User`s Guide Digital Sound Level Meter Model 407750
Contents
1. Speech 1 Large Office Residence Sound studio 407750 EN v2 2 07 13 Battery Replacement When the low battery message appears on the LCD the 9V battery has fallen to a critically low voltage level and should be replaced as soon as possible The battery compartment cover resides at the rear of the meter Remove the rear battery compartment screw and remove the battery compartment cover change the battery and replace the compartment cover 8 407750 EN v2 2 07 13 Warranty FLIR Systems Inc warrants this Extech Instruments brand device to be free of defects in parts and workmanship for one year from date of shipment a six month limited warranty applies to sensors and cables If it should become necessary to return the instrument for service during or beyond the warranty period contact the Customer Service Department for authorization Visit the website www extech com for contact information A Return Authorization RA number must be issued before any product is returned The sender is responsible for shipping charges freight insurance and proper packaging to prevent damage in transit This warranty does not apply to defects resulting from action of the user such as misuse improper wiring operation outside of specification improper maintenance or repair or unauthorized modification FLIR Systems Inc specifically disclaims any implied warranties or merchantability or fitness for a specific purpose and will not be liable2. REC key The REC indicator will appear on the LCD Once the REC key is pressed the meter begins tracking the highest MAX and lowest MIN readings Press the REC again and the MIN indicator will appear on the LCD along with the lowest sound level reading since the REC key was pressed Press the REC again and the MAX indicator will appear along with the highest reading the meter has encountered since the REC key was first pressed Press and hold the REC until the REC indicator extinguishes to exit the RECORD mode 4 407750 EN v2 2 07 13 BA Background Noise Absorber Mode The Background Noise Absorber allows the user to accurately measure equipment noise by eliminating background noise The Sound Level Meter first stores the background noise as a reference level From there when a sound is measured the display will show the sound level measurement minus the background noise To operate the meter in BA mode follow these steps 8 Bly OT Be Gon NS Power the meter Press the MAXHLD key the MAX HOLD icon will appear on the LCD Press the BA key F will appear to the left of the SPL display icon Press the MAX HOLD key again the MAX HOLD icon will reappear on the LCD The meter is now displaying the background reference noise Power the device under test and note the new sound level meter reading If the reading changes the new reading is the sound level of the device If the reading does not change the noise produc
3. for any direct indirect incidental or consequential damages FLIR s total liability is limited to repair or replacement of the product The warranty set forth above is inclusive and no other warranty whether written or oral is expressed or implied Calibration Repair and Customer Care Services FLIR Systems Inc offers repair and calibration services for the Extech Instruments products we sell NIST certification for most products is also provided Call the Customer Service Department for information on calibration services available for this product Annual calibrations should be performed to verify meter performance and accuracy Technical support and general customer service is also provided refer to the contact information provided below Support Lines U S 877 439 8324 International 1 603 324 7800 Technical Support Option 3 E mail support extech com Repair amp Returns Option 4 E mail repair extech com Product specifications are subject to change without notice Please visit our website for the most up to date information www extech com FLIR Commercial Systems Inc 9 Townsend West Nashua NH 03063 USA ISO 9001 Certified Copyright 2013 FLIR Systems Inc All rights reserved including the right of reproduction in whole or in part in any form www extech com 9 407750 EN v2 2 07 13
4. on the display release the MAX HOLD and then the ON OFF key The Auto Power Off feature is now disabled Note that the Auto Power Off feature is re activated the next time the meter is powered down 5 407750 EN v2 2 07 13 Analog Outputs The meter includes an AC and a DC analog output These outputs are proportional to the displayed sound level and are ideal for use with chart recorders and dataloggers The AC output is 0 707V rms full scale and the DC output is 10mV per dB The labeled 3 5mm output mini plugs are located on the bottom of the instrument RS 232 Output The meter includes an RS 232 PC interface jack This PC interface allows the meter to store and display readings on a PC as they are recorded The interface cable and software for data acquisition are sold separately Detailed instructions are provided with the software 6 407750 EN v2 2 07 13 Reference Information Frequency Weighting Characteristics Frequency Hz A Weighting C Weighting Tolerance IEC 651 Type 2 30448 26 2dB 0 8dB 2dB 16 1dB 0 2dB 1 5dB ee e 1 5dB o j o 8 SES 1k 1dB 0 8dB 1 5dB 3dB na oa TE Typical A Weighted Sound Levels 50HP Siren 100 Jet takeoff 200 Riveting machine Subway 20 Pneumatic drill 50 Vacuum cleaner 10 Large store Small office Night residential area Whisper 5 0 Threshold of hearing Chain saw Boiler room Freight train 100
5. EXTECH ee INSTRUMENTS Digital Sound Level Meter Model 407750 EXTECH 407750 ao 20 0 gg Pf ee so mk Ji stow T CAL g REC MAX HOLD MIN DOSE PEAK Digital Sound Level Meter with RS2332 C A BAMODE F S DOWN BACKLIT UPPER Introduction Congratulations on your purchase of the Extech 407750 This device measures sound level in dB and the measurement range can be set automatically or manually The 407750 offers selectable frequency weighting A and C and Time Response Fast and Slow The built in RS 232 PC interface allows the user to record readings onto a PC in real time Careful use of this meter will provide years of reliable service Specifications Display Backlit 2000 count LCD with analog bargraph Display update rate Main LCD digits 0 5 seconds Bargraph 50mS Analog Bargraph 1dB steps with 50dB display range Microphone Electret condenser 0 5 diameter Measurement Bandwidth 31 5Hz to 8KHz Measurement Range A weighting 30 to 130dB C weighting 35 to 130dB 6 ranges in 10 dB steps 30 to 80dB 40 to 90dB 50 to 100dB 60 to 110dB 70 to 120dB 80 to 130dB Accuracy Resolution 1 5dB 0 1dB Time response selections Fast 125ms and Slow 1 second AC and DC Analog outputs 0 707VAC rms at full scale 10mVDC dB 3 5mm output jacks Standards Meets ANSI and IEC Type 2 External Calibrator Extech model
6. ed from the device is either equal to or less than the background noise Press the BA key again to return to the normal mode of operation Auto and Manual Ranging The meter powers up in the Automatic Range mode In automatic mode the meter automatically finds the correct range in order to produce the best accuracy However if it is desired to set the range manually follow these steps 1 2 Power the meter Notice the two 2 digit number to the immediate left of the analog bargraph This number is the low end of the presently selected range see the specifications for the ranges To change the range press the UP key to raise the range or press the DOWN key to lower the range The two digit number on the left of the bargraph will change with each key press An advantage of Manual mode is that it takes less time for the meter to take a reading In Auto Range mode the meter must first locate the correct range before displaying a measurement LCD Backlighting Press the BACKLIT key to illuminate the LCD The backlight will remain on for 5 seconds and then automatically switch off to preserve battery life Auto Power Off To preserve battery life this meter has an automatic power off feature If the unit is not used for approximately 20 minutes the meter shuts off To override this function follow these steps 1 2 3 From a power OFF condition press and hold the ON OFF and MAX HOLD keys simultaneously When n appears
7. s 407766 or 407744 Power 9V Battery 20 hour battery life typical with low battery indication Dimensions weight 3 2 x 10 1 x 1 5 80 x 256 x 38mm 8 5 oz 240g 2 407750 EN v2 2 07 13 Meter Description 1 LCD Display 2 Microphone 3 ON OFF key 4 REC Record key 5 MAXHLD Max Hold key 6 C A Weighting Select key 7 BA Background Absorber key 8 F S Fast Slow Response select key 9 DOWN 10 Backlit LCD backlighting key 11 UPPER 12 AC adaptor jack 13 Calibration screw adjust 14 AC analog output jack 15 DC analog output jack 16 RS 232 output jack Sooo 0 0 f e P A TK BAMODE F S 12 13 14 15 16 Note The Battery Compartment and the Threaded Tripod mount access are located on the back of the instrument not pictured 407750 EN v2 2 07 13 Operation Quick Start 1 Power the meter by pressing the ON OFF key 2 The meter s LCD will count down to zero 99 9 88 8 77 7 etc and then begin measuring sound levels If the LCD does not switch on after pressing the ON KEY check the 9V battery 3 Point the microphone toward the source of the sound level to be measured and view the reading on the meter s LCD A and C Frequency Weighting Select A or C weighting via the C A key The LCD will reflect the currently selected frequency weighting Use A weighting to have the meter respond as the human ear would
8. with regard to frequency response the human ear boosts and cuts amplitude over the frequency spectrum A weighting is used for environmental measurements OSHA regulatory testing law enforcement and workplace design Select C weighting for flat responding measurements less amplitude boost or cut across the frequency spectrum C weighting is used in applications where hearing conservation is not an issue for example in the diagnosis of malfunctions in electrical electronic and mechanical devices FAST SLOW Response Time Select either FAST 125ms response or SLOW 1 second response measurements by pressing the F S key The LCD will reflect the currently selected mode Selection of Fast or Slow is determined by the application and any directives or standards related to that application For example most hearing conservation or OSHA related testing is done using SLOW and A weighting MAX HOLD The meter is capable of taking continuous measurements and only updating the LCD when a higher reading than the one presently on the display is detected The bargraph display continues to change while the main LCD waits for a higher reading Press the MAXHLD key to activate the MAX HOLD mode The LCD will reflect the MAX HOLD function Press the MAXHLD key again to return to normal operation Record REC Function To Record the Maximum and Minimum sound level measurements over a programmable period of time press the
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