD text message as well as a flashing OL for overload in the upper right corner of the display as shown below This text message will continue as long as the overload conditions continues but it will disappear when the input level drops below the overload level However the flashing OL display will continue to appear in the same position as shown below This indicates that the data measured may not be accurate due to the overloaded condition which occurred during the measurement interval Press the key to reset the measurement This function is described in greater detail in the section Reset Key on page 3 9 The reset facility clears an overload indication and there is no delay time between the operation of the reset facility and the re initiation of a measurement When the sound level being measured is within 10 dB of the
89. of 1 2 78 55 31 5 43 08 821 35 s 5 108 8 f 2 5 9 4 2 8 of 4 2 55 63 0 4 40 Ds 8 0 33 8 85 f 1 2 108 85 f 0 22 98 75 7 5 94 B 78 6 125 2 4 28 88 2 27 8 olf 3 2 108 sof 2 8 sof 9 88 745 8 78 70 250 3 3 pm afs 2 8 5 5 108 5 98 siao 8 s sof 9 8 78 70 500 2 33 128 95 4 25 8 3 f 3 5 18 sfa B o 85 f 10 6 8 82 10 s 78 70 1000 10 32 128 9 f 2 20 8 5 108 83 f 5 B 98 85 f 10 6 8 82 10 s 78 70 2000 15 32 128 96 6 2 8 of 2 5 108 Bf 5 B o 8 8 sof 8 8 78 70 4000 14 2 18 96 7 20 8 sio 5 108 2 B 98 s 8 ss nis 8 78 70 3000 14 32 128 9 7 2 8 of 5 108 oo B 98 8 f 2 2 s 76 3 B 78 6 16000 15 36 28 25 s 93 f 2 5 108 38f 1 5 98 zlo 5 73 1 8 78 60 1 1 Octave Filters 16 0 2 50 08 792 40 8 30 108 78 2 30 33 28 78 50 31 5 3 48 08 80 f 1 40 8 78 1 28 18 80 2 30 9 os f 4 27 alfa 28 78 50 63 0 4 45 08 8 f 0 4 8 7 23 18 sof 0 9 61 7 20 68 7 2 78 55 125 2 45 ps 83 f 2 o 8 86 f 3 3 108 72 23 98 7 9 2 als B 78 6 250 3 42 08 8 3 30 8 88 f 3 20 108 ssf 4 20 98 7 10 B 8 7 9 B 78 6 500 12 38 128 909 4 30 8 20 108 ssf 4 985 80 f 10 8 amp 8 77 10 B 78 65 1000 10 7 28 O1ff 2 25 3 3 4 20 18 ssf 5 8 985 80 f 10 88 77 10 B 78 65 2000 15 37 128 91 25 8 B3 2 20 ms ssf 5 8 9 sof 8 B s 5 5 B 78 6 400 f4 37 18 9 7 25 893 fo 20 108 ssf 2 is 95 sof 6 B 6 B 78 65 8000 14 35 2R 9 7 25 93 1 20 ms s 8 8 sof 2 7 714 3 B 78 60 16000
90. selected for Leq see above and a second Lpeak level cor responding to one of the two alternative choices of fre quency weighting e 1 6 values with 0 1 dB resolution based on user selected percentages with 0 1 resolution Date Time and Duration of Interval Average and maximum wind conditions using external windspeed direction transducers The 824 can log exceedance events based on sound levels that go over a predefined threshold It can also be triggered by an event which raises the level by 10 dB This is called a Passby event The System 824 Ly Centiles feature provides a set of six percentile values to be measured and shown in the Ly Centiles display Using these six settings you can select any six percentile values For example setting one of the six settings to 10 5 would show the SPL that has been exceeded 10 5 of the time during the time of overall measurement These settings can each take on any value within the following range 01 to 99 99 Ln b Centiles Lia En 82 87 B4 z1 21 7 824 Reference Manual 9 29 09 Sound Exposure Exposure a Dose Proj Dose 34E SEL Bt The System 824 lets you set the criteria level and criterion time for Dosimetry measurements 100 dose occurs if a person is exposed to a constant sound field with a SPL equal to the criterion level for the criterion time or full dose hours The criterion level setting can take on any
91. sse 6 3 SSA Measuring Ranges cose peter SH Pent 6 4 EN Percentiles Spectral cx endet 6 5 AC DC Output iv eher eR nie ee 6 5 bogging SDEM za iofra oet acie dtt mete Ned 6 7 Time History conrear ee cte te e e e ERE ADR SE 6 7 Interval History icto iac iR RI ce RO 6 7 Ex eedanees 6 8 EN Petcentiles Broadband 5 e ps 6 8 Sound Exposure ius eese ete eee ee teens eee 6 9 E 6 9 LOG and ISM Measuring Ranges 6 9 Chapter7 Using ID Setting Files 7 1 Recalling ID Setting i E EAE eene 7 1 Customizing ooh ee 7 2 Settings Example SLM amp RTA 55 00 4 1 0 0000400000000 000000000009 7 2 Settings Descriptions eee eee e eed eee n ee eiie 7 4 iii v 824 Reference Manual Common SLM Settings vci RH HR HRS 7 5 Title Setting SSA LOG ISM csicsas 7 5 Detector Setting SSA LOG 15 7 5 Weighting Setting SSA LOG ISM ccccccccscsccssscssescssescneeseneeseeeseneeeeneesens 7 6 Gain Setting SSA AE P E EEE T 7 6 Range Setting LOG 15 n RE E SS 7 7 Transducer Setting SSA LOG ISM sse 7 8 Random Incidence Microphone Correction Available to all Instrument types st code N E edente diss E 7 8 Pk Weighting SSA LOG 7 9 RTA Detector Setting SSA ea a n a a E R E 7 9 RTA Weighting
92. the possible file types that can be displayed This allows you to select only the files you want for download You can also select ALL lt binary gt which will download all the files in the 824 simultaneously for translation at a later date If you are selecting a specific file type such as SSA the measure ment list box will show only SSA files The first entry in the Measurement list box displays informa tion about the active measurement currently in the 824 Fol lowing the active measurement is a list of all other Data Files stored in the 824 The measurements are identified the same way the setups were identified in the Setup List Box in the setup portion of the 824 Utility manual The name of the ID is listed in the right hand col umn For the permanent ID s this will be the Larson nr Davis instrument type For a user defined ID this ci can be anything that the user defines PT a Test Set 55 2 Test Set The three letter Larson Davis assigned name is 3 Test Set listed in the blue Ovals This indicates the type of ssa 4 Test Set instrument ID for which the setup was created 10 18 The file number as stored in the 824 Specifying a Destination File ert 5 HFT 9 Logging L eae 7 ROOMS You can tell the 824 Utility program where you want the downloaded measurements to be stored From the Download 824 Reference Manual 9 29 09 window p
93. 095 Selects the highest SPL histogram level to be printed Resolution 5 0 Selects the SPL histogram resolution Pk 1 Histogram No You can customize the Peak1 Histogram report by choosing the long or short report Lowest Level 110 Selects the lowest Peak histogram level to be printed Highest Level 160 Selects the highest Peak1 histogram level to be printed Resolution 5 0 Selects the Peak1 histogram resolution Pk 2 Histogram No You can customize the Peak2 Histogram report by choosing the long or short report Lowest Level 070 Selects the lowest Peak2 histogram level to be printed Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 5 0 Selects the Peak2 histogram resolution None Enabled Report LOG instrument Report Settings Lower Level Report Settings Description Unformatted No A dump of all Read Query and Interval remote commands Multiple values are comma delimited Data Report No This shows general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Log Report No The run stop log and with the date and time of each run stop Setup Report No Print the settings and their values for the LOG instrument SPL HIstogram No The 6 Ln values Lmax Lmin and a bargraph of the level distribution In
94. 1 3 Logic input 0 to 5 volts active high 100 load 4 Wind speed input 05 to 10 Vdc peak to peak 10 load 5 Wind direction A D input 0 to 2 5 Vdc 100 load 6 Wind direction power 5 Vdc through 250 9 29 09 Introduction 1 11 Both outputs have a 600 ohm series resistance 1 12 7 Calibration control output 0 to 5 volts active high 10 8 Heater control output open drain 40 Vdc 100 mA Max 9 External power input output 8 to 15 Vdc The serial connector is used for computer printer and modem communications oog Figure 1 4 The serial connector is an 8 pin mini DIN connector AppleTalk compatible pinout 1 Flow control output RS 232C levels 2 Flow control input RS 232C levels 3 Transmit data negative output RS 232C levels 4 Ground 5 Receive data negative input RS 422 6 Transmit data positive output RS 422 7 Control input RS 232C levels 8 Receive data positive input RS 422 The AC DC output connector is used to output the signal from the System 824 microphone to external devices such as DAT recorders real time analyzers other sound vibration measurement equipment voltmeters chart recorders etc 824 Reference Manual 9 29 09 NOTE See the section AC DC Output on page 6 5 for more details concerning the AC DC outputs AC Output Tip v ES DC Out
95. 10 20 30 DOWN SETTING S86 SSA LOG INTV PERIOD S86 RTA HORIZONTAL GRAPH SCALING 1 2 3 4 6 8 11 16 23 32 45 64 90 128 181 256 362 512 724 1024 S87 SSA LOG INTV TIME SYNC S88 LOG INTV SAVE Ln S S90 SSA LOG INTV AUTO STOP S91 LOG ENABLE TIME HIST 592 LOG TIME HISTORY RESOLUTION 893 LOG Other TIME HISTORY Level 594 LOG TIME HISTORY PERIOD S95 LOG TIME HISTORY PERIOD UNITS S96 LOG HIST BASE 897 LOG HIST BASE MODE S98 LOG HISTOGRAM TABLE RESOLU TION 599 LOG ENABLE DAILY LDN HISTORY 5100 LOG SAVE 6 DAILY Ln VALUES 5101 ALL DATA REPORT 5102 SSA LOG R S AND CAL LOG 5103 ALL SETUP REPORT 9 29 09 A 43 Histogram Reports The RMS Peak UWPk histogram reports have been implemented with this revision The unformatted reports have also been developed and the format is the level of the first bin followed by the number of samples in each bin in hex 0 9 amp There 1024 RMS bins 128 Peak and UWPk bins this corresponds to 1 8th dB resolution for RMS dB resolution for the peak tables S104 LOG SPL HISTOGRAM TABLE x S105 LOG SPL HISTOGRAM TABLE LOW n VALUE S106 LOG SPL HISTOGRAM TABLE HI n VALUE S107 LOG SPL HISTOGRAM TABLE RESO x LUTION S108 LOG PEAK II HISTOGRAM TABLE x S109 LOG PEAK II HISTOGRAM TABLE n LOW VALUE 5110 LOG PEAK II HISTOGRAM TABLE HI n VALUE S111 LOG PEAK II HISTOGR
96. 15 431 28 87 9 30 8 88 2 20 18 s f 20 98 fo 20 8 osf 1 2 78 55 NF is electrical noise floor 9 29 09 C 19 1 1 and 1 3 Octave Filters The 1 1 and 1 3 octave filters SSA and RTA Options comply with all requirements of IEC 61260 1995 including amendment 1 2001 for Class 1 These digital filters are sampled at a rate of 51 200 samples per second with base 2 center frequencies and having real time performance for all filters The 0 dB gain setting is the reference range and the reference input signal is 1 Volt rms at 1 kHz Frequency Range 1 1 Octave Filters 16 Hz to 16 kHz 1 3 Octave Filters 12 5 Hz to 20 kHz Filter Shapes Filters are characterized by the shape of their filter skirts and the shape of the passbands which must fit within those specified by the standards The following figures present these for the 1 3 octave band centered at 1 kHz Overlaid with these curves are the limit curves associated with IEC 61260 1995 Class 1 1000 Hz Passband IEC Class 1 Limits 2 o 5 z a E Relative Frequency Figure 13 2 Passband of 1kHz 1 3 Octave Filter C 20 824 Reference Manual 9 29 09 9 29 09 amplitude dB 1000 Hz Filter Skirts IEC Class 1 Limits y Ape UP AT n w ww hi Nil Figure 13 3 Filter Skirts of IKHz 1 3 Octave Filter NOTE Results in dB referenced to 101 kPa C 22 Ambient Pressure Response of Free
97. 17 Key etta dete EE RE A E Nt 3 18 3 20 Calibration ene t ER e tS Uo Ip Ud Aot ces doro 3 22 Glock Timer oma t tert 3 23 Chapter 4 Chapter 5 824 Reference Manual mr tret E Y EH HE ed aee Pee dee 3 27 Deleting Stored oi niat e s 3 29 Delete Last Function 3 29 824 Memory Str ctute tese teet eee e tee vt eere i a 3 29 Deleting the Last Stored Record sse 3 30 Deleting Individual 5 3 31 Power Monitor fet iieri Dee Op OP Rent eS Ue tec em EE 3 33 Communication 2 8 epo oo uem ae 3 34 D Print Key secs metere vt et Dee ete i ted 3 37 Quick Start 4 1 Turning On and Calibrating the System 824 sss 4 1 High Range Calibration eR 4 4 Taking Measurements and Storing Data sse 4 5 SLM amp RTA Measurements oett enne eere nde pene eoe en 4 5 Viewing RTA Displays during a 4 8 Recalling Stored 2 nennen 4 11 Selecting and Modifying Instrument Definitions IDs sss 4 12 The Set p Menu ii aee res RETRO ERE EE 4 13 The Active ID s tea e P CPP RE P DUREE 4 13 Men Scrolling ice E eie A Ed Os 4 15 Permanent r
98. 18836 49 0 7 0 7 0 7 0 0 0 0 0 60 19952 62 0 5 0 5 1 0 0 5 0 5 0 75 Add numbers in this column to levels read on the 824 to correct the level at a specific frequency 9 29 09 F 3 Periodic Testing of A Weighted Sound Levels The following table presents adjustment data to be used to determine A weighted sound levels equivalent to the response to plane sinusoidal sound waves incident from the reference direction produced by a calibrated multi frequency sound calibrator and an electostatic actuator 0 02 f 0 0 Expanded Free Field Cor Free Field Correc Free Field Cor Free Field Cor taintly of Correc Frequency rections from tions with Wnd rections from rections with tions 99596 H B amp K4226 Screen from B amp K UA0033 Wnd Screen confidence z Calibrator B amp K4226 Electrostatic from B amp K4226 dB dB Calibrator Actuator Calibrator dB dB dB 31 62 0 1 0 1 0 0 0 0 0 25 63 10 0 1 0 1 0 0 0 0 0 25 125 89 0 1 0 1 0 0 0 0 0 25 251 19 0 1 0 1 0 0 0 0 0 25 501 19 0 0 0 0 0 1 0 1 0 25 1000 00 0 0 0 0 0 0 0 0 0 25 1995 26 0 2 0 1 0 1 0 1 0 30 3981 07 1 3 1 3 1 3 1 3 0 35 7943 28 3 1 3 1 3 6 3 7 0 40 12589 25 6 0 6 0 6 4 6 4 0 50 15848 93 8 2 7 9 7 8 7 5 0 60 numbers in this column to levels read on the 824 to correct the level at a specific frequency F 4 824 Reference Manual 9 29 09 A Weig
99. 2 25 seconds Logging SLM Time History Interval History For the AUD instrument AC 1 is on the tip and the DC output is not used For the RTA instrument the AC signal will be identical on the tip and ring The Logging SLM LOG instrument is ideal for applications requiring automatic measurement and storage of multiple parameters over an extended period as required for environmental noise monitoring The Logging SLM provides automatic logging of sound level parameters including Interval data L statistics noise event detection and event time history records Additionally this mode provides a dynamic range of 115 dB Like other instrument modes the Logging SLM mode is selected via the Setup menu This section covers some of the data acquisition features of the LOG instrument The System 824 Time History logs Leq readings and up to 37 additional parameters The Time History graphical display allows you to scroll through the time history and Run Stop events The following Interval History parameters can be logged at user selectable time intervals between 1 second and 99 hours hh mm ss Lmax Lmine SEL and Leq 4 3 or Time Weighted Aver age q 4 5 or 6 levels for a selected detector Slow Fast or Impulse and a selected frequency weighting A C or Flat 9 29 09 System 824 Virtual Instruments 6 7 Exceedances Ly Percentiles Broadband 6 8 Lyeak level corresponding to the frequency weighting
100. 24 by Leroy Harbaugh Note normal range with wind screen Reference B amp K Model 4133 Serial Number 1424039 Tested 05 20 99 11 20 15 dB 1K Hz Type 1 limits 9 29 09 C 29 Graph 3 The 824 in high range with the 2540 microphone 824 0170 Model 2540 Serial 4187 Normalized to l1000 00Hz 0 Tested 05 21 99 11 12 06 by Leroy Harbaugh Note high range Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 05 20 99 11 20 15 3 0 dB Type 1 limits Graph 4 The 824 in high range with the 2540 microphone and windscreen 824 0170 Model 2540 Serial 4187 Normalized to 1000 00Hz 0 Tested 05 21 99 11 24 31 by Leroy Harbaugh Note high range with wind screen Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 05 20 99 11 20 15 3 0 dB 4 ES bn 1K Hz Type 1 limits C 30 824 Reference Manual 9 29 09 9 29 09 Graph 5 The 824 in normal range with the 377B41 microphone 824 0170 Model 2541 Serial 5636 Normalized to 1000 00Hz 0 Tested 05 20 99 16 23 07 by Leroy Harbaugh Note normal range Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 05 20 99 11 20 15 3 0 dB
101. 3 28 laststored Rete leitete trt t HR 3 30 stored dataset reete tte rer iR 3 29 Demonstration Mode Model 831 Technical Reference Manual Index iv v Unen bled IDS 5 ere er Eve ee e Ee 2 6 Department of Defense level ee rea eee ORE ERE QUE EHE es D 8 D teetot arse atte mto E eerte ro eise tege utere Ais bee opea bt ep tt D 8 Diagram 1 15 Display TriciCatorsz ua Ee te th ERR e ERE RH Hte 5 2 luu EE 3 11 Status COS Lecce pee n E ues eee dE 5 2 Display Device Integrating Measurement tee oe e ERR EIE HE RD Ue on penta eae ee ete 9 12 Leyels Ranges zeit eee tenete e nt p tue F 6 Displays SS Avi E teach seeker eve een ea e ete anda ed de 5 11 SS A display SpDectta cas eei ten ea e REOR EO tunes ea eo Mte to e PEOR T te DE alates 5 11 SSA Int ry ls perdete rie ORDRE 5 13 SSA tabulartspectra o nea tee ove regir ERR 5 12 SSA Time History eer e Ee e EO RUE e e UR Ee ESSERE 5 16 Time History Displays ite oe UG EP OUR OH RATEN ean he 5 13 Displays Logging SLM Current Overall b SLM Displays esses nnne 5 28 Current Overall c SEM Displays eese et e ei eet Teide 5 29 Current Overall e SLM Displays reneis te a E E E EEN s 5 30 Expos re b Display eee eee eee HR Ee RE e 5 33 Expos re c Display ERE c n ev e
102. 6 A 100 x 1 sec Leq history EF graph LE lt q Current SPL All combinations of detector and weighting are measured simultaneously The detector and weighting selected in the Settings menu are for measurements such as Ln and Interval broadband levels 5 6 The following is a brief description of each of these components Display label The Display label identifies the display The example above shows the SLM view for the SLM RTA Instrument ID Selected detector The selection determines which detector s data e g Fast Slow Impl 15 to be displayed Current SPL reading Displays the current SPL reading as does the level of the moving bar on the far right of the SPL history graph The frequency weighting for SPL can be selected A C or FLAT The detector can be selected from Slow Fast and Impl Selectable reading This is used to view a second level which can be Leq SEL Min Max or Peak Weighting This selection determines which weighting 1s being displayed for the SPL and selectable reading When the selectable reading is showing Peak the weighting for the Peak can be set to A C or Flat independent of the current SPL frequency weighting Elapsed time Displays the current run time for the measurement It resets to zero when the RESET key is pressed pauses when the fl PAUSE key is pressed and continues when the ll PAUSE key is pressed again The timer is displayed
103. 824 setup can be specified Save Setup to a File Save in a 824 Utility 23 Temp default ssa Test Setssa File name est Se Save as type Ssa ssa Simple Sound Analyzer Setup z Cancel Open as read only The System setup can be modified and stored back into the 824 but cannot be saved to a disk file Opening Setup Disk Files To open a setup disk file select the Open Setup File menu item from the File menu or click on the Open File button on the tool bar 10 12 824 Reference Manual 9 29 09 A standard windows Open File box will appear Select the file folder that contains the file and select the setup file you want H Select Setup File to Open 215 amp y e ez a _ default ssa Oe Sondra al a The setup appears in the Select Setup list box You can then select highlight the desired setup in the list The high lighted setup can then be sent to the 824 by selecting the Save Setup to 824 menu item from the File menu Enter Company Name Enter Address Line 1 Enter Address Line 2 Other menu items available in the Setup Menu include renaming locking unlocking deleting or making the selected setup the active setup 9 29 09 Using the 824 Utility Software 10 13 Creating a New Setup You create new setups by selecting the New Setup menu item from the File menu or by selecting the New Setup but ton on the tool
104. 9 29 09 Display label pDailu d Windy m Date Wed i np znn2 18 ar 2 t 2 Windy Directional Duration p 11 31 H lt q Distribution Hu E Windy Mind BH t B gt 454 B Hourly Leq Display 9 29 09 The following explains each of the display s components Display label This shows the current display for example Daily d Wind Record Number Each Daily record is shown in the order that it occurred The record number indicates the order of the displayed Daily record in relation to the other records A new daily record is created each new day A day is defined as 12 00 midnight to 12 00 midnight Percent Windy Condition The Percent Windy Condition is the percent of the time the windspeed was above the Windy Threshold Level Windy Directional Distribution The Windy Directional Distribution is shown on a compass rose with indications of the percent of the time that windspeeds above the Windy Threshold Level were in the directions covered by each of the eight directional coordinates For example in this instance winds having levels above the Windy Threshold Level of 5 04 shown on the Daily c View were from the North West 68 of the time The Hourly display consists of 7 major components System 824 Views 5 63 Display label Date Record Number Hourly Leq reading Exceedance Background Leq e Partial hour indic
105. C weighted value from the System 824 s peak detector along with the date and time that the peak event occurred Current Overall A Weighted Peak reading Shows the A weighted value from the System 824 s peak detector along with the date and time that the peak event occurred The Current Overall e SLM display consists of four major components Display label TWA indicator and level 824 Reference Manual 9 29 09 Sound exposure level Elapsed time The SLM Current e or TWA display is shown below TWA indicator and level Display label 914 5L 1 Current e X TWA Sound exposure level 34E SEL Elapsed time gt HB dMz 1 Leg 53 5 dBA Exposure Views The and W arrow keys can be used to cycle between the Current SLM Overall SLM Exposure Ln Centiles and Stats views 9 29 09 The following explains each of the display s components Display label This shows the current display for example SLM Current e The display represents both Current and Overall e display TWA indicator and level The indicator is based on the exchange rate Leq for 3dB exchange rate and threshold 0 TWA for all others and the Time Weighted Average level Sound exposure level The Sound Exposure Level SEL is measured in dB This is the TWA normalized to one second Elapsed time This shows the elapsed run time accumulated since the last current overall res
106. Current SLM Overall SLM Exposure Ln Centiles and Stats views The Stats a display consists of three major components Display label Trigger level 1 and event counter Trigger level 2 and event counter The Stats a display is shown below and event counter SPL and event counter Display label 5 SLM 5t atz a SFL exceeded Trigger level 1 1 1 5dBEH B Limes Trigger level 2 176d exceeded EB times Stats b Display 5 38 The following explains each of the display s components Display label This shows the current display for example SLM Stats a Trigger level 1 and event counter This presents a summary of the number of times during the overall measurement that the SPL exceeded the pre programmed trigger level 1 In this example trigger level 1 is set to 115 dBA and the SPL exceeded this threshold 0 times These may be considered as individual events Trigger level 2 and event counter Summary of the number of times during the overall measurement that the SPL exceeded the pre programmed trigger level 2 In this example trigger level 1 is set to 120dBA and the SPL exceeded this threshold 0 times These may be considered as individual events The Stats b display consists of three major components 824 Reference Manual 9 29 09 Display label e Peak I trigger Peak II trigger The Stats b display is shown below Display label ISL TI S
107. D channels 824 Reference Manual 9 29 09 Logic Output Time Setting SSA LOG ISM 9 29 09 P A The Logic Output turns on when a Peak exceedance event occurs or when an event occurs on one of the A D channels R P A The Logic Output turns on when either an RMS or Peak exceedance event occurs or when an event occurs on one of the A D channels I A The Logic Output turns on when each inter val begins or when an event occurs on one of the A D channels R I A The Logic Output turns on when RMS exceedance event occurs when each interval begins or when an event occurs on one of the A D channels P I A The Logic Output turns on when a Peak exceedance event occurs when each interval begins or when an event occurs on one of the A D channels R P I A The Logic Output turns on when either an RMS or Peak exceedance event occurs when each interval begins or when an event occurs on one of the A D channels R S The Logic Output turns on when the instru ment is in run mode and turns off when the instru ment is in stop mode The Logic Output turns on when a valid exceedance is detected and after it s minimum duration has been met The Logic Output Time sets the number of seconds that the logic output will remain turned ON following a triggering event Accordingly this setting can take on any integral value within the following range 0 sec to 255 sec Using ID Setting Files 7 15 NOT
108. DNL Day Night Average Sound Level display shows the equivalent sound level for a 24 hour period with a 10dB weighting applied to all sounds occurring between the times 22 00 and 07 00 CNEL Reading The CNEL Community Noise Equivalent Level display shows the equivalent sound level for a 24 hour period with a 5dB weighting applied to all sounds occurring between the times 19 00 and 22 00 and a 10dB weighting applied to all sounds occurring between the times 22 00 and 07 00 9 29 09 System 824 Views 5 59 Daily b Display Maximum and Minimum levels This shows the maximum and minimum levels during this day s measurements Peak level This shows the peak level during the day with different weighting applied The Daily b display consists of 4 major components Display label Record Number Date LnPercentiles The Daily b display is shown below Date Display label Da i 1 5 ir 24 lt g Record Number Ln Percentiles Li B 8 13 41 6 Las 39 5 1500 34 3 Lago 24 8 Tue 157411999 5 60 The following explains each of the display s components Display label This shows the current display for example Record Number Each Daily record is shown in the order that it occurred The record number indicates the order of the displayed Daily record in relation to the other records A new daily record is
109. Exceedance Level LOG S71 RTA RTAf TRIGGER TIME SS SSSS SECONDS S72 SSA ISM Peak I Exceedance Level LOG S72 RTA RTAf TRIGGER SAMPLES NNNN S73 SSA ISM EXCD HYSTERESIS LOG S73 RTA RTAf TRIGGER LOGIC INPUT LOW HIGH TRUE LEVEL S74 LOG ENABLE EXCD HISTORY S74 RTA RTAF RUN MODE LOGIC INPUT LOW HIGH 9 29 09 A 41 S75 LOG EXCD EXCHANGE RATE S75 RTA RTAf LOGIC OUTPUTS CONTROL BIT MAPPED WORD 3 SETTING OUTPUTS BY 5 STATES 576 LOG EXCD MINIMUM DURATION S76 RTA RTAf END MODE NEVER L lt L L gt INPUT TIME COUNT S77 LOG EXCD TIME HIST ENABLE S77 RTA RTAf END LEVEL NNN N dB S78 LOG EXCD TIME HIST PERIOD S78 RTA RTAf END TIME SS SSSS SECONDS S79 RTA RTAf END SAMPLES NNNNN S80 LOG EXCD Passby Trigger Mode S80 RTA RTAf END LOGIC INPUT TRUE LOW HIGH LEVEL S81 LOG EXCD Occurrence Time Start Max S81 RTA RTAf END THEN REPEAT MODE STOP REPEAT AVER AGE S82 LOG TIMED EXCD PERIOD MM SS S82 RTA RTAf REPEAT COUNT NNN O TO 255 TIMES 583 SSA LOG ENABLE INTV HISTORY 583 RTAf AVERAGE COUNT N 0 TO 9 TIMES S84 SSA LOG INTV EXCHANGE RATE S84 RTA RTAf ANNUNCIATOR CCCCCCCC IF RIGHT DIGIT IS NUMERIC IT WILL AUTO INCRE MENT S85 SSA LOG INTV THRESHOLD 42 824 Reference Manual 9 29 09 S85 RTA RTAf RT 60 CALCULATION dB 5
110. F9 5 Locates calibration history record 9 A 56 824 Reference Manual 9 29 09 Generally you use the Find command to get to the first record F1 2 and the Advance command A to move up through the records History Data Variables Exceedance History Variables Brackets in the syntax indicate optional characters and operands Syntax Response E xceedance var no Excd var Example E9 __2 Overload count from current record Commands Instrument Description Commnet Type El LOG RTA Date and Time of Occurrence ddmmmyy hh mm ss E2 LOG RTA Duration hh mm ss mm ss ss E3 LOG TWA nnn n dB Leq Filter E4 LOG SEL nnn n dB EA f RTA Max filter 5 LOG Lmax nnn n dB ES f RTA Min Filter E6 LOG Lpeak nnn n dB E6 RTA Overload 9 29 09 Commands Instrument Description Commnet Type E7 LOG UnWeighted Peak nnn n dB E7 RTA Pretrigger Samples 8 LOG Peak Exceedance Count nnn E8 RTA Trigger Samples E9 LOG Overload Counts nnn E9 RTA Total Samples 0 LOG Illegal Indication BEEP ILLEGAL E10 RTA Pre Post Trigger indication Ell n RTA Sets ByTime Sample If n 0 no change just report current sample E12 f RTA By Time Sample Filter Level E13 n RTA ByTime Sample Time E14 n RTA By Time Sample Duration 15 By Time Overload E16 RTA RT60 calculation
111. FFT Optional 12 19 05087g 1216186 4 182748 x 10 8 now use this R as the reference to get the readings in linear units from dB like this L R 10 D 20 L 4 182748g x 10 8 10 121 7dB 20 L 4 182748g x 10 8 10 6 085 L 4 182748g x 107 8 1216186 L 0 05087g Another example this time down 20 dB L 4 182748g x 10 8 10 101 7dB 20 5 087 x 10 3 0050876 How can manually enter a calibration offset so that the decibel levels dB from the FFT option of the 824 are relative to 1 micro meter per second squared The calibration offset is calculated with this formula 45 accurate LCAL 20 log 4 467 nanovolts Vref Where LCAL is the calibration offset being calculated Vref is the desired reference voltage the voltage that would read 0 dB and 4 467 nanovolts is a constant set by the 824 s electronic design 4 467x10 9 Example It is desirous to display 140dB for 1 g due to the relationship that 1 g 15 10 meters per second squared m s2 and 1 micrometer per second squared mm s2 is a common reference level Given that an accelerometer with a sensitivity of 0 1V g has a sensitivity of 0 01 volts per meter per second squared 10 mV m s2 The voltage at 1 mm s2 would be 0 01 microvolt calculated ratio metrically since 12 20 824 Reference Manual 9 29 09 9 29 09 1m s2 outputs 0 01V then 1m m s2 will have an output of 0 01mV LCAL 20 log 4 467 nV 0 01mV 20 log 0
112. Field Microphones Variation over Static Pressure Pressure 65 kPa 75 kPa 85 kPa 93 kPa 101 kPa 110kPa 2520 38 dB 20 dB 14 dB 069 dB 0 000 047 dB 2540 34 dB 24 dB 15 dB 08 dB 0 000 075 dB 377B41 43 dB 31 dB 19 dB 099 dB 0 000 10 dB Position of Instrument and Operator When making a measurement it is recommended that the observer be positioned as far behind and to the right of the instrument as possible to minimize interference of the sound field at the microphone resulting from body reflections When using the 824 the meter is held in one hand with the arm extended away from the body Better results can be obtained by using a tripod Effect of Windscreen The Corrections which should be subtracted from the measured data when using the Larson Davis Model WS001 31 2 inch diameter windscreen with a 2 inch Larson Davis microphone are as indicated in the following graphs 824 Reference Manual 9 29 09 Windscreen Response with Respect to No Windscreen 0 Degree Incidence Frequency Hz 9 29 09 C 23 Frequency Response NOTE Tested with the preamplifier and microphone attached directly to the 824 C 24 90 Degree Incidence Frequency Hz Random Incidence Microphone Correction When random incidence correction is turned on in the 824 a digital filter is added which gives the necessary correction to provide random incidence response when measuring with a
113. Flat A weight C weight and 10 Hz high pass filters ahead of the Analog to Digital Convertor most of the measurements use digital weighting filters created by the Digital Signal Processor The Digital Signal Processor implements the following in order to provide measured data for a wide range of weightings filters and detectors A C and Flat broadband filters Real time FFT and 1 1 and 1 3 octave band filters Slow Fast and Leq true RMS detectors Impulse and Peak detectors Accessories and Optional NOTE Two Terminal assemblies are provided though only one is used The second one is a spare To avoid losing them keep them in the accessory kit in the carrying case provided 1 16 Equipment The System 824 8245 824L and 824A can be purchased with or without a microphone they all include the Model PRM902 microphone preamplifier The System 824 824L and 824A are delivered with the following standard accessories 824 ACC Pack Battery pack NiMH 3 6 V 1 2 AH BAT010 Reference Manual 1824 01 Serial cable DB9S to DINO8 CBL006 AC DC output cable 1 8 mini phone plug to dual phono or BNC CBL042 Universal AC power adapter 90 to 264 Vac 50 to 60 Hz 12 volt output PSA027 Alkaline battery terminal assembly 814 06 Connects individual alkaline batteries when NiMH battery pack is not used 824 Reference Manual 9 29 09 9 29 09 Hard case 15 x19 x7 CCS001 with foam insert 0
114. Hist Report Yes Leq for each time history period Print Range Intv Report Short You can customize the interval report by choosing the long or short report Lowest Record 00000 Selects the lowest interval record to be printed Highest Record 65535 Selects the highest interval record to be printed Hist Report Yes You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time history record to be printed Highest Record 799999 Selects the highest time history record to be printed 8 16 824 Reference Manual 9 29 09 Short Report Template LOG instrument Histograms SPL Histogram Yes You can customize the SPL Histogram report by choosing the long or short report Lowest Level 045 Selects the lowest SPL histogram level to be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 5 0 Selects the SPL histogram resolution Pk 1 Histogram Yes You can customize the Peak Histogram report by choosing the long or short report Lowest Level 110 Selects the lowest 1 histogram level to be printed Highest Level 160 Resolution 5 0 Selects the highest Peak1 histogram level to be printed Selects the Peakl histogram resolution Pk 2 Histogram Yes You can customize the Peak2 Histogram report by choosing the long or short report Lowest Level
115. ID Setting Files 7 59 toggle between a views tabular mode or graphical spectrum mode This section will present the following e Check Menu Example SLM Check Menu Options Other SSA Check Menus Other Logging LOG Check Menus Check Menu Example Use the W keys to move from one setting to the next Then use the key to change the selected setting The key is used to return to previous menus 7 60 The Check menu is accessed by simply pressing the Check key from within an Instrument ID s view The following is an example of using the Check menu from a SLM view to change the Detector setting from the selected instrument s SLM display Step 1 From the Instrument s SLM LOG or SSA view display press the key to access the Check menu menu similar to the following appears SIM Settin Controls 824 Reference Manual 9 29 09 Step 2 Pressing the right D arrow key Step 3 takes you to a different place than pressing the check Q key See example below SLM n eH ark Settings gt Graph Controls gt Y A box with an arrow next to a menu item indicates that you use the right Yarrow key to access another display or menu The check Y key takes to a different place An empty box indicates that a check Q takes you to the same place as the right arrow key Step 4 Step 5 9 29 09 Using ID Setting Files Use the
116. Interval and Interval Ln is enabled and the Interval Period is 00 00 00 then the Interval Period is set to 00 00 01 one second and the warning Setting Conflict is displayed Marker Text LOG SSA 9 29 09 Up to 40 different parameters can be stored LOG and SSA with each time history period including Wind Tach data and spectral data SSA only These are all user selectable in the Advanced Time History displays The Advanced Time History displays are shown below TH amp etup b H Adv amp etup c H Mind Tach Temperature External Molt Battery Wolt Hext Done SSA amp LOG Ady TH Setup b T Live F I B o o LAFTMS Hext Done LOG only with Takt OFF LOG only with Takt ON Once the Advanced Time History displays have been selected do the following to navigate through and setup each display Use the up amp and down and left and right arrow keys to move the cursor between each selec tion or check box The Check Y key toggles the selection on or off The Reset key will uncheck all the items on the current display To move to the next screen a b or c highlight Next and press the Check Y key When all of your selections have been made highlight Done and press the Check key One of the features of the 824 is the ability to mark or annotate the SLM Time History as the instrument is running This allows the u
117. Intv Ln 1 Percent nn SSA LOG Intv Ln 1 Level dB nnn n I12 SSA LOG Intv Ln 2 Percent nn I13 SSA LOG Intv Ln 2 Level dB nnn n I14 SSA LOG Intv Ln 3 Percent nn I15 SSA LOG Intv Ln 3 Level dB nnn n I16 SSA LOG Intv Ln 4 Percent nn I17 SSA LOG Intv Ln 4 Level dB nnn n I18 SSA LOG Intv Ln 5 Percent nn I19 SSA LOG Intv Ln 5 Level dB nnn n 120 SSA LOG Intv Ln 6 Percent nn 121 SSA LOG Intv Ln 6 Level dB nnn n I22 n SSA LOG Differences 0 to 2 LAFTMS LAeq LCeq LAeq LAleq LAeq T Commands for Tonal Mode Commands Instrument Description Comments Type I5 TAL Ftone nnnnn Hz I6 TAL Dfc nnnnn Hz I7 TAL Ltone nnn n dB 9 29 09 A 63 Commands Instrument Description Comments Type I8 TAL Lgroup nnn n dB 19 TAL Ltone Lgroup nnn n dB Daily History Variables D1 D102 Brackets in the syntax optional characters and operands indicate Syntax Response D aily var no hour daily var Example D5 5 hourly noise level for hour 5 to 5 59 59 a m D1 LOG Date ddd ddmmmyyyy D2 LOG Daily Leq nnn n dB D3 LOG Daily LDN nnn n dB D4 LOG Daily CNEL nnn n dB D5 hn LOG HNL for hour 0 23 nnn n dB D6 hn LOG HNL partial hour indicator D7 LOG Daily Lmin nnn n dB D8 LOG Daily Lmax nnn n dB D9 LOG Daily Lpeak nnn n dB D 10 LOG Daily Luwpk nnn n dB Dil LOG Daily Run Time hh mm ss mm ss ss D 19 L
118. Level i dto ntc n RU SUED WR d ed 11 11 Trigger 11 11 Trigger Settings Menu eet eed eite eae deus 11 11 Trigger SOUrce csetera erede e e i He e P ies 11 9 11 11 Trigger Views i Rte re ee ee tive er v v ee 11 23 TTS BERING ite teo We SLE et oot e Pa PREIS RR HUN GR RUNE EATUR 11 9 Ens iere eerte 7 69 UE ROO oe rt G 8 Run a meet ene ER C EU imn teo 3 26 Run Log Check Menu eo Gh RE UR ees 7 15 Display tica idea it etes tat tn ede atus Gba hee S eh eire 5 40 R n ET ER 3 26 R n Stop Key aceites bee REESE OG NE Tod BRUM DR nate 3 8 S SEE Calculations 3 2 eot ate Ue a eae B 5 Selecting pee 4 12 Measurement Setup E 2 6 MIC WS XP EE 2 11 Serial Address s P a 3 35 Serial connector tu pis Ree Ee bb ieee 1 12 Settings Examples S BOOTE S 7 2 Men ede etate irte eti ee ido eat ie dede perd te P 4 17 iv xviii Index Model 831 Technical Reference Manual Setup 10 10 3 14 Rota ra te RO ER e tein 4 13
119. Level or HTL for this spectrum Graph Adjusts the graph scale and offset See 824 Ref erence Manual Graph Level Allows numerical entry of graph level in dB Graph Scale Allows numerical entry of graph scale ByTime Graph Check Menu Pressing the Y check key once when viewing ByTime spectrum display puts you in the check menu The check menu is shown below 9 29 09 RTA optional 11 31 The check menu gives you the following options The Locate menu helps you find the record you would like to view ByTime Spectrum View the Bytime spectrum Autostore View the Autostore Leq Max and Min spectrum Locate Locate an Autostore ByTime record Next The next Autostore record Prev The previous Autostore record First The first ByTime record Last The last ByTime record Find Finds the specified ByTime record Graph V Adjusts the vertical graph scale and offset Graph Level Allows numerical entry of graph level in dB Graph Scale Allows numerical entry of graph scale 11 32 824 Reference Manual 9 29 09 The horizontal graph adjustment Graph H provides a useful feature that allows you to view a large amount of time data the ByTime Graph view A scale factor of 1 to 1024 can be selected A scale factor of greater then 1 will cause multiple pieces of time data to be graphed to 1 bar The measured data can be viewed by pressing the 4 left or right arrow key
120. Miscellaneous Commands unsupported Key Simulation Commands K A 8 824 Reference Manual 9 29 09 Remote Control Commands Detailed Mode Commands Format for the Mode Commands is Command Description MI Power On clear error message list and reset display functions to a windows M2 Power Off cease sending further commands or the 824 will power back on M3 Run begin accumulating data M4 Stop stop accumulating data M4 1 Pause Continue or View End view if stopped See R152 through R154 5 View view the current Sound Pressure Level without accumulating data M6 or Set standard mark M6 0 M6 1 Set mark 1 Aircraft M6 2 Set mark 2 Automobile M6 3 Set mark 3 Truck M6 4 Set mark 4 Train M6 5 Set mark 5 Animal M7 or Reset current data instantly resets the current data set M7 0 M7 1 Overall Reset Resets the Current and Overall SLM function and histories synonym of S1 1 Reset All command M7 2 Purge All Resets ALL data and erases ALL data files To purge error checking must be on the check character for M7 2 is b therefore the complete purge com mand is M7 2b case is significant M8 Reset Histories Only clears all histories and places a RESET record in the run log 9 29 09 A 9 M 9 1 Enable High Resolution Levels nnn nn for all sound level data to I O channel M 10 Lock 824 le
121. Percent Selectable default 66 67 Ln 6 Percent Selectable default 90 Triggering SPL Excd Lvl 1 0 255 dB default 115dB SPL Lvl 2 0 255 dB default 120dB PK 1 Excd Lvl 0 255 dB default 140dB 2 Excd Lvl 0 255 dB default 140dB Hysteresis 0 9 dB default 2dB 9 29 09 Using ID Setting Files 7 53 7 54 Time History Hist Enable Yes default No Hist Period 0 255 default 60 Period Units 1 32s 1s default 10s 60s Other Level None default Pk II Pk I Lmax Advc Resolution 0 1dB default 1 0dB Adv TH Activates a set of 3 displays used to configure what type of time history data will be stored See Advanced Time History LOG SSA on page 7 35 Marker Text Marker 1 Aircraft Marker 2 Automobile Marker 3 Truck Marker 4 Train Marker 5 Animal 824 Reference Manual 9 29 09 Intervals History Intv Enable Yes default No Intv Period 0 24 0 60 0 60 hh mm ss Intv Time Sync Yes default No Intv Save Ln s Yes default No Intv Auto Stop Yes No default Intv Threshold 0 255 dB Intv Exchange 3dB default 4dB 5dB 6dB Triggering SPL Excd Lvl 1 SPL Excd Lvl 2 PK 1 Excd Lvl PK 2 Excd Lvl Hysteresis Excd Enable Yes No default Min Duration 0 999 seconds Excd Time Hist Yes No
122. Resolution 5 0 Selects the Peak1 histogram resolution Pk 2 Histogram No You can customize the Peak2 Histogram report by choosing the long or short report Lowest Level 070 Selects the lowest Peak2 histogram level to be printed Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 5 0 Selects the Peak2 histogram resolution 8 22 824 Reference Manual 9 29 09 Printing a Custom Report The ISM instrument does not allow printing customized reports For your report to print properly your printer must be connected as described in Connecting the 824 to a Serial Printer on page 8 1 configured as described in Printing Reports on page 6 2 9 29 09 In addition to being able to print your standard reports for data taken with the SSA LOG or RTA instruments you can also further customize your report definitions at print time with the Print menu s Customize option The following provides an example of printing a customized report Step 1 Step 2 Step 3 Step 4 Printing a Report Press key to bring up the Print menu Use the 43 and W arrow keys to highlight the Customize item then select it using ther arrow key or the Y Check key The following screen appears Cuztomize Unformatted Data REPPE TS Loe Rep E Use the and 5 arrow keys to scroll through the available report settings Use the
123. Save setup to a file In the Save setup to a file window type in default under File name and select Save The new setup is now defined for a particular instrument ID and can be modified from the Setup List box After creating a new setup you can store it to a disk file or send it to the 824 Renaming an Existing Setup 9 29 09 To rename an existing user defined setup right click on the setup 1n the left hand side of the screen and select Rename Setup from the popup menu Rename Setup Using the 824 Utility Software 10 15 NOTE The permanent setup ID in the 824 cannot be renamed Deleting an Existing Setup NOTE This section applies only to setups that exist on the 824 If a new setup or a setup that is stored to disk is deleted this message will not appear WARNING 10 16 A dialog box will be displayed to allow you to change the name of the selected setup Cancel Setup Name JEM eiiis Enter the new name for the setup and press the OK button After renaming a setup you can store it to a disk file or send it to the 824 To delete an existing setup right click on the user defined setup in the left hand side of the screen and select Delete Setup from the popup menu Pressing the Delete Setup button will bring up a prompt ask ing if you are sure you want to delete the setup 824 Utility 9 Deleting the setup 8 HFT FFT will cause it to be removed f
124. Slow and Impulse Lmin Fast Slow and Impulse and Lpeak measured with A C and Flat weighting as follows Any T imen F gg pagr LM ast 24Apr i 8 AER Any Time e Any Time f D i Lmin Impl 45 Fast BF p z4RHpri9or 14 23 44 Bd EE 14 55444 2 amp dBR 1997 5545 9 29 09 The System 824 has various displays for the SSA instrument Understanding these displays lets you take full advantage of this instrument In addition to the SLM and Any Data views described earlier in this chapter there are four spectral displays System 824 Views 5 9 To store interval spectral Ln levels set Spectral Ln to Interval enable Ln Interval histories and set Intv Save Ln to Yes 5 10 available in the 55 instrument the Live instantaneous spectrum the RTA Leq or time weighted averaged since last reset spectrum RTA Max spectrum which is the spectrum time coincident with the maximum value of the SPL during the measurement interval and RTA Min which shows the minimum level obtained by each filter during the measurement interval There are also displays for the Interval History the Time History the Run Log and for Ln Centiles Like all of the System 824 displays these views are accessed via the View key as described earlier in the General Views section of this chapter The following briefly describes the main views available to the SSA instrument Menu Pu
125. Specific use of the terms defined are in the main body of the text It is the allowed time of exposure to sound of a constant A weighted sound level given a chosen Criterion Level Criterion Duration and Exchange Rate The equation for it 18 T 1 fg VO 42 54 where L is the Criterion Level T is the Criterion Duration Q is the Exchange Rate K is the Exchange Rate Factor and Lavg is the Average Sound Level Example If L 90 T 8 Q 3 and L 95 then E 8 DUNS E 1095 90 10 405 9973 5 656 5 hours and 39 minu This means that if a person is in this area for 5 hours and 39 minutes he will have accumulated a Noise Dose of 100 Standard ANSI 512 19 D 1 Average Sound Level Layg It is the logarithmic average of the sound during a Measurement Duration specific time period using the chosen Exchange Rate Factor Exposure to this sound level over the period would result in the same noise dose and the actual unsteady sound levels If the Measurement Duration is the same as the Criterion Duration then Layg7LrwA LC 1 Lg 410810 zl 10 L004 where the Measurement Duration specified time period is T T T and q is the Exchange Rate Factor Only sound levels above the Threshold Level are included in the integral Standard ANSI 12 19 Community Noise Equivalent A rating of community noise exposure to all sources of Level CNEL Lden sound that diff
126. THD information is only available on screen at the time of the measurement and is not stored with a file or printed to a report Entering the THD display will auto position the cursor to the fundamental frequency on the FFT screen 9 29 09 Results are reported in dB down difference and units of percentile The dB down difference is calculated by subtracting the harmonic level from the fundamental level The percentage is equal to one hundred times ten raised to the power of the result of the dB down difference divided by twenty THD is calculated by scanning the full spectrum to find the fundamental frequency and selecting the highest peak The actual frequency is extrapolated from the fundamental bin frequency and the highest sideband bin frequency The second harmonic is found by doubling the fundamental frequency then finding the nearest bin frequency and summing its level with it s side band levels The third harmonic is found by tripling the fundamental frequency then finding the nearest bin frequency and summing its level with it s side band levels The fourth and higher harmonics are found by the process described above for the second and third harmonics THD n is calculated by summing the energy of the fundamental bin with the five bins on each side then subtracting the energy sum of all the other levels For THD to be calculated the following criteria must be met FFT Optional 12 9 THD Check Menu 12 10
127. TWA Ovll Criterion Sets the TWA level which constitutes 100 dose for the overall measurement Criterion Time Sets how long of an exposure time for the TWA level you can have before 100 dose occurs for the overall measurement The Ln Centile view has access to the following Check menu Graph MC 824 Reference Manual 9 29 09 Menu Items Purpose Settings Modifies the Ln percentiles settings for the selected instrument Graph Changes the scaling of the instrument s Ln b Centiles graph Stats Check Menu The Stats view has access to the following Check menu Event Counting SPL Excd Lvl Pk 1 Excd Menu Items Purpose SPL Excd Lvl 1 Sets the lowest SPL trigger level SPL Excd Lvl 2 Set the higher trigger level Pk 1 Lvl Sets the trigger level for the primary peak detector i e Pk I Pk 2 Excd Lvl Sets the trigger level for the secondary peak detector i e Pk II Hysteresis Sets a hysteresis value to prevent multiple triggering counting of the same event Run Log Check Menu See Run Log Check Menu on page 7 75 for a description of the Run Log check menu for the LOG instrument 9 29 09 Using ID Setting Files 7 75 Time History Check Menu The Time History view has access to the following Check menu Hark of Locate Settings Settings EE h
128. The Excd Enable setting allows you determine whether or not exceedance data will be stored memory when exceedance trigger conditions are met This setting provides the following two options Yes Exceedance data will be stored in memory when exceedance conditions are met No Exceedance data will not be measured or stored in memory when exceedance conditions are met Min Duration LOG The Min Duration setting allows you to determine the minimum number of seconds an exceedance must last for it to be logged This setting can take on any time value in the following range 0 255 second 7 40 824 Reference Manual 9 29 09 Excd Time Hist LOG T H Period LOG Excd Trigger LOG Note Minimum duration is not considered when using Exceedance Trigger Passby Mode Excd Time LOG Using the symmetry data provided with every exceedance it is possible to calculate the time of the Max even though you choose to record the start time of the event Timed Excd Period LOG 9 29 09 Using ID Setting Files The Excd Time Hist setting enables you to indicate whether or not to have an Exceedance Time History saved as part of the exceedance This setting provides the following two options Yes The Exceedance Time History will be saved No The Exceedance Time History will not be saved Period setting allows you to set the period of time for the Leq stored in the Exceedance Time
129. The event is triggered when a level goes over a corresponding trigger level but does not become re armed until the level drops below the value of the trigger level minus the hysteresis value 824 Reference Manual 9 29 09 dB Begin Y Hysteresis 5 Trigger Time This setting can include any integer value within the following range 0 to 9dB LOG and SSA Wind Tach Settings Other transducers providing similar pulse trains and voltages representing measured parameters could also be utilized in this manner For example engine tachometers frequently output such pulse trains and throttle position indicators usually output DC voltages The setup permits the selection of units for both parameters which would be consistent with this alternative to windspeed wind direction 9 29 09 This feature is used most frequently with external weather transducers providing an analog pulse train whose frequency is proportional to windspeed and a DC voltage proportional to wind direction However other transducers could be utilized as explained in the left column In the following description it shall be assumed that windspeed and wind direction transducers are being used For the LOG instrument these data are logged with the Daily Advanced Time History Interval and Exceedance records as selected by option settings For the SSA instrument these data are logged with the Advanced Time History
130. Time History No Logging Intervals sound level Exceedance Events and spectral data Intervals sound level Major Applications Noise Reduction Sound Noise Monitoring Noise Point amp Shoot Power Workplace Law Enforcement Workplace Noise After an ID has been created it can be protected or locked or deleted if necessary This is described in detail in the section Write Protect Delete Write Enable IDs on page 3 17 The SSA ID performs simultaneous sound level measurements and real time spectrum analysis using 1 1 or 1 3 octave bandwidths The Instrument Type designation SSA represents Sound Spectrum Analyzer Sound levels during the measurement period are displayed and can be stored for later recall In addition to a live spectrum display the System 824 can display an equivalent level Leq spectrum a minimum bin by bin level Lmin spectrum and a maximum level Lmax spectrum which is the spectrum time 824 Reference Manual 9 29 09 Live SPL Detectors Detectors Detectors coincident with the maximum value of the sound pressure level during the measurement period A back erase function allows the removal of up to the last 30 seconds in one second steps of data when a disruptive noise occurs The 824 also provides an automatic measurement and logging feature which provides the sound level parameters Leq SEL Linax Lpeakand the Leq and Max or Min spectra data at regular user defined time intervals
131. Toolbar functions can also be performed from the pull down menus at the top of the 824 Utility Software screen 10 4 824 Reference Manual 9 29 09 Connect button This button is used to establish a connection to the 824 Pressing this button will bring up the connect dialog box where the connection parameters can be defined Retrieve Setups from 824 This button will retrieve all current setups in the 824 Create new setup button This button will allow the user to create a new setup that can then be saved to disk or saved in the 824 Open a setup from a computer file This button will allow the user to retrieve previously stored setup files Store setup to disk This button will allow the user to store a setup to a disk Store setup in 824 This button will store the setup in the 824 This function must be T performed before the setup can be used inside the 824 Setup window button This button will activate the setup window portion of the 824 Utility Program 9 29 09 Using the 824 Utility Software 10 5 Download window button This button will open the download section of the 824 Utility program Translate window button This button will open the translate section of the program It Sn will provide a file tree where the contents of 5 the downloaded measurement files can be viewed Export measurement button Exports the currently selected
132. Y Check key to select the settings that you want to modify then make the modifications Use the 4 arrow key to completely back out of the Customize menu screen then use the W ar row key to highlight the Print item then select it using the Y Check key Your Customized report will now print 8 23 Spectral LNs are printed in the Long Intv Report 8 24 The following table shows the available options under the Customize menu for the SSA instrument Menu Items Options Unformatted No Yes Data Report No Yes Setup Report No Yes Intv Report No Short Long Hist Report No Yes Print Range Intv Report No Short Long Lowest Record Highest Record Hist Report No Yes Lowest Record Highest Record Histograms SPL Histogram No Yes Lowest Level Highest Level Resolution Pk 1 Histogram No Yes Lowest Level Highest Level Resolution Pk 2 Histogram No Yes Lowest Level Highest Level Resolution 824 Reference Manual 9 29 09 The following table shows the available options under the Customize menu for the LOG instrument Menu Items Options Unformatted No Yes Data Report No Yes Log Report No Yes Setup Report No Yes SPL Histogram No Yes Excd Report No Short Long Intv Report No Short Long Hist Report No Yes Daily Report No Yes 9 29 09 Printing a Report 8 25 NOTE See the section S
133. accessed by pressing the right mouse button while within the Setup list box Setup Menu items will appear enabled or disabled depend ing on the setup selected For example it is not possible to delete a permanent 824 setup so the Delete Setup menu item will be disabled if a permanent 824 setup 18 selected SLM RTA Ln Time History ID System Could aint Mi Rename Setup Make Setup Current m Lock Setup zum Unlock Setup ms Delete Setup The Rename Setup button allows you to rename the selected user defined setup The Make Setup Current button will cause the selected setup to become the Active setup in Make Setup Current the 824 The Lock Setup button will write protect the selected setup in the 824 The Unlock Setup button will write enable the selected setup in the 824 Unlock Setup The Delete setup button will delete the selected user defined setup from the 824 Delete Setup 9 29 09 Using the 824 Utility Software 10 11 Saving Setups to Disk Files Once you have created or modified a setup you can store the setup to a file Select the Save Setup to a File menu item from the File menu or click on the Save to File button on the tool bar NOTE The system setup is The 824 Utility program will bring up a standard windows automatically updated each time the 824 save dialog box where the file name and location of the Utility is connected to the
134. and Printer tasks and the clear the break data and command buffers It will also address all instruments first command should be an address lt break gt Three breaks in a row will cause all 824s on the network to temporarily change lt break gt to 9600 baud to ensure that all devices on the net can be communicated with lt break gt Note The baud rate is not changed if in modem mode and connected These should be Long breaks gt 50ms to accommodate a unit set at 300 bps Use the 52283 n command to temporarily set the I O baud rate where n indicates the new rate see pg B 30 9 29 09 Commands The commands a series of ASCII characters with an alpha command and one or two numeric operands followed by a carriage return ASCII 13 The commands may be spelled out though only the first character 1s significant i e READ 123 may be abbreviated to R123 Every command has response to acknowledge that it was received correctly and to provide data requested For high reliability systems there is an error checking protocol that will ensure proper command data transferal See Error Checking Protocol Commands discussed according to the following list History Oriented Commands Commands Symbol Mode Commands M Read Commands R Settings Commands S ELD LC H T Print Commands P Error Messages amp Warnings Commands Modem Control Commands
135. are achieved by desensitizing the microphone reducing its polarization voltage from 200 volts to 20 volts See Gain Setting SSA on page 7 6 for more details The frequency resolution for each line is the bandwidth divided by the lines setting With the bandwidth set to 20kHz 400 lines the frequency resolution is 50 Hz line Title Setting Use the title setting to create a title or heading for printed reports This title will be placed at the top of each FFT report you print You are allotted 30 characters Printing of FFT reports is not currently available Gain Setting The gain setting sets the measuring range of the instrument in 10 dB steps by adjusting the amplification of the microphone signal This setting provides the following options 20 10 0 10 20 30 40 50 Bandwidth The frequency range of a baseband FFT analysis extends upwards from zero to a selected maximum frequency Thus the bandwidth or the frequency range covered by the analysis can range from a maximum of 20kHz to a minimum of 200Hz This setting provides the following options 200Hz 500Hz 1kHz 2kHz 5kHz 10kHz 20kHz The following table shows resolution and FFT calculation times as a function of the frequency bandwidth Bandwidth Hz 200 0 te ee Resolution Hz line Calcuation Time Seconds 0 5 1 25 2 5 5 12 5 25 0 50 0 20 0 10 0 05 0 02 0 01 9 29 09 FFT Optional 12 3 The 824 FFT
136. are given an address based on their serial number from 1 to 100 Serial numbers that end with two zeros will be addressed as 100 The addresses are sent as a single byte ranging in value from 129 to 228 representing address 1 to 100 respectively address plus 128 while addresses 101 through 127 are reserved At power on all 824s are address enabled as if they had just received their address Whenever an address byte is received only the corresponding instrument is enabled to receive and respond to commands A broadcast command can be sent By sending an address of zero CHR 128 all units on the chain will become addressed and accept the commands that follow Only the device with an address of 1 will respond to the commands This will allow all units to be started at the same moment or to have the same setting sent to all devices with one command i e set all clocks to the current time 9 29 09 824 Network Addressing Commands NOTE Hexidecimal notation The dol lar symbol 8 is used to indicate hexi decimal notation Example 1A is the hexidecimal notation for the decimal value of 26 The addressing of multiple 824s on a RS 422 network has been enhanced so as to allow binary data blocks to be sent to the 824 and not be interpreted as address to automatically identify all 824s on the network and to control the baud rate from the computer more easily The command details follow Command Descri
137. are stored in the EXCD History If an event is discarded because it was shorter than the minimum duration then it will not be included in these values R70 LOG Background Leq nnn n dB R86 ALL Battery Level nnn R87 ALL Battery Source INT EXT ccc R88 ALL Temperature nnn n R89 ALL Serial Number 90 ALL Firmware Rev amp Rev Date n nnn ddmmmyyyy R91 ALL Free Memory nnnnnnn R92 LOG Number of RUN STOP Records nnnnn R93 LOG Number of EXCD Records nnnnn R94 ALL Number of INTV Records nnnnn R95 LOG Number of HIST Records nnnnnnn R96 LOG Number of Daily Records nnnnn R97 LOG Number of Cal Records nnnnn R98 n ALL Error Message List n 1 to 8 1 to the last error If n 0 or omitted then the 8 error codes are output as number nnn nnn nnn A 16 824 Reference Manual 9 29 09 R99 ALL Logic Output 1 State On Off R100 ALL Logic Output 2 State On Off R101 ALL Report Number nnnnn R102 ALL Page Number nnnnn R103 ALL Printer Line Number nnn R104 ALL Calibration Date Time ddmmmyy hh mm ss R105 ALL Cal Check Date Time ddmmmyy hh mm ss R106 ALL Cal Offset nnn n R107 ALL Cal check Level nnn n OFFSET R108 SSA ISM LOG RMS Exceedance Flag 1 R109 SSA ISM LOG RMS Exceedance Flag 2 R110 SSA ISM LOG PEAK Exceedance Flag 2 R111 SSA ISM LOG UWPK Exceedance Flag R112 A
138. area Select or Enter a file to store measurement during download 824 gt l Temp 075ep215 slmdl Save in File name JAT 60 measurement Cancel Save as type SLMDL slmdl Download File hd Press the Save button to return to the download section of the 824 Utility software a 824 Utility ox File View Setups Data Help 5 DBA 2 3 Show Files of Type Active Measurement rooms rta 1 1 Octave Real Time Analyzer ut Start Time 2000 Jul 05 16 19 09 End Time 2000 Jul 05 16 19 23 citi Salt Lake City Utah ity of 37 Note 1 Test performed with relative humidity of 37 Note 2 Air Conditioning turned on Setup Title Select Download Filename Directory CAgreg Filename RT 60 measurement slmdl For Help press F1 9 29 09 824 Reference Manual Adding Notes to a download file Information can be entered into the note fields provided for each measurement The information will be tagged onto the translated reports for each measurements File View Setups Data Help 9 Active Measurement Setup rooms rta Title 1 1 Octave Real Time Analyzer ut Start Time 2000 Jul 05 16 19 09 End Time 2000 Jul 05 16 19 23 raon Lake City Utah i Note 1 Test performed with relative humidity of 37 Note 2 Jair Conditioning turned on Select Dow
139. as mm ss ss hh mm ss or hhhhh mm 824 Reference Manual 9 29 09 Status Status represents the state of the instrument as described at the beginning of this section SPL history graph This shows one second Leq readings The far right bar displays the current SPL readings As readings are taken they are placed onto the scrolling graph from right to left every second The time axis in the SPL history graph shows time increasing from left to right You can use the arrow keys to select the detector weighting secondary parameter to be displayed and gain or range as shown below Key Action Moves to the next setting a Moves to the previous setting or P Adjusts the current setting Detector Weighting Fast Slow Impulse A C or Flat Secondary Parameter Secondary Weighting Gain Leq SEL Lmax Lyk A C or Flat 0 10 20 30 40 50 9 29 09 System 824 Views 5 7 Any Data View The Any Data View presents a tabular display of SLM data in three different formats Any Level Format Any Impl Impulse Format Any Time Format amp W arrow keys allow you to change the Any Data format you are viewing The and D arrow keys move you through each of the Any Data formats available displays Any Level Format In this view five different tables present SPL Fast and Slow Lmax Fast and Slow Lmin Fast and Slow Leg SEL and Lpeak measured with A C and
140. at current filter Filter set by 3 E 4 5 or E 12 E17 LOG Excd Time Hist Samples nnn E17 n RTA Extracts ByTime History and returns nothing E18 n LOG Excd Time History nnn n dB E18 RTA RT60 delta time NOTE Value is determined by prior E 16 or E 17 E19 lt n gt LOG Excd T H Time SSS SS E20 lt n gt LOG Excd T H Number nnn A 58 824 Reference Manual 9 29 09 Instrument Type Commands E21 n LOG Description Excd T H Bargraph Commnet 101 LOG Excd Macro Variables 1 10 25 Macro E102 LOG Excd Macro Time Hist 17 18 Macro Interval History Variables Commands The Interval History is a long duration time history of statistical data It is enabled by Setting 83 Interval Enable No Yes see Settings 83 through 90 The period of the interval is selectable from one second up to 99 hours 59 minutes and 59 seconds 99 59 59 Brackets in the syntax indicate optional characters and operands Syntax Response I nterval var_no Intv_var Examples 11 01Jan1997 01 25 00 1 5 01Jan1997 01 20 00 from 5 previous 11 5 01Jan1997 01 30 00 from 5 after 9 29 09 The time syncing feature can be used to synchronize the interval history records to the instruments real time clock If the Interval Period 15 set to the time shown in the first column below the first interval of each new
141. band A bandpass frequency filter that permits signals to pass through that have a bandwidth based on octaves An octave is a doubling of frequency so the upper cutoff frequency is twice the lower cutoff frequency This filter 1s often further subdivided in 1 3 and 1 12 octaves 3 and 12 bands per octave for finer frequency resolution Instruments with these filters have a sufficient number of them to cover the usual range of frequencies encountered in sound and vibration measurements The frequency chosen to describe the band is that of the center frequency Note table in Frequency Filter Frequency Weighting A special frequency filter that adjusts the amplitude of all parts of the frequency spectrum of the sound or vibration 824 Reference Manual 9 29 09 9 29 09 unlike band pass filters It can be composed of one or more of the following types A Weighting A filter that adjusts the levels of a frequency spectrum in the same way the human ear does when exposed to low levels of sound This weighting is most often used for evaluation of environmental sounds See table below B Weighting A filter that adjusts the levels of a frequency spectrum in the same way the human ear does when exposed to higher levels of sound This weighting is seldom used See table below C Weighting A filter that adjusts the levels of a frequency spectrum in the same way the human ear does when exposed to high levels of sound This weighting is most often use
142. be modified tos demo Tat TA LARM Mo A lock icon in this place indicates a FFT Ser user ID that has been locked so it can aLM amp RTA Re not be modified HFT Ins No letter or an arrow indicates a modifiable User defined ID Highlighting one of the setups in the list displays all of the available settings in the setup dialog box right side of the 10 8 824 Reference Manual 9 29 09 window The setups are organized and grouped similar to the 824 menu structure in the instrument Click on the differ ent tabs to access all of the setup parameters SIMR A Tima History Intervals Timer Advancec Select different tabs to access all of the setup functions Suu id Level Meter Tins amp riayzei Sellis or the pull down selections can be used Parameters can be entered manually gt SLM t Real Tine Analyzer SLM Detecto Slow v Fast Freq Weighting fa Bendaicth ha Peak Weightirg 7 RTA weighting ria lian 7 Uatput Control 2 Modifying and Storing Setups to the 824 NOTE If you change settings in the Utility program to an active setup in the 824 those changes will not take effect in the 82 unless the modified setup is re selected With the 824 Utility software you can make modifications to any of the user defined setups and the system setup For
143. be sufficient battery reserve to preserve the memory once the batteries are drained Also the proper setting is important in terms of the ability of the instrument to accurately estimate the remaining battery life Note The System 8245 smart charging system is designed to detect alkaline batteries prevents accidental charging 9 29 09 To use alkaline batteries or individual NiMH cells remove the battery cover and if installed remove depleted batteries or NiMH battery pack If not already installed insert a battery Terminal Assembly AM814 06 so that it is positioned as shown in Figure 1 8 Insert three AA batteries so that polanties match those indicated in the battery compartment and secure the battery cover Indicate the battery type being used as follows Step 1 Press the key Step 2 Press the D key Step 3 Use the W key to highlight Step 4 Press key to activate the Battery Type menu Step 5 Press V or keys to select the appropriate battery type alkaline or NiMH Step 6 Press the key to enter the selection followed by the key to close the Power menu If the rechargeable LD 010 battery pack is used the setting is overridden and assumed to be NiMH The 824 will automatically detect the presence of the pack so the setting can be left to what would most likely be used if individual cells were to be used instead of the battery pack If alkaline cells are installe
144. combinations of frequency weighting and time weighting Taktmaximal 3 Taktmaximal 5 Slow Fast Slow Fast A v v v v v v v v Flat v v Y v The SLM ISM is the simplest to operate providing the functions of a point and shoot sound level meter with manual data storage The SLM ISM Instrument ID measures the same thirty three sound level parameters as the SLM amp RTA SSA ID but it does not provide frequency spectrum measurement capability However since less digital processing is required the measurement linearity range is 105 dBA permitting the use of a single range for all measurements This ID is designed particularly for noise monitoring applications and provides extensive automatic data storage features The Instrument Type designation LOG represents a Logging sound level meter Like the SLM ISM ID the measurement range is 105 dBA and does not provide frequency spectrum measurement capability Up to thirty six measured sound level parameters can be stored as a Time History record at rates as rapid as 32 samples per second 824 Reference Manual 9 29 09 9 29 09 The following parameters can be logged at user selectable time intervals between 1 second and 99 hours hh mm ss Lmin SEL and Leq 4 3 or Time Weighted Aver age q 4 5 or 6 levels for a selected detector Slow Fast or Impulse and a selected frequency weighting A C or Flat Lyeak level corre
145. converted from the decibel numbers that DNA receives from the 824 to that linear units value To do this you need to know a reference level for the decibel reading that the 824 provides It will change depending on the current calibration offset in the 824 The answers to the next two questions will help you accomplish this calculation FFT Optional 12 17 How can convert decibels dB levels from the FFT option of the 824 into linear units in my spreadsheet There are two ways to calculate the linear units from decibels Method 1 With the FFT instrument in the 824 the data can be outputted to the display in linear values such as g gravity or meters second volts or Pascal The 824 makes this calibration using a setting that the user enters This setting is the sensitivity of the unit relative to 1 volt and entered in dB into the Linear Scale setting for example a 50mv g accelerometer would have a Linear Scale of 20 LOG 1 0 05 or 26 02dB The Linear Unit setting is a text field so that the units may be annunciated as desired The Linear Value is calculated in this way 1 Take the dB reading 2 Subtract off the calibration offset this makes the number bigger since the cal offset is negative 3 Subtract 167 dB from the previous result and the number is now in dB volts 4 Add the Linear Scale setting 5 Divide by 20 6 Take 10 to this power this is the Linear Value Here is an example The calibration offs
146. created each new day A day is defined as 12 00 midnight to 12 00 midnight Date Day Date month and year of the record 824 Reference Manual 9 29 09 Daily c Wind Display If the optional firmware 824 WND is not installed the following message will appear Wind Tach E Hot Available This option may be Purchased Please contact Larson Davis Ln Percentiles The L percentile levels level is that level which is exceeded n percent of the measurement time You can select any six percentile values to be calculated and stored with the daily record The Daily c Wind display consists of 10 major components Display label Record Number Date Duration Average Windspeed Maximum Windspeed Direction of Maximum Windspeed Time of Maximum Windspeed Wind Exceedance Data Windy Threshold Data Date Ww ed i0hp 2002 Record Number p d Average Windspeed y Hua Mind 11 47 21 4 Duration MPH Compass B82z NET Maximum Windspeed sta 721 753 Direction of 02 58 56 Max Windspeed Windy Exceedance Dataw gt 408 11 8 Times Windy Threshold Data 2 9 84 45 x Time of Maximum Windspeed 9 29 09 The following explains each of the display s components Display label This shows the current display for example Daily c Wind Record Number Each Daily record is shown in the order that it occurred The record number indicates the ord
147. dB Arm Time When the Arm Mode is set to Time the Arm Time must expire before the 824 will arm This is also a qualifier for the level settings If the time 1s non zero then the level condition must be met for the specified time before Arm Mode is entered 00 0000 to 99 9975 seconds Arm Samples When the Arm Mode is set to Count Arm Samples is the number of samples that will be taken before the 824 is armed 0 65535 Arm Logic In When the Arm Mode is set to Input the 824 will arm when the state of the Logic In line changes to this level Logic In is sampled 32 times each second Low High 824 Reference Manual 9 29 09 Trigger Settings Menu L indicates the level of the filter specified by the setting 9 29 09 Trigger Source Trigger Mode The 824 triggers and starts recording an Autostore record when Armed and the following conditions are met Now The 824 starts recording an Autostore immedi ately L lt When the level is less than the Trigger Level for Trigger Time then the 824 begins recording an Autos tore e L When the level is equal to the Trigger Level 0 5 dB for Trigger Time then the 824 begins record ing an Autostore e L gt When the level is greater than the Trigger Level for Trigger Time then the 824 begins recording an Autostore Input The 824 starts recording an Autostore when the logic input line
148. dB are only available for condenser microphones See Random Incidence Microphone Correction on page C 24 for the random incidence correction filter 5 response If this field is left blank then no linear value will be displayed See the section Displaying Amplitude in Linear Units on page 12 14 for more details 9 29 09 Transducer e Condenser This indicates that the microphone being used 1s an air condenser type and the 824 will generate the appropriate polarization voltage e Electret This indicates that the microphone being used is an Electret pre polarized microphone The 824 will not generate any polarization voltage Direct This indicates that no microphone is being used and electrical signals are being injected directly into the preamplifier No polarization voltage is generated This is the choice when using an accelerometer as the transducer Random Correction The Random Corr setting gives you the option of turning on a digital filter to provide the correction necessary to provide a random incidence response when measuring with a free field microphone No Random incidence correction is turned off Yes Random incidence correction is turned on NOTE Random incidence correction can be used with the 2540 377B41 and 2551 microphones Linear Units Four characters of text are provided so the user can enter the type of units being used for the measurement It accepts any alphanumeric charac
149. data downloading and translation to ASCII format Introduction 1 9 System 824 Components 248 Condenser Microphone 4 Preamplifier 48 LCD Display Figure 1 1 The System 824 is a convenient hand held sound level meter with a simple user interface The standard System 824 shown in Figure 1 1 includes the following 1 2 diameter condenser microphone Backlit graphic 64 x 128 pixel LCD display e 14 key soft rubber backlit keypad AC DC output control serial and external power connectors shown in figure Figure 1 2 True hand held instrument with sure grip pads 1 10 824 Reference Manual 9 29 09 AC DC Output Connector Control Connector Serial Interface Connector External DC Power Connector Figure 1 2 The System 824 has a series of connectors located at the bottom of the device consisting of an AC and DC output connector control connector serial interface connector and external DC power connector The following is a layout of the control connector which is used to control external devices and receive external wind and control information Ground ogic Output Windspee Wind Direction Input 1 2 Wind Direc Power Logic In 3 4 5 6 Cal Check 7 8119 xt Power Heater Cntrl Figure 1 3 9 pin mini DIN control connector solder view 1 Ground 2 Logic output 0 to 5 volts active high through
150. default T H Period 0 255 seconds 9 multiplied by 1 32s Excd Trigger Level PassBy Excd Time Start Max 9 29 09 Using ID Setting Files 7 55 Advanced Menu Layout 7 56 Daily Daily Enable Yes History No default Daily Ln s Yes No default Define Data Report Yes default Report No Advanced See Advanced Menu below Menu Items Controls See also Control Settings _ SSA LOG on page 7 11 Submenu AC DC Output Available Settings Options AC 1 2 AC 1 DC AC 2 DC AC 2 AC 1 Logic In Mode None Pause Toggle Level Alarm 824 Reference Manual 9 29 09 9 29 09 Menu Items Controls Continued Submenu Logic Out Available Settings Options Off RMS Peak R P Intv RH PH R PH A D R A P A R P A I A R P H A R S Excd Logic Out Time 0 255 sec Logic Out 2 Off RMS Peak R P Intv RH PH R PH A D R A P A R P A I A R P H A R S Excd Logic Out 2 Time 0 255 sec Using ID Setting Files 7 57 Menu Submenu Available Settings Items Options Controls Heater On No Continued Yes E A Cal Tone No Yes Wind Tach Wind Scale 0 015 255 99 See also Wind Units 4 alphanumeric characters LOG and TI i SSA Wind Direction Units Compass 16 ordinates Tach Deg
151. disables the printing of the Peak I histogram report The histogram report contains a histogram of the Peak I levels that have occurred during the overall measurement This setting provides the following two options No The peak I histogram report will not print Yes The peak I histogram report will print The Pk 2 Histogram either enables or disables the printing of the Peak 2 histogram report The histogram report contains a histogram of the Peak 2 levels that have occurred during the overall measurement This setting provides the following two options No The peak 2 histogram report will not print Yes The peak 2 histogram report will print The Intv Report either disables the printing of the interval report or enables either the long or the short version of this report The short interval report contains all the basic measurement parameters for each interval period in a specified range of records The long interval report contains everything the short report contains plus some additional information This setting provides the following three options No The interval report will not print Short The short interval report including Lmax Lmin SEL Leg Pk L overloads and exceedances will print 824 Reference Manual 9 29 09 Long The long interval report including Lmax Lmin SEL Leg Pk I overloads exceedances and six Ln Percentiles will print Hist Report
152. e oes 55 Backup Records een deua ive eet deve eR A 56 Calibration History Variables sss ener enne 66 Character String Settings aiseee ie ee ER ERE enr erede ees 35 Commands heated 8 Daily History Variables essendi nie pe dee ricis 64 Daisy Chain addressing Hei bee dit A 5 Data File Commands eh eet ee re EE opes 79 Entering 33 Error Checking T O iere Re pete e eive Oe RE een 48 BrtorM SSageS eei eset 71 Exceedance History Variables 2 1 20 2 214124222 0 3 00 40 600 60 000000000000 000004000000400000000000 57 Find R cords 56 Group Read Programming 29 Histogram Reports ai ER oU A 44 Histogram Table Variables eere etie eet de eR aede A 68 History Data Variables aeree e E 57 History Records edendo dre ner e RE Ch A 54 Intertace Cables 42 5 unam A 2 Interval History Variables eR eee e em aee e re etant 59 Keyboard Simulation tt Pee Pee ede HN eee et A 80 Ln Query Commands
153. eO F 6 Stabilization Time Following Changes of Environmental Conditions F 6 Electric Field Strength Above 10 0 F 6 Greatest Radio Frequency Emission Levels F 6 Effect of Electrostatic F 7 Greatest Susceptibility to AC Power and Radio Frequency Fields F 7 E F 7 Appendix G Miscellaneous Information G 1 iii xvi Introduction Welcome to the Larson Davis LxT This versatile instrument with graphic display performs the functions of several instruments It puts the combined features of a precision sound level meter and a real time frequency analyzer in the palm of your hand About This Manual This manual has 12 chapters and 5 appendices covering the following topics Chapters 9 29 09 Chapter 1 Introduction Orients the user to the contents of this user manual and the System 824 s features functions and measurement capabilities It also includes instructions on unpacking the System 824 Chapter 2 Overview Provides an overview of the instrument s capabilities and a description of each key along with its function and displays It also includes instructions on working with menus Chapter 3 Front Panel Keys their Functions and Associated Menus Explains the functions associated with each key on the 824 Chapter 4 Quick Start Guides users in the immediate use of the System 824 including how to take measurements understandin
154. each of the display s components Display label This shows the current display for example SLM The display represents both Current and Overall c display Current Overall Lmax reading Displays Lmax or maximum level that occurred and the date and time when it occurred Current Overall Lmin reading Displays Lmin or minimum level that occurred and the date and time when it occurred The Current Overall d SLM or Peaks Display consists of three major components Display label System 824 Views 5 29 Current Overall Flat Weighted Peak e Current Overall C Weighted Peak Current Overall A Weighted Peak The SLM Current d or Peaks display is shown below Display label SLM Curnrent d Flat Weighted Peak 160 FABF C Weighted Peak SABC A Weighted Peak 3 3 5 Peak Hz2Declo92 7 11 85 17 2 9 11 85 17 2 199 11 83 24 Current Overall SLM Display e TWA 5 30 The following information explains each of the display s components Display label Shows the display currently being used for example SLM Current d The display represents both Current d and Overall d display Current Overall Flat Weighted Peak reading Shows the flat weighted value from the System 824 s peak detector along with the date and time that the peak event occurred Current Overall C Weighted Peak reading Shows the
155. eee eee eee e RO A ie e e hee 7 16 Logic Output time OS PIRE E ip tis 7 15 SSA LOG xen em c tr RE ER E e RC s 7 11 CriteriOIr shiver SOROR tU po eO ett ROAM REG nS D 3 sound level eee e Reden n o ets D 3 ees 7 19 Current Criterion e ro eoe coget eerte tte tete tette ea e e s 7 20 Exchange oce REI DE E ER ephedra 7 19 SIUM Vi WS ses tess EE m eines 5 25 tier eee C ER ORE LORD EE ERREUR 7 20 Cursors Arrow Keys eoe te t RN Reo ERE ERES e NN Eb ERE dee ROI 3 2 Customizing usu ipe M 3 38 SSA e RR GREEN CREARE E EAE ERREUR EUER 7 2 D Daily Enable 7 42 History Check ER TERRE Wee 7 78 History Variables sane e a rettet ee 64 lb E 7 42 MAE AP E 5 58 Daisy Chain Addressing iA Ee Heu 5 Data ID PR 3 13 Key a d dee ee ter RENE te 3 13 7 43 SLOTAS Cex mE 2 13 Data Piles icc cick E 10 21 BIERS EU VC RE 3 21 Day Night evel RR ts 5 59 D 4 Deleting p PUE 3 17 individual records ERR Rege Wd MR S REIR Te 3 31 last record ote e Rud eee
156. example in the System setup you can change any of the parameters for the Title Calibration Power Date Time Controls or Modem and then send the modified setup to the 824 To store the modified setup select the Save Setup to 824 menu item from the File menu or click on the Store Setup in 824 button on the tool bar Changing System Settings The Option Settings show what options were purchased for this instrument and can t be changed To purchase an option contact your Larson Davis representative 9 29 09 Using the 824 Utility Software The system selection on the setup list box contains the gen eral settings for the 824 The selections here include Title Options Calibration Power Date and Time Controls and Modem To change one of these settings click on the appro priate tab and enter the changes 10 9 GregRTA Manti 0 27 Manipulating a Setup To change any of the variables for a particular user defined setup select the setup The appropriate setup tab dialog will appear at the right of the setup list box Select the setting you wish to change and enter the new value ci 824 Utility 8 WD System Br SLVLFTA r SLY 8 195 demo FOOMS r FTED A de FTEOB Te TA LARM 10 10 824 Reference Manual 9 29 09 You can also access several setup functions by right clicking on the Setup in the Setup list box The following functions can be
157. facing the sound source Rules 1 Do not use a microphone at frequencies higher than specified by the manufacturer to increase the frequency response choose smaller microphones 2 Choose a microphone for free field or random incidence to minimize the influence of orientation A microphone measures what is there from any direction Most measurements are intended to measure the sound level of a specific source but most microphones are not directional so they measure whatever is there regardless of source Rules 1 When making hand held measurements keep your body at right angles to the direction of the sound you are interested in and hold the meter as far from your body as 824 Reference Manual 9 29 09 Near Field Noise 9 29 09 possible Use a tripod whenever possible 2 Measure the influence of other sources by measuring the background sound level without the source of interest You may have to correct for the background There are two types of near fields the acoustic near field and the geometric near field Acoustic Near Field The distance from a source of sound is less than an acoustic wavelength In the near field the effect of the type of sound source is significant Since the wavelength varies with frequency See the definition of Wavelength the distance will vary with frequency The most common example of a near field is driving an automobile with an open window As you move your ear to the plane of the
158. far field the effect of the type of sound source is negligible Since the wavelength varies with frequency See the definition of Wavelength the distance will vary with frequency To be in the far field for all frequencies measured the lowest frequency should be chosen for determining the distance For example if the lowest frequency is 20 Hz the wavelength at normal temperatures 1s near 56 ft 17 m at 1000 Hz the wavelength is near 1 1 ft 1 3 m See the definition of Acoustic Near Field for the advantages of in the acoustic far field Geometric Far Field The distance from a source of sound is greater than the largest dimension of the sound source In the far field the effect of source geometry is negligible Sound sources often have a variety of specific sources within them such as exhaust and intake noise When in the far field the sources have all merged into one so that measurements made even further away will be no different See the definition of Geometric Near Field for the advantages of being in the geometric far field A sound field that 1s free of reflections This does not mean that the sound is all coming from one direction as is often assumed since the source of sound may be spatially extensive See the definitions of near and far fields for more detail This definition is often used in conjunction with reverberant field The rate at which an oscillating signal completes a complete cycle by returning to the ori
159. feed Syntax Response P rint print_no lt cr gt lt lf gt 9 29 09 Example P1 Data Report is printed to computer P9 1 sets all report enables in setup to No 5177 1 2 sets the Data report Run log and EXCD report enables 5178 1 short to Yes and 5192 1 100 3 begins printing to the computer Syn Instrument Description tax Type PO ISM SSA Tailored Report Formatted from normal setup settings 89 113 LOG RTA P1 ISM SSA Data Report LOG RTA P2 SSA LOG Data amp Histograms P3 SSA LOG Short Full Report Histories with SHORT option P4 SSA LOG Long Full Report Histories with LONG option P9 ISM SSA Report Enables Turned OFF LOG RTA P 10 SSA LOG Select All except Histograms in Unformatted Style P 11 SSA LOG Select including Histograms in Unformatted Style P100 ISM SSA Begin Printing through current I O command channel See X100 Com LOG RTA mand P101 ISM SSA Begin Printing through channel selected by Print Command LOG RTA P999 ISM SSA Abort Printing LOG RTA A 70 824 Reference Manual 9 29 09 X 100 ALL XMODEM Begin Printing same as P100 except through the XMODEM communication protocol Use with UnFormatted Reports to download a file to be viewed a spreadsheet program Also use this to download reports for printing on a computer s printer rather than direc
160. following explains each of the display s components Display label This shows the current display for example Excd b Exceedance Number The Exceedance display shows each exceedance record in the order that it occurred The exceedance number indicates the order of the displayed exceedance in relation to the other exceedance records Exceedance Date Time The Event Date Time shows the time and date that this exceedance occurred Peak I Reading The Peak I Reading shows the Peak I level recorded during this exceedance Peak II Reading The Peak II Reading shows the Peak II level recorded during this exceedance Maximum Reading The Max Reading shows the maximum level recorded during this exceedance The Excd c display consists of six major components Display label Exceedance Number Exceedance Date Time 824 Reference Manual 9 29 09 Maximum Windspeed Direction of Maximum Windspeed Maximum Reading and Directio Display label Wind m Exceedance Date Time 1 1 2002 85 45 22 Maximum Windspeed ax 4 ar Maximum level during excd Hax 91 ide a 2 m Excd Number ampass Excd Time History Display 9 29 09 The following explains each of the display s components Display label This shows the current display for example Wind Exceedance Number The Exceedance display shows each excee
161. greater detail Menu Items Available Settings Options Data Report No Yes Setup Report No Yes SPL Histogram No Yes Pk 1 Histogram No Yes Pk 2 Histogram No Yes Intv Report No Short Long Hist Report No Yes The Data Report setting either enables or disables the printing of the data report The data report contains all the basic measurement parameters for both the overall and current measurements This setting provides the following two options No The data report will not print Yes The data report will print The Setup Report setting either enables or disables the printing of the setup report The setup report shows each of the parameters and how they are set This setting provides the following two options No The data report will not print Yes The data report will print Using ID Setting Files 7 43 SPL Histogram LOG Pk 1 Histogram LOG Pk 2 Histogram LOG Intv Report LOG SSA 7 44 SPL Histogram either enables or disables the printing of the SPL histogram report The histogram report contains a histogram of the SPL levels that have occurred during the overall and current measurements The report also prints a table of all 1 to 99 Ly percentiles This setting provides the following two options No The SPL histogram report will not print Yes The SPL histogram report will print The Pk 1 Histogram setting either enables or
162. horizontal axis Autostore record number Display label gt BT Spectrum P Current ByTime sample number p 247 Filter level in dB Total number of ByTime samples gt 3942 an dEl Selected filter frequency p 160 ByTime sample time 9700 This ByTime display shows that 600 spectra were taken and we are currently looking at record number 597 To move to the ByTime Graph display press the Q check key twice 9 29 09 With the up W down arrow keys you can view each ByTime spectrum sample that was recorded Use the left and D right arrows to move the cursor to look at each individual frequency NOTE Notice as you move through each ByTime sample that the sample time changes A minus sign in front of the time indicates that they are pretrigger samples 0 is the point where the trigger occurred RTA optional 11 29 ByTime Graph The Autostore ByTime Graph display is a time graph of just one filter frequency plotted with time as the horizontal axis This graph is useful in seeing the level rise or fall characteristics of each individual filter Autostore record number Display label gt ByTime sample number PLE ou Filter level in dB 4446 DE Total number of Bytime samples dE sn Horizontal graph scaling Selected filter frequency Sz 0 ByTime sample time
163. indicates the order of the displayed log entry in relation to the other log entries currently in active memory Event Date Time The Event Date Time shows the time and date that this Log entry either started to run or was stopped Run Stop Indicator Each measurement reading log has two entries one corresponding to when the measurement started to run and the other entry corresponding to when the measurement was stopped The Run Stop indicator shows whether the log entry indicates the time and date of a Run log entry or a Stop log entry 9 29 09 System 824 Views 5 41 Time History Display Label SSA Time History RECORD 1 OF HZ iun ian Run i HD Bn bp us Status Indicator Other level 55H Time History RECORD aH OF HZ in ian Pause BD ED With the Time History View you can graphically scroll through and view the SPL readings at different points of time in the measurement readings currently active in memory You can access the Time History display by selecting Time History with the Y Check key from within the main View menu Example Time History displays are shown below Time Cursor SLM Time History 55H Time Historu RECORD 31 RECORD 8 OF gy 120 OF az iuD dE ian 44 07 Stop 7 49 52 an Lmax Marker set at this point in the time history SSA Time History SSA Time Hist amp ru RECORD 24 RECORD oF B3 14D F B3 iun 4120 C
164. instrument or recall a stored Instrument Definition ID Displays the Tools menu Allows you to TOOLS change Calibration Clock Timer Mem ory Lock Power Monitor and Commu nication settings Displays the Print menu Allows you to PRINT change print settings and to print data reports and Snapshots The functions and displays associated with the above keys are described next In addition relevant reference material 15 included for settings and options which may be available for keys on the System 824 keypad The purpose of the POWER key on the System 824 is to turn the power on or off close menus and display the remaining battery life Once the System 824 is turned on pressing the key again will activate a PWR display where you can change screen contrast turn the backlight on or off and adjust power options To turn the instrument off press and hold down the key until prompted to Please release key Release the key and the instrument turns off This section discusses the following Power up the Instrument Viewing PWR Display Power Settings Extra Notes on Power Conservation 9 29 09 Front Panel Keys Functions and Menus 3 3 Power up the Instrument Viewing PWR Display Pressing the 4 key again will return you to the previous display From this display you can adjust the contrast and turn the backlight on or off Pressing the or W key adjusts the contrast P
165. integer value within the following range 0 to 255 dB Exposures at higher sound exposure levels than the overall criterion level will result in a 10096 dose in less time or if exposure continues the overall dose will exceed 100 The following are examples of the System 824 Sound Exposure displays SLH Exposure b eu Hue 1 90 Leg 35 7 dBA 346 SEL 152 4 den Ley 29 1 C A 06 LOG and ISM Measuring Ranges The following table presents the typical RMS detectors measuring ranges for the LOG and ISM instruments Frequency Weighting Range A Flat Low Range 20 108 dB 25 108 dB 25 108 dB Normal Range 23 128 dB 28 128 dB 30 128 dB High Range 43 148 dB 48 148 50 148 dB 9 29 09 System 824 Virtual Instruments 6 9 NOTE Ranges are in dB SPL using a The LOG and ISM instruments have a dynamic range of 105 typical 377B41 microphone with 44 1 dB mV Pa sensitivity See RMS Measurement Range LOG and ISM modes only on page C 11 for more 824 specifications 6 10 824 Reference Manual 9 29 09 Using ID Setting Files The System 824 makes it easy to make the measurements you need through stored instrument definitions ID You can select one of the permanent ID s or you can create your own library using the 824 s keypad or the 824 Utility soft ware This chapter will describe how to recall or activate an ID customize it to su
166. is guaranteed to have no more than 75 overlap The Hanning window is typically used for most measurements 12 4 Avg Count The average count is the number of FFTs taken and averaged together 11016384 FFT Repeat Once the average count is completed you can choose to continue repeating the FFT or have the FFT stop e No Stops the count when the average count has been reached e Yes Repeats the count continuously Window The time weighting window can be the following Rectangular provides finest frequency resolution Hanning good compromise between amplitude accuracy and frequency resolution Most commonly used for general measurements Flat top provides best amplitude accuracy Often used for calibration The Rectangular window provides the best frequency discrimination but can have significant filter leakage or effects of a truncated series The Hanning window minimizes the filter leakage with the cost of a wider main lobe The Flat top window gives better amplitude accuracy in the passband Overload Skip Overload skip allows you to throw away or keep spectra that contain overloaded data No Averages in spectra with overload data Yes Does not average spectra in that contains overloaded data 824 Reference Manual 9 29 09 When a condenser microphone is used the 824 requires a stabilization time of approximately 45 seconds before a measurement can be taken Gains of 20 and 10
167. is logged into memory An illegal exceedance is when Excd Lmax gt RMS Excd Level 2 The phone will also be dialed if the memory is low 824 Reference Manual 9 29 09 Monitor Number The monitor number is used to specifically address the monitor 824 Phone Dialing Procedure The Model 824 dialing process 1s as follows Example 824 sends ATDT 1 555 1234 Enter Modem Enter sends 824A0123 001 2 9 29 09 e Phone The valid characters in Phone are those recog nized by the modem to which the Model 824 is attached and generally include W will wait for another dial tone P selects pulse dialing T selects tone dialing will pause dialing for 2 s space or used to make the number more read able T9W 1 412 555 1212 indicates to use tone dialing dial 9 for an outside line wait until the dial tone Is detected and then dial the number Step 1 Step 2 Step 3 Step 4 The Model 824 recognizes an exceedance or low memory condition The Model 824 asks the modem to dial the phone number The modem informs the Model 824 that a connec tion has been made The Model 824 modifies its baud rate to that of the connected modem If the connection is unsuccessful the procedure is retried in 4 min The Model 824 sends the following announce ment 824 82440123 001 2 enter where 0123 1s the Model 824 s serial number 001 18 A 75 Computer sends
168. label Inter vial 7f iind E 197 1 Interval Number Interval Date Time gt 1 2082 11 68 48 Average Wind Speed p Maximum Wind Speed Md 1 B Bs MED and Direction Compass WUHU Interval Duration 3 Duration 47 31 84 The following explains each of the display s components Display label This shows the current display for example Interval f Wind Interval Number The Interval Number display shows each measurement interval in the order that it occurred The Interval Number indicates the order of the displayed interval in relation to the other interval records Interval Date Time The Interval Date Time shows the date and time that this interval began This display will show Average Windspeed The Average Windspeed is the numerical average of the windspeed over the duration of this Hot Enabled Maximum Windspeed The Maximum Windspeed is the if the interval setting Intv Save maximum instantaneous value of windspeed logged during Lns issetto this interval Interval Direction of Maximum Windspeed The Direction of Maximum Windspeed is the direction of the maximum instantaneous value of windspeed logged during this interval Interval Duration The Interval Duration shows the length of time of the currently displayed interval 9 29 09 System 824 Views 5 51 Exceedance History For further information see sections LOG and SSA Trigge
169. m dB Ala 18B8Hz umm This screen shows the third octave spectrum In this example the measurement is reset and the cursor is placed on the 1000 Hz third octave frequency At this time the instrument should be calibrated manually Press the Tools key 2 use the down arrow key to highlight Calibration press the check key 7 twice use the down arrow key to highlight Change and press the check key Follow the prompts to perform the calibration Please refer to the 824 Reference Manual for information on calibrating the instrument There are three measurement modes for the AUD instrument e SLM RTA used to measure 1 3 octave spectra and broadband weighted SPL FFT used to measure constant bandwidth narrow band spectra with special functions to perform attenuator linearity frequency flatness and harmonic distortion measurements 824 Reference Manual 9 29 09 View Menu SLM RTA Submenu FFT Submenu Pulse FM Submenu 9 29 09 e Pulse FM used to measure pulse and frequency modulation functions of the audiometer The mode is controlled by the display being shown The View menu is divided into three sections for the three modes and can be used to select the display needed for a particular measurement Most of the displays are also grouped together and alternately accessed by pressing the up and down Q arrow keys The structure of the View menu is described below Press the V
170. mid frequency average level is under the defined range for RC Over indicates that Lmf is above the defined range for RC indicates the RC is Neutral e RV indicates the RC Vibration Rumble check failed R indicates the RC Rumble check failed optional 11 41 Rooms HTL The Rooms display is only The Rooms HTL display calculates the Hearing Threshold available when 1 3 octave filters are Level for the spectrum being displayed when Rooms is selected chosen from any spectrum s check menu Display label _w ROOMS HTL Level in dB of selected filter a amp 5 54 120 Selected filter frequency 1500H HTL HTL status 9 Fail The HTL status indicator can show the following Pass indicates the recording environment is suitable to produce recordings without audible background noise Fail indicates the recording environment is NOT suit able to produce recordings without audible background noise 11 42 824 Reference Manual 9 29 09 FFT Optional The FFT option gives the 824 the ability to do narrow band frequency analysis using the Fast Fourier Transform This chapter describes the features and functions of this option Features The FFT option has the following features 400 line FFT 1 Hz to 20 kHz Hanning Flat Top or Rectangular window Bandwidths of 200Hz 500Hz 1kHz
171. n ANSI filter number or 1 for Flat R220 RTA Spatial Averaged sample count nnnnnk R221f RTA Room Spectrum f ANSI filter nnn n number or 1 for Flat R222 f Room Class Spectrum f ANSI fil nnn n ter number or 1 for Flat R223 RTA Room Level SIL or Lmf in dB nnn n R224 RTA Room Data NCB or RC nn R225 RTA Room Flags Over Under Hiss cecce Rumble Vibra R226 n ALL Display the Last history record type 0 Last record type string Date Time of last record ddmmmyyyy hh mm ss 2 Duration Runtime of last rec hhhhh mm hh mm ss mm ss ss 3 Record Size bytes nnnnnnn 4 Instrument type of record ccc R227 TAL Tonal Frequency in Hz nnnnn R228 TAL Tonal delta Frequency in Hz nnnnn R229 TAL Tonal Level nnn n R230 TAL Tonal Group Level nnn n R231 TAL Tonal Background Level nnn n R232 TAL A weight Impulse Leq Overall nnn n R233 TAL Tonality Run Time hh mm ss R233 LOG Excd Duration mmt ss ss R234f 55 Ln 1 Spectrum dB f ANSI filter nnn n number 9 29 09 A 23 R235 f SSA Ln 2 Spectrum dB f ANSI filter nnn n number R236f SSA Ln 3 Spectrum dB f ANSI filter nnn n number R237f SSA Ln 4 Spectrum dB f ANSI filter nnn n number R238 f SSA Ln 5 Spectrum dB f ANSI filter nnn n number R239 f SSA Ln 6 Spectrum dB f ANSI filter nnn n number R240 n SSA Ln percentage stored with the spec nn nn
172. noise floor this will be indicated by a flashing downward 824 Reference Manual 9 29 09 directed arrow in the upper right corner of the display as shown below 69 2214 100 Le ed 80 BB 28 19 8 To avoid this condition select a lower range ISM or LOG Mode are a higher value of Gain SSA Mode Max Min and Peak Values As stated in Editing the Measurement Parameters on page 9 5 Lmax and Lmin are measured for all combinations of frequency weighting A C and Flat and detection Slow Fast and Impulse Peak values are measured for A C and Flat frequency weighting These max values represent the highest value of each which was measured during the measurement time interval and the min values represent the lowest values measured during the same time interval A reset operation will reset these values to the values being measured at the instant the reset operation is activated The nominal range for the measurement of Peak values using A C or Flat weighting are specified in the section Peak Measurement Range LOG and ISM modes only on page C 12 9 29 09 Performing a Sound Level Measurement 9 15 Measuring for a Preset Integration Time Timer Mode The System 824 can perform an integrated measurement over a preset time in either the LOG or SSA Mode by making use of the Interval measurement feature For a detailed description of setting up for an interval measurement see the section
173. of 3dB Dose and Projected Dose Calculations Dose is a measure of Sound Exposure and is defined in ANSI 51 25 Section 4 7 as D Q Ca foe dt 0 T where D Q is the percentage criterion exposure for exchange rate Tc is the criterion sound duration 8 hours T is the measurement duration in hours 9 29 09 B 5 tis the time in hours L is the SLOW or FAST A weighted sound level a func tion of time when the sound level is greater than or equal to L or equals when the A weighted sound level is less than Lt L is the threshold sound level specified by the manufacturer is the criterion sound level specified by the manufacturer Q is the exchange rate in dB and q the parameter that determines the exchange rate where q 10 for a 3dB exchange rate q 5 2 for a 5dB exchange rate q 4 log 2 for a 4dB exchange rate The factor of 100 in the equation produces a result that is a percentage Dose is obtained from the accumulations made for TWA and SEL using the formula where is the current SPL at sample s for measurements that include a threshold Lis is set to x if Lis is less than the Threshold Level 2 w z log log T 115200 log 100 DOSE 10 96 k 1s the exchange rate constant which is equal to 10 00 for an exchange rate of 3dB Leo or Y 3dB log 2 eq 13 29 for an exchange rate of 4dB or 4dB log 2 824 R
174. of sound that can be detected by microphones Not all pressure signals detected by a microphone are sound e g wind noise It is the amplitude of the oscillating sound pressure and is measured in Pascals Pa Newtons per square meter which is a metric equivalent of pounds per square inch To measure sound the oscillating pressure must be separated from the steady barometric pressure with a detector The detector takes out the steady pressure so only the oscillating pressure remains It then squares the pressure takes the time average and then takes the square root this is called rms for root mean square There are several ways this can be done Moving Average The averaging process is continually accepting new data so it is similar to an exponential moving average The equation for it 1s t lr 2 t amp Pas no Qe 5 1 t 8 The sound pressure is squared and multiplied by exponential decay factor so that when the time of integration is near the current time t it is essentially undiminished For times older less than the current time the value is diminished and so becomes less important The rate at which older data are made less influential is expressed by the constant T The larger is it the slower the decay factor reduces and the slower the response of the system to rapid changes These are standardized into three values called Time Weighting See the values below Sound Pressure Level SPL L D 20
175. often Lightning might be the closest thing to it Statistically the confidence can be determined The timing of these pulses will not fall so precisely with the sampling and there are not such narrow impulses that can form this sawtooth waveform so we do not see that much error in reality What is the difference between the Max and Peak level that can be stored in the LD824 s Time History What is the relationship of SPL Leq Max and Peak Answer For further information see Appendix D on page D I and the preceding Question Question 9 Answer G 8 SPL is the instantaneous Slow Fast or Impulse sound pressure level as defined by in the ANSI 51 4 and IEC 651 standards They are true RMS root mean squared levels The detector time constant for Slow is one second and for Fast it is one eighth of a second The detector time constant for the Impulse detector is 35ms with a fixed decay time of about 3dB per second The Leq is the energy average of the waveform encountered during the duration of the time history period The Max level is the maximum SPL obtained for the selected detector during the duration of the time history period The Peak is the instantaneous maximum amplitude of the incoming waveform encountered during the duration of the time history period The peak of a continuous sine wave is 3dB higher than its RMS or SPL value Is 1t possible to control the 824 Run and Stop from an external signal exam
176. one screen to another The data displays available under the key depend on the instrument type used to measure the data These will be described in more detail in later chapters dedicated specifi cally to each instrument type 824 Reference Manual 9 29 09 Data Key If no data files have been saved the Recall option will not be available for recall If the instrument is running when you try to store a Data File you will be prompted to stop the measurement before storing the file To view a data file use the amp or W keys to select the desired data file Each data file is marked with a number and the instrument used e g SLM amp RTA SSA 9 29 09 The ll DATA key controls the storing and recalling of measurements or data files from memory Each file may contain cumulative data time history interval history cali bration data and histogram tables that can be stored as dis tinct measurements from other measurements with their data and histories A list of all stored measurement data is shown and individually recalled by selecting it using the arrow keys and check key To access the Data Files menu press the lh DATA key screen similar to the following appears Data Files Store File IH Recall From this menu you can store data or view and recall stored data To store measurement information into a Data File high light Store File using the amp W keys Pres
177. organization and encourages our customers to be environmentally conscious When this product reaches its end of life please recycle the product through a local recycling center or return the product to PCB Piezotronics Inc Attn Recycling Coordinator 1681 West 820 North Provo Utah USA 84601 1341 where it will be accepted for disposal 824 Reference Manual Chapter 1 Introduction 1 1 About This Manual e eager ere 1 1 Special Features of the Electronic 1 3 Bookmarks r i eiie E ED REDE HEU ORE 1 3 Opening Bookmarks sse eere enne nennen 1 3 Closing Bookmarks eno iHe RR dee cece 1 4 Expanding Bookmarks sss 1 4 Click to Display Page ede ee eee ertet ett nenne 1 5 Return to Previous View 1 5 Links a Oa ent 1 5 Click to Display Page eee edente ets 1 5 About THS Chapter ede eene n PARE SU EEG 1 6 Formatting cosi IR UE HO WERE 1 6 Features e 1 7 Hardware Heatures sie ai aA eset aie ees 1 7 Systemi 824 Componenls dro tere 1 10 System ect feo eto cate Mo dete 1 13 Getting Started ceci e eR TRO ERE VEU RH ERU 1 14 Unpacking Inspection ete tute tette 1 14 LIENS 1 16 Comments concerning the Digital Signal
178. ottiene e dm d ee te e e e oed 1 3 Lankspdt retento tote te tr RR tee Ried iiit dde 1 5 Special Features obedece tene HR ER ERE EH 1 3 Model 831 Technical Reference Manual Index 1 Mark Display Ra e avo ere P RUP dere 7 62 Measuring Ranges ny 6 9 159 c M 6 9 SSA c tabo ri ere rero DU Ptr etel RO ER s 6 4 autc tbid at Mite oie d edi eds mds 3 27 display xh ete e t e ee xo e a Red ce ds 3 27 low fre memory ICON e eau 5 4 ro EEA t o rU RS 3 29 USAR M E 1 Menu scrolling ine trei e RE E COR ER OR 4 13 4 15 Metrics Display T ae UO ek tle ditte eate 5 65 5 69 Microphone guidelines aeta eomm eet b E a aite oltoma ee ebd D 12 What it meas fes 2 3 5 n vet e en e e ER TE E te o NER UR D 13 Microphones MENPIgI E D 13 Contorming ioter e EUSEB iv RH RN SIR C 1 electiet tare i E eR te FE EUER ERROR TEES D 13 USES EE D 13 Modem answering procedure ese IR e edet tede 76 Control Mode 5h e p RR o Pe ite ER ees Er es 74 74 dialing procedure RR adel oe Ree te ie tie i eed 75 2 reeset 3 37 mode control Rn EE OF ec
179. permanent SETUP options Up to 20 demos are available if the instrument is reset press RESET gt Reset Options gt Purge All Data Files Data cannot be stored downloaded or printed but may be viewed on the display You can have as many as 50 custom SETUPs besides the 10 permanent setups 9 29 09 Miscellaneous Information This appendix contains additional information about the 824 in the form of questions and answers How can I delete the Instrument Definitions ID in the Setup menu that are labeled permanent There are ten permanent IDs that come with the 824 that are the factory default settings for the various instruments in the 824 They are there as a starting point from which to make your own Setups and cannot be deleted Modify each one that you need and then save that ID with your own unique name You can however separate the permanent IDs from your own custom IDs with a special ID whose name is all underscore characters Your setup menu could look like this 10 11 12 13 14 15 16 Slow A Fast C My My 5s Hist LM amp RTA LM AudTest demo ROOMS FFT Logging RT60B S S TA LARM T RT60 A Hint SSA SSA SM SSA SM AUD LOG RTA LOG RTA RTA Integrating SIM set to Slow A weighted SPL Integrating SIM set to Fast C weighted SPL Integrating SIM with my personal preferences Customized SSA with my persona
180. polarized microphone The 824 will not generate any polarization voltage Direct This indicates that no microphone is being used and electrical signals are being injected directly into the preamplifier No polarization voltage is generated optional 11 7 By default the RT60 A and RT60 B instruments have Autostore and ByTime enabled See Random Incidence Microphone Correction on page C 24 for the random incidence correction filter 5 response Autostore Settings Menu When a linear detector is selected the store rate is that of the linear detector When an exponential detector is selected samples are stored every exponential detector time multiplied by the exponential store rate Pretrigger samples are only available when the trigger function is used to start the measurement 11 8 824 Reference Manual Random Correction The Random Corr setting gives you the option of turning on a digital filter to provide the correction necessary to provide a random incidence response when measuring with a 2540 or 377 41 free field microphone No Random incidence correction is turned off Yes Random incidence correction is turned on Autostore Turns the Autostore function on or off It allows the 824 to measure and store basic information such as the Leq Max and Min spectra when a measurement is ended by the triggering setup or by pushing the run stop key When Autostore is on ByTime data i
181. same units as the measured parameter For example if we prefer to express acceleration in units of g we may select to represent the acceleration level in decibels relative to 1 ug Using an accelerometer calibrator which excites the accelerometer at an rms amplitude of 1 g such as the PCB 394C06 Portable 1g Handheld Shaker we FFT Optional 12 13 will perform a calibration and calculate that the level we measure should be Lv 20Log o 1 0 1 0 X 105 120 dB Thus prior to performing the calibration using the calibration item in the Tools menu we set the Cal Level to 120 Similarly should we wish to use the same calibrator to measure in units of dB relative to 1 we would set the Cal Level to Lv 20Log o 9 86 1 0 X 10 5 139 9 dB Displaying Amplitude in Linear Units Providing a digital readout of the measured amplitude at the cursor position in linear units When the linear scale is set to zero the 824 will read the rms input voltage Obtaining readout in units of g 12 14 Although the measured level is always displayed in decibels on a logarithmic scale with a digital readout at the cursor position in dB a second digital readout can be created which will show the amplitude in linear units This is particularly useful when using an accelerometer and desiring to readout the amplitude in units such as g m s ft s etc The accuracy of the linear units value wil
182. sequence from unlocked to manual locked to automatic and back to unlocked with the right arrow The left arrow will sequence through the modes in the reverse order AUD Optional 13 11 Manual Lock For manual operation select unlock while at a high amplitude 70dB HL or above where the highest amplitude filter can be detected easily When the correct frequency is displayed press the right arrow to manually lock the filter so that it does not change when measuring low amplitudes inearitu FTH 55 8 i5 Feference 7 308 7 75 58 AGC is not active in the manual unlock or lock modes Automatic Lock For automatic operations select the auto mode by pressing the left or right arrow key until the diamond icon appears as shown below Auto Icon Linearity RTA 0 05 Leve 70 84 A trigger level setting is found on the check menu that defines the amplitude below which the lock is set When above the trigger level the filter frequency will track the highest amplitude signal When the level of that filter drops below the trigger level the lock is activated and the filter 13 12 824 Reference Manual 9 29 09 Linearity RTA Check Menu 9 29 09 frequency is unchanged The icons will show this condition with the lock and diamond icons as shown below Linearity kA 8 1 5 122062 Level Reference 3 398 13 38 Note To change to another filter in auto mode just increase the amplitu
183. set the threshold to 80dB For most community noise measurements set the threshold to OdB When set to 0 all levels are included The Owl Criterion setting sets the TWA level which constitutes 100 dose for the overall measurement The 100 dose occurs if a person is exposed to that level for the criterion time Accordingly this setting can take on any integer value within the following range 824 Reference Manual 9 29 09 Criterion Time LOG Crnt Exchange SSA ISM LOG In the ISM instrument the Crnt Exchange setting is a submenu to the SLM menu selection This setting affects the System 8245 secondary or current buffer 9 29 09 0 to 255 dB Exposures at higher levels than the overall criterion level will result in a 100 dose in less time or if exposure continues the overall dose will exceed 100 The Criterion Time determines how long exposure to the set TWA level can occur before 10096 dose occurs for the overall measurement The Crnt Exchange rate setting sets the exchange rate sometimes called the doubling rate that calculates the current TWA The exchange rate reflects the relationship between the permitted exposure levels and the exposure duration Selecting an exchange rate of 5dB for example means that 5dB may be added to the permissible exposure level every time the exposure duration is cut in half This setting provides the following four options 3dB The Crnt Exchange defaults to the 3
184. sets the desired transducer This setting provides the following three settings Condnsr This indicates that the microphone being used is an air condenser type and the System 824 will generate the appropriate polarization voltage to make it function properly Elctret This indicates that the microphone being used is an electret pre polarized microphone The instrument will not generate any polarization voltage Direct This indicates that no microphone is being used and that electrical signals are being injected directly into the preamp The instrument will not generate any polarization voltage The Random Corr setting gives you the option of turning on a digital filter to provide the correction necessary to provide a random incidence response when measuring with a 2540 or 377B41 free field microphone 824 Reference Manual 9 29 09 See Random Incidence Microphone Correction on page C 24 for the random incidence correction filter 5 response Pk Weighting SSA LOG ISM PK II uses the normal weighting setting RTA Detector Setting SSA 9 29 09 No Random incidence correction is turned off Yes Random incidence correction is turned on NOTE Interval Spectral LNs will not be available when R I Correction is turned on Overall Spectral LNs will only be available when the 824 is stopped This means that the overall Spectral LN data will not be viewable when the 824 is running If you try to view th
185. statistics including Leg 24 Lan CNEL Lea Luwpk Ln s Lmax and Lmin and for each hour of the day the hourly Leq the hourly EXCD L and the resultant Background Leq Menu Items Available Settings Options Daily Enable Yes No Daily Ln s Yes No Daily Enable allows you to store daily data such as listed above This setting provides the following two options Yes Storage of daily history data will occur No Daily data will not be stored Daily Ln s allows you to store six Ln percentiles with the Daily History data This setting provides the following options Yes Storage of daily data for Ln s percentile will occur No Daily Data will not be stored for the Ln s percen tiles Logging SLM Define Report Settings Define Report Settings are also available to the SSA instrument For more details on Reporting see Printing a Report on page 8 1 7 42 Define Report allows you to determine which individual reports will be included in the Tailored report This allows you to tailor the measurements and the reports desired to your requirements 824 Reference Manual 9 29 09 Use the and W keys to move from one setting to the next Then use the D key to change the selected setting The key is used to return to previous menus Data Report LOG SSA Setup Report LOG SSA 9 29 09 The following is a table of the Define Report settings Each setting is described later in
186. that my be coupled into the microphone Set the reference level to the current level by pressing the check key This will open the Linearity RTA check menu shown below Linearit i Set Reference Highlight Set Reference and press the check key Q again The reference can also be set to an absolute level using the Reference Lvl setting on the check menu 13 10 824 Reference Manual 9 29 09 9 29 09 Once the reference has been set the level is shown relative to the reference level as shown below inearity FTH X 0 1 1 3 This display is used to measure the attenuator linearity of an audiometer The highest amplitude fractional octave RTA bin is found and displayed in the lower left corner of the display The chosen reference level is displayed in the lower right corner This display has a manual and an automatic filter lock feature to lock to the desired filter frequency when going to low amplitudes when other noise signals ambient noises or vibrations present in the environment 4may be higher than the signal being output by the audiometer The right and left arrow keys control the lock mode Press right once to manually lock to the current frequency a lock icon will appear Press the left arrow key once to activate the automatic lock mode a diamond shaped icon will appear Auto Icon Linearity 1 1 MR Level Reference 07 848 70 846 The lock mode will step in
187. that the 824 is stopped with no data present If the 824 is already using the SSA ID there will be a gt to the left of it s name on the second menu line 9 29 09 This section provides examples of how to select an instrument ID take a measurement and store the resulting data Whether using the SSA ISM or LOG instrument the SLM is one of the most common functions used in the System 824 The following example explains how to record and store a measurement in the SLM mode of the SSA instrument Step 1 To activate the SLM amp RTA SSA instrument press the O SETUP key A menu similar to the follow ing appears Edit Settings SLM rSn 5LH ISH SSA Logging LOG Quick Start 4 5 When changing from one ID to another you will be prompted to save your data if you have not already saved it If you do not save your data at this point any measurement readings you have taken will be lost If this is your first time using the System 824 and you have not set up any IDS or have not taken any readings that need to be saved select No The bolded SLM text on the SLM view screen indicates that this is the SLM view of the SSA instrument Any of the SSA displays can be active while taking a reading The instrument display shows a running symbol upper right hand corner when the instrument is actively taking measurements 4 6 Step 2 Step 3 Step 4 Step 5 824 Reference Manual
188. the instrument remains inactive i e with no serial interface commands or key presses for the period of time set by the Auto Off Time set ting the instrument will turn off Manual Off No automatic power reduction features are enabled Auto Off Time 0 99 minutes When Auto Off is activated the System 824 powers down in the specified number of minutes of inactiv ity Standby Time 0 99 minutes Time in minutes when Standby Time power save is activated When activated the System 824 screen blanks and the serial port turns off If any key is pressed or if incoming serial activity is detected the instrument will exit Standby Time and become active again Backlight Time 0 99 seconds Time in seconds when the backlight is turned off The backlight is reactivated when any key is pressed Backlight On Off Turns backlight on off LCD Contrast 0 99 The default contrast setting is 66 Adjusts the contrast or viewing angle of the LCD display This is done by pressing either the up or down arrow key The key increases the contrast percentage darkens the display and makes it visible from a higher angle when viewing from the bottom of the instrument key decreases the con trast percentage lightens the display and makes it more visible from a lower angle 9 29 09 Front Panel Keys Functions and Menus 3 7 External Power AC Pwr Battery AC Pw
189. this interval began 5 46 824 Reference Manual 9 29 09 Intervals c Display Lmin Reading The Lmin Reading shows the Lmin for the currently displayed interval Lmax Reading The Lmax Reading shows the Lmax for the currently displayed interval Interval Duration The Interval Duration shows the length of time of the currently displayed interval The Interval c display consists of six major components Display label nterval Number Interval Date Time Lpeak I Reading e Lpeak Reading Interval Duration The Interval c display is shown below for the LOG and SSA instruments Display label Hterval c is Interval Date Time 2 199 11 82 56 Lpeak IReading peak I 108 7 JEF Lpeak II Reading peak II 93 Z Interval Duration Duration 16 24 36 B 4 Interval Number 9 29 09 The following explains each of the display s components Display label This shows the current display for example Interval System 824 Views 5 47 Intervals d Display Interval Number The Interval Number display shows each measurement interval in the order that it occurred The Interval Number indicates the order of the displayed interval in relation to the other interval records Interval Date Time The Event Date Time shows the time and date that this interval began Lpeak I Reading The Lpeak I Reading shows the Lpeak I reading for t
190. to 1t precedes the time string Full resolution including the fractional part of the level is sent if enabled by the M9 1 command With full resolution 2 bytes per level are sent The first byte being the inte ger portion which is the same as described above The second byte is the fractional portion itis converted by subtracting 32 from the byte and then dividing it by 128 to make ita fraction The fractional part is then added to the integer part to form the level Enable IO Error Check Scheme 8205 0 or 2 CR in a row to disable Data File Commands The amp F I O command reads out information about stored data or FILES and has facilities to store and recall files These work conjunction with Advance Backup and Find to navigate through the File records of this history just like Intervals amp 1 FILE NAME amp F2 FILE EXTENSION InstType ccc amp F3 FILE DESCRIPTION CCCCCCCCCCCCCCCCCCCCCCCCCCCCCC amp F4 CURRENT START TIME ddmmyy hh mm ss amp F5 CURRENT END TIME amp F6 OVERALL START TIME ddmmyy hh mm ss ddmmyy hh mm ss amp F7 OVERALL END TIME ddmmyy hh mm ss amp F8 SIZE OF FILE nnnnnnn 9 29 09 amp F101 Read macro amp F variables 1 through 8 amp F102 Recalla FILE into active memory FILE amp F103 Store the current data in active memory to a Keyboard Si
191. tone or not 824 Reference Manual 9 29 09 THD Check Menu Pulse FM Display 9 29 09 If a harmonic is less than 10 dB above the noise floor the level of the harmonic is marked with an asterisk The noise floor is calculated as the maximum of the minimum the two adjacent valleys If one of the harmonic s side bands is higher than the harmonic then the harmonic is marked with an asterisk Press the check key to open the THD check menu This menu contains the following items View FFT View the current FFT spectrum Gain Changes the gain setting of the instrument Generally use OdB gain for levels at 70dB SPL and above and 30dB gain for levels less than 70dB SPL The Auto Gain Control AGC function of the linearity displays step between 0 and 30 dB gain if the gain setting is something other than 0 or 30 the function is inhibited Bandwidth Setting to select the FFT bandwidth choices are include 200 500 1k 2k 5k 10k and 20k Hertz The default is 10kHz If the THD of signals with fundamental frequencies above 2500Hz is to be measure choose a Bandwidth of 20kHz so that the 2nd through 4th harmonics are captured The Pulse FM displays provide measurements to qualify the pulsed amplitude and frequency modulation FM response of an audiometer AUD Optional 13 21 2 pgB indicates that the level ratio 15 greater than 20 dB Pulse FM a Display See Figure 13 1 on page 13 23 for greater
192. translator function in the 824Util program both 1 1 and 1 3 octave data are provided Common Control Settings Control settings are also available from some check menus as discussed later in this chapter The Control settings are available on most System 824 instruments The Control settings are available on most System 824 instruments Control Settings ISM 7 10 The RTA Weighting setting allows you to display an A C or Flat weighted spectrum An overall reset 1s required before this parameter can be changed A Display s an A weighted spectrum C Display s a C weighted spectrum FLT Display s a Flat weighted spectrum The Bandwidth setting provides displaying of either full octave or third octave bandwidth filters for real time frequency analysis This setting has the following two options 1 1 Display s octave band filters 1 3 Display s third octave band filters For the ISM instrument the control settings can be accessed through the Edit Settings menu as the last selectable menu item Controls 824 Reference Manual 9 29 09 Control Settings SSA LOG Use the and W keys to move from one setting to the next Then use the key to change the selected setting The 4 key is used to return to previous menus Triggering for the SSA instrument is for Logic out only If Logic Out is set to RMS the 824 looks at the level set under SPL Lvl 1 See the section LOG and SSA Trigg
193. type and multiply by the number of records expected per day sum these values and this is the number of bytes required per day Divide this value into the amount of available memory in the 824 see Tools Memory display generally about two million and this is the number of days that can be gathered As an example let s assume a job requires monitoring the noise made by trucks coming and going from a factory near a residential area From an initial site survey it is discovered that all trucks are over 65dBA at the boundary of the road and residential property and that there seems to be a truck passing the site every 3 minutes The occupants of the residential area want to know how many trucks are traveling this road and why they are disturbed by more than others The Exceedance Function will be used to detect events over 65dBA and there are 20 events per hour expected or 240 per day 20 events hour time 12 hours day assuming that the plant operations will be reduced during the night Each event is expected to last 20 seconds and the Excd T H rate is 1 sample per second Statistics based on hourly intervals and a one minute time history are desired to identify disturbance patterns The time history will give the A weight Leq normally and we will also get the A Lmax C Leq and C Lmax The following completed worksheet shows the calculations for this example TOTAL Excd Bytes Day mpi mes 3 amp 4 opyt ine 25 os E
194. under range conditions Although the gain setting does not usually appear on the SLM display it can be found by repeatedly pressing either 824 Reference Manual 9 29 09 the or Y key until the highlight is located in the lower right corner of the display as shown below SLH FTA SPL Slow EE NEED BD ED Leq When the gain setting is highlighted this can be changed by repeatedly presssing the 43 W key until the desired value of Gain appears Performing a Measurement 9 29 09 The procedure for performing a measurement is described in the section Performing a Measurement SLM amp RTA SSA on page 2 7 Among the important aspects covered are the following Stop Pause and Erase Functions in section Stop Pause and Back Erase Functions on page 2 8 Changing the Detector of the displayed SPL value in section Changing the detector of the displayed SPL value on page 2 8 Changing the Frequency Weighting of the displayed SPL value in section Changing the frequency weighting of the displayed SPL value on page 2 9 Changing the Displayed Secondary Parameter in section Changing the displayed secondary parameter on page 2 10 Changing the Frequency Weighting of the Displayed Lpeak value in section Changing the frequency weighting of the displayed Lpeak value on page 2 10 Performing a Sound Level Measurement 9 11 Averaging Time 9 12 After reaching equilibrium with the am
195. use the key to step to the next lower number or character value The 4 D Left and Right arrow keys move between data displays to move between characters of a setting being modified and to move through menus Use the arrow key to move from the current menu into a sub menu or to modify a setting Use the arrow key to move out of a set ting to move from a sub menu back to its parent menu or to move back to a previous menu or display The 4 Left and Right arrow keys will also move the vertical cur sor bar within certain measurement displays 9 29 09 Front Panel Keys Functions and Menus 3 11 V Check Key View Key 3 12 The Y key allows you to choose an item from a menu or to confirm the entry of a setting Pressing Y in many displays will bring up a menu from which you can make changes to settings appropriate to that display The display of data on screen of the System 824 is controlled by the 9 VIEW key Each instrument type e g SSA ISM or LOG has its own set of available data displays which are selected using this key When you press the key a menu containing the available data displays will appear The fol lowing example is a View menu for the SSA instrument Intervals Time HistoruG or W keys and Y key allow you to select the desired display While viewing data often more than one display screen is available You can use the 4 arrow keys to move from
196. weight indicator shown just below the db weight icon will show whether that particular weight is under range or near the noise floor Block with Dark background and Light numerals Defines upper and lower limits of linearity range I gt Bar and Play Symbol The instrument is in preview Current SPL and peak levels are displayed but no data is being acquired Animated Hourglass The instrument is stabilizing to ensure accurate measurement Animated Draining Battery The battery is low and the instrument will shut off soon O L The instrument has been overloaded measurement may not be accurate due to an overload condition having occurred some time during the measurement System 824 Views General Views 5 4 Animated shrinking letter M Indicates that less than 10 of memory is available when shown intermittently or out of memory when shown continuously Animated Clock Indicates that the a automatic run stop timer is active Currently overloaded The System 824 presents measurement data in both graphical numerical text formats for easy comprehension This section provides an overview of the basic components of these display views See the Chapter Using ID Setting Files on page 7 1 for detailed descriptions of the available settings contained within any of the System 824 views After you have selected the SLM amp RTA operating mode or instru
197. will be shown Windy Threshold Wind Exceedance Level Windy Hysteresis 9 29 09 Select Yes to enable the Wind Tach function If disabled by selecting No Wind Tach data will not be measured and no corresponding data will be displayed in Views or presented in measurement results Windy is a condition defined by wind speed above a user defined threshold value Since wind can influence the propagation of sound it is useful to note measurements which were made during periods of higher wind levels The threshold level is entered as a number field using the Wind Units defined above The wind exceedance level represents a second threshold level higher than that associated with Windy Most often this 1s defined to be the wind level above which airflow over the microphone generates pressure variations not associated with actual acoustic signals These pseudo sound signals are detected by the microphone producing erroneous results The System 824 can be set to pause sampling of the sound signal when the measured wind levels exceed this level The instrument will also count the number of times the wind exceeds this level To prevent multiple triggering counting of the same Wind exceedance event a hysteresis value may be entered The event is triggered when the wind level goes over the Wind exceedance level but does not become re armed until the level drops below the value of the exceedance level minus the hysteresis value Us
198. window will appear 10 22 824 Reference Manual 9 29 09 Download Lx Checking this box saves the binary file in the 824 Utility p gt Save Binary Data directory or the designated directory m Viewing Options B 2 Launch Viewer of Type a program associated with BF Spreadsheet Cancel a csv file or txt file based on P the radio box selection For C Text multiple file download the first file will be loaded into the viewing program Checking this box will launch Translate the following records Settings SysSettings CalSettings Summary RunStop TimeHistory Histograms Allows selection of only the records you are interested in viewing b gt The download window gives you the following options You can save only the binary data and translate the file later or You can save the binary data and the selected records from the translated file saved as csv or txt launch a spreadsheet or text editor or You can save only the selected records from the trans lated file saved as csv or txt and launch a spreadsheet or text editor Once you have selected the data viewing options click on the OK button to start the download process 9 29 09 Using the 824 Utility Software 10 23 The download status window will appear and report the sta tus of the download Downloading Measur
199. with a letter or number The characters generally used in a name are A to Z 0 to 9 and underscore and dash but may also be amp The allowed characters in names for IDs are compatible with PC filenames The following characters are NOT allowed Fg se ST 824 Reference Manual 9 29 09 Write Protect Delete Write Enable IDs NOTE Within a given active instrument definition ID write protect or delete operations cannot be performed on files that were stored using that same ID In order to protect or delete these files the active ID must be changed For example stored FFT files can be protected or deleted by switching from the FFT ID to an ISM LOG or RTA ID The ID that is active with a gt by it cannot be deleted Permanent IDs marked with a p in the Setup menu cannot be write protected modified or deleted Write protected IDs marked with a locked symbol on the Setup menu cannot be deleted The icon will not be displayed if the currently active ID is being used Also the currently active ID cannot be deleted 9 29 09 After an ID has been created it can be protected or locked or deleted if necessary To do this use the or W keys from the Setup menu to highlight the desired ID Press the 2 TOOLS key and the following screen appears Herite Protect Delete ID To write protect or lock an ID use W keys to highlight Write Prot
200. 0 Inl en RM P 5 19 5 35 Logging SEM e oet eh ten ento eere tet n vetet Rut edes 5 23 ei e ERR ER T E 5 65 other levels zo ERR UR e UR ROSTER EEUU 5 43 Pass BY eie re to et em ee Tr doe 5 67 Rui Log A eese He 5 19 5 40 SEM t d a du ses 5 5 SLM Current NE M 5 25 SEM Overall er rette petere etes et ded Tr e he EU IRE es 5 25 set e e he ok BE 5 21 SSA CER 5 9 SS A Displdysu it RH RN d ds e RV 5 11 SUIS EE 5 37 Time HistoEy 0s Aste o e RC SER NI d at an BER ES 5 42 Wand Tach easet de edat Me 5 69 Virtual Instr metits or RR DET dd RN 6 1 W Wavelength l 1 8 8 D 23 1V XXil Index Model 831 Technical Reference Manual Wavenumber BlOSSaEy zs rete nies pa eite tate ud reb M eet Iba eq bt D 23 Weighting frequency 3c tto eet p et un ive apte n i a BEG eee D 10 23 Weighting Setting n qe 7 6 Wind Tach enables an ee AUR x A hel tef 7 29 Pause epe 7 30 5 5 25 ERE UR E 7 30 pulse trigger voltage s
201. 0 0 0 0 0 0 0 0 0 4 0 6 1600 1585 00 1 0 0 1 0 0 0 1 0 1 0 4 0 6 2000 1995 00 1 2 0 2 0 0 0 2 0 2 0 4 0 6 2500 2512 00 1 3 0 3 0 0 0 3 0 3 0 4 0 6 3150 3162 00 1 2 0 5 0 0 0 5 0 5 0 4 0 6 4000 3981 00 1 0 0 8 0 0 0 8 0 8 0 4 0 6 5000 5012 00 0 5 1 3 0 0 1 3 1 3 0 5 1 0 6300 6310 00 0 1 2 0 0 0 1 9 1 9 0 5 0 7 1 0 1 4 8000 7943 00 1 1 3 0 0 0 2 8 2 8 0 5 1 0 1 0 2 0 10000 10000 00 2 5 4 4 0 0 4 0 4 0 0 7 1 3 1 3 2 7 12500 12590 00 4 3 6 2 0 0 5 4 5 4 1 0 2 0 2 0 4 0 16000 15850 00 6 6 8 5 0 0 6 9 6 9 1 0 3 0 2 0 00 20000 19950 00 9 3 11 2 0 0 8 1 8 1 1 0 4 0 2 0 Flat frequency response for SSA instrument is extended at the low frequency end Correction is enabled C 8 824 Reference Manual when Random Incidence 9 29 09 9 29 09 a 5 8 5 E 824 Infrasound Response Frequency Hz 10 Infrasonic Frequency Response SLM LOG and ISM Mode Specifications Time weighting Slow Fast Impulse TWA and Peak Frequency Weightings A C and Flat see table on page C 7 Dynamic range gt 115 dBA Overload to noise floor Linearity range gt 105 dBA Pulse range gt 108 dBA RMS noise floor lt 16 dBA typical with PRM902 and 377B41 mic Reference range Normal range 0 dB gain Exchange rates 3 4 5 dB Sample rate 48 000 Hz Peak rise t
202. 1 Ln Query Commands 55 0 2 2 0 11 4 33 Entering Settings penin e eite HERR RUE UR TRAE 33 Option Settings oie DER es ae 33 Numeric Settings 5 eese te ce eH hee deren 35 Character String Settings lt ote eH E eee A 35 Template Settings iode e PR E OR be A 36 Setting List eros ht tty ees A 37 Histogram Reports 2 eoi ene e Ra pmo ee e A 44 Tailored Report Rees eem ee p Re HESS 45 Miscellaneous toten 45 Error Checking ec Kahne aie ala ORE A 48 KTA SettingsCommiands tH espe 51 History Records UR t de A 54 Types of constet ee pde e EN HUE A 55 PAV ANCE soin adt tuit aem e sin uti oie tibus ecd A 55 Back p inen vei e RE e E ER Eddy 56 56 History Data Varia bl S e ree reeet aan a aeanoea eene eene nnne 57 Exceedance History Variables 22 57 Interval History Variables I 5 02 59 Daily History Variables 1 0102 64 Run Log Variables SSA ISM LOG 65 Calibration History Variables 2 66 Time History Variables SSA LOG TAL A 67 Time History Variables SSA LOG A 68 Histogram Table Variab
203. 1 114 Response Restore Calibrator Level Here are typical Calibration Offset Levels dB for several accelerometer sensitivities 1111 52 Sensitivity 1mV g10 mV g100 mV gl V g10 V g Cal Offset23 00 dB13 00 dB 7 00 dB 27 00 dB 47 00 dB 12 22 824 Reference Manual 9 29 09 AUD Optional The System 824 precision sound level meter with the 824 AUD firmware option is the heart of the Larson Davis audi ometer calibration system This instrument and its firmware maintain and exceed the performance of previous Model 800B based systems when used with the AUDit software However the System 824 with 824 AUD firmware alone still possesses numerous analysis features useful for audiom eter testing tasks such as Level Frequency Linearity Total harmonic distortion Pulse measurements e Crosstalk Frequency modulation Narrow band broad band and speech noise Some of these tests are slightly more tedious when performed manually The following overview of the 824 AUD instrument should be augmented by familiarizing yourself with the 824 Reference Manual AUD Optional 13 1 Connecting the Test System For performing audiometric calibration measurements connect the components as shown below Audiometer System 824 Audiometer Earphone Artificial Ear icrophone Preamplifier The microphone is threaded into a connection inside the artificial ear and the microphone preamplifier
204. 1 23 Display label P Trigger Status Trigger State gt Stop lampe Filter level in dB 3d9 29 qq Selected filter frequency m 9OUBHz P e Trigger source frequency L 10881 Repeat count p EP ZoGmeeee ed eeeeee Samples gp ee j eeeee No of pretrigger or triggered 1265 lu RA RO 1 ByTime samples Setup Use the W down arrow key tomove The Trigger Setup display shows the trigger settings in an to the Setup display or press the interpretive way Only applicable settings are displayed VIEW key highlight Setup and press the V Check key Shows that triggering is turned on _ h Display label i AH Conditions EET E 8B 2 for 1 8008 seconds Trigger conditions 9 Trig ihe 4 E for 48 8868 seconds End conditions End iene 58 AdE 6 for 2 886 seconds Repeat measurement 2 times Repeat 2 Limes The interpretation of the Trigger Setup display is as follows The 824 will arm when the 1 kHz filter is greater than 80 0 dB for a period of 1 second When the level of the 1 kHz filter drops below 80 0 dB for 0 seconds immediately the 824 is triggered and begins taking a measurement Pressing the V Check key provides The measurement continues until the End condition 18 quick access to
205. 1554 7 10 Bandwidth Setting 854 2 00 2 0 0006000000000000000000000000000000000003 7 10 Common Control Settings essere enne 7 10 Control Settings 5 css ce eee e e pe eie 7 10 Control Settings SSA 2 2 2 120000000000 e 7 11 AC DC Output Settings SSA LOG ISM ssseseeeeene 7 12 Logic Input Setting SSA LOG ISM sss 7 12 Logic Output Setting SSA LOG ISM sss 7 13 Logic Output Time Setting SSA LOG ISM ssseeee 7 15 Logic a Rh etatis ht lette edis 7 16 Logic Output 2 Time Setting 7 16 Heater M 7 16 EX teen euin eee 7 16 Logging SLM TWA Settings ossein e E E enne 7 17 Ovll Exchange LOG eene 7 17 Threshold LOG sese 7 18 OvlIE Criterion LOG ite e eA RR ANTA e 7 18 Criterion Time O A DLE E E A E E EE 7 19 Crnt Exchange SSA ISM LOG sese 7 19 Crnt Threshold SSA ISM 7 20 Cint Criterion LOG rette aee te e eiie 7 20 LOG and SSA Lii Settings een anao ERR ree Re Ts 7 20 Enable Eni eno o e Eee une 7 21 Start AUD 7 21 gg a a Ea a a aE a ESNE Sa E EE EES AERE E E 7 22 Spectral Ln s SS amp only scene est dense i 7 22 LOG and SSA Triggering Settings sse 7 23 SPBL Excd EOG SA e toe tee ie 7 23 iii vi 824 Reference Manual SPL
206. 195 00 0 0 dBA 15 00 0 0 dBA 190 00 0 0 dBA 199 00 0 0 dBA Interval Records History Records Current Any Data Start Time Elapsed Time Leq SEL Peak 28 Jun 2000 Lmax slow 28 Jun 2000 Lmin slow 28 Jun 2000 Lmax fast 28 Jun 2000 Lmin fast 28 Jun 2000 Lmax impulse 28 Jun 2000 Lmin impulse 28 Jun 2000 Spectra Date Disabled Number Interval Records Disabled Number History Records 28 Jun 2000 15 45 51 00 00 12 7 A Weight C Weight 2 dBA 63 8 dBC 3 dBA 74 9 dBC 1 dBA 78 5 dBC 1 46 27 28 Jun 2000 15 45 55 28 Jun 2000 2 dBA 71 7 dBC 2 46 27 28 Jun 2000 15 46 27 28 Jun 2000 4 dBA 62 5 dBC 145 57 28 Jun 2000 15 45 52 28 Jun 2000 4 dBA 69 5 dBC 245357 28 Jun 2000 15 45 55 28 Jun 2000 3 dBA 60 3 dBC 46 29 28 Jun 2000 15 45 52 28 Jun 2000 7 dBA 73 2 dBC 2 45 57 28 Jun 2000 15 45 55 28 Jun 2000 0 dBA 62 8 dBC 1 46 29 28 Jun 2000 15 45 52 28 Jun 2000 Time Run Time 28 Jun 2000 15 45 51 00 00 12 7 Hz Leql 3 Leq1 1 1 3 1 1 1 3 1 1 Hz Leql 3 Leq1 1 Max1 3 1 1 1 3 1 1 H3 OY gt D gt QD OO 1 2 630 35 0 37 2 4 8 53519 800 3227 1000 33 2 36 6 29 9 34 3 1250 TUA 26 2 63 8 1600 26 0 23 2 2000 21753 s 22 9 27 5 2500 25 1 22 1 50 8 3150 24 9 21 8 4000 23 5 4 19 8 25 5 5000 23 5 20 3 39 5 6300 22 3 20 1 8000 22 8 19 8 10000 24 3 20 6 44 9 12500 24 3 2 16000 25 0 2
207. 2 2 20000 24 6 23 9 62 2 33 6 65 9 27 55 5 25 43 5 24 OoOoo0oooooooooooo MOOOOOOOoOOoooooooo gt 1 A w 824 Reference Manual 9 29 09 Viewing a Translated File Within a Spreadsheet Program To view the translated data with a spreadsheet program select the View Data in Spreadsheet menu item from the File menu or the Launch Spreadsheet button on the tool bar When you select the View Data in Spreadsheet menu item the 824 utility program will attempt to launch the program associated with the csv file extension comma separated variables If you have installed a spreadsheet program your Windows system will most likely have this file type linked to that spreadsheet program ST o s S c 52 27 EELS File Edit View Insert Format Tools Data Window Help xi SAY SBE 5 ww ril zb M 9 os 0 2 aria gt 10 B IUE EIE 89 OA Translated 8 Sep 99 23 11 00 File Transl C Program Files Larson Davis 824 Utility 07 Sep21 s slmdl Model Nun 824 Serial Nurr 0271 Firmware F 2 101 Software v 1 61 Name Enter Company Name Descrl Enter Address Line 1 Desci2 Enter Address Line 2 Setup SLM amp RTA ssa Setup Des SLM amp Real Time Analyzer Location Note 1 Note 2 Overall Measurement Start Time L 1 87 0 dBA L 8 33 0 dBA
208. 25 seconds for SSA and infinite for LOG Intv Time Sync LOG SSA 9 29 09 Intv Auto Stop No Yes Intv Threshold 0 to 255 Intv Exchange 3dB 4dB 5dB 6dB Intv Spectrum None SSA only Max Mins Intv Enable enables or disables the automatic storage of interval statistical records This setting provides the following two options No Disables interval storage Yes Enables interval storage NOTE If Intervals are enabled and Interval Ln s are enabled and Ln s are not enabled then Ln s are turned on and the warning Setting Conflict is displayed Intv Period sets the time interval between successive interval storage operations These storage operations continue either until the instrument is stopped or runs out of memory You can set this to any time value in the following range 00 00 01 to 99 59 59 i e one second to 99 hours 59 minutes and 59 seconds Intv Time Sync setting either enables or disables the time interval sync feature When enabled this feature causes the Interval history storage operations to be synchronized with Using ID Setting Files 7 37 Intv Save Ln s LOG SSA Intv Auto Stop LOG SSA NOTE Do not use this feature with the Time Sync feature or you will not get the full time period you desire 7 38 the real time of day clock This synchronization can occur on a 1 5 10 15 20 30 or 60 minute basis The Period setting should also
209. 2kHz 5kHz 10kHz and 20kHz Count averaging 1 to 16384 Snapshot data storage no ByTime autostore Display zoom with a factor of 2 4 or 8 Total Harmonic Distortion e User defined Linear Units Settings Menu The Settings menu for the FFT instrument is accessed from the SETUP key 9 29 09 FFT Optional 12 1 To select the FFT instrument press the SETUP key scroll down to the FFT instrument and press the Check key The FFT display will appear Press the SETUP key again to return to the SETUP menu At the top of the Setup menu Edit Settings will be highlighted Press the Check Q key or the right D arrow key to edit the FFT settings menu NOTE See System 824 Virtual The menu layout of the FFT settings is shown in the table Instruments on page 6 1 for a more below detailed explanation selecting instrument definitions HAE finiti Menu Items Available Settings Options Title User customized text entry 20 10 0 Gain 10 dB 20 30 40 50 200 500 1k 2k 5k 10k 20k Bandwidth Hz Avg Count 1 to 16384 No Repeat Yes Rectngl Window Hanning Fit top No Overload Skip Yes Condnsr Transducer Elctret Direct No Random Corr Yes Linear Units 4 characters of text Linear Scale 128 99 to 127 99 No Auto Snapshot Yes 12 2 824 Reference Manual 9 29 09 Settings Descriptions 20 amp 10 dB gain
210. 3 16 Linearity FFT Check Menu sse 13 17 Flatness EFT Display icis en e e ee ERE Reds 13 18 PAD Display oisi RU inrer te 13 19 THD Check Memb rear te EE t 13 21 P lse EM e E RR SEDE 13 21 Pulse EM a Display ted RI RU e RR 13 22 Pulse EM b Display ie eee eee eee dts 13 24 Pulse FM Check Menu sse eren enne nnne 13 24 Display t e OS is 13 25 EET Check Mem tet Rue ite etd e eee 13 25 Appendix A Serial Port Interface Remote Control A 1 Interface Cables ies dite e eet A 2 Connection to a computer using 006 22 2 00 A 3 Daisy Chain 4 1 5 824 Network Addressing Commands esee 6 Commands acad ee ito eh ERI idle A 8 Remote Control Commands 9 Mode Commands eee ete eee e eee estis A 9 Read Commands Reads out data A 10 DATA READ 55 2 100001010 000000000000 25 824 Reference Manual Other Read Commands rre ipie A 28 Group Read Programming esessesseeeeeeeeeenn rennen 29 Setting Commands sess A 30 Querying Settings uie e tetendit tete itu i tpe Miete 3
211. 3349 65 0 1 0 1 0 1 0 0 0 0 0 30 3548 13 0 1 0 1 0 0 0 1 0 1 0 30 3758 37 0 4 0 4 0 1 0 3 0 3 0 30 3981 07 0 2 0 2 0 2 0 0 0 0 0 35 4216 97 0 0 0 0 0 2 0 2 0 2 0 35 4466 84 0 1 0 1 0 3 0 2 0 2 0 35 4731 51 0 0 0 0 0 3 0 3 0 3 0 35 5011 87 0 4 0 4 0 2 0 2 0 2 0 35 5308 84 0 1 0 1 0 2 0 1 1 0 35 5623 41 0 0 0 0 0 1 0 1 0 1 0 35 5956 62 0 1 0 1 0 1 0 2 0 2 0 35 6309 57 0 3 0 3 0 0 0 3 0 3 0 35 2 824 Reference Manual 9 29 09 0 0 0 Windscreen Free Field Fxpanded 2 Effect of uncertainty Free Field Free Field 2 824 Corrections Frequency Hz 1 Windscreen gt 2 Response Correctons 0 Free Field with Wind dB dB dB Screen 824 Corrections dB 995 dB 6683 4 0 5 0 5 0 2 0 3 0 3 0 35 7079 46 0 1 0 1 0 2 0 3 0 3 0 35 7498 94 0 1 0 1 0 3 0 2 0 2 0 35 7943 28 0 5 0 5 0 5 0 1 0 1 0 40 8413 95 0 2 0 2 0 4 0 2 0 2 0 40 8952 51 0 5 0 5 0 3 0 2 0 2 0 40 9440 61 0 7 0 7 0 5 0 2 0 2 0 40 1000 00 0 7 0 7 0 3 0 5 0 5 0 45 10592 54 0 5 0 5 0 6 0 0 0 0 0 45 11220 18 0 7 0 7 0 4 0 3 0 3 0 45 11885 01 0 7 0 7 0 8 0 1 0 1 0 45 12589 25 0 6 0 6 0 6 0 0 0 0 0 50 13335 21 0 1 0 1 0 6 0 5 0 5 0 50 14125 38 0 3 0 3 0 7 0 4 0 4 0 50 14962 36 0 8 0 8 0 8 0 0 0 0 0 50 15848 93 1 3 1 3 1 0 0 3 0 3 0 60 16788 04 1 2 1 2 1 0 0 2 0 2 0 60 17782 79 0 9 0 9 0 8 0 1 0 1 0 60
212. 4467 7 004 LCAL is stored with these steps for instruments that have firmware version 4 065 or newer Press the TOOLS key Highlight Calibration and press the right arrow key On the Calibration menu scroll to the bottom of the list and highlight Advanced Press the right arrow key to open the Advanced calibration menu Highlight the Secure line and press the check key this will change the Cal Level value setting to a special key value of 224 48 that allow the calibration settings to be entered directly the key is to prevent accidental calibration alteration Highlight the CAL Offset setting line and press the check key Enter the LCAL value calculated above and press the check key Highlight the Secure line again and press the check key this will change the Cal Level value setting back to 114 00 and secure the calibration settings Exit the menu by pressing the power key pressing the left arrow or pressing TOOLS For firmware versions prior to 4 065 the calibration offset LCAL is entered using a computer and the following steps LCAL is then entered via computer by these I O commands using HyperTerminal Command S1 1 Response Overall Reset FFT Optional 12 21 Command S 41 225 48 Response Key unlock the 5227 command Command S227 7 Response Send LCAL enter your LCAL value Command Q227 Response 7 00 Verify LCAL verify your LCAL value Command S 4
213. 5 55 15 4 0 1K Hz Type 1 limits Graph 4 The 824 in normal range with the 377B41 free field microphone showing the corrected random response LD Model 824 Serial 0132 Normalized to 1000 00 8 O xy with Standard Deviation Tested 07 06 99 10 26 22 by Leroy Harbaugh Note PRM902 SN 0224 2541 SN 5636 Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 06 30 99 05 55 15 1K Hz Type 1 limits C 26 824 Reference Manual 9 29 09 Graph 5 The 824 in normal range with the 2551 free field electret microphone showing the uncorrected random response Larson Davis Model 2551 Serial 0099 Normalized to 1000 00Hz 8 0 xy Tested 03 02 01 16 31 06 by James Higley Note Prepolarized Microphone Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 03 01 01 08 20 13 Type 1 limits Graph 6 The 824 in normal range with the 2551 free field electret microphone showing the corrected random response BSWA Model 201 Serial 3710101 Normalized to 1000 00Hz 8 0 xy Tested 03 02 01 16 31 06 by James Higley Note Prepolarized Reference Mic Model 4133 Serial Number 1424039 Tested 03 01 01 08 20 13 4 0 200 Hz Hz 20K Hz Random Type 1 limits
214. 6 fundamental frequencies above 2500Hz is to be measure choose a Bandwidth of 20kHz so that the 2nd through 4th harmonics are captured Window Setting for the FFT window type Choices are Rectangular Hanning and Flat top Hanning 1s required for THD and frequency calculations Weighting Frequency weighting setting for the FFT This setting controls an analog filter prior to analog to digital conversions whereas the RTA SLM and Pulse FM mode use Flat analog weighed electronics and digital filtering The default value is A weighting so that the Linearity FFT display has the greatest noise rejection The Flatness FFT display overrides this setting and forces the electronics to be Flat weighted Note The Linearity FFT display when using A or C weighting should not be used to measure frequency response and is not good to use for absolute amplitude measurement Always zero the display at your reference point and use the relative level to see changes in amplitude relative to that reference Note also that the FFT s A and C weighting filters may have up to 0 2dB variation compared to the FFT Flat weighting due to component variations and tolerance To make absolute or flat weighted measurements ensure that the Weighting setting is set to Flat 824 Reference Manual 9 29 09 APPENDIX Serial Port Interface Remote Control The System 824 is fully controllable remotely via the Serial Port interface Settings and the operat
215. 630 0 03 G Microsoft Office 150 0 41 800 0 03 msaffice 20 0 0 36 1000 0 13 C3 NetMeeting 250 0 27 1250 0 28 2 00 018 0 0m e Norton AntiVirus v n13 ENN nno T 4 For Help press F1 NUM 2 To change the RT60 calculated and displayed parameters go under the View menu item and select Set RT60 Options The following window will appear 10 34 824 Reference Manual 9 29 09 gt ZEE RT60 Measurements Both the 824 instrument and the 824 Utility software round the RT60 values to two decimal places However because the 824 uses logarithmic arithmetic to calculate the RT60 value and the 824 Utility software uses double precision to calculate the value there may be small differences in the values as reported by the 824 instrument and by the 824 Utility software 9 29 09 Using the 824 Utility Software 10 35 10 36 824 Reference Manual 9 29 09 9 29 09 RTA optional Welcome to the System 824 Real Time Analysis Firmware Option This option adds high speed spectral data gathering to the System 824 and will enable you to perform the following measurements Architectural Acoustics On board RT60 analysis Room Criterion Acoustic Impulse Event Analysis Pass by Event analysis The 824 RTA option provides the following features RTA for fast spectral data Performs room acoustics RT60 RC NCB HTL Averages any number of spectra Uses measurement triggering for
216. 8 second 125 ms This is a less commonly used weighting but will detect changes in sound level more rapidly Impulse The time constant is 35ms for the rise and 1 5 seconds 1500 ms for the decay The reason for the double constant is to allow the very short signal to be captured and displayed The oscillatory movement of a mechanical system generally taken to be solid It is used as a broad descriptor of oscillations The distance between peaks of a propagating wave with a well defined frequency It is related to the frequency through the following equation where c is the sound speed and f is the frequency in Hz It has the dimensions of length A number that is related to the wavelength of sound and is used to compare the size of objects relative to the D 23 D 24 wavelength or the time delay in sound propagation It is related to wavelength through the following equation where X is the wavelength c is the sound speed f is the frequency Hz and o 1s the radian frequency It has the dimensions of inverse length 824 Reference Manual 9 29 09 APPENDIX Memory Usage The System 824 has a memory size of 2 MB This is generally more than adequate for measurements performed on a day by day basis However for applications such as noise monitoring where measurements are performed and stored automatically over a period of days or weeks it is important to be able to calculate the rate at which memory
217. 80dB For most community noise measurements set the threshold to OdB The Crnt Criterion sets the TWA level which constitutes 10096 dose for the current measurement The 10096 dose occurs if a person is exposed to that level for the criterion time or full dose hours Accordingly this setting can take on any integer value within the following range 0 to 255 dB Exposures at higher levels than the current criterion level will result in 10096 dose in less time or if exposure continues the current dose will exceed 100 Ln is the SPL which was exceeded n of the time The Ln s are computed from the overall level distribution histogram or each Interval s level histogram The measured and displayed Ln percentage settings may be changed during the measurement The six Ln s are automatically listed in increasing order 824 Reference Manual 9 29 09 Use the and W keys to move from one setting to the next Then use the D key to change the selected setting The 4 key is used to return to previous menus NOTE An Ln percentage of 0 provides Lmax for the Ln level Enable Ln NOTE If Lns are enabled in the SSA instrument then the Back Erase feature is no longer available See the section Pause Back Erase on page 3 10 for information on the Back Erase feature Start Level 9 29 09 The following is a table of the Ly settings Menu Items Available Settings Options Enable Ln SSA No
218. 82440123 11111111 824 sends Ready Step 5 Step 6 Model 824 Answering Procedure Modem sends 2 Modem sends 82440123 001 0 Modem sends 10 enter A 76 Step 1 Step 2 Step 3 Step 4 the monitor number entered and 2 is a flag 1 Alarm 2 Exceedance 4 Low Memory More than one of these can be set at a time in which case x is the sum of all set flags The Model 824 awaits a response code which should be 824A0123 11111111 enter where 0123 is the Model 824 s serial number and 11111111 is the Lock Combination setting 28 which is required whether or not the Model 824 is currently locked If the response is incorrect the announcement is resent Four chances are given to respond correctly A 3 cr sequence will cause the Model 824 to hang up When a correct response is received the Model 824 indicates it is ready to send data when requested with 824 Ready enter The modem informs the Model 824 that a connection has been requested that 15 the phone Is ringing The Model 824 answers the phone The modem informs the Model 824 that a connec tion has been made The Model 824 modifies its baud rate to that of the connected modem If the connection is unsuccessful the procedure is retried in 4 min The Model 824 sends the following announce ment 824 824A0123 001 0 enter where 0123 is the Model 824 s serial number 001 is the monitor number entered and 0 is a flag
219. 860 0077 Windows utility software SWW 824 UTIL 10 foot microphone extension cable 010 3 1 2 diameter windscreen WS001 The 8245 is delivered with the following standard accessories 8245 Pack 3x 1 5 V AA alkaline batteries Alkaline battery terminal assembly AM814 06 Connects individual alkaline batteries when NiMH battery pack is not used 3 1 2 diameter windscreen WS001 The following optional equipment is also available CAL200 Sound Level Calibrator 1000 Hz 94 or 114 dB IEC 942 1988 Class 1 CAL250 Sound Level Calibrator 250 Hz 114 dB 942 1988 Class 1 Microphone extension cables are available in 1 5 6 10 20 25 35 50 66 100 and 200 foot lengths or custom lengths up to 328 feet Direct BNC microphone input adapter ADP005 External Battery Charger PSA024 Used to quick charge the 010 Accelerometer preamplifier for ICP accelerometers PRA951 4 provides 4 mA DC current Introduction 1 17 Connecting Internal or External Power The 824 is shipped with a NiMH battery pack installed Using the NiMH Battery Pack For additional battery information refer to the section Power key on page 3 3 For detailed information on charging NiMH batteries refer to the section Power Settings on page 3 6 If power is supplied with the AC Power adapter the NiMH or alkaline batteries do not require removal and will power the unit if the AC power adapter
220. 8pF 4 t 5 capacitor The Larson Davis 005 is used for this purpose The ADP005 can be used for noise floor testing by attaching the included short on the front of the 005 The inherent Noise on the low range in ISM mode or 50 dB gain in SSA mode Frequency Weighting Total Noise Electrical Noise A 16 7 C 19 13 Flat 24 21 F 5 Maximum Sound Pressure Level Power Supply Voltage Range Display Device Stabilization Time Following Changes of Environmental Conditions Electric Field Strength Above 10 V m Greatest Radio Frequency Emission Levels NOTE For the specification of emission of and susceptibility to radio frequency fields the System 824 is classified as group X sound level meter F 6 Combination of electronic and thermal noise of the microphone at 20 C measured in a sealed cavity and vibration isolated 2 Electronic noise of the instrument with an ADP005 adaptor in place of the microphone The highest sound pressure level the Larson Davis 824 1s designed to accommodate at the level of overload is 128 dB The peak to peak voltage at this level is 6 25 Vpp input through the ADPO005 The battery power supply voltage range for which the System 824 conforms to this standard is 2 3 to 4 8 volts The System 824 will shut down if the battery is below 2 3 volts when used with alkaline batteries and below 3 3 volts when used with NiMH batteries The disp
221. 9 09 There may be more items in a menu than can be shown in a single display To the right of any menu window there will be a vertical window within which there will be vertical bar If this vertical bar extends from the top to the bottom of the vertical window then all items in the list are shown in the display If the vertical bar does not cover the length of the vertical window this means that there are more items than can be displayed and that those presently being displayed fall within the portion of the vertical window covered by the vertical bar In the example of the Setup Menu it can be seen that there are more items than can be shown one display and that those presently being displayed are at the top of the list Use the up and W arrows to scroll through the list and note how the vertical bar moves to indicate which portion of the list of menu items is presently being displayed indicates that there are more Edit Settings iii lines in this menu ELA 555A gt RTA In the list of available IDs those with a to the left of the name are permanent IDs provided upon delivery These can be selected modified and used for a measurement but the name must be changed when the modified ID is stored so that it does not conflict with the names of any permanent IDs Quick Start 4 15 ep Edit Setti ings 2 HOLNARTA SSA SSA indicates Tom amp liuu pm permanent ID
222. A Live Display shown below BLM R TA_Live The right and left arrow keys control the filter cursor 824 Reference Manual 9 29 09 SLM RTA Live Check Menu 9 29 09 The check menu accessed by pressing the check key while this display 18 active provides the setting choices shown in the next two screen shots 1 Bandwidth RTA Heighting CA 1l The SLM RTA Live check menu items are Graph Allows control over the resolution and scaling of the spectrum graph Gain Changes the gain setting of the instrument Generally use OdB gain for levels at 70dB SPL and above and 30dB gain for levels less than 70dB SPL The Auto Gain Control AGC function of the linearity displays step between 0 and 30 dB gain if the gain setting is something other than 0 or 30 the AGC function is inhibited RTA Detector This setting controls the rate of change of RTA filter output Slow or Fast which provides 1 second or 1 8th second exponential time constants respectively Bandwidth The fractional octave bandwidth of 1 1 or 1 3 are selected with this setting RTA Weighting This setting selects either A C or Flat frequency weighting as a filter prior to fractional octave filtering To measure the level in dB re 20 micro Pascals place the cursor on the frequency of interest and read the frequency and value on the left hand side of the screen Levels must be AUD Optional 13 7 Several different linearity
223. AM TABLE x RESOL 512 LOG PEAK I HISTOGRAM TABLE x 5113 LOG PEAK I HISTOGRAM TABLE LOW n VALUE 5114 LOG PEAK I HISTOGRAM TABLE HI n VALUE A 44 824 Reference Manual 9 29 09 5115 LOG PEAK I HISTOGRAM TABLE x RESOL Tailored Report 816 EXCD REPORT S117 SSA ISM INTV REPORT LOG 5118 LOG HIST REPORT S119 LOG DAILY NOISE REPORT 8120 142 Reserved settings Miscellaneous 5143 AUD Audiometric Calibrator Mode SLM RTA FFT Pulse FM S144 FFT FFT Lines 100 200 400 5145 AUD FFT FFT Bandwidth 200 to 20KHz S146 FFT FFT Averaging Count 1 to 65535 5147 AUD FFT FFT Window Type Rectangular Hanning S148 SSA RTA RTA Gain Range control for SLM FFT AUD instruments 20 10 0 10 INT 20 30 40 50 S149 SSA AUD RTA Detector Rate Slow Fast 5150 SSA ISM RTA BANDWIDTH 1 1 1 3 AUD SI51 ALL Number of Allocated RAM Slots 152 ALL ELECTROSTATIC ACTUATOR OFF ON 9 29 09 A 45 5153 ALL HEATER LINE OFF ON 5154 ALL MODEM MODE 5155 ALL MODEM DIAL OUT MODE 5156 ALL MODEM PHONE NUMBER 8157 ALL Monitor Number 5158 ALL MODEM INIT STRING Special Functions Advanced use only Remaining commands are not available on SETUP menu
224. Any Wght ddmmmyy hh mm ss and Time R25 w SSA ISM LOG Current Pk Level Any Wght nnn n dB R26 w SSA ISM LOG Current Lpk Date Any Wght ddmmmyy hh mm ss and Time 163 SSA ISM LOG TAKT 3 Any Wght nnn n dB Dect 164 SSA ISM LOG TAKTS Any Wght nnn n dB Dect A 26 824 Reference Manual 9 29 09 Where indicates a number to represent combination of weighting and detector which has these values If x is not provided or it is zero then the value indicated by the Wght and Detc settings 1s given NOTE Impulse detector is not applica ble for Takt levels Where w indicates a number to represent the weighting which has these values Detector is not applicable for these measurements 9 29 09 1 A weight Slow detector 2 A weight Fast detector 3 A weight Impl detector 4 C weight Slow detector 5 C weight Fast detector 6 C weight Impl detector 7 Flat weight Slow detector 8 Flat weight Fast detector 9 Flat weight Impl detector A weight C weight Flat weight A 27 If w is not provided or it is zero then the value indicated by the Wght settings Is given Other Read Commands Other read commands are macro commands that send multiple R variables so multiple data can be retrieved from the 824 with one command Other commands O 1 O 2 and O 4 are preprogrammed macros whi
225. B of the noise floor It is also used with NF Compensate Q208 which will place the System 824 in an extended Linearity Range Mode The true noise floor of the entire system must be measured and entered in Q207 This will vary with the selected input weighting or microphone sensitivity An equivalent microphone capacitance can used after calibration to determine the noise floor It may also be possible to remove the microphone bias to obtain this value When properly set up the linearity range can be increased by 10dB NOTE The mode is always turned off with a CAL Change LOG 5208 SSA ISM NOISE FLOOR COMP MODE 5209 Reserved setting 5210 ALL AUX CONTROL REG S211 LOG EXCD RECORD NUMBER 9 29 09 A 49 5212 SSA ISM INTV RECORD NUMBER LOG RTA 8213 LOG HIST RECORD NUMBER 5213 BYTIME HISTORY RECORD NNNNN 5214 LOG RUN LOG RECORD NUMBER 5215 LOG DAILY RECORD NUMBER 5216 LOG CALIBRATION RECORD NUMBER 8217 LOG HISTOGRAM TABLE LEVEL 5218 ALL Data File Record Number 5219 ALL Graph Vertical Scale dB per pixel 5220 ALL Graph Base Level range from 99 to 999 5221 ALL Request to send Output Control Mode 5224 LOG Start Level nn for Ln and EXTH 5227 ALL OVERALL CALIBRATION OFFSET uses 225 48 lock 5230 ALL BIAS OFFSET For High Range Cali bration uses 225 48 lock 5231 Reserved setting
226. BD af ED bb H Em bb Bm a a H i 2 F MPH zm Compass 2p 2m Intervals The and lt arrow keys show different intervals in history The and D arrow keys cycle you through the different Interval screens Intervals a Display 5 44 The Intervals view shows a record of various sound pressure data gathered in time segments over a set period of time An example would be a measurement where data is gathered in one hour time intervals over a 24 hour period You can access the Intervals view display by selecting Intervals with the Check key from within the main View menu The Interval a display consists of six major components Display label Interval Number Interval Date Time 824 Reference Manual 9 29 09 Leq Reading SEL Reading Interval Duration The Interval a display is shown below for the LOG and SSA instruments Display label Interval a 1 Interval Date Time 1997 11 82 55 Reading Leq 56 Z SEL Reading SEL 86 1 Interval Duration Duration 16 24 96 B Interval Number 9 29 09 The following explains each of the display s components Display label This shows the current display for example Interval a Interval Number The Interval display shows each measurement interval in the order that it occurred The Interval Number i
227. DE I RR RS tem v E RR GT HERE 7 7 E 7 1 Detector L M 7 9 RIA Weightlng erret e erdt Or e des 7 10 Separating permanent from custom ssssessesesseseeeeeeenen ener G 1 Set ngs Descriptions nest ea Idee bent e at assise gece ee 7 4 SSA Menu Layout ee cedere vetet een espe te cree eoe hh Pe due e LE tu o ee Ue de 7 45 Talde Symbol cic ce eae tenet te de Uia 4 14 Title Setting USD GR ee diu 7 5 Transd cer Settnp edet aeo eee Dru on mes e a ets 7 8 Weighting Setting n RD Re eet reed E tete qe acri eh 7 6 IEC61672 1 Testingoc o EE RU NR ER re eie IR ARES F 1 Model 831 Technical Reference Manual Index 1 Input Electricalbsz iiis tof tociens tiis inae me F 5 Instrument Definitions Delete zie tate ote tae eoo pntat e ATE 2 2 EET gno mere ete e ee eid 12 1 Eogeging EOC aco ack Semis esheets kale he ees peeked ieee etn dra edet 2 4 ele del ees ed Mis Bede 3 16 Rooms RTA 11 2 60 irre E ri pu 11 17 SEM 2 4 SEM amp RTA SSA tan e P aro NR DRE Ho LOU GS 2 2 MSY POSE EE IET 2 2 Write Enable ce
228. Due to the complex digital processing necessary to perform simultaneous sound level measurements and spectrum analysis the measurement range in this mode is reduced to 80 dBA The design of the System 824 permits the simultaneous measurement of the following sound level parameters a feature we call Any Data Flat Y v v v v v v v v v v Note The detector used to create Leq is a pure integrating true RMS detector which integrates the energy over a specific period of time It may be as short as 1 32 second in a time history which may be as long as 24 hours As a result it does not include decay artifacts of older instruments that integrate the output of the SLOW or FAST detectors 9 29 09 Peak Sound Pressure Level Ly44 with A C and Flat weighting Equivalent Continuous Sound Pressure Level Lq with A C and Flat weighting A time history record can be enabled to capture samples at periods as short as 1 8th of a second Spectral Analysis with Time History Record allows you to record spectral data along with the 33 sound level parameters mentioned above Overview 2 3 SLM ISM Logging LOG 2 4 An interval history which includes 6 L values 6 values with 0 1 dB resolution based on user selected percentages with 0 01 resolution For Takt users as a no cost option the following additional parameters are provided Taktmaximal with the following
229. E If set below 5 seconds the output will remain ON as long as the conditions are true and turn OFF x seconds 0 to 5 after the condition if set to 6 seconds or greater the output will stay for at least 5 seconds but will turn OFF as soon as the condition becomes false or the condition has lasted the number of set seconds i e 0 5 minimum time 6 255 maximum time Logic Output 2 NOTE When Logic Out 2 is not off then the Heater Control setting has no effect It is overridden by Logic Out 2 Logic Output 2 Time Setting Heater On E A Cal Tone 7 16 Logic Out 2 works the same as Logic Output and has the same options as shown above The Logic Output 2 Time sets the number of seconds that the output will remain turned ON following a triggering event See Logic Output Time setting above The Heater Control output selects the functionality of pin 8 of the control connector It is an open drain output such that when asserted the Heater output sinks current to ground when unasserted no current flows It has a maximum rating of 40 volts The Heater setting provides the following options No Is unasserted which is considered OFF line can be used as Logic output 2 Yes Is asserted which is considered ON The A Cal Tone setting is used to manually control the Electrostatic Actuator E A of an outdoor microphone system It is a CMOS output that drives from 0 to
230. E VI 2 ee e tete eed eer e rre etd 7 23 TE WACEC E D 22 U Unenabled IDs Demo Mode rendi eder TR RUE ER E e eed 2 6 Model 831 Technical Reference Manual Index 1V XXi Unpacking and Inspection rics eie tede eed mte etd 1 14 Unsupported Commands ied Sie e re eir ee RE rec 78 Utility Software See 824 Utility V VibratiOns RW E S NR de A tts D 23 3 12 ee ee 2 11 VALLE 5 8 Amy Impulse oerte eate tede a ERI SIRE 5 8 Any Level isset e tede e SERRE US 5 8 Nl 5 9 CHOICES he ett ee eei e to eroe etl ed 2 12 Daily eee ee et het eet M mE 5 58 Daily wind conditions Ma asec Bede re pide 5 61 Daily windy percent sane este nd ee dre aid 5 62 Exce dance History ue ten teet edet n dene te rie stesse ree SE 5 52 Exceedance Time History trie E RIO EUIS 5 55 Exceedance wind conditions ssssseseeeeeeeeeen 5 54 EXPOSURE OA 5 31 Beneral tuere te doter 5 4 Hourly Leq xum xS RR RT Re RR RON detener in 5 63 Marti c E 5 44 Tritervals wind conditions iE eet Reese bax ec t E 5 5
231. Een acts RUE TRE EY ERE Rete cent 2 10 Settings Menu isa dote oet ite tedio e a rote eie tieu 4 18 Check Key oec e nee reae eere a e eie et eie td 3 12 Check Metu RH 7 59 ANY Data ite one en eri a eee eU eere Ense e ELO eos 7 65 Control nete tec TAMEN E POR DR AURA TN GARE 7 65 example een a edad t ade 7 60 Exceedance HIStory i iiio OR EE HSESER EGER V PEE PESOS 7 77 EXpOSUte ri haie a i GER Ee PERDE ET PEERS 7 73 Graph Menu ect ro e er e ee red boi tage 7 64 Intervals Tem Went M 7 67 7 76 Gentiles 7 70 7 74 LOG Any Data rire ee ER an Ree er e ERI CE IE Pe ECCO SERERE eS 7 73 Mark Display ete tette ete tee eter eo t Po Sta s 7 62 Other Logging Check 222050 ERE e ie et 7 73 Othe SSA Check Menus s pU 7 65 te NI n OH teo ed ER i esis wees 7 66 R f L095 oreste estes eet 7 69 7 75 Settings BER E 7 65 SEM Current Overall RE e od e Wades 7 73 SEM Options ic Ree e ER eee ene ac Hae ern ne 7 62 SUAS
232. FT Display FFT Check Menu 9 29 09 Gain Changes the gain setting of the instrument Generally use OdB gain for levels at 70dB SPL and above and 30dB gain for levels less than 70dB SPL High Pass Wght This setting enables the high pass filter section of the A or C weight filters which provide low frequency noise reduction while measuring pulses or FM signals can be set to Flat weighting also The default 18 weighting high pass The FFT display will show the FFT spectrum This display shown below is activated via the VIEW menu Press VIEW key highlight FFT and press check key Q It can also be activated from the THD check menu The right and left arrow keys control the frequency cursor and the up and down arrow keys control the display horizontal zoom feature Press the check key Q to open the FFT check menu This menu contains the following items View THD View the THD of the current FFT spectrum Gain Changes the gain setting of the instrument Generally use OdB gain for levels at 70dB SPL and above and 30dB gain for levels less than 704 SPL The Auto Gain Control AGC function of the linearity displays step between 0 and 30 dB gain if the gain setting is something other than 0 or 30 the function is inhibited Bandwidth Setting to select the FFT bandwidth choices are include 200 500 1k 2k 5k 10k and 20k Hertz The default is 10kHz If the THD of signals with AUD Optional 13 25 13 2
233. Flat weighting as follows nu Level a SPL Fast SPL Slow 4dBF 76 8 5B JJEC Any Level b Any Level c Leg SEL Lmax Fast 7H ddBF H2 99 76 3dBC 8A F460 97 4060 37 846A 73 VABA v7 95 4 Any Lewe 1 4 Lmin Fast 4 2 42 BAEC 32 Any Level e SPL Fast Peak 6H 4dBF 124 808 D58 34BC 123 7480 3 7 BdBH 124 6085 Any Impulse Format In this view three different tables present Impulse weighted parameters alongside similar Fast weighted parameters measured with A C and Flat weighting as follows 5 8 824 Reference Manual 9 29 09 Hnu Impl a SPL Fast SPL Impl 66 85 4 63 BdEc g5 3dBC 57 86 Any Impl b Any Impl c Lmax Fast Lmax Impl Lmax Slow Lmax Impl 92 1 9g3 3dBF 86 1dBF 93 38JBF 91 99 93 29 86 142C 934 246C 93 1 94 406A 1idBR 94 406A Any Impl d Takt3 Fast Takt3 Slow 89 R3 4dEF 89 446C 83 446C 9i B4 4 Ang Imple Additional views if TaktS Fast TaktS Slow functionality is enabled 9H 14PF 83 4cBF See page 3 18 gH HdEC 83 6dEC 9 84 4968 Any Time Format Any Time d 51 9 00 Any T ime g 124 SSA Specific Views In this view seven different displays present the level date and time of Lmax Fast
234. Fre nnnnn nn quency R200 AUD Audiometric Test Max Frequency nnnnn nn 9 29 09 A 21 R201 AUD Audiometric Test Min Frequency nnnnn nn R202 AUD Audiometric Test Modulation Fre nnnnn nn quency R203 AUD FFT Live Spectrum Level nnn nn line number l line 0 400 R204 1 AUD FFT Live Spectrum Frequency nnnnn line number 0 400 R205 FFT AUD FFT Live Broadband Level nnn n R206 f SSA RTA Minimum Level per Spectrum nnn n Filter R207 f RTA Live Spectrum f ANSI filter num nnn n ber or 1 for Flat R208 RTA Live Spectrum s Duration S SSSS R209 RTA Live Spectrum s Overload Status Ovid R210 f RTA Leq Spectrum f ANSI filter num nnn n ber or 1 for Flat R211 RTA Leq Spectrum s Duration hhhhh mm hh mm ss mm ss ss 55 5555 R212 RTA Leq Spectrum s Overload Status Ovld R213 f RTA Lmax Spectrum n ANSI filter nnn n number or 1 for Flat R214 f RTA Lmin Spectrum f ANSI filter num nnn n ber or 1 for Flat R215 RTA Trigger State Stop Ready Armed Trigd Ended R216 RTA Pre Trigger Samples nnn R217 RTA Triggered ByTime Samples R218 n Triggering String 1 amp 2 ARM character string 3 amp 4 Ing 5 amp 6 7 Repeat 21 character string 0 all strings A 22 824 Reference Manual 9 29 09 R219 f RTA Spatial Averaged Spectrum nnn
235. History in steps of 1 32 seconds This setting can take on any time value in the following range 1 32 32 32 seconds The Excd Trigger setting enables you to select whether the Exceedance Trigger utilizes the fixed trigger levels or uses a special 10 dB rise then fall Passby trigger This setting provides the following two options Level Enables fixed level triggering PassBy Enables 10 dB Passby triggering The Time allows you to select whether the time reported for the exceedance is the time that it started or the time of the maximum level This setting provides the following two options Start The exceedance time will be logged at the beginning of the exceedance event Max The exceedance time will be logged at the max imum level of the exceedance event This setting will extend an event to be at least as long as the time set mm ss if it is over the threshold for at least the minimum duration NOTE This setting is only available through the serial port using the command 576 see table Setting Commands on page A 30Logging SLM Daily History Settings 7 41 Daily History Settings are only available to the Logging SLM LOG instrument Use the and W keys to move from one setting to the next Then use the key to change the selected setting The key is used to return to previous menus Daily Enable LOG Daily Ln s LOG The Model 824 automatically calculates daily sound
236. Hz EA E WW 126216 20 Graph 6 824 in the YZ plane fitted with the 2540 microphone 1 kHz C 36 824 Reference Manual 9 29 09 Graph 7 824 in the YZ plane fitted with the 2540 microphone 2 kHz Graph 8 824 in the YZ plane fitted with the 2540 microphone 4 kHz 9 29 09 C 37 Graph 9 824 in the YZ plane fitted with the 2540 microphone 8 kHz NY SAN s S 553 a re We 1 SE i at S fe 7 x Graph 10 824 in the YZ plane fitted with the 2540 microphone 12 5 kHz 824 Reference Manual 9 29 09 Graph 11 824 in the XY plane fitted with the 377 41377 41 microphone 1 kHz Graph 12 824 in the XY plane fitted with the 377 41 microphone 2 kHz FC SAna 55 9 29 09 C 39 Graph 13 824 in the XY plane fitted with the 377 41 microphone 4 kHz NN Hi ASST UU Xe x 5 soe Graph 14 824 in the XY plane fitted with the 377B41 microphone 8 kHz y Fa 77 25 BEES pea nmn 77 i S My 78 Ja a 2 A Y 7 lt gt Ze SY X CM i ans RH S t c7 gt 22 54 T ES ALI 455 A S J 1 20 l HI 9 29 09 824 Reference Manual Graph 15 824 in the XY plane fitted with the 377 41 m
237. IEW key to open the View Menu View AUDY Highlighting SLM RTA and pressing the right arrow key 9 will produce SLM RTA Submenu RTA Any 10 LinearituL Highlighting FFT and pressing the right arrow key 0 will produce the FFT Submenu FFT THD L1 Linearitur Flatness Ll Pulse FM has no submenu Pressing he right arrow key will produce the Pulse FM a display screen The display screens associated with these menus will be described in detail in the following sections AUD Optional 13 5 Display Sequence Note The FFT Display mode can be accessed from the VIEW menu or from the THD check menu See FFT Display on page25 for details on this display type SLM RTA Live Display 13 6 The primary displays are grouped together and will cycle through the following in sequence by pressing the down arrow key the up arrow key will sequence these displays in the opposite order SLM RTA Live Any Level a Any Level b Linearity RTA Linearity FFT activated by default when AUD is activated Flatness FFT e THD Pulse FM The SLM RTA Live display provides a display of the real time fractional octave spectrum To access this display press the VIEW key to obtain the display shown below View SLHA RTA O Pulse FH Then select SLM RTA with the up down arrows and press the check key Q This will produce the SLM RT
238. Im C option 2 1 5 2 1 LeqSpedrum tion 66 33 Live Spectrum tion 66 33 Wind Tach option 4 2 Temperature intema to instrument aia 2 1 Extemal Power Voltage option 2 1 Battery Vol ion 2 1 Table E 9 SSA Memory Usage Time History Records 824 Reference Manual 9 29 09 9 29 09 Other Histories and Memory Usage bytes i 20 bytes per record 17 bytes per record 2503 each file 7623 each file SSA File Store with Enable Ln No SSA File Store with Enable Ln Yes Table E 10 SSA Memory Usage Other Histories and Memory Usage E 9 E 10 824 Reference Manual 9 29 09 APPENDIX SLM Testing to IEC61672 1 This chapter presents information for testing the sound level meter function of the System 824 according to IEC61672 1 Section 9 3 These data represent the performance of the instrument when used with the Larson Davis Model 377B41 microphone Reference Sound Pressure 114 dB Level Reference Level Range Mode Reference Level Range ISM Normal SSA 0 dB Gain LOG Normal FFT 0 dB Gain RTA 0 dB Gain AUD 0 dB Gain TAL 0 dB Gain Microphone Reference Point Center of diaphragm of Model 377B41 microphone 9 29 09 FA Average Frequency Response Corrections The following table presents the corrections for the average frequency response of the System 824 using a PRM902 preamplifie
239. Incidence Correction e ERE SEE ERE es Fees 11 8 Repeat Count uer eee eie pa era rec n OU o s 11 14 Reverberation Time eodd EUER DERE EE REIR Gig 11 16 Room Views sie e ARR ER ea E Cae EROR 11 39 ROOMS feet cat coh tete thre Nau cw ted qd terea 11 18 ROOMS NOB ite OD 11 40 Model 831 Technical Reference Manual Index 1V XVil ERE EET 11 41 RT 60 display aie tee Des 11 33 RT60 AJB c RHET USO RN eee d e RC ERR 11 17 haa potes bae ertet tetas esee teh 11 19 R n Logic In iere e RT HR ER Ue 11 14 nete detenta dotata 11 14 Save B PIME scenes Ree e eedem in eet Het OR PUR Te decies 11 9 Settings Descriptions utr etta o Re ed ate Re ete ie E SED UNSERES ORE 11 6 5 11 2 Spacial Average Isla 11 38 Spatial Ave Check Men rto p see Reo WE ERR 11 37 Spatial Average VIeWS 4 ener i o RE RERO T D ER ERU E ER Ue ea 11 35 Title Settitlg osse esed ate ito ats eu eet 11 6 Transducer b ee aeree n ee np pe e een 11 7 Trig LEogle In zou si te tt ete RO Rn te BEEN Ee ERI Te 11 12 Tig Samples RE HER I e RH p EIE URS 11 12 Trigger
240. L Internal RMS detector level nnn nn dB R153 ALL Internal PEAK detector level nnn nn dB A 18 824 Reference Manual 9 29 09 R154 ALL Internal UwPk detector level nnn nn dB R155 ALL Number of Bytes in Keyboard Stack nnn This is used with keyboard simulation to prevent the loss of keys R156 LOG Background Leq Time hhhhh mm ss ss R157 ALL Calibration Status Done Wait Waiting Stable Unstable Too High Too Low R158 ALL Total Memory Available nnnnnn R159 ALL Memory Available in percent nnn nn R160 ALL OVERALL OVERLOAD FLAG c R161 RTA Number of RTA Records nnnnn R162 LOG Overall Sound Exposure nnnnn n 9 29 09 Sound Exposure E is calculated and displayed in pascal squared hours as needed in some of the European Countries This value is read with the R162 command and is available in the top line of the DOSE a display The formula used is E T 10 Leg 10 20pPa where E is the Exposure T is the elapsed time in hours and 20uP is the reference sound pressure 20 micro pascal squared TAL RTA AUD fis ANSI filter R163 x SSA ISM TAKT 3 nnn n dB LOG R164 x SSA ISM TAKT 5 nnn n dB LOG R165 LOG PassBy Time of Occurrence ddmmmyy hh mm ss R166 LOG PassBy Event Duration hh mm ss mm ss ss R167 LOG PassBy Lmax nnn n R168 LOG PassBy Leq nnn n R169 LOG PassBy SEL nnn n R170 ALL Exte
241. LL System Overload Flag R113 LOG Exchange Rate Text cecce R114 LOG Intv Exchange Rate Text R115 ALL Auto Advance History Indicator R116 ALL Current Wind Speed Frequency or nnn n or nnnnn Tach R132 LOG Today s Minimum Level nnn n dB R 133 LOG Today s Maximum Level nnn n dB R 134 LOG Today s Peak Level nnn n dB R135 LOG Today s UWPk Level nnn n dB R136 LOG Today s Runtime hh mm ss mm ss ss R137 SSA LOG Next Alarm Time hh mm 9 29 09 R138 SSA LOG Interval Date and Time of Occur ddmmmyy hh mm ss rence R139 SSA LOG Interval Duration hh mm ss mm ss ss R140 SSA LOG Interval Lint nnn n dB R141 SSA LOG Interval SEL nnn n dB R142 SSA LOG Interval Lmin nnn n dB R143 SSA LOG Interval Lmax nnn n dB R144 SSA LOG Interval Lpeak nnn n dB R145 SSA LOG Interval UnWeighted Peak nnn n dB R146 SSA LOG AUTO SEND HISTORY LEQ nnn n dB R150 ALL Number of RUNS amp CONTINUES nnnnn R151 ALL Power On Fault Cause Character c D Data Checksum Corrupt E EEPROM Checksum Corrupt K Key Reset 1 v P setting Checksum Corrupt O Opcode Error R RAM Setup Register Corrupt T Test Memory Corrupt W Watchdog Reset An indicator has been added to the ON display on the top line of the 8245 display to show faults that were detected by the power on test procedure The 151 command will display the fault character to a computer R152 AL
242. LOG RTA Print prints the report SSA ISM LOG RTA Depending your printer configuration you may have to modify the Printer Settings for Printer Baud Rate and Flow Control 9 29 09 Step 3 Usethe 43 and W arrow keys to highlight Set tings then press the arrow key or Check key to select it The following menu appears Type Printer CASCIIJ Printer Baud 56801 Flow Control Use the table below to set up the printer settings by using the and W arrow keys to highlight Printer Type Printer Baud and Flow Control and then press the D Check key to select the correct option for each Menu Item Options Printer Type ASCII Epson IBM HPJet HPLzr Printer Baud 300 1200 2400 28800 57600 115 K 9600 19200 Flow Control None Hdwr XOff Both Printing a Report 8 3 Step 4 Use the 4 arrow key to return to the main Print menu You will notice that there is a paper page icon next to the Summary menu item This means that a report will be printed by highlighting Summary and pressing the Check Y key ll Settings gt Summary Recall Format The title printed on your report will Step 5 Your Report will now begin printing and the Sta correspond to the Title setting you tus screen will appear have configured in the Setup menu for the sel
243. Lower Level Report Settings Description Unformatted No A dump of all Read Query and Interval remote commands Multiple values are comma delimited Data Report No This shows general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Setup Report No Print the settings and their values for the SSA instrument Intv Report No Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in the short report The Long reports adds the Ln values and Spectral LNs for the Interval period Hist Report No Leq for each time history period Print Range Intv Report No You can customize the interval report by choosing the long or short report Lowest Record 00000 Selects the lowest interval record to be printed Highest Record 65535 Selects the highest interval record to be printed Hist Report No You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time history record to be printed Highest Record 799999 Selects the highest time history record to be printed 8 20 824 Reference Manual 9 29 09 None Enabled Report Template SSA instrument Histograms SPL Histogram No Prints SPL histogram and overall Spectral LN report Lowest Level 045 Selects the lowest SPL histogram level to be printed Highest Level
244. M amp RTA SSA In the Ln menu set the following settings to Yes and Interval Enable Ln Yes Spectral LN Interval In the Interval menu set the following settings to Yes Intv Enable Yes Intv Save Ln s Yes 5 14 In the Leq Max and Min interval displays the cursor position the vertical bar in the graph corresponds to the SPL level and frequency values on the left side of the display The and down W arrow keys change the record you are viewing In the Leq By Time display the up and down W arrow keys change the frequency displayed For each frequency the level is shown over time for each interval period The right D and left 4 arrow keys move you to the next and previous interval record Interval Spectral LNs can also be selected for each interval period Six Ln values are shown for each frequency Also there are six graphical displays showing spectra for each of the six Ln values In order to turn on the Spectral Lns for the interval period go to the SSA settings menu and select Interval for the Spectra Ln setting under the Ln menu To view the Interval Spectral LN displays press the View key and highlight Intervals 824 Reference Manual 9 29 09 Press the right arrow key to access the Interval display menu and highlight Ln Spectrum Interval spectral LNs are only available when the LOG option is Intervals installed Pres
245. Menu End Then After the measurement ends the 824 may do the following Stop The measurement ends Repeat The measurement repeats when the Arm and Trigger settings have been satisfied A new Autostore record is created for each repeated measurement Repeat Averaging requires the End Average The measurement repeats like repeat above Mode to be set to Time or Count so except that the spectra are averaged with the preceding that all records are the same length spectra Repeat Count Allows the user to select how many times the measurement will repeat when the End Then setting is set to Repeat 0 255 Average Count This is the number of times the measurement is repeated and averaged when the End Then setting is set to Average 0 9 Trigger Settings Menu continued Run on Input When set to Yes the instrument will run when the logic input line changes to the Run Logic In state No Yes Run Logic In Low 11 14 824 Reference Manual 9 29 09 These lines can be used to control lights in a remote control device to indicate the current state High Logic Out The Logic Out bit value determines which lines heater cal or logic will be used on the control connector to indicate each of the five states 0 65535 The setting for the Output Logic state selection is combined into one 15 bit setting that has 3 bits one for each output line Logic Out Heater Out and Cal Out for each ofthe fi
246. Model 824 Precision Sound Level Meter amp Real Time Analyzer Reference Manual 9 ARSON DAVIS A PCB PIEZOTRONICS DIV Larson Davis Model 824 Technical Reference Manual 1824 01 Rev P Copyright Copyright 2006 2007 2008 2009 by PCB Piezotronics Inc This manual is copyrighted with all rights reserved The manual may not be copied in whole or in part for any use without prior written consent of PCB Piezotronics Inc Disclaimer The following paragraph does not apply in any state or country where such statements are not agreeable with local law Even though PCB Piezotronics Inc has reviewed its documentation PCB Piezotronics Inc makes no warranty or representation either expressed or implied with respect to this instrument and documentation its quality performance merchantability or fitness for a particular purpose This documentation is subject to change without notice and should not be construed as a commitment or representation by PCB Piezotronics Inc This publication may contain inaccuracies or typographical errors Piezotronics Inc will periodically update the material for inclusion in new editions Changes and improvements to the information described in this manual may be made at any time Record of Serial Number and Purchase Date Model 824 Serial Number PRM902 Preamplifier Serial Number Microphone Model Serial Number Recycling PCB Piezotronics Inc is an environmentally friendly
247. OG eei dete cito e Td 7 44 Pk 2 Histogram enne 7 44 Intv Report LOG SA sas incide eee dies 7 44 Hist Report LOG SSA henee 7 45 Menu Layout of SSA 7 45 Menu Layout of Integrating SLM ISM Sett ngs eee 7 50 Menu Layout of Logging SLM 7 52 Advanced Menu Layout cecidere e ert 7 56 6 sa hm due ttem da ua utate 7 59 Check Menu Example eser eR ERR RESI es 7 60 SLM Check Menu Options SSA and 7 62 Mark BIS a E uie e tee OT Oe RE RN D 7 62 Graph Men ORE pne ER te En ERE UU 7 64 Settings a sedes a ee Reap Ota b et t die vl ur dades 7 65 Controls Settings Menu eei edu eee eds 7 65 Other SSA Check Mens gu shes bte ri Deben 7 65 Any Data Check 2 2 7 65 RTA Check Menu a Asa ete 7 66 Intervals Check Men snnt boe ope E 7 67 Time History Check Menu eee en e de ee enn 7 68 Run Log Check Men eere tat aao edited eed 7 69 Li Cenules Check Menus 7 70 Other Logging LOG Check 7 73 Any Data Check Menu nennen enne 7 73 Current SLM Overall SLM Check Menu sese 7 73 Exposure Check Ment ise
248. OG Daily Ln Table in hexadecimal hhhhhh hhhhhh hhhhhh ih A 64 824 Reference Manual 9 29 09 D 20 LOG Intv Ln 1 Percent nn D21 LOG Intv Ln 1 Level dB nnn n D22 LOG Intv Ln 2 Percent nn D23 LOG Intv Ln 2 Level dB nnn n D24 LOG Intv Ln 3 Percent nn D25 LOG Intv Ln 3Level dB nnn n D26 LOG Intv Ln 4 Percent nn D27 LOG Intv Ln 4 Level dB nnn n D28 LOG Intv Ln 5 Percent nn D29 LOG Intv Ln 5 Level dB nnn n D30 LOG Intv Ln 6 Percent nn D31 LOG Intv Ln 6 Level dB nnn n D32 h LOG Intv Ln 1 Percent nn D33 h LOG Hourly EXCD Leq nnn n dB h hour 0 23 D 101 LOG Hourly BkGd Leq h hour 0 nnn n dB 23 D102 LOG Daily HNLs 5 0 23 6 0 23 Macro Run Log Variables SSA ISM LOG TAL Brackets in the syntax indicate optional characters and operands Syntax Response 9 29 09 A 65 L og var_nolog var Example L1 Run Stop number L1 Run Stop Number nnnnn L2 Run Stop Type RUN STOP CONT PAUSE MARK L3 Cause TIMER KEY A D n HALT INTV BATT L4 Day Date and Time ddd ddmmmyyyy hh mm ss L 101 Run Log Macro Variables L1 L5 Macro Calibration History Variables LOG Brackets in the syntax indicate optional characters Syntax Response C alibration var no cal var Example C1 114 0 ch
249. OG and one ISM setup ID These three setup ID are created from the Tools gt Memory gt Create EEPROM Backup menu item You may want to perform a User Reset If the settings stored in the memory of the 824 have become corrupted A User Reset is performed whenever the firmware is upgraded It advisable to make archive copies of all setup IDs using 824 Utility software regularly 824 Reference Manual 9 29 09 See Keys Control Ke lc 3 2 Numerics 824 GOMPONEMUS NE 1 10 Features C 1 7 Opt onal equipment tte eee Te EPOR eO DAE ege dem Paes 1 16 System C 1 13 Terminal assembly EE E 1 20 824 Utility Adding Notes to Download File 10 21 Additional Features terret ete Ae ea 10 32 Changing download file name nnn 10 20 Gonnect ng to a PG o E EEUU chew to Saco ee RE Ip tests 10 2 Creating a New Setup edges teretes eee ier eurer i a a 10 14 Deleting Setup RR teneret UI cite de 10 16 Downloading Measurement Data sse 10 17 Downloading selected measurements sse 10 22 export datas ote reote a e requi tt eae eme ende 10 32 File Extensions sss ap RI iet da o a Re s 10 24 5 e enero
250. Previous View on page 1 5 This introductory chapter covers the following topics Formatting Conventions Provides an explanation of the fonts and other formatting conventions used in this manual Features Gives an overview of the System 824 keypad functions and measurement capabilities Getting Started Provides instructions for unpacking inspecting and initially assembling the System 824 This manual uses the following format conventions In step by step directions the process what you do is shown in the right column and the rationale why you do it with other cautions and comments are shown in the left column Keys to press on the LxT are shown with the icon representing the appropriate key For example Press the b key Items that appear in various on screen menus such as settings are shown in bold and italicized style For example Detector Slow 824 Reference Manual 9 29 09 Features Hardware Features 9 29 09 The Larson Davis System 824 has the following features Large backlit bitmapped graphic display Soft rubber backlit keys Pop up menus with scroll bars Pick and choose setup just click and run File management system stores multiple measurements Multiple Instruments SSA Sound Spectrum Analyzer combining a sound level meter and real time spectrum analyzer optional LOG Logging SLM optional ISM Integrating SLM standard RTA Add
251. Printing a Report 8 1 Printing Reports Depending on whether you have selected an SSA ISM LOG or RTA instrument from the Setup menu you will have a different Print menu available The screen shown is for the SSA instrument The TAL and FFT instruments do not generate any reports Step 3 Step 1 Turn on your printer and the System 824 Press the ili Data key and use the Recall Files menu to recall the measurement record that you want to print You may not need to recall a file if you want to print something in memory that has not been stored Step 2 appears Pr int Press the Print key The following screen The Print menu provides different options depending on instrument type The following table shows the menu options for the SSA ISM LOG and RTA Print menus Menu Item Options Description Available To Status shows the status of the printing job SSA ISM LOG RTA Settings Printer Type SSA ISM LOG Printer Baud RTA Flow Control SPL Report prints an SPL report ISM Summary prints a summary report SSA LOG RTA Tailored prints the tailored report SSA LOG 8 2 824 Reference Manual 9 29 09 Recall Format Summary Tailored short All long None enabled SSA LOG Customize allows you to select the print options for an instrument ID and customize your reports see the section on Printing a Custom Report SSA
252. RE dE e tt D 9 Frequency band pass eee HERR eens baa eta D 10 BIOSSATY wos seve eaa ttd RI eoi sima etse t fee a e e e pte D 9 Hz tad S663 einen RIRSWU ED eC D 10 Frequency Response Average Corrections ee te p e e A RE F 2 Frequency Response Specifications sse nennen ener enne eren C 24 Erequ ncy Spectrum veces oec edet IRURE HERR EEUU Ge dina EE ER Ee DERE TIR D 22 G Getting Started chico Ae ed tl ets 1 14 Graph Menus 7 64 H Heater Comtrol PEE 7 16 High Range calibration cente tee oria inne ee ptos 4 4 linearity range a irse e de etie IR TE CR EN RE OUS ee EGER 2 4 Histogram cer RITE EE eee vo ae e oe re i vete e A 44 Start Level boob aeta Me G 4 History Advanced Time History dn e etai dito et aie tie at ERES 7 35 Daily History cet e e ERR REEF ON e ea 64 iv viii Index Model 831 Technical Reference Manual Enable eR e tees 7 32 Exceedance Histoty son eee rer EATUR He 57 History Data Variables gt A 57 Interval History eto et te HUI ER Dd 59 Marker Text eno U Da RR pt 7 35 Other Level
253. REG qu E e 3 12 Keypad sisse uius e nouus du qiiia mats 3 1 L Leq DSP instrurments vs analog ir e Ree Re Ri Eb AS ER Re G 5 BOSS ANY zo T hs EQ ETE RE Ode ER D 8 5 eds G 5 IMPR D 12 Dept of Defense iranan a e b eo IRI edi t AT RA ER RN D 8 Linear Range A Weight Limits i RA TER REIR IR EE OR ERE EDU F 5 Links 4m etie RA RR edi ate d Rd enit aU ees 1 5 Ln Spectral ERR IRR SER RR eh RR 5 21 L n Cen les tort 5 19 Check niina 7 74 uc 5 35 Ln Settings pe dents ees iet qt ess 7 22 Enable csi tek ei BA e rte o pe ie o e 7 21 Spectral Lis 7 22 LOG ih eae 7 25 7 30 7 36 PEE 2 4 LOG Meastiring Ranges ERE t EINE A oes 6 9 LQG Sette M EK 7 52 ER 7 42 Logic Input Set Ipse tete eh rdiet ie sete 7 12 Logic Output 7 13 Logic Output 2 Selina dti etti evt ie tue ice ah 7 16 Logic Output 2 Time I ERE OR T A RE ORA RO CARTES 7 16 Logic Output Time ertet redis Av EU Rd td d Pd eiie tee 7 15 M Manual Bookmarks nenne tea
254. RTA Max graphical views The fol lowing menu appears SLH RTA ols Step 2 Highlight Tabular using the W arrow keys then press the Y check key A tabular dis play like the following screen appears SLA RTA Live A e3aBHz 12588Hz To 66 saaBHz 158BB8Hz 2 dd 61 8 18888Hz 61 306 a4 Z Step 3 To return to the graphical view press the Y check key and the following menu appears 824 Reference Manual 9 29 09 Time History Displays SLAY RTA Spectrund Settings gt Bandwidth 31 Select Spectrum to view the graph again The following are examples of the graphical displays for the SLM Time History and RTA Time History Views SSA Time Histor RECORD 20 OF BA 47 017 MWA 5 ed 40 SLM R TA l Live SETTE IH Ley ian 34 9 m SSA Intervals NOTE SSA Intervals are only available when the LOG option is installed See the section Intervals on page 5 44 for a description of the Interval a through Interval d displays Only Min or Max can be displayed 9 29 09 The up and down arrow keys change the record you are viewing The D or 4 arrow keys change the position of the cursor The Interval History shows a record of various sound pressure data and spectral data including spectral LNs gathered in time segments over the run time of the 824 An example w
255. Rd 13 14 Linearity RTA Display ennemi enne 13 10 Microphone Sensitivity Calibration sese enne enne 13 4 IMO ES ettet E tte M e 13 4 Pulse EM Display xac eee E ie t RITU PR vet reete 13 21 P lse EM Submenu 2 45 etn redet ee detener e pt ete e ved eet cogn 13 5 Selecung Modei EE Ree eem 13 3 SE M RTA Submienu hat e e ti b 13 5 SEMRTA Live Display 13 6 THD Display ei pp eie ters 13 19 bj A E M 13 5 iv ii Index Model 831 Technical Reference Manual Audiometer Testihg een eie ie RR GERE RE RE EE Reed 13 1 Autostore Re Re e eR ERE OR RR COR ee e dens 11 29 ByTime Spectral History i ae o ea ee ee i Gato eere Utd 11 29 By Time pe ctr win ce nere reet o HR GR RE pes 11 29 SCG dtl tetemamn One eaten dtm 11 26 ud uten ree ide memo ENE ettet de ds D ertet tU S RR ee des 11 25 B Back Erase ias RU SERT Sp Bt ias niet A aoe a e ert 3 10 Back erase function eu eet terere e ede Ce 2 8 Backlight Times oed REPARARE t ee eee 3 5 Backup EEPROM nier eio ein tected e eta e re oce e dere Spore edo ee Pes 3 19 Battery Ours 1 20 E
256. TALL 824 Utility Software The 824 utility software will automatically begin the installation process The installer program will prompt you through the installation A message will appear indicating that the software was suc cessfully installed Starting the 824 Utility Software BE X N To start the 824 Utility software in Windows press START and then select the Programs Larson Davis 824Util menu item KE Larson Davis US Microsoft Reference 53 Microsoft Visual 5 0 53 Netscape Communicator America Online 4 0 53 Novell 53 Online Services Netscape SmartUpdate Paint Shop Pro New Office Document Lj Pathway Client NFS 6 0 pcANYWHERE32 Open Office Document a PowerPanel H Real Documents Sound Blaster 16 Y ov ov v v v v v v vy vy B v c Connecting to Your Computer 10 2 To connect the 824 to a computer use the CBL006 cable included with your System 824 The round 8 pin connector 824 Reference Manual 9 29 09 plugs into the Serial port of the 824 and the 9 pin connector plugs into a serial port on your computer You do not need to be connected to the 824 in order to translate files which have already been downloaded NOTE The 824 will power on when it senses anything on the serial connector You may notice the 824 powering on automatically before you press the power button Before any functions can be performed on the 824 you must conne
257. TOTAL Run Time in days unti out of memory see TOOLS Memory Enter total memory shown divide line 38 by line 37 Table E 7 LOG Memory Usage Worksheet 824 Reference Manual 9 29 09 824 SSA Memory Usage Interval Records Intv History Enabled Basic Interval Record includes Leg Spectrum Intv M ax or Mins 66 Spectral Ln Interval 396 Intv Ln Table Win ahve Table E 8 SSA Memory Usage Interval Records 9 29 09 7 Time History Records Time History Enabled E 8 Bytes per record Resolution 0 1dB Resolution 1 Basic Leq selected by the Weighting setting 2 1 Leq A option 2 1 Leq C option 2 1 Leq 2 1 Peak A option 2 1 Peak C option 2 1 Peek Hat 2 1 Lrex Sow option 2 1 Lmx Sow C option 2 1 Lmex Sow option 2 1 Fast option 2 1 Lmx Fast option 2 1 Fas 2 1 Lrex option 2 1 Lex option 2 1 Lmex Hat 2 1 Imn Sow A option 2 1 Imn Sow option 2 1 Lmin Sow Ha aption 2 1 Lmin Fat option 2 1 Lmin Fast option 2 1 Fast 2 1 Lmn Inp option 2 1 Lmn 2 1 Inp Flat 2 1 lve SPL Sow A option 2 1 lve SL Sow option 2 1 lve SL Sow qin 2 1 SL Fat A option 2 1 lve SL Fat C ption 2 1 SPL Fest 2 1 lve SL Im A option 2 1 SL
258. Tests The FM modulation test code computes the minimum and maximum periods of the input waveform The minimum and maximum frequencies are the inverse of the average of the last 8 periods The carrier frequency is an exponential aver age of all waveform periods Signal will be flagged as stable if the carrier period varies less than 8 microseconds for 1 second Carrier frequency 20 Hz lt f lt 16000 Hz Modulating frequency fm 3 Hz lt fm lt 100 Hz Carrier to modulating frequency ratio fo gt f m 5 Signal amplitude Overload 35dB Overload SLM RTA The 1 3 octave filters used in the audiometric calibration firmware are the same filters as are used in the SSA firm ware and meet the same specifications page D 8 400 Line FFT Averaging Count Window Rectangular or Hanning Linearity range gt 85 dB with Hanning window 20 kHz bandwidth and PRM902 Dynamic range 2100 dB Flat SPL linearity range gt 75 Highpass frequency vs filter bandwdth for 824 FFT Bandwidth Hz Bin 0 2 dB 20 000 50 00 9 5 10 000 25 00 6 5 5 000 12 50 5 5 2 000 5 00 0 85 1 000 2 50 0 85 500 1 25 0 85 200 0 50 0 85 824 Reference Manual 9 29 09 9 29 09 Typical response of AUD A weight and C weight high pass filters Frequency Weightings
259. The Linearity FFT check menu contains the following items Set Reference Set the reference level to the current level i e zero the display Reference Lvl Reference level setting that may be entered manually Gain Changes the gain setting of the instrument Generally use OdB gain for levels at 70dB SPL and above and 30dB gain for levels less than 70dB SPL The Auto Gain Control AGC function of the linearity displays step between 0 and 30 dB gain if the gain setting is something other than 0 or 30 the function is inhibited Weighting This setting selects either A C or Flat frequency weighting as a filter prior to FFT filtering Trigger Level The Trigger Level setting defines the level below which the automatic frequency lock becomes active Note The Lineanty FFT display when using A or C weighting should not be used to measure frequency response and is not good to use for absolute amplitude measurement Always zero the display at your reference point and use the relative level to see changes in amplitude relative to that reference Note also that the FFT s A and C weighting filters AUD Optional 13 17 Flatness FFT Display The Flatness FFT display can also be accessed from the View Menu as described in View Menu on page 13 5 13 18 may have up to 0 2dB variation compared to the FFT Flat weighting due to component variations and tolerance The Flatness FFT display shown below 1s can b
260. The numbers in the table represent SPL levels with a typical 377B41 microphone which has 44 1 mV Pa sensitivity C 14 NF is electrical noise floor AUD Mode Specifications AC DC output For AUD AC and DC outputs are undefined Pulse mode The pulse test output is computed from a Discrete Hilbert Transform which is sampled every 7 millisecond The Discrete Hilbert Transform produces a mathematically correct sample of the input waveform envelope Time resolution 0 5 ms to 1 0 seconds in 0 5 ms increments Time accuracy 1 0 ms Hilbert transform lt 0 1 dB magnitude error Dynamic range gt 80 dB Hilbert transform 2000 Hz Sample rate 824 Reference Manual 9 29 09 9 29 09 On level computation After the ON state has been detected the ON level is computed as the average of 32 samples Overshoot computation Overshoot is calculated as the maximum sample level minus the averaged ON level Measurement conditions Conditions that must be met to produce output ON OFF modulation must be greater than 20 dB 90 The ON state must be stable within 0 5dB for at least 20 ms Pulse transition from high to low must occur within 2 sec onds of the transition from low to high for the fall time to be calculated If this time is greater than 2 seconds the 824 will revert to looking for the pulse rise time FM Modulation
261. The status indicator will show one of the six possible events that occurred at the point of time referenced by the time cursor Run Indicates that a measurement started at this time Stop Indicates that measurement stopped at this time Pause Indicates that the measurement paused at this time Cont Indicates that the measurement continued at this time Reset Indicates that the measurement was reset at this time Mark Indicates that a marker was set at this point in time 824 Reference Manual 9 29 09 Run Log See page 6 41 for a description of the Run Log display Ln Centiles To access the Ln displays press the View key use the W key to cursor down and highlight Ln Centiles Press the right D arrow key to view the Ln displays The following menu will appear Spectral Lns are enabled by the Spectral Ln setting These data and displays are only available when set to Overall See the section LOG and SSA Ln Settings on page 7 20 Highlight Broadband and press the check Y key to view the SSA Ln a display Display label 55n L n a _ 1 Lg 23 96 6 3 7 Percentile values amp levels 22 2 50 0 T4 Z 69 3 66 7 40 0 eo B 136 7 9 29 09 System 824 Views 5 19 The following is a brief description of each of the components of this display Display label The Display label ide
262. Yes 440 19 TOTAL Daily Bytes Day Sum lines 14to 17 copy to line 32 Time History Memory Calculation i Other Level Resolution Bytes per record Used 1 0dB None 0 1dB None 1 1 0dB Pk II Pk I Lmax 0 1dB L max 1 0dB Advc 1 plus number of Y Calculate enabled levels 0 1dB Advc 2 plus 2 times each Y Calculate enabled levels 1 0dB Advc Wind Tach Yes 0 1dB Advc Wind Tach Yes TOTAL bytes Hist Record Select the appropriate number of bytes from lines 19to 26above Hist Records Day 24 hours divided by Hist Period in hours Enter Number Calculated i e 24 60 sec 3600 sec per 1440 TOTAL Hist Bytes Day Multiply lines 27 amp 28 copy to line 33 Memory Use per Day Calculation Exceedance History bytes day from line 6 Interval History bytes day from line 13 Daily History bytes day from line 18 Time History bytes day from line 29 Run Log bytes day n number of Run Log records day 20 n x 20 bytes record Calibration Log bytes day n number of Cal Log records day x17 n x 17 bytes record Setup RAM Registers bytes used n number of registers stored 506 n x 506 bytes record TOTAL bytes used day Sum lines 30 to 36 824 s Memory Size 2 000 000
263. a If you press the RESET key while the instrument is running the instru ment will reset its data buffer for the current measurement and set the elapsed time for the current measurement to zero without affecting the data in the overall measurement If you press the RESET key while the instrument is stopped a menu will appear that will give you the choice of resetting the current data or the overall data together with the appropriate elapsed time counters When editing system or instrument settings containing a string of numbers or characters the RESET key also be used to clear the characters from the current position of the cursor to the end of the string Front Panel Keys Functions and Menus 3 9 10 Pause Key Pause Pause Back Erase NOTE Moving the cursor bar left is like moving back in time 3 10 The 10 PAUSE key has 3 basic functions in the ISM and SSA instruments To Pause a measurement to avoid unwanted noise from entering into the measurement data To erase unwanted data from the measurement and to preview the data coming into the instrument without registering the data The first function of the Pause key will cause the instrument to not accept any incoming data Unlike pressing the stop key pressing the pause key will not start a new measure ment but rather will simply pause the existing measurement for a moment After the desired pause period press the pause key 10 again to resume the m
264. a Folder Palatino Fonts 21 165 08Sep2tr simdl a 1 Sys Settings 8 1 Cal Settings 8 1 RTA Settings 1 nts D8Sep21s simdl H For Help press F1 SCRL 2 824 Reference Manual 9 29 09 Printing a Translated File To print the translated data select the file that you wish to print from the translate window Display the file as described earlier Select Print from the File menu C Program FilesNLarson D avis amp 824 Utility C 824 2 0271 2 101 1 610 Enter Company Name Enter Address Line 1 Enter Address Line 2 slm amp rta ssa SLM amp Real Time Analyzer Ctrl P not set 114 00 dB Auto Off Auto Off Time 12 mit On Backlight Off Time 30 se 64 9 29 09 Using the 824 Utility Software 10 29 10 30 SLM amp RTA Summary File Translated The default Windows printer dialog box will be displayed The report will be printed in a text format similar to that shown below 10 Jul 2000 16 59 33 C Program Files Larson Davis 824 UtilityM28Junl5s slmdl Model Serial Number 824 A0138 Firmware Software Revs 3128 7 25610 Name Descrl Descr2 Enter Company Name Enter Address Line 1 Enter Address Line 2 Setup Setup Descr slm amp rta ssa SLM amp Real Time Analyzer Location Notel Note2 Overall Measurement Start Time Ln Start Level 28 Jun 2000 15 45 51 15 11 00 0 0 dBA 150 00 0 0 dBA
265. a True RMS detector circuit that has an exponential time constant generating a voltage proportional to SPL with the Slow or Fast response with an ADC Analog to Digital Converter That sample rate is many times per second to ensure accurate Leq readings If an Leq time history is taken in this type of instrument and the storage rate is fast enough you will see that the Leq will not decay any faster than the detector rate of the SPL it is sampling New DSP based sound level meters do not have the analog detector but rather detect the SPL and Leq digitally by sampling at a rate that 1s double the highest desired frequency Nyquist and then processing the waveform The System 824 uses a sample rate of 51 200 samples per Question 6 Answer Question 7 Answer G 6 second The Leq detector and the SPL detectors can be totally isolated without any additional circuitry the cost to do this with analog circuitry would be very prohibitive So what 1s an Leq It is the energy average of a signal over a period of time Now with separate digital detectors the Leq does not have to exhibit the decay of the SPL exponential detector but can be true to its definition That means that 1f an Leq time history is taken in this type of instrument you will not see any SPL decay effects Is this good or bad It is different more than good or bad but there are benefits from that difference Good Many scientists feel that this is good because L
266. a eei eee hie s ISM and LOG Modes Main Characteristics sss Max Input Voltage esee Measurement Range ISM LOG Measurement Range SSA Peak Detector cete Peak Range ISM LOG Physical Characteristics Power Supply etit esten Resolution 5 eoe RTA nni ep SSA Mode ceret i dri Spectral Lins te eer tend SGA etie dee eee edere Measuring Ranges sse Settings Jason e RR ES Stabilization Time Environmental Changes sss Standby TIME essnee neo Re Re Start Level ER ese Starting Measurements 2 Statistical Views sess embodied e Check Men Status E eres Stop Datei me mp eatem External trigger eese PUN CHO Mies tte e e Rie rs TMe 1V XX Index Model 831 Technical Reference Manual Stopping Mea suremients rH E EROR D ERE RETE E RE RE RE ipte renes 2 8 Storing T 2 13 System Diagram s stato oerte ies Vari a ente UR I 1 15 System Settings cune eee e retener ce tet dee e eias 10 9 T
267. al Data RTA Live RTA Leq RTA Max and RTA Min a i B i al I E Tm SLMHTRTH Live SLA R TA W SLM FRTH ED 58 HHz 00 18 75 n In the above views the cursor position the vertical bar in the graph corresponds to the level and frequency values shown the left side of the display The cursor or frequency bar position can be changed by pressing the arrow keys As the arrow keys are pressed the vertical bar moves 9 29 09 System 824 Views 5 11 Tabular SSA Views The Tabular display can also be accessed from the main View menu by highlighting the desired RTA view pressing the D arrow key and then selecting Tabular from the submenu that appears While in the main tabular view the and W arrows keys cycle you through the different spectra s i e RTA Live RTA Max and RTA Leg tabular displays The D and 4 arrow keys move you through a series of tabular displays showing the current spectra 5 dB readings at each center frequency 5 12 to the appropriate position and the frequency readout changes accordingly In addition to a graphical view a tabular display 18 also available for the RTA Live RTA Leq or RTA Max modes which shows a tabular listing of the dB readings at specified frequency levels in each of these spectra To access the tabular displays do the following Step 1 Press the Y Check key while in the RTA Live RTA Leq or
268. and 260 ms Off Time F J time in milliseconds between successive 5 dB points of the envelope of the pulsed signal during which the signal is absent nominally between 190 and 260 ms Plateau or Pulse Width C E duration in milliseconds of the plateau during which the signal is within 1 dB of its nominal value e Overshoot L the level in dB that the signal rises above the normal ON level SPL on Instant of switch operation ON Figure 13 1 Pulse Parameters 9 29 09 AUD Optional 13 23 Pulse FM b Display Pulse FM Check Menu 13 24 Pulse FHM b Carrier ax Hin Mod Rate SPL 3 4dBF This screen displays required values for the calibration of the frequency modulated tone capabilities of an audiometer Present the frequency modulated tone at an appropriate level and press the RUN STOP key When the stable message is displayed as shown below press RUN STOP again and read the values from the screen Pulse FM b Stable Carrier 745 627 Hz Hod Rate 13 33 Hz SPL 38 8dBF The following values are displayed all in units of Hz Carrier frequency Maximum frequency Minimum frequency Modulation rate While in either the Pulse FM a screen or Pulse FM b screen the check menu can be accessed by pressing the check key This menu contains the following items 824 Reference Manual 9 29 09 F
269. and Interval records as selected by option settings Using ID Setting Files 7 25 The Wind Tach feature requires the optional firmware 824 WND If it is Wind Tach B not installed attempting a setup will Hat Available display the message shown to the pele This option be purchased Please contact Larson Davis Phone 861 373 0177 Setup of Wind Tach Function With either the LOG or SSA instrument active press the SETUP key to access the Edit Setup Menu Using the arrow keys highlight the Advanced item and select it using the D arrow key or the Y Check key iiti Using the and W arrow keys highlight the Wind Tach item and select it using the arrow key or the Y Check key to display the Wind Tach menu ae Mind Scal 592 l Hind Units CHPH gt Direction Unit Menu Items Available Settings Options Wind Scale nnn nnn Wind Units 7 26 824 Reference Manual 9 29 09 Wind Scale 9 29 09 Menu Items Available Settings Options Direction Unit Compass Degrees Percent Volts Number Wind Tach No Yes Windy Threshold nnn n or nnnnn Wind Level nnn n or nnnnn Windy Hysteresis nnn n or nnnnn Windy Pause No Enable Yes Pulse Trigger 0 0 Voltage 2 5 Pulse Trigger Int Source Ext Wind Scale is a scale factor which provides the wind speed tach when multiplied by the frequenc
270. and also for the daily period data for the LOG instrument NOTE Storing the complete histogram for each interval and daily record greatly reduces the number of events that can be stored 9 29 09 Using the 824 Utility Software 10 33 RT60 Select Options The 824 Utility software can calculate an RT60 for each 1 3 octave frequency from the autostore ByTime data taken by the RTA instrument The software gives you the flexibility to set the options for the calculation and display of the RT60 values You must first take an autostore ByTime measurement Download the measurement and go to the Translate view and select an RT60 report 824 Utility i a XJ File View Setups Data Help aaa EN efe 05Jull6r O05 slmdl 05Jul 6r 006 slmdl m i 05Jul18s 002 slmdl BE 28Juni5r slmdl 8 1 Sys Settings 1 Cal Settings E 1 RTA Settings E 1 RTA Events E 1 RT60 Analyses 8 1 Summary 9 8 28Jun15s slmal E B 28Juni7i slmdl RT60 REPORT File Translated C Program Files Larson Davis 824 Utility 28Jun1 5r simadl Model Serial Number 824 A0138 Firm Software Revs 3 128 2 610 Name Enter Company Name Descr Enter Address Line 1 Enter Address Line 2 rt amp 0 b rta RT 60 Real Time Analyzer s DNA 1 averaged events Duration 3 010 dB Down 10 dB Microsoft Money Freq Hz RTB0 sec Freq Hz RT60 sec Microsoft NetShow 125 0 52
271. and on the screen as shown below Linear Units sss bok 9 29 09 FFT Optional 12 15 Linear Units Linear Units is simply 4 alphanumeric characters defining the units name as it will appear on the screen Linear Scale Linear Scale is the value of Linear Scale calculated as shown in the preceding sections Input the desired values for both Linear Units and Linear Scale by highlighting the item pressing the Check key entering the values and pressing the Check key again to close the menu Below is an example of the FFT live display with linear units Standard dB level at cursor i40 Linear amplitude Jw 20 1 7 Frequency shown by cursor M 6754 oy Fia Linear Units _ gt q 0 In this case it shows 20 12 milli g acceleration 12 16 The following explains each of the display s components Standard dB level at cursor This is the dB display which appears whether or not the linear amplitude is displayed Read out at cursor This is the linear units level at the cursor NOTE The units level is displayed in engineering exponential notation Linear Units This is the unit entered by the user in the menu for Linear Units In this particular case we have entered for acceleration Frequency shown by cursor This is the frequency as shown by t
272. andwidth Allows you to reduce the frequency bandwidth setting divided by the bandwidth from 20kHz to 200Hz This setting provides lines setting the following options 200Hz 500Hz 1kHz 2kHz 5kHz 10kHz 20kHz Snapshot Once you have stored an FFT snapshot by accessing Store Snapshot from the FFT check menu you can view the snapshot data by pressing the View e key The following menu appears FET SnapshotOis Highlight Snapshot and press the Check Y key to access the snapshot data Date and time FR 19 517 19 27 02 Snapshot number _ i a total number 67 7 of snapshots Use the up and down arrow keys to scroll through each record Use the check menu to control the HORIZONTAL SCALE The date and time records when the snapshot was taken 9 29 09 FFT Optional 12 11 Snapshot Check Menu To access the snapshot check menu press the Check Y key while viewing the snapshot data The following menu appears The check menu offers the following options Locate Locate Snapshot record First The first Snapshot record Last The last Snapshot record Find Finds the specified Snapshot record Graph Adjusts the graph scale and offset See 824 Reference Manual Graph Level Allows numerical entry of graph level in dB Graph Scale Allows numerical entry of graph scale Zoom in Allows you to see FFT sp
273. are The 824 Utility software is a powerful tool for use with the System 824 from Larson Davis This software will allow you to control setup download and translate your 824 measurement data quickly and easily The 824 Utility program has three sections that perform the functions on the 824 The setup section provides support for creating editing storing and retrieving setups from the 824 and from files The download section provides a means by which to retrieve the measurement data from the 824 The translate section provides support for translating the downloaded measurement data and displaying or print ing it in a text format or exporting the measurement data to a spreadsheet program In this chapter we will discuss installing the software get ting the software started on your computer connecting the 824 to the serial port of your computer explain the Main Screen Toolbar functions and then go onto discuss each of the three functions of the software in greater depth To install the 824 Utility software package place the disk CD into your CD ROM drive From Windows 95 press 9 29 09 Using the 824 Utility Software 10 1 START and then select the RUN menu item A prompt will appear to enter the program name Enter E 824auto exe A new screen will appear with several menu items to choose from Select Install Software from the menu items Another screen will appear with several more choices Select INS
274. ast An exponential average with a 1 8 second time constant Using ID Setting Files 7 5 There are certain features such as event counting that function only with one selection of frequency weighting and selection of detector both user selected These same weighting detector selections also determine the metrics used for features such Ly Intervals Exceedances etc Weighting Setting SSA LOG ISM Gain Setting SSA The Gain setting is only available in the SSA instrument The 10 and 20 dB gain settings are not available for electret or direct transducer types see Transducer 7 6 Impl An impulse detector which has a very fast rise time a 35 mS time constant but a very slow decay time Weighting selects the desired frequency weighting for the RMS and secondary peak detectors The Weighting setting provides the following three options A The instrument uses an A weighted input filter C The instrument uses a C weighted input filter FLT The instrument uses Flat weighting see specifications for passband frequency in Appendix C Gain The gain setting sets the measuring range of the instrument in 10 dB steps by adjusting the amplification of the microphone s signal The gain is set from the SSA Setup Menu highlighting and selecting SLM then Gain to obtain the following Gain Menu In the display the lowest and highest levels that can be measured accurately are ind
275. ator Hourly Leq graph The Hourly Leq display is shown below Date Tue uon 1999 m Record Number 4 Display label Hourly be Hourly Reading 9 Exceedance Exi eit staged es Background Leq 59 5 yp Hour indicator Hour 18 Eie Ja Hourly Leq graph The following explains each of the display s components Display label This shows the current display for example Hourly Leq Date Date of the record Record Number The record number indicates the order of the displayed Daily record in relation to the other records Hourly Leq Reading This is the hourly Leq as shown by the cursor Exceedance Leq This shows the average level of all of the exceedance events 824 Reference Manual 9 29 09 Metrics The and W arrow keys can be used to cycle between the Metrics PassBy and Wind Tach views Metrics a Display 9 29 09 Background Leq The background Leq is the hourly Leq minus the exceedance Leq Hour indicator The hour indicator shows which hour of the day is being displayed A following the Hour indicator means that the measurement was not for a full hour Hourly Leq graph This graph shows the Leq value for each hour Use the D and 4 arrow keys to move the cursor to view the Leq background Leq and exceedance Leq for each hour The Metrics View has tw
276. ator Overload detector SL LIS SPL 510120 T DE 100 H an Indicated weight under range near noise floor indicator F ly Le 33 THER H2 35 25 The following table describes the icons that may appear Icon Description Animated Running Figure The instrument is running and acquiring data Solid Box The instrument is stopped data available Open Box The instrument is stopped and reset Open Box with small solid box Viewing a recalled file Solid Box with open box in middle OverAIl or Current data are available but not both 5 2 824 Reference Manual 9 29 09 NOTE To set the noise floor level go to the Tools menu highlight Calibration Scroll down to Noise Floor and press the key Enter the noise floor using the value provided by the microphone manufacturer S specifications 9 29 09 Double Bar The instrument 15 paused Play Symbol The instrument is ready to run as soon as stabilization completes Arrow Under Range Near Noise Floor Indicator The instrument is under range when the arrow 1s longer The instrument is near its noise floor when the arrow is shorter The system indicator in the upper right corner of the display will indicate when any A C or Flat instantaneous Leq inputs are under range or near the noise floor The indicated
277. aves 824 s power on M 11 Lock 824 and Power Off cease sending further commands M 12 Disconnect Modem terminate connection and hang up M 13 Extend Modem Connect Time out can be set up to 255 seconds and allows time for modem diagnostics 1000 Test RAM non destructive walking bit test data left intact 1001 Test RAM destructive pattern fill amp test setup recalled from M2222 Store current setup to EEPROM Response Stored takes 20 seconds Enable I O Error Check Scheme documentation available on request 5205 0 or 2 to 3 CR in a row will disable Error Checking Read Commands Reads out data variables The various read commands are detailed in the following tables The tables list the variable number the variable name a description data format and instrument types for which it is valid Some of the Read commands also utilize second operand Syntax Instru Description Response ment Type RI Device manf and model 30 characters String A 10 824 Reference Manual 9 29 09 R11 Option feature identification 8 characters F3 E0 M3 Used to determine optional features of the system The returned string will show the availability of a filter card the ENV firmware option and the memory options The filter has 3 options None FO 1 1 octave filters F1 and 1 1 plus 1 3 octave filters F3
278. ay The Time History display consists of seven major components Display Label Current Record Level at cursor Time at cursor Current sample Total number of samples Total number of Excd records Graph of Exceedance Time History The Excd Time History display is shown below 824 Reference Manual 9 29 09 Total number of Display label B Excd records Current record dE iun Level at cursor 9 65 A Bt Time at cursor 15 Pli un 25r 33 Graph of Excd time history Current sample Total number of samples 9 29 09 The following explains each of the display s components Display Label This shows the current display for example Excd TH Current Record The Excd TH display shows each exceedance record in the order that it occurred This number shows that you are viewing the time history corresponding to this particular exceedance record Use and keys to move forward or backwards respectively through the sequence of Exceedance History records Alternately you can press the key highlight Locate and press the key again This will open a window permitting you to jump to the first or last Exceedance or to a selected exceedance record Level at Cursor Shows the level in dB at the point in time indicated by the cursor Use the P and keys to position the cu
279. bar 10 14 From the displayed dialog box select the type of new setup Select New Setup Type x S5A Simple Sound Analyzer SM Integrating Sound Level Meter Cancel C LOG Logging Sound Level Meter C TAL TALarm C RTA Real Time Analyzer Press the OK button and you will now see the new setup in the Setup List box 824 Utility olx File View Setups Data Help Eea SLM Time History Intervals Timer Advanced ee ystem SLM amp ATA Sound Level Meter Real Time Analyzer Settings SLM SSA x SLM RT default ssa tos Logging tos demo ROOMS RTBD Title 1 amp Real Time Analyzer TA LARM FFT SLM Detector Slow RTA Detector z carpente Freq Weighting Bandwidth 1 3 he Peak 1 Weighting Fiat 7 RTA Weighting Flat 7 0 Y Output Control aca AC 2 E For Help press F1 2 824 Reference Manual 9 29 09 If a message window occurs after pressing the OK button like that shown below A The file that is used to create a new 824 setup is missing For directions on creating a new default setup file see help file or documentation you will have to create a default setup file by following this procedure Select the permanent setup for the desired instrument type Under the File menu select
280. be set accordingly so that the synchronization works properly When you start a measurement the initial storage interval will last for only a fraction of the determined synchronization until the start of the next time segment at which time a new synchronized storage interval will begin This setting provides the following two options No Disables interval synchronization Yes Enables interval synchronization Intv Save Ln s either enables or disables the automatic storage of the six Ly percentile levels in the interval record This setting provides the following two options No The six Ly levels are not stored with the interval record Yes The six Ly levels are stored with the intervalre cord NOTE If Intervals are enabled and Interval Ln s are enabled and Ln s are not enabled then Ln s are turned on and the warning Setting Conflict 1s displayed Use the Intv Auto Stop setting to enable or disable the auto stop feature When enabled this feature causes the instrument to automatically stop the measurement at the end of each storage interval This allows you to precisely time a series of manual measurements To start a new measurement after an automatic stop just press the Run Stop key This setting provides the following two options No Disables the automatic stop feature Yes Enables the automatic stop feature 824 Reference Manual 9 29 09 Intv Threshold LOG SSA Intv Exchange LOG SSA
281. bient environment and switching the power on the elapsed time until the meter may be used to measure the sound level is as follows e lt 10 seconds using a prepolarized electret microphone minute using a traditional condenser microphone requiring a polarization voltage When performing an integrating measurement the data 1s available during and immediately following measurement time interval The averaging time is determined by how long the measurement is allowed to run as indicated by the digital display in the lower left of the screen For low level measurements where the measured level may be affected by the system noise floor it is recommended that an averaging time of at least 30 seconds be used For timed measurements the value of the averaging time can be preset and the instrument configured to stop automatically after that time as described in the section Measuring for a Preset Integration Time on page 9 16 824 Reference Manual 9 29 09 Linearity Range When making a measurement the upper and lower linearity range limits of the instrument for the setting presently in effect are indicated by the dark regions with light numbers as indicated below Upper Limit of Linearity 58 2 Lower Limit of Linearity Range Changing the range ISM and LOG Modes or gain SSA Mode will change these limits For very low high level measurements it may be necessary to utilize a microphone having a higher
282. bringing up the prompt Add to Average View Back Return to the previous display e Graph Adjusts the vertical graph scale and offset Avg History The Avg History display shows a history of the spatial averages which have been stored using the Store function in the Spatial Avg check menu Use the View menu or the Spatial Avg check menu to access the Avg History display Occurrence date and time Display label Awg isni i888 14 08 55 Current average history record number p i Level in dB of selected filter 38 9 Bandwidth 1 1 or 1 3 oct M Selected filter frequency zm aaH Number of spectra averaged Spatial average history note field e Test 1 Total number of spatial average history records In order to clear the Avg History records an overall reset is required Avg History Check Menu 11 38 Use the up and W down arrow keys to move to the previous and next spatial average history records To manipulate the Avg History records press the check key to access the Avg History check menu The Avg History check menu is shown below 824 Reference Manual 9 29 09 If you are viewing an Avg History record use the average function to average records which are already in the average history together Remember that all records are weighted equally If you have an average history record which was com
283. bution Display label Live Windspeed gt Live Wind Direction p Windy Wind c ge z M is l E Windy Directional 5 Distribution Windy amp A 36x 2 5 72 The following explains each of the display s components Display label This shows the current display in this case Wind c Percent Live Windspeed The Live Windspeed is the instantaneous value of windspeed Live Wind Direction The Live Wind Direction is the instantaneous wind direction indicated in both compass coordinates and degrees Percent Windy Condition The Percent Windy Condition is the percent of the time the windspeed was above the Windy Threshold Level Windy Directional Distribution The Windy Directional Distribution is shown on a compass rose with indications of the percent of the time that windspeeds above the Windy Threshold Level were in the directions represented by each of the eight directional coordinates In this instance we can 824 Reference Manual 9 29 09 see that winds having levels above the Windy Threshold Level of 5 04 shown on the Windy b View were from the North West 5995 of the time 9 29 09 System 824 Views 5 73 5 74 824 Reference Manual 9 29 09 CHAPTER System 824 Virtual Instruments System 824 Virtual Instruments The System 824 presents a number of distinct virtual instruments enabling you to select the mode best suited to a particular ap
284. by choosing the long or short report Lowest Level 040 Selects the lowest SPL histogram level to be printed Highest Level 090 Selects the highest SPL histogram level to be printed Resolution 5 0 Selects the SPL histogram resolution Pk 1 Histogram No You can customize the Peak Histogram report by choosing the long or short report Lowest Level 110 Selects the lowest Peak1 histogram level to be printed Highest Level 140 Selects the highest Peak histogram level to be printed Resolution 5 0 Selects the Peakl histogram resolution Pk 2 Histogram No You can customize the Peak2 Histogram report by choosing the long or short report Lowest Level 070 Selects the lowest Peak2 histogram level to be printed Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 5 0 Selects the Peak2 histogram resolution Short Report This template shows the default settings for the Short Report The All Short Report prints all of the reports Those reports with a Short version are printed in the short form After selecting the template you can modify it as explained in Printing a Custom Report on page 8 23 8 14 824 Reference Manual 9 29 09 Short Report Template SSA instrument Report Settings Lower Level Report Settings Description Unformatted No A dump of all Read Query and Interval remote commands Multiple values are comma delimited Data Report Yes This show
285. bytes day from line 29 Run Log bytes day n number of Run Log records day n x 17 bytes record Setup RAM Registers bytes used 0 506 0 n number of registers stored TOTAL bytes used day 824 s Memory Size 2 000 000 TOTAL Run Time in days unti out of memory n x 506 bytes record Sum lines 25 to 31 31 977 2 047 485 Table E 6 Example LOG Memory Usage Calculation see TOOLS Memory Enter total memory shown divide line 38 by line 37 824 Reference Manual 9 29 09 824 LOG Memory Usage Worksheet Exceedance Memory Estimation Bytes Bytes Needed Basic Exceedance Record 32 Excd Time Hist n estimated number of samples 129 bytes max 21 n Wind Tach Yes 3 TOTAL Bytes Excd Anticipated Excd Day Add lines 1 thru 2 Enter Number TOTAL Excd Bytes Day Multiply lines 4 amp 5 copy to line 30 9 29 09 E 6 Interval Memory Calculation Bytes Needed Basic Interval Record Intv Save Ln s 34 18 Intv Save Ln Table 384 Wind Tach Yes 5 TOTAL Bytes Intv Sum lines 7to 10 Anticipated Intv Day Enter Number Calculated TOTAL Intv Bytes Day Multiply lines 11 amp 12 copy to line 31 Daily History Memory Calculation Bytes Used Bytes Needed Basic Daily Record 175 Daily Save 6 Ln Values 18 Daily Save Ln Table Wind Tach
286. can be enabled as an Overall measurement or as a function of each Interval History record To store interval spectral Ln levels set Spectral Ln to Interval enable Ln and Interval histories and set Intv Save Ln to Yes 7 22 Original Setting After Change and Sort L 1 Percentile 10 0 L Percentile 5 0 L 2 Percentile 20 0 L 2 Percentile 10 0 L 3 Percentile 30 0 Lp 3 Percentile 20 0 L 4 Percentile 40 0 L 4 Percentile 40 0 Lp 5 Percentile 50 0 Lp 5 Percentile 50 0 L 6 Percentile 60 0 L 6 Percentile 60 0 The Spectral Ln setting is used to measure six Ln values for each 1 3 octave The setting options provided are None Spectral Ln s are turned off Overall Spectral Ln s are computed for the over all measurement Interval Spectral Ln s are computed for each interval period NOTE If Random Corr is set to Yes and Spectral Ln is set to Interval then Spectral Ln will be set to None and the warning Setting Conflict 1s displayed 824 Reference Manual 9 29 09 LOG and SSA Triggering Settings For the SSA instrument these trigger settings are used to control the logic output line The Stats displays are only available to the LOG instrument Use the and W keys to move from one setting to the next Then use the D key to change the selected setting The key is used to return to previous menus SPL Excd Lvl 1 LOG SSA NOTE In t
287. ch will simplify making an RT60 measurement Both of these setups load the RTA instrument but with the triggering arm and end menus configured for two types of measurements The RT60 A and RT60 B RTA instruments are accessed from the SETUP key RT60 A The RT60 A setup is designed to gather data to measure an RT60 by exciting a room with a steady state noise It 1s configured in the following way Detector Linear Detector Time 0 01 seconds e Autostore Yes PreTrigger 50 Save ByTime Yes Triggering Yes Trigger Source 1 kHz Am Mode L gt Arm Level 80 0 dB Arm Time 2 0 second Trigger Mode L lt Trigger Level 80 0 dB Trigger Time 00 0000 seconds End Mode Time End Time 3 0 seconds optional 11 17 Then Stop RT60 B The RT60 B setup is designed to measure an RT60 by exciting a room with impulsive noise such as a gunshot or a balloon popping and is configured in the following way Detector Linear Detector Time 0 01 seconds e Autostore Yes e PreTrigger 10 Save ByTime Yes Arm Mode Now Triggering Yes Trigger Source 1 kHz Trigger Mode L gt End Mode Time End Time 3 0 seconds Then Stop Qualifying Background Noise Rooms RTA ID This ID sets up the System 824 to measure and evaluate background noise according to the RC and NCB room noise criteria 11 18 The System 824 has an Instrument Definition that mak
288. change the base level of the SPL history graph The following is the possible setting range 39 to 799 The Graph Scale setting allows you to change the vertical range of the SPL history graph using the following possible settings 2 1 1 2 1 4 1 8 dB per dot pixel Pressing the D arrow key on the Graph menu item allows you to adjust the graph settings through a menu A screen similar to the following appears Graph Level 666 Graph Scale C2 J Pressing the key Graph menu item from the SLM Check menu allows you to graphically and interactively adjust the Graph settings A screen similar to the followings appears 824 Reference Manual 9 29 09 Settings NOTE Refer to the Settings Description section and the individual instrument s Settings Menu Layout sections for details on the configuration options for this menu Controls Settings Menu Other SSA Check Menus NOTE The SSA Any Data check menu is the same for the LOG instrument Any Data Check Menu 9 29 09 Adjust Graph ud Scale 1 4E Level Sle Exit The Settings menu allows you access to the SLM settings area that is usually accessed from the SETUP key This is a shortcut to the SLM settings so you can modify the items in the SLM menu Allows you access to the Settings menu in the Controls area that is usually accessed from the SETUP O key This is a shortcut to the Controls sett
289. changes to Trigger Logic In state Time 824 starts recording an Autostore after Trig ger Time seconds Count The 824 starts recording an Autostore after Trig Samples of data have been received Trigger Level This level is used when the Trigger Mode is set to Level L lt L L gt This is the amplitude in dB at which the 824 will start recording an Autostore record It must be valid for the period of time set by Trigger Time e 0 0 255 9 dB Trigger Time When the Trigger Mode is set to Time this is the time that must pass before the 824 starts recording an Autostore record This is also a qualifier for the level settings If the optional 11 11 End Settings Menu 11 12 time is non zero then the level condition must be met for the specified time before the trigger will occur 00 0000 to 99 9975 seconds Trig Samples When the Trigger Mode is set to Count Trig Samples is the number of samples that will be taken before the 824 starts recording an Autostore record 0 65535 Trig Logic In When the Trigger Mode is set to Input the 824 starts recording an Autostore record when the logic input line changes to the Trig Logic In state Low High End Mode The measurement ends when the following conditions are met Never The measurement continues until the run stop key is pressed e L lt When the level is less than the End Level for
290. clarification of the values displayed 13 22 There are two Pulse FM displays The Pulse FM a display shown below is accessed from the THD display by pressing the down arrow key W arrow key 16 55 Hz 77 69 Hz 52 54 Hz 56 Hz 4B 41 3 Mod Rate SPL 82 5dBF The left and right arrow keys left or right arrow P can be used to toggle between the Pulse FM a and the Pulse FM b displays The Pulse FM a display shows all the required values for the calibration of the pulsed tone capabilities of an audiometer Present the pulsed tone at a proper level and press the RUN STOP key The stability of the measurement can be evaluated visually To retrieve data press RUN STOP again and read the values from the screen The following values are displayed rise time fall time on time off time plateau duration in milliseconds as well as overshoot in dB Rise Time B C time in milliseconds between the 20 dB point referred to the maximum level and 1 dB point on the rising edge of the pulsed signal envelope nominally between 20 and 50 ms Fall Time E G time in milliseconds between the 1 dB point and 20 dB point on the falling edge of the pulsed signal envelope nominally between 20 and 50 ms 824 Reference Manual 9 29 09 On Time J K time in milliseconds between successive 5 dB points of the envelope of the pulsed signal during which the signal is present nominally between 190
291. ct the 824 to the 824 Utility software To connect to the 824 Step 1 Attach the 006 to the 824 and to the serial port on the computer as described earlier Step 2 Start the 824 Utility program Step 3 Poweron the 824 Step 4 Press the Connect button on the tool bar Lm Close Select Port COMI z Select Baud Rate peo Status 9 29 09 Using the 824 Utility Software 10 3 NOTE See Communication on page 3 Step 6 Select the comport that your 824 is connected to 34 for details on changing the select the baud rate and press the connect button communication parameters on the 824 After a successful connection the setup window will appear with a system setup in the setup list box The 824 s serial number and title will be displayed on the setup dialog box screen 824 Utility an x File View Setups Data Help AAA l4 22 Sp Options Calib Power Date Time Controls Modem 15 System D 824 System Settings Instrument Labels Model Larson Davis Model 824 Serial Number 0138 Revision 3 128 23Jun2000 Instrument Type 55 Active Setup SLM amp RTA Instrument Name Enter Company Name Description 1 Enter Address Line 1 Description 2 Enter Address Line 2 For Help press F1 NUM 7 824 Utility Tool Bar The tool bar for the 824 Utility program provides support for the main functions of the 824 Utility program All
292. d they can be evaluated in a demo mode Restrictions of demo IDs Cannot print reports Cannot store data Cannot perform any I O commands Only 20 demos are permitted Memory must be purged prior to activating these IDs The following is an overview of how to select a measurement setup Step 1 display the available instrument setups press the Setup key GLH SLM I5H pr SSA P Lodgdg ing LOG Edit Settings tjj At any time one of the available setups will be the active setup The name of this setup will be at the top of the list below the Edit Setting message Pressing the key while the Edit Settings menu item is highlighted initiates the modification procedure 824 Reference Manual 9 29 09 After selecting a measurement setup press the M key to initiate the measurement Step 2 select the desired setup scroll through the setup list with the W keys until the item is highlighted then press Y It will be shown later how the Setup Menu can be utilized to modify one of the permanent setups to meet your requirements The 824 Utility software is also very useful for selecting and modifying setups Performing a Measurement SLM amp RTA SSA You can see from the top line that the ________ far meRTR 5 meter is in the SLM RTA mode and the bold SLM indicates that it is the SLM display or VIEW as we refer to it when using the Model 824 9 29 09 Witho
293. d for evaluation of equipment sounds See table below Flat Weighting A filter that does not adjust the levels of a frequency spectrum It is usually an alternative selection for the frequency weighting selection Center Frequencies Hz Weighting Network Frequency Response 1 3 Octave 1 Octave A B C 20 50 4 24 2 6 2 25 44 7 20 4 4 4 31 5 31 5 39 4 17 1 3 0 40 34 6 14 2 2 0 50 30 2 11 6 1 3 63 63 26 2 9 3 0 8 80 22 5 7 4 0 5 100 19 1 5 6 0 3 125 125 16 1 4 2 0 2 160 13 4 3 0 0 1 200 10 9 2 0 0 D 11 Center Frequencies Hz Weighting Network Frequency Response 1 3 Octave 1 Octave A B C 250 250 8 6 1 3 0 315 6 6 0 8 0 400 4 8 0 5 0 500 500 32 0 3 0 630 1 9 0 1 0 800 0 8 0 0 1000 1000 0 0 0 1250 0 6 0 0 1600 1 0 0 0 1 2000 2000 1 2 0 1 0 2 2500 1 3 0 2 0 3 3150 1 2 0 4 0 5 4000 4000 1 0 0 7 0 8 5000 0 5 1 2 1 3 6300 0 1 1 9 2 0 8000 8000 1 1 2 9 3 0 10000 2 5 4 3 4 4 12500 4 3 6 1 6 2 16000 16000 6 6 8 4 8 5 20000 9 3 11 1 11 2 Leq See Energy Equivalent Sound Level Sound Level Energy Average and Weighted Average Level dB A descriptor of a measured physical quantity typically used in sound and vibration measurements It is attached to the name of the physical quantity to denote that it i
294. d Selection menu without the need to use W to move the highlight down from the first item If one chooses to use the 4 D keys to move between Menus and prefers to enter each Menu with the first item Quick Start 4 21 highlighted simply use the amp key to highlight the first item in a Menu before exiting using the 4 D key to exit If you have been using the arrow keys to move between Menus and menu items and you feel you have gotten lost it is possible that you have entered a Menu where you do not recognize the displayed items because the highlighted item is rather far down the list Try using the key to move the highlight up to the first item and you may recognize where you are In general the items further down the list are for more advanced features and are less important for simple measurements Setting Control in the SLM View SLM settings can be adjusted from the SLM View screen activate the SLM view screen turn on the System 824 press the View key highlight SLM then press the Y Check key While viewing simple sound level meter data settings can be adjusted the fly without leaving the current display The following table describes the keys that are used to change settings 4 22 Action Range 18 Used in the ISM ingjrument Moves to the next setting instead of Gain Moves to the previous setting or Adjusts the current setting Enters the setting
295. d but erroneously declared as NiMH the charger will start for several seconds then will detect that they are not NiMH Charging will be terminated and the battery type changed to alkaline This safety measure will prevent primary cells from being charged and damaging the instrument due to leakage or explosion Nevertheless it is inadvisable to ever attempt to charge primary or non rechargeable batteries Rechargable individual NiMH cells can also be charged in an external rapid charger Introduction 1 19 Terminal Assembly Figure 1 9 Battery cover and compartment with alkaline batteries and Terminal Assembly installed Note location of Terminal Assembly Using the AC Power Adapter You may use an external power source via the external power connector using the provided power adapter The System 824 accepts 6 to 15 VDC and is internally fused at 0 5 A 1 20 824 Reference Manual 9 29 09 Overview This Chapter presents a general overview of the structure of the Model 824 an example of selecting a Setup or Instru ment Definition ID performing a measurement and storing the data Subsequent chapters will deal specifically with these steps in a more structured manner System 824 Setups or Instrument Definitions The System 824 was designed to be upgraded with instrument capabilities they are made available Please contact Larson Davis for information on the latest available upgrades 9 29 09 The
296. d by the Intv Spectrum setting Time History Sound Level parameters and spectral data measured and automatically stored at user defined time periods Run Log Displays the start and stop times dates of the active measurement Ln Centiles L1 L99 displayed for the measurement period 2 12 824 Reference Manual 9 29 09 As part of this exercise select each of these various VIEWs and use the W and keys to see how a variety of different parameters are displayed within each function We have sought only to explain the general concept of the VIEW function at this time More detailed explanations are provided later in Chapters 3 and 6 Data Storage and Recall Storing Data The Recall Files line only appears if data has previously been stored Recalling Data 9 29 09 When a measurement has been performed and the instrument stopped the measured data can be stored to non volatile memory before the instrument is reset or the setup changed otherwise the data will be lost Attempting to change the setup while there is measured data available will cause the system to prompt you to store the data before continuing Step 1 store measurement data press the ll DATA key The following menu appears Data Files Store File Recall Step 2 With the message Store File highlighted press the Check key to store the data Step 1 To recall stored data highlight Recall File
297. d to be printed 8 10 824 Reference Manual 9 29 09 Summary Report Template LOG instrument Histograms SPL Histogram No You can customize the SPL Histogram report by choosing the long or short report Lowest Level 045 Selects the lowest SPL histogram level to be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 5 0 Selects the SPL histogram resolution Pk 1 Histogram No You can customize the Peak1 Histogram report by choosing the long or short report Lowest Level 110 Selects the lowest Peak histogram level to be printed Highest Level 160 Selects the highest Peak histogram level to be printed Resolution 5 0 Selects the Peak1 histogram resolution Pk 2 Histogram No You can customize the Peak2 Histogram report by choosing the long or short report Lowest Level 070 Selects the lowest Peak2 histogram level to be printed Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 5 0 Selects the Peak2 histogram resolution Tailored Report This template shows the default settings for the Tailored Report The Tailored Report uses the settings from the Define Report menu under the O Setup key This allows you to create a custom report for any SSA or LOG instru ment ID The Tailored Report includes the Data Report Log Report Setup Report Interval Report Short Exceedance Report and the Daily R
298. dB option This provides a Leq time weighted average in accordance with European common usage in addition to compliance with U S Environmental Protection Agency EPA regulations 4dB The 4dB option results in Lpop time weighted average which complies with U S Depart ment of Defense DOD regulations SdB The 5dB option results in the time weighted average which complies with U S Occupa tional Safety and Health Administration OSHA reg ulations 6dB 6dB option results in the Lay time weighted average which provides a convenient repre sentation of the long term average noise level as opposed to the RMS noise level Using ID Setting Files 7 19 Crnt Threshold SSA ISM LOG In the ISM instrument the Crnt Threshold setting is a submenu to the SLM menu selection This setting affects the System 824 5 secondary or current buffer Crnt Criterion LOG LOG and SSA Ln Settings Ln Settings are available in the Logging SLM LOG and SLM amp RTA SSA instruments 7 20 The Crnt Threshold sets the threshold for computing the current time weighted average In compliance with the requirements of various regulatory agencies only those sound levels which are above a certain threshold level are used when computing the TWA Accordingly this setting can take on any integer value within the following range 0 255 dB For hearing conservation measurements set the threshold to
299. dance record in the order that it occurred The exceedance number indicates the order of the displayed exceedance in relation to the other exceedance records Exceedance Date Time The Event Date Time shows the time and date that this exceedance occurred Maximum Windspeed The Maximum Windspeed is the highest instantaneous windspeed logged during this exceedance event Direction of Maximum Windspeed The Direction of Maximum Windspeed is the direction of the maximum instantaneous value of windspeed logged during this exceedance event Maximum Reading The Max Reading shows the maximum level recorded during this exceedance You have the option of recording a time history for each exceedance by setting Time Hist to Yes under the System 824 Views 5 55 NOTE For a detailed description of Exceedance Time History settings see the section Logging SLM Exceedance History Settings on page 7 40 5 56 History settings via the SETUP key An exceedance time history will be recorded for every exceedance record An exceedance time history will only be recorded when all of the criteria have been met such as SPL Exceedance Level I Minimum Duration While displaying any of the Exceedance Displays a b or c the corresponding Exceedance Time History can be displayed by pressing the key twice A subsequent double click of the key will return the display to the corresponding Exceedance Displ
300. date and time when the overall measurement began and the date and time when the last measurement ended These times are not affected by the automatic reset or the manual Current reset but are reset with an OverAll reset The total running time is also displayed This is the total elapsed time of all measurements since the previous OverAll reset Display label Overall start date and time Mar 1999 12 41 27 Overall end date and time 9 mBWHan i999 12 42 44 Overall runtime tt J 11 Run Time gt Times L 2 16 53 824 Reference Manual 9 29 09 Trigger Views 9 29 09 The Trigger Display Views are accessed through the View key To select the Trigger Display Views press the View key The following menu will appear Use the up and WW down arrow keys to highlight Trigger Now press the D right arrow key to bring up the View Trigger display view menu View Trigger The Trigger display view offers 2 choices Status and Setup Use the Y check key to select the Status display Status The Trigger status display shows the current state of the RTA showing either Stopped Ready Armed Triggered or End This display shows a copy of the Live spectrum and its graph Also displayed is the repeat count when set to repeat or repeat with average and the number of samples gathered pre or post trigger RTA optional 1
301. date time 2 1997 11 62 55 Elapsed time to BH2Decl99 11 04 40 End date time Elapsed Run Time 0 01 33 5 28 The following explains each of the display s components Display label This shows the current display for example SLM Current b The display represents both Current b and Overall b display Start date time Date and time the current overall measurement began Elapsed time The Elapsed Time displays the length of time the current or overall measurements have been running It will restart at zero when the Reset key is pressed Current SLM only It will also pause when the Pause key 1s pressed and then continue when it is pressed again The timer 1s displayed as hhhhh mm ss s 824 Reference Manual 9 29 09 Current Overall SLM Display c Min Max End date time Date and time the current overall measurement ended or current time if still running The Current Overall c SLM or Min Max display consists of three major components Display label e Current Overall Lmax reading e Current Overall Lmin reading The SLM Current c or Min Max display is shown below Current Overall Current Overall Display label Current c X Lmax reading i mum 8 Bzpecio9 11 05 24 Lmin reading 1i n imum 4 6 BzDecil299 11 09 05 Current Overall SLM Display d Peaks 9 29 09 The following explains
302. de until the level is above the trigger level When in automatic mode the Automatic Gain Control will be activated When the gain is set to OdB it will be changed to 30dB when the signal is more than 45dB below the overload level for 1 5 seconds When the gain is set to 30dB the gain will be changed to OdB whenever the instrument becomes overloaded or the level is within 8dB of the overload level for 1 5 seconds The instrument will beep once when the gain is changed automatically to OdB and twice when it is automatically changed to 30dB Press the check key Q to open the Linearity RTA check menu shown below Linearit 1 Set Reference The Linearity RTA check menu contains the following items Set Reference Set the reference level to the current level i e zero the display Reference Lvl Reference level setting that may be entered manually AUD Optional 13 13 Linearity FFT Display The Linearity FFT display can also be accessed from the View Menu as shown in View Menu on page 13 5 Fundamental minusReference Fundamental Level Gain Changes the gain setting of the instrument Generally use OdB gain for levels at 70dB SPL and above and 30dB gain for levels less than 704 SPL The Auto Gain Control AGC function of the linearity displays step between 0 and 30 dB gain if the gain setting is something other than 0 or 30 the AGC function is inhibited Weighting This setting selects eith
303. default values used in the permanent setups these will also appear with the name defined for each at the time of storage If a previous setup had been created and saved this setup can be recalled by following the procedure described in Selecting a Measurement Setup on page 2 6 824 Reference Manual 9 29 09 Editing the Microphone Parameters The microphone to be used will either be a traditional condenser microphone which requires a polarization voltage or it will be an electret prepolarized microphone Further if it is a free field microphone and the measurement is best performed using a random incidence microphone the user can select to implement a random incidence correction to the measurement The procedure for selecting these parameters is described in section Customizing Settings on page 7 2 specifically the sections Transducer Setting SSA LOG ISM on page 7 8 and Random Incidence Microphone Correction Available to all Instrument types on page 7 8 Calibration The System 824 automatically changes the frequency weighting to C Weighting during the calibration process Therefore calibrators having frequencies which correspond to the flat region of the C weight curve 200 Hz 1 25 kHz may be used Larson Davis recommends the following sound level calibrators Larson Davis Model CAL200 94 114 dB 1 kHz Larson Davis Model CAL250 114 dB 250 Hz The procedure for performing a calibration
304. defines Leg as follows Equivalent continuous A weighted sound pressure level also average A weighted sound pressure level is defined as follows h Lar 10lg 2 2 dB Aeq T TJ 4 0 where L is the equivalent continuous A weighted sound pres Aeq T Mn sure level re 20 Pa determined over a time interval T t 0 is the instantaneous A weighted sound pressure of the sound signal Po is the reference sound pressure of 20 Pa When a frequency weighting other than A is used the fre quency weighting used shall be included explicitly in the 9 29 09 B 1 title and the formula of the quantity for example equivalent continuous C weighted sound pressure level bh lf 2 2 Lo 55301 A p dB f If no frequency weighting is used the quantity is simply called equivalent continuous sound pressure level The Larson Davis System 824 calculates many time inte grated levels or time weighted averages TWA based on different parameters and time intervals They are all designed and programmed to perform the equation specified in IEC 804 above with allowances for the following A C and Flat frequency weighting characteristics Various interval times both fixed interval TWAs and vari able interval event TWAs Exchange rates or doubling rates can be entered that effect certain TWA measurements Certain TWA measurements include a programmable thresh old with only levels ab
305. delete these project settings within this menu You can also 9 29 09 If data from a previous ID was not saved you will be prompted to do so at this time If settings to the current ID have been made you will be prompted to save the ID at this time The ISM and AUD instruments do not issue these prompts define a project ID on a computer using the 824 Utility soft ware and then install it into the instrument where it may be selected for use For example one project may require the simple SLM where no data logging is performed and the weighting and detector controls are available in the data dis play rather than in a menu Another example may be an hourly statistical measurement set to run for 8 hours using a LOG ID To select an instrument definition ID use the W keys to highlight the desired ID Press the Y key to select and activate the it The Setup menu then closes and the main display appears The modification of a selected ID to meet the requirements of a particular measurement application is an entire topic in itself which will be addressed in general in the next chapter and in detail in later chapters individually describing the setup and operation of each of the instrument types available for the System 824 However once these modifications have been made the new ID is named and stored as described in the following section Use the Setup Tools menu to create new IDs do this press the SETUP Ke
306. e ment Beginning Displays the Data File Summary of the first stored data file Ending Displays the Data File Summary of the last stored data file Find Allows you to find and display a Data File Summary by entering its associ ated Data File Number Purge Data Gives you the option to completely Files remove from memory all stored data files Selecting and Modifying Instrument Definitions IDs As explained in the section System 824 Setups or Instrument Definitions on page 2 1 the way to prepare the System 824 for a measurement is to select an existing Setup or Instrument Definition ID from the list which appears on the display after pressing the Setup Key O and either use it as is or modify it to suit the requirements of the measurement to be performed In this section we will explain in general how an ID is modified and stored using the Setup Menu of the System 824 More detailed descriptions for specific Instrument Types e g ISM LOG or SSA will be provided in later chapters When a PC is available the 824 Utility software is a very powerful tool for creating and storing new IDs and uploading them to the System 824 for use 4 12 824 Reference Manual 9 29 09 The Setup Menu The Active ID 9 29 09 Pressing the Setup key will produce a display similar to the following Logg ing LOG The first item in the list is the Active ID which will be highlighted If the user exits fro
307. e It is expressed in Pascals squared seconds when the exchange rate is 3 dB where q is the Exchange Rate Factor See Exchange Rate L q CSE 7 10 Standard ANSI 1 25 It is the sound level which if continually applied for the Criterion Duration will produce a Noise Dose of 100 The current OSHA Criterion Level is 90 dB Standard ANSI 812 19 It is the level of a constant sound over the Criterion Duration that contains the same sound energy as the actual unsteady sound over a specific period The period is generally shorter so the sound energy is spread out over the Criterion Duration period Example If the Criterion Duration 8 hours and the specific period is 4 hours and the average level during the 4 hours is 86 dB then the 83 dB A rating of community noise exposure to all sources of sound that differentiates between daytime and nighttime noise exposure The equation for it is 9 29 09 L de x 1010510 0700 1900 2200 2400 1 L 10 10 Lj 10 L 5 10 10 10 242 DX 0000 Lan 1010510 0700 1900 2200 0700 2200 2400 1 Lj 10 10 1 10 1 10 10 24 10 10 10 0000 0700 2200 The continuous equivalent sound level See definition is generally calculated on an hourly basis and is shown in the equation as L Decibel dB The values for the hourly periods from midnight to 7 a m have 10 added to them to represent less tolerance for noise during sleeping hours The sa
308. e accessed from the Linearity FFT display by pressing the down arrow key V latness FFT i 0 08 fak 10 5 Level Reference 5 245 Y5 2 B The Flatness FFT display shows the relative level of the highest FFT bin the true frequency of the input signal derived from the FFT data and the THD plus noise metric The frequency weighting for this display is forced to Flat regardless of the Weighting setting This display is used to measure the frequency response of an audiometer The highest amplitude FFT bin is found and its level is displayed in the lower left corner of the display The chosen reference level is displayed in the lower right corner A precise measurement of the frequency is displayed to the center right of the display If the level is greater than the trigger level setting the THD plus noise value will be displayed in the upper right corner The example display shown above is for a measurement at 1kHz Measurements at SkHz and 125Hz would appear as shown below latness FFT 5 THD nh 4 dB Reference 79 346 7 75 2 08 824 Reference Manual 9 29 09 THD Display THD n percentile THD latness FFT X THDb n 39 15 6 Reference 114 3dp 75 2 4 The operation and menus for this display are the same as Linearity FFT please refer above for operation instructions The THD display shown below is accessed from the Flatness FFT display by pressing the down arrow ke
309. e any of the system settings or IDs that you want to be permanent The Delete Last feature will allow the user to delete the very last record stored in memory from any instrument type It also allows you to recall a file delete individual records within that file run the instrument again and append new data to memory Essentially the record is unstored from memory The memory structure of the 824 is a forward and reverse linked list This means that for each type of data there is a pointer to the first record and a pointer to the last record and 3 29 Deleting the Last Stored Record If View Back is selected you will be returned to the last view screen displayed If nothing is selected after a 30 second time period this screen will disappear and return to the previous display 3 30 that each record points to the next record and the previous record This structure makes the memory very efficient compared to fixed sector file allocation table based mem ory structures and sequential forward and reverse data retrieval is very fast This memory structure does not allow us to delete data in the middle of used memory in a way that would allow it to be reused However there is no problem deleting data from the last to the first Step 1 delete the last stored record press the TOOLS 2 key to access the TOOLS menu The follow ing menu appears key Purge ALL Data Files Delete Last
310. e currently selected detector Elapsed measurement time shown as mm ss ss h mm ss or hhhhh mm SLI 0verAll a F 43 3A inn Bo gt S low SPL 9 29 95 I Overall time weighted average Leq in this case Time weighted average TWA descriptor for The System 824 s Logging SLM Overall e display shows the overall measurement period and TWA In this case the measurement is Leg because of the 3dB exchange rate The quantity is A weighted and has a measurement elapsed time of 11 43 1 11 hours 43 minutes and 1 second OwerAll e 5 TWA Ley 52 2 the overall measurement Overall exchange rate Overall sound exposure level SEL EF SEL 86 6 Elapsed measurement time shown as mm ss ss hh mm ss or hhhhh mm 9 29 09 BH 11 3d3 1 The actual equations used within the analyzers are based on that for IEC 804 and are implemented according to this equation 41 Lowa Leart ko log 0 log a 8 1 where Lg is the current SPL at sample s for measurements that include a threshold is set to x if L is less than the Threshold Level L k is the exchange rate constant which is equal to 10 00 for an exchange rate of 3 dB Leq 13 29 for an exchange rate of 4dB Lpop 16 61 for an exchange rate of 5dB 20 00 for an exchange rate of 6dB L Avg n is the total nu
311. e ext ene AN SR et eves WEN ak hance EE 7 40 Exchange Rate glossary n RR rt aede dee Re E RR ETE eet D 8 Exchange Rate Factor glossary tec UR a en ee e a e D 8 Exposure Check Menu zr ERE Oeo apr d 7 73 S net orte 5 31 Exposure Factor AOE e D 8 Extetnal Powers EU E Fr EC Cp RR 1 18 External PowerSource oe ee e er d di E REO epe hPa 1 20 F Fall et aeq an p eed 13 22 Far DNE D 9 D 9 geometric ERIS IER cen m AU RE ODE D 9 Eeat tes eee e eed P P vcrb tete p 1 7 FFT Bandwidth ed e etate eee ete tete 12 3 Calibration 5 ede ee 12 13 Changing dB Reference 12 13 Check M rida oA dee edad eine la e 12 8 C ount AYeraglng eere deer eerie ao edet oap eher rex 12 4 dB reference level ioi e RE ete bed eset REIR Ee cene Pies 12 17 Display sse oae e Pvt dde edam deditio ets 12 6 Display n Lanear Units ccc NN ede HE e n ette ee nai 12 14 oe Pn ete ed potete rere EE ETUR QI 12 17 ric m 12 1 Gam Settings x see A datu don ee 12 3 Getting linear units In DNA
312. e of each run stop Setup Report No Print the settings and their values for the LOG instrument SPL Histogram No The 6 Ln values Lmax Lmin and a bargraph of the level distribution Intv Report Short Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in he short report The Long reports adds the Ln values for the Interval period Hist Report Yes Leq for each time history period Report Short Lists number of Record Exchange Rate Minimum Duration Time Period Mode Start Time Leq Max Peak Overloads Unweighted Peak Duration SEL and Spectrum Daily Report Short Lists date duration Leq Peak Unweighted Peak Ldn Lmax CNEL and Lmin 9 29 09 Printing a Report 8 13 Tailored Report Template LOG instrument Print Range Intv Report Short You can customize the interval report by choosing the long or short report Lowest Record 00000 Selects the lowest interval record to be printed Highest Record 65535 Selects the highest interval record to be printed Hist Report Yes You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time history record to be printed Highest Record 799999 Selects the highest time history record to be printed Histograms SPL Histogram No You can customize the SPL Histogram report
313. e overall Spectral LN data while the 824 is running the message Calculating Stop to View will be displayed The 824 has peak detectors for A C and Flat frequency weighting that measure simultaneously the greatest instantaneous level Lpy that has occurred since the last current or overall reset Some histories and event counters are only able to evaluate one of the three peak detectors The Peak Weighting Setting selects which is to be used for these features Peak Weighting allows you to select either A C or Flat weighting for the primary peak detector PK I This setting provides the following three options A The A weighted peak detector is used C The C weighted peak detector is used Flat The Flat Weighted peak detector is used With the RTA Detector setting you can set the time averaging characteristics for real time frequency analysis This setting provides the following two options Slow The frequency analysis uses exponential averaging with a one second time constant Fast The frequency analysis uses exponential averaging with a 1 8 second time constant which allows more variability to appear in the measure ment Using ID Setting Files 7 9 RTA Weighting SSA Bandwidth Setting SSA NOTE The SSA instrument only measures data using 1 3 octave filters When 1 1 octave filtered data have been selected the energy in 1 3 octave band data are summed to give octave filter data When using the
314. e te Ra 9 12 Calibration totae tn didam dfi 9 3 Exceedance Measurements Sound Level Measurement Level Trigger 9 17 Danearity o i reU reed deed veia trees Gees eei 9 13 ERE Ee ROS 9 15 Measurement Mode s np epe tetete fio Rite eee a ep enna Ae 9 1 Measurement Pardmeters 5 us rese rero Pere Xr 9 5 Measurement Ranges 55 oh dp teet ille or pelea d e eate td 9 9 Microphone Parameters eec de e e RR I ee e EE Reds 9 3 Noise FIG ite ete een bete ine M pee n teer bet 9 4 Overload 2 eR RU eR Oh ea a e eR RE UR OR 9 14 Overload Reset 5 ostro e i ERE EN E ES 9 14 Performing ctim e REVO ER OR e coe e ERE ER EXE 9 11 Positioning ete oet atte ee EGRE Ee Gein M EET ces ER Ie ubi b oe ettet deus 9 7 Preset Integration Time ise eee tereti eie dc ie ipe een 9 16 Model 831 Technical Reference Manual Index 1 SEM Display erc Timer Mode ea nee Under Range reiten Windscreen tte oie Sound Power Level sss Sound Pressure Level see Sound Sound Speed esee eden Spatial Average sec cvs sessteia teen ee e ete Specifications AC DC AC DC Output ISM LOG AC DC 58 AUD Mode ERU cable driving capacity pener
315. e template you can modify it as explained in Printing a Custom Report on page 8 23 8 8 824 Reference Manual 9 29 09 Summary Report Template SSA instrument Report Settings Lower Level Report Settings Description Unformatted No A dump of all Read Query and Interval remote commands Multiple values are comma delimited Data Report Yes This shows general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Setup Report No Print the settings and their values for the SSA instrument Intv Report No Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in he short report The Long reports adds the Ln values and Spectral LNs for the nterval Hist Report No Leq for each time history period Print Range Intv Report No You can customize the interval report by choosing the long or short report Lowest Record 00000 Selects the lowest interval record to be printed Highest Record 65535 Selects the highest interval record to be printed Hist Report No You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time history record to be printed Highest Record 799999 Selects the highest time history record to be printed Histograms SPL Histogram No Pr
316. eading 824 Reference Manual 9 29 09 Any Level Check Menu 9 29 09 The Any Level c display shown below displays the Slow SPL Leq and SEL for the selected frequency weightings and the peak level with its frequency weighting Any Level c 0 SPL Slow Peak 96 64 70 fii Le SEL 06 8 68 24 00 13 78 Use the right and left arrow keys to step between the a b and c displays Press the check key Q to access the check menu shown below SLHA RTIB Gain H C H LA J The Any Level check menu items are Gain Changes the gain setting of the instrument Weighting This setting selects either A C or Flat frequency weighting for the sound level meter and FFT not used by the Any Level displays AUD Optional 13 9 Linearity RTA Display The Linearity RTA display can also Linearity RTA display shown below is accessed from be accessed from the View Menu as the Any Level a and b Displays by pressing the down arrow shown in View Menu on page 13 5 key W lnearitug 10 99 1509 Linearity display shows the level of the highest fractional octave RTA data relative to a set reference level Also shown are the filter frequency of the selected level and the RTA Bandwidth setting The frequency weighting set by the RTA Weighting setting is used Flat by default For testing attenuator linearity at 1 kHz it is recommended to use A weighting to reduce low frequency ambient noise
317. easurement The fol lowing screen will appear a The second function of the pause key is to remove unwanted data from the measurement The cursor is used for this fun citon The 4 D arrow keys move the cursor across the graph Once it is at the desired point press the Y key to delete the data to the right of the vertical bar After the instrument has deleted the unwanted data the measurement will resume automatically 824 Reference Manual 9 29 09 Preview Pressing the 10 PAUSE key when an instrument is stopped brings up a Preview display which allows you to view the SPL without affecting measured data Pressing the ID PAUSE key again will exit this screen or simply press the RUN STOP key to exit this screen and start taking a measurement Preview FN spL 48 9 9 Data HOT beina SEMI 9 0 aV Arrow Keys Pressing and holding an arrow key will repeat the actuation of the key The repeat rate increases as the key is pressed for a longer period of time Key pressure also has an effect on the repeat rate as does the amount of data available to view and W Up and Down arrow keys navigate from one item to another in a menu or from one record to another when displaying history data Pressing and holding an arrow key will repeat the actuation of the key These keys are also used to modify settings Use the key to step to the next higher number or character value and
318. ecked level Checked Level nnn n C2 Day Date and Time ddd ddmmmyyyy hh mm ss C3 Calibration Mode Manual Auto C4 Cal Status OK Bad C 101 Variables 1 4 66 824 Reference Manual 9 29 09 Time History Variables SSA LOG TAL Brackets in the syntax indicate optional characters and operands SSA LOG Leq RMS Level nnn n dB TAL H2 LOG Other level Pk I Pk IL or Lmax nnn n If Other Level is set to Advc then H3 SSA LOG Run time of sample hhhhh mm hh mm ss mm ss ss TAL H4 SSA LOG HISTORY BARGRAPH TAL H5 SSA LOG Return the advanced value where n The optional parameter n is n TAL comes from a list of available levels available only when advanced time history is enabled When n is omitted or 0 all enabled values are transmitted H 6 SSA LOG Return descriptive text for the n is an optional parameter when n TAL advanced level it is omitted or equals 0 the descriptive text for all enabled levels is returned H7 SSA Return Leq Live data from an n is the ANSI filter number for n advanced time history requesting a single filter level When n is omitted or equals 0 all filter levels are transmitted H SSA LOG Same as doing an H 1 H 5 0 101 TAL H SSA LOG Same as doing an H 1 6 0 102 TAL 9 29 09 A 67 For the LOG instrument type H5 and H6 are for when Othe
319. ecords that you don t want This menu option allows adjustment of the auto power off the contrast or viewing angle turns the backlight on or off and adjusts settings that control the power conservation fea tures Refer to the section POWER key on page page 3 3 for a full description of the Power Monitor settings In the following example of the Power Monitor display the battery indicates 3 49 V while charging When the instru ment is running this will typically be 3 6V or less Battery Battery Source EXT 15 Source IHT 45 Batteru Battery 644 External 11 20 External 6 3 Battery 3 94 Battery 5 950 5 BSa8 4 F 5 HiMH Charging Alkaline Front Panel Keys Functions and Menus 3 33 Communication The Communication display shows the status of the serial port i e how many minutes until the standby mode is auto matically enabled and the last characters received and trans mitted and is used when troubleshooting communication problems and as an aid when writing programs to control the instrument To access the Communication display use the or W key to select Communication from the Tools menu then press the Y key The following appears Indicates current address Shows the last characters received none in this example Shows the last characters sent none in a this example Shows the minutes of inactivity remaining before the serial i
320. ect and then press the Y key A locked symbol appears next to locked IDs in the Setup menu except for the current running ID and symbolizes that this ID is Write Protected Once the ID 15 write protected it cannot be changed or deleted until it is Write Enabled To delete an ID that has not been write protected use the or keys to highlight Delete ID then press the Y key The ID is removed from memory and the ID name is removed from the Setup menu To write enable or unlock an ID use the W keys from the Setup menu to highlight the desired write protected ID marked with a locked symbol Press the TOOLS key Press the Y key on the highlighted Write Enable menu option The locked symbol disappears next to the ID shown in the Setup menu symbolizing that this ID is write enabled Front Panel Keys Functions and Menus 3 17 Tools Key NOTE In certain situations you also use TOOLS key allows you to access controls and oper the TOOLS key to delete write ations such as calibration battery usage memory usage set enable or write protect instrument defi ting date and time timer or computer port settings You mions ID fr om the Setup menu as press the TOOLS key to access the Tools menu To mod previously described ify settings press the key on a menu item from the Tools menu Pressing the Y key on a menu item from the Tools menu allows you to view system settings and oth
321. ected ID Printer Report 3 Page 3 Line B lt O check key to abort the printing job 8 4 824 Reference Manual 9 29 09 Defining and Printing Tailored Reports In the System 824 Tailored Reports are available to the SSA and LOG instruments Selecting Tailored Report under the Print menu copies the report settings under Define Report from the Setup Menu for the SSA and LOG instruments for printing 9 29 09 With the System 824 a tailored report setting for each SSA or LOG instrument ID can be created i e each user can set up their own user defined print settings Therefore each SSA or LOG instrument ID can have its own pre set custom ized report settings This section discusses how to define and print tailored reports for the SSA and LOG instruments The following table shows the available settings for a Tai lored report for the SSA instrument Menu Item Options Unformatted No Yes Data Report No Yes Setup Report No Yes Intv Report No Short Long History Report No Yes The settings for a LOG instrument Tailored report are shown under Tailored Report Template LOG instrument on page 8 13 The following provides an example of how to define and print a tailored report Printing a Report 8 5 Step 1 Step 2 Step 3 Step 4 Press the Setup key to bring up the Setup menu Highlight the Edit Settings menu item and press D arrow k
322. ecting Open in Step 5 above the file record is deleted and now you are allowed to look at each individual record and decide whether to delete or store it with new data appended to it Follow these steps to delete individual records Step 1 The last display that was viewed will appear after selecting Open Front Panel Keys Functions and Menus 3 31 3 32 Step 2 Press the TOOLS 2 key and the following appears Step 3 Highlight Memory and press the right D arrow key to access the Delete Last function Purge ALL Delete Last TT Data Files Allocated IP s 810 Step 4 Highlight Delete Last and press the Check key The records will appear one at a time Below are examples of some of the records Delete Last L Excd CLOG 18 82 71 BB 33 SF bytes Free Memory 97 204 4620827 475149 Delete Last Delete Last Interval CLos RunLog TH LOGI B25ep1999 08 51 55 B25ep1999 85 51 59 05 5 bytes 24 bytes Free Memory Free Memory 99x 4656327 475149 gr 4656107 475149 To delete them press the Check key The following will appear 824 Reference Manual 9 29 09 Power Monitor 9 29 09 Delete Last a De lete View Back With Delete highlighted press the Check key again to delete the record The next record will appear Continue this process until you have deleted all of r
323. ector Frequency Weighting Secondary Parameter Frequency Weighting Although the System 824 measures the sound pressure level using multiple values of detector and frequency weighting it only displays a single value as shown above For this parameter you have a choice of three detectors averaging time Slow Fast Impulse and you have a choice of three frequency weightings A weight e C weight Flat Similarly you have a choice of three frequency weightings to be used for the display of the peak level 824 Reference Manual 9 29 09 A weight e C weight Flat The procedure for selecting these parameters is described in section Customizing Settings on page 7 2 specifically the sections Weighting Setting SSA LOG ISM on page 7 6 and Pk Weighting SSA LOG ISM on page 7 9 Positioning the Meter The meter will be either mounted upon a tripod or held in the hand In order to avoid the effect of sound reflections from the body of the operator interfering with the measurement the meter should be located as far as possible from the body Thus when actually performing the measurement the operator should place himself at a distance behind the tripod mounted meter or extend the hand held meter as far from the body as is comfortable If desired a microphone extension cable may be placed between the meter and the preamplifier microphone When doing so take care that the preamplifier micropho
324. ectrum with more detail See page 6 for more information Zoom out Allows you to see FFT spectrum with less detail See page 6 for more information 12 12 824 Reference Manual 9 29 09 FFT Calibration Acoustic measurements are in dB relative to 20 uPa The FFT spectrum always displays the measured level in decibels on a logarithmic scale In fact the use of the term level implies a decibel value relative to a defined reference value When the System 824 has been calibrated using an acoustic calibrator whether from the ISM SSA LOG or FFT instrument the decibel levels are relative to 20 uPa 20 micro Pascal Note however that it is possible to provide a digital readout of the amplitude at the cursor position in linear units as shown below in the section Displaying Amplitude in Linear Units on page 12 14 Calibrating dB to a Different Reference Calibrating to measure acceleration decibel units relative to acceleration unit e g m s fi s etc 9 29 09 For measurements of non acoustical parameters such as acceleration it is more appropriate to express the measurement in decibels relative to a different reference using units typical for that parameter This is easily done using a calibrator to excite the transducer to a known value The decibel level of a measured parameter is calculated as follows Lv 20Log iL W Vie where V measured parameter and reference value
325. ed 03 01 01 08 20 13 6 0 i C 47 C 48 Graph 29 824 in the YZ plane fitted with the 2551 microphone 8 kHz Larson Davis Model 2551 Serial 0099 Normalized to 1000 00Hz 8 0 xy Tested 03 02 01 16 31 06 by James Higley Note Prepolarized Microphone Reference Mic B4K Model 4123 Serial Number 1424039 Tested 03 01 01 08 20 13 0 6 0 dB Mic 7943 28 Hz 2 Graph 30 824 in the YZ plane fitted with the 2551 microphone 12 5 kHz Larson Davis Model 2551 Serial 0099 Normalized to 1000 00Hz 8 0 xy Tested 03 02 01 16 31 06 by James Higley Note Prepolarized Microphone Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 03 01 01 08 20 13 824 Reference Manual 9 29 09 Power Current Draw of 824 Using External Power LOG LOG SSA SSA Running with Running with Running with Running with backlight OFF backlight ON backlight OFF backlight ON Power Not Charging EARN Power Charging 3 30 W D o n 2 Charging 9 29 09 C 49 C 50 824 Reference Manual 9 29 09 APPENDIX Allowed Exposure Time Tj 9 29 09 Glossary This appendix contains technical definitions of key acoustical and vibration terms commonly used with Larson Davis instruments The reader is referred to American National Standards Institute document 51 1 1994 for additional definitions
326. ed The value of 05 is the level that has been exceeded 10 5 of the time during the overall measurement The Ln b display consists of five major components Display label Current record Ln Elapsed Time Ln graph The Ln Centiles b display is shown below for the LOG instrument 824 Reference Manual 9 29 09 Current 1 iau Elapsed Time 8 29 96 an Display label L r1 b Centiles 1005 82 Ade BO eoe Sec A lt a Ln graph NOTE There are two Lns per bar in the graph The higher of the two is graphed Stats Views 9 29 09 The following explains each of the display s components Display label Shows the current display for example Ln b Centiles Current Selects percentage of Ln to display 1 to 99 using the and arrow keys to move from one percentile to another Ln This display shows the current Ln value Elapsed time Shows the elapsed run time accumulated since the last current reset Ln graph Graph of Ln s from 1 to 99 1 being on the left 99 on the right The Stats View has three displays which can be accessed by simply selecting Stats with Check key from within the main View menu then cycling through the views with the D and 4 arrow keys until the desired display appears System 824 Views 5 37 Stats a Display The W arrow keys cycle between the
327. ed according to the state of the Pk Weighting setting Pk II The second level the instrument stores is the greatest instantaneous level Lpg detected by the sec ondary peak detector that has occurred during the time history period The secondary peak level is weighted according to the state of the Weighting set ting Lmax The second level the instrument stores is the maximum level Lmax that has occurred during the time history period Adve Stores up to 38 different parameters with each time history period which are user selectable such as Leq Peak Max Min Takt maximal battery voltage and temperature See Advanced Time History screens below In order to double the time history storage capacity it is possible to reduce the resolution of the Time History record from 0 1dB to 1 0dB 0 1dB Leq and the optional Other Level are stored with the highest resolution 0 1dB which requires 2 bytes of memory per level 1 0dB Leq and the optional Other Level are stored with 1 0dB resolution which requires only 1 byte per level stored Levels are rounded to the nearest integer 85 5 would be stored as 86dB and 85 4 would be stored as 85dB 824 Reference Manual 9 29 09 Advanced Time History LOG SSA n Hext Done SSA only if Takt is OFF NOTE RTA Leq and RTA Live are mutually exclusive allowing you to choose only one for each time history period SSA only NOTE If Spectral Ln is set to
328. ed Level Calculations on page 1 OvII Threshold LOG This setting affects the System 824 primary or overall buffer Ovll Criterion LOG 7 18 exposure level every time the exposure duration is cut in half This setting provides the following four options 3dB The default 3dB option is the most commonly used and results in the Leq time weighted average When a threshold of 0 is used It is used internation ally and for measurements that comply with U S Environmental Protection Agency EPA regulations 4dB The 4dB option results in the Lpop time weighted average which is used for measurements that comply with U S Department of Defense DOD regulations 54 The 5dB option results in the time weighted average which is used for measurements that comply with U S Occupational Safety and Health Administration OSHA regulations 6dB The 6dB option results in the Lay time weighted average which is merely a convenient rep resentation of the long term average noise level as opposed to the RMS noise level The Ovil Threshold setting sets the threshold for computing the overall time weighted average TWA As per the requirements of various regulatory agencies only those sound levels which are above a certain threshold level are used when computing the TWA Accordingly this setting can take on any integer value within the following range 0 255 dB For hearing conservation measurements
329. eference Manual 9 29 09 9 29 09 16 61 for an exchange rate of 5dB lt or 5dB log 2 20 00 for an exchange rate of 6dB Layg or Y 6dB log 2 n is the total number of samples taken in the measurement the sample rate is 32 samples per second Tc is the criterion sound duration as set by the System 824 s Criterion Time Hours setting which by default is set to 8 hours since the time base for the instrument is 1 3204 sam ples per second the number of hours is multiplied by 115200 to make samples per hour 60 minutes hour times 60 seconds minute times 32 samples sec equals 115200 sam ples second Lc is the criterion sound level as set by the System 824 s Overall Criterion or Current Criterion settings Addition of the term log 100 was used to implement the 100 multiplier of the ANSI equation that creates the percent age Subtracting the log of the Criterion Time was used to implement the division of Criterion Time of the ANSI equa tion Projected Dose in the analyzers is obtained with an equation similar to that of Dose except that the actual duration time of the measurement is used rather than a Criterion Time as thus k Lc log ye log n log 100 5 1 PROJDOSE 10 where the log r is the actual time factor n being the total number of samples taken B 8 824 Reference Manual 9 29 09 APPENDIX Technical Specifications The specifications con
330. el SENEL Lax Sound 9 29 09 See Sound Exposure The Average Sound Level calculated in accordance with the Occupational Safety and Health Administration Exchange Rate and Threshold Level A part of the sound level meter that matches a particular model of microphone to the meter It must be chosen in conjunction with a microphone and a cable that connects them It is the Noise Dose expected if the current rate of noise exposure continues for the full Criterion Duration period The total sound energy over a specific period It is a special form of the Sound Exposure Level where the time period is defined as the start and end times of a noise event such as an aircraft or automobile passby The rapid oscillatory compressional changes in a medium solid liquid or gas that propagate to distant points It is characterized by changes in density pressure motion and temperature as well as other physical quantities Not all rapid changes in the medium are sound wind noise since they do not propagate The auditory sensation evoked by the oscillatory changes Difference between sound and noise Sound is the physical phenomenon associated with acoustic small pressure waves Use of the word sound provides a neutral description of some acoustic event Generally noise is defined as unwanted sound It can also be defined as sound that causes adverse effects on people such as hearing loss or annoyance It can also be defined as the so
331. el menu in the Time History menu In this case the value of this particular parameter will always appear in the same position as shown by the Lmax display in the figure above Alternatively the user could select from as many as forty different parameters which could include sound pressure levels with different weightings A C or F and different averaging times S F I RTA Spectra and even some non acoustic parameters such as Wind Tach data Temperature 824 interior External Voltage and Battery Voltage Setting up for multiple other levels requires the use of the Advnc TH menu in the Time History menu The selected parameters will be displayed in the same position as Lmax in the figure above Use the 43 and arrow keys to scroll through the other selected parameters The following shows how six different values of other parameter can be displayed on one particular Time History View by using these arrow keys The graphics on the second row indicate Windspeed Wind Direction and Temperature measured using a temperature transducer inside the System 824 System 824 Views 5 43 SLM Time History SLM Time Historu SLM Time History RECORD 5 RECORD 5 RECORD 5 ann BF a 100 OF 100 OF g 100 ED dB 80 dB 80 66 gn 66 gn bb A gn 66 3dBR 65 3dBC i 65 TdBF aj Leq 20 2 Leq 2 SLM Time History SLM Time History SLM Time History RECORD 5 A RECORD E ame RECORD E aon ED BD dB
332. ement x Received 2944 bytes Status Read 128 byte block 23 The next file can now be selected the destination folder specified the file name entered and the data downloaded A downloaded file will be stored with If you only selected Save Binary Data the downloaded file the file extension slmdl Sound Level must be translated by the 824 utility software to be viewable Meter Down load The first file in the measurement list If you selected Save Binary Data and Launch Viewer of will be viewable in the spreadsheet the Binary file will be saved and a spreadsheet pro or text program To view the other gram or text file program will automatically be opened records they will have to be selected and opened in the viewer program If you selected only Launch Viewer of the Binary from the directory where they are file will not be saved and a spreadsheet program or text file stored program will automatically be opened Explanation of files in the 824 Utility Directory In the 824 Utility directory C ProgramFiles LarsonDa vis 824 Utility you will notice 3 different types of files slmdi binary e csv spreadsheet file txt text file 10 24 824 Reference Manual 9 29 09 The binary files for each virtual instrument ISM SSA LOG RTA FFT AUD TAL have the following default file designations 28Junl 5i sImd the measurement The default file name uses the date
333. en averages it in accordance with the time weighting characteristic and then takes the square root This results in an amplitude described as rms root mean square It is the constant sound level that would expose a person to the same Noise Dose as the actual unsteady sound levels The equation for it is D Let ghogio gt NOTE This definition applies only for a Criterion Duration of 8 hours Standard ANSI S12 19 The level of a constant sound over a specific time period that has the same sound energy as the actual unsteady sound over the same period T pp ae as 1 Leg 1010210 OTI pat where p is the sound pressure and the Measurement Duration specific time period T T T See Sound Exposure Level It is defined in ANSI S1 25 as the change in sound level corresponding to a doubling or halving of the duration of a sound level while a constant percentage of criterion exposure is maintained The rate and the factors are given 824 Reference Manual 9 29 09 Far Field Free Field Frequency Hz rad sec 9 29 09 in the table below Standard ANSI S12 19 Exchange Rate Q Exchange Rate Exposure Factor k Factor q 3 01 10 1 4 13 333 75 5 16 667 60 6 02 20 50 There are two types of far fields the acoustic far field and the geometric far field Acoustic Far Field The distance from a source of sound is greater than an acoustic wavelength In the
334. en use a level of 94 dB so they generate a sound pressure of Pascal If the sound pressure level 76 3 dB then the sound pressure is 76 3 20 3 815 6 2 185 20910 20910 20 0 0065 0 13 Energy Average Leg The value of a steady sound measured over a fixed time period that has the same sound energy as the actual time varying sound over the same period This descriptor is widely used It is a fixed average See Sound Pressure Impulse The value of an impulsive sound The reading will depend on the time weighting applied Unweighted Peak The peak value of a sound with a meter that has flat frequency weighting and a peak detector Weighted Peak The peak value of a sound with a meter that has a frequency weighting other than flat and a peak detector The sound power emitted by a sound source It is measured in Watts The logarithmic form of sound power It is also expressed by attachment of the word decibel to the number The logarithm is taken of the ratio of the actual sound power to a reference sound power which is 1 pico watt Sound power level cannot be measured directly but can only be deduced D 21 Sound Speed c Spectrum Frequency Spectrum Threshold Sound Level Lt Time Weighted Average Sound Level TWA Lrwa TC D 22 through measurements of sound intensity or sound pressure around the source The equation for it is ee w 0 10 0 The speed at which sound waves propagate
335. eo to Ro ex 4 15 Wntesprotected TDSs i son eerte eh a TRUE 4 16 Preparing for a Measurement sse eene 4 16 Sel ctitig a Different ID RT ee 4 17 Accessing the Settings Menu ccccccscssesseessessesseceeeeeeeeceeserseseeseeneecaeeeneenees 4 17 Accessing the Settings Menu to Initiate Editing or Modification 4 18 Setting Control in the SLM View sse 4 22 System 824 Views 5 1 Status Icons and Indicators 5 2 Iac C e 5 4 SEM VAC WS itt tite tt Aba ans 5 5 Any Data View isis ee nine diee ipu 5 8 Any Eevel Form t iu RT OHIO Ue 5 8 Any Impulse Format sess 5 8 Any Lime Formate uS 5 9 SSA 5 9 SSA Displays utebare estet re bre t 5 11 824 Reference Manual iii iv SSA Displays Including 1 1 or 1 3 Octave Spectral Data 5 11 Fabula SSA VIEWS dt on nee b p ein ta uita cutis 5 12 Time History Displays ssssssesseseeeeeeeeneeen nennen 5 13 SSA iit iain ete E n Up UR deti pot eed 5 13 SSA Time History 24 1 2021020202 1442200000000000000000000000 0 5 16 RUM LOG 5 19 NAC ent les aks Heh tes eee e
336. eport 9 29 09 Printing a Report 8 11 After selecting the template you can modify it as explained in Printing a Custom Report on page 8 23 Tailored Report Template SSA instrument Report Settings Lower Level Report Settings Description Unformatted No A dump of all Read Query and Interval remote commands Multiple values are comma delimited Data Report Yes This shows general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Setup Report Yes Print the settings and their values for the SSA instrument Intv Report Short Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in the short report The Long reports adds the Ln values and Spectral LNs for the Interval period Hist Report No Leq for each time history period Print Range Intv Report Short You can customize the interval report by choosing the long or short report Lowest Record 00000 Selects the lowest interval record to be printed Highest Record 65535 Selects the highest interval record to be printed Hist Report No You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest interval record to be printed Highest Record 799999 Selects the highest interval record to be printed Histograms SPL Histogram No Prints SPL histogram a
337. eq time histories show the true dynamics of the signal without the residual decay effects of an exponential detector For example if you measure a sonic boom with a fast Leq time history it can show the two impulses of the N wave and possibly even an echo or two On the other hand the older instruments will show one pulse that may take upward of 20 seconds to return to the background level Bad If you are comparing data from traditional instruments it is important to be aware of this phenomenon but it is not necessarily bad If the Leq values being compared are of long duration one minute or longer then there is little blur caused by the exponential detectors of the older instruments and the data are very comparable If I choose to save C weighted SPLs every two seconds in the LD824 s Time History what am I getting You get the instantaneous SPL at the end of the two second period How does this compare with C weighted Leqs The Leq is the true equivalent level for that two second period as if the signal level were constant amplitude Detailed Explanation So what s the difference between sampled SPL and an Leq for the same period It depends on whether you are using 824 Reference Manual 9 29 09 Question 8 9 29 09 fast or slow SPL and the dynamics of the signal of course but the concept is still the same It all goes back to your statistics classes and sampling theories For an integration to be accurate it
338. er C or Flat frequency weighting as a filter prior to fractional octave filtering Trigger Level The Trigger Level setting defines the level below which the automatic frequency lock becomes active The Linearity FFT display shown below is accessed from the Linearity RTA display by pressing the down arrow key to produce the display shown below Inearilty THEA 75 27 decns Reference Frequency Level Reference 75 2 cB 7 B Ade Reference Level 13 14 The Linearity FFT display shows the relative level of the highest FFT bin and the true frequency of the input signal derived from FFT data The frequency weighting selected by the Weighting setting is used A by default to offer reduced out of band noise influence This display is used to measure the attenuator linearity of an audiometer The highest amplitude FFT bin is found and its level is displayed in the lower left corner of the display The chosen reference level is displayed in the lower right corner A precise measurement of the frequency is displayed to the center right of the display If the level is greater than the 824 Reference Manual 9 29 09 9 29 09 trigger level setting the THD plus noise value will be displayed in the upper right corner To set the reference level to the current level first press the check key to display the check menu shown below Set rence Lgi Reference Lvl 66 Gain 01 Weight ing Then highli
339. er System 824 Views 5 61 Daily d Windy Percent Display 5 62 of the displayed Daily record in relation to the other records A new daily record is created each new day A day is defined as 12 00 midnight to 12 00 midnight Duration The Duration shows the length of time represented by this Daily View measurement may have been stopped before the complete 24 hour period Average Windspeed The Average Windspeed is the numerical average of the windspeed over the duration of this record Maximum Windspeed The Maximum Windspeed is the highest instantaneous windspeed logged during this record Direction of Maximum Windspeed The Direction of Maximum Windspeed is the direction of the maximum instantaneous value of windspeed logged during this record Time of Maximum Windspeed The Time of Maximum Windspeed is the time hh mm ss when the maximum windspeed occurred Wind Exceedance Data The Wind Exceedance Data includes the value of the Wind Exceedance Level in this instance 40 11 and the number of times the windspeed exceeded this level Windy Threshold Data The Windy Threshold Data includes the value of the Windy Threshold Level in this instance 5 04 and the percent of the time that the windspeed was above this level The Daily d Windy Percent display consists of 4 major components Display label Record Number Date e Percent Windy Condition Windy Directional Distribution 824 Reference Manual
340. er displays NOTE From any of the following dis The Tools menu provides the following seven options plays the W arrow keys will which are afterwards described in greater detail step to the next or previous display in the list Menu Item Available Settings Options Setting Screens p key from Jools menu QD key from Tools menu About Name company name a System revision information Name address line 1 b User information Name address line 2 c Installed instrument options Title 30 characters Date Format Normal or ISO 8601 Takt enables Takt functional ity Yes or No Calibration Check Calibration dates times and measure Change ment when checked or changed Cal Level Calibrator S N Noise Floor not all versions 3 18 824 Reference Manual 9 29 09 Clock Timer Current Time Current Date Day of Week Timer Mode Run Date Stop Date Run Time 1 Stop Time 1 Run Time 2 Stop Time 2 a Current time date and time of next action b Timer mode status and settings Memory Delete Last Purge Data Files Allocated IDs Create EEPROM Backup a Memory status amp current instrument record information b Overall record status Power Monitor Display Power Status Power Settings gt Power Off Mode Auto Off Time Standby Time Backlight Time Backlight LCD Contrast External Power Min Battery Activate Battery Charger Type Battery and ext
341. er current draw reat eee ete ni t sei E inte Reb olay C 49 External power current draw 4 esee i hens G 3 Internal cou has see Aas te oh inibi 1 18 Q 3 3 MONOT X 3 33 power conservation eR eei er ere e E ERR Coe dee ee eae 3 8 Set ngs er ERI E 3 6 SNPS ee a 3 6 Powertng Up ste tos stone tees egent Mh eet Wied esa idt A Ae 4 1 No Display zu Re RR ie eee 3 4 Preamplifier d einer DER ema etl ene dae e Deom ete UBER rei tes D 17 input COBnector ttn p OE Se te ee DESNUDA nad 1 13 Preparing for a Measurement ocni sede decederet 4 16 Preview Display ree eg be eie d REOR e GN tue tena od 3 11 Print a 3 37 Printing All Long Report eee eicere Ue UR EH RU ER DH tree de 8 14 AIL Short Report E tee EP eR etd edades 8 14 CustomReportes cc re HR otio reiten etr center opt Hee oem WEN Ene the eee 8 23 R call Format H 8 7 Reports tete E REO on RI reed epe e e etg 8 2 RAE RGD OLES NI HH 8 26 serial printer connection eene e ERR Cate eleven UE ee e RE ee d 8 1 Summary REPON csse te ere o
342. erberation Time Settings If Note ends with a numeral it will be incremented automatically with each spatial average snapshot taken or stored 11 16 RT60 dB Down The automatic RT60 algorithm will search for a point 5 or more dB down from the maximum sample and then calculate an RT60 between that point and the next point RT60 dB Down Example If RT60 dB Down is set to 30 dB the RT60 will be calculated for the data between 5 and 35 dB down from the max The available selections are 5dB 10dB 5dB 20dB 25dB 30dB Auto RT60 The Auto RT60 setting when enabled automatically calculates the RT60 for each filter on screen as the user moves between filters using the up and down arrow keys Note An 8 character note field is provided to annotate a spatial average This is useful when describing the measurement you are taking and keeping track of different measurements or their location 824 Reference Manual 9 29 09 RT60 A and RT60 B Instrument Definition The RT60 A Setup is configured for the use of a steady state noise source which is shut off to initiate the decay The RT60 B Setup is configured for the use of a noise burst such as a balloon bursting Although the settings are predefined in RT60 A and RT60 B they can be changed at any time and used as customized setups for a personalized RT60 measurement 9 29 09 The System 824 contains two special RTA IDs on the setup menu whi
343. ercise 9 29 09 SLH TETR SPL 54 825 Le 52 0 01215 08 Step 6 store the current measurement readings press the ih Data key Select Store File and press the key This will store the measurement s data Data Files Store File H Recall 1 Step 7 To turn off the instrument press and hold the key until you are prompted to release it The instrument then turns off Quick Start 4 7 Viewing RTA Displays during a Measurement While taking measurements you can view the instrument s different displays This section provides examples of viewing the SSA instrument s four RTA displays which include e Live Leq e RTA Min Do the following to view the displays Step 1 Select the SLM amp RTA SSA instrument from the Setup menu and press RUN STOP S to begin tak ing a measurement as explained in the SLM amp RTA Measurements section found on page 4 3 Step 2 While the measurement is running press 9 View key The following screen appears If you select the RTA Live item with the D arrow key instead of the Q Check key you will be given the View SLI option to view the display in Any Pata graphical or Tabular mode RTA Intervals L3 Time History Step 3 Use the and W arrow keys to highlight the RTA item and press the Check Y key to select the RTA displays A screen similar to the
344. erentiates between daytime evening and nighttime noise exposure The equation for it is 0700 1900 2200 2400 1 L 10 10 Lj 10 L 5 10 L 10 10 Lien 100810 24 gt 10 10 10 10 0000 0700 1900 2200 The continuous equivalent sound level is generally calculated on an hourly basis and 1s shown in the equation as L The levels for the hourly periods from midnight to 7 a m have 10 added to them to represent less tolerance for noise during sleeping hours The same occurs from 10 p m to D 2 824 Reference Manual 9 29 09 Criterion Duration T Criterion Sound Exposure CSE Criterion Sound Level L Daily Personal Noise Exposure 1 Day Night Average Sound Level DNL Lan midnight The levels for the hourly periods between 7 p m and 10 p m have 5 added to them to represent a lessened tolerance for noise during evening activities They are energy summed and converted to an average noise exposure rating It is the time required for a constant sound level equal to the Criterion Level to produce a Noise Dose of 100 Criterion Duration is typically 8 hours Example If the Criterion Level 90 dB and the Criterion Duration is 8 hours then a sound level of 90 dB for 8 hours will produce a 100 Noise Dose See Noise Dose Standard ANSI 12 19 The product of the Criterion Duration and the mean square sound pressure associated with the Criterion Sound Level when adjusted for the Exchange Rat
345. ering Settings on page 7 23 9 29 09 For the SSA and Logging instrument the control settings are also accessed through the Edit Settings menu except that the last selectable menu item is Advanced Using the arrow keys highlight the Controls item then select it using the arrow key or the Y Check key Advanced Controls art Hind Tach Define Rep or Using the W arrow keys highlight the Controls item then select it using the D arrow key or the Check key Whether for the ISM SSA or LOG instrument the Controls menu will be as shown below Contrala The following is the menu layout for the control settings Menu Items Available Settings Options AC DC Output AC 1 2 AC DC AC DC 2 1 Logic In Mode None Pause Toggle Level Alarm Using ID Setting Files 7 11 NOTE Menu items Logic In Mode through Logic Out 2 Timer are system settings that are not stored or saved with an ID even though they appear in the SETUP menu NOTE The Logic out 2 uses the Heater output line if set to something other than off AC DC Output Settings SSA LOG ISM Logic Input Setting SSA LOG ISM The SSA instrument can access the Logic input Mode setting through either the Check or the Setup menus 7 12 Logic Out Off RMS Peak R P Intv PH R PH I A R I A P I A R PH A R S Excd Lo
346. ernal power status battery type and internal temperature Communication Baud Rate 300 115 K Lists command characters received and Serial Address data characters sent by the instrument Also Flow Control shows the current standby timer status The Modem serial port and display are turned off when Modem Mode the timer reaches 0 Dial Out Mode Phone Monitor Number Modem Init 9 29 09 Front Panel Keys Functions and Menus 3 19 About To access information about the System 824 use the 43 or W key to select About from the Tools menu then press the key The following screen appears Internal firmware revision number and date Instrument model number Instrument serial number Serial Humber Internal SLM firmware revision number and date About a QD Svetem 824 3 661 BHelanrzBB 3LH 3 528 Sh Jan2h4l RRSONeDRUTS IM The revision number indicated by REV is changed when firmware code change is made The revision number indicated SLM is changed only when a firmware code modification is made that affects the accuracy of any SLM measurement data and is used as an indicator to those who use third party verification NIST or PTB etc of instrument performance that testing should be performed About Settings edit mode can also be edited by pressing the V key from the About display scree
347. es it easy to measure room criteria NCB and RC using the RTA in 1 1 octave bandwidth The setup is configured to take data for 10 seconds at each location in a room Each measurement is automatically stored in the Autostore ByTime history ROOMS RTA is configured in the following way 824 Reference Manual 9 29 09 e Bandwidth 1 1 octave Detector Linear Linear Detector Time 00 1000 seconds e Autostore Yes ByTime No Triggering ON Trigger Mode Now End Mode Time End Time 10 0000 seconds End Then Stop Display Views This next section will explain the various displays available under the View key Once a measurement has been taken the 824 allows you to view the results and manipulate the data RTA Views The RTA Display Views are accessed through the View key To select the RTA Display Views press the View key The following menu will appear Spatial Ava 9 29 09 RTA optional 11 19 Now press the D right arrow key to bring up the View RTA display view menu Use the up and W down arrow keys to highlight the desired display The RTA display view menu offers 5 choices Live Leq Max Min and Times Use the check key to select the Live display Live If the sample time is greater than The RTA Live display shows the live spectrum and is the 0 25 seconds a display spectrum is current sampled data with a sample time based upon the generated and displayed to
348. ese eti ae re RE e a e SER ees 7 30 Sung e M M ates 7 25 BH RR ERE El Cao ea ie E ERR T RIPE cerro ied 7 26 VIEWS dan Aces bes Mec atu motae At NEA 5 69 Wind Direction Units ee eC E e HER RR T EUR 7 28 wand display eye ette ete teu E Eten e t eed e ERN E e ERE dS 5 61 wind exceedance level 5 ten RO ERU EHE RO elit 7 29 wind hysteresis ee ee RE UC re E Ue Fee oed edet 7 29 Wind pause enable sien ate Oe e ADR e E EN e eU e 7 30 WLC UIS AA tee emn mete bett panic east M oe manatee Macs it E C In 7 28 windy threshold 3 ema eR aem RR 7 29 Wi ndows printet Jide tetiiea ith oa nte deed dne 10 30 Windy Percent MICE 5 62 Windy Threshold pM LEE TERN 7 29 Write enable 3 2 dte 3 17 protect rosae re e te Te UR Ee ere rnt UR 3 17 Write protected l D A iain Rd ree ee ERU RO V EUR EE aes 4 16 Model 831 Technical Reference Manual Index 1v xxiil 1V XXiV Index Model 831 Technical Reference Manual Total Customer Satisfaction Guaranteed ARSON DAVIS 3425 Walden Avenue Depew NY USA 14043 Phone 716 926 8243 Toll Free 888 258 3222 A PCB PIEZOTRONICS DIV LarsonDavis com FAX 716 926 8215
349. et This is the time over which the current TWA is averaged The Exposure View has three displays which can be accessed by simply selecting Exposure with the Y Check key from within the main View menu then cycling through the views with the D and 4 arrow keys until the desired display appears System 824 Views 5 31 Exposure Display a The Exposure a display consists of seven major components Display label Dose Projected dose Time Weighted Average Sound Exposure Level Elapsed Time The Exposure a display is shown below Display label gt ISLAH Expazure a a Dose inze 2 0 Z Projected Dose 9 Proj Dose 2999997 Time weighted average eq 52 dBA Sound exposure level 34E SEL 20 6 dBA Elapsed Time w 12 14 4 The following explains each of the display s components Display label This shows the current display for example SLM Dose By definition a person receives 100 dose when exposed to a noise having a TWA equal to the selected criterion level for a time equal to the criterion time usually eight hours This corresponds to the maximum safe noise exposure Exposures at higher levels will result in a 10096 dose in less time or if exposure continues the exposure will exceed 100 dose Projected dose Projected dose is the dose that will occur i
350. et is 45 41dB The Linear Scale is 26dB for a 50mV g accelerometer The FFT displays a level of 121 7dB and 20 17g linear value 1 121 7dBTake the dB reading 2 121 7 45 41 167 11dBSubtract calibration offset 12 18 824 Reference Manual 9 29 09 9 29 09 3 167 11 167 0 11dBVsubtract 167dB 180 13 dB volts 4 0 11 26 26 11dBgAdd the Linear Scale setting 5 26 11 20 1 3055divide by 20 6 10 1 3055 20 21gtake 10 to this power result will be close to the FFT display The difference 40 296 between the 824 display and this calculation are primarily due to the precision of math done in the 824 versus precision of the math functions in the calculator Method 2 Take any FFT display reading that shows a dB and a linear level directly from the 824 display Calculate the linear reference level what linear level gives OdB using this formula R L 10 D 20 where R is the linear reference level for the current calibration settings of the measurement where L is the linear level displayed i e g or m s and where D is the decibel level displayed Here s an example I have an 824 connected to a signal generator supplying 0 5 volts RMS the Linear Units setting is g and the Linear Scale setting is 26 00 dB I run the 824 FFT for a while and press stop the display now shows a dB level of 121 7dB and a linear level of 50 87 milli g R L 10 D 20 05087 10 121 7dB 20 R 05087g 10 6 085
351. eved with the Query Q command The syntax for the query command is Q uery setting number options where setting number is the number of the desired setting and options is a number to select the appearance of the response Brackets indicate optional characters or operands lt cr gt carriage return lt If gt line feed space Syntax Response Q uery item_number flag Depends on flag Option flags elicit the following responses Flag Response none Current setting 1 Setting name and current setting 2 Current setting including spaces in brackets or parentheses 3 Setting name and current setting including spaces in brackets or parentheses 32 Option number for option setting 9 29 09 A 31 Flag values may be added together for desired combinations Example Response 1 074 No 2 074 1 Excd History Enable No 3 074 2 No 4 074 32 0 5 074 3 Excd History Enable _ No A 32 824 Reference Manual 9 29 09 Responses are denoted by x if Yes No or n if numerical Ln Query Commands SSA Commands Instru Description Comments ment Type Q 63 SSA Ln 1 Percent nn nn Q 64 SSA Ln 2 Percent nn nn Q 65 SSA Ln 3 Percent nn nn Q 66 SSA Ln 4 Percent nn nn Q67 SSA Ln 5 Percent nn nn Q 68 SSA Ln 6 Percent nn nn Q 139 SSA Enable Lns No Yes Q 224 SSA Start Level nn
352. evel at the frequency selected 824 Reference Manual 9 29 09 Use the right D and left 4 arrow Selected frequency Level shown at this frequency keys to change the frequency band Elapsed time Shows the elapsed run time accumulated since the last overall reset Use an Overall reset to reset Ln graph Graph of Ln for each frequency at the per overall data centage level displayed Logging SLM Specific Views The System 824 provides a number of different displays for the Logging SLM LOG instrument Understanding these displays allows you to take full advantage of this instrument All of these views can be accessed by pressing the View key when using the Logging SLM LOG instrument Additionally the W arrow keys can be used to cycle through an associated group of views There are three sets of these grouped views Any Data including Any Level Any Impl and Any Time Current SLM Overall SLM Exposure Ln Centiles and Stats Metrics PassBy and Wind Tach The Logging SLM LOG views are The following briefly describes the main views available in available when the Logging SLM is the Logging SLM LOG instrument the active setup These views can be accessed by pressing the view key Menu Items Purpose SLM SLM data with graphic display of Time History Any Data Tabular display of SLM data Current Maintains an accumulation of data that SLM may be rese
353. ey or the Y Check key to select it Using the and W arrow keys highlight the Advanced item then select it using the arrow key or the Y Check key The following screen appears Advanced Controls Hind Tach Rep DEUS Using the and W arrow keys highlight the Define Report item then select it using the arrow key or Check key The following screen appears Pr int Use the and 5 arrow keys to scroll through the available report settings Use the V Check key to select and change the options for each type of report 824 Reference Manual 9 29 09 For your report to print properly your printer must be connected as described in Connecting the 824 to a Serial Printer on page 8 1 configured as described in Printing Reports on page 6 2 NOTE Make sure you save your Instru ment ID before you change to a different Instrument ID otherwise all your newly defined tailored print settings will be lost Step 5 Press the C Print key to bring up the Print menu Step 6 Using and W arrow keys highlight the Tailored item then select it using the arrow key or the Y Check key and your Tailored report will begin printing Using the Recall Format SSA and LOG instruments only 9 29 09 The Recall Format menu allows you to customize the Sum mary report or the Tailored report and gives you two more customized repo
354. ey to toggle the data gathering mode of the instrument from stop to run or from run to stop The mode of the instrument is indicated on the display in the upper right hand corner by a running man symbol if the 824 Reference Manual 9 29 09 NOTE The Indicator Box in the upper right hand corner of the display will be solid if data is present or open if no data has been taken Reset Key instrument is running or a box symbol if the instrument is stopped Repeatedly pressing the 8 RUN STOP key after beginning a measurement will stop then restart the measurement with out resetting the data buffer As a result the time will con tinue to increase for the overall measurement The SSA ISM and LOG instruments within the System 824 contain two independent data buffers that can separately accumulate data In essence the instrument becomes two sound level meters in one The data in the primary buffer is referred to as the overall measurement while data in the secondary buffer is referred to as the current measurement 9 29 09 The RESET key allows you to clear the data of the cur rent measurement If you are using the simple sound level meter SLM instru ment and wish to reset the data simply press the RESET key This will reset all the data including the accumulated measurement values such as Leg For the other instrument types the System 824 gives addi tional flexibility when resetting the dat
355. f current noise levels continue for the entire criterion time 5 32 824 Reference Manual 9 29 09 Exposure b Display Time weighted average This display shows the Time Weighted Average TWA measured in dB Sound exposure level This display shows the Sound Exposure Level SEL measured in dB Elapsed time The timer display shows the elapsed run time accumulated since the last overall reset This is the time over which the overall TWA is averaged The Exposure b display consists of five major components Display label Sound exposure Sound exposure level Time weighted average Elapsed Time The Exposure b display is shown below Sound exposure level Display label SLM Exposure b Sound exposure amp E 0 00 Pack Elasped Time Time weighted average i4E SEL 65 8 dBA 1 42 4 dBA gt 0 81 51 4 Takt3 and Takt5 are available options if Takt functionality has been enabled See the Menu Item About on page 3 16 9 29 09 The following explains each of the display s components Display label Shows the current display for example SLM Exposure b Sound exposure Sound Exposure E in Pascal squared hours The Sound Exposure E is a function of the Leq and the elapsed time of the overall measurement System 824 Views 5 33 Time weight average This display shows the Time Weighted Average TWA measured
356. f one were using an SSA instrument with 20dB of gain the AC output would also have 20 dB of gain from the input The DC output voltage is proportional to the SPL specified approximately 0 25 dB in the by the weighting setting according to this formula PRM902 preamplifier SPL Vout 0 0275 StartLevel StartLevel is a setting on the Ln settings menu DC out has a range of 120 dB The output signals will vary based on which instrument type is used For LOG and ISM instruments the following table defines the output signals LOG and ISM Instrument AC and DC Output Settings 824 Menu 3 5mm Connector Tip Black 3 5mm Connector Ring red 1 AC 2 FLAT AC out FLAT AC out with 30dB gain AC 1 DC FLAT AC out Weighted DC out 2 DC FLAT AC out with 30 dB gain Weighted DC out AC 2 AC 1 FLAT AC out with 30 dB gain FLAT AC out For SSA instruments the following table defines the output signals output amplitude based on input Gain setting SSA Instrument AC and DC Output Settings 824 Menu 3 5mm Connector Tip Black 3 5mm Connector Ring red AC 1 2 FLAT AC out CWT AC out AC 1 DC FLAT AC out Weighted DC out AC 2 DC CWT AC out Weighted DC out AC 2 AC 1 CWT AC out FLAT AC out 6 6 824 Reference Manual 9 29 09 The DC output is generated digitally from the SPL but is slower than the SLOW or FAST detector response with an exponential time constant of approximately
357. f the SLM function is 80 dBA sufficient for most applications In operation the instrument measures four sets of frequency spectra the running instantaneous spectrum the Leq spectrum the spectrum associated with the maximum SPL level that occurred during the measurement and the minimum bin by bin spectrum It also gives you a time history record and Ln centiles The time history record stores up to 38 parameters of your choice including RTA Leq RTA Max or RTA Min which is determined by the Time History setup under the settings menu By using a 24 bit DSP processor the digital filters of the System 824 meets the specifications of IEC 61260 Class 1 and ANSI S1 11 1986 Type 1 D over a linearity range exceeding 80dB The dynamic range of the analysis function from noise floor to overload is 85 dB typical Eight ranges are available providing gain to 50 dB and attenuation to 20 dB in 10 dB steps The following presents the Measuring Ranges available for SPL Peak and 1 3 Octave Filter measurements for the SSA instrument 0dB Gain 20db Gain 30dB Gain 40dB Gain 50dB Gain Start End Range AW 20 78 58 Cw 20 78 58 FLT 40 78 38 16 0 23 78 55 31 5 1 23 78 55 63 0 0 18 78 60 125 2 8 78 70 250 3 8 78 70 500 4 8 78 70 1000 2 8 78 70 2000 6 8 78 70 4000 7 8 78 70 8000 7 13 78 65 NF is noise floor Start start of linearity range 6 4 A weighting C weighti
358. fails Without AC power or batteries installed memory loss will occur 1 18 The System 824 can be powered using a 3 6 V NiMH battery pack individual alkaline or NiMH cells or an AC power supply adapter For specifications on operating time under battery power see Battery Operating Time full capacity continuous operation reference environmental conditions individual cells may vary in performance on page C 6 Below we will discuss how to install and use each To use a NiMH battery pack 010 with the System 824 unscrew the battery cover at the back of the System 824 by hand or using a flat blade screwdriver If individual cell batteries were previously used remove the Terminal Assembly Figure 1 8 Insert the battery pack so that the positive terminal is oriented down and to the right as shown in Figure 1 7 Positive Terminal Figure 1 7 Battery compartment and cover with NiMH battery pack installed Note location of positive terminal 824 Reference Manual 9 29 09 Using Alkaline Batteries or Individual NiMH rechargable cells Use Duracell MN 1500 1 5 volt 2 850 mAH alkaline battery or equivalent You may also use the Duracell Ultra Energizer Titanium next generation batteries which may provide up to 40 more run time Note It is important to set the battery type to NiMH if individual NiMH cells are being used to power the instrument otherwise there will not
359. flexible acquisition Autostores up to 400 spectra per second one spectrum every 0 0025 seconds Has both exponential and linear detectors Direct printing of calculated RT60 for every 1 1 octave or 1 3 octave band RTA optional 11 1 Settings Menu ROOMS RTA is setup to be a 1 1 octave analyzer that takes 10 second measurements for NCB and RC analysis RT60 A RTA is set to be a 1 3 octave analyzer for the measurement of RT 60 with the room being excited with pink noise RT60 B RTA is set to be a 1 3 octave analyzer for the measurement of RT 60 with the room being excited with impulsive noise such as from a pistol balloon pop etc Minimum RT 60 Value The Settings menu for the RTA instrument is accessed from the SETUP key There are three permanent RTA instrument definitions ID available ROOMS RTA RT60 A RTA and RT60 B RTA To select an RTA instrument press the SETUP key scroll down to RTA and press the Y check key The RTA Live view will now be displayed Press the 7 SETUP key again to return to the SETUP menu At the top of the Setup menu Edit Settings will be highlighted Press the Y check key to edit the RTA settings menu See chapter 5 of this Manual for more details on selecting instrument IDs The minimum RT 60 which can be measured also referred to as the Residual RT 60 is a function of 1 3 octave response time as shown in the following graph
360. following appears 4 8 824 Reference Manual 9 29 09 The RTA Live screen shows a graphical display of the sound readings over a range of frequencies The SPL for the selected frequency is displayed in the upper left corner The frequency as selected by the vertical cursor is displayed in the lower left corner As the frequency is changed the cursor vertical bar will move accordingly across the graphical display highlighting the corresponding graphical sound reading Additionally the digital frequency display will also change as will the digital readout of the sound measurement for the newly selected frequency The RTA Leq view shows a graphical display of average sound exposure for the measurement time The LEQ for the selected frequency is displayed in the upper left corner The selected frequency is displayed in the lower left corner When the cursor is moved to the far right side the broadband Leq is shown numerically and the cursor is no longer displayed as shown here This is the minimum level obtained for each frequency since the last current reset 9 29 09 Step 4 Step 5 Step 6 Step 7 SLA R TA Live 5 Use the D and 4 arrow keys to change the selected frequency As the selected frequency 1s changed the SPL for that frequency will be displayed in the upper left corner Additionally the cursor bar will move along the graph to the position that corresponds to the SPL gra
361. free field microphone The graphs below show the response of the free field microphones before and after the random incidence correction has been added 824 Reference Manual 9 29 09 Graph 1 The 824 in normal range with the 2540 free field microphone showing the uncorrected random response LD Model 824 Serial 0132 Normalized to 1000 00Hz 8 O xy with Standard Deviation Tested 06 30 99 15 36 44 by Leroy Harbaugh Note PRM902 SN 0224 2540 SN 4172 Reference Mic Model 4133 Serial Number 1424039 Tested 06 30 99 05 55 15 Lo bM Type 1 limits Graph 2 The 824 in normal range with the 2540 free field microphone showing the corrected random response LD Model 824 Serial 0132 Normalized to l1000 00Hz 8 0 xy with Standard Deviation Tested 06 30 99 15 36 44 by Leroy Harbaugh Note PRHS902 SN 0224 2540 SN 4172 Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 06 30 99 05 55 15 4 0 Type 1 limits 9 29 09 C 25 Graph 3 The 824 in normal range with the 377B41 free field microphone showing the uncorrected random response LD Model 824 Serial 0132 Normalized to 1000 00Hz 8 0 xy with Standard Deviation Tested 07 06 99 10 26 22 by Leroy Harbaugh Note PRMS02 SN 0224 2541 SN 5636 Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 06 30 99 0
362. g the readings and storing data in the System 824 Introduction 1 1 Chapter 5 System 824 Instrument Modes Provides descriptions of the System 824 s standard instrument ID s Chapter 6 System 824 Views Gives you a detailed description of the different display views available and how to access them Chapter 7 Using ID Setting Files Describes how to recall customize and save IDs Chapter 8 Printing a Report Describes how to print a report of the data collected with the System 824 e Chapter 9 Performing a Sound Level Measurement Walks the user through the steps necessary to obtain a sound level measurement whose accuracy will be optimal for the measurement conditions Chapter 10 Using the 824 Utility Software Describes how to connect the 824 to a computer in order to download translate and export data Chapter 11 RTA Optional Explains how the RTA high speed data gathering option enables you to perform architectural acoustics impulse event analysis and passby event analysis Chapter 12 FFT Optional Describes the features and functions of the fast fourier analysis option Chapter 13 AUD Optional Explains how the AUD option can be used to manually test an audiometer by measuring level frequency THD pulse crosstalk frequency modulation narrow band broad band and speech noise Appendices Appendix A Integrated Level Calculations Provides informat
363. gasurement at end of each Interval To store an interval histogram for the SSA instrument select SLM amp RTA from the measurement list click on the Interval tab and check the box by Store complete Histogram NOTE Storing interval or daily histograms for the LOG instrument is done in a similar manner 824 Reference Manual 9 29 09 These settings only affect how the data is displayed and not how they are stored Histogram Report Options Overall Interval Daily Resolution fi dB bd H 1dB m Low Limit s 70 dB ro dB 6 dB High Limit 5 gg 120 dB dB 5 dB Histogram Options Window The histogram options window allows more flexibility in viewing the histograms Here you can set the parameters to fit your particular needs To access the histogram options window go under the View menu item and select Histogram Options SPL Peak Uw Peak SPL When viewing the histogram data the changes made in this window will be immediately displayed The daily data is only available to the LOG instrument Note High limit will be adjusted downward if necessary to maintain even steps The Overall area allows you to set the viewing parameters for the overall SPL Peak and Unweighted Peak histograms The Interval Daily column sets the parameters for display ing the SPL histogram for the interval period for either the SSA or LOG instruments
364. ght Set Reference and press the check key once more The reference can also be set to an absolute level using the Reference Lvl setting on the check menu This zero level may be set at the 70dB HL point as a reference Once the reference has been set the level is shown relative to the reference level as shown below inearity FFT X THD n 0 02 T Level Reference h 2dp 7 75 208 This display has a manual and an automatic filter lock feature to lock to the desired filter frequency when going to low amplitudes where other noise signals ambient noises or vibrations present in the environment may be higher than the signal being output by the audiometer The right and left arrow keys control the lock mode Press right once to AUD Optional 13 15 Manual Lock Automatic Lock 13 16 manually lock to the current frequency a lock icon will appear as shown below Lock Icon Linearity RTA amp 1 3 Level Reference 7 84 77 8 E Press the left arrow key once to activate the automatic lock mode a diamond shaped icon will appear The lock mode will step in sequence from unlocked to manual locked to automatic and back to unlock with the right arrow The left arrow will sequence through the modes in the reverse order For manual operation select unlock while at a high amplitude 70dB HL or above where the highest amplitude filter can be detected easily When the correct frequency is dis
365. gic Out Time 0 255 sec Logic Out 2 Same settings as Logic Out Logic Out 2 0 255 sec Timer Heater On Yes No E A Cal Tone Yes No The AC DC Output on the 824 allows the user to select what type of signal will be sent out the 3 5mm connector at the base of the instrument See the section AC DC Output on page 6 5 for more details The Logic Input sets the functionality of the logic input pin on the control connector pin 3 This pin is intended to be connected to an external switching device possibly a push button switch The external switching device will either connect the pin to 5 V pin 6 or unconnected This signal may also be supplied from another device that can supply a 0 824 Reference Manual 9 29 09 Caution The Level setting overrides the RUN STOP key and I O Run Stop function commands Logic Output Setting SSA LOG ISM 9 29 09 to 5 volt logic signal input load impedance is 100K ohms The resulting logical state high or low will determine what occurs inside the instrument as a function of this Logic Input setting Accordingly the setting provides the following five options None The state of the logic input pin has no effect Pause Whenever the logic input is connected to 5V e g when a push button switch makes con tact the instrument pauses when in the run mode Toggle Each time the logic input is connected to 5 V e g switch makes contact t
366. ginal value It can be expressed Frequency Band Pass Filter Frequency Filter Weighted D 10 in cycles per second and the value has the unit symbol Hz Hertz added and the letter f is used for a universal descriptor It can also be expressed in radians per second which has no symbol and the greek letter c is used for a universal descriptor The two expressions are related through the expression o 2TIf The part of certain sound level meters that divides the frequency spectrum on the sound or vibration into a part that is unchanged and a part that is filtered out It can be composed of one or more of the following types Low Pass A frequency filter that permits signals to pass through that have frequencies below a certain fixed frequency called a cutoff frequency It is used to discriminate against higher frequencies High Pass A frequency filter that permits signals to pass through that have frequencies above a certain fixed frequency called a cutoff frequency It is used to discriminate against lower frequencies Bandpass A frequency filter that permits signals to pass through that have frequencies above a certain fixed frequency called a lower cutoff frequency and below a certain fixed frequency called an upper cutoff frequency The difference between the two cutoff frequencies is called the bandwidth It is used to discriminate against both lower and higher frequencies so it passes only a band of frequencies Octave
367. ging SLM Triggering Settings LOG and SSA Ln Settings 824 Reference Manual 9 29 09 Example Common SLM Settings Title Setting SSA LOG ISM To change the Title use the D and keys to select each character Use the and W keys to replace the selected letter Pressing the Reset key clears all characters from the cursor to the end of the field Detector Setting SSA LOG ISM The 824 measures all three frequency weightings with three detectors simultaneously and all nine of these levels can be viewed 9 29 09 LOG and SSA Time History Settings Logging SLM Interval Settings Logging SLM Exceedance History Settings Logging SLM Daily History Settings Logging SLM Define Report Settings In the following sections headings for each setting or display mode will identify in parentheses the particular System 824 instruments to which they pertain as shown in the following example Title Setting SSA LOG ISM The SSA ISM and LOG instrument types include standard SLM functions This section covers the available SLM settings for these instruments Use the Title setting to create a title or header for printed reports This title header will be placed at the top of each report you print Detector selects the detector rate of the instrument s RMS detector This setting provides the following three options Slow An exponential average with a one second time constant F
368. ging facilities allow user selected spectra to be averaged on an equal weighting basis It is often used to average the spectra that were measured at various locations around a noise source or across the length of a wall or partition The resulting average is displayed and can be stored into a history for later viewing The Spatial Avg Display Views are accessed through the View key To select the Spatial Avg Display Views press the View key and highlight Spatial Avg The following menu will appear 9 29 09 RTA optional 11 35 Spatial 0 Now press the D right arrow key to bring up the View Avg display view menu z Spatial 0 The View Avg display view menu offers 2 choices Spatial Avg and Avg History Use the check key to select the Spatial Avg display Spatial Avg The Spatial Avg display shows the spectra which have been currently averaged Display label gt Spatial Ava 120 ra ee wa EU OR an 100 ee ey Bandwidth 1 1 or 1 3 oct ___ pi gn Selected filter frequency p id 2y Spatial averaged sample count gt 34 Annunciator or note Test 2 Spatial averaged spectrum 40 Ege NOTE If the right digit of the annunciator is numeric then it will auto increment with each spatial average store operation from the check menu 11 36 824 Reference Manual 9 29 09 Any display which shows a spect
369. h backlight OFF SSA Running with backlight ON Power Charging 2 Charging NOTE Current milliamperes draw varies with voltage while the power con sumed watts is constant Question 3 Answer 9 29 09 What is the minimum RT 60 that can be measured with the 824 RTA The graph on the next page shows the minimum RT 60 that can be measured This is also called the Residual RT 60 and is a function of the 1 3 octave filter response times Residual RT 60 Hz 9 AQ A08 99 0099 0099 N 4 908 0400 o 5 oo Question 4 What does Start Level do as found in the SSA and LOG instruments Ln settings menu Answer The Start Level setting indicates where the histogram G 4 table from which Ln data is calculated begins The table only has a range of 128 dB yet the 824 can measure over a 150 dB range when the Gain or Range settings are considered The default value for Start Level is 15 dB and provides Ln data and SPL histograms from 15 dB up to 142 9 dB Start Level is also used with the main weighted Leq in the Time History Due to internal data encoding the range is limited to 127 dB and uses Start Level to determine the desired measurement range Since the time history is a data logging function and the likelihood of changing the Gain or Range set
370. he SSA instrument the logic output is asserted when it reaches this level See the section Common Control Settings on page 7 10 for more details SPL Excd Lvl 2 LOG SSA 9 29 09 Trigger levels can be set as follows two for the SPL RMS value and one each for Peak I and Peak II These levels are used with the LOG instrument to count the number of exceedances during the measurement period and display that number in the Stats a and Stats b displays They also define the triggering of noise events or exceedances when using the Logging SLM Mode The following is a table of the Triggering Menu settings Each setting is then described in greater detail Menu Items Available Settings Options SPL Excd Lvl 1 0 to 255 dB SPL Excd Lvl 2 0 to 255 dB Pk 1 Exed Lvl 0 to 255 dB Pk 2 Excd Lvl 0 to 255 dB Hysteresis 0 to 9 dB SPL Excd Lvl 1 sets the SPL trigger level that exceedance records are triggered from LOG only You can also view a count of the SPL events on the Stats a display This count is associated with the overall measurement data and is reset when the overall measurement is reset This setting can take on any value within the following range 0 to 255 dB The SPL Excd Lvl 2 sets a second trigger level When the SPL exceeds the level set by this setting a corresponding count is incremented once You can view this count on the Stats a display This count is associated with the overall measu
371. he Settings menu to the SLM sub menu and from the SLM sub menu to the Selections menu the item highlighted was not the first in the list Observe that when Q was pressed to accept the selection of FLT for the frequency weighting upon returning to the Weighting sub menu the 2nd item was highlighted just as it had been previous to entering the Selection menu using Continuing the example press 4 to exit from the SLM sub menu to the Settings menu and note that the 2nd item 18 highlighted just as it had been earlier when D was used to move from the Settings menu to the SLM menu Essentially when the 4 D key is used to move from a Menu Sub menu or Selection menu a pointer in the menu is set to the item which is highlighted at that time If in the process of continuing with the editing process a Menu is accessed once again using the 4 keys the item highlighted is determined by that pointer Continuing the example use 4 to exit completely from the Setup menu Enter the Setup menu again by pressing O and use three consecutive presses of D to display the Settings menu SLM sub menu and Selection menu In each case the highlighted item is as it had been when previously exiting from that Menu To the experienced user this can be a valuable feature Suppose for example one wished to use the Setup menu to quickly switch between choices of frequency weightings Using the 4 D keys alone one could access the desire
372. he currently displayed interval Lpeak II Reading The Lpeak II Reading shows the LPeak II reading for the currently displayed interval Interval Duration The Interval Duration shows the length of time of the currently displayed interval The Interval d display consists of six major components Display label Interval Number SPL Exceedances Peak I Exceedances e Peak Exceedances Overloads The Interval d display is shown below for the LOG and SSA instruments Display label Interval d SPL Exceedances 3d9 SFL gt 115 B times Interval Number Peak I Exceedances Paak I gt 144 Btimes Peak II Exceedances M Peak II 146 times Overloads yer loaded times B 4 5 48 824 Reference Manual 9 29 09 Intervals e Display 9 29 09 The following explains each of the display s components Display label This shows the current display for example Interval d Interval Number The Interval Number display shows each measurement interval in the order that it occurred The Interval Number indicates the order of the displayed interval in relation to the other interval records SPL Exceedances SPL Exceedances shows how many times during this interval that the instrument s SPL Exceedance Level was surpassed Peak I Exceedances Peak I Exceedances shows how many times during this interval that the instrument
373. he cursor 824 Reference Manual 9 29 09 NOTE The linear units level is displayed in engineering exponential notation This notation expresses the exponent with a single character for nano 10 for micro 1076 for mili 10 a space for no exponent k for kilo 10 for mega 10 and G for giga 10 Frequently Asked Questions Concerning FFT What is the reference level for decibels dB levels in the FFT option of the 824 The decibel levels displayed by the FFT option of the 824 are the same as those for SPL in other instruments such as SSA or ISM and is 20 micro Pascal set during your microphone calibration process Now that may not mean much if you are viewing the output of an accelerometer rather than a microphone The linear units are available to view the output of the accelerometer but the dB level may be of use To calibrate the dB level to some usable value for acceleration requires the use of an accelerometer calibrator We use the PCB 394C06 Portable 1g Handheld Shaker Set the calibration level to something like 140dB and run through the calibration procedure Then the 824 FFT will read 140 dB when it is excited with 1g This provides a reference of 0 1 micro g also 1 micrometer per second squared How do get the DNA software to read FFT data in linear units 9 29 09 To get DNA to read FFT data in a linear unit such a g or m s the data must be
374. he instrument runs or stops The effect is the same as pressing the Run Stop key Level When the logic input is connected to 5 V e g switch makes contact the instrument runs When the logic input is disconnected from 5 V e g switch breaks contact the instrument stops Alarm When the logic input is connected to 5 V e g switch makes contact the instrument initi ates a dial out sequence This option is intended for use only with advanced remote monitoring applications where the instrument is paired with a modem The Logic Output 2 outputs are available selects the functionality of the logic output pin on the control connector pin 2 referenced to ground which is on pin 1 and the heater output pin 8 pulled to ground You can use these Logic Outputs to actuate external devices during certain events or combinations of events that occur in the instrument The option you select determines which types of events will trigger a logic output line Using ID Setting Files 7 13 NOTE In many of the options below notice the use of a shorthand identifier which includes the first letters of the various events along with the plus symbol The plus symbol indicates a logical OR function between events In other words if for a given option any one of the listed events occurs alone or in combination with another event the logic output will turn on The A D or A functions are for compatibility with systems tha
375. hted Sound Levels at Upper and Lower Limits of the Linear Operating Range The following table presents the nominal A weighted sound levels at the upper and lower limits of the linear operating ranges for each level range The starting point for testing the level linear errors of the reference range 15 114 dB 31 5 Hz 1 kHz 4 kHz 8 kHz 12 5 kHz SLM ISM Normal Range 63 dB to 128 dB 19 dB to 128 dB 18 dB to 128 dB 21 dB to 128 dB 26 dB to 128 dB Low Range 59 dB to 108 dB 18 dB to 108 dB 18 dB to 108 dB 19 dB to 108 dB 22 dB to 108 dB SLM amp RTA SSA 0 dB Gain 83 dB to 128 dB 43 dB to 128 dB 43 dB to 128 dB 47 dB to 128 dB 49 dB to 128 dB 10 dB Gain 73 dB to 118 dB 33 dB to 118 dB 32 dB to 118 dB 35 dB to 118 dB 39 dB to 118 dB 20 dB Gain 64 dB to 108 dB 24 dB to 108 dB 23 dB to 108 dB 25 dB to 108 dB 29 dB to 108 dB 30 dB Gain 58 dB to 98 dB 19 dB to 98 dB 18 dB to 98 dB 20 dB to 98 dB 23 dB to 98 dB 40 dB Gain 58 dB to 88 dB 18 dB to 88 dB 17 dB to 88 dB 19 dB to 88 dB 22 dB to 88 dB 50 dB Gain 58 dB to 76 dB 18 dB to 78 dB 17 dB to 78 dB 19 dB to 78 dB 22 dB to 78 dB Electrical Signal Input Device Inherent Noise 9 29 09 The electrical design of the input device to insert electrical signals into the preamplifier is a series 1
376. icated by each live display s graph scale The following selections are available 824 Reference Manual 9 29 09 NOTE If Gain is set to 10 or 20 dB and the microphone type is not condenser then the gain is set to 0 dB and the warning Setting Conflict is displayed Range Setting LOG ISM The Range setting is only available to the LOG and ISM instrument NOTE If Range is set to Low and the microphone type is not condenser then the range is set to Normal and the warning Setting Conflict is displayed High Range is not available for electret or direct transducer types see Transducer Setting below 9 29 09 20 10 0 10 20 30 40 50 Use the W keys to highlight the desired value of gain and press J Check key Range selects the measurement range you desire for the instrument This setting provides the following three options Normal The instrument s available dynamic range is positioned in the normal range which is typically 20dB to 130dB when using a Lar son Davis high sensitivity microphone Low The instrument s input circuitry provides an additional 20dB of gain which has the effect of moving the instrument s available dynamic range downward relative to the normal range The net effect is that you can measure lower level sounds effectively The degree of benefit varies depending upon the weighting or filter that you are using High The instrument s sens
377. icrophone 12 5 kHz Graph 16 824 in the YZ plane fitted with the 377 41 microphone 1 kHz WM LT AN v 25550 uM E 9 29 09 C 41 Graph 17 824 in the YZ plane fitted with the 377 41 microphone 2 kHz ACCES AH SE oe 2 STN 1 7 Ly 59 5 Graph 18 824 the YZ plane fitted with the 377 41 microphone 4 kHz as Nn SM x Es TRY C 42 824 Reference Manual 9 29 09 9 29 09 Graph 19 824 in the YZ plane fitted with the 2551 microphone 8 kHz CES 552 OSS c Graph 20 824 in the YZ plane fitted with the 377 41 microphone 12 5 kHz Graph 21 824 in the XY plane fitted with the 2551 microphone 1 kHz Larson Davis Model 2551 Serial 0099 Normalized to 1000 00Hz 8 0 xy Tested 03 02 01 16 31 06 by James Higley Note Prepolarized Microphone Reference Mic amp Model 4133 Serial Number 1424039 Tested 03 01 01 08 20 13 of 6 0 dB Graph 22 824 in the XY plane fitted with the 2551 microphone 2 kHz Larson Davis Model 2551 Serial f 0099 Normalized to 1000 00Hz 8 0 xy Tested 03 02 01 16 31 06 by James Higley Note Prepolarized Microphone Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 03 01 01 08 20 13 0 6 0 dB 10 0 14 0
378. ight No and press to make it the Active ID Step 4 Press to display the Setup menu with SLM amp RTA SSA unmodified as the Active ID Edit Settings SLM sl P Logging LOG SLH amp RTA Ji Accessing the Settings Menu to Initiate Editing or Modification As mentioned above the first item on the list highlighted is the Active ID The message Edit Settings along with the symbol gt to the right indicates that one should press in order to view or edit the Active ID In many cases the O Check key will accomplish the same result This will produce the Settings menu list as shown below Intervals Note that all of the items in this list with the exception of the first Title have the symbol gt to the right indicating a sub menu In order to illustrate the Settings menu structure please perform the following steps to set the SLM Weighting function 4 18 824 Reference Manual 9 29 09 9 29 09 Step 1 Use W to highlight SLM Detector CS low Heighting 1 Gain 80 Step 3 Use W to highlight Weighting note that the present selection is A Heighting CA Gain 80 L ud menu Gain 80 Step 5 Use W to highlight FLT Quick Start 4 19 Step 6 Press to select FLT as the new SLM Weighting CFL Gain 80 For the purpose of continuing with this examp
379. ime lt 50 uS Peak Detector Frequency Response Graph 824 Relative Frequency Response Flat 700000 0 AC DC Output LOG and ISM modes only 824 Menu 3 5mm Connector Tip 3 5 mm Connector Ring AC 1 AC 2 Flat AC output Flat AC output with 30dB gain AC 1 DC Flat AC output Weighted DC output AC 1 DC Flat AC output with 30 Weighted DC output dB gain AC 2 AC 1 Flat AC output with 30 Flat AC output dB gain NOTE In low range all AC outputs will provide an additional 20 dB of gain C 10 824 Reference Manual 9 29 09 9 29 09 RMS Measurement Range LOG and ISM modes only Electrical Low High Range Pulse Noise Floor Limit Limit Range A WT high 22 43 151 gt 108 gt 108 A WT normal lt 12 lt 23 131 gt 108 gt 108 A WT low lt 10 lt 20 111 gt 91 gt 91 C WT high lt 38 lt 48 151 gt 103 gt 103 C WT normal 18 28 131 gt 103 gt 103 C WT low lt 14 lt 25 111 gt 86 gt 86 FLAT high lt 40 lt 50 151 gt 101 gt 101 FLAT normal lt 20 lt 30 131 gt 101 gt 101 FLAT low lt 15 lt 25 111 gt 86 gt 86 NOTE Ranges are in dBSPL using a typical 377B41 microphone with sensitivity of 44 5 mV Pa and a 200V polarization voltage 2540 normal sensitivity microphone produces high limit values approximately 10 0 dB higher NOTE Ranges are in dBSPL using a typical 377B41 micropho
380. ime accumulated since the last overall reset 824 Reference Manual 9 29 09 NOTE Spectral Lns are measured for SSA instrument only If a display bandwidth of one octave is selected with the bandwidth setting these displays will indicate No Data Available 1 1 octave Ln graph Graph of Ln s from 1 to 99 1 being on the left 99 on the right There are two levels represented by each bar The highest of the two are graphed Spectral LNs To return to the Ln display menu press the View 9 key To view the Spectral Lns highlight Spectral and press the check Y key to view a tabular spectral display Spectral Spectrum tail Spectrum 20 Spectrum 30 This is a tabular display for each 1 3 octave frequency showing six Ln values for the selected frequency Below is an example of one of the displays shown for each frequency Display label 3 f Selected frequency gt 125 8Hz 4 67 LB zz 96 5 935 6 Percentile values amp levels ___ L33 3 50 0 1 88 5 83 5 L n n 6 33 8 The f indicates Ln of frequency P Use the right D and left 4 arrow keys to move to each 1 3 octave frequency 9 29 09 The following is a brief description of each of the components of this display Display label The Display label identifies the display which is the SSA Ln f display showing six Ln percent va
381. in Marker 5 Animal Hist Enable LOG SSA This setting provides the following two options No Time history storage is disabled Yes Time history storage is enabled 7 32 824 Reference Manual 9 29 09 Hist Period LOG SSA This setting is used in conjunction with the Period Units Setting below Period Units LOG SSA Example Hist Period sets the number of history period units that transpire between successive time history samples These samples continue either until the instrument is stopped or runs out of memory This setting can include any integer value in the following range 1 to 255 Period Units selects the type of units the instrument uses to calculate the time which transpires between successive time history storage operations To calculate the timer period the instrument multiplies the units selected in this setting by the number set in Hist Period setting see the previous Hist Period setting and the following example To measure 2 samples per second set Hist Period to 16 and Period Units to 1 32s 16 32 1 2 When Takt functionality is enabled the history period will be rounded to the nearest 5 second interval and a warning Setting Conflict will appear If the Period Units equal 1 32nd of a second then the period will be forced to a count of 160 5 seconds In the SSA instrument the shortest time history period is 1 8th of a second If the pe
382. in dB Sound exposure level Shows the Sound Exposure Level SEL measured in dB Elapsed time Shows the elapsed run time accumulated since the last overall reset This 1s the time over which the overall TWA is averaged If Takt functionality has been enabled the Exposure b display will look as shown below Display Label IH Exposure b Sound Exposure amp Ez 0 00 Takt3 gt Takt3 161 8 dBA Takt5 gt Takt 181 8 Timer gt 1 Exposure c Display The Exposure c display consists of four major components Display label e C Weighted TWA A Weighted TWA Cminus A TWA The Exposure c display is shown below 5 34 824 Reference Manual 9 29 09 Display label p gt ET Expazsure lnusz C Weighted TWA 9 1dB C A Weighted TWA gt 51 dB A C A Weighted TWA 9 dB C A This measurement is commonly used for assessing the effectiveness of hearing protection Ln Centiles Views The and W arrow keys can be used to cycle between the Current SLM Overall SLM Exposure Ln Centiles and Stats views from the Ln a display Ln a Display 9 29 09 The following explains each of the displays Display label Shows the current display for example SLM Exposure c C Weighted TWA This display shows the C weighted TWA Leq over the duration of the measurement A Weighted TWA This d
383. in frequency The second harmonic is found by doubling the fundamental frequency then finding the nearest bin frequency and summing its level with its side band levels The third harmonic is found by tripling the fundamental frequency then finding the nearest bin frequency and summing its level with its side band levels The fourth and higher harmonics are found by the process described above by summing the energy of these harmonics THD n is calculated by summing the energy of the fundamental bin with the five bins on each side then subtracting the energy sum of all the other levels For THD to be calculated the following criteria must be met The window must be in Hanning mode after an overall reset If not Available only in Hanning Window is shown The fundamental must be above the 4 bin or 10 Hz whichever is higher In the case where the fundamental frequency is near the 5 bin and it s skirt extends into some or all of the first four bins the fundamental energy sum calculation will include only the 3 and or 4 bins but not the 1 or 2 bin In any case the noise energy sum calculation will never include the first four bins The fundamental must be higher than any of the first four bins There must not be excessive DC or near DC levels THD n must be at least 10 dB below the fundamental level There must be an identifiable tone The fundamental frequency will be displayed whether there 1s an identifiable
384. in the main View menu then cycling through the views with the D and 4 arrow keys until the desired display appears The Wind a display consists of five major components Display label Sound Pressure Level e Windspeed Wind Direction Frequency of Windspeed Signal The Wind a display is shown below HPH Display label LJ tnd Windspeed lt q Sound Pressure Level B Ha Hz A Frequency 0 Wind Direction Compass a HE SFL c 9 29 09 System 824 Views 5 69 Wind b Display 5 70 The following explains each of the display s components Display label This shows the current display for example Wind a Sound Pressure Level This displays the instantaneous sound pressure level Windspeed This displays the instantaneous windspeed Wind Direction This displays the instantaneous wind direction using compass coordinate points or in degrees Frequency This displays the instantaneous frequency of the signal from the windspeed transducer This parameter is used primarily for troubleshooting The Wind b display consists of seven major components Display label Live Wind Speed and Direction Average Windspeed Maximum Windspeed and Direction Date Time of Maximum Windspeed Wind Exceedance Data Windy Threshold Data The Wind a display is shown below 824 Reference Manual 9 29 09 Display label LJ 3 ric b
385. ined ID registers cannot be changed or deleted and do not reduce the amount of data memory available They are to be used primarily as templates for new user defined IDs Important In order to not lose your customized settings in the event of memory loss or firmware upgrade follow these steps Deleting Stored Data Delete Last Function 824 Memory Structure 9 29 09 Front Panel Keys Functions and Menus Allocated ID s Determines the number of setup registers that are allocated in memory for storing IDs In essence this setting determines how much memory is allocated for stor ing instrument definitions Setting this to a higher value allows more IDs to be created but reduces the amount of memory available for data storage by 512 bytes per allocated ID Create EEPROM Backup Stores the most recently used SSA ISM and LOG IDs so that they may be recreated in the event of a memory loss 1 Alter the permanent IDs as desired and save your customized setting using a name of your choice 2 Enter the unit Name and other system settings in the TOOLS gt About menu 3 Bring your favorite ISM LOG and SSA ID to the top of the SETUP ID menu by selecting them one at a time Alter a permanent ID and save your customized setting using a name of your choice 4 Store these settings permanently using the TOOL gt Mem ory gt Create EEPROM Backup menu item Your settings will not become permanent Repeated whenever you updat
386. ing ID Setting Files 7 29 Wind Pause Enable Pulse Trigger Voltage Pulse Source dB Begin Y Hysteresis A Trigger Time Select Yes to enable the Wind Pause Function This will cause the System 824 to pause sampling of the input signal whenever the wind speed is above the Wind Exceedance Level Select No to disable this function Select 0 0 V for bipolar trigger signals which are essentially AC triggering occurs on the zero crossing Select 2 5 V for unipolar trigger signals such as those based upon 0 5 volt logic Generally the trigger signal for windspeed detection will be from an external transducer connected to the 9 pin connector labeled CONTROL In this case select Ext If Int is selected the signal connected to the System 824 input will be used to determine the Wind Tach level This setting will allow the measurement of the frequency of an acoustic signal LOG and SSA Time History Settings Time History Settings are available to both the Logging SLM LOG and SLM amp RTA SSA instruments The time history recording stores an Lgo and if desired one or more additional user selected measurements such as Lpk or Lmax Levels can be stored rapidly up to 32 samples per second with the LOG instrument and 8 samples per second with the SSA instrument Since this function continues storing data as long as the measurement is in progress the combination of a fast storage rate and a l
387. ings so you can modify the items in the Controls menu This section will present the Check menu screens that display when pressing V Check key from within the System 824 SSA instrument definition The following Check menu is accessible from the Data screen Press the Check key and the following appears Using ID Setting Files 7 65 Following is a chart of the check menu with a description of each menu item Menu Items Purpose Mark Puts a marker in the time history Settings Modifies the SLM settings for the selected instrument RTA Check Menu The following Check menus are accessible from the RTA Live RTA Leq RTA Max and RTA Min views Spectrum Gett ings gt Bandwidth L14 31 SLH PRT SLAARTA n Following is a chart of the check menu with a description of each menu item Menu Items Tabular Spectrum Purpose Enables switching between spectrum graphical view and Tabular view Settings Modifies the SLM settings for the selected instrument 7 66 824 Reference Manual 9 29 09 Graph Changes the scaling of instrument s SLM history graph Bandwidth Selects either 1 1 1 3 octave filters Intervals Check Menu The intervals displays have three different check menus depending upon which display you are viewing When viewing the displays Interval a through Interval e the fo
388. ints SPL histogram and overall Spectral LN report Lowest Level 045 Selects the lowest SPL histogram level to be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 5 0 Selects the SPL histogram resolution Pk 1 Histogram No You can customize the Peak Histogram report by choosing the long or short report Lowest Level 110 Selects the lowest Peak histogram level to be printed Highest Level 160 Selects the highest Peak histogram level to be printed Resolution 5 0 Selects the Peak1 histogram resolution Pk 2 Histogram No You can customize the Peak2 Histogram report by choosing the long or short report Lowest Level 070 Selects the lowest Peak2 histogram level to be printed 9 29 09 Printing a Report 8 9 Summary Report Template SSA instrument Histograms Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 5 0 Selects the Peak2 histogram resolution Summary Report Template LOG instrument Report Settings Lower Level Report Settings Description Unformatted No A dump of all Read Query and Interval remote commands Multiple values are comma delimited Data Report Yes This shows general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Log Report Yes The run stop log and with the date and time of each run stop
389. io scd TRE Ode ee 9 7 Selecting the SEM Display na ei he eT Ie HERES 9 9 Selecting the Measurement Range eene 9 9 ISM and EOG Modes iiit e peo ee Ino pee ERE 9 9 Selecting the Range 1 9 10 SSA e rere ER DUE e DP UE PERS 9 10 Performing a Measurement petere ete NECS 9 11 Averaging Time eos a RO REB 9 12 Linearity Range 9 13 Overload and Under Range 9 14 Oyerload Condition oie UTC Ee P REOS 9 14 Reset E He dae tes 9 14 Under Range Condition sss 9 14 Max Min and Peak Valesi imio ennan nie ntet ene nennen enne 9 15 Measuring for a Preset Integration Time sese 9 16 Timer uM OS t ro ete 9 16 iii ix 824 Reference Manual Measuring using User Selectable Thresholds sss 9 17 Chapter 10 Using the 824 Utility Software 10 1 824 Utility Installation aiii ie eo tertie e etate efe be 10 1 Starting the 824 Utility Software sess 10 2 Connecting to Your Computer sess 10 2 824 Utility Tool B t ttes de S RR RO ig 10 4 824 Utility Setup Window ccce dated teer 10 6 Retrieving setups from the 824 2 2 10 7 Modifying and Storing Setups to the 824 2 10 9 Changing Systemi Settings oen e oh aide wee 10 9 Manipulating a Setup
390. ion on TWA Leq SEL dose and projected dose calculations 824 Reference Manual 9 29 09 Appendix B Serial Port Remote Control Interface Explains how to use the Serial Port Interface for Remote Control of the System 824 Appendix C Technical Specifications Gives a listing of acoustic electronic environmental and physical characteristics of the System 824 Appendix D Glossary Contains Technical Definitions of key acoustical and vibration terms Appendix E Memory Usage Provides details on the allocation of memory when data are stored This information is particularly important for applications such as noise monitoring where measurements are performed and stored automatically over a period of days or weeks Appendix SLM Testing to IEC61672 1 Presents information for testing the sound level meter function of the System 824 according to IEC61672 1 Appendix G Miscellaneous Information Contains additional information about the 824 in the form of questions and answers Special Features of the Electronic Version Bookmarks Opening Bookmarks 9 29 09 There are a variety of special techniques for navigating through pdf documents which can greatly simplify finding specific items in this manual Two of these bookmarks and links are discussed below Bookmarks are clickable navigation tools in pdf files To open bookmark left click the upper Tab on the left of the Introduction 1 3 screen labeled Bookmarks
391. ional mode can be changed by sending commands through the serial port Data can also be downloaded to and settings queried and set by the controlling computer 9 29 09 A 1 The System 824 may be connected to the computer directly or through a modem network of instruments can be formed all controlled by one computer by using the address ability mode This chapter will describe the Serial Port interfacing of the System 824 and the various interface commands with their syntax Modem control is also covered Command text files and programming examples are available upon request via email to techsupport a LarsonDavis com Interface Cables The communication parameters are the following The baud rate is adjustable from 300 to 115200 baud 8 data bits parity is None and stop bits are 1 See section Communication on page 3 34 for a description of the communication parameters Serial Port communications are made through the 8 pin connector at A 2 824 Reference Manual 9 29 09 the base of the Model 824 The instrument s signals conform to the RS 422 standard and are compatible with RS 232C The connectors use the same pin out and cables as Apple Macintosh computers CBL006 824 to computer cable 9 pin female D CBL002 824 to serial printer 25 pin male D CBL003 824 to modem cable 25 pin male D CBLO91 824 to HP LaserJet 9 pin male D Connection to a com
392. is described in detail in section Turning On and Calibrating the System 824 on page 4 1 If the Cal Level is not already set to the level provided by the calibrator being used this level must be changed by the user To do this use the amp key to highlight Cal Level and press the key Use the horizontal and vertical arrow keys to edit the level to match that of the calibrator and press the key to enter the new value 9 29 09 Performing a Sound Level Measurement 9 3 Entering the Noise Floor Values When measuring low levels of sound substantial errors can occur when the sound level to be measured is near that of the noise floor of the measuring instrument An accurate measurement is obtained when the measured sound level is at least 10 dB above the noise floor When this condition is not fulfilled we say the instrument is in an Under Range condition which we indicate on the display The noise due to the front end electronics and the microphone preamplifier are known but the thermal noise of the microphone must be entered by the user based on specifications provided by the manufacturer The A weighted noise floor values for Larson Davis microphones are presented in the following table Microphone Model Number Nominal Thermal Noise dB A 2520 30 2530 2540 377 41 2559 377 2570 2575 60 31 20 15 18 15 10 10 The procedure for entering the noise floor value for the microphone t
393. is inserted into the opening on the side of the artificial ear base and threaded into place A microphone extension cable connects the microphone preamplifier to the input of the System 824 One of the audiometer earphones connected to the audiometer via a cable not visible here is placed on top of the artificial ear and then the weight is placed on top to hold it firmly in place 13 2 824 Reference Manual 9 29 09 Selecting the 824 AUD Operation Mode 9 29 09 To enable the 824 audiometer testing firmware option turn on the 824 IDSustem 8274 an Enter Company Enter Address Line 1 Enter Address Line 2 Serial Humber Also 3 129 29 Jun2668 After the start screen is appears press SETUP and use the arrow keys up down arrows 43 W to highlight the AudTest AUD setup or your customized AUD setup P Aud Test AUD Press the check key to retrieve the AudTest AUD setup The Linearity FFT display will appear inearity FFT Ho Data Available AUD Optional 13 3 Microphone Sensitivity Calibration A more detailed description of the calibration procedure can be found in the section Turning On and Calibrating the System 824 on page 4 1 AUD Modes 13 4 Press the VIEW key to open the View Menu View AUDY SLHA RTA EFT ow FFT ER LI Highlight SLM RTA and press the check key to obtain the SLM RTA Live screen shown below PLA R TA Live
394. ise Dose D 2 5 nt Rte Rede Re RH E D 16 Noise EXpoSUEe needed e ORE ER ests eR edit D 17 OSHA Level EOSEIA tenete CER dede D 17 Preamplifier ue Hte e d REOR Ws ae D 17 Projected Noise Dose siete tee e eed D 17 Single Event Noise Exposure Level SENEL LAX D 17 sui D 17 Sound Exposure SE ertet c cuve RN REP D 18 Sound Exposure Level SEL D 18 Sound Pressuite 5 xe tede Eme GI E ete P ORE D 19 Sound Pressure Level SPL Lp D 20 Sound Power W ccccccccescessessesssessecseessecsecsenseeeseeeeceseseeeeeeeeeeeeeaeeeseeneenaes D 21 Sound Power Level PWL LW horien ocior onie at a eene D 21 Sound Speedi C s oes tte SR eS D 22 Spectrum Frequency Spectrum ssseeeseseesersrseesseeessrsssesreresresessesesseene D 22 Threshold Sound Level Lt sse D 22 Time Weighted Average Sound Level TWA LTWA TC D 22 Time iret t e f ceti eos D 23 Vi bratiOTi rerit irre EE D 23 Wavelength D EE E Sb D 23 Wavenut ber k uice egt quietis D 23 Appendix E Memory Usage E 1 LOG Memory Usage eoe nete ote et ee a e dE e rece ERE E 1 Exceedance Records Exceedance History E 1 Interval Records Inty History Enabled
395. isplay ze RR ER AER TREE RR 5 47 Intervals d Display t er m d RE 5 48 Intervals e Display cete ee ERR Idus 5 49 Intervals f Display eese eene 5 50 Exceedance History soie HERE IE CER RE ERE 5 52 Excd a Display ide REN er ad ebd e tent 5 52 824 Reference Manual Excd b Display ies eene ite 5 53 1915 p ure o i edi nete 5 54 Time History Display sess 5 55 Daily Views stie teet tecto ei nee 5 58 Dalya Display deett 5 58 Daily b Display eR ie RR Re I e IRE 5 60 Daily c Wind Display essere 5 61 Daily d Windy Percent Display sse 5 62 Hourly Ged Display ERR here RR RD 5 63 oie eB e RB TS 5 65 Metrics a Display ect tu 5 65 Metricssb Display uni ue RR EUREN Es 5 66 andit coed ce e ER EHE QUEE e OT UR YR e TERCER XE 5 67 5 69 REGI 5 69 Wind b Display 23 oce ER REA TH VEU 5 70 Wind c Percent Display sse eene 5 71 Chapter 6 System 824 Virtual Instruments 6 1 System 824 Virtual Instruments ssssssssssesee eene enne nnne 6 1 Selecting an Instrument este taie ete ARREARS Keo 6 3 Sound Spectrum Analyzer SSA
396. isplay shows the A weighted TWA Leq over the duration of the measurement C minus A Weighted TWA This display shows the C weighted TWA Leq minus the A weighted TWA Leq over the duration of the measurement The Ln Centiles View has two displays which can be accessed by simply selecting Ln Centiles with the Y Check key from within the main View menu then cycling through the views with the D and 4 arrow keys until the desired display appears The Ln a display consists of two major components Display label Percentile values amp levels The Ln Centiles a display is shown below for the LOG instrument System 824 Views 5 35 Percentile values amp levels Display label 5H L n a r Li B7 LB 23 BBS z 33 3 50 0 LEE 7 90 0 67 6 Percentage settings are entered with a 1 100th dB resolution but are displayed to the nearest 1 10th dB when 10 dB or greater Ln b Display 5 36 The following explains each of the display s components Display label Shows the current display for example Percentile values amp levels The L percentile levels level is that level which is exceeded n percent of the measurement time By modifying the six settings you can select any six percentile values to be displayed at a time For example if you set one of these settings to 10 5 then 105 would be one of the six percentiles that is display
397. it your specific needs and then save it for later use The details on each setting is described for the SSA ISM and LOG instrument types This chapter covers the following Recalling ID Setting Files Customizing Settings Menu Layout of SLM amp RTA SSA Settings Menu Layout of High Dynamic Range Integrating SLM ISM settings Menu Layout of Logging LOG SLM Settings e Check Menus Recalling ID Setting Files The procedural steps for recalling an ID setting file is identical for all the instrument types 1 e SSA LOG ISM The SETUP key activates a menu that lists the active ID and all stored ID s They are sorted in the order of most recently used first If an ID is permanent i e created by Larson Davis and not detectable or changeable it will have a p just to the left of its name in the SETUP menu These 9 29 09 Using ID Setting Files 7 1 If you have taken data that has not been stored or if the instrument is not reset you will be prompted with Data not Saved Save Answer Yes to save the data No to have the data reset or cancel to cancel the ID recall Customizing Settings permanent ID s are a good starting point for creating your own custom ID To activate an ID press the down or arrow keys to highlight it and press the CHECK key The ID is then recalled the menu closes and one of the previously viewed displays is shown Data using these settings may now be taken or
398. ither of these levels If the calibrator and instrument are near room temperature and near sea level then no other corrections need to be made If the calibration sheet for the CAL 200 indicates 113 98 dB for it s level when set to 114 dB then set the Cal Level in the 824 to 113 86 dB When the microphone and instrument are at a temperature other than near room temperature or static pressures not near sea level then corrections need to be added for the ambient temperature and the prevailing static pressure Check the calibration data shipped from Larson Davis with the CAL200 to get these corrections The corrections can be added to the level obtained in the previous paragraph to get the actual level of the CAL200 The 377 41 microphone s sensitivity varies with static pressure The coefficient of static pressure is 0 01 dB kPa If the system is calibrated at 85 kPa for instance then it will be 0 16 dB less sensitive at sea level The 377B41 and 824 vary with temperature The coefficient of temperature is 0 012 dB C If the system is calibrated at 25 C then it will be 0 024 dB less sensitive at 23 C Overview 2 17 824 Reference Manual 9 29 09 Front Panel Keys Functions and Menus This chapter contains an overview of the functions which are accessed through the System 824 keypad see Figure 3 1 below Figure 3 1 System 824 Keypad The 14 keys on the System 824 keypad are organized into these four sections Powe
399. itivity is reduced by 20dB which has the effect of moving the instru ment s available dynamic range upward relative to the normal range Therefore you can measure higher level sounds effectively The benefit varies depending upon the weighting or octave filter that you are using Using ID Setting Files 7 7 NOTE The Range setting is not meant to be switched dynamically in real time in part because selecting the High option requires stabilization period Furthermore the System 8245 large dynamic range 110dB ofien makes dynamic range switching unnecessary The Range setting merely allows you to move the available dynamic range either up or down when you need to measure extremely high or low sound levels Transducer Setting SSA LOG ISM NOTE Using an electret microphone with the polarization voltage supplied with the condnsr option will change the microphones sensitivity frequency response characteristics NOTE The frequency characteristics of the 377B41 amp 377460 microphones change sufficiently enough in high range as to no longer meet Type 1 standards Thus we recommend using the normal sensitivity microphones such as 2540 amp 2559 to measure high amplitude signals NOTE The transducer setting is a system setting that is not saved or recalled with an ID even though it appears in the SETUP menu Random Incidence Microphone Correction Available to all Instrument types Transducer
400. keep the detector detector time and detector store rate settings The live data current If the sample time Live display is updated regularly when the 824 is running is less than 0 25 seconds the display still updates every 1 4 second Display label RTA Live Current filter level in dB 33 3 ux S THEE Bandwidth 1 1 or 1 3 oct 39 BD gt e Selected filter frequency gt isos op MN Live spectrum s duration p nusn 1 1 octave cursor 11 20 824 Reference Manual 9 29 09 Press the View key again to display the View RTA menu Press the up W down arrow keys to highlight the desired display and press the V check key to select the highlighted display Leq The Leq display shows the equivalent level of all the samples A current or overall reset will reset the Leq Display label _ RTA Leg Filter level in dB _ ___ 6 cae ea UEM Bandwidth 1 1 1 3 oct gE BU aman Selected filter frequency 1AAAHZ ie Leq spectrum s duration 11 43 54 1 1 octave NOTE Leq Max and Min are measured only while triggered if triggering is enabled If triggering is disabled they are measured while the 824 is running by pressing the R S key If Autostore is enabled Leq Max and Min will be reset at ever
401. l be 5 of the true value This procedure requires evaluating the sensitivity of the transducer in decibels relative to volts The sensitivity of the transducer is usually provided in the manufacturers specifications To convert sensitivity to decibels use the following formula Linear Scale dB 20Log 1 volt sensitivity Example The sensitivity of an accelerometer is typically provided in units of V g Using an accelerometer having a sensitivity of 50 mV g the Linear Scale would be calculated as follows 26 0 dB 20Log 1 volt 0 05V 824 Reference Manual 9 29 09 The following table gives some examples of some typical Linear Scale values for common accelerometer sensitivities Sensitivity Linear Scale dB 100 mV g 20 dB 50 mV g 26 dB 25 mV g 32 dB 10 mV g 40 dB 9 5 mV g 46 dB g 14 0 mV Pa 37 08 dB Pa 2540 44 5 mV Pa 27 03 dB Pa 377B41 11 7 mV Pa 38 64 dB Pa 2559 47 5 mV Pa 26 47dB Pa 377A60 Obtaining a readout in units other If the desired linear units are different from those provided than g by the manufacturer m s for example calculate the sensitivity in those units Volt m s and use that value in the equation for Linear Scale Setup of Linear Units Readout The items to be defined to implement this feature are Linear Units and Linear Scale which appear in the FFT Edit Settings menu as shown in Settings Menu on page 12 1
402. l settings SSA with time histories set for 5 seconds dividing line setup not used otherwise Menu items 1 through 6 are custom IDs Note that for ID number 6 underscores were used as a separator to put a break in the list between the permanent settings and the user setting The list is sorted by what is used most often so if a permanent ID 18 used it will be seen above the line In other words the IDs that are used most often float to the top of the list and those that are not used sink to the bottom To make the underscore filename easily do the following 1 2 Recall an ISM instrument or any other ID as desired Press SETUP and highlight the top line Edit Settings and press the TOOLS key Highlight the top line Save ID and press the check key A window pops up labeled ID Name Press the RESET key to clear the old name Push the right arrow key seven times to get to the last name charac ter Press the down arrow key about eleven times until the underscore character is showing Press the check key Now recall all of the IDs that you want to be above the separator line 824 Reference Manual 9 29 09 Question 2 Answer Power Not Charging What is the power or current drawn by the 824 through the external power Jack Here is a sample of external power expectation showing both wattage and current LOG Running with backlight OFF LOG Running with backlight ON SSA Running wit
403. lable IDs 6 2 824 Reference Manual 9 29 09 Selecting an Instrument ID There will be a gt to the left of the currently enabled instrument ID The current ID will generally also remain at the top of the list If the user changes the ID that is in use the current ID will then have an asterisk to the left of the title To select one of the System 824 instrument setups or IDs do the following Step 1 Press the SETUP key A menu similar to the following appears Setup zo Edit Settings SLI ISM 25LHM ISH PSLMAaRTA SSA PLogg ing LOG Step 2 Select the desired ID from the menu by using the or 5 keys to highlight it then press the key to select it That instrument s main display will appear SLH TFTH n SPL Slow dp UU o B inm BD Leg ED 2 1 Sound Spectrum Analyzer SSA There are applications which call for the simultaneous measurement of both the sound pressure level and the real time frequency spectrum Very often you will wish to measure the weighted A C or Flat sound pressure level while simultaneously measuring the unweighted frequency spectrum For these applications the System 824 provides the SSA instrument 9 29 09 System 824 Virtual Instruments 6 3 SSA Measuring Ranges Measurement Range SSA mode only With this instrument the SLM and RTA functions are operating simultaneously The primary indicator range o
404. lay device will display all levels over the entire linear operating range on all ranges The typical time interval needed to stabilize after changes in environmental conditions is as follows Foratemperature change of 5 C the time is 30 minutes Fora static pressure change of 5 kPa 15 seconds For a humidity change of 3096 non condensing 30 minutes The Larson Davis model 824 was not tested for field strengths greater than 10 V m The mode of operation of the 824 that produced the greatest radio frequency emission levels was with the 824 set to ISM mode and with 010 10 microphone extension cable used to connect the PRM902 to the 824 AII ranges were the same Radio frequency emission in other modes 824 Reference Manual 9 29 09 Effect of Electrostatic Discharges Greatest Susceptibility to AC Power and Radio Frequency Fields 9 29 09 LOG and SSA are the same Adding the RS232 cable did not increase the radio frequencies emission levels The System 824 is not affected by electrostatic discharges The mode of operation of the 824 that produced the greatest susceptibility to A C power frequency and radio frequency fields was with the 824 set to ISM mode RS232 cable attached and with an 010 10 microphone extension cable between the PRM902 and the 824 F 7 F 8 824 Reference Manual 9 29 09 APPENDIX Question 1 Answer You may test drive or demo any of the non purchased
405. le 3 is a user defined macro which is programmed by the Group command Code Description Response O1 Read SLM data nnn n nnn n nnn n nnn n lt CR gt lt LF gt R 4 SPL R 11 TWA R 17 Lmin R 21 Lmax lt CR gt lt LF gt 02 Read Wind Data nnn n ccc nnn n nnn n lt gt lt 1 gt 03 Read Group of R vari lt as programmed gt ables programmed by the group programming com mand G n r O4 Read 824 s LCD Display lt SOH gt lt HIGH_COUNT gt lt LOW_COUNT gt lt data gt lt C bit mapped in a binary for HKSM gt lt CR gt lt LF gt mat There are 1024 bytes of screen data 8 lines of 128 bytes each Bits in each byte represent a vertical column of 8 pixels with the Isb on top O6 History Records R92 nnnnnn nnnnnn nnnnnn nnnnnn nnnnnn nnnnnn Run Log R93 Excd R94 Intv R95 Time History R96 Daily R97 Cal Log A 28 824 Reference Manual 9 29 09 Code Description OS AUD FFT Response Read THD data Fund Frequency Fund Level THD n 2nd 3rd 4th 5th and above nnnnnn nnn n n nn n nn n nn n nn 09 AUD FFT Read Fund Frequency and Fund Level nnnnnn nnn n Group Read Programming The group command permits the programming of user defined macro with up to eight 8 Read variables The macro is executed with the GO or O ther 3 commands which returns the list of defined read variables Use the following c
406. le later in this chapter please do not press any keys Although we will not do this in the present example we could highlight Detector noting that it is presently SLOW press D to open a window listing the SLM Detector selections highlight FAST and press Y to select it as the new SLM Detector Regardless of the Instrument Type one can modify any of the available parameters by selecting the proper Setup menu item then the proper sub menu item then making a selection and pressing Y Once one or more modifications have been made the user can follow one of three procedures Setup will close the menu remembering its location the next time it is opened Use the right 4 arrow key to step out one menu at a time Press power to close the menu and reset the menu position In either case the instrument will be ready to perform a measurement The major difference is that the second method backing out by a sequence of 4 keys possibly interspersed with and W keys leaves a memory of the path used to withdraw To better understand what happens when we back out of the Setting menu structure using repeated presses of 4 consider the following diagram illustrating the actions which 824 Reference Manual 9 29 09 9 29 09 have been taken so far in the example above F SLM RTA SLM un 4513 ine In this particular instance when the D key was used to move from t
407. lectromagnetic compatibility Generic immunity standard Part 2 Industrial environ ment C 2 824 Reference Manual 9 29 09 NOTE The 824 does not meet IEC 61672 1 IEC60804 or ANSI 81 4 specifications when used with a high sensitivity microphone 377841 or 377460 and a 20 volt bias The bias is changed to 20 volts for high range measurements in the ISM and LOG modes and 10dB or 20dB gain in all other modes 9 29 09 System 824 Main Characteristics Class 1 Precision Integrating Sound Level Meter with real time 1 3 Octave Filters classified as group X for the emission of and susceptibility to radio frequency fields 2MB standard memory Large backlit graphic display 64 X 128 pixels Icon driven graphic user interface Soft rubber backlit keys Large dynamic range RMS Detectors Slow Fast Impulse Triple Peak Detectors A C FLat Interval History statistical Time History Ln statistics 0 01 through L99 9 available Histogram tables Direct report printouts to laser printer Windows based software for setup control and high speed data download and reporting Advanced Windows based software packages optional provides data archiving search capabilities post measure ment analysis features and advanced sorting and graphics report generation tools Multi tasking processor allows measuring while viewing data transferring data or printing Prog
408. les sese A 68 Print Command a uu oeque pnto a bad on 69 Error Messages and 71 Modem Control Mode 0800 74 Modem Modes sre p A AP HR ESAE 74 Dial Out Mode aee reo Rae te das 74 Monitor NUmb6E dubai tette Me 75 824 Phone Dialing Procedure esses 75 Model 824 Answering Procedure 76 iii xiii 824 Reference Manual Unsupported Miscellaneous Commands sse 78 Data Eile Commiands ihe tet eet te dba 79 Keyboard Simulation sse A 80 Operation Notes eto e LS p tiet ee do A 81 Appendix B Integrated Level Calculations B 1 Appendix C Technical Specifications C 1 Declaration of C 2 1 3 Octave Filters repere edet ee terere C 20 Er quency Ratig s one ed cate dro re ies C 20 Filter Shapes ied eee ee e te de dedos C 20 Frequency Response 5n c iecore a Pene ree WERE RE C 24 Power Current Draw of 824 Using External Power esses C 49 Appendix D Glossary D 1 Allowed Exposure Time rece a ae EE E EE D 1 Average Sound Level 1 02 2102 30 2 0041000000000000000000000000004 D 2 Community Noise Equivalent Level CNEL
409. lized to 1000 00Hz 8 0 Tested 03 06 01 07 07 35 by James Higley Note Prepolarized Microphone with windscreen Reference Mic B amp K Model 4133 Serial Number 1424039 Tested 03 01 01 08 20 13 1K Hz Type 1 limits Directional Characteristics of the 824 with the 2540 377B41 and 2551 free field microphones Test Setup The 824 was tested in two different configurations as fol lows 824 oriented with the LCD facing up 824 oriented on it s side Definitions The XY plane is defined as the 824 oriented with it s LCD facing up The YZ plane is defined as the 824 oriented on it s side 9 29 09 C 33 Graph 1 824 in the XY plane fitted with the 2540 microphone 1 kHz i 2556 6 NS SAT 150077 152297 A Graph 2 824 in the XY plane fitted with the 2540 microphone 2kHz Vp EIE 22 A OZS VEL SS COLT SELL 250 Li Dar SSE 0 34 824 Reference Manual 9 29 09 9 29 09 Graph 3 824 in the XY plane fitted with the 2540 microphone 4 kHz NN gt 2 2 22 Li I m 200 e EX Graph 4 824 in the XY plane fitted with the 2540 microphone 8 kHz Graph 5 824 in the XY plane fitted with the 2540 microphone 12 5 k
410. llowing menu appears after pressing the Check Y key intervals 5 Following is a chart of the check menu with a description of each menu item Menu Items Purpose Leq Spectrum Allows you to view the Leq spectral data Max Min Spectra Allows you to view the Max or Min spectral data Ln Spectrum Allows you to view the Spectral Ln data Locate Locates a specific interval record Settings Modifies the interval settings In the Leq Spectrum display press the Check V key and the following menu appears 9 29 09 Using ID Setting Files 7 67 Intervals Bu Tine Following is a chart of the Leq Spectrum check menu with a description of each menu item Menu Items Purpose ByTime Allows you to view the Leq for each interval over time Intv Data Allows you to view the nterval a through nterval e displays Max Min Spectra Allows you to view the Max or Min spectral data Ln Spectrum Allows you to view the Spectral Ln data Locate Locates a specific interval record Settings Modifies the interval settings Graph Changes the scaling of the Leq Specta graph Bandwidth Changes the filters to either 1 1 or 1 3 octave Time History Check Menu Press the Check Y key while viewing either of the Time History displays and the following check menus appear 7 68 824 Reference Manual 9 29 09
411. lues for the frequency displayed Selected frequency Shows the values for the frequency shown on the display System 824 Views 5 21 Percentile values amp levels The Ln percentile levels level is that level which is exceeded n percent of the measurement time for the frequency band By modifying the six settings you can select any six percentile values to be displayed The settings may be changed at any time spectral Ln data are only calculated while running To view the spectral Lns in graphical form highlight Spectrum 1 and press the check Y key Use the amp and down W arrow There are six displays showing all of the frequencies for keys to move from one spectrum Ln each of the six Ln values display to another 5 22 Below is an example of one of the Spectrum displays Display label 9 SSR L nl f Ln percentage _pe 1 67 iz pees Selected frequency 9 zzpmnz 5 i TE Elapsed time We nn 06 87 Graph of Ln at each frequency The following is a brief description of each of the components of this display Display label The Display label identifies the display which is the SSA Ln 1 f display showing L 1 67 for all of the frequencies in graphical form Ln percentage Shows Ln percentage being displayed Levelat selected frequency This shows the Ln l
412. m Level nnn n dB I6 SSA LOG Lmax nnn n dB I7 SSA LOG Lpeak nnn n dB I8 SSA LOG UnWeighted Peak nnn n dB I9 SSA LOG RMS Exceedance Count nnn I10 SSA LOG Peak Exceedance Count nnn SSA LOG UnWeighted Peak Excd Count nnn 112 SSA LOG Overload Counts nnn 113 LOG Intv Ln 1 Percent nn 9 29 09 A 61 Commands Instrument Description Comments Type I14 LOG Intv Ln 1 Level dB nnn n I15 LOG Intv Ln 2 Percent nn I16 LOG Intv Ln 2 Level dB nnn n I17 LOG Intv Ln 3 Percent nn I18 LOG Intv Ln 3Level dB nnn n I19 LOG Intv Ln 4 Percent nn I20 LOG Intv Ln 4 Level dB nnn n 121 LOG Intv Ln 5 Percent nn 122 LOG Intv Ln 5 Level dB nnn n D3 LOG Intv Ln 6 Percent nn 124 LOG Intv Ln 6 Level dB nnn n I37 n SSA RTA Filter Leq n ANSI filter nnn n dB I38 n SSA RTA Filter Leq n ANSI filter nnn n dB 1101 SSA LOG Intv Macro Variables 1 12 37 38 I101 RTA Macro to 4 I Commands for Basic SLM Mode Commands Instrument Description Comments Type I5 n SSA LOG Any SPL 1 to 9 nnn n I6 n SSA LOG Any Max 1 to 9 nnn n I7 n SSA LOG Any n 1 to 9 nnn n A 62 824 Reference Manual 9 29 09 Commands Instrument Description Comments Type I8 SSA LOG LAFTMS Takt5 A Fast nnn n 19 SSA LOG Intv Impulse Leq dB nnn n I10 SSA LOG
413. m the Setup Menu by pressing either second time 4 the instrument is ready to perform a measurement as defined by that Active ID Active ID ERE ISH gt SLM P Logging Following the Active ID is a list of the available IDs In most cases the first ID in the list will have the symbol gt to the left indicating that the Active ID was originally defined by selecting that ID Thus the name of the Active ID and this ID will be the same If there is an asterisk to the left of the Active ID it indicates that modifications have been made to the Active ID since the selection of the ID below it so they may no longer be the same If there is no asterisk then the Active ID and the one below remain identical Quick Start 4 13 Asterisk to indicate that Edit Settings active ID has changed 9 HSULMERTA Soh gt SSA LOG SLM ISH There is one other possibility which should be mentioned When a stored data file is recalled then the ID stored with that file becomes the Active ID Since the ID which was used to perform the measurement at that time may have since been modified or even deleted a tilde will appear to the left of the Active ID to indicate that it is approximately the same as another ID in the list 4 14 824 Reference Manual 9 29 09 Menu Scrolling Permanent IDs 9 2
414. mber of samples taken in the measurement the sample rate is 32 samples per second and is the calibration offset that corrects for various sensitiv ities of microphones Accuracy is maintained by having large fixed point variables for the number of samples and the summation accumulator The limit of s is 4 294 967 295 samples and is stored in a 32 bit integer variable within the System 824 This limit is greater than 1553 days or greater than 4 years and 4 months The value that can be stored in the summation accumulator a 96 bit integer can be the overload level maximum allow able signal amplitude into the System 824 for the maximum number of samples Using large fixed point variables pre vents the inaccuracies obtained in systems based upon float ing point variables 824 Reference Manual 9 29 09 SEL Calculations SEL 1s available for both the overall and current measure ments and is calculated using this formula Lo Laws Lea tke log V 10 10g 32 TWA cal s l Since the sample rate 15 32 samples per second and SEL 15 based on time in seconds the log 32 is subtracted from the log of the accumulation to perform a division by 32 of the SEL energy values in the analyzers utilize the Threshold and Exchange Rate settings Care should be taken when modifying these settings since some standards or govern ments require SEL to be taken without a Threshold set it to zero and with an Exchange Rate
415. me occurs from 10 p m to midnight They are energy summed and converted to an average noise exposure rating A logarithmic form of any measured physical quantity and commonly used in the measurement of sound and vibration Whenever the word level is used this logarithmic form is implied The decibel provides us with the possibility of representing a large span of signal levels in a simple manner as opposed to using the basic unit Pascal for e g acoustic measurements 824 Reference Manual 9 29 09 9 29 09 It is not possible to directly add or subtract physical quantities when expressed in decibel form since the addition of logarithmic values correspond to multiplication of the original quantity The word is normally attached to a physical quantity when expressed in decibels for example Lp represents the sound pressure level The difference between the sound pressure for silence versus loud sounds is a factor of 1 000 000 1 or more and it is very unpractical to use these large numbers Therefore a measure that would relate to the number of zeros would help for example 100 000 would be equal to 50 and 1000 would be equal to 30 and so on This is the basic principal of the dB measure dB values are unit free and therefore the dB value is not the value of the quantity itself but the ratio of that quantity to an actual reference quantity used Thus for every level in decibels there must be a well defined refere
416. measurement file to a user defined spreadsheet program This button will only be active when you are in the translate section of the program and there is a measurement file being displayed 824 Utility Setup Window The setup window is the default window that will open up when the 824 Utility program is started The setup window will allow you to edit existing setups retrieve setups from the 824 or a file create new setups and store setups to the 824 or to a file The main setup window has 2 sections the setup list box and the settings dialog section The setup list box will list all setups that have either been created or retrieved from the 10 6 824 Reference Manual 9 29 09 824 or a disk file The settings dialog section will allow you to manipulate the setup Utility BIx File View Setups Data Help of 214 Setup List Box Title Options Calib Power Date Time Controls Modem D System D j 824 System Settings Instrument Labels Model Larson Davis Model 824 Serial Number A0138 Revision 3 128 23Jun2000 Instrument Type SSA Active Setup SLM amp RTA Instrument Name Enter Company Name Description 1 Enter Address Line 1 Enter Address Line 2 For Help press F1 Settings Tab Dialog Retrieving setups from the 824 Setups stored in the 824 can be retrieved by clicking on the Get Setup button on the tool bar or by selecting Get Setups From 824 from
417. measurement will end at the real time indicated in the second column the hh means any hour and the hh m means any hour and tens of minutes All subsequent intervals will now be synchronized to the real time clock Intv Sync On Sync to nearest Period 01 00 hh 00 hour 00 30 hh 00 hh 30 half hour 30 minutes 00 20 hh 00 hh 20 hh 40 one third hour 20 minutes 00 15 hh 00 hh 15 hh 30 hh 45 one fourth hour 15 minutes 00 10 hh mO one sixth hour 10 minutes 00 05 hh m0 hh m5 one twelfth hour 5 minutes 00 0x hh mm minute Commands Instrument Description Comments Type 10 01 or variable greater that 4 will run macro by default SSA LOG Date and Time of Occurrence ddmmmyy hh mm ss RTA FFT TAL 12 SSA LOG Duration hh mm ss mm ss ss TAL A 60 824 Reference Manual 9 29 09 Commands Instrument Description Comments Type D RTA Number of Samples Averaged nnnn D FFT Count nnn 13 SSA LOG TWA nnn n dB I3 RTA Spectral or Flat Level n ANSI nnn n dB filter I3 FFT OVER LOAD TAL Overload Counts nnn I4 SSA LOG SEL nnn n dB I4 RTA Note Field I4 FFT Overall Level nnn n I4 TAL Mode SLM RTA I5 SSA LOG Lmin nnn n dB I5 n FFT FFT Line Level n 0 to 400 nnn n I5 n RTA RTA Live Spectrum Level nnn n dB 16 n RTA RTA Leq Spectru
418. measurements can also be performed as described in Linearity RTA Display on page 13 10 Linearity FFT Display on page 13 14and Flatness FFT Display on page 13 18 corrected by using coupler earphone RETSPLs microphone or other such corrections to arrive at the dB HL value Linearity evaluation can easily be performed by placing the cursor on the audiometric presentation frequency then varying the hearing level output and monitoring the measured level on the 824 Similarly cross talk measurements are performed with the non test earphone being measured then comparing the test earphone level to that measurement Any Level a b and c Displays Frequency is also available on the FFT mode displays using a more stable FFT frequency calculator 13 8 The Any Level Displays a b and c are accessed from the SLM RTA Live display by pressing the down arrow key V The Any Level a display shown below displays Flat weighted broadband SPL values for Fast and Slow simultaneously nu Level a X Ba 85 6dBF The Any Level b display shown below displays the Fast SPL for A C and Flat frequency weightings simultaneously nu Level b Ba 85 B2 4 Both the a and b displays show the output of the frequency counter showing Frequency and Period The frequency counter is a hardware count based on zero crossing significant amplitude is needed to ensure an accurate r
419. ment This setting identi fies the instrument within a network of instruments by assigning it a network or serial address Serial Conn L 96081 Caza Serial Control Flow Control Flow control of the serial connection Flow control can be changed to None Hardware Xoff or Both Flow control prevents the loss of data when either the instru ment or controller s input buffer becomes full Hardware flow control is recommended Flou Contro Hone xHdwuwr i XOF Both Modem Mode Turns the modem mode on or off to allow communication to a telephone modem Front Panel Keys Functions and Menus 3 35 Serial Comm Dial Out Mode The 824 will dial out on an Exceedance or an Alarm or both Serial Comm Hodem Mode Hal Dial Out Mode I L Hone Dial Out Mode Phone Number The 824 will dial the phone number entered here on the events selected in the dial out mode Serial Comm Honitor Number Monitor Number The monitor number is used to identify which 824 is being queried and is sent with the 824 s initial announcement 3 36 824 Reference Manual 9 29 09 Serial Comm CHone Phone Honitor Humber Ceesig Modem Init The modem initialization string is entered here Serial Comm Initialize The modem initialization string is sent out the RS232 po
420. ment ID do the following to select the desired view Step 1 Press the button and a screen similar to the fol lowing will appear Intervals Time Histor Step 2 Use the and arrow keys to highlight the desired view 824 Reference Manual 9 29 09 SLM Views The SLM view is available to the ISM SSA and LOG instruments 9 29 09 Step 3 Press the Check Y key and the desired view will appear The SLM view shows the SLM data with a graphic display of Time History In this graphical format a running time history based upon 1 second Leq values is scrolled across the screen showing the levels of the last fifty samples New data points correspond to the detector and weighting selected by their respective settings The larger digital display indicates the SPL for the selected values of detector and weighting The smaller digital display indicates the level corresponding to one of the secondary parameters which are being measured concurrently The SLM view display consists of eight major components Display label Selected detector Current SPL reading Selectable Leq reading Weighting Elapsed time Status SPL history graph System 824 Views 5 5 Weighting displayed Selectable reading Display label SPL Current SPL reading A 4 Elapsed time 41 1 H8 A TH f lt t Status Slow Ti detector displayed deo
421. ment s clock b emng p m For example 5 p m will calendar and timer The first three menu items allow you to be displayed as 17 00 00 set the current time date and day respectively while the remaining items Run Stop Date Run Stop Time 1 Run Stop Time 2 allow you to control the timer function IF the date has not been set month Current Time Date To set the current time and or date shows as then the message highlight the desired item i e Time or Date and then press Time not set will be shown when the D key Modify the setting using the 4 D key to the Run key is pressed select the digit desired to modify then use the W key to modify 3 24 824 Reference Manual 9 29 09 Clock Timer current thn hh iam isc Lj LII HEGRE Cicurr ent Patel 6 S77 l Dag OF MEER Day Of Week Allows you to change the current day of the week Use the W key to highlight the desired day then press the key to select Da Of Heek Tue Hed Thu Fri Timer Mode The timer is used when you want to have the 824 automatically turn on gather data and stop at pre deter mined date s and time s The System 824 has four timer modes automating the start and end of measurements Zr Da Off The timer is disabled 9 29 09 Front Panel Keys Functions and Menus 3 25 Block The timer will automatically turn the ins
422. mulation The keys on the 824 s keyboard may be simulated with the K I O command Each key is given an ASCII character as shown in the table below A space delimiter following the K is required before non numeric operands i e K 6 lt The keyboard buffer will hold up to 8 keys K12345678 is acceptable A 80 ASCII Charac ter Key that is simulated 0 CHECK KEY 1 POWER KEY 2 RESET KEY 3 PAUSE KEY 4 RUN STOP KEY 5 UP ARROW 6 DOWN ARROW 824 Reference Manual 9 29 09 Operation Notes LEFT ARROW RIGHT ARROW FUNCTION KEY 1 VIEW FUNCTION KEY 2 DATA FUNCTION KEY 3 SETUP FUNCTION KEY 4 TOOLS FUNCTION KEY 5 PRINT When using the Logic Input line in the LEVEL mode both I O and keyboard Runs and Stops inhibited If the line is High the 824 takes data and if the line is Low no data is taken The Pause mode will pause the data taking process while the line is high this may be triggered by high wind speed In the Toggle mode when the Logic Input line goes high the 824 toggles between RUN and STOP modes 9 29 09 A 81 A 82 824 Reference Manual 9 29 09 APPENDIX Integrated Level Calculations Basic Integrated Level Calculations The Larson Davis System 824 calculates all of its integrated levels based on equations from IEC standard 804 IEC 804 Section 3 3
423. must sample the data sufficiently fast enough so that the errors are minimized for a given data variability Thus for fast the amplitude variability is greater so the sample rate must be faster Inside the 824 we sample fast enough that the integration 1s always accurate and gives you the Leq data at the time period desired i e all the energy received for that Leq period is contained within the Leq The old instruments sampled the SPL detectors and integrated the sample number so they had to sample them pretty quickly 32 samples per second for the LD 820 amp 870 You indicated that you are looking at a C weighted the frequency weighting doesn t matter SPL sampled every two seconds The worst case error between the Leq and the SPL is with an Impulse whose onset is immediately after a sample has been taken The decay for Slow 15 about 4dB per second and fast is 8 times faster at 32dB s In two seconds the next sample will read 8dB below that maximum for Slow and 64dB below the maximum for Fast Mind you that this 1s worst case You can plug that sawtooth waveform into a calculator and do an integration to get the Leq but you see that there can be a great difference potentially For example if the impulse had a max of 108dB and the sample two seconds after the max was 100dB the Leq would be 105 6 dB the SPL would be 5 6dB lower than the Leq would be for that worst case signal In the real world we do not get that type of signal too
424. n Stop It is within the Settings menu and its associated Sub menus that the settings associated with the measurement are defined Sound level measurements are made in the ISM LOG and SSA Instrument Types so all of these will include selections of RMS and peak detectors and broad band frequency weighting IDs based on the LOG Instrument type will include parameters associated with automatic data storage such as Interval and Time History periods and threshold levels for triggering Exceedance Event data Report settings are also included in the Settings menu when appropriate The following example will be used to illustrate the general structure and utilization of the Settings menu and sub menus Please follow this on your instrument Since all versions of the System 824 include the SSA Instrument Type we want to select the permanent ID SLM amp RTA SSA as the Active ID Press O to open the Setup menu Step 1 Ifthe Active ID in your instrument is an unmodi fied version of SLM amp RTA SSA press Y Step 2 Ifthe Active ID in your instrument is anything other than SLM amp RTA SSA then highlight SLM amp RTA SSA and press Y to make it the Active ID Quick Start 4 17 Step 3 Ifthe Active ID in your instrument is a modified version of the SLM amp RTA SSA indicated by an asterisk to the left of the name highlight SLM amp RTA SSA press Y and in response to the message Active ID has changed Save use D to highl
425. n addition Short the ByTime Spectrums are included in the Long report Long Lowest Record 0 65535 The lowest Autostore Record to print Highest Record 0 65535 The highest Autostore Record to print Lowest 0 65535 The lowest ByTime Spectrum to print ByTime Highest 0 65535 The highest ByTime Spectrum to print ByTime RT 60 Report No Prints the calculated RT60 for every octave or 1 3 octave band Yes Avg Hist No Spatial Average History Yes Lowest Record 0 65535 The lowest Spatial Average History Spectrum to print Highest Record 0 65535 The highest Spatial Average History Spectrum to print Setup Report No Print the settings and their values for the RTA instrument Yes 9 29 09 Printing a Report 8 27 8 28 824 Reference Manual 9 29 09 APPENDIX Performing a Sound Level Measurement Due to the many features of the System 824 and the variety of measurements it is capable of performing there is a great deal of instructive material in the preceding chapters In this chapter to assist the new user in performing a basic sound level measurement we work our way through the specific steps necessary to perform an accurate measurement Configuration of the System The System 824 should be configured as shown in Figure 1 1 on page 1 10 with the preamplifier connected to the front of the instrument and the microphone connected to the end of the preamplifier If desired a microphone extenstion cable may be connec
426. n of the settings Graph Changes the scaling of the instrument s spectrum graph 824 Reference Manual 9 29 09 Other Logging LOG Check Menus See SLM Check Menu Options SSA and LOG on page 7 62 for a description of the LOG SLM check menu Any Data Check Menu Current SLM Overall SLM Check Menu Exposure Check Menu 9 29 09 This section presents the LOG instrument s available Check menus that are in addition to the SLM Check menu previously described in this chapter See Any Data Check Menu on page 7 73 for a description Current SLM and Overall SLM views have access to the following Check menu SLM Settings Mark Settings gt Graph THA gt Menu Items Purpose Mark Puts a marker in the time history record if the check C key is pressed If the right rarrow key is pressed it puts you in the Marker screen Settings Modifies the SLM settings for the selected instrument Graph Changes the scaling of the instrument s SLM history graph TWA Modifies the TWA settings for the selected instrument The Exposure view has access to the following Check menu Using ID Setting Files 7 73 LN Centiles Check Menu 7 74 OLEI Criterion Menu Items Purpose Exchange Sets the exchange rate that is used to calculate the overall TWA Ovll Threshold Sets the threshold for computing the overall time weighted average
427. nce Battery Type ISM or LOG Mode SSA Mode 010 1200 mAH NiMH Pack Supplied prior to January 2005 4 1 hours 3 hours 010 2300 mAH NiMH Pack Supplied after January 2005 6 5 hours 4 5 hours Standard Alkaline AA eg Duracell MN1500 type LR6 4 3 hours 2 8 hours High Drain Rate Alkaline AA e g Duracell Ultra MX1500 type LR6 gt 4 4 hours 4 4 hours Photo Lithium AA e g Energizer e L91 2 7 5 hours 7 5 hours 2000 mAH NiMH AA Fast Recharging 5 5 6 8 hours 4 5 5 5 hours e g Ray O Vac I C3 15 minute charging time Memory Retention Memory retention without batteries or external power 5 minutes minimum Physical Characteristics Length 9 9 inches 25 1 cm Width 3 4 inches 8 6 cm Depth 1 6 inches 4 0 cm Weight 18 oz 0 51 kg 824 Reference Manual 9 29 09 Resolution Levels 0 1dB 0 01 dB via 1 Dose 0 0196 Elapsed time Highspeed RTA as rapid as every 2 5 mS all other instruments 0 1 second Real time clock 1 second Calendar 01 Jan 2000 31 Dec 2099 Cable Drive Capability with PRM902 preamp Frequencies to 20 kHz 700 feet 213 meters Frequencies to 10 kHz 1000 feet 305 meters Maximum Input Voltage overload Gain VRMS Vpeak dBuV 0 dB 2 54 7 2 128 10 dB 0 74 2 1 118 20 dB 0 254 0 72 108 30 dB 0 080 0 227 98 40 dB 0 025 0 072 88 50 dB 0 008 0 023 78
428. nce date and time m Display label p Hir 097271999 16 54 40 Record number fstore Filter level i in dB 2 3 Selected filter frequency 16 Autostore duration Number of autostore records Pressing the Y check key twice while in any of these display views will toggle you between the Leq Max and Min autostore displays The up and W down arrow keys will move you to the next or previous Autostore records 9 29 09 RTA optional 11 27 Press the View key to return to the View Autostore sub menu Autostore Press the 4 left arrow key to back out to the main View Autostore menu showing Autostore ByTime and RT 60 menu items View Autos tore Use the W down arrow key to highlight the ByTime menu item and press the D right arrow key to access the ByTime menu and displays The following View ByTime menu appears View BuTime ce lim al Press the Y check key to view the ByTime spectrums recorded during the Autostore 11 28 824 Reference Manual 9 29 09 Autostore ByTime Spectral History The Autostore ByTime spectral history has two displays for viewing the time history data The first is called the ByTime Spectrum and the second is called the ByTime Graph ByTime Spectrum The Autostore ByTime Spectrum display shows just one sample in time and the entire frequency spectrum with frequency on the
429. nce quantity Sound versus vibration uses different references but the dB principal is the same When the quantity equals the reference quantity the level is zero To keep dB values above zero the reference is generally set to be the lowest value of the quantity that we can imagine or normally wish to use Before explaining the calculation of dB values it is useful to remember the following rules of thumb when dB values are used for sound levels Doubling of the Sound Pressure 6 dB Doubling of the Sound Power 3 dB Doubling of the Perceived Sound Level approx 10 dB Note The latter is frequency and level dependent but the value 10 dB is a good rule of thumb especially around 1 kHz Table 1 shows the actual value of a specific item such as sound power for which the sound level is calculated First the sound power value is divided with the reference used and then the ten based logarithm is applied This value is then multiplied by 10 to create the decibel value see equation D 1 below For every 10 decibels a unit called Bel is created The decibel stands for deci for tenth and bel for Bel compare decimeter The relationship between Bel and decibel is thus 1 Bel 10 decibels It is not possible to directly add or subtract decibel values since addition of logarithmic values correspond to multiplication of the original quantity Power form squared units Level f
430. nd overall Spectral LN report Lowest Level 045 Selects the lowest SPL histogram level to be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 5 0 Selects the SPL histogram resolution Pk 1 Histogram No You can customize the Peak Histogram report by choosing the long or short report 8 12 824 Reference Manual 9 29 09 Tailored Report Template SSA instrument Histograms Lowest Level 110 Selects the lowest 1 histogram level to be printed Highest Level 140 Selects the highest Peak histogram level to be printed Resolution 5 0 Selects the Peak1 histogram resolution Pk 2 Histogram No You can customize the Peak2 Histogram report by choosing the long or short report Lowest Level 070 Selects the lowest Peak2 histogram level to be printed Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 5 0 Selects the Peak2 histogram resolution Tailored Report Template LOG instrument Report Settings Lower Level Report Settings Description Unformatted No A dump of all Read Query and Interval remote commands Multiple values are comma delimited Data Report Yes This shows general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Log Report Yes The run stop log and with the date and tim
431. nd the firmware version and date The System 824 then loads the last instrument definition ID selected Pressing the b POWER key for 1 second turns the power OFF Power off prior to changing microphone or preamplifier to avoid possible damage of sensitive electronics due to high voltage spikes This screen shows you the current power source battery level and external power voltage 4 2 Step 1 Turn on the System 824 To do this press the key located on the left side of the key pad By pressing this key the Larson Davis logo appears while a number of tests are performed The fol lowing screen then appears for a few seconds ID System 8 21 FA Enter Company Enter Address Line 1 Enter Address Line 2 Serial Humber Ai 28 1 247 255ep1998 Step 2 Check the battery level After the System 824 is turned on you can check the battery level To do this press the B POWER key momentarily The following screen appears PUR Source 15 Battery En External 1z2 BY Back light Contrast Hold to Ed off iu Step 3 Calibrate the instrument To do this press the TOOLS key The following menu appears 824 Reference Manual 9 29 09 NOTE The output level specified by the calibrator manufacturer will be at stan dard temperature and pressure In prac tice the level is a function of temperature and static barometric p
432. ndicates the order of the displayed interval in relation to the other interval records Interval Date Time The Event Date Time shows the time and date that this interval began Leq Reading The Leq Reading shows the for the currently displayed interval SEL Reading The SEL Reading shows the SEL for the currently displayed interval System 824 Views 5 45 Interval Duration The Interval Duration shows the length of time of the currently displayed interval Intervals b Display The Interval b display consists of six major components Display label Interval Number Interval Date Time Lmax Reading Lmin Reading Interval Duration The Interval b display is shown below for the LOG and SSA instruments Display label Interval b B 4 Interval Number Interval Date Time 2 199 11 82 56 Lmax Reading 9 8 Lmin Reading Lmin 39 B dBA Interval Duration Duration 16 24 36 The following explains each of the display s components Display label This shows the current display for example Interval Number The Interval displays each measurement interval in the order that they occurred The Interval Number indicates the order of the displayed interval in relation to the other interval records Interval Date Time The Event Date Time shows the time and date that
433. ne Cursor indicates 2 points on graph srap Bar shows one to one zoom meaning cursor indicates one point on graph 9 29 09 FFT Optional 12 7 While zoomed the display will scroll when the cursor nears either the left or right edge of the display FFT Check Menu Pressing the Check key while in the FFT display puts you in the check menu shown below EFT Hd Store Snapshot Settings Graph E The check menu offers the following options Store Snapshot Stores the current FFT spectrum at that moment in time The THD as calculated the 824 THD Activates the THD display which shows the satisfies all of the requirements for calculated THD ANSI S3 6 Settings Activates the FFT settings menu Graph Adjusts the vertical graph scale and offset See 824 Reference Manual Graph Level Allows numerical entry of graph level in dB Graph Scale Allows numerical entry of graph scale 12 8 824 Reference Manual 9 29 09 THD Total Harmonic Distortion The THD display shows the results of the THD calculations THD THD n percentile 9 n Harmonic percentiles pc e 4th amp higher harmonic 74th percentile lt q Fundamental frequency 11 3 15 998 THD n dB down 6 3954 42 SdB t Harmonic dB down 3657 485 9dB 3254 49 TdB 4th amp higher harmonic
434. ne e erat eri Rede 2 2 Write Protect aisi antis 2 2 Integrated Level Calculations eed tee e B 1 Interface Cables iuc fette tte ttt eee Ree te S e rp EP We ER HER A 2 Interval Urin M 7 38 Check Menu NE I EUREN dine PRG 7 16 displays cete thee deae eO eee eter t ee tt e Rea e tete 5 44 Enable ack ern enero tom anc tette 7 37 eee 7 39 lei 6 7 gg 7 37 save Ln s ecco ee DR Eee e 7 38 Spectral Bis eoa ere e Er SUI PE REEF 5 14 es Te ERI e BR RR eee eR Ee eee 7 39 Threshold tete EE et ette on nit neh 7 39 time SYNC iie tese eR REOR ER IRE t RE RE ERE RE 7 37 ISM Measuring Ranges oie ei cadet paese tede deeds ied 6 9 K Key AOW Keys m 4 3 11 Gd 3 12 rq 3 13 uERAPLUIIM Rm 3 2 hdd 3 10 PoWer ertet eee ie tete ete ep eene FORCE e RU 3 3 Print Key ahi i ee 3 37 ho dd PL 3 9 Run Stop Key et nie e RB URS Ee tue cat feed TR eee EU 3 8 Sina EE 3 14 Tools Key EE eae dies NI NI 3 18 Index Model 831 Technical Reference Manual VIEW Key edu ive
435. ne is held or mounted in such a way to minimize the effect of reflections on the sound field near the microphone Use of a Windscreen Wind blowing across the microphone generates pressure fluctuations on the microphone diaphragm which can produce errors in the measurement As a result when performing measurements in the presence of low level airflows it is recommended that a windscreen be placed over the microphone Larson Davis provides the WS001 windscreen a 3 1 2 diameter ball made of open cell foam 9 29 09 Performing a Sound Level Measurement 9 7 9 8 which can be placed over the microphone and preamplifier as shown below To install the windscreen hold the meter in one hand and the windscreen in the other Insert the microphone preamplifier assembly into the opening in the windscreen as shown below and slide the windscreen completely down over the preamplifier 824 Reference Manual 9 29 09 Selecting the SLM Display For sound level measurement press the key use the key to highlight SLM and press the key to obtain the display shown in Editing the Measurement Parameters on page 9 5 Selecting the Measurement Range ISM and LOG Modes 9 29 09 In the ISM mode there are three range setting available Low Normal High Although the range setting does not always appear on the SLM display it can be found by repeatedly pressing either the amp key until the highlight is located in the lo
436. ne with 44 1 mV Pa sensitivity The range is measured between a low limit of peak error gt 0 5 dB and a high limit of overload C 12 Peak Measurement Range LOG and ISM modes only Low Limit High Limit Range A WT high 73 148 75 A WT normal 53 0 128 0 75 0 A WT low 53 0 108 0 55 0 C WT high 73 148 75 C WT normal 53 0 128 0 75 0 C WT low 53 0 108 0 55 0 FLAT high 80 148 68 FLAT normal 60 0 128 0 68 0 FLAT low 60 0 108 0 48 0 SSA Mode Specifications IEC 61260 Class 1 Broadband Overall time weighting Slow Fast Impulse TWA and Peak 1 3 octave filter time weighting Slow Fast Broadband Frequency A C and Flat see Weightings table on page C 7 Dynamic range gt 93 dBA overload to noise floor Linearity range gt 80 dBA Pulse range gt 83 dBA RMS noise floor lt 33 dBA typical with PRM902 377B41 microphone and 0 dB gain Reference level range 0 dB gain Exchange rates 3 4 5 or 6 dB Sample rate 51 200 Hz 1 3 octave band frequencies 12 5 Hz 20 kHz 824 Reference Manual 9 29 09 NOTE AC output gain matches the input gain setting 9 29 09 Prefilter Frequency Weightings A C and Flat Filter integrated response lt 0 15dB for all filters Real time operation lt 0 3 dB error for all filters tested with a swept sinusoidal input An
437. ng and Flat are measured to ANSI S1 4 and IEC 60651 standards for SLM linearity 1 3 octave filters listed are measured to the IEC 61260 standard for Class 0 linearity which is 0 3 dB The num bers in the table represent SPL levels with a typical 824 Reference Manual 9 29 09 377B41 microphone which has 44 1 mV Pa sensitivity Ly Percentiles Spectral AC DC Output 9 29 09 The System 824 Ly Centiles feature provides a display showing the six Ln values of one selected 1 3 octave filter It also displays spectra for the six Ln percentiles 3 Eb f de 55R L n1 f z Li amp T Lg 23 Li 67 41 5 46 5 41 5 5 50 0 35 5 LEB 7 j Lan n S 63566Hz Az ZzS 00 06 87 The AC DC output on the 824 is through the 3 5mm stereo connector at the bottom of the instrument This is a 2 channel output A mono plug should NOT be used it will short the ring signal to ground V DC Output Ring Ground Sleeve System 824 Virtual Instruments 6 5 Also take into account a gain of The two possible output signals are on the tip and the ring of the 3 5mm jack The sleeve is ground The selection in the 824 controls settings lists the signal output on the tip first followed by the signal output on the ring The AC output signal is always amplified or attenuated by the gain or attenuation selected for the instrument For example 1
438. ng screen appears 7 62 824 Reference Manual 9 29 09 When Set Mark is initiated by pressing the Check key a marker is placed into the time history record at that point in time 9 29 09 Mark 95 LAS Mark 1 gp Aircraft ag 1 1 The Mark display shows the current SPL level and a time history of the SPL level is shown graphically This enables you to set a marker in the time history To set a marker in the time history press the Check 0 key The following menu appears Set Mark EE cttam With Set Mark highlighted press the Check Y key to place a marker in the time history The Settings menu item in the Mark Check menu allows you to access the Settings menu in the marker area in order to change the marker descriptions The Graph menu item allows you to change the scaling of the Mark graph See below Using ID Setting Files 7 63 Graph Menu Graph Level may also be changed interactively with the Adjust Graph display below or W key allows you to adjust the Graph Level The 4 key allows you to adjust the Graph Scale When you are finished customizing the settings of the graph press the key to finish 7 64 There are two Graph settings available Menu Items Available Settings Options Graph Level 39 to 799 Graph Scale 2 1 1 2 1 4 1 8 The Graph Level setting allow you to
439. ng or short report Lowest Record 00000 Selects the lowest interval record to be printed Highest Record 65535 Selects the highest interval record to be printed Hist Report Yes You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time history record to be printed Highest Record 799999 Selects the highest time history record to be printed Histograms SPL Histogram Yes Prints SPL histogram and overall Spectral LN report Lowest Level 045 Selects the lowest SPL histogram level to be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 1 0 Selects the SPL histogram resolution Pk 1 Histogram Yes You can customize the Peak Histogram report by choosing the long or short report Lowest Level 110 Selects the lowest Peak1 histogram level to be printed Highest Level 140 Selects the highest Peak histogram level to be printed Resolution 1 0 Selects the Peakl histogram resolution Pk 2 Histogram Yes You can customize the Peak2 Histogram report by choosing the long or short report Lowest Level 070 Selects the lowest Peak2 histogram level to be printed Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 1 0 Selects the Peak2 histogram resolution Long Report Template LOG instrument
440. ng the Check key while in the Daily a or Daily b displays The Daily a display consists of 11 major components Display label Record Number Elapsed Time Date Reading LDN and CNEL Readings Maximum and Minimum levels e Peak level The Daily a display is shown below 824 Reference Manual 9 29 09 Display label Dai lu a Elapsed time 49 34 42 2244 Record Number Date Tue 13Jul1999 record is created eac Leq Reading Ley 58 new day LDN and CNEL Readings Gr 51 58 CHEL 51 1 Max and Min levels w 51 9 Min 24 1 Peak levels _ Pk i182 9dBH 183 2dBF The following explains each of the display s components Display label This shows the current display for example If the 824 is started at 1900 hours Record Number Each Daily record is shown in the the first Daily record will run from order that it occurred The record number indicates the order 1900 hours to 0000 hours and thena of the displayed Daily record in relation to the other records new day Daily record will begin A new daily record is created each new day A day is defined as 12 00 midnight to 12 00 midnight Elasped Time This shows the elapsed time of this day s measurement Date This shows the day date month and year for this record Leq Reading This shows the Leq for the day LDN Reading The
441. nload Filename Directory C Program Files Larson Davis 824 Utility Filename 05Jul1 6r sImdl Download For Help press F1 NUM 2 Selecting Active Measurements or Data Files There are two types of measurements that can be down loaded The first measurement in the list is the Active mea surement and is reported as Active Measurement on the tab of the download windows The other measurements are stored as Data Files on the 824 and will be reported as such on the tab of the download window 824 Utility Eile View Setups Data Help a AIE Show Files of Typs Meesurement 1 Active Measurement EY ALL tina z Ele View Setups Data Help Seup sinasca py al emm Tile SLM amp Analyzer a zr E 20 Data file i v StortTime 2000 411147142 mez es EndTime 2000 Jul 11 15 06 11 Show Files of Type lil 3 Loggia ALL binary z pai Tocsin Data File 3 logginglog ROOMS s 1 RT amp OA 2000 Ju 05161551 Note 2 2 2 1 2000 Jul 05 16 16 14 Size 7523 bytes GEARR 9 29 09 Using the 824 Utility Software 10 21 Downloading the Measurement The 824 Utility software has download a measurement first select the file type from multiple file download capability by pull down menu You may choo
442. nning and ending time in the 2 day timer mode Memory To access the Memory display use W key to select Memory from the Tools menu then press the Y key The following appears f Available memory as a percentage of total data Hemoru a memory 94 47 Available memory in bytes uugunqg Of 475149 bytes Number of various types of history records for a gt Logi given ID SSA in this example 9 29 09 Front Panel Keys Functions and Menus 3 27 For detailed information on the usage of memory e g bytes for each type of record stored see Memory Usage on page E 1 Only those records enabled for the active instrument type are displayed Available memory as a percentage of total data memory The Memory a display shows the amount of memory avail able for storing data This information is given both in bytes and as a percentage of the total memory that can be used for storing data This total memory does not include the memory allocated for ID registers In addition the Memory a display shows the number of pre viously stored records of various types for the active ID Pressing the D key again moves to the Memory b screen The following appears Henoru tb n Available memory in bytes Free 166 664 Total data files in memory Number of setup registers allocated for storing instrument definitions IDs of 2410233 bytes
443. ns previously described 3 20 The About a display shows the instrument s model number and serial number as well as the firmware revision number and date Pressing the D key moves to the About b screen The fol lowing appears The About b display shows the instrument s custom name and title fields printed on System 824 reports The fields are generally set to the owner s name and address The name is displayed at power on and printed on reports to customize them to your business To modify the About settings use or W key to select About from the Tools menu then press the key The About setting offers three Name fields and one Title field for use on System 824 reports Company Name Address Line 1 Address Line 2 There are three lines available for user specific data Each field 824 Reference Manual 9 29 09 Company name and address Customized by user Enter Company Enter Address Line 1 Enter Address Line 2 dD5ustem 824 About b User 0 Simple Integrating 5L m See the section Any Impulse Format on page 5 8 for optional Takt views 9 29 09 provides 30 alpha numeric characters and is used to describe the instrument or the organization to whom it belongs Title Like the Company Name field the Title field is capa ble of holding 30 alpha numeric characters It allows you to title the ID Instrument Definition you have created and to describe yo
444. nterface powers down gt Sent m gt Standby Timer 25 Communications GB mm Indicates 824 is ready to 4 receive commands r Indicates control ling device computer modem etc is This menu can also be accessed by pressing key on the communications display Use the right and left arrow keys to toggle between the Communication display and a list of Errors or Warn ing Messages These messages are useful when troubleshooting command problems The printer has its own baud rate for printing reports and is not affected by this setting 3 34 To access the Communication settings use or W key to select Communication from the Tools menu then press the key menu similar to the following appears Serial Comm Baud Rate t C 96001 Serial Address i188 Flow Control Baud Rate Speed at which the System 824 communicates with controlling devices computer modem etc through the serial port The baud rate has a range from 300 to 115200 baud 824 Reference Manual 9 29 09 Default is set to the value of the last 2 digits of the serial number and can be set within the range of 1 to 100 See the section Modem Control Mode All Instruments on page A 74 for more detailed information on modem communication 9 29 09 Baud Rate 1200 Bo j 2400 ess 192706 Il Serial Address Address of instru
445. ntifies the display which is the SSA Ln a display showing six Ln percent ages for an overall measurement Lns are reset with an Overall Reset Percentile values amp levels The Ln percentile levels level is that level which is exceeded percent of the measurement time By modifying the six settings you can select any six percentile values to be displayed at a time NOTE If Lns are enabled in the SSA Use the right D arrow key to view the SSA Ln b display instrument then the Back Erase feature is no longer available See the section Pause Back Erase on page 3 10 for information on the Back Erase feature Display label M9 5 5H Ln b Centiles m Current percentage shown by cursor 30 LOD pee Ln value as shown by cursor _ gt 75 2 i 555 Elapsed time 0 55 87 Ln graph The following is a brief description of each of the components of this display Display label The Display label identifies the display which is the SSA Ln b display showing Ln percentages 1 through 99 graphically for an overall measurement Use the amp and down W arrow Current percentage Selects of Ln to display 1 to keys to move from one percentile to 99 using the up and down W arrow keys to move another 5 20 from one percentile to another Ln This shows the current Ln value Elapsed time Shows the elapsed run t
446. nutes Off nn 523 ALL Auto Off Time nn 0 to 99 minutes S24 ALL Backlight Power Off Time nn 0 to 99 seconds S25 ALL Backlight On Off 526 ALL LCD Contrast 0 to 99 nn 527 SSA LOG TIMER MODE S28 SSA LOG TIMER RUN DATE 529 SSA LOG TIMER STOP DATE 830 SSA LOG TIMER RUN TIMEI 531 SSA LOG TIMER STOP TIME 1 832 SSA LOG TIMER RUN TIME 2 833 SSA LOG TIMER STOP TIME 2 834 ALL LOCK COMBINATION 835 ALL LOCK R S KEY 536 ALL LOCK SETUP 837 ALL LOCK FUNCTION S38 ALL LOCK RESET 839 ALL LOCK THE ON KEY A 38 824 Reference Manual 9 29 09 S40 ALL LOCK I O S41 ALL CAL LEVEL S42 ALL CALIBRATOR S N 843 LOG AUTO CALIBRATION MODE 844 LOG AUTO CAL TIME S45 SSA ISM DETECTOR LOG AUD 546 SSA ISM FREQUENCY WEIGHTING LOG AUD S48 ALL AC DC Output Control AC 1 AC 2 AC 1 DC AC 2 DC AC 2 AC 1 549 SSA ISM Pk Detector Weighting A C Flat LOG AUD 550 SSA ISM RANGE Normal Low High LOG S51 ALL Transducer Type Air Condenser Elec tret Direct 552 SSA ISM Simple SLM Displayed Value LOG AUD 853 SSA ISM CURRENT EXCHANGE RATE LOG 553 RTAf FILTER BANDWIDTH 1 1 1 3 OCTAVE 854 SSA ISM CURRENT THRESHOLD LOG S54 RTA RTAf DETECTOR LIN EXP TIME WEIGHTING S55 LOG CURRENT CRITERION S55 RTA LINEAR DETECTOR TIME SS SSS SECONDS 556 LOG OVERALL EXCHANGE RATE 9 29 09
447. o be used is described in the section TTools Key on page 3 18 subsection Calibration on page 3 22 under the heading Noise Floor 824 Reference Manual 9 29 09 Editing the Measurement Parameters NOTE If you recalling The design of the System 824 permits the simultaneous measurement ID which has already been measurement of the following sound level parameters a configured for the measurement you wish feature we call Any Data to perform then you can skip to the next section Live SPL Detectors Detectors Detectors A Y v v v v v v v v v v c Y v v v v v v v v v v Flat Y Y Y Y Y v v v v v v Note The detector used to create Peak Sound Pressure Level Loca with A C and Flat is a pure integrating true RMS weighting detector which integrates the energy over a specific period of time It Equivalent Continuous Sound Pressure Level Leq with be as short as 1 32 second in a time A C and Flat weighting A time history record can be history which be as long as 24 enabled to capture samples at periods as short as 1 8th of a hours As a result it does not include second decay artifacts of older instruments that integrate the output of the SLOW or FAST detectors 9 29 09 Performing a Sound Level Measurement 9 5 Sound Level Secondary Parameter Secondary Parameter Value Measurement Time 9 6 The SLM display is shown below Det
448. o displays which can be accessed by simply selecting Metrics with the Y Check key from within the main View menu then cycling through the views with the D and 4 arrow keys until the desired display appears The Metrics a display consists of five major components Display label Lg Reading DNL Reading CNEL Reading Elapsed Time The Metrics a display 1s shown below System 824 Views 5 65 Display label Hletr ics a Reading gt eq 64 CNEL Reading CHEL BA 51 46 A Elapsed Time Metrics b Display 5 66 The following explains each of the display s components Display label This shows the current display for example Metrics a Leq Reading This display shows the average level over the elasped time DNL Reading The DNL Day Night Average Sound Level display shows the equivalent sound level for the entire measurement period with a 10dB weighting applied to all sounds occurring between the times 22 00 and 07 00 CNEL Reading The CNEL Community Noise Equivalent Level display shows the equivalent sound level for the entire period with a 5dB weighting applied to all sounds occurring between the times 19 00 and 22 00 and a 10dB weighting applied to all sounds occurring between the times 22 00 and 07 00 Elapsed Time This shows the elapsed time of the overall measurement The Metrics b display con
449. o have an essentially flat frequency response when in a space relatively free of reflections and when pointed at the source of the sound Random incidence The microphone has been adjusted to have an essentially flat frequency response for sound waves impinging on the microphone from all directions Pressure The microphone has not been adjusted to have an essentially flat frequency response for sound waves impinging on the microphone from all directions What a microphone measures 4 microphone detects more than just sound The motion of a microphone diaphragm is in response to a force acting on it The force can be caused by a number of sources only one of which are we interested sound Non sound forces are 1 direct physical contact such as that with a finger or a raindrop 2 those caused by the movement of air over the diaphragm such as environmental wind or blowing 3 those caused by vibration of the microphone housing and 4 those caused by strong electrostatic fields Rules 1 Do not permit any solid or liquid to touch the microphone diaphragm Keep a protective grid over the diaphragm 2 Do not blow on a microphone and use a wind screen over the microphone to reduce the effect of wind noise 3 Mount microphones so their body is not subject to vibration particularly in direction at right angles to the plane of the diaphragm 4 Keep microphones away from strong electrical fields A microphone measures forces not press
450. odel and serial numbers for your instrument pre amplifier and microphone in the spaces provided on the copyright page near the beginning of this manual You will find the instrument s Model Serial numbers printed on the label on the instrument s back panel The microphone s Model Serial numbers are located on the inside ring of the microphone The pre amplifier s Model Serial numbers are engraved the outside surface You may be asked to provide this information during any future communications with Larson Davis Inc 824 Reference Manual 9 29 09 181195 loAIoosuem TETTE SA irpeq 41914 TSAO prnbrT orydein mo Od OV 105892014 8081 reusiq Tepuo eo pue xoo o eum eos 181195 WOY Ysea lossooo1douonAl uornoojeq Kouenboiq Sseq ugSIH ZH 01 20 1 0 IM V TA rensa o Sopeuv ssed ZH 01 10 14 0 IMV 2814 aN 9 C T WVA Jo1I9AUO So euy gp 05 0 gp 05 uIo S S 79 0 O I 09u00 jddng 10500 JoMOq Figure 1 6 System Diagram 1 15 Introduction 9 29 09 Comments concerning the Digital Signal Processor If the System 824 is not being used for long periods of time 1 month or more it is recommended that the batteries be removed to avoid damage to the instrument Although the System 824 does have analog
451. oise Dose D D 16 Background The all encompassing sound at a given location caused by all sources of sound but excluding the source to be measured It is essentially the sound that interferes with a measurement Pink It is a random sound that maintains constant energy per octave Pink light 1s similar to pink noise in that it has a higher level at the lower frequencies red end of the spectrum White It 1s a random sound that contains equal energy at each frequency In this respect it is similar to white light It is the percentage of time a person is exposed to noise that is potentially damaging to hearing Zero represents no exposure and 100 or more represents complete exposure It 18 calculated by dividing the actual time of exposure by the allowed time of exposure The allowed time of exposure is determined by the Criterion Duration and by the sound level the higher the level the shorter the allowed time The sound levels must be measured with A frequency weighting and slow exponential time weighting See Projected Noise Dose _ 1007 0 12 4 D 0 where T is Measurement Duration is Criteria Time L is TWA L is Criteria Level q is exchange rate factor see page D 8 Exchange Rate Q Exchange Rate Factor q Exposure Factor k Standard ANSI 12 19 824 Reference Manual 9 29 09 Noise Exposure OSHA Level LosuA Preamplifier Projected Noise Dose Single Event Noise Exposure Lev
452. ommand syntax to program each desired read variable and its position in the macro Syntax Response G roup n var no lt cr gt lt lf gt Example G1 4 lt cr gt assigns the current SPL to the first group option Example G2 15 lt cr gt assigns Lmin to the second option Example G3 19 lt cr gt assigns Lmax to the third option Example G4 0 lt cr gt terminates group command programming 9 29 09 29 Where n is from 1 to 8 indicating the macro position and var no is the number of the R variable associated with the position Use a var no of 0 to define the last position when less than eight are desired After programming this group read list the response to GO 1s 59 5 38 6 102 2 the SPL Lmin and L min max Setting Commands The Settings select what functions are enabled and determine how the measurements performed Settings can be both set S and queried Q The setting numbers provided below in the Setting List section are for both the Set S and Query Q commands A 30 Option e g Sun Mon Tues Sat Numeric e g 123 45 e Character e g Gas Flare Test 1 can be up to 30 char acters Template e g hh mm ss 824 Reference Manual 9 29 09 Brackets indicate optional characters or operands cr carriage return lf line feed space Querying Settings The current setting is retri
453. ong measurement time can consume a large amount of data memory 824 Reference Manual 9 29 09 Use the W keys to move from one setting to the next Then use the D key to change the selected setting The 4 key is used to return to previous menus 9 29 09 The following tables show the Time History settings for the LOG and SSA instruments Each setting is described later in greater detail Menu Items LOG instrument Available Settings Options Hist Enable No Yes Hist Period 110255 Period Units 1 32s 1 0s 10 0s 60 0s Other Level None Pk II Pk I Lmax Advc See Adv TH Resolution 0 1 dB 1 0 dB Adv TH Activates a set of 3 displays used to configure what time history data will be stored See page 7 26 Marker Text Marker 1 Aircraft Marker 2 Automobile Marker 3 Truck Marker 4 Train Marker 5 Animal Using ID Setting Files 7 31 Menu Items SSA instrument Available Settings Options Hist Enable No Yes Hist Period 110255 Period Units 1 32s 1 0s 10 0s 60 0s Resolution 0 1 dB 1 0 dB TH Setup Activates a set of 3 displays used to configure what time history data will be stored See Advanced Time History LOG SSA on page 7 35 Marker Text Marker 1 Aircraft Marker 2 Automobile Marker 3 Truck Marker 4 Tra
454. only Yes Start Level 0 99 dB Ln 1 Percent 0 00 to 99 99 Ln 2 Percent 0 00 to 99 99 Ln 3 Percent 0 00 to 99 99 Ln 4 Percent 0 00 to 99 99 Ln 5 Percent 0 00 to 99 99 Ln 6 Percent 0 00 to 99 99 Spectral Ln SSA None only Overall Interval NOTE Interval Spectral LNs will not be available when R I Correction is turned on This function turns on or off the automatic storage of the six Ln percentile levels for the overall measurement No The six Ln levels are not stored for the over all measurement Yes The six Ln levels are stored for the overall measurement The Start Level allows you to set the minimum decibel level to be included in the statistical histogram and calculated Ln Percentiles Using ID Setting Files 7 21 Ln s Example The Ly Centiles set the six percentile values to be measured logged if selected and shown in the Ln displays Using these six settings you can select any six percentile values As shown above these settings can each take on any value within the following range 0 00 to 99 99 Whenever you change any percentile value the instrument sorts and reorders the percentile values into ascending order as demonstrated in the following example Suppose you change L 3 from 30 0 to 5 0 The original setting val ues will then be automatically sorted into ascending order and reas signed as shown in the table below Spectral Ln s SSA only Spectral Lns
455. ont Mark 22 Keu ih ED Rutamble Identifies the Marker 5 42 824 Reference Manual The following explains the display s components Display label This shows the current display for example SLM Time History Status Indicator The Status Indicator will show one of the three possible events that occurred in the point of time referenced by the Time Cursor Run Indicates a measurement started at this time Stop Indicates a measurement stopped at this time 9 29 09 See the section Other Level LOG only on page 7 33 for additional details Single Other Level Multiple Other Levels 9 29 09 Pause Indicates the measurement paused at this time Cont Indicates the measurement continued at this time Mark Indicates a marker was set at this point in time Time Cursor The Time Cursor the vertical bar allows you to scroll graphically through the history of the displayed measurement readings using the and arrow keys The Time History display s Status Indicator will show what event took place at the point in time associated with the Time Cursor s current position Other level A wide range of different parameters can be displayed in this window depending upon the setup procedure utilized The simplest situation is when the user selects to display a single alternative sound level parameter Pk I or Lmax which is setup directly using the Other Lev
456. ories etc To access this sub menu highlight Customize and press the D key Customize unterm re Hol 824 Reference Manual 9 29 09 Quick Start The System 824 instrument provides simultaneous measure ments of sound pressure level using Fast Slow Impulse Peak and Leq detectors with A C and Flat weighting cover ing a large dynamic range of greater than 105 dB in the LOG and ISM instrument and 80 dB in SSA instrument With the System 824 calibrated the desired instrument definition selected and its associated settings properly configured you can easily take a measurement and examine the readings from the data collected Taking an actual measurement with the System 824 is as easy as pressing the 8 RUN STOP key This chapter helps users begin using the System 824 immediately This chapter will present the following Turning on and Calibrating the System 824 Taking Measurements and Storing Data e Recalling Stored Data Deleting Stored Data Selecting and Modifying Instrument Definitions IDs Turning On and Calibrating the System 824 This section guides you through the process of turning on and calibrating the System 824 9 29 09 Quick Start 4 1 This screen displays three lines of user information which may be defined as name and address settings You can use the 824 Utility Software to input this information This display also shows the serial number of the instrument a
457. orm Ration of Value to Reference Peponential Fomor T Exponen Ratio 1 10 0 10 10 10 100 10 20 200 10 23 1 000 10 30 10 000 10 40 100 000 10 50 1000 000 10 60 Each time the sound pressure level increases by 6 dB the corresponding sound pressure value is doubled and thus multiplied by 2 Each time the sound power level increases by 3 dB the sound power value is multiplied by 2 Thus it is important to notice that a doubling of the sound power is equal to 3 dB and a doubling of the sound pressure is equal to 6 dB since a doubling of the sound pressure will result in a quadruple increase of the sound power The advantage with using dB is simply that they remain the same even if we use sound pressure or sound power Compare this to the use of voltage and power units in electrical engineering units being related by P V In table 2 an illustration is made of values calculated on sound pressure non squared units The original definition of decibel was intended for power like quantities such as sound power If we consider sound pressure levels instead usually denoted P in acoustics the 824 Reference Manual 9 29 09 equation will be the same since the two in the squared units will move from within the bracket and become a 20 log instead of a 0 log and thus compensate for using linear or quadratic units Please note that it is not allowed to use 20 log for squared units since that expression assumes
458. ould be a measurement where data 1s gathered in one hour time intervals over a 24 hour period The SSA instrument has 4 unique interval displays which show the Max spectra at the time the broadband level was at maximum Min spectra which is a bin by bin minimum the Leq or average of each frequency over the interval period and Leq By Time which shows the level for each frequency from each interval record over time System 824 Views 5 13 The following are examples of the interval displays Leu nes 14 33 DH if 4 42 41 00 10 00 Interval period Time of interval The Leq display shows the average level for each filter during the interval period lax 14 23 DH iBBBHz 228 The Max display shows the spectrum correspond ing to the maximum broadband level during the interval period Wm Leg By Time RECORD 2H 56 em na dBi an 15 13 2060 rl gHz lla 00 01 00 The cursor shows the level for the interval record selected m Hi p mined 15 06 08 2 32 9 im immmHz oo ao o0 1 The Min display shows the bin by bin minimum level for the interval period L The up and down arrow keys change the frequency displayed Do the following to ensure you have Spectral Lns for the interval period Go to the Edit Settings menu for the SSA instrument SL
459. ound occur during the measurement such as a door slam you can pause the instrument cursor to the left with the 4 key to a time prior to the unwanted event and press the fl key once more to recommence measurement from that point erasing the data to the right of the cursor This is the Back Erase feature as indicated on the display when the Il key had been initially pressed Changing the detector of the displayed SPL value 2 8 You can change the parameters being displayed in the View window while a measurement is in progress without going to the Setup menu 824 Reference Manual 9 29 09 Step 1 change to the detector type use the amp 5 keys to highlight the Slow detector as shown below SLM SPL e 3b A inn L BD e Sd odgn un Bain 0 Step 2 To scroll through the optional detectors press the 4 arrow keys This will display the SPL corresponding to the Fast and Impulse detectors Go back to the Slow detector and press the check key or wait several seconds until the highlight disappears Changing the frequency weighting of the displayed SPL value Step 1 To select the frequency weighting parameter press the W keys to highlight the A weighting as shown SLM RTA SPL Leg 2dBA Gain 8 Step 2 Use the D or 4 arrow keys to display the weighted or Flat weighted SPL corresponding to the Slow detector 9 29 09 Overview 2 9
460. ove this threshold contributing to the measurement The titles for the measurements are designed to indicate the current exchange rate in force Leg is used to designate TWAs based upon 3dB exchange rate Lpop for United States Department of Defence is used to designate TWAs based upon a 4dB exchange rate Losna for the United States Occupational Safety and Health Association is used to designate TWAs based upon a 5dB exchange rate Layo for average is used to designate TWAs based upon a 6dB exchange rate No attempt is made to meet the IEC 804 requirement to title the TWA by frequency weighting and time interval within the analyzer s display or report system It 1s represented 824 Reference Manual 9 29 09 though by placing the weighting designation following the dB units indication associated with the numerical output The actual measurement time is also provided for each TWA value to fulfil the time interval description requirements For example the System 824 s Logging SLM Overall a dis play shows the current SPL Sound Pressure Level in 1 10th decibel dB resolution The actual real time resolution is 1 320ddB The displayed SPL is followed by the text dB and then the frequency weighting in effect set to A in this example Scrolling SPL history Current SPL while running or at the time a stop occurred The currently selected frequency weighting for SPL Th
461. owing appears Current time Time a Current day of the week and date 15 18 52 The time of the next timer function gt Sat H6Deci997 gt Next action mu he Clock Timer Settings be changed by pressing the T key from the Clock Timer display screen The or clock display shows the current time day of the week date and the time of the next timer action Pressing the D key again moves to the Time b screen The following appears The Time b or timer display shows the current timer pro gramming including the mode and the appropriate run and stop times and dates To modify the Clock Timer settings use the or W key to select Clock Timer from the Tools menu then press 9 29 09 Front Panel Keys Functions and Menus 3 23 Time b The currently selected timer mode Timer Mode Oft AE Spas gt 1997 to 21 1999 The first run and stop times From 5 88 to Hest action mau miu The time of the next timer function 2 the D key A screen similar to the following will appear Clock Tiner Current Ti d 15 1280 1523 current bate 12 66 97 Da Heek The clock in the 824 uses a 24 hour format with hours 0 through 11 being a m and hours 12 through 23 With the Clock Timer menu you set the instru
462. phical display for that particular frequency Press W arrow key to change to the RTA Leq view screen similar to the following appears SLH R TH Ley 65 1npg fefe Buy BO n8 ree d E RE 1888Hz Mia 00 55 25 Use the D and 4 arrow keys to change the selected frequency As the frequency is changed the Leq for that frequency will be displayed in the upper left corner Additionally the cursor bar will move along the graph to the position that corresponds to the Leq graphical display for that particular frequency Press W arrow key to change to the RTA Max view screen similar to the following appears Quick Start 4 9 The RTA Max view shows a graphical display of the Live spectrum of the maximum broadband level since the last current reset SLA RTA Step 8 Use the D and 4 arrow keys to change the frequency level being displayed Step 9 Press the W arrow key to change to the RTA Min view A screen similar to the following appears SLH R TH 5 ian 36 7 m Step 10 Use amp and 5 arrow keys if you want to move back and forth between the different RTA screens Step 11 Press the RUN STOP S key to stop the current reading If you attempt to store data while a Step 12 Press the Il Data key Select Store Data and measurement is still running a press the key to store the measurement s data wa
463. played press the right arrow to manually lock the filter so that it does not change when measuring low amplitudes AGC is not active in the manual unlock or lock modes For automatic operations select the auto mode by pressing the left or right arrow key until the diamond icon appears A trigger level setting is found on the check menu that defines the amplitude below which the lock is set When above the trigger level the filter frequency will track the highest amplitude signal When the level of that filter drops below the trigger level the lock is activated and the filter frequency is unchanged The icons will show this condition with the lock and diamond icons Note To change to another filter in auto mode just increase the amplitude until the level is above the trigger level When in automatic mode the Automatic Gain Control will be activated When the gain is set to OdB it will be changed to 30dB when the signal is more than 45dB below the overload level for 1 5 seconds When the gain is set to 824 Reference Manual 9 29 09 Linearity FFT Check Menu 9 29 09 30dB the gain will be changed to OdB whenever the instrument becomes overloaded or the level is within 8dB of the overload level for 1 5 seconds The instrument will beep once when the gain is changed automatically to OdB and twice when it is automatically changed to 30dB Press the check key to open the Linearity FFT check menu shown below Set Reference
464. ple 0 to 5 volt Yes The Logic Input line on the control connector at the base of the 824 can be set to control the Run Stop of the instrument This input takes a zero to five volt digital signal and performs the function selected by the Logic In setting found in the Controls menu SETUP gt Edit Settings gt Controls gt Logic In When set to Toggle it works just like the Run Stop key You can connect a momentary push button switch from the five volt wind direction power pin 6 to the logic input control line pin 3 When set to Level it forces the unit to be in run mode when the logic input is high 5 Volts and forces a stop when it is low 0 Volts You can connect a toggle switch from the wind direction power pin 6 to the Logic Input pin 3 the 824 will run when the switch is ON and be stopped when the switch 1s off Note The Level setting will override the Run 824 Reference Manual 9 29 09 Question 10 Answer 9 29 09 Stop key on the instrument and the M3 amp 4 I O commands The 9 PIN Miniature DIN connector needed can be purchased at www digikey com as P N CP 2090 ND What is the key sequence to perform a User Reset By holding down the RESET the CHECK and the POWER keys simultaneously to turn the 824 on will activate a User Reset This User Reset will perform a complete memory test reset all data erase all user setup IDs Instrument Definition or setup file and recall from EEPROM one SSA one L
465. plication You can of course create new setups for particular applications and add your own IDs to the System 824 The SLM amp RTA SSA Logging LOG and Integrating SLM ISM instruments are available in various 824 configurations The table on the next page explains each of these instruments and shows the configuration in which it is available The following configurations of the System 824 are available 8248 824A 824L 824 The following options are also available 824 RTA 824 FFT 824 AUD 824 TAL 9 29 09 System 824 Virtual Instruments 6 1 The table below configuration Instrument ISM Integrating SLM measures LEQ SEL Min Peak with all weights A C Flat and with all detectors slow fast and impulse simultaneously Includes a high and low measuring range 8245 824L describes the basic functions of each 824 RTA 824 FFT 824 AUD 824 824 TAL SSA Sound spectrum analyzer measures LEQ SEL Min Max Peak with all weights A C Flat and with all detectors slow fast impulse peak and Leq simultaneously plus 1 1 and 1 3 octave data stored in time and interval histories at storage rates as fast as 8 times per second Included are Ln data showing 6 Ln values a graph of L1 through L99 broadband and spectral Lns Wind and Tach data with external transducers LOG Logging SLM measures LEQ SEL TWA Min Max Peak with all weights A C
466. power and flexibility of the System 824 gives you a variety of measurement possibilities The System 824 has a number of distinct setups or Instrument Definitions ID from which you can select the one best suited for a particular application You can of course modify any instrument definition for another application and add it to the existing list of instrument definitions An ID name consists of an eight character name followed by a three character extension called the Instrument Type Some IDs presently available are SLM amp RTA SSA SLM ISM and Logging LOG The complete ID consists of its name and an instrument setup based on one of the available Instrument Types There are a number of factory supplied setups available for use by the user In order to create a new setup modify an existing ID and store it under a different name as a new setup The Instrument Type will remain the same as that of the ID used to create it Thus a new setup created for the measurement of environmental noise by modifying the Logging LOG ID might become ENV LOG Overview 2 1 Instrument Definition ID Types Write Protect Delete Write Enable IDs SLM amp RTA SSA 2 2 Instrument Definition ID SLM amp RTA SSA Logging LOG SLM ISM SLM Range dBA 80 105 105 Real time Spectrum 1 1 and 1 3 octave No No Analysis bandwidths Manual Data Storage Yes Yes Yes Back Erase Yes No Yes Automatic Data Time History
467. prised of 100 samples it will be averaged as one record Rooms Views NCB and RC are calculated and displayed from any spectral display including snapshot or Averaged Spectrum and are accessed from their individual check menus 9 29 09 The check menu offers the following options Edit Note Edit the note of this stored record Locate Locate a Spatial Avg history record First The first Spatial Avg history record Last The last Spatial Average history record Find Finds the specified Spatial Average his tory record Average Add spectrum to spatial average Rooms View Room Criteria for this spectrum View Back Return to the previous display Graph Adjusts the vertical graph scale and offset The Rooms Views are accessed from the check menu of every display that can show a spectrum The Rooms displays consist of RC NCB and HTL All these measurements are based on ANSI S12 2 1995 The NCB and RC Criteria for 1 1 octave data calculates the following SIL speech interference level Pass Fail on Rumble check Pass Fail on Hiss check Mid frequency average Lmf and RC Neutral Hiss Rumble or Vibration Rumble check RTA optional 11 39 NCB and RC are only displayed when using 1 1 octave filters RC NCB and HTL are accessed in the Rooms from any spectrum s check menu display Rooms NCB The Rooms NCB display calculates the noise criterion for the spectrum being displayed when Room
468. ption receive the command 0 Address 0 80 Broadcast will enable addressing of all 824s on the net in a broadcast receive mode Only the 824 with address 1 will respond all will the net Useful when only one device is connected 127 Address 127 FF Address All will enable all 824s to receive and respond to commands in other words it will disable the addressing feature of all 824s on 126 Address 126 FE Disable All will disable all 824s and none will respond to commands received This is useful when trying to communicate with one device on the net that has addressing disabled by having its address set to zero 125 Address 125 FD Lock will lock the current addressing of all 824s on the net so that binary setting data may be sent to the currently addressed 824 To cancel the lock so that addressing may be changed a lt break gt is sent A 6 824 Reference Manual 9 29 09 124 Address 124 SFC Auto ID will initiate an Auto Identification of all 824s on the net using a timing scheme based on each unit s address The data received will be the address byte from every device on the net delayed by 10mS times the address thus it will take a maximum of 1 second to receive the byte from unit 100 break A short break will cancel the addressing lock initiated with the 125 address com mand so that addressing may be changed break Two breaks in a row will re initialize the I O
469. put Ring Ground Figure 1 5 AC DC output connector Preamplifier Input Connector Pin 1 N C Pin 6 Positive Supply 28 VDC Pin 2 Signal Ground Pin 3 Mic Bias Voltage Pin 5 Reserved Pin 4 Signal Pin 7 Negative Supply 0 VDC System Diagram 9 29 09 The preamplifier input connector accepts the PRM902 preamp Figure 1 6 illustrates the acoustic to digital signal path in the System 824 As you can see incoming sound is first converted to an electrical signal by the microphone This electrical signal is amplified filtered and then sampled by an analog to digital converter ADC The processor then Introduction 1 13 Getting Started Unpacking and Inspection 1 14 calculates all of the desired data based on the sampled data sample rate of 48 51 2 kHz This section outlines the steps to unpack the System 824 The following topics are covered Unpacking and Inspection Accessories and Optional Equipment Connecting Internal or External Power Environmental Considerations You will then be ready to use the System 824 for actual measurements Your System 824 has been shipped in protective packaging Please verify the package contains the items listed below Retain the packaging for safe shipment for calibration service Report any damage or shortage immediately to Larson Davis Inc at 801 375 0177 If you have not already done so please record the purchase date the m
470. puter Step 1 With the instrument turned off insert the cable using CBL006 connector in the instrument s 8 pin port Step 2 Connect the CBL006 cable to the serial port of the computer using the supplied 9 to 25 pin adapter as necessary Pin configurations for the CBL006 824 8 pin Connector End Computer 9 pin RS 232 Connector End Pin 1 Handshake Out Pin 6 DataSetReady Pin 8 Clear to Sent Pin 2 Handshake In Pin 4 Data Terminal Ready Pin 3 Transmitted Data Pin 2 Receive Data Pin 4 Ground Pin 5 Ground Pin 5 Received Data Pin 3 Send Data Pin 6 Transmitted Data No Connection Pin 7 Com Extra Input No Connection Pin 8 Received Data Pin 5 Ground Note that the pin configurations for the newer thin CBL006 with the wrap around label are slightly different as 9 29 09 A 3 shown below Both versions work properly with the Model 824 Early thick cable CBLOUE Newer thin CBLOO6 0544 NC 1 NE 4 5 d CI CIT Be CAO dh 4 J n 8 CD OO 824 Reference Manual 9 29 09 Daisy Chain Addressing The following instruments compatible on a common network Models 712 720 812 814 824 870 and 100 Future instruments may also be compatible with this network A network of instruments may be interconnected to one computer using the appropriate cabling and each may be controlled individually Each is given a unique address By default all 824s
471. r Indicates that the external power source is not a battery If the external voltage is less than the internal battery voltage then the internal batteries will supply power for the instrument Battery Indicates that the external power source is a battery which should not be allowed to deep dis charge Min Battery 0 to 15 9 10 8 volts Sets the external cutoff voltage when a battery is is the default setting used for external power 10 8 volts DC is the recom mended setting for a 12 volt battery Extra Notes on Power Conservation NOTE To exit the Power display press the left arrow key or use the view key to the select desired view WARNING WARNING WARNING Run Stop Key 3 8 If you are using an external power supply the key will display the constant voltage coming from the power supply If the external battery supply ever drops below 10 8 Volts set by the Min Battery setting the 824 will automatically turn off Discharging some types of batteries such as lead acid deeply will greatly shorten their service life For detailed information on the use of external power see Power Current Draw of 824 Using External Power on page C 49 Battery life is reduced by approximately 25 with the back light on Loss of power may cause loss of memory Turn off power to change the microphone or preamplifier Sensitive electronics can be damaged by voltage spikes Use the 8 RUN STOP k
472. r Measurement Navigation and Control These keys are covered in the following order in this chapter 9 29 09 Front Panel Keys Functions and Menus 3 1 Power Key Turns on off the System 824 accesses bat POWER tery power monitoring and LCD utilities and is used to close menus Measurement Keys en RUN STOP Begins and ends measurements D PAUSE Pauses readings while running Previews current SPL when stopped Activates Back Erase function RESET Displays Reset options menu Current Overall Options Navigation Keys 9 ARROW Used to move through System 824 menus change settings and scroll through data displays The key exits menu s SELECT Selects highlighted menu items like a button on a mouse concludes data entry like the Enter key on a PC keyboard and activates context specific menus called Check menus Control Keys VIEW Displays View menu choices where you can select which data to view DATA Displays the Data Files menu This menu is used to store and recall Data Files 3 2 824 Reference Manual 9 29 09 NOTE The reference information in this chapter is organized according to func tions rather than by tasks which can use several functions Power Key e Displays the Setup menu Allows you to SETUP view and edit the settings for the active
473. r Level setting is set to Advc to enable the advanced time history Time History Variables SSA LOG TAL Brackets in the syntax indicate optional characters and operands Syntax Response H istory var no time var H2 123 4 Peak level in current record Leq RMS Level nnn n dB H2 Peak Level nnn n dB H3 Run Time of Sample calc hhhhh mm hh mm ss mm ss ss H4 HISTORY BARGRAPH Histogram Table Variables Brackets in the syntax indicate optional characters and operands Table e 1 RMS e 2 Peak 3 Unweighted Peak Default is last used table or RMS Syntax Response A 68 824 Reference Manual 9 29 09 T able var no table table var Example T1 1 75 0 RMS current bin level T 1 n LOG Level of current bin nnn n dB T2 n LOG Count of samples nnnnnc c K or M for Kilo or Mega T3 n LOG Percent of total nnn nn96 T5 n LOG Prints the accumulated time for the hhhhh mm ss s current level bin The table number 18 optional T n 64 LOG Shows total of bins less than this level T LOG Shows total of bins greater than this n 128 level plus resolution a Where n equals the table number 1 RMS 2 Peak amp 3 UnWeighted Peak Print Command Brackets in the syntax indicate optional characters cr carriage return lt l gt line
474. r and a Model 377B41 free field microphone with and without a windscreen This data include the effects of reflections and diffraction m Expanded 0 0 Windscreen on Free Field Effect of uncertainty FreeField Field 824 Corrections Frequency Hz 1 Windscreen s 2 Response Correctons 0 Free Field with Wind dB dB Screen on 824 Corrections dB 095 dB 251 19 0 0 0 0 0 0 0 0 0 0 0 25 316 23 0 0 0 0 0 0 0 0 0 0 0 25 398 11 0 0 0 0 0 0 0 0 0 0 0 25 501 19 0 0 0 0 0 0 0 0 0 0 0 25 630 96 0 0 0 0 0 0 0 0 0 0 0 25 794 33 0 0 0 0 0 0 0 0 0 0 0 25 1000 00 0 0 0 0 0 0 0 0 0 0 0 25 1059 25 0 0 0 0 0 0 0 0 0 0 0 25 1122 02 0 1 0 1 0 1 0 1 0 1 0 25 1188 50 0 1 0 1 0 0 0 1 0 1 0 25 1258 93 0 1 0 1 0 0 0 1 0 1 0 25 1333 52 0 2 0 2 0 1 0 3 0 3 0 25 1412 54 0 2 0 2 0 1 0 3 0 3 0 25 1496 24 0 2 0 2 0 1 0 3 0 3 0 25 1584 89 0 2 0 2 0 2 0 3 0 3 0 25 1678 80 0 2 0 2 0 1 0 3 0 3 0 25 1778 28 0 2 0 2 0 2 0 0 0 0 0 25 1883 65 0 2 0 2 0 2 0 1 0 0 0 25 1995 26 0 3 0 3 0 2 0 1 0 1 0 30 2113 49 0 1 0 1 0 3 0 3 0 3 0 30 2238 72 0 1 0 1 0 3 0 4 0 4 0 30 2371 37 0 3 0 3 0 3 0 6 0 6 0 30 2511 89 0 2 0 2 0 3 0 5 0 5 0 30 2660 73 0 2 0 2 0 3 0 5 0 5 0 30 2818 38 0 1 0 1 0 3 0 4 0 4 0 30 2985 38 0 1 0 1 0 3 0 4 0 4 0 30 3162 28 0 1 0 1 0 2 0 1 0 1 0 30
475. rammable Run Stop timer for automatic measurements AC DC outputs to recorder Field upgradable firmware keeps instrument current with the latest features via ROM disk upgrades Two year limited warranty General Specifications Reference level 114 0 dB SPL Reference level range ISM Mode Normal SSA Mode 0 dB Gain Reference frequency 1000 Hz Reference direction 0 for a free field microphone and 80 for a random incidence microphone Temperature lt 0 5 dB error between 10 C and 50 C Storage temperature 10 C to 60 C Humidty lt 0 5 dB error between 30 and 9096 relative humidity at 40 Equivalent mic 18 pF for Larson Davis impedance 1 2 microphone lt 30 1 dB relative to the reference range Range level error Calibration procedure Using a Larson Davis CAL200 or equivalent calibrator insert the microphone fully into the calibrator Set the calibrator to 114 dB SPL On the 824 press the tools key arrow down to Calibration and press the right arrow key From the calibration menu use the down arrow W key and highlight Change Press the check key to initiate the calibration The 824 will prompt you to turn the calibrator on with Calibrator Active Select Yes after turning the calibrator on and press the check key The 824 performs the calibration change Effect of Magnetic Field 80 A m 1 Gauss 60 H
476. re record With this feature turned off and the Autostore function turned on the 824 will only store Leq Max and Min spectra Triggering Turns triggering on or off There are four parts to triggering Arm Trigger End and Then Arm and Trigger work in tandem to create a two step trigger to start an Autostore End and Then work together to determine when to stop measuring Trigger Source Allows the user to select a filter or flat overall level as a trigger source Arm Mode The 824 becomes armed when the following conditions are met Now The 824 will arm immediately e L lt When the level is less than the Arm Level for the Arm Time then the 824 will arm e L When the level is equal to the Arm Level 0 5 dB for Arm Time then the 824 will arm e L gt When the level is greater than the Arm Level for Arm Time then the 824 will arm Input The 824 arms when the logic input line changes to Arm Logic In state optional 11 9 Arm Time is used in conjunction with Arm Level as a qualifier for the level setting See example below 11 10 Time 824 arms after the Arm Time seconds in the ready mode Count 824 arms after Arm Count samples of data have been received Arm Level This trigger level is used when the Arm Mode is set to a level state L lt L L gt This level must be reached before the 824 will arm 0 0 255 9
477. rees 0 360 Settings on Percent 0 100 page 7 25 Volts 0 2 49 Number 0 255 93 Thisisan Wind Tach No optional Yes feature Windy Threshold 0 0 65 535 the Level firmware 824 WND Windy Exceedance 0 0 65 535 Level Windy Hystereses 0 0 65 535 Windy Pause Enable No Yes Pulse Trigger Voltage 0 0 2 5 Pulse Source Int Ext Define Data Report No Report Yes Setup Report No Yes 824 Reference Manual 9 29 09 Menu Items Define Report Continued Submenu SPL Histogram Available Settings Options No Yes Pk I Histogram No Check Menus 9 29 09 Yes Pk II Histogram No Yes Interval Report No Short Long History Report No Exceedance Report No Short Long Daily Report No Short Long In addition to being able to modify an instrument ID s settings through the Edit Settings item in the Setup menu selected settings can also be modified through what 18 known as a Check menu which is specific to the current display function The Check menu is accessed simply by pressing the Check key from within the System 824 s different views The available Check menu options vary between an instrument ID s different views The options available from each display allows the user to change settings peculiar to that display function In many cases they are shortcuts to other displays In some cases the check menu allows you to Using
478. rement data and is reset when the overall Using ID Setting Files 7 23 PK Excd Lvl 1 LOG SSA NOTE The data for this comes from the instantaneous peak level selected by the Weight setting Pk Excd Lvl 2 LOG SSA Hysteresis LOG SSA 7 24 measurement is reset A special flag is set with all exceedance records whose Lmax is greater that this level This setting can take on any integer value within the following range 0 to 255 dB The Pk Excd Lvl 1 sets the trigger level for the primary peak detector Pk I When the primary peak detector level exceeds this threshold the corresponding Pk I exceedance count is incremented once You can view this count on the Stats b display This count is associated with the overall measurement data and is reset when the overall measurement is reset This setting can include any integer value within the following range 0 to 255 dB Pk Excd Lvl 2 sets the trigger level for the secondary peak detector Pk II When the secondary peak detector level exceeds this threshold the corresponding exceedance count is incremented once You can view this count on the Stats b display This count is associated with the overall measurement data and is reset when the overall measurement is reset This setting can include any integer value within the following range 0 to 255dB To prevent multiple triggering counting of the same event a hysteresis value may be entered
479. rent battery type and charger status Battery Source EXT Battery 1 12 30 Battery 3 66 25 4 F Hlkaline Described later in greater detail Charge Activates the smart battery charger Type The charge mode will be activated automatically when external power is applied and the battery is at 75 capacity or less WARNING 3 6 Select Alkaline or NiMH for individual cells See Connecting Internal or External Power on page 1 18 Once the smart charger has been activated the 824 will not allow you to shut it off when the power key is held down The 824 will beep and give the warning Charging Battery Please Wait Simply press the power key again to force the 824 to shut off Whenever external power is applied the 824 will trickle charge to keep the battery pack at full charge The 824 must have external power applied and be left ON in order for the battery pack to charge 824 Reference Manual 9 29 09 The power Settings menu item provides the following eight settings Menu Items Available Setting Options Description Power Off Mode Blank LCD Auto Off Manual Off Blank LCD The instrument LCD display and serial communication port will turn off after the keyboard and serial port have been inactive for the period of time set by the Standby Time setting Auto Off If the instrument is stopped with no reports printing and
480. ress the File folder button next to the Directory entry NOTE The 824 Utility program will download the files with the date the file was created as the file name as a default It will also download the file to the 824 Utility Folder as a default The option to specify a file name and destination folder is an optional selection and is not necessary for download A standard Windows file selection dialog box will appear Select the destination directory you wish Select or Enter a file to store measurement during download sew Desktop E 3 Floppy amp Drive C CJ Program Files Larson Davis e i Network Neighborhood 085 21 SLMDL slmdl Download File 9 29 09 Using the 824 Utility Software 10 19 Changing the Download File Name Our new file name and the path to the specified directory now show on the download screen These settings will only apply for the currently selected measurement NOTE This process will have to be repeated for each measurement to be downloaded if you wish to specify a file name and destination folder each measurement For multiple file download each measurement will use the file name as its base name For example if the file name is Roadtest then the download file will be named Roadtest 10 20 To change the name of the downloaded file enter a new name in the File name
481. ressing the D key turns the backlight on or off Note If after powering up the 824 the display is not visible turn the unit off by holding down the power key Turn on the power again by pressing the power key and holding it down until you hear three beeps in quick succession 3 4 To turn on the power Step 1 Press the key Step 2 Allow the instrument to stabilize as indicated by the hourglass symbol in the screen s upper right hand corner Step 3 As soon as the hour glass icon disappears the Sys tem 824 is ready to acquire data As soon as the System 824 is turned on you can view the battery life and display settings through the PWR display To do this Step 1 Press the key so that the following PWR dis play appears PUR Source ExT 15 Battery au Externalila ov Back lighte Off Contrast 62 Hold to turn off This simple display indicates that the System 824 18 plugged into an external source which is 13 5 volts the battery is 97 full the backlight is off and contrast is at 6296 Step 2 From the PWR display you can adjust the Power settings To do this press the key The follow ing Power menu appears Power H 824 Reference Manual 9 29 09 Check menus allow you easy access to system or instrument settings The or arrow keys allow you to select the desired menu item and by pressing the D key you can make changes to the setting The
482. ressure so a corrected level should be used Similarly the sensitivity of the microphone itself is a function of temperature and static pres sure For directions on compensating for temperature and static pressure during calibration see Correction of Calibra tor Output Level on page 2 17 9 29 09 Step 4 Step 5 Step 6 Step 7 Step 8 Using the W key highlight the Calibration menu item then press the Y key The following screen appears Calibration Calibrator SH The value of Cal Level 3rd item on the screen must be set equal to the output level of the calibrator to be used for the calibration typically 94 or 114 dB Ifthe value indicated is not equal to this value use the W key to highlight the Cal Level menu Press the Y key use the horizontal and vertical arrow keys to input the correct value and press the Y key to make the change Place the calibrator over the microphone Using the W key again highlight the Change menu item Press the key to start the Calibration process When prompted by the message shown below press the key to continue the Calibration process If you wish to abort the calibration procedure arrow key to select Cancel and press the Y key Calibration While the system is stabilizing the measured level Is indicated on the left of the screen and the difference between the measured level and the Cal Level Setting are show on the left and righ
483. ring Settings on page 7 23 and Logging SLM Exceedance History Settings on page 7 40 The System 824 Training Manual available from Larson Davis is also an excellent reference Excd a Display 5 52 Event recording begins when any one of the three following conditions is satisfied The instantaneous sound pressure level Lp exceeds the value of SPL Exceedance Level 1 set by the user The instantaneous peak level Pk 1 exceeds the value of Pk 1 Exceedance Level set by the user The instantaneous peak level Pk 2 exceeds the value of Pk 2 Exceedance Level set by the user Event recording ends when all three of these levels Lp Pk 1 and Pk 2 are below their respective exceedance levels minus the Hysteresis level setting The exceedance will only be saved if its duration is longer than the minimum duration setting The Exceedance view shows a record of each exceedance recorded when the sound pressure level went over a predetermined threshold You can access the Excd History view display by selecting Excd History with the Check key from within the main View menu The Excd a display consists of six major components Display Label Exceedance Number Exceedance Date Time Reading SEL Reading Exceedance Duration The display is shown below 824 Reference Manual 9 29 09 Display label Ex cd a if Exceedance Date Time 12JIuni 255 89 49 45 Reading
484. ring the measurement If one or more overloads have occurred the display shows the total number of overloads If no overloads have occurred the display shows a No Overloads have occurred message instead Run Log LOG amp SSA The Run Log displays the start and stop times dates of the active measurement in the System 824 s memory You use the and W arrow keys to scroll through the log records The Run Log display can be accessed by simply selecting Run Log with the Y Check key from within the main View menu The Run Log display consists of four major components Display label Log number Event Date Time 5 40 824 Reference Manual 9 29 09 Run Stop indicator The Run Log display is shown below for the LOG and SSA instruments Display label Run Log Previous action Men H us23 10 19 eem i Previous record 2j Log Number Run Stop Indicator Event Date Time stop 1 Key Mon 99 925 18 19 B4 44 Current record Number of time Time Hi story at history samples for this run stop period RUN u423 10 23 49 Next record The following explains this display s components Display label Shows the display currently being used for example Run Log Log Number The Log display shows the start and stop times dates of measurements in active memory Each measurement is logged in memory in the order that it occurred The Log Number
485. riod is set to 1 32 of a second the history period will be forced to multiples of 4 to support the maximum data rate of 8 samples per second and the warning Setting Conflict is displayed Other Level LOG only 9 29 09 This setting provides the following four options 1 32s This sets the History Period Unit to 1 32 sec ond intervals Since the instrument samples the detec tor 32 times per second this is the smallest resolution time period that you can use If you set the time his tory period to 1 32 second i e period setting 1 and unit setting Sample 1 325 the instrument will store every sample it takes 1 0s This sets the history period unit to one second 10 0s This sets the history period unit to ten sec onds 60 0s This sets the history period unit to sixty sec onds Use the Other Level setting to select the second measurement level stored in each time history record along with the Leq This setting provides the following options Using ID Setting Files 7 33 The Any Data information stored with the Time History is accessed through the Time History menu under the View key Resolution LOG SSA 7 34 None The instrument stores the Leq but does not store a second level Pk I The second level the instrument stores is the greatest instantaneous level Lpp detected by the pri mary peak detector that occurred during the time his tory period The primary peak level is weight
486. ription of each menu item Menu Items Purpose Excd Data View Excd a and Excd b displays Locate Locates a specific Exceedance record Settings Modifies the Exceedance settings Graph Adjusts the scaling of the Excd Time History graph The Daily History display has two different check menus one for the Daily data and one for the Hourly data When viewing the Daily History the following menu appears after pressing the Check key Following is a chart of the Daily History check menu with a description of each menu item Menu Items Purpose Hourly Data Displays hourly data First Displays the first hourly record Last Displays the last hourly record Find Displays a specific record Settings Modifies the Daily History settings 824 Reference Manual 9 29 09 In the Hourly display press the Check Y key and the following menu appears Following is chart of the Hourly History check menu with a description of each menu item Menu Items Purpose Daily Data Displays Daily data First Displays the first hourly record Last Displays the last hourly record Find Displays a specific record Settings Modifies the Daily History settings Graph Adjusts the scaling of the Hourly Leq graph NOTE Check menus are not available for the Metrics PassBy and Wind Tach views 9 29 09 Using ID Set
487. rnal Battery Level in Volts nn n V RI71 f SSA AUD RTA filter LIVE Level nnn n dB TAL fis ANSI filter R172 f SSA TAL RTA filter CURRENT Leq nnn n dB fis ANSI filter R173 f SSA TAL RTA filter OVERALL Leq nnn n dB fis ANSI filter R174 f SSA LOG RTA filter selected frequency 2 20 824 Reference Manual 9 29 09 R175 ALL End Date and Time ddmmmyy hh mm ss R176 ALL Current End Date and Time ddmmmyy hh mm ss R177 ALL OverAll Reset Began Text Reset or Began R178 ALL Current Reset Began Text Reset or Began R179 ALL Total bytes of RAM installed nnnnnnn SLM R180 ALL Current Instrument Type ccc R181 ALL Number of Data File Records nnn R182 ALL Data File History Record Size nnnnnnn R187 ALL SLM Firmware Rev Number amp n nnn ddmmmyyyy Revision Date R188 SSA RTA Spectra at Lmax nnn n dB R189 ALL Logic Input State or off R190 ALL Noise Floor Indicators or cccc flags R191 AUD Audiometric Test Rise Time nnnnn nn R192 AUD Audiometric Test Fall Time nnnnn nn R193 AUD Audiometric Test On Time nnnnn nn R194 AUD Audiometric Test Off Time nnnnn nn R195 AUD Audiometric Test Plateau Time nnnnn nn R196 AUD Audiometric Test Overshoot Level nnn n R197 AUD Audiometric Test Level nnn n R198 AUD Audiometric Test FFT Frequency nnnnn nn R199 AUD Audiometric Test Carrier
488. rnal weather transducers with inclusion of data in Views and Data Displays for SSA and LOG instruments Real time 1 3 octave spectrum analysis with rapid spectrum vs time autostorage and triggering for sound decay measurement RTA Simultaneous operation of sound level meter with independent frequency and 1 3 octave analyzer function weighting SSA Advanced time history feature allows you to store up to 38 different parameters including spectral data with each time history sample Narrow band real time frequency analysis with 400 line FFT and Hanning Flat Top or Rectangular window FFT Mode Standard memory 2 MB sufficient to store one of the following 30 000 point 1 3 octave SSA Leq time history 20 000 intervals with 1 3 octave Leq spectrum 824 Reference Manual 9 29 09 9 29 09 12 300 SSA intervals with Leq amp Max 1 3 octave spectra 60 000 LOG intervals without Ln 35 000 LOG intervals with Ln 1 000 000 point time history 70 000 RTA 1 1 octave spectra 28 000 RTA 1 3 octave spectra 2400 FFT 400 line snapshots AC DC output unweighted with gain to 50 dB and attenuation to 20 dB Flash memory for in field firmware upgrades Multi tasking processor provides simultaneous measuring viewing transferring and printing of data RS 422 RS 232 compatible interface Serial bit rate to 115 kbps Direct report printouts Windows based software included for setup control and high speed
489. rning will displayed indicating that the measurement must first be stopped 4 10 824 Reference Manual 9 29 09 Recalling Stored Data When recalling a data file the System 824 will automatically switch to the instrument that the data file was stored as i e from Logging to SLM amp RTA The Data Files screen shows the currently selected record number the ID used to take the measurement the start stop dates and times and the total bytes used by the record 9 29 09 Measurement data that has been stored can be recalled for review at any time To recall a data file do the following Step 1 Press the Il Data key and a screen similar to the following appears Store File Recall Files Step 2 Use the up and W down arrow keys to highlight Recall Files and press the Y check key The following appears Data Files B SLHERTA SSA SLM amp Real Time Analy 1999 18 59 43 to 51 1 99 1 59 48 1463 bytes A summary of each data file can be viewed to determine if it is the desired measurement To view each data file summary use 43 up and W down arrow keys Step 3 You can recall the selected Data File by pressing the Y Check key The following screen appears Data Files Quick Start 4 11 The Data Files check menu includes the following Menu Items Description Recall Data Recall the stored data file s measur
490. rom the 824 Do you want to remove the setup HFT FFT from the 824 The setup will be deleted from the 824 and the Utility pro gram 824 Reference Manual 9 29 09 Locking and Unlocking Setups To prevent accidently deleting a user defined setup right click on the desired setup and select Lock Setup from the popup menu Note that if you have just created a new setup the setup must first be stored to the 824 before it can be locked Downloading Measurement Data To display measurement data stored in the 824 select Down load View from the View menu or hit the Download View button from the tool bar stored measurement information is retrieved from the 824 and displayed in the Download View window 824 Utility i n x File View Setups Data Help Pull down menu Show Files of Type Data File First entry in list Data File 5 fff Title FFT Analyzer shows the active 1 SLM amp RTA StartTime 2000 Jun 28 17 32 14 measurement 2 RT60 B EndTime 2000 Jun 28 17 32 19 Size 1022 bytes 3 Logging 4 SLM Location 5 FFT Note 1 Select Download Filename Directory C Program Files Larson Davis 824 Utility Filename 28Junt7tsImdl Bowntosd For Help press F1 NUM 2 Measurement list box 9 29 09 Using the 824 Utility Software 10 17 Above the measurement list box is a pull down menu listing
491. rpose Items SLM SLM data with graphic display of Time History Any Data Tabular display of SLM data RTA Live Real time frequency analysis display RTA Leq Leq frequency analysis display since the last reset RTA Max Frequency spectrum associated with the highest SPL RMS level since the last reset RTA Min The minimum level recorded for each frequency during the measurement Intervals Shows an Leq spectrum Max or Min spectral data a broadband Leq Lmax Lmin SEL Lpeak and Spectral Lns for each interval period 824 Reference Manual 9 29 09 SLM Shows the Leq for each time history period Time in graphical form plus the selected History advanced T H items RTA Time Shows the spectral data for each time History history period Live Leq Run Log Displays the start and stop times dates of the active measurement Ln Ln percentile levels exceeded n percent of Centiles the measurement time for broadband and spectral data SSA Displays of the following views can be accessed through the s View key when using the SSA instrument Additionally the RTA Live RTA Leg RTA Max and RTA Min can be easily switched between each other by using the move to any of the other views The D or 4 arrow keys can used to move the cursor SSA Displays Including 1 1 or The following are examples of the graphical displays for the 1 3 Octave Spectr
492. rsor along the time axis Time at Cursor Shows the time in seconds of the sample indicated by the cursor Current Sample This is the current sample number as indicated by the cursor Total Number of Samples Shows the total number of samples taken for this exceedance Total Number of Excd Records Shows the total number of exceedances recorded System 824 Views 5 57 The exceedance time history includes 10 samples preceding the event and 10 samples after the event The maximum number of samples that can be stored are 128 In this case only the first 128 samples are stored including the 10 pre event samples Daily Views Daily a Display 5 58 Graph of Exceedance Time History Shows graphically all of the samples taken for the time history These values follow the instantaneous sound envelope determined by short period Leq samples As a result it does not exhibit the relatively slow decay characteristics associated with Slow or Fast detectors The Daily history logs daily sound statistics including Leq 24 LDN CNEL Ln s Max Min and Peak data The measurement period is from 12 00 midnight to 12 00 midnight each day For each hour it logs Leq Background Leq and the hourly Excd Leq You can access the Daily display by selecting Daily with the Y Check key from within the main View menu then cycling through the views with the and arrow keys until the desired display appears The hourly data is accessed by pressi
493. rt Print Key Refer to the section Printing PRINT key displays the printing options menu Reports on page 8 2 for more These options enable printing of graphical and tabular data information on printing reports directly from the instrument to a serial printer You can create high resolution presentation quality reports when printing to a laser printer because of the instrument s PDL 3 Page Description Language capabilities Draft quality tab 9 29 09 Front Panel Keys Functions and Menus 3 37 The Print menu changes depending upon the specific instrument being used 3 38 ular data reports can also be printed on virtually any serial printer The Print menu provides the ability to output reports con taining all the data gathered for the measurement to an attached printer The main Print menu is activated by press ing the PRINT key With an appropriate printer connection you can print a num ber of reports The Recall Format sub menu option is used to enable various reports Do this by highlighting the corre sponding menu item and pressing the key Use Tailored Report to print the custom reports that are defined as part of an instrument definition SSA and LOG IDs only Use the Customize sub menu to further customize the report settings In this sub menu you can select the specific ele ments to include in the report and also the various data ranges for histograms time hist
494. rts called All Long and All Short When the summary report is recalled the Customize menu is changed to reflect those parameters which will be printed in the summary and tailored reports The Customize menu is formatted with all of the parameters for each report selected in the Recall Format menu You can choose to print the default parameters that are recalled for each report or you can go into the Customize menu and make further changes to the parameters Before beginning to Print always recall the file and select the data that you would like to print The following shows how to print from the Recall Format Printing a Report 8 7 Step 1 To print from the Recall Format menu press the PRINT key The following screen appears Step 2 Use the and W arrow keys to highlight the Recall Format menu Press the D key and the fol lowing screen appears Recall Format Step 3 Use the and W arrow keys and select the report that you want to print Summary Tailored All Short All Long or None Enabled Default Settings Values for the The following tables show the default settings for each of Recall Format Reports the templates available from the Recall Format menu Sum mary Tailored Long Short and None Enabled Summary Report Template This template shows the default settings for the Summary Report The Summary Report includes the Data Report and the Log Report After selecting th
495. rtual Instruments completely expanded 1 4 824 Reference Manual 9 29 09 Click to Display Page Return to Previous View Links Click to Display Page 9 29 09 Table of Contents Introduction L Overview i Front Panel Keys their Functions and Menu C Quick Start System 824 Virtual Instruments HL System 824 Virtual Instruments LF Selecting an Instrument ID Tu Sound Spectrum Analyzer SSA i 55 Measuring Ranges LN Percentiles Spectral AC DC Output Ei Logging SLM L Time History Interval History Exceedances Percentiles Broadband L Sound Exposure LOG and ISM Measuring Ranges Left click on any text field Chapter name Appendix name Table of Contents Index or any sub heading and the page displayed on the right will jump to the page associated with that text field To return to the page which was displayed previous to clicking on a bookmark text line right click on the display page then left click on Go to Previous View The Table of Contents and the Index have a page number associated with each item For the Table of Contents left click on the text line and that page will be displayed For the Index left click on the page number itself to display the page associated with that entry To return to the previous display follow the procedure described in Return to Introduction 1 5 About This Chapter Formatting 1 6
496. rum can be averaged using the Average item on its check menu There is effectively no limit on the number of spectra that may be averaged Spatial Avg Check Menu The 824 will prompt you to reset the Spatial Avg buffer This does not reset the Avg History 9 29 09 Each display that can show a spectrum has a check menu item Average that when selected will prompt the user Add to Average It then offers the following choices Yes averages the spectrum being viewed to those previ ously averaged e No the spectrum is not averaged into the previous aver age but the spatial average display is shown Cancel nothing happens and the previous display 18 shown Once one or more spectra have been averaged they can be stored into the Avg History The Spatial Avg check menu is shown below To access the check menu simply press the Y check key when in the Spatial Avg display Spatial Pra a Hote HI Test gt The check menu offers the following options Note Note is used to describe this average which is to be stored to the Avg History Store Store Spatial Average in Spatial Average History e Reset Resets the Spatial Average buffer Avg History View the Spatial Average History Rooms View Room Criteria for this spectrum RTA optional 11 37 If the data being viewed has come from a stored file the average function is not available and will beep instead of
497. s 574 Run Mode Logic Input TRUE Level Low High 575 Logic Outputs Control Setting bit mapped word 3 outputs X 5 states 576 End Mode Never L lt L Input Time Count 577 End Level nnn n dB S78 RTA End Time ss ssss Sec 579 End Samples nnnnn S80 RTA End Logic Input TRUE Level Low High S81 RTA End Then Repeat Mode Stop Repeat Average S82 RTA Repeat Count nnn 0 to 255 times 583 Average Count n 0 to 9 times S84 RTA Annunciator if right digit is numeric it will auto increment S85 RTA RT 60 calculation dB down setting 5 10 20 30 S86 RTA Horizontal Graph Scaling 1 2 3 4 725 1024 S188 RTA Print Live Summary or Event Data No Yes S189 RTA Print Leq Summary or Event Data No Yes A 52 824 Reference Manual 9 29 09 5190 Print Max Summary or Event Data No Yes S191 RTA Print Min Summary or Event Data No Yes 5192 Event working report enable No Short Long 5199 Event ByTime REPORT LOWEST nnnnn RECORD 5200 Event ByTime REPORT HIGHEST nnnnn RECORD 5213 ByTime History Record nnnnn 5195 Spatial Average History Report Enable S201 RTA Temporary Note Field for Spatial Aver age 5139 FFT Repeat on Count complete 0 No 1 Yes 5138 FFT Enable Overload Skipping 0 No 1 Yes 9 29 09
498. s is chosen from any spectrum check menu Display label ROOMS HCE Level in dB of selected filter 47 Selected filter frequency Room level in dB Be SIL hee eens 36 96 Room data W MCE Z27 un M NCB status gt NCB curve line an annoyance or loudness spectrum indication The NCB status indicator can show the following Under indicates that SIL speech interference level is under the defined range for NCB Over indicates that SIL is above the defined range for NCB H indicates the NCB Hiss check failed indicates the NCB Rumble check failed 824 Reference Manual 9 29 09 Rooms RC Use the amp up and W down arrow The Rooms RC display calculates the noise criterion for the keys to move between the RC and spectrum being displayed when Rooms is chosen from a NCB displays 9 29 09 check menu Display label ROOMS RC Level in dB of selected filter 42 Selected filter frequency lt lt Room midfrequency average level a E Voc mue 41 4 Room data gt 25 559 RC status Me CRI RCB line fixed slope annoyance or interference The RC status indicator can show the following Under indicates that Lmf
499. s The cursor will not move to the next graph point until the selected number of data points have been displayed numerically This facility allows up to 1024 numeric data points to be displayed for each graph cursor point and allows the user to observe an overall shape of the measured data on screen without the need for scrolling RT 60 9 29 09 Graph H Adjusts the horizontal graph scale Adjust Graph 2 15 Press the 43 up W down arrow keys to adjust the horizontal scale factor Press the check key to exit The RT 60 display is accessed by pressing the View key and highlighting Autostore The menu appears like this Ae senate Press the D right arrow key to bring up the View Autostore display view menu RTA optional 11 33 View Autostore Autostore HuTime 5 2 Om RT 68 Highlight RT 60 and press the check key RT60 The RT 60 analysis display uses the ByTime history to calculate a room decay time This time 1s calculated from the cursor position to a point a number of dB down as set by the RT60 dB Down setting and then extrapolated to a drop of 60 dB using a Least Squares slope calculation method Display label RT 60 time in seconds at frequency shown Current ByTime sample number J3 9e 154 35i 1 RT 60 dB down setting RT 60 delta time eed Horizontal graph scaling Selected filter frequency
500. s and press the Y Check key The following screen appears Overview 2 13 Calibration Power off the instrument prior to connecting microphone preamplifier the high voltage spike created when connecting while the instrument is on can damage sensitive electronic components 2 14 Data Files i SLH amp ETH SSA SLM amp Real Time Analy HiSepl23252 55 45 to 55 1999 69 36 68 2543 bytes Step 2 Press the up and down W arrow keys until the desired file is indicated Press the check key select Recall from the menu and press the check Y key again Calibration is one of the functions available from the Tools Menu Step 1 Press the TOOLS key Calibration C lock Tiner Hemoru Lock 824 Reference Manual 9 29 09 NOTE The output level specified by the calibrator manufacturer will be at standard temperature and pressure In practice the level is a function of temperature and static barometric pressure so a corrected level should be used Similarly the sensitivity of the microphone itself is a function of temperature and static pressure For directions compensating for temperature and static pressure during calibration see Correction of Calibrator Output Level on page 2 17 9 29 09 Step 3 To setup the calibration process press the key to move into the Calibration Menu Calibration Calibrator 5 H Step 4 set the calibra
501. s 0110 2 10 VIEWS oio oe rbi re ate re t 2 11 Selectin Sa VIEW aiite dt AT Rd 2 11 Data Storage and Recall esses ener 2 13 Storing Data i ARR nh RE e tu e RUE 2 13 Recalling un hie Re CURRO Rd PR 2 13 Calibration peces 2 14 Correction of Calibrator Output 1 2 17 Chapter 3 Front Panel Keys Functions and Menus 3 1 dame ete n IG RROMBE 3 3 Power up the Instrument Viewing PWR Display sene 3 4 Power Settings one tede Re RI ED 3 6 Extra Notes on Power Conservation 3 8 D RUNS ON KE aeneo ie e aes 3 8 MAU EN 3 9 ID Pause Key aine epe tte ar OI TEE EIER 3 10 Pause ER 3 10 Pause Back Erase e ce tct t tete tertie 3 10 cu duoc sas ce de epe bisce cc tae 3 11 9 0 D 5 Arrow Keys eee nnns 3 11 D CheckKey etti etia eie dedere 3 12 View aq nccceccccccccccsesessssesescsesssescecsesesessssesesessvecscsesesecsesesesssseecsesaeecesseseeessesesenes 3 12 W Date Keys se cR NO RUE TU Hn 3 13 PAIN i ta 3 14 Save ceret et eerie NE ar neqae hee 3 16 deti mes einem 3 16 Name ote eire utet o e ee eeu 3 16 Write Protect Delete Write Enable 3
502. s Settings 8 1 Cal Settings 8 1 SSA Settings 8 2 554 Run Stops Summary For Help press F1 Deser2 Setup Setup Descr Location Notel Note2 verall Measurement Start Time Enter Address Line 2 slm amp rta ssa SLM amp Real Time Analyzer 07 Sep 1999 21 54 32 L 1 67 0 00 dBA L 33 33 0 00 dBA L 66 67 L 8 33 0 00 dBA L 50 00 0 00 dBA L 30 00 Interval Records Disabled Number Interval History Records Enabled Number History F X b T Bo 9 29 09 Using the 824 Utility Software 10 27 10 28 The data is displayed on the right side of the screen If the data record is too large to be effectively displayed in that area a message will appear at the top of the displayed record indicating that it is available for export only 824 Utility olx File Setups Data Help Real Symantec RTA Events available for export only sc Symantec File Translated C Tom Dobson Palatino Fonts 8S ep21r slmc C The Microsoft Network Model Serial Number 824 0271 Uninstall Information 2101 1 610 Windows Messaging Name Enter Company Name Enter Address Line 1 RECYCLED Enter Address Line 2 temp 7 rooms ta 1 1 Octave Real Time Analyzer Tom Dobson Frame Doc s Helvetica Font Optim
503. s a logarithmic measure of the quantity and not the quantity itself The word decibel is often added after the number to express the same thing When frequency weighting is used the annotation is often expressed as dB A or dB B Measurement Duration T The time period of measurement It applies to hearing damage risk and 1s generally expressed in hours Standard ANSI 512 19 Microphone Guidelines Microphone Types A device for detecting the presence of sound Most often it converts the changing pressure associated with sound into an electrical voltage that duplicates the changes It can be composed of one of the following types D 12 824 Reference Manual 9 29 09 9 29 09 Capacitor Condenser A microphone that uses the motion of a thin diaphragm caused by the sound to change the capacitance of an electrical circuit and thereby to create a signal For high sensitivity this device has a voltage applied across the diaphragm from an internal source Electret A microphone that uses the motion of a thin diaphragm caused by the sound to change the capacitance of an electrical circuit and thereby to create a signal The voltage across the diaphragm is caused by the charge embedded in the electret material so no internal source 18 needed Microphone Uses The frequency response of microphones can be adjusted to be used in specific applications Among those used are Frontal incidence Free Field The microphone has been adjusted t
504. s automatically stored in the Autostore record if Save ByTime is set to Yes For setups with a linear detector spectra are stored once every linear detector time For setups with an exponential detector samples are stored every 1 256 of a second 0 004 second to every 32 seconds Pretrigger Allows the user to select the number of pretrigger samples that are stored with Autostore ByTime record The 824 keeps a circular buffer of the most recent 400 samples The buffer is reset every time a new run is started The number of spectra in the buffer is displayed in the Trigger Status view This setting determines how many of these spectra to copy into the beginning of the Autostore record 0 400 samples 9 29 09 When Autostore is turned on ByTime records are automatically stored A typical trigger following settings having the Trigger Source 1 kHz Arm Level 80 0 dB Arm Mode L gt Arm Time 2 0 second would transition to arm after the 1 kHz filter level was greater than 80 dB for 2 seconds Arm Settings Menu Elapsed time and qualifying times are evaluated only when a new Bylime sample is created This causes the minimum effective time resolution to become the same as the update interval L indicates the level of the filter specified by the Trigger Source setting 9 29 09 Save ByTime This feature allows the user to enable or disable storage of ByTime data in an autosto
505. s general information such as Leq SEL Dose Projected Dose Lmin Lmax Peak Ln s exceedance and calibration logs Setup Report Yes Print the settings and their values for the SSA instrument Intv Report Short Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in the short report The Long reports adds the Ln values and Spectral LNs for the Interval period Hist Report Yes Leq for each time history period Print Range Intv Report Short You can customize the interval report by choosing the long or short report Lowest Record 00000 Selects the lowest interval record to be printed Highest Record 65535 Selects the highest interval record to be printed Hist Report Yes You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time history record to be printed Highest Record 799999 Selects the highest time history record to be printed Histograms SPL Histogram Yes Prints SPL histogram and overall Spectral LN report Lowest Level 045 Selects the lowest SPL histogram level to be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 5 0 Selects the SPL histogram resolution Pk 1 Histogram Yes You can customize the Peak Histogram report by choosing the long or short report Lowest Level
506. s high speed spectral data gathering optional FFT Adds Fast Fourier Analysis to the 824 optional AUD Gives the 824 the ability to certify audiometers used in conjunction with the AUDit software optional TAL Measures tonality according to DIN 45681 and appraisal of low frequencies according to DIN 45680 optional 1 precision integrating sound level meter satisfies IEC61672 1 tested with 377B41 microphone only IEC 60651 1993 60804 1993 and ANSI 51 4 1985 Introduction 1 7 The windspeed tacho and wind direction throttle position feature requires the firmware option 824 WND not included with standard System 824 configurations 1 8 Simultaneous measurement of sound pressure level using Fast Slow Impulse Peak and Leq detectors with A C and Flat weighting SSA ISM LOG and TAL instruments Exceptionally large dynamic range gt 93 dB for SSA and gt 115 dB for ISM and LOG Digital filters with real time rate to 20 kHz satisfying 1260 1995 Class 1 and ANSI S1 11 1986 Type 1 D meeting linearity specifications over a range of 85dB 1 1 octave 16 Hz to 16 kHz 11 filters 1 3 octave 12 5 Hz to 20 kHz 33 filters Automatic logging of sound level parameters including Interval data L statistics noise event detection using exceedance history and exceedance time history LOG only Measurement of windspeed tacho and wind direction throttle position using exte
507. s the key to select The instrument will beep once to signify that the measurement has been stored Press the Data key again and select Recall Files to view a summary of the stored data files The following screen appears Data Files if 4 SGLHERTH SSA amp Real Time Analy 3lMari222 18 59 43 to 3iMari9293 18 59 40 1455 butez Front Panel Keys Functions and Menus 3 13 To move from one record to another use the or W keys To exit the Data Files view press the to return to the previous display or select a new view using the VIEW key Pressing the V key from the Data Files display brings up a menu that allows you to recall data jump to beginning or end of all records find a specific data file or purge all data files Setup Key To the left of each ID is a symbol giving information about that ID The gt symbol indicates that the ID is currently active or that the ID is currently memory The lock symbol indicates that the ID is locked which protects the ID from being easily deleted Press TOOLS to write protect or un protect an ID The p symbol indicates that the ID is permanent and pre defined The symbol indicates that the ID has changed and has not yet been saved 3 14 824 Reference Manual The Data Files screen shows the currently selected record number 4 start amp stop dates and times and the total bytes used by the record
508. s the O Setup key The Edit Settings SLM amp RTA SSA is high lighted as the Setup menu appears Edit Settings li SLM amp RTA SSA gt SLMARTA SSA Step 4 Press the key and the Settings menu for the SLM amp RTA SSA instrument appears Title amp Rea l T LM gt RTA Intervals gt 9 29 09 Using ID Setting Files 7 3 Settings Descriptions Within the Edit Settings menu use and W keys to move from one setting to the next Use the D key or Q Check key to select the setting to be modified The key is used to return to previous menus 7 4 5 Step 6 7 Using the or W keys highlight the SLM option and press the Y Check key CREE 3 a amp Rea l i 5 TA Intervals Use W keys to highlight the Detec tor setting then press the key or Check key The Detector Settings menu appears Detector LS low 1 Me aea Gain 60 In the pop up windows use the A or V keys to highlight the Fast setting then press the Y Check key to accept the setting change The SLM amp RTA SSA instrument s Detector setting is now set to Fast Press the 2 Setup key to close the menu and return to the SLM RTA view Descriptions of the System 824 instrument s various settings are provided in this section The following will be covered Common SLM Settings Common Control Settings Logging SLM TWA Settings Log
509. s the right D arrow key to access the Interval Spectral LN displays The following menu will appear Highlight Spectral and press the check Y key to view the INTV Ln f display 9 29 09 System 824 Views 5 15 See the section Spectral LNs on page 5 21 for a detailed description of this display SSA Time History 5 16 IHTV Lrn f i i L 5 00 32 39 L5n n 40 0 31 6 9 0 38 6 29 75 Use the right D and left 4 arrow keys to move to each one third octave frequency To view the Spectral 1 through Spectral 6 displays the 6 Ln values use the up and down arrow keys Below is an example of one of these displays Levi 052600 12 58 56 The SSA Time History display consists of six major components Display label Record number SPL reading at cursor e Other level Status SPL history graph 824 Reference Manual 9 29 09 The SLM Time History display is shown below Display label 55A Time Histor Record number an F 120 4 Time cursor Leq reading at cursor gt gt 4 ri dp 100 Detector setting 4 SPL history graph Value of other level 47 BEA BD Other level selected in TH Ley setup 55H Time History m RECORD 1 F Hi iun Status indicator ze at
510. se Enable Ln Enables or disables Ln data Start Level Sets the minimum dB level to be calculated in the Ln data Ln 1 Percent Changes the percentage for Ln 1 Ln 2 Percent Changes the percentage for Ln 2 Ln 3 Percent Changes the percentage for Ln 3 Ln 4 Percent Changes the percentage for Ln 4 Ln 5 Percent Changes the percentage for Ln 5 Ln 6 Percent Changes the percentage for Ln 6 Spectral LN None Overall Interval Press the Check Y key while viewing the Ln Centile s spectral displays and the following check menu appears Start Level inl Ln z Percent Using ID Setting Files 7 71 7 72 Following is chart of the Ln Centiles spectral check menu with a description of each menu item Menu Items Purpose Start Level Sets the minimum dB level to be calculated in the Ln data Ln 1 Percent Changes the percentage for Ln 1 Ln 2 Percent Changes the percentage for Ln 2 Ln 3 Percent Changes the percentage for Ln 3 Ln 4 Percent Changes the percentage for Ln 4 Ln 5 Percent Changes the percentage for Ln 5 Ln 6 Percent Changes the percentage for Ln 6 Press the Check key while viewing the Ln Centile s spectrum displays and the following check menu appears Menu Items Purpose Settings Modifies the spectral Ln settings See table above spectral check menu items for a descriptio
511. se to view all of them selecting ALL binary from the simultaneously by selecting ALL lt binary gt or you pull down menu and highlighting select the file type from the list If you selected ALL one or more of the files from the lt binary gt highlight one or more of the files in the measure measurement list for download ment list box and click the Download button the selecting files of one type and _ selected files will be downloaded in their binary form highlighting one or more of the files from the list 824 Utility File View Setups Data Help Eafe 31 Show Files of Type Data File ALL binary v Measurements Pull down menu Data File 5 fit e FFT Title FFT Analyzer lt 8 1 SLM amp RTA Start Time 2000 Jun 28 17 32 14 2 60 End Time 2000 Jun 28 17 32 19 Size 1022 bytes Measurement list box 3 Logging 4 SLM Location lul 5 FFT Note 1 Note 2 Select Download Filename Directory C Program Files Larson Davis 824 Utility Filename 28Jun17f slmdl Download For Help press F1 To get back to the setup screen press If you selected files of the types SSA ISM LOG TAL the setup button on the toolbar FFT or RTA only this file type will be listed in the mea surement list box Select one or more of the files and click the Download button The following
512. sed together These displays are categorized as follows a SPL b Times c Min Max System 824 Views 5 25 The different views can also be accessed by simply selecting either Current or Overall SLM with the Q Check key from within the main View menu then cycling through the views with the D and arrow keys The 4 D arrow keys allow you to move through the views available displays Current SLM Overall SLM Display a SPL 5 26 d Peaks e TWA These displays can be accessed directly from the View menu screen by doing the following Step 1 Press the View key to enter the View menu Step 2 Highlight either Current SLM or Overall SLM Press the arrow key and one of the following screen appears Overall SLM 3 m 3 3 LI LI Step 3 Use the and 5 arrow keys to highlight the desired view Step 4 Press the Check key or the D arrow key to enter the selected view The Current Overall a SLM or SPL display consists of six major components Display label Current SPL reading and weight setting Selected detector Elapsed time 824 Reference Manual 9 29 09 Status SPL history graph The Current SLM a or SPL display is shown below Display label SLI Current a Status 54 Detector setting Slow 8 ED Current SPL reading and weight setting Elapsed time H1 47 93
513. ser to identify each noise source as the measurement is being taken There are 5 Markers and each Using ID Setting Files 7 35 marker can be assigned an 8 character description See page 7 55 for a description of the Marker display LOG and SSA Interval Settings Interval Settings are available on the LOG and SSA instruments The amp and keys move from one setting to the next The key changes the selected setting The key is used to return to previous menus The following table shows the available Intervals settings Each setting is described later in greater detail T The Intervals menu sets the System 824 to automatically store at regular time periods SEL Lmax Lmin and the six Ln levels The Interval time period can range from one second to nearly one hundred hours The Interval feature 1s particularly useful when monitoring noise levels for extended periods of time because you can determine how the statistical makeup of the acoustic environment has changed over time Menu Items Available Settings Options Intv Enable No Yes Intv Period hh mm ss Intv Time Sync No Yes Intv Save Ln s No Yes 824 Reference Manual 9 29 09 To store interval spectral Ln levels set Spectral Ln to Interval enable Ln and Interval histories and set Intv Save Ln to Yes Intv Enable LOG SSA Intv Period LOG SSA NOTE If set to 00 00 00 then the period is 0 1
514. set of data displays or VIEWS are available Selecting a VIEW There are eight different VIEW choices available in the SSA instrument Step 1 To display the set of available data presentations or VIEWS press the View key use the W 43 keys to scroll through the entire range of choices SLM Any Data RTA Intervals Time Histor 9 29 09 Overview 2 11 The VIEW choices for the SSA instrument type are as follows SLM Sound Level Meter parameters graphic and digital display Any Data Tabular presentation of sound level meter parameters RTA Live Live display of real time frequency spectrum RTA Leq Display of Leq spectrum over elapsed mea surement period RTA Max Display of the live spectrum corresponding to the maximum value of sound pressure Use the up da and down arrows whe during the measurement to select a menu item right D arrow E to enter a submenu and left 9 Min The minimum level recorded for each fre exit a menu quency during the measurement Intervals Sound Level parameters measured and auto matically stored at regular user defined time intervals Leq Spec Leq spectra measured and automatically trum stored at the interval rate Max Min Instantaneous spectrum corresponding to the Spectra maximum sound pressure level occurring during each of the user defined time inter vals or the minimum level for each fre quency as selecte
515. settings menu allows you to adjust the contrast or view ing angle turn the backlight on or off and adjust settings that control the power conservation features These power conservation features allow you to set the instrument to do the following Turm the backlight off after a set amount of time Automatically go into a standby mode after a set amount of time display blanks and serial port turns off Automatically shut off the instrument after a set amount of time e Conserve internal battery for memory retention If no keyboard activity is detected for the period of time set by the Backlight Time setting the instrument will turn off the backlight This conserves battery life since the backlight is a major consumer of battery power If Backlight Time is set to zero 0 then the timer 1s disabled and the backlight will stay on until turned off manually If the battery capacity is less than 30 the backlight will automatically shut off in 3 seconds to conserve power If the battery capacity is less than 15 the backlight will not turn on at all 9 29 09 Front Panel Keys Functions and Menus 3 5 Power Settings Use the and W keys to move from one setting to the next Then use the key to change the selected setting The key is used to return to previous menus Menu Items The Power menu provides the following menu items Description Status Settings Display s the Power Monitor display that shows the cur
516. sists of six major components Display label Leg Reading Leq Exceedance Leq Background 824 Reference Manual 9 29 09 Elapsed Time The Metric b display is shown below Display label Hetr ics b Reading 9 64 2 Leq Exceedance Exod Leq gdBhH Background Bk ad Leg 64 0 51 46 8 Elapsed Time B mg da B PassBy The and W arrow keys can be used to cycle between the Metrics PassBy and Wind Tach views 9 29 09 The following explains each of the display s components Display label This shows the current display for example Metrics b Leq Reading This shows the level of a constant sound over a specific time period that has the same sound energy as the unsteady sound over the same period Exceedance Leq This displays the average Leq of all the exceedance events Exceedance Duration Total time of all exceedances Background L This display shows the average Leq for the total measurement period minus the combined event Leg Elapsed Time This shows the elapsed time of the overall measurement The PassBy View has a single display that shows the largest single 10dB passby event detected The display can be accessed by simply selecting PassBy with the V Check key from within the main View menu System 824 Views 5 67 The PassBy display consists of six major components
517. sor will not move to the next bar until it shows all of the lines represented by that bar of the graph NOTE When more than one frequency is represented by a single bar the largest bar is represented on the display As you press the right and left arrow keys to move the cursor across the display you will notice that the cursor does not move until all of the frequencies represented by that bar have been displayed The left and right D arrow keys move the cursor to change the frequency and level displayed FFT Zoom The FFT zoom on the 824 allows you to view a representation of all 400 lines or a portion of the 400 lines on the display This is called a display zoom The up arrow key will zoom in the display by a factor of 2 to 8 This means that a zoom factor of 2 shows one half of the 400 lines on the display A zoom factor of 8 would show one eighth of the 400 lines on the display The down W arrow key zooms out to a full screen display of the FFT The zoom factor is shown graphically as a horizontal bar at the bottom of the bar graph The shorter the bar the greater the zoom The location of the zoom bar indicates the position of the displayed area of the spectrum Some examples of zoomed displays are shown below 32 Overall representation of spectrum No zoom Cursor indicates 5 to 6 points on graph Zoomed three to one Cursor indicates 3 points on graph Zoomed two to one Zoomed one to o
518. sponding to the frequency weighting selected for Leq see charts above and a second Lyeak level corresponding to one of the two alternative choices of frequency weighting e L 6 values with 0 1 dB resolution based on user selected percentages with 0 0196 resolution Date time and duration of interval e Six user selected values of L can be measured and stored as part of the automatic interval data storage func tion A special feature is the automatic measurement and log ging of data associated with noise exceedance events that are triggered by the sound level exceeding a user defined threshold Leq SEL and Lp for each event are logged along with a Time History of the sound level during each event Daily history and community noise metrics Overview 2 5 Selecting a Measurement Setup Note that each of the permanent setups has a letter p to the left of the setup name indicating that it cannot be modified or deleted It can be saved under another name and then modified 2 6 The simplest way to setup the instrument is to select the ID which most closely meets the requirements of the measurement to be made and then modify it to meet your specific needs The instrument 15 delivered with a number of permanent setups The standard ID delivered with the instrument is ISM The optional IDs available are SSA LOG RTA FFT AUD and TAL If the options for the SSA LOG RTA FFT AUD or TAL have not been purchase
519. sponse S et item number hh mm ss lt cr gt lt lf gt Example S30 09 25 00 Example S6 23 05 33 sets Timer Run Time 1 to 09 25 00 sets current time to 23 05 33 11 05 33pm A 36 824 Reference Manual 9 29 09 Setting List Com Instrument Description Comment mand Type Slx ALL RESET ALL S2 c ALL HEADING LINE 1 S3 c ALL HEADING LINE 2 S4 c ALL HEADING LINE 3 55 ALL MEASUREMENT TITLE S6 t ALL CURRENT TIME 574 ALL CURRENT DATE 58 ALL DAY OF WEEK 59 ALL Serial Communications Baud Rate S10 n ALL Serial Communications Address 511 ALL Serial Communications Output Flow Control 512 ALL Printer Serial Bit Rate 513 ALL Printer Serial Output Flow Control 514 ALL Logic Output Activation Mode S15 n ALL Logic Output Line Timer 516 ALL Logic Output Line 2 Activation Mode Heater control line S17 n ALL Logic Output Line 2 Timer 518 ALL LOGIC IN LINE MODE None Pause Toggle Level Alarm 9 29 09 Where c character t template n numeric and x option index S19 ALL External Power Type AC Pwr Battery Protects External Battery S20 ALL External Power Off Voltage S21 ALL POWER SAVE OPTIONS Blank LCD Auto Off Manual Off 522 ALL Standby Time LCD Blank amp Comm 0 to 99 mi
520. t have analog data acquisition generally used to record weather metrics 7 14 The Logic Output setting provides the following options Off The Logic Output 1s disabled RMS The Logic Output turns on when an RMS exceedance event occurs An RMS exceedance event occurs when the RMS sound pressure level SPL exceeds the threshold set by the SPL Trig ger Level setting The Any Data SPL used 15 the one specified by the Weight and Detector settings Peak The Logic Output turns on when the instantaneous peak level Peak I specified by the Peak Weight setting 1s over the Peak 1 Exceedance Level or when the instantaneous weighted peak level Peak II specified by the Weight setting is over the Peak 2 Exceedance level R P The Logic Output turns on when either RMS or Peak exceedance event occurs Intv The Logic Output turns on when an interval begins R I The Logic Output turns on when RMS exceedance event occurs or when an interval begins P I The Logic Output turns on when any peak exceedance event occurs or when an interval begins R P I The Logic Output turns on when either an RMS or peak exceedance event occurs or when each interval begins A D The Logic Output turns on when an event on one of the A D channels occurs These A D channels are typically used for weather monitor ing The Logic Output turns on when an RMS exceedance event occurs or when an event occurs on one of the A
521. t immediately 9 29 09 System 824 Views 5 23 5 24 Overall An accumulation of data over the entire SLM measurement period and is reset when the entire measurement is reset Exposure The Exposure displays show dose and projected dose the sound exposure E and C A Ln Centiles Display shows six selected L values a graph of L to Loo and a graph of the percent greater than level Stats The number of overloads and the number of events detected Run Log A listing of each run stop pause continue and mark action with its cause and date time of occurrence Time History Show the time history of Leq and optionally many other levels such as Lmax or Advanced TH setup items over short duration periods Can also show wind or tachometer data using external transducers Intervals Shows a full statistical history over a longer time period by providing TWA SEL Lmin Lmax Lpk p and six Ly values for each interval period Can also show wind or tachometer data using external transducers Excd History A special history which is saved when the level goes over a predetermined threshold SEL Lmax LPK I LPK II duration and time history if desired are saved for each exceedance record Can also show wind or tachometer data using external transducers 824 Reference Manual 9 29 09 Daily Ldn CNEL Leq 24 LPK I LPK II Ln s His
522. t sides Quick Start 4 3 High Range Calibration Note When using a prepolarized microphone during setup Electret should have been selected as the Transducer The High Range is not available when using a prepolarized microphone so the prompt concerning calibration of the High Range will not appear 4 4 of the display as shown below along with the message Wait indicating that the calibration process in underway and should not be interupted Calibration Change 113 925 0 1 Wait Step 9 When the calibration is complete the message will change to Stable after which the following display will appear to prompt the user to decide whether or not to calibrate the High Range as well If you decide to calibrate the High range as well as the Normal range there will be a forty second delay while the instrument stabilizes at the High range setting Il Calibration U Calibrate Calibrate High Range When the High Range is calibrated the microphone bias voltage is reduced from 200 to 20 volts This reduces the sensitivity of the microphone by 20 dB As a result the measured level indicated on the left of the display during the stabilization process should be 20 dB less than the Cal Level value 824 Reference Manual 9 29 09 Taking Measurements and Storing Data SLM amp RTA Measurements NOTE A solid black box indicates that the 824 is stopped with data and a hol low box indicates
523. tained in this chapter are subject to change without notice Please refer to calibration and test results for data on a specific unit NOTE Where possible tests were These specifications are valid for all System 824 s using the performed electrically using an ADP005 following options microphone adapter 18 pF e PRM902 preamplifier e 377B41 or 377A60 free field or random high sensi tivity microphone e 2540 or 2559 free field or random normal sensitivity microphones Standards Met ANSISI 4 1985 Type 1 61672 1 Class 1 tested with 377B41 microphone only 60651 1979 1 e TEC 60804 1985 Type 1 e 60651 1993 Type 1 60804 1993 Type 1 EC 61260 1994 Class 1 9 29 09 1 Declaration of Conformity Larson Davis Inc declares that Model 824 Sound Level Meter and Realtime Analyzer having been tested in representative configuration with PRM902 preamplifier 377B41 microphone and the following cables 010 microphone extension cable CBL042 AC DC output cable CBL006 serial interface cable is in accordance with the following directives 89 336 The Electromagnetic Compatibility Direc tive and its amending directives has been designed and manufactured to the following specifications EN 50081 1 1992 Electromagnetic compatibility Generic emission standard Part 1 Residential commer cial and light industry EN 50082 2 1995 E
524. tatz b 5 Peak I exceeded Peak I trigger Jd 1 did BF times Peak II exceeded Peak II Trigger 1 4AJEA Limes The following explains each of the display s components Display label This shows the current display for example SLM Stats b Peak I trigger This presents a summary of the number of times during the overall measurement that the Peak I level exceeded its pre programmed trigger level In this example trigger level is set to 140dBF and the Peak I level exceeded this threshold 0 times These may be considered as individual events Peak II trigger This presents a summary of the number of times during the overall measurement that the Peak II level exceeded its pre programmed trigger level In this example Peak II s trigger level is set to 140dBA and the Peak II level exceeded this threshold 0 times These may be considered as individual events Stats c Display The Stats c display consists of two major components 9 29 09 Display label e Overload message System 824 Views 5 39 The Stats c display is shown below Display label 5tatz c Overload message Ho Overloads have occurred The following explains the display s components Display label This shows the current display for example SLM Stats c Overload message The Stats c display indicates the occurrence of instrument overloads du
525. ted between the preamplifier and the body of the 824 For more details on the positioning of the 824 and the permitted length of the extension cable see Positioning the Meter on page 9 7 Selecting a Measurement Mode The System 824 can measure sound pressure level using using any of the following modes Integrating Sound Meter ISM measures sound level parameters which are stored manually by the operator 9 29 09 Performing a Sound Level Measurement 9 1 Selecting a Measurement ID 9 2 Logging SLM LOG measures sound level parameters and automatically stores the data based on a number of different user configured data logging methodologies such as Time History Intervals Exceedance History and Daily History Sound Spectrum Analyzer SSA which simultaneously measures sound level parameters and real time frequency spectra 1 1 or 1 3 octave bandwidths These data can be stored manually by the operator or automatically using the Time History and or Interval methodologies Details on the funtionality of each of these see System 824 Virtual Instruments on page 6 1 Select the desired measurement mode ISM LOG or SSA as described in section Selecting and Modifying Instrument Definitions IDs on page 4 12 If you are just beginning to use the instrument there will be only one ID permanent available for each of these modes However if other IDs have been created and stored using parameters different from the
526. ter that can be found by scrolling with the up and down W arrow keys Linear Scale Allows you to enter the sensitivity of a transducer in decibels relative to volts 128 99 to 127 99 FFT Optional 12 5 Auto Snapshot This feature allows you to automatically capture an FFT Snapshot on the completion of each FFT If Repeat is set to Yes then it creates a pseudo Time History The time interval between spectra Snapshots will equal the FFT calculation time see Bandwidth on page 12 3 multiplied by the number of counts selected for Count Averaging For more detail on Snapshots see Snapshot on page 12 11 FFT Display The FFT data displays are accessed through the View 9 key To select the FFT displays press the View key The following menu will appear FFT accesses the live FFT With FFT highlighted press the Check Y key to enter the spectrum and Snapshot displays FFT display the FFT snapshot data FFT The FFT display shows a live FFT spectrum Display label FF T Level at cursor e356 3 dB Selected filter frequency 72888 Count avg Me Hz 12 6 824 Reference Manual 9 29 09 You can view approximately 80 bars of the FFT at once When you are zoomed out you will notice that each bar represents several frequencies or lines Pressing the right arrow key moves to the next line The cur
527. th U S Occupational Safety and Health Administration OSHA regulations 6dB The 6dB option results in the Lay time weighted average which is merely a convenient rep resentation of the long term average noise level as opposed to the RMS noise level The Intv Spectrum allows you the choice of storing spectral data with the interval It will always give you the Leq Using ID Setting Files 7 39 spectra and one other spectra This setting provides the following three options None Does not store any spectral data besides the Leq spectra with the interval Stores the spectra associated with the maxi mum broadband level during the interval period Min Stores the minimum level obtained by each fil ter This is a bin by bin minimum level Logging SLM Exceedance History Settings Exceedance History Settings are Exceedance History settings allow you to select what data only available to the Logging SLM wil be saved in memory during an exceedance LOG instrument exceedance is defined as an acoustic event characterized by the instantaneous rms sound pressure level or peak level Pk 1 or Pk 2 going above or exceeding a predetermined level For further detail see the section LOG and SSA Triggering Settings on page 7 23 Triggering LOG The Triggering menu defines event triggering used to initiate an exceedance or event See Logging SLM Triggering Setting earlier in this chapter Excd Enable LOG
528. that we use linear units like sound pressure in acoustics or voltage in electrical engineering This is illustrated in equation D 1 below 2 dB 10104 25 20Log gt Po 20 Po Po Table 2 illustrates how a a tenfold increase of the sound pressure will result in an increase in 20 dB steps while sound power increases in 10 dB steps See the linear form Table 2 and compare with equation D 1 In conclusion dB values are always the same independent of using sound power or sound pressure as the base unit A 6 dB increase implies four times the sound power or two times the sound pressure Linear form non squared units Level form Exponential Form of 20 Exponent Ration of Value to Reference Ratio 1 10 0 10 10 20 100 10 40 200 107 46 1 000 10 60 10 000 10 80 100 000 10 100 1000 000 10 120 9 29 09 D 7 Department of Defense Level Lpop Dose Detector Eight Hour Time Weighted Average Sound Level L Energy Equivalent Sound Level Leq Exchange Rate Q Exchange Rate Factor q Exposure Factor k D 8 The Average Sound Level calculated in accordance with Department of Defense Exchange Rate and Threshold Level See Average Sound Level See Noise Dose The part of a sound level meter that converts the actual fluctuating sound or vibration signal from the microphone to one that indicates its amplitude It first squares the signal th
529. the File Menu 9 29 09 Using the 824 Utility Software 10 7 Setups will be retrieved from the 824 and will be displayed in the Setup listbox 824 Utility File View Setups Data Help at 4 Ed es Title Options Calib Power Date Time Controls Modem Timer System SLM amp RTA SLM ws Logging ws demo ROOMS i RT60 A Wie Larson Davis Model 824 RTGO B Serial Number 0138 TA LARM Revision 3 128 23Jun2000 FFT D 824 System Settings d Instrument Labels Instrument Type SSA Active Setup SLM amp RTA InsrumentName Enter Company Name Description 1 Enter Address Line 1 Description 2 Enter Address Line 2 For Help press F1 In the list of setup files the system setup is the first setup and is followed by all of the permanent and user defined set ups In the setup list box there are several parts of the Setup title that can be used to identify the setup type The name of the ID is listed in the right hand column For the permanent ID s this will be the Larson Davis instrument type For a user defined ID this can be any thing that the user defines The three letter Larson Davis assigned name is listed in the blue Ovals This indicates the type of instrument ID for which the setup was created SLM amp RTA stands for a permanent ID This would be tm SLM L an original setup defined at Larson Davis toe Logging and cannot
530. the settings may be further customized for your application NOTE If any changes have been made to the current settings you will be prompted with Active ID has Changed Save This section gives an example of using the standard settings in the SSA instrument The procedures in this example can be applied to the other Model 824 modes and instruments by simply substituting the other instruments specific settings for those of the SSA instrument Settings Example SLM amp RTA SSA If the 824 is already in SSA mode there will be a gt to the left of SLM amp RTA SSA In which case skip to Step 3 below 7 2 There are four general steps to setting up the SSA instrument 1 Press the SETUP key 2 Select the SLM amp RTA SSA setting 3 Press the SETUP key again 4 Enter the EDIT Settings menu The following steps you through the example procedure of setting the SLM amp RTA SSA instrument s Detector setting to Fast Step 1 Press the O SETUP key A menu similar to the following appears Edit Settings SLHARTA 25207 824 Reference Manual 9 29 09 If you have not already saved your Step 2 Select SLM amp RTA SSA from the menu by NO data you will be prompted to save it the or W keys and then pressing the at this step Check key SLM RTA screen appears 0 SPL The System 824 is now set to the SLM amp RTA SSA instrument Step 3 To access the Settings menu pres
531. the syntax indicate optional characters and operands cr carriage return lt lf line feed Types of History Each history is assigned a number history number so that it can be identified explicitly with the Advance Backup Find commands and is shown below Denoted in history_number 1 Exceedance E 2 Interval 3 Daily D 4 Run Log L 5 Calibration C 6 Time H 7 Histogram Table T syntax by Advance Advance a number of records from present record number If no num record number of records is provided 1 18 assumed Syntax Response A dvance num record history number lt cr gt lt lf gt Example A Advance current history 1 record Example A5 Advance current history 5 records Example A9 5 Advances calibration history by 9 records 9 29 09 A 55 Backup Backup a number of records from present record number If no num record number of records is provided 1 is assumed Syntax Response B ackup num record history number cr If Example B Example B5 Example B9 5 Backup current history by 1 record Backup current history by 5 records Backup the calibration history by 9 records from the current calibration history Find Find record number directly Syntax Response F ind num history number lt cr gt lt lf gt Example
532. the trigger settings met which means that the level must drop below 50 dB for 2 seconds 11 24 824 Reference Manual 9 29 09 Autostore Views If triggering is enabled the record is stored when the End condition is met or when the R S key stops the measurement If triggering is not enabled the record is stored when the 8 R S key stops the measurement If you just came from the Trigger Setup display press the 4 left arrow key to back out to the main VIEW menu 9 29 09 The measurement will repeat 2 more times before stop ping for a total of 3 measurements As the settings are changed the Trigger Setup display will show the relevant settings in an easy to read form An Autostore is a historical record of triggered data that is stored automatically when the Autostore setting is set to Yes The Autostore includes summary data Leq Max and Min spectra covering the entire duration of the Autostore and optionally ByTime spectra 60 analysis of the ByTime spectral time history is also provided The Autostore Display Views are accessed through VIEW key To select the Autostore Display Views press the VIEW key and amp up and W down arrow keys to highlight Autostore The menu will appear like this Now press the D right arrow key to bring up the View Autostore view menu View TEE Press the D right arrow key to select the available Autostore summary data views which are Leq Max
533. ti aliasing gt 75 dB Summation of output signals 1 0 dB 0 4 dB typical Flat frequency range 10 Hz 20 kHz relative attenuation lt 0 15 dB Filter type Digital Octave frequency ratio Base 2 See IEC 61260 Annex A AC DC Output SSA mode only 824 Menu 3 5mm Connector Tip 3 5 mm Connector Ring AC 1 AC 2 Flat AC output C weighted AC output AC 1 DC Flat AC output Weighted DC output AC 2 DC C weighted AC output Weighted DC output AC 2 AC 1 C weighted AC output Flat AC output Measurement Range SSA mode only 04 Gain 10dB Gain 20db Gain 30dB Gain 40dB Gain 504 Gain NF Start End s NF Start End 2 NF Start End NF Start End Start End bd NF Start End AW 485 0528 80 24 38 80 28 108 80 8 23 9 20 88 68 6 20 78 5 cw 3 48 8 8 2 38 80 28 108 80 9 23 9 20 88 68 8 20 78 5 33 108 75 21 33 98 33 88 50 23 40 78 38 8 8 FLA 32 48 28 80 25 38 8 80 8 8 16 0 23 78 55 31 5 23 78 95 63 0 18 78 60 125 8 78 70 250 8 78 70 500 8 78 70 1000 8 78 70 2000 8 78 70 4000 8 78 70 8000 13 78 65 NOTE A weighting C weighting and Flat are measured to ANSI 81 4 60651 standards for SLM linearity 1 3 octave filters listed are measured to the IEC 61260 standard for Class 0 linearity which is 0 3 dB
534. time history record to be printed Histograms SPL Histogram Yes You can customize the SPL Histogram report by choosing the long or short report Lowest Level 045 Selects the lowest SPL histogram level to be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 1 0 Selects the SPL histogram resolution Pk 1 Histogram Yes You can customize the Peak1 Histogram report by choosing the long or short report Lowest Level 110 Selects the lowest Peak histogram level to be printed Highest Level 140 Selects the highest Peak histogram level to be printed Resolution 5 0 Selects the Peak1 histogram resolution Pk 2 Histogram Yes You can customize the Peak2 Histogram report by choosing the long or short report Lowest Level 070 Selects the lowest Peak2 histogram level to be printed Highest Level 120 Selects the highest Peak2 histogram level to be printed Resolution 1 0 Selects the Peak2 histogram resolution 9 29 09 Printing a Report 8 19 None Enabled Report When None Enable is selected from the Recall Format menu then all of the reports are disabled and will not be printed This allows you greater ease in printing only a selected number of reports After selecting this template you can modify it as explained in Printing a Custom Report on page 8 23 None Enabled Report Template SSA instrument Report Settings
535. ting Files 7 79 7 80 824 Reference Manual 9 29 09 Printing a Report The System 824 allows you to print a report from data col lected during a measurement This chapter will discuss the following aspects of printing reports Connecting the 824 to a Serial Printer Printing Reports Defining and Printing Tailored Reports Printing a Custom Report While most users will normally print 824 data using a com puter it 1s possible to print both graphical and tabular data reports directly from the 824 to virtually any serial printer Printouts range from high resolution presentation quality reports when printing to a laser printer because of the instru ment s PDL 3 page description language capabilities to draft quality tabular data reports that can also be printed to a dot matrix printer Connecting the 824 to a Serial Printer Another cable is available for certain printers that have 9 female D connector CBL091 If your printer does not have either of these connectors it is likely not a serial printer Do not attempt to con nect the 824 as damage may result 9 29 09 Make sure the System 824 and your printer are turned off before initiating any of the following steps Step 1 Connect the provided CBL002 serial cable s 8 pin mini DIN connector to the System 824 serial port Step 2 Connect the serial cable s 25 pin male D con nector to your printer s serial port
536. ting is slim this is sufficient range The other 824 Reference Manual 9 29 09 Question 5 Answer 9 29 09 Advanced Time History levels do not have such restrictions Since you can select the main Leq to be A weighted and also enable another A weighted Leq TWA indication in 824 Utility the two levels will be identical except when the main Leq is limited by Start Level When set to 15 dB the lowest time history Leq will be 16 dB due to the fact that the lowest value byte 0 is used as a delimiter in the data structure What is a good value to set Start Level to 15 dB is a good value for most applications since it is just below the thermal noise rating of most condenser and pre polarized microphones If you need to measure lower and have a transducer with a lower noise floor then reduce the value to just below or at the noise floor If you are measuring levels that may be above 143 dB then you will want to raise Start Level to a higher value a 1 4 microphone can measure upward of 160 dB so a Start Level of 35 dB will give a range of 35 dB up to 162 9 dB How are Leq values calculated in the 824 and how 15 that different than traditional non DSP Digital Signal Processor instruments First let s look at the tradition instrument and then the DSP instrument In mixed analog digital instruments such as the LD 870 or 820 or the B amp K 2236 or 2238 Leq is calculated by sampling and integrating the output of
537. tion level press the amp and keys to highlight Cal Level Calibration Step 5 To set the value of the sound level provided by the calibrator press the D key This displays the Cal Level window Calibration Step 6 Then use the 4 D keys to move the cursor position and the amp and W keys to change dig its to enter the proper level Step 7 select the new calibration level press the Y Check key Overview 2 15 Step 8 To verify that the instrument is properly cali brated use the key to highlight Check Calibration Step 9 Place the calibrator over the microphone switch the calibrator ON and press to activate the cal ibration Check process Calibration FL heck 113 18 0 9 Stable The display will show the measured level and the difference from the calibrator level entered and the measured level as shown Step 10 If the calibration is not reasonably close to the level of the calibrator the calibration can be changed by choosing Change Press Y use the W key to highlight Change Calibration Step 11 Switch the calibrator ON and press 2 16 824 Reference Manual 9 29 09 Correction of Calibrator Output Level 9 29 09 The CAL200 provides a nominal pressure level of 94 dB or 114 dB The exact levels are printed on the Larson Davis calibration sheet that is delivered with the calibrator The free field level is 0 12 dB from e
538. tly from the 824 this lets reports to be printed on a nice laser printer connected to a computer without having to disconnect it from the computer X X ISM SSA LOG RTA CANCcel transfer mode 2 in a row ASCII lt CAN gt or CHR 24 Error Messages and Warnings The code listed provided by R98 is the number error messages begin with CHRS 7 ERROR Error Message Code 1 COUNT OVERFLOW 2 EXPONENTIAL OVERFLOW 3 RTX TASK SELECT 4 BAD EXCHANGE RATE 5 UNKNOWN IRQ 6 WATCHDOG RESET 7 RAM BANK 8 OPCODE ERROR 9 29 09 All warning messages begin with CHR 7 WARNING Warning Message Code 128 Out of Memory 129 Divide by Zero 130 Battery Low 131 POWER FAILURE 132 External Power Failure 133 Power Off 134 Time Not Set 135 Timer Pending 136 Printer is Busy 137 DPC Format 138 Key No Effect 139 Stop Required 140 Setting Wrong 141 Overall Reset Required 142 OPEN 143 Already Open 144 No History Yet 145 At End of History 146 At Start of History 147 History Format Bad A 72 824 Reference Manual 9 29 09 148
539. tory if desired Lmax and Lmin are calculated daily and for each hour of the day the hourly Leq EXCD Leq and background Leq Can also show wind or tachometer data using external transducers Metrics Measurement readings adjusted for night and day noise impact differences Adjustments are based on standard nighttime sound penalties criteria 1 e LDN CNEL etc The total exceedance and background Leq metrics are also displayed PassBy Shows the largest single 10 dB passby event detected with its Leq SEL Lmax duration and occurrence date and time Wind Tach Shows wind or tachometer data Current SLM and Overall SLM Views Current SLM clears and starts over when the Reset button is pressed while running Overall SLM does not clear during a reset but continues accumulating data The and W arrow keys be used to cycle between the Current SLM Overall SLM Exposure Ln Centiles and Stats views 9 29 09 The System 824 contains two independent data buffers that can accumulate data separately In essence the instrument becomes two sound level meters in one The data in the primary buffer is referred to as the overall measurement while data in the secondary buffer is referred to as the current measurement The Current SLM and Overall SLM Views have five common displays which can be cycled through using therandlarrow keys Since these displays are identical they will be discus
540. tory Enabled Options add bytes shown if enabled Bytes Basic Daily Record 175 Save Daily Ln Yes 18 Daily Ln Table 440 Enabled by Store Complete Histogram on Daily tab in 824 Utility Wind Tach Yes 19 Table E 3 LOG Memory Use Daily Records Time History Records Time History Enabled Options Hist Resolution Other Level Bytes per record 1 0dB No 1 0 1dB No 2 1 0dB Peak UwPk Max 2 0 1dB Peak UwPk Max 4 Advc 1 plus number of enabled levels Advc 2 plus 2 times each enabled levels Advc Wind Tach Yes 2 Advc Wind Tach Yes 4 Table E 4 LOG Memory Use Time History Records Other Histories and Memory Usage Run Log Histo 20 bytes per record Calibration Log Histo 17 bytes per record LOG File Store with Wind Tach No 7423 each 1 1 1 LOG File Store with Win Tach INo 7423 LOG File Store with Wind Tach Yes 7481 each Table E 5 LOG Memory Use Other Histories and Memory Usage E 2 824 Reference Manual 9 29 09 Estimating Memory Usage The easiest way to estimate the memory usage is to work on a time basis such as one day Estimate how many Exceedances will occur in a normal day Calculate the number of Interval Time History Daily Run Log and Calibration Check records that will be performed in a day Based on the options chosen calculate the number of bytes required for each record
541. tra n the percentage number from 1 to 6 R241 n AUD FFT Total harmonic distortion amp fre see following commands quency R241 AUD FFT Extract harmonic distortion data no output data 512 from FFT Live R241 AUD FFT Extract harmonic distortion data no output data 1024 from FFT Snapshot R241 0 AUD FFT Show precise frequency of funda nnnnnn Hz mental R241 AUD FFT Show level of fundamental nnn n dB 256 R241 n AUD FFT Show distortion of harmonic n n nn n 1 to 20 R241 AUD FFT Show harmonic levels minus funda nnn n dB n 256 mental level n n 1 to 20 R241 AUD FFT Show distortion of harmonic levels n nn n 512 n and above R241 AUD FFT Show distortion of harmonic n nnn n dB n 768 and above minus fundamental level n 1 to 20 24 824 Reference Manual 9 29 09 R241 n 1024 AUD FFT Show noise floor influence indicator for harmonic n n 1 to 20 valleys have less than 10 dB from har monic ec 66 if no influence if influence detected R242 ISM LOG SSA AUD TAL Live Leq detector sample Weight setting applies nnn n dB R243 ISM LOG SSA AUD TAL Live Lmax detector sample Weight and Detector settings apply nnn n dB If f 0 then all 33 filter levels will be output in a comma delimited string f n 0 then all 6 percentages will be output in a comma ANY DATA READ COMMANDS The 824 meas
542. trument on and initiate a single measurement beginning at a certain time on one day and ending at a certain time on the same or another day NOTE If the run time is later than the I Day The timer will automatically turn the stop time then a measurement will start instrument on and initiate one run stop cycle per on the stop date and end at the stop time day from the run date until the stop date on the date AFTER the stop date 2 Day The timer will automatically turn the instrument on and initiate two run stop cycles per day The three enabled modes i e 1 Day 2 Day and Block use the dates set by the Run Date and Stop Date menu items to determine the range of valid days on which to make measurements Run Date Specifies the starting date to take measurements Clock T ate Fun 1224527 LAL AL Stop Date Specifies the date to end the measurement and disable the timer mode Clock Tiner Stop Date 120690 ddd C14 31 7 Run Time 1 Stop Time 1 These settings allow you to specify the beginning and ending times of a measurement 3 26 824 Reference Manual 9 29 09 NOTE If you have selected the Block I Day or 2 Day mode the timer will automatically turn the instrument on one minute prior to the run time Clock Timer Stop Time 1 El ere hh imm ir ces Run Time 2 Stop Time 2 These settings are used to spec ify a second measurement s begi
543. ts the averaging method to be used Linear 824 Reference Manual 9 29 09 The Linear Detector Time will be adjusted to an integer multiple of 0 0025 seconds 2 5mS The Exponential Detector Time multiplied by the Exponential Store Rate gives the total Auto Store time When a condenser microphone is used the 824 requires a stabilization time of approximately 45 seconds before a measurement can be taken 9 29 09 Exponential Linear Detector Time Allows the user to select the averaging time when the linear detector is used Also sets the storage rate for the Autostore ByTime records 0 0025 to 99 9975 seconds Exponential Detector Time When an exponential detector is selected this parameter sets the exponential decay time 1 32 to 64 seconds Exponential Store Rate Selects the rate at which spectral samples are output and stored when the detector is exponential The interval time time between successive samples is equal to the exponential detector time multiplied by the exponential store rate 1 2 1 8 NOTE For example if the detector time is 1 8 and the store rate is 1 2 then the 824 would generate spectra samples at a rate of 16 times per second Transducer Condenser This indicates that the microphone being used 1s an air condenser type and the 824 will generate the appropriate polarization voltage Electret This indicates that the microphone being used is an Electret pre
544. tv Report No Leq SEL Lmin Lmax Peak Uwpk exceedances time date and duration in the short report The Long reports adds the Ln values for the Interval period Hist Report No Leq for each time history period 9 29 09 Printing a Report 8 21 None Enabled Report LOG instrument Print Range Intv Report No You can customize the interval report by choosing the long or short report Lowest Record 00000 Selects the lowest interval record to be printed Highest Record 65535 Selects the highest interval record to be printed Hist Report No You can customize the time history report by choosing the long or short report Lowest Record 00000 Selects the lowest time history record to be printed Highest Record 799999 Selects the highest time history record to be printed Histograms SPL Histogram No You can customize the SPL Histogram report by choosing the long or short report Lowest Level 045 Selects the lowest SPL histogram level to be printed Highest Level 095 Selects the highest SPL histogram level to be printed Resolution 5 0 Selects the SPL histogram resolution Pk 1 Histogram No You can customize the Peak1 Histogram report by choosing the long or short report Lowest Level 110 Selects the lowest Peak histogram level to be printed Highest Level 160 Selects the highest Peak histogram level to be printed
545. ummary Report Template on page 8 8 descriptions of each report for the SSA and LOG instru ments Print Range Excd Report No Short Long Lowest Record Highest Record Intv Report No Short Long Lowest Record Highest Record Hist Report No Yes Lowest Record Highest Record Histograms SPL Histogram No Yes Lowest Level Highest Level Resolution Pk 1 Histogram No Yes Lowest Level Highest Level Resolution Pk 2 Histogram No Yes Lowest Level Highest Level Resolution The following table shows the available options under the Customize menu for the RTA instrument RTA instrument Report Options Description Data Report No Name and Address of Company and date printed Yes Live No Shows beginning and ending date and time runtime type of Averaging sample Yes rate trigger phase ad Live Spectrum Leq No Shows beginning and ending date and time runtime type of Averaging sample Yes rate trigger phase ad Leq Spectrum Max No Shows beginning and ending date and time runtime type of Averaging sample Yes rate trigger phase ad Max Spectrum Min No Shows beginning and ending date and time runtime type of Averaging sample Yes rate trigger phase ad Min Spectrum 8 26 824 Reference Manual 9 29 09 RTA instrument Autostore Rpt No The Short report prints the Lmax and Lmin spectrum I
546. und made by other people In every case noise involves the judgment of someone and puts noise in the realm of psychology not physics Rules 1 Use word sound to describe measurements to remove the emotional overtones associated with the word noise Some sound metrics use noise in their name and it is proper to use the name as it is Sound Exposure SE Sound Exposure Level SEL Let D 18 It is the total sound energy of the actual sound during a specific time period It is expressed in Pascals squared seconds T SE p tdt T where pa is the sound pressure and is the Measurement Duration specific time period When applied to hearing damage potential the equation 1s changed to SE tico ar where is the Exposure Factor See Exchange Rate Standard ANSI 51 25 The total sound energy in a specific time period The equation for it is T SEL 10108 2 The sound pressure is squared and integrated over a specific period of time this is called the sound exposure and has the units Pascal squared seconds or Pascal squared hours PO is the reference pressure of 20 uPa and is the reference time of 1 second It 1s then put into logarithmic 824 Reference Manual 9 29 09 Sound Pressure 9 29 09 form It is important to note that it is not an average since the reference time is not the same as the integration time The physical characteristic
547. ur measurement Date Format Displays the date in Normal or ISO 8601 format Normal has the form of ddmmmyyyy and ISO 8601 has the form yyyymmmdd where dd is the two digit date of the month 1 to 31 mmm is the month i e JAN and yyyy is the year 1 e 2000 Takt Enables Takt functionality to give you taktmaxmal values Press 4 twice to exit the menu Pressing the D key again moves to the About c screen The following screen appears About Instruments 55 FET A ke ISH oO AUD demos re LOG o TAL use n EHN DSP e Wind gt Front Panel Keys Functions and Menus 3 21 Calibration The About c display shows the system s currently available instruments Additional instruments can be added to the Sys tem 824 through firmware upgrades as they become avail able Checked instruments are installed and available for use The number of demos used is indicated Only 20 demos are allowed When demos used equals 20 options not pur chased are no longer available for use If you have found them useful they can be installed permanently without restrictions Call Larson Davis for details To calibrate the System 824 or to view previous calibration information use the W key to select Calibration from the Tools menu then press key The following screen appears Date and time of the last calibration The level detected during the last check
548. ures We would like the microphone to measure sound pressure force per unit area instead of sound force If the pressure is applied uniformly over the microphone diaphragm a simple constant the diaphragm area relates the two but 1f the pressure varies across the diaphragm the relationship is more complex For example if a negative pressure 1s applied on one half the diaphragm and an equal positive pressure is applied to the other half the net force is zero and essentially no motion of the diaphragm occurs This occurs at high frequencies and for specific orientations of the microphone Rules 1 Do not use a microphone at frequencies higher than specified by the manufacturer to increase the frequency response choose smaller microphones 2 Choose a microphone for free field or random incidence to minimize the influence of orientation A microphone influences the sound being measured The microphone measures very small forces low level sound can run about one billionth of a PSI Every measurement instrument changes the thing being measured and for very small forces that effect can be significant When sound impinges directly on a microphone the incident wave must be reflected since it cannot pass through the microphone This results in the extra force required to reflect the sound and a microphone output that is higher than would exist 1f the microphone were not there This is more important at high frequencies and when the microphone is
549. ures SPL data with three frequency weightings and with three time weighting detectors simultaneously as well as peak and integrated levels with frequency weightings To access this additional data use these Read Commands using the second operand indicated SSA ISM LOG and ENV instruments only R 4x SSA ISM LOG Current SPL Any Wght nnn n dB Dect R 9 w SSA ISM LOG OVERALL TWA Any Wght nnn n dB R 11 w SSA ISM LOG CURRENT Any Wght nnn n dB R 13 w SSA ISM LOG OVERALL SEL Any Wght nnn n dB 9 29 09 A 25 R14 w SSA ISM LOG CURRENT SEL Any Wght nnn n dB 15 x SSA ISM LOG OverAll Minimum Any Wght nnn n dB Level Dect R 16 x SSA ISM LOG OverAll Lmin Date Any Wght ddmmmyy hh mm ss and Time Dect 17 x SSA ISM LOG Current Minimum Any Wght nnn n dB Level Dect 18 x SSA ISM LOG Current Lmin Date Any Wght ddmmmyy hh mm ss and Time Dect R 19 x SSA ISM LOG OverAll Maximum Any Wght nnn n dB Level Dect R 20 x SSA ISM LOG OverAll Lmax Date Any Wght ddmmmyy hh mm ss and Time Dect 21 SSA ISM LOG Current Maximum Any Wght nnn n dB Level Dect R 22 x SSA ISM LOG Current Lmax Date Any Wght ddmmmyy hh mm ss and Time Dect R23 w SSA ISM LOG OverAll Pk Level Any Wght nnn n dB R24 w SSA ISM LOG OverAll Lpk Date
550. us indicator Run 2d Bn sn 55 Time History RECORD 3 OF B3 190 gt Stop 1 ED 55 Time History RECORD aH F B3 190 Pause iu BD ED 55 Time History RECORD 24 OF Bi 190 Cont Key BD 55 Time History RECORD iz OF B3 190 gt 120 Mark 22 r Har kz a0 Identifies the marker L mutembls o 9 29 09 System 824 Views 5 17 TH represents time history which is the TH setup in the settings menu Use the up and down W arrow keys to view each level selected in the TH setup 5 18 The following discusses each of these display components Display label This shows the current display in this example SSA Time History Leq reading at cursor Displays the current Leq of the time history period This level is also shown graphically Time cursor Record number The Time cursor the vertical bar allows you to scroll graphically through the history of the displayed measurement readings using the arrow keys Notice that as you move back and forth in time that the record number changes The total number of records is also shown Time history graph Shows the history of Leq readings Time increases towards the right of the display Value of other level This shows the value of the other levels selected in the TH setup Other level This shows all of the levels selected in the TH setup in the settings menu Status indicator
551. ut getting into the fine details of operating the System 824 let s just press some keys and see what it can measure and display Step 1 Let s look at the SLM amp RTA SSA ID Access the Setup Menu by pressing O and use W and keys to highlight the SLM amp RTA ID as shown below P Lodging LOG Step 1 With SLM amp RTA highlighted press Y to select it as the current ID Step 2 Press RUN STOP key D to begin a measure ment and obtain a display resembling the follow ing a inn a0 Le 2 5 Overview 2 7 The large numerals represent the SPL measurement taken with the Slow detector and the A weighting In the lower left 18 an indication of the Leq value and the elapsed time of the measurement for which the Leq value is calculated The graph being traced across the display is a time history of the SPL value Stop Pause and Back Erase Functions Stopping and Starting Measurements Pausing Measurements Back Erasing While taking a measurement you can stop pause and back erase To stop the measurement press the key Restart by pressing I To pause the measurement press the Il PAUSE key To continue the measurement press the key a second time While paused the and keys can be used to move a cursor across the time history and display the SPL and secondary parameters as measured at any particular time during the measurement period Should an unwanted s
552. ve states Stop Ready Armed Triggered Ended Use the table below to determine how these will be set up Ended Triggered Armed Ready Stop 16384 8192 2048 1024 256 128 64 32 16 8 4 2 1 Heat Cal Heat Cal Heat Cal Logic Cal Logic Heat Cal Logic Out Out Out The default setting indicates the following Ended state is output on logic out Triggered state is output on logic out Armed state is output on cal Ready state is output on heat Stop state is not output For more information on the Control Connector see the section System 824 Components on page 1 10 9 29 09 The default setting is 04768 which is shown by the bolded squares in the table above The Logic output is on pin 2 of the control connector and will be driven to 5 volts through a 1000 ohm resistor when asserted or zero volts when not asserted Pin 1 1s the ground signal The Cal output is on pin 7 of the control connector and will be driven to 5 volts through a 10 000 ohm resistor when asserted and to zero volts when not asserted The Heater control output is on pin 8 of the control connector and will conduct current to ground when asserted and not conduct when not asserted uses an open drain N channel transistor Maximum voltage is 40 VDC and 0 5 optional 11 15 VDC and the maximum current is 100 mA Return current path is through pin 1 control ground RT60 Rev
553. wer right corner of the display as shown below SLY SFL Slow 68 The upper and lower limits of sound pressure level which can be measured for each of these scales are indicated in the RMS Measurement Range LOG and ISM modes only on page C 11 Performing a Sound Level Measurement 9 9 Selecting the Range Setting SSA Mode 9 10 When the range is highlighted as shown in the above graphic the range can be toggled between Normal and Low by pressing the P keys If the approximate level is known select the range setting for which that level falls nearest the middle of the measurement range If it 1s not known select the Normal range which is usually adequate for the majority of common measurements The range setting can also be selected using the setup menu In fact this is the only way to select the High range Press the key the P key highlight SLM press the 7 key highlight Range and press the key to obtain the following display Highlight the desired range and press the key to make the selection The SSA Mode has a smaller measurement range than the ISM and LOG Modes As a result rather than select a range setting from among three choices as done for the ISA and LOG Modes we will select a gain value which can range from 20 to 50 dB in steps of 10 dB The usual practice is to set the gain to 0 dB and later modify that as required to obtain a good measurement without overload or
554. will be consumed in order to download data before the memory capacity is reached The information in this Appendix will be useful to accomplish this task Memory usage for the LOG and SSA instruments will be presented separately An example in the form of a Memory Usage Worksheet will be included for the LOG instrument LOG Memory Usage Each of the 824 s History Functions use space out of a common memory The amount each record takes is based on the options selected The following information is provided to assist in determining the amount of data that can be stored according to the option desired The example will be show assuming that all of the memory is available for one measurement though many measurement files may be stored at one time Exceedance Records Exceedance History Enabled Options add bytes shown if enabled Basic Exceedance Record Excd Time Hist Y es Ten sample prior to and up to ten followingthe ewent will be stored Binary Accumulator and Count Enabled by Store Complete Histogram on Daily tab in 824 Ltilit Wind Tach Y es Table E 1 LOG Memory Use Exceedance Records 9 29 09 E 1 Interval Records Intv History Enabled Options add bytes shown if enabled Basic Interval Record Intv Save Ln s Yes Intv Ln Table 384 Enabled by Store Complete Histogram setting on Interval tab of 824 Utility 2 Table E 2 LOG Memory Use Interval Records Daily Records Daily His
555. window the sound pressure level builds up rapidly wind noise since most of the pressure changes are to move the air and very little of it compresses the air to create sound Persons not far way can hardly hear what you hear The acoustic near field 15 characterized by pressures that do not create sound that can be measured in the far field Therefore measurements made here are not useful in predicting the sound levels far way or the sound power of the source Geometric Near Field The distance from a source of sound is less than the largest dimension of the sound source In the near field effect of source geometry is significant Sound sources often have a variety of specific sources within them such as exhaust and intake noise When in the near field the sound of a weaker but close source can be louder than that of a more distant but stronger source Therefore measurements made here can be used to separate the various sources of sound but are not useful in predicting the sound levels and sound spectrum far from the source Typically it is unwanted sound This word adds the response of humans to the physical phenomenon of sound The descriptor should be used only when negative effects on people are known to occur Unfortunately this word is used also to describe sounds with no tonal content random Ambient The all encompassing sound at a given location caused by all sources of sound It is generally random but need not be N
556. y W B Fundamental frequency 246 186 5Hz n 1 86 34 amp dB THD n dB down Harmonic percentiles 4th and higher percentiles 9 29 09 2nd BH 288 58 30B t ya monic dB down 3rd 3 48 ndp amp 24th 64 6dB 4th amp higher harmonics The THD display provides harmonic distortion measurements of an audiometer and its phones The FFT capabilities of the 824 are used to measure the fundamental level fundamental frequency and harmonics THD data is output in dB down from the fundamental level and in percent The display also shows the level and frequency of the fundamental An asterisk following a THD percentage indicates that influences of system noise floor are present Results are reported in dB down difference and units of percentile The dB down difference is calculated by subtracting the harmonic level from the fundamental level The percentage is equal to one hundred times ten raised to AUD Optional 13 19 Entering the THD display will auto position the cursor to the fundamental frequency on the FFT screen The THD as calculated in the 824 satisfies all of the requirements for ANSI S3 6 13 20 the power of the result of the dB down difference divided by twenty THD is calculated by scanning the full spectrum to find the fundamental frequency and selecting the highest peak The actual frequency is extrapolated from the fundamental bin frequency and the highest sideband b
557. y and highlight the Edit Settings menu option Press the 7 TOOLS key to display the fol lowing screen With the Setup Tools menu you can create and or modify instrument definition ID settings The Setup Tools menu provides the following three options which are later described in greater detail 9 29 09 Front Panel Keys Functions and Menus 3 15 Save ID Title ID Name Menu Items Description Save ID Saves Creates an ID Title Description of ID ID Name Name of ID The Save ID menu item saves or creates an ID Use 43 or keys to highlight Save ID then press Y You will then be prompted to verify the name for the ID See ID Name below You can attach a description to your ID with the Title menu item This description can be used on printed reports and other items The Title field is capable of holding up to 30 characters You use the JD Name menu item to give an ID a unique name that represents the ID in the Setup menu The JD Name field is capable of holding up to 8 characters Name format The first 8 characters form the name and the last three are the extension that indicate the instrument type e g SSA The name does not have to be a full 8 characters long Leading spaces and symbols will be removed from a name Case is preserved but ignored when finding names Embedded spaces will be converted to under score The name should start
558. y of the wind speed tach signal from the external transducer Limits to parameters associated with this factor are as follows Max Input Freq 25000 Hz Max Display Value 65535 units Min Input Freq 1 Hz Resolution Min Display Value 0 01 units Using ID Setting Files 7 27 Wind Units Direction Units 7 28 Examples Type Speed Frequency Wind Scale YOUNG Wind Sentry 400 0 mph 235 Hz 1 7 YOUNG Wind Monitor 400 0 mph 1825 Hz 0 22 1 pulse rev 30000 rpm 500 Hz 60 16 pulse rev 30000 rpm 8000 Hz 3 75 600 pulse rev 2500 rpm 25000 Hz 0 10 Wind Units is a four character alphanumeric field e g mph m s ft s etc Direction Units are used for describing Wind Direction or Throttle Position There are five options available Compass Compass reports wind direction using the following sixteen ordinate points N NNE NE ENE E ESE SE S SSW SW WSW W WNW NW NNW Degrees Degrees reports wind direction in degrees from 0 to 360 Percent Percent would typically be used to report throttle position over the range 0 to 100 as a percent of full throttle Voltage Voltage reports this parameter as a DC voltage over the range 0 to 2 49 volts Number Number reports this parameter in numeric form between 0 and 255 93 824 Reference Manual 9 29 09 Wind Tach Enable Note that when the Wind Tach feature is enabled Ln will automatically be enabled as well When this occurs the message Setting Conflict
559. y trigger or run if Triggering is off otherwise they will accumulate for each R S measurement until manually reset Max The Max spectrum shows the maximum level obtained by each filter and the maximum broadband Flat level This 18 a bin by bin maximum level The Max spectrum is reset by a current or overall reset and the R S key when Autostore is enabled Display Label _ RTA i20 Filter level in dB gt 184 3 1DD Bandwidth 1 1 or 1 3 oct X Selected filter frequency 14 G Hz Re Leq spectrum s duration gt 10 1000 1 1 octave cursor RTA optional 11 21 Once in a display view you can simply use the up and W down arrow keys to move between the views 11 22 Min The Min spectrum shows the minimum level obtained by each filter along with the minimum broadband Flat level This is a bin by bin minimum level The Min spectrum is reset by a current or overall reset and the R S key when Autostore is enabled Display label Filter level in Bandwidth 1 1 or 1 3 oct 3 Selected filter frequency 1 Leq spectrum s duration _ gt _ 10 1000 Tm gt RTA pes a 1 1 octave cursor Times The Times display shows the
560. z produces a change of 0 3 dB SPL passes Class 1 according to IEC 61672 Vibration Sensitivity worst case 73 7 dB with linear weighting at 1 0 m sec referenced to 58 1 dB Warm up Time 45 sec Digital Display Update Rate Four times per second 0 25 sec between updates First display indication is available 0 25 seconds after initiation of a measurement Effect of an extension cable EXAxxx on calibration none up to 500 feet 824 Reference Manual 9 29 09 ACIDC Output AC output voltage 3 Volts peak range DC output voltage 0 to 3 Volts range SPL Start level Vo 0 028 SPL Vox 002842 Start level AC DC output 600 Ohms AC ouput error 0 1 dB for input impedance impedances 52 K Ohms instrument readings are not affected by AC or DC output loading AC DC output con 3 5mm stereo jack nector Power Supply Batteries 3 AA alkaline cells or NiMH battery pack Internal charge time DC power input approx 7 10 hours BATO10 2300 mAH pack approx 6 hours 010 1200 mAH pack depending on capacity at time of charge 6 15 Volts at 1 2 amp max Typical DC power 150 mA 0 12 Volts DC power connector 5 5mm x 2 5mm coaxial power plug C 6 Battery Operating Time full capacity continuous operation reference environmental conditions individual cells may vary in performa

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