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7381 Users Guide 681..

1. Adj RO I SET EXIT ALPHA lt SET ALPHA Adj SET EXIT ES only HGb on HGb Po Power Menu SET Cutout Reset Mode SET EXIT SET EXIT Cooling Mode SET EXT SET EXIT SET EXIT SET EXIT Figure 5 Controller Operation Flowchart 38 Menu Probe L gt Operating up gt Serial uP IEEE 488 UP Menu 4 DOWN Parameters bown Interface DOWN Interface lt DOWN lt SET BAUD Rate a SET EXIT Sample Period EXI T Duplex Mode SET EXI T Linefeed j SET EXIT L Menu SET Y i i n 1 i T i 1 i i Device i Address 1 i 1 n n i i 1 i n i n 1 n i SET EXIT EOS I SET EXIT IEEE 488 Option Installed DO NOT CHANGE THESE VALUES SEE
2. Ending temperature Tg 300 C Starting temperature T 25 C Ending depth Dg 9 2 inches Dg 9 2 0 00077 300 25 1 7 59 inches Electrical Resistivity Electrical resistivity describes how well the fluid insulates against the flow of electric current In some applications such as measuring the resistance of bare temperature sensors it may be important that little or no electrical leakage oc cur through the fluid In such conditions choose a fluid with very high electrical resistivity Fluid Lifetime Many fluids degrade over time because of vaporization water absorption gel ling or chemical break down Often the degradation becomes significant near the upper temperature limit of the fluid substantially reducing the fluid s lifetime Safety When choosing a fluid always consider the safety issues associated Obviously where there are extreme temperatures there can be danger to personnel and equipment Fluids may also be hazardous for other reasons Some fluids may be considered toxic Contact with eyes skin or inhalation of vapors may cause injury A proper fume hood or adequate ventilation system must be used if haz ardous or bothersome vapors are produced WARNING Fluids at high temperatures may pose danger from BURNS FIRE and TOXIC FUMES Use appropriate caution and safety equip ment Fluids may be flammable and require special fire safety equipment and proce dures An important characteristic o
3. Table 4 Typical Proportional Band Settings for Various Fluids Fluid Temperature Proportional Band Stability Water 30 C 0 31 C 0 003 C Water 60 C 0 31 C 0 003 C Eth Gly 50 35 C 0 31 C 0 005 C Eth Gly 50 60 C 0 31 C 0 005 C Eth Gly 50 100 C 0 4 C 0 010 C Oil 200 10cs 35 C 0 6 C 0 004 C Oil 200 10cs 60 C 0 6 C 0 004 C Oil 200 10cs 100 C 0 6 C 0 004 C Oil 710 200 C 0 4 C 0 008 C The proportional band adjustment may be accessed within the secondary menu Press SET and EXIT to enter the secondary menu and show the heater power Then ET SET to access the proportional band El ex Access heater power in secondary menu Pb 0 To change the proportional band press UP or DOWN fond Decrement display Pb 0 060 i New proportional band setting To accept the new setting and access the cutout set point press SET Pressing EXIT will exit the secondary menu ignoring any changes just made to the proportional band value SET Accept the new proportional band setting 47 7381 Calibration Bath User s Guide 48 9 10 Cutout As a protection against software or hardware fault shorted heater triac or user error the bath is equipped with an adjustable heater cutout device that shuts off power to the heater if the bath temperature exceeds a set value This protects the heater and bath materials from excessive temperatu
4. 11 7381 Calibration Bath User s Guide 3 2 Environmental Conditions Although the instrument has been designed for optimum durability and trou ble free operation it must be handled with care The instrument should not be operated in an excessively dusty or dirty environment Maintenance and clean ing recommendations can be found in the Maintenance Section of this manual The instrument operates safely under the following conditions e temperature range 5 40 C 41 104 F e ambient relative humidity maximum 80 for temperatures 31 C de creasing linearly to 50 at 40 C e pressure 75kPa 106kPa e mains voltage within 10 of nominal e vibrations in the calibration environment should be minimized e altitudes less than 2000 meters e indoor use only 4 Quick Start Unpacking 4 4 1 4 2 Quick Start A CAUTION Read Section 6 entitled BATH USE before placing the bath in service This chapter gives a brief summary of the steps required to set up and operate the bath This should be used as a general overview and reference and not as a substitute for the remainder of the manual Please read Section 5 Installation through Section 8 General Operation carefully before operating the bath Unpacking Unpack the bath carefully and inspect it for any damage that may have oc curred during shipment If there is shipping damage notify the carrier immedi ately Verify that all components are present
5. Hart Scientific 9 Z381 Calibration Bath User s Guide Rev 681505 Rev 681505 Limited Warranty amp Limitation of Liability Each product from Fluke s Hart Scientific Division Hart is warranted to be free from defects in mate rial and workmanship under normal use and service The warranty period is one year for the Calibration Bath The warranty period begins on the date of the shipment Parts product repairs and services are warranted for 90 days The warranty extends only to the original buyer or end user customer of a Hart authorized reseller and does not apply to fuses disposable batteries or to any other product which in Hart s opinion has been misused altered neglected or damaged by accident or abnormal conditions of operation or handling Hart warrants that software will operate substantially in accordance with its func tional specifications for 90 days and that it has been properly recorded on non defective media Hart does not warrant that software will be error free or operate without interruption Hart does not warrant calibra tions on the Calibration Bath Hart authorized resellers shall extend this warranty on new and unused products to end user customers only but have no authority to extend a greater or different warranty on behalf of Hart Warranty support is available if product is purchased through a Hart authorized sales outlet or Buyer has paid the applicable international price Hart reserves the right
6. QUENTIAL DAMAGES OR LOSSES INCLUDING LOSS OF DATA WHETHER ARISING FROM BREACH OF WARRANTY OR BASED ON CONTRACT TORT RELIANCE OR ANY OTHER THEORY Since some countries or states do not allow limitation of the term of an implied warranty or exclusion or limitation of incidental or consequential damages the limitations and exclusions of this warranty may not apply to every buyer If any provision of this Warranty is held invalid or unenforceable by a court of com petent jurisdiction such holding will not affect the validity or enforceability of any other provision Fluke Corporation Hart Scientific Division 799 E Utah Valley Drive e American Fork UT 84003 9775 e USA Phone 1 801 763 1600 Telefax 1 801 763 1010 E mail support hartscientific com www hartscientific com Subject to change without notice e Copyright O 2005 Printed in USA Table of Contents 1 Before You Start l 1 1 Symbols Used o cu see css om sm ee 1 1 2 Safety Information 2 1 2 1 WARNINGS et caos iaci Bae He ae ees ee Sik a al oe n 2 1 2 2 CAUTIONS 4X iua a cel a doc od 4 1 3 Authorized Service Centers ooo e 5 2 Introduction 9 3 Specifications and Environmental Conditions 11 3 1 OpeciicationS 2 2445 Sa opo P PAR AS B RO ROBUR OEE ES 11 3 2 Environmental Conditions 12 d Quick Stall aa ow Re Re eee re Wee f
7. The various commands for accessing the bath controller functions via the digi tal interfaces are listed in this section see Table 5 starting on page 62 These commands are used with both the RS 232 serial interface and the IEEE 488 GPIB interface In either case the commands are terminated with a carriage re turn character The interface makes no distinction between upper and lower case letters hence either may be used Commands may be abbreviated to the minimum number of letters which determines a unique command A command may be used to either set a parameter or display a parameter depending on whether or not a value is sent with the command following a character For example an s lt cr gt returns the current set point and an s 50 00 lt cr gt sets the set point to 50 00 degrees In the list of commands characters or data within brackets and J are op tional for the command A slash denotes alternate characters or data Nu meric data denoted by n may be entered in decimal or exponential notation Characters are shown in lower case although upper case may be used Spaces may be added within command strings and will simply be ignored Backspace BS ASCII 8 may be used to erase the previous character A terminating CR is implied with all commands 10 Digital Communication Interface Cooling Control 10 4 Cooling Control The 7381 bath has a fully automated refrigeration contro
8. Used to display the next parameter in a menu and to set parameters to the displayed value DOWN Used to decrement the displayed value of parameters UP Used to increment the displayed value EXIT Used to exit from a menu When EXIT is pressed any changes made to the displayed value will be ignored 3 The on off switch controls power to the entire bath including the stirring motor 4 The control indicator is a two color light emitting diode LED This indica tor lets the user visually see the ratio of heating to cooling When the indicator is red the heater is on and when it is green the heater is off and the bath is cooling 23 7381 Calibration Bath User s Guide 24 7 2 7 3 5 The cooling switch turns on the refrigeration for control below 50 C and rapid cool down The cooling shuts off automatically above 60 C Manually turn off the refrigeration at temperatures where it has been determined to be un necessary See Sections 8 6 Refrigeration 9 13 2 Cooling Mode and 9 13 3 Hot Gas Bypass Mode Refrigeration Condenser Access Door Located on the bottom front of the instrument is a refrigeration condenser ac cess door Hinged on the right side the door is opened by gripping the left side and pulling outward This access to the condenser coil is provide so the user can keep the condenser fins clean allowing unimpeded air flow insuring the condenser functions effi ciently Both the vents in the door a
9. When uncrating the bath remove all of the accessories from the packing foam around the bath Remove the pre formed foam Gently ease the bath from the crate using the casters to roll the bath If it is required to lift the bath slightly to release it from the crate two people should carefully slide their hands under the bath and gently lift the bath only enough to clear the packing foam and roll the bath from the crate The area containing the compressors will be heavier than the rest of the bath If it is required to move the bath after installation empty the bath of fluid DO NOT move a bath filled with fluid Unlock the casters and roll the bath Do not attempt to carry the bath It is tall and heavy and is not provided with han dles Personal injury or damage to the bath may occur Bath Environment The Model 7381 Bath is a precision instrument which should be located in an appropriate environment The location should be free of drafts extreme temper atures and temperature changes dirt etc The surface where the bath is placed must be level Provide at least 6 inches 15 cm of clearance around the instru ment to allow sufficient air circulation The top surface of the bath may become hot at high temperatures Beware of the danger of accidental fluid spills A fume hood or other adequate ventilation system should be used to remove any vapors given off by hot bath fluid Silicone oils require additional ventila tion to prevent an
10. 10 Digital Communication Interface Serial Communications 10 10 1 Digital Communication Interface The 7381 bath is capable of communicating with and being controlled by other equipment through the digital interface Two types of digital interface are avail able the RS 232 serial interface which is standard and the IEEE 488 GPIB in terface which is optional With a digital interface the bath may be connected to a computer or other equipment This allows the user to set the bath temperature monitor the tem perature and access any of the other controller functions all using remote com munications equipment In addition the cooling may be controlled using the interface To control the cooling with the interface the cooling power switch must be ON Serial Communications The RS 232 serial interface allows serial digital communications over fairly long distances 15 24 meters With the serial interface the user may access any of the functions parameters and settings discussed in Section 9 Controller Op eration with the exception of the baud rate setting The serial interface operates with eight data bits one stop bit and no parity 57 7381 Calibration Bath User s Guide 10 1 1 Wiring The serial communications ca E ble attaches to the bath through RS 232 Cable Wiring for the DB 9 connector on the back IBM PC and Compatibles of the instrument Figure 7 shows the pin out of this con n
11. Auto Set Cool mode to Off cololj of f co of Set Cool mode to On co ol on co on Set Cool mode to Auto co ol au to co au Read HGb mode hg b hg hgb xxx hgb auto Set HGb mode hg b of f on au to On Off Auto Set HGb mode to Off hg b of f hg of Set HGb mode to On hg b on hg on Set HGb mode to Auto hg bj a uto hg au Read HGb power p wm p pwm 75 Set HGb power P wm n p 31 Oto 100 Read low set point limit value tllow tl tl 999 tl 40 Set low set point limit to n tllow n tl 40 60 to 20 Read high set point limit value th igh th th 999 th 150 Set high set point limit to n th igh n th 150 150 to 30 Miscellaneous not on menus Read all extended parameters all all list of extended parameters Read firmware version number ver sion ver ver 9999 9 99 ver 7381 1 00 Read all operating parameters all all list of operating parameters Read structure of all commands h elp h list of commands Legend Optional Command data Returns either information n Numeric data supplied by user 9 Numeric data returned to user x Character data returned to user Note When DUPLEX is set to FULL and a command is sent to READ the command is returned followed by a carriage return and linefeed Then the value is returned as indicated in the RETURNED column 64 11 Calibration Procedure Calibration Points 11 11 1 11 2 11 3 Calibration Procedure In some instances the user may want to c
12. C ethanol 0 007 C at 100 C 5012 oil Heating Timet 60 minutes from 25 C to 100 C 5012 oil 230V Cooling Time lt 6 hours from 25 C to 80 C ethanol Stabilization Time 15 20 minutes Temperature Setting Digital display with push button entry Set point Resolution 0 01 0 00018 in high resolution Display Temperature Resolution 0 01 Digital Setting Accuracy 1 C Digital Setting Repeatability 0 01 C Heater 700 Watts 230V Nominal Access Opening 6 8 x 4 7 172 x 119 mm Immersion Depth 18 457 mm without liquid in glass thermometer cal kit 19 482 mm with liquid in glass thermometer cal kit Wetted Parts 304 Stainless Steel Powert 230 VAC 10 60 Hz 10 5 A 2430 VA 230 VAC 10 50 Hz 10 5 A 2430 VA optional Note If the voltage is outside 10 the compressor may be dam aged Check the back panel label for the correct voltage and frequency prior to energizing the instrument System Fuse 15A 250V slow blow Volume 4 2 gal 15 9 liters Weight 200 Ib 91 kg Size w x f b x h 14 W x 31 D x 42 H 356 x 788 x 1067mm 37 940 mm from floor to tank access opening Safety OVERVOLTAGE Installation CATEGORY Il Pollution Degree 2 per IEC 1010 1 Refrigeration R 507 first stage R 508b second stage Interface Package RS 232 included IEEE 488 optional Rated at listed 230 V
13. If the mode is set to RESET the heater only comes on again when the temperature is reduced and the cutout is manually reset by the oper ator see Section 9 10 Cutout Check that the cutout set point is ad justed to 10 or 20 C above the maximum bath operating temperature and that the cutout mode is set as desired e fthe cutout activates when the bath temperature is well below the cutout set point or the cutout does not reset when the bath tempera ture drops and it is manually reset then the cutout circuitry or the cutout thermocouple sensor may be faulty or disconnected Contact an Authorized Service Center see Section 1 3 on page 5 for assis tance 71 7381 Calibration Bath User s Guide 72 Problem Causes and Solutions The display flashes cutout and an incorrect process temperature The problem may be that the controller s voltmeter circuit is not func tioning properly A problem could exist with the memory back up battery If the battery voltage is insufficient to maintain the memory data may become scrambled causing problems A nearby large static discharge may also affect data in memory Verify that the parameters on the Report of Test are accurate Cycle the power off disconnect the bath from AC and then restart the bath If the problem reoccurs the battery should be replaced Contact an Authorized Service Center see Section 1 3 on page 5 for assis tance If initializing the me
14. Note The cooling capacity of the system can exceed the capacity of the heater at higher temperatures The HGb parameter is indicated by 51 7381 Calibration Bath User s Guide 52 9 14 Auto i HGb mode is set for automatic operation A E Swa ke KWE SERE RIEN DE To change to On or Off mode press DOWN until the desired mode appears and then press SET to accept the change Pressing EXIT will ignore any changes made and exit to the menu HGb mode set to on HGb mode set to off The percent of power control is viewed on the display Po after the mode se lection has been set The Po for the Auto mode will be a value automatically selected by the temperature controller It is not adjustable by the user The Po in the Off mode is shown as 0 The Po in the On mode must be selected by the user The value is increased with the UP button and decreased by the DOWN button The parameter is indicated by A O Po 65 j Current power value shown To change the value when in the HGb On mode press UP or DOWN until the desired value is reached Press SET again to have the value accepted or EXIT to discard any changes made and exit to the menu Serial Interface Parameters The serial interface menu is accessed by pressing UP from the operating pa rameters menu The serial RS 232 interface parameters menu is indicated by SErIRL i Serial RS 232 interface parameters menu The serial
15. ae AB 4 1 Unpacking 2223 been ee Oe LESS 13 42 Set UP x sexum sa EG RUE AUR X SEGUE EE ES Kae And 13 4 3 POWef 546 wed 3 Es ge 46444 34 15 4 4 Setting the Temperature e sss llle 15 5 Installation 17 5 1 Moving or Uncrating the Bath 17 3 2 Bath Environment enn 17 3 3 Tipping Prevention Bracket Installation 17 5 331 Installation On A Wood Floor 2 2 0 2 0 0 000000008 18 53 Installation On a Concrete Floor lee 18 5 33 Installation Of The Bath css ek mr d Res 18 5 4 Dry out Perl d zu ec a e RR EE A ves 19 3 5 Bath Preparation and Filling 19 5 6 POWET 2 eo poke d RE GR Se e x 9o bab E S ee m e oos 20 6 Bath Uses it 84 9 a om exc eer e LL 6 1 General 4 sy cg ee Ae ME exe Xu ede RU d 21 6 2 Comparison Calibration o 21 6 3 Calibration of Multiple Probes 22 7 Parts and Controls 23 ii 7 1 7 2 7 3 7 4 Front Control Panel o 23 Refrigeration Condenser Access Door 24 Bath Tank and Lad cuerdas ee G 24 BACK Panel azar asi an RA E aS ake es RAD a bas 25 TAA Fluid Expansion Reservoir o L L L L ee nn 25 8 General Operation 27 8 1 8 2 8 3 8 4 8 5 8 6 Heat Transfer Fluid llle 27 8 1 1 Temperature RANSE 0 a a Bee
16. set points and have the instrument automatically cycle between the tempera tures holding at each for a length of time The user can select one of four dif ferent cycle functions The program parameter menu is accessed by pressing SET and then UP Program menu Press SET to enter the program menu SET Enter program menu 9 Controller Operation Ramp and Soak Program 9 6 1 9 6 2 9 6 3 Number of Program Set points The first parameter in the program menu is the number of set points to cycle through Up to 8 set points can be used in a ramp and soak program These set points are independent from the programmable set points described in Sec tion 9 3 1 Programmable Set points MG stensuesatasesnassucerscacseansuest Paz3 New number of program set points ARTO Press SET to continue Press EXIT to ignore any changes and to continue SET Save new setting Set points The next parameters are the program set points Masieususeseastaassugeetassenneenes NRREREKEERRRASENERERBRSRAEREERRERRE c 40 00 New set point value sua Sreuauesauasesesaucctacntereseues Press SET to save the new set point value The other set points can also be set in the same manner Once the set points are programmed as desired press EXIT to continue fexr Continue to next menu function Program Soak Time The next parameter in the program menu is the soak time This is the time in minutes
17. that each program set point is maintained after settling before pro ceeding to the next set point The duration is counted from the time the temper ature reaches the set point 43 7381 Calibration Bath User s Guide 44 9 6 4 9 6 5 NUSEEEARESNEKSENENVAR SEXEEEEERREE RE Press SET to continue SET Save new setting Program Function Mode The next parameter is the program function or cycle mode There are four pos sible modes which determine whether the program scans up from set point 1 to n only or both up and down from set point n to 1 and also whether the program stops after one cycle or repeats the cycle indefinitely Table 3 below shows the action of each of the four program mode settings Table 3 Program Mode Setting Actions Function Action 1 up stop 2 up down stop 3 up repeat 4 up down repeat OO mm Press SET to continue SET Enter program menu Program Control The final parameter in the program menu is the control parameter Three op tions are available for controlling the ramp and soak program The options are to start the program from the beginning 60 continue the program from where it was when it was stopped o nt or stop the program OFF Pr 0FF Program presently off NIN 9 Controller Operation Secondary Menu 9 7 9 8 9 9 Use the UP or DOWN buttons to change the status Pr Cont Start cycle from beginnin
18. 30 0 0 086 Wi 80 0 30 0 0 00385 0 0038416 Figure 8 Calibration Example 67 12 Maintenance 12 Maintenance The calibration instrument has been designed with the utmost care Ease of op eration and simplicity of maintenance have been a central theme in the product development Therefore with proper care the instrument should require very little maintenance Avoid operating the instrument in dirty or dusty environments e A battery is used to maintain operating parameters in the unit All operat ing parameters including calibration parameters should be checked on a regular basis to insure accuracy and proper operation of the instrument See the troubleshooting section for the procedure on checking the status of the battery e If the outside of the bath becomes soiled it may be wiped clean with a damp cloth and mild detergent Do not use harsh chemicals on the sur face which may damage the paint e Periodically check the fluid level in the bath to ensure that the level has not dropped If the fluid level is too low the stability may be affected Changes in fluid level are dependent upon several factors specific to the conditions in which the equipment is used Therefore the bath should be checked weekly and adjustments made as required A WARNING Before servicing the instrument disconnect the power mains e Periodically remove the top cover of the bath and wipe out oil around the outside of the g
19. A 27 8 1 2 MISCOSILY ai ye aveai reet e A dw it E Ier di 27 8 1 3 Specific Heat sss oso eR wp ub Se fe A fa a he we eel a 27 8 1 4 Thermal Conductivity e o oa Rm Roo wd acs Re m eum f Je 28 8 1 5 Thermal Expansion ss fe wi aie 4 6 ded a aki Bed HE RO A A ES n 28 8 1 6 Electrical ResiS vIty sss m nest o x x daye te a ea NS 29 8 1 7 Fluid Lifetime 4 4 Res xXx xe mU d Rok ORS eg 29 8 1 8 Safety usse ence aee ox Dogs ed mem qo dor e de ue Glade ow 29 8 1 9 Costa x don d m tad e Sea eonim dux b pude 30 8 1 10 Commonly Used Fluids soes ei 00 09 Ree ae R EG EEG 30 814101 Walles eris ko er dii eom Penge de Re Ron fer ae ke 30 8 1 10 2 Ethylene Glycolie ef ue Rey Sh ARDEN S edt e deir ode a a 30 S1103 Mineral Oil ona mp Up EUR RR EU RR SE RON UR DU Soe AR A 30 ATOU Silicone Oll Juss wld aly mile me RR VW Susi ea le Dee E e le le GI nove 31 8 1 11 Fluid Characteristics Charts ee 31 8 1 11 1 Limitations and Disclaimer ee ee 31 SLIL Aboutthe Chart qs ane ein we ack Bio svete le Re GC DE BUR Ye Ho Pla wee A 31 SUNS oro Rog e ce end Mayne A Rue SRS ee ca BS 34 li C Se ot af dit api vip te A ta a kh ee we oe Aye 34 Heaters aie bea eh bd b 9 9 o9 oe om SOE EES Had 9 34 Temperature Controller ee ee ee 35 Refrigeration iud eg Sh er Sola E SR Se SR 35 9 Controller Operation 37 9 1 9 2 9 5 9 4 95 9 6 Bath Iemperat te ss lt co s pie ee ee eRe ee ee 37 Res
20. C v 130 C fl cc 133 C 5 25 C 0 92 25 C 0 4 0 00028 25 C 0 00105 1000 25 C 200 05 5010 10 150 C Silicone Oil Type 30 C v 209 fl cc 211 C 10 25 C 0 934 25 C 043 40 C 0 00032 25 C 0 00108 1000 25 C 200 10 5012 3 135 C 0 45 100 C 50 150 C 0 482 200 C Silicone Oil Type 10 C v 230 C fl cc 232 C 200 25 C 0 949 25 C 0 370 Q40 C 0 00034 25 C 0 00107 1000 25 C 200 20 5013 0 393 100 C 50 150 C 0 420 200 C Silicone Oil Type 30 C v 278 C fl cc 280 C 50 25 C 0 96 25 C 0 4 0 00037 25 C 0 00104 1000 25 C 200 50 5014 50 150 C Silicone Oil Type 70 C v 230 C fl cc 232 C 50 70 C 1 07 25 C 0 358 40 C 0 00035 25 C 0 00075 100 25 C 550 5016 300 C fl oc 10 104 C 0 386 100 C 1 150 C 0 433 200 C Silicone Oil Type 80 C v 300 C fl oc 302 C 50 80 C 1 11 25 C 0 363 40 C 0 00035 25 C 0 00077 100 25 C 710 5017 7 204 C 0 454 100 C 1 150 C 0 505 200 C Silicone Oil Type 66 C v 313 C fl oc 315 C 50 66 C 0 96 25 C 0 34 100 C 0 0003 0 00095 100 25 C 210 H 14 204 C 1 150 C Heat Transfer Salt 180 C fr 550 C NONE 34 150 C 2 0 150 C 0 33 0 0014 0 00041 1 7 Q cm 5001 6 5 300 C 1 9 300 C 2 4 500 C 1 7 500 C Limiting Factors b boiling point Very low water solubility ice will form as a slush from condensation below freezing e hig
21. IEC 61000 4 2 If the instrument is subjected to ESD conditions the instrument may require the user to cycle the power to return to normal operation 13 Troubleshooting Comments 13 2 1 2 13 2 2 Emission Testing The instrument fulfills the limit requirements for Class A equipment but does not fulfill the limit requirements for Class B equipment The instrument was not designed to be used in domestic establishments Low Voltage Directive Safety In order to comply with the European Low Voltage Directive 73 23 EEC Hart Scientific equipment has been designed to meet the IEC 1010 1 EN 61010 1 and the IEC 1010 2 010 EN 61010 2 010 standards 75
22. Read ALPHA calibration al pha al al 9 9999999 al 0 0038573 parameter Set ALPHA calibration parameter al pha n al 0 0038433 00370 to 0039999 ton Operating Parameters Menu Read cutout mode cm ode cm cm xx cm auto Set cutout mode cm ode r eset a uto RESET or AUTO Set cutout to be reset cmlode r eset cm r manually Set cutout to be reset cm ode a uto cm a automatically Serial Interface Menu Read serial sample setting sa mple sa sa 9999 sa 1 Set serial sampling setting ton sa mple n sa 0 0 to 4000 seconds Set serial duplex mode du plex f ull h alf FULL or HALF Set serial duplex mode to full du plexi ftuil du f Set serial duplex modeto du plex h arf du h half Set serial linefeed mode Iffeed on of f ON or OFF Set serial linefeed mode to Ifleedi on If on on Set serial linefeed mode to fleed offf If of off Calibration Menu Read CO calibration parameter b0 b0 b0 9 9999 b0 0 0002 Set CO calibration parameter to n b0 n b0 0 Unlimited 63 7381 Calibration Bath User s Guide Interface Command Summary Continued Command Command Returned Command Description Format Example Returned Example Acceptable Values Read CG calibration parameter bg bg bg 999 99 bg 406 25 Set CG calibration parameterto n bg n bg 406 25 Unlimited Read Cool mode co ol co CO XXX co auto Set Cool mode co ol of f on au to On Off
23. User s Guide 70 If a hazardous material is spilt on or inside the equipment the user is re sponsible for taking the appropriate decontamination steps as outlined by the national safety council with respect to the material MSDS sheets ap plicable to all fluids used in the baths should be kept in close proximity to the instrument If the mains supply cord becomes damaged replace it with a cord of the appropriate gauge wire for the current of the bath If there are any ques tions call an Authorized Service Center see Section 1 3 on page 5 for more information Before using any cleaning or decontamination method except those rec ommended by Hart users should check with an Authorized Service Cen ter see Section 1 3 on page 5 to be sure that the proposed method will not damage the equipment If the instrument is used in a manner not in accordance with the equip ment design the operation of the bath may be impaired or safety hazards may arise The over temperature cutout should be checked every 6 months to see that it is working properly In order to check the user selected cutout follow the controller directions in Section 9 2 Reset Cutout for setting the cut out Both the manual and the auto reset option of the cutout should be checked Set the bath temperature higher than the cutout Check to see if the display flashes cutout and if the temperature is decreasing Note When checking the over temperature cutout be sure
24. and heat capacity which make it among the best fluids for good control stability at lower temperatures Temperature stability is much poorer at higher temperatures because water condenses on the lid cools and drips into the bath Water is safe and relatively inert The electrical conductivity of water may prevent its use in some applications Water has a limited tempera ture range from a few degrees above 0 C to a few degrees below 100 C At higher temperatures evaporation becomes significant Water used in the bath should be distilled or deionized to prevent mineral deposits Consider using an algicide chemical in the water to prevent contamination Note Water used at temperatures greater than 75 C 167 F may have stability problems Ethylene Glycol The temperature range of water may be extended by using a solution of one part water and one part ethylene glycol antifreeze The characteristics of the ethylene glycol water solution are similar to water but with higher viscosity Use caution with ethylene glycol since this fluid is very toxic Ethylene glycol must be disposed of properly Mineral Oil Mineral oil or paraffin oil is often used at moderate temperatures above the range of water Mineral oil is relatively inexpensive At lower temperatures mineral oil is quite viscous and control may be poor At higher temperatures vapor emission becomes significant The vapors may be dangerous and a fume hood or adequate ventilation syst
25. controller hardware configuration This data is used in some circumstances for diagnostic purposes Heater The temperature controller precisely controls the bath heater to maintain a con stant bath temperature Power is controlled by periodically switching the heater on for a certain amount of time using a solid state relay The front panel red green control indicator shows the state of the heater The control indicator glows red when the heater is on and green when the heater is 8 General Operation Temperature Controller 8 5 8 6 off The indicator pulses at a constant rate when the bath is maintaining a stable temperature Temperature Controller Hart Scientific s unique hybrid digital analog temperature controller controls the bath temperature The controller offers the tight control stability of an ana log temperature controller as well as the flexibility and programmability of a digital controller The bath temperature is monitored using a platinum resistance sensor as the control probe The signal is electronically compared with the programmable reference signal amplified and then passed to a pulse width modulator circuit that controls the amount of power applied to the bath heater The bath is opera ble within the temperature range given in the specifications For protection against a solid state relay failure or other circuit failure the micro controller automatically turns off the heater with a second mechanical
26. description of the problem 2 Introduction Introduction The Hart Scientific s 7381 is a compact constant temperature bath useful in temperature calibration and other applications requiring stable temperatures An innovative state of the art solid state temperature controller has been incor porated which maintains the bath temperature with extreme stability The tem perature controller uses a micro controller to execute the many operating functions User interface is provided by the 8 digit LED display and four key switches Digital remote communications is standard with an RS 232 and optional with an IEEE 488 interface The 7381 bath was designed to be compact and low cost without compromising performance The 7381 bath operates over a wide temperature range from 80 C to 110 C The refrigeration permits sub ambient temperature control The 7381 features e Rapid heating and cooling e RS 232 standard and IEEE 488 optional e Temperature scan rate control e Ramp and soak functions e Compact size e Eight set point memory e Adjustable readout in C or F e Automatic refrigeration control 3 Specifications and Environmental Conditions Specifications 3 1 Specifications and Environmental Conditions Specifications Range 80 C to 110 C Stability 2 sigma 0 006 C at 80 C ethanol 0 005 C at 0 C ethanol 0 005 C at 110 C 5012 oil Uniformity 0 007 C at 80 C ethanol 0 007 C at 0
27. dirty en vironments reduce the lifetime of the instruments electrical components Table 2 and Figure 4 on pages 32 and 33 have been created to provide help in selecting a heat exchange fluid media for your constant temperature bath These charts provide both a visual and numerical representation of most of the physical qualities important in making a selection The list is not all inclusive There may be other useful fluids not shown in this listing The charts include information on a variety of fluids which are often used as heat transfer fluid in baths Because of the temperature range some fluids may not be useful with your bath Limitations and Disclaimer The information given in this manual regarding fluids is intended only to be used as a general guide in choosing a fluid Though every effort has been made to provide correct information we cannot guarantee accuracy of data or assure suitability of a fluid for a particular application Specifications may change and sources sometimes offer differing information Hart Scientific cannot be liable for any personal injury or damage to equipment product or facilities resulting from the use of these fluids The user of the bath is responsible for collecting correct information exercising proper judgment and insuring safe operation Operating near the limits of certain properties such as the flash point or viscos ity can compromise safety or performance Your company s safety policies re gar
28. e 7381 Bath e Access Hole Cover e Fluid Expansion Reservoir with Cover e User s Guide e RS 232 Cable e Report of Test e Drain Valve e 9930 Interface it Software and User s Guide e Tipping Prevention Bracket including mounting hardware for wood or concrete floor e 2019 DCB Kit Liquid in Glass LIG Adapter and Carousel optional e 2069 Scope Liquid in Glass LIG with mounts optional If you are missing any item please call an Authorized Service Center To locate an Authorized Service Center near you see Section 1 3 on page 5 Set Up WARNING The instrument is equipped with a soft cutout user settable firmware and a hard cutout set at the factory Check the flash point boiling point or other fluid characteristic applicable to the circumstances of the instrument operation Ensure that the soft cutout is adjusted to the fluid characteristics of the application As a guideline the soft cutout should be set 10 C to 15 C below the flash point of the bath fluid See Section 8 1 Heat Transfer Fluid for specific information on bath fluids and Section 9 10 Cutout 13 7381 Calibration Bath User s Guide 14 Set up of the bath requires careful unpacking and placement of the bath filling the bath with fluid and connecting power Consult Section 5 Installation for detailed instructions for proper installation of the bath Be sure to place the bath in a safe clean and level location Refer to Section 5 3 Tipp
29. interface parameters menu contains parameters which determine the operation of the serial interface The parameters in the menu are baud rate sample period duplex mode and linefeed 9 Controller Operation Serial Interface Parameters 9 14 1 9 14 2 9 14 3 Baud Rate The baud rate is the first parameter in the menu The baud rate setting deter mines the serial communications transmission rate The baud rate parameter is indicated by bAUG Serial baud rate parameter Press SET to choose to set the baud rate The current baud rate value will then be displayed 1200 b Current baud rate The baud rate of the bath serial communications may be programmed to 300 600 1200 or 2400 baud Use UP or DOWN to change the baud rate value 2400 b New baud rate Press SET to set the baud rate to the new value or EXIT to abort the opera tion and skip to the next parameter in the menu Sample Period The sample period is the next parameter in the serial interface parameter menu The sample period is the time period in seconds between temperature measure ments transmitted from the serial interface If the sample rate is set to 5 the bath transmits the current measurement over the serial interface approximately every five seconds The automatic sampling is disabled with a sample period of 0 The sample period is indicated by SAMPLE j Serial sample period parameter Press SET to choose to set th
30. of about 2 minutes If a fault condition exists upon appli cation of power the bath will not energize Under and Over Voltage Protection at 230 VAC Voltage Cutout 12 5 203 257 VAC Voltage Cut In 7 5 213 247 VAC Authorized Service Centers Please contact one of the following authorized Service Centers to coordinate service on your Hart product Fluke Corporation Hart Scientific Division 799 E Utah Valley Drive American Fork UT 84003 9775 USA Phone 1 801 763 1600 7381 Calibration Bath User s Guide Telefax 1 801 763 1010 E mail support hartscientific com Fluke Nederland B V Customer Support Services Science Park Eindhoven 5108 5692 EC Son NETHERLANDS Phone 3 1 402 675300 Telefax 31 402 675321 E mail ServiceDesk fluke nl Fluke Int l Corporation Service Center Instrimpex Room 2301 Sciteck Tower 22 Jianguomenwai Dajie Chao Yang District Beijing 100004 PRC CHINA Phone 86 10 6 5 12 3436 Telefax 86 10 6 5 12 3437 E mail xingye han fluke com cn Fluke South East Asia Pte Ltd Fluke ASEAN Regional Office Service Center 60 Alexandra Terrace 03 16 The Comtech Lobby D 118502 SINGAPORE Phone 65 6799 5588 Telefax 65 6799 5588 E mail antngOsinga fluke com When contacting these Service Centers for support please have the following information available 1 Before You Start Authorized Service Centers Model Number Serial Number Voltage Complete
31. of the fluid must be considered since the in crease in fluid volume as the bath temperature increases may cause overflow It may be dangerous to permit the fluid to overflow the tank It may also cause loss of valuable bath fluid Excessive thermal expansion may also be undesir able in applications where constant liquid level is important Thermal expansion coefficients of several fluids are shown in Table 2 on page 32 Fluid manufacturers can also provide this information The thermal expan sion coefficients are shown in units of cm cm C However the values are the same for any unit of length Divide the value by 1 8 for F coefficients The fol lowing equation may be used to find the desired depth Dg Ds K T Ts 1 Or Ds Dg K Tp Tg 1 where Dg The Maximum Fill Depth Where K Expansion coefficient Tg Ending temperature Tg Starting temperature D Ending depth Dy Starting depth The maximum fill depth is typically 0 5 to 0 8 inches below the level of the gasket at the top of the bath tank not the top of the bath lid Judgement must be made with different stirring arrangements to prevent splashing on the gasket or lid of the bath Example The final depth of Dow Corning 710 silicone oil in the bath tank is to be 9 2 inches when heated from 25 to 300 C What should the starting depth be Expansion coefficient for 710 oil on Table 2 K 0 00077 inch inch C 8 General Operation Heat Transfer Fluid 8 1 7
32. of the most recent Report of Test to restore the test pa rameters DO NOT operate this instrument in an excessively wet oily dusty or dirty environment Silicone oils require additional ventilation to prevent an oily dirty environment Most probes have handle temperature limits Be sure that the probe handle temperature limit is not exceeded in the air above the instrument The instrument and any thermometer probes used with it are sensitive in struments that can be easily damaged Always handle these devices with care Do not allow them to be dropped struck stressed or overheated COLD BATHS Refrigerated baths require that the condensing coil be cleaned periodi cally Accumulation of dust and dirt on the condenser will result in pre mature failure of the compressor This bath has been equipped with a brownout and over voltage protection device as a safety feature to protect the system components Mode of Operation This bath needs to be plugged into the line voltage for at least 2 minutes before operation This is only necessary for the first time the bath is energized or when it is moved from one location to an other Turning the bath ON or OFF does not trigger the delay If a High Low voltage condition exists for longer than 5 seconds the bath de energizes An amber indicator on the back panel lights when this con dition exists Re energization is automatic upon correction of the fault condition and af ter a delay cycle
33. oily dirty environment Tipping Prevention Bracket Installation In order to create the safest possible conditions under use your bath comes equipped with a tipping prevention bracket The installation of the bracket is re quired for compliance with the international safety standard IEC 1010 1 Sec tion 7 3 Stability that applies to the stability of the bath under normal operating conditions 17 7381 Calibration Bath User s Guide 5 3 1 5 3 2 5 3 3 Installation On A Wood Floor The wood floor installation kit includes lag bolts Drill three 1 8 inch x 1 inch deep approximately 3 mm x 25 5 mm pilot holes using the tipping bracket to mark the hole placement Use the lag bolts to install the bracket to the floor Ensure that the bracket is installed in such a way that the bath will have a mini mum 6 inches of clearance for air circulation See Figure 2 Screw the bracket securely to the floor Wall Caster Slots Figure 2 Tipping Prevention Bracket Installation Installation On a Concrete Floor Using a concrete drill and concrete drill bit drill three 4 inch x 1 1 4 inch deep approximately 6 5 mm x 32 mm holes in the concrete floor using the bracket to mark the hole placement Drop the flare anchor bolt into the hole Tightening the screw expands the anchor in the drilled hole and secures the tipping bracket Ensure that the bracket is installed in such a way that the bath will have a minimum of 6 inc
34. probe erroneous data in memory may be the cause Re initialize the memory as discussed in the problem The display flashes cutout and an incorrect process temperature If the problem remains the cause may be a defective electronic compo nent contact an Authorized Service Center see Section 1 3 on page 5 for assistance 13 Troubleshooting Troubleshooting Problem Causes and Solutions The controller controls or at tempts to control at an inaccurate temperature The controller operates normally except when controlling at a speci fied set point At this set point the temperature displayed does not agree with the temperature measured by the user s reference ther mometer to within the specified accuracy This problem may be caused by an actual difference in temperature between the points where the control probe and thermometer probe measure tempera ture by erroneous bath calibration parameters or by a damaged con trol probe e Check the vernier setting for the setpoint e Check that the bath has an adequate amount of fluid in the tank and that the stirrer is operating properly e Check the resistance between the pins and the sheath of the probe They shoulld be open e Check that the thermometer probe and control probe are both fully inserted into the bath to minimize temperature gradient errors e Check that the calibration parameters are all correct according to the Report of Test If not re program t
35. rere ree rer ct Cooling Mode The cooling mode determines whether refrigeration is in Auto mode On or Off Normally the cooling mode is set to Auto mode In the Auto mode the re frigeration is On below approximately 60 C Note If the fluid is cooling from above 60 C the refrigeration turns on at approximately 59 C If the fluid is heating from below 60 C the refrigeration shuts off at 60 C If the set point is more than 5 C higher than the current bath temperature the refrigeration will automatically shut off until needed to maintain the temperature selected There may be times when Auto mode is undesirable In that case the refrigeration may be set to On or Off When the refrigeration is set to On or Off the refriger ation is on or off for all temperatures CAUTION The refrigeration may be damaged or the lifetime shortened if used above 60 C for more than one hour The parameter is indicated by 9 Controller Operation Operating Parameters 9 13 3 Auto j Cooling mode set for automatic To change to On or Off mode press DOWN until the desired mode appears and then press SET n i Cooling mode set to on A OFF Cooling mode set to off Individual steps may be skipped by pressing EXIT Hot Gas Bypass Mode The hot gas bypass HGb system is a method of reducing cooling or refrigera tion capacity Reducing cooling capacity helps improve temperature stability in the bath and reduces ener
36. that the temperature limits of the bath fluid are not exceeded Exceeding the temperature limits of the bath fluid could cause harm to the operator lab and instrument When using silicon oil the bath will require periodic maintenance The silicon oil will condense on the bath during normal operation due to the outgasing of the oil How often and how long the bath is operated at higher temperatures determines how often the maintenance will have to be performed Simply wipe down the oily areas of the bath with a mild degreaser such as 409 Do not spray the degreaser directly on the bath Spray the degreaser on a cloth and wipe the bath down with the cloth Re peat the process as often as necessary to keep the oil from collecting on the bath If oil is allowed to collect on the bath it may run into the bath and collect on the interior of the bath causing internal damage that may affect the lifetime of the instrument 13 Troubleshooting Troubleshooting 13 13 1 Troubleshooting This section contains information on troubleshooting CE Comments and a wiring diagram This information pertains to a number of bath models and cer tain specifics may not pertain to your model Troubleshooting In the event that the instrument appears to function abnormally this section may help to find and solve the problem Several possible problem conditions are described along with likely causes and solutions If a problem arises please read this s
37. the overflow tube level The fluid expansion reservoir is stainless steel with an aluminum heat shield to prevent touching when the tank is hot There is a stainless steel dust cover over the reservoir with an elbow on top that the drain tube is inserted into The reser voir hangs on a hook and is attached to the bath with a thumbscrew A WARNING The drain tube and dust cover may be hot Always be sure the drain tube is fully inserted into the elbow of the dust cover To drain fluid from the reservoir first remove the dust cover and set aside Then undo the thumbscrew and carefully lift it with the two handles provided on the back The fluid may then be poured back into the bath when it is cooler or poured into some other approved container Caution Be careful when han dling hot fluids burns can result When the excess fluid has been removed re verse the process to replace the reservoir and dust cover Always wipe away spilt fluid if spilling occurs WARNING The overflow tube is not large enough to handle large flow rates encountered by overfilling the tank It is intended for expanding fluid rates from heating only Fill only until the level reaches the top of the stir baffle see Figure I on page 14 25 8 General Operation Heat Transfer Fluid 8 1 General Operation Heat Transfer Fluid Many fluids will work with 7381 bath Choosing a fluid requires consideration of many important characteristics of the fluid Among
38. these are temperature range viscosity specific heat thermal conductivity thermal expansion electri cal resistivity fluid lifetime safety and cost Temperature Range One of the most important characteristics to consider is the temperature range of the fluid Few fluids work well throughout the entire temperature range of the bath The temperature at which the bath is operated must always be within the safe and useful temperature range of the fluid used The lower temperature range of the fluid is determined either by the freeze point of the fluid or the temperature at which the viscosity becomes too great The upper temperature is usually limited by vaporization flammability or chemical breakdown of the fluid Vaporization of the fluid at higher temperatures may adversely affect temperature stability because of cool condensed fluid dripping into the bath from the lid The bath temperature should be limited by setting the safety cutout see Section 9 10 Cutout or the high limit see Section 9 16 Calibration Parameters so that the bath temperature cannot exceed the safe operating temperature limit of the fluid Viscosity Viscosity is a measure of the thickness of a fluid or how easily it can be poured and mixed Viscosity affects the temperature uniformity and stability of the bath With lower viscosity fluid mixing is better This creates a more uniform temperature throughout the bath This improves the bath response time allow
39. tional band setting function press SET fex Return to temperature display Proportional Band In a proportional controller such as this the heater output power is proportional to the bath temperature over a limited range of temperatures around the set point This range of temperature is called the proportional band At the bot tom of the proportional band the heater output is 100 At the top of the pro 45 7381 Calibration Bath User s Guide 46 portional band the heater output is 0 Thus as the bath temperature rises the heater power is reduced which consequently tends to lower the temperature back down In this way the temperature is maintained at a fairly constant temperature The temperature stability of the bath depends on the width of the proportional band see Figure 6 If the band is too wide the bath temperature deviates ex cessively from the set point due to varying external conditions This is because the power output changes very little with temperature and the controller cannot respond very well to changing conditions or noise in the system If the propor tional band is too narrow the bath temperature may swing back and forth be cause the controller overreacts to temperature variations For best control stability the proportional band must be set for the optimum width Wy Proportional Band too Narrow Proportional Band too Wide Optimum Proportional Band el Figure 6 Bath Temperature Fluctuation At Va
40. to invoice Buyer for importation costs of repairs replacement parts when product purchased in one country is submitted for repair in another country Hart s warranty obligation is limited at Hart s option to refund of the purchase price free of charge re pair or replacement of a defective product which is returned to a Hart authorized service center within the warranty period To obtain warranty service contact your nearest Hart authorized service center or send the product with a description of the difficulty postage and insurance prepaid FOB Destination to the nearest Hart au thorized service center Hart assumes no risk for damage in transit Following warranty repair the prod uct will be returned to Buyer transportation prepaid FOB Destination If Hart determines that the failure was caused by misuse alteration accident or abnormal condition or operation or handling Hart will provide an estimate or repair costs and obtain authorization before commencing the work Following repair the product will be returned to the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges FOB Shipping Point THIS WARRANTY IS BUYER S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IM PLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE HART SHALL NOT BE LIABLE FOR ANY SPECIAL INDIRECT INCIDENTAL OR CONSE
41. 0 j Current vernier value in C To adjust the vernier press UP or DOWN Unlike most functions the ver nier setting has immediate effect as the vernier is adjusted SET need not be pressed This allows the bath temperature to be continually adjusted as it is displayed Increment display 0 00090 j New vernier setting il 9 Controller Operation Scan 9 4 9 4 1 9 4 2 Next press EXIT to return to the temperature display or SET to access the temperature scale units selection SET Access scale units Scan The scan rate can be set and enabled so that when the set point is changed the instrument heats or cools at a specified rate degrees per minute until it reaches the new set point With the scan disabled the instrument heats or cools at the maximum possible rate Scan Control The scan is controlled with the scan on off function that appears in the main menu after the set point function ScRn zO0FF Scan function off ScRnz n i Scan function on Press SET to accept the present setting and continue SET Accept scan setting Press exit until the bath temperature is displayed The controller should always be left in the main temperature display menu while in the scan mode Viewing other menus will cause the controller to halt scanning while in the menu Nor mal scanning will resume once the menu has been exited back to the displayed temperature Scan Rate The next function
42. 2 JEEE 488 Communication optional 59 10 2 1 CUP dp acku ue Ron AR tse ame M dee dor wo ae qon Mop 59 10 2 1 1 IEEE 488 Address wi ki ne noon tet goo Oe ORO OR NON Rp l z j n 60 10 2 1 2 Transmission Termination ve v ata G04 soe al fake a da a m RR ew 60 10 2 2 TEEE 488 Operation s pen w we kou am w o won een 60 10 3 Interface Commands 60 10 4 Cooling Control os ss ee eee n E PE 61 lii 11 Calibration Procedure 6 11 1 Calibration PointS non 65 11 2 Measuring the Set point Error 65 11 3 ComputingROand ALPHA 65 11 4 Calibration Example llle 66 12 Maintenance 69 13 Troubleshooting 6 66 6 sss eee eee m n 71 13 1 Troubleshooting se sae e ee ot moo xy 71 13 2 Comments sog w 4 4 den bay dy f n die oso Pe ORO Oe ok a ee 8 TA 13 2 1 EMC Directive i ca gue UE Ry Yee eod Wi eed Veo Se 74 18 21 11 Imiuunity Tes tin ges qbot kantin kc p ne ee emet es Ree ds qw e ARTE ae 74 TIAL Emission Testing 45 as eas ve ei SOR Sw we EUR Rk we ee 75 13 2 2 Low Voltage Directive Safety e o 75 Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 St r Baffle Fill Levels s cessc capac eR ee a fane dan sra 14 Tipping Prevention Bracket Installation 18 Front Control Pane
43. HA t err 1 ALPHA t Jerry yol ALPHA 1 ALPHA If RO and ALPHA were previously set for 100 000 and 0 0038500 respectively and the data for tp ty err and erry were as given above then the new values RO and ALPHA would be computed as 110 116 and 0 0038302 respectively Program the new values RO and ALPHA into the controller Check the calibra tion by setting the temperature to tj and ty and measuring the errors again If desired the calibration procedure may be repeated again to further improve the accuracy Calibration Example The bath is to be used between 25 C and 75 C and it is desired to calibrate the bath as accurately as possible for operation within this range The current val ues for RO and ALPHA are 100 000 and 0 0038500 respectively The calibra tion points are chosen to be 30 00 and 80 00 C The measured bath temperatures are 29 843 and 79 914 C respectively Refer to Figure 8 for ap plying equations to the example data and computing the new probe constants 11 Calibration Procedure Calibration Example RO 100 000 ALPHA 0 0038500 tp 30 00 C measured t 29 843 C ty 80 00 C measured t 79 914 C Compute errors err 29 843 30 00 C 0 157 C erry 79 914 80 00 C 0 086 C Compute RO m cues x 30 0 0157 x 80 0 0 0 00385 1 100 000 100 077 80 0 30 0 Compute ALPHA ALPHA 1 0 00385 x 80 0 0 157 1 0 00385 x
44. MANUAL X5 SET UP 3 pr Display EXIT Program Men rogral enu Temperature Le ML SET SETI Number of Set points pas eave hi EXIT Reset Cutout Yl l Cutout Active SET l Adjust Set point je SET gt Select Set point tata a kn ela aay L A EXIT it EXIT Select Setpoint Y SET SECONDARY FUNCTIONS Soak Time SET e EXIT Adjust Setpoint L gt SET EXIT Y I Y T E A SET Program Function Mode Y EXIT Display Power gt lt EXIT Adjust Vernier T EXIT T SET Y SET Y SET EXIT H Program Control Y f i Set PI tional Band la EXIT Sean onoi EXA e pls ani SET SET Y kf EXIT Scan Rate la EXm Set Cutout Temp I SET SET y Y EXIT Set Scale C F la EXITI C Configuration Menu AA SEJ SET A A A A A EXIT EXIT EXIT EXIT EXIT EXIT B Mi SET EXI T BG SET m x S J SET m x zi SET EXIT HGbt SET C EXT Adj bt 7 SET EXIT j 4 9 Controller Operation Temperature Set point 9 3 9 3 1 rESEE P Cutout reset function Press SET once more to reset the cutout SET Reset cutout This action switches the display to the set temperature function To return to displaying the temperature display press the EXIT button If the cutout is still in the over temperature fault condition the display continues to flash cutout The bath
45. O NOT over fill The Model 7381 Bath is not provided with a fluid Various fluids are available from Hart Scientific and other sources Depending on the desired temperature range any of the following fluids as well as others may be used in the bath e Water e Ethylene glycol water e Mineral oil e Silicone oil e Ethanol Fluids are discussed in detail in Section 8 1 Heat Transfer Fluid Remove any access hole cover from the bath and check the tank for foreign matter dirt remnant packing material etc Fill the bath with clean unpolluted fluid Fill the bath carefully through the large rectangular access hole to a level that will allow for stirring and thermal expansion Section 8 1 5 Thermal Expansion explains fluid expansion CAUTION DO NOT turn on the bath without fluid in the tank and the heating coils fully immersed See Section 7 4 1 Fluid Expansion Reser voir on how to use the fluid expansion reservoir 19 7381 Calibration Bath User s Guide 20 5 6 Be sure the fluid expansion reservoir is properly installed checking to insure it is clean and free of foreign matter Carefully monitor the bath fluid level as the bath temperature rises to prevent excessive overflow or splashing Remove ex cess hot fluid if necessary with caution Power With the bath power switch off plug the bath into an AC mains outlet of the appropriate voltage frequency and current capacity Refer to Section 3 1 Specifications f
46. ail in Sec tion 11 Calibration Procedure The probe parameters are accessed by pressing SET after the name of the pa rameter is displayed The value of the parameter may be changed using the UP and DOWN buttons After the desired value is reached press SET to set the parameter to the new value Press EXIT to skip the parameter ignoring any changes that have been made RO This probe parameter refers to the resistance of the control probe at 0 C Normally this is set for 100 000 ohms ALPHA This probe parameter refers to the average sensitivity of the probe between 0 and 100 C Normally this is set for 0 00385 C 49 7381 Calibration Bath User s Guide 50 9 13 9 13 1 9 13 2 Operating Parameters The operating parameters menu is accessed by pressing UP when the probe menu is displayed The operating parameters menu is indicated by PAr Operating parameters menu Press UP to enter the menu The operating parameters menu contains the cut out reset mode parameter cooling mode and hot gas bypass mode Cutout Reset Mode The cutout reset mode determines whether the cutout resets automatically when the bath temperature drops to a safe value or must be manually reset by the operator The parameter is indicated by Ckor 5E Cutout reset mode parameter Press SET to access the parameter setting The cutout is set at the factory for manual mode pend a
47. al codes and ordinances Consult a qualified electrician DO NOT use an extension cord or adapter plug e DO use a ground fault interrupt device This instrument contains a fluid A ground fault device is advised in case fluid is present in the electrical system and could cause an electrical shock 7381 Calibration Bath User s Guide Always replace the power cord with an approved cord of the correct rat ing and type If you have questions contact a Hart Scientific Authorized Service Center see Section 1 3 High voltage is used in the operation of this equipment Severe injury or death may result if personnel fail to observe the safety precautions Before working inside the equipment turn off the power and disconnect the power cord BATH FLUIDS 1 2 2 Fluids used in this bath may produce noxious or toxic fumes under certain circumstances Consult the fluid manufacturer s MSDS Material Safety Data Sheet Proper ventilation and safety precautions must be observed The instrument is equipped with a soft cutout user settable firmware and a hard cutout set at the factory Check the flash point boiling point or other fluid characteristic applicable to the circumstances of the bath oper ation Ensure that the soft cutout is adjusted to the fluid characteristics of the application As a guideline the soft cutout should be set 10 C to 15 C below the flash point of the bath fluid See Section 8 1 Heat Transfer Fluid for spec
48. alibrate the bath to improve the tem perature set point accuracy Calibration is done by adjusting the controller probe calibration constants RO and ALPHA so that the temperature of the bath as measured with a standard thermometer agrees more closely with the bath set point The thermometer used must be able to measure the bath fluid temper ature with higher accuracy than the desired accuracy of the bath By using a good thermometer and carefully following procedure the bath can be calibrated to an accuracy of better than 0 2 C over a range of 100 degrees Calibration Points In calibrating the bath RO and ALPHA are adjusted to minimize the set point error at each of two different bath temperatures Any two reasonably separated bath temperatures may be used for the calibration however best results will be obtained when using bath temperatures which are just within the most useful operating range of the bath The further apart the calibration temperatures the greater the calibrated temperature range and the calibration error If for in stance 0 C and 100 C are chosen as the calibration temperatures the bath may achieve an accuracy of 0 3 C over the range 10 to 110 C Choosing 30 C and 70 C may allow the bath to have a better accuracy of 0 1 C over the range 25 to 75 C but outside that range the accuracy may be only 0 5 C Measuring the Set point Error The first step in the calibration procedure is to measure the temperature erro
49. asket In order to do this remove the four screws on the top surface and the two screws at the rear of the bath Lift the cover just far enough to wipe out the collected oil e Heat transfer medium lifetime is dependent upon the type of medium and the conditions of use The fluid should be checked at least every month for the first year and regularly thereafter This fluid check provides a baseline for knowledge of bath operation with clean usable fluid Once some fluids have become compromised the break down can occur rap idly Particular attention should be paid to the viscosity of the fluid A sig nificant change in the viscosity can indicate that the fluid is contaminated being used outside of its temperature limits contains ice particles or is close to a chemical breakdown Once data has been gathered a specific maintenance schedule can be outlined for the instrument Refer to Section 8 General Operation for more information about the different types of fluids used in calibration baths e Depending on the cleanliness of the environment a schedule should be set for cleaning the condensing coil fins which can be accessed via the Re frigeration Condenser Access Door refer to Section 7 2 The schedule should be set dependent upon the laboratory environment to ensure that dust does not build up on the fins hampering the efficiency of the bath i e month bi monthly Use a vacuum or cloth to clean the fins 69 7381 Calibration Bath
50. bath for calibration start by e Placing the reference probe in the bath working area e Placing the probe to be calibrated the UUT in the bath working area as close as feasibly possible to the reference probe but not touching the bath tank surface areas Calibration of Multiple Probes Fully loading the bath with probes increases the time required for the tempera ture to stabilize after inserting the probes Using the reference probe as the guide ensures that the temperature has stabilized before starting the calibration 7 Parts and Controls Front Control Panel 7 1 Parts and Controls Front Control Panel The following controls and indicators are present on the controller front panel see Figure 3 below 1 the digital LED display 2 the control buttons 3 the bath on off power switch 4 the control indicator light and 5 the cooling on off switch Figure 3 Front Control Panel 1 The digital display is an important part of the temperature controller It dis plays the set point temperature and bath temperature as well as the various other bath functions settings and constants The display shows temperatures according to the selected scale units C or F 2 The control buttons SET DOWN UP and EXIT are used to set the bath temperature set point access and set other operating parameters and access and set bath calibration parameters A brief description of the functions of the buttons follows SET
51. ction 3 1 Specifications for power details Refer to and read the Cautions in Section 1 2 2 concerning brownout and over voltage protection Check the back panel label for the correct voltage and frequency prior to energizing the bath Turn the bath on using the front panel POWER switch The bath will turn on and begin to heat or cool to reach the previously programmed temperature set point The front panel LED display will indicate the actual bath temperature Set the cooling switch to ON for below or near ambient temperatures Note The actual temperature where cooling is required depends on the bath fluid and whether a cover is used over the access well Setting the Temperature In the following discussion and throughout this manual a solid box around the word SET UP DOWN or EXIT indicates the panel button to press while the dotted box indicates the display reading on the front panel Explanation of the button function or display reading is written at the right To view or set the bath temperature set point proceed as follows The front panel LED display normally shows the actual bath temperature 24 68 Bath temperature display ri When SET is pressed the display shows the set point memory that is cur rently being used and its value Eight set point memories are available SET Access set point selection l 25 0 Set point 1 25 0 C currently used Rue RYEN SAD DOE RON Dan ka Sete KAFE AY Press SET
52. cutout set point press UP or DOWN Decrement display CO TSL j New cutout set point 9 Controller Operation Controller Configuration 9 11 9 12 9 12 1 9 12 2 To accept the new cutout set point press SET SET Accept cutout set point The next function is the configuration menu Press EXIT to resume display ing the bath temperature Controller Configuration The controller has a number of configuration and operating options and calibra tion parameters which are programmable via the front panel These are ac cessed from the secondary menu after the cutout set point function by pressing SET There are 5 sets of configuration parameters probe parameters operat ing parameters serial interface parameters IEEE 488 interface parameters if installed and controller calibration parameters The menus are selected using the UP and DOWN keys and then pressing SET Pressing EXIT in any secondary menu exits and returns to displaying the temperature see Figure 5 on page 38 Controller Operation Flowchart Probe Parameters The probe menu is indicated by PrObE Probe parameters menu Press SET to enter the menu The probe parameters menu contains the pa rameters RO and ALPHA which characterize the resistance temperature rela tionship of the platinum control probe These parameters may be adjusted to improve the accuracy of the bath This procedure is explained in det
53. date the in struments to be calibrated or immersed in the bath Spare covers are avail able from Hart Scientific e A stainless steel baffle inside the tank insures proper fluid flow It also protects probes and thermometers from coming in contact with the stir rers There are slots near the bottom of the baffle for insertion of the liq uid in glass adaptor 7 Parts and Controls Back Panel 7 4 7 4 1 Back Panel On the back of the bath are the system fuses power cord high low voltage in dicator drain serial port IEEE 488 port if installed and the fluid expansion reservoir Fluid Expansion Reservoir The fluid expansion reservoir is attached to the rear panel of the bath Its pur pose is to receive excess fluid expanded in the process of heating the bath to higher temperatures Any liquid will expand when heated To prevent the bath from overflowing when the fluid expands the excess fluid must be removed ei ther prior to heating or by allowing it to drain out of the bath tank Note the fluid level must never be below the heating elements This bath has an overflow tube attached to the bath tank that extends to the rear of the bath and drains into the fluid expansion reservoir The reservoir has enough capacity to cover a large range of thermal expansion rates for different fluids No attempt must be made to plug the overflow tube to prevent fluid from draining Do not attempt to fill the bath to a level higher than
54. ding flash points toxicity and such issues must be considered You are responsible for reading the manufacturer s specifications and MSDS material safety data sheets and acting accordingly About the Chart The fluid chart visually illustrates some of the important qualities of the fluids shown 31 7381 Calibration Bath User s Guide Table 2 Table of Various Bath Fluids and Their Properties Fluid Lower Upper Thermal Thermal Hart Part Temperature Temperature Flash Viscosity Specific Specific Heat Conductivity Expansion Resistivity No Limit Limit Point centistokes Gravity cal g C cals cm C cm cm C 10 0 cm Halocarbon 0 8 100 C v 70 C e NONE 5 7 50 C 1 71 40 C 0 2 0 0004 0 0011 5019 0 8 40 C 0 5 70 C Ethanol 97 C fr 16 C fl cc 16 C 109 20C 0 809 20 C 0 61 0 00047 Methanol 96 C fr 10 C fl cc 12 C 130 350 0 810 0 C 0 6 0 0005 20 C 0 0014 25 C 0 66 0 C 0 792 20 C 0 45 20 C Water 0 C fr 95 C b NONE 1 25 C 1 00 1 00 0 0014 0 0002 25 C 0 4 75 C Ethylene 30 C fr 90 C b NONE 7 0 C 1 05 0 8 Q 0 C 0 001 Glycol 50 5020 2 50 C 0 7 100 C Mineral Oil No 7 10 C v 166 C fl 168 C 15 75 C 0 87 25 C 0 48 25 C 0 00025 25 C 0 0007 50 C 5 25 C 5011 5 125 C 0 84 75 C 0 53 75 C 0 81 0 125 C 0 57 125 C Silicone Oil Type 40
55. doors ee EER OS va aS 51 9 14 Serial Interface Parameters 52 9 14 1 Baud Rats e 6 oe adem oe ee Pewee a 53 9 14 2 Sample Periodes 2e oats ne eas be ww BS dex vk C x pde s 53 9 14 3 Duplex Mode ass Rawls 4 Soe ai Gi a BY we Re Sie BSE 53 9 14 4 Eineteeds uS Seres dv Mere de pad ritis pim a y ud dic ve Rte Ge te atta id 54 9 15 IEEE 488 Parameters 54 9 15 1 IBBE 488 Address 4 4 s oom y dik d e DORMS ROS 54 9 15 2 Transmission Termination ees 55 916 Calibration Parameters 55 9 16 1 CTO ect apewa nea W A do ee eh A RS 56 9 16 2 BO atid BG zi ud amp ak kouwi a ee ed a tie di aia sa Halo ee eed os 56 9 16 3 Hand Lo isis were Oe GR Rly BG ee Ge Ao Sy Sos Geb de d eh Be ae 56 9 16 4 A pot a focii oes ad Dose M ee ee le icd deeds we adh Tech fen 56 10 Digital Communication Interface 57 10 1 Serial Communications 57 10 1 1 ITIN MCCC Ga doa e A e ed f Ma e ai ee Rel ee a eed dada 58 10 1 2 SOW Pes e v a Bal ae als Eger 2G REO a X Goal ae ae t 58 10 L2 1 Baud Rate ss 3 oue oec ee em Rue nui xe o c Y 3S3 A Bw See SC 58 10 1 2 2 Sample Periods oe S eX eor HANC re me RS 58 10 1 2 3 Duplex Mode u s x ooo eR di p di qe OE Re BO ob EUR US dude 59 101 24 Lined s eee eh ce Gog Shae aol Baas ed e e Rc de 59 10 1 3 Seral Operation ss boa ehe do ete dede dedi Ae had oe de e depended 59 10
56. e sample period The current sample period value will be displayed SA Current sample period seconds ENA FETE DEDE ER EKRAN KE A LOA ET Adjust the value with UP or DOWN and then use SET to set the sample rate to the displayed value 5A 60 New sample period prd Duplex Mode The next parameter is the duplex mode The duplex mode may be set to full du plex or half duplex With full duplex any commands received by the bath via the serial interface are executed and immediately echoed or transmitted back to 53 7381 Calibration Bath User s Guide 54 9 14 4 9 15 9 15 1 the device of origin With half duplex the commands are executed but not ech oed The duplex mode parameter is indicated by A Al Linefeed The final parameter in the serial interface menu is the linefeed mode This pa rameter enables on or disables off transmission of a linefeed character LF ASCII 10 after transmission of any carriage return The linefeed parameter is indicated by A TO A oO O OTE IEEE 488 Parameters Baths may optionally be fitted with an IEEE 488 GPIB interface In this case the user may set the interface address and the transmission termination charac ter within the IEEE 488 parameter menu This menu does not appear on baths not fitted with the interface The menu is accessed by pressing UP from the serial parameter menu The menu is indicated by IEEE IEEE 488 parame
57. e the automatic functioning therefore these selections are made avail able either through the front panel or through the digital communications interface 61 7381 Calibration Bath User s Guide Table 5 Interface Command Summary Command Command Returned Command Description Format Example Returned Example Acceptable Values Display Temperature Read current set point s etpoint S set 9999 99 C set 150 00 C or F Set current set point to n s etpoint n s 150 Instrument Range t emperature n t 150 40 to 150 C Read vernier v ernier V v 9 99999 v 0 00000 Set vernier to n v ernier n v 00018 Depends on Configuration Read scan function sc an SC scan ON or scan ON OFF Set scan function sc an on of f ON or OFF Turn scan function on sc an on se on Turn scan function off sc an of f sc of Read scan rate sr ate Sr srat 9 999 C or srat 0 010 F min C min Set scan rate to n degrees per sr ate n sr 5 0 001 to 5 000 C min minute 0 001 to 9 000 F min Read temperature t emperature t t 9999 99 C or t 55 69 C F Read temperature units u nits u Ux u C Set temperature units u nits c f CorF Set temperature units to u nits c u C Celsius Set temperature units to u nits f u f Fahrenheit Ramp and Soak Menu Read number of programmable pn pn pn 9 pn 2 set points Set number of programmable pn n pn 4 2to8 set points to n R
58. ead programmable set point psn ps3 psn 9999 99 C pst 50 00 C number n or F Set programmable set point num psn n ps3 50 1 to 8 Instrument Range ber nto n 40 to 150 C Read program set point soak time pt pt ti 999 ti 5 Set program set point soak time pt n pt 5 0 to 500 to n minutes Read program control mode pc pc prog OFF or prog OFF ON Set program control mode pc g o s top c ont GO or STOP or CONT Start program pc g o pc g Stop program pc s top pc s Continue program pc c ont pcc Read program function pf pf pf 9 pf 3 62 10 Digital Communication Interface Cooling Control Interface Command Summary Continued Command Command Returned Command Description Format Example Returned Example Acceptable Values Set program function to n pf n pf 2 1to4 Secondary Menu Read proportional band setting pr op band pr pr 9 999 pr 0 315 Set proportional band to n pr op band n pr 0 326 Depends on Configuration Read cutout setting c utout C cu 999 x xxx cu 120 C in Set cutout setting c utout n r eset Set cutout to n degrees c utout n c 120 Temperature Range Reset cutout now c utout r eset c r Read heater power po wer po po 9999 po 1 duty cycle Configuration Menu Probe Menu Read RO calibration parameter r 0 r r0 999 999 r0 100 578 Set RO calibration parameter to n r 0 n r 100 324 98 0 to 104 999
59. ection carefully and attempt to understand and solve the problem If the probe seems faulty or the problem cannot otherwise be solved contact an Authorized Service Center see Section 1 3 on page 5 for assistance Be sure to have the instrument model number serial number voltage and problem de scription available Problem Causes and Solutions The heater indicator LED stays The display does not show ut out nor displays an incorrect bath red but the temperature does not temperature and the controller otherwise appears to operate nor increase mally The problem may be insufficient heating no heating at all or too much cooling One or more burned out heaters or blown heater fuses may also cause this problem If the heaters seem to be burned out contact an Authorized Service Center see Section 1 3 on page 5 for assis tance The controller display flashes The display flashs uvt o ut alternately with the process Cut out and the heater does temperature not operate e Ifthe process temperature displayed seems grossly in error consult the following problem The display flashes ut out and an in correct process temperature Normally the cutout disconnects power to the heater when the bath temperature exceeds the cutout set point causing the temperature to drop back down to a safe value If the cutout mode is set to AUTO the heater switches back on when the temperature drops
60. ector and the suggested cable ten ur wiring To eliminate noise the DB 9 Pin DB 9 Pin serial cable should be shielded 1NC ot DCD with low resistance between the e MIDS pes 3TxD 3TxD connector DB 9 and the ANC re 4DTR shield 5 GND 5GND 6NC 6 DSR 7RTS 7 RTS 10 1 2 Setup acts 8CTS 9NC 9NC Before operation the serial in terface of the bath must first be set up by programming the baud Instrument Computer DTE rate and other configuration pa Connector Connector rameters These parameters are 2B SFin DEN programmed within the serial ed SIND interface menu 3TxD 3RxD 4NC 4RTS To enter the serial parameter 5 GNDe 5CTS programming menu press BNC f e 6DSR EXIT while holding down pall l SET then release both 9NC le 20DTR buttons to enter the secondary Figure 7 Serial Communications Cable Wiring menu Press SET repeatedly until the display reads Pr obE This is the menu selection Press UP repeatedly until the serial in terface menu is indicated with SEr AL Finally press SET to enter the se rial parameter menu In the serial interface parameters menu are the baud rate the sample rate the duplex mode and the linefeed parameter 10 1 2 1 Baud Rate The baud rate is the first parameter in the menu The display prompts with the baud rate parameter by showing BA U d Press SET to choose to set the baud rate The current baud rate value is displa
61. ed The default setting is full duplex The mode may be changed using UP or DOWN Press SET to save the new setting or EXIT to abort and skip to the next parameter Linefeed The final parameter in the serial interface menu is the linefeed mode This pa rameter enables 8 n or disables 8 F F transmission of a linefeed charac ter LE ASCII 10 after transmission of any carriage return The default setting is with linefeed on The mode may be changed using UP or DOWN Press SET to set the sample period to the new value or EXIT to abort and skip to the next parameter Serial Operation Once the cable has been attached and the interface set up properly the control ler will immediately begin transmitting temperature readings at the pro grammed rate The set point and other commands may be sent to the bath via the serial interface to set the bath and view or program the various parameters The interface commands are discussed in Section 10 3 Interface Commands IEEE 488 Communication optional The IEEE 488 interface is available as an option Baths supplied with this op tion may be connected to a GPIB type communication bus which allows many instruments to be connected and controlled simultaneously To eliminate noise the GPIB cable should be shielded Setup To use the IEEE 488 interface connect an IEEE 488 standard cable to the back of the bath set the device address and set the transm
62. em should be used As with most oils mineral oil expands as temperature increases Be careful not to fill the bath too full to avoid overflows when heated see Section 7 4 1 Fluid Expansion Reservoir The viscosity and thermal characteristics of mineral oil is poorer than water so temperature stability will not be as good Mineral oil has very low electrical conductivity Use caution with mineral oil since it is flammable and may also cause serious injury if inhaled or ingested 8 General Operation Heat Transfer Fluid 8 1 10 4 8 1 11 8 1 11 1 8 1 11 2 A Silicone Oil Silicone oils are available which offer a much wider operating temperature range than mineral oil Like most oils silicone oils have temperature control characteristics which are somewhat poorer than water The viscosity changes significantly with temperature and thermal expansion also occurs These oils have very high electrical resistivity Silicone oils are fairly safe and non toxic but can be expensive Silicone oils can degrade and eventually breakdown when used at higher portions of their temperature range for long periods of time This limits their usable lifetime depending on the duration spent at high temperature Fluid Characteristics Charts CAUTION Due to the unique properties of silicone oils and their ability to migrate and creep through seals adequate ventilation must be used to prevent oil vapors from creating an oily dirty environment Oily
63. es maximum cooling capacity in a range where the hot gas bypass would normally be on e The application requires maximum cooling capacity when the hot gas by pass would normally be on e When using the bath at temperatures below 31 C in an ambient of less than 23 C a small benefit to stability may be realized by using the hot gas bypass e The refrigeration may be beneficially used for short times less than one hour above 60 C but less than 100 C This list is not intended to be complete but only suggests some of the situa tions when automatic modes may not be best Most of the time the automatic functions are adequate and should be used 9 Controller Operation Bath Temperature 9 1 9 2 Controller Operation This chapter discusses in detail how to operate the bath temperature controller using the front control panel Using the front panel key switches and LED dis play the user may monitor the bath temperature set the temperature set point in degrees C or F monitor the heater output power adjust the controller propor tional band set the cutout set point and program the probe calibration parame ters operating parameters serial and IEEE 488 interface configuration and controller calibration parameters Operation is summarized in Figure 5 on page 38 Bath Temperature The digital LED display on the front panel allows direct viewing of the actual bath temperature This temperature value is what is normally s
64. es are an improper proportional band setting or the fluid being used e Ifthe bath temperature does not achieve the expected degree of sta bility when measured using a thermometer try adjusting the propor tional band to a narrower width as discussed in Section 9 9 Proportional Band e Check to ensure the fluid has not deteriorated or is not too thick The controller alternately heats for a while then cools The bath is not stable and the duty cycle is not constant The proportional band being too narrow typically causes this oscilla tion Increase the width of the proportional band until the temperature stabilizes as discussed in Section 9 9 Proportional Band 73 7381 Calibration Bath User s Guide 13 2 13 2 1 13 2 1 1 74 Problem Causes and Solutions The controller erratically heats If both the bath temperature and output power do not vary periodically then cools control is unstable but in a very erratic manner the problem may be excess noise in the system Noise due to the control sensor should be less than 0 001 C However if the probe has been damaged or has developed an inter mittent short erratic behavior may exist The probe is located inside the stirrer motor cover Check for a damaged probe or poor connection between the probe and bath e Check the resistance between the probe pins and the sheath They should be open Intermittent shorts in the heater or controller electronic ci
65. et Cutout iuo eed BERG s n a Roue eo a E E 37 Temperature Setpoint less 39 9 3 1 Programmable Set pointS o e 39 9 3 2 Setpoint Valle v a foci da he le Vine 40 9 3 3 Setpoint Vernier goes v ce ek L ID ROS So A eh ers 40 SCAN 4 uu med BLUES Pus EGOS SEE GE dd ess 41 9 4 1 Scan Control coso 4 3 ede de o Eee om deel e a v deus 41 9 4 2 Scan Rates v ow eb ee a o ee ew woe wR Red 41 Temperature Scale Units cse 42 Ramp and Soak Program 2 2 2 o 42 9 6 1 Number of Program Set points 2 sa corso oresoao ssaa 43 9 6 2 SEPO sns aa BG aa A ao a la am fiy doas 43 9 6 3 Program Soak Time s s sie asco tal A daa Be elke aye tala oy ge aw 43 9 6 4 Program Function Mode oeo e o o e 44 9 6 5 Program Control sucra a ac Baw Bake o dete 44 9 7 secondary Men o srt ou ea ei cR BS EGS 45 9 8 Heater POWT cuca opem neum edem Berek ye tet 45 9 9 Proportional Band llle 45 9 I0 Qutout dara eek be OS SPER ec ew eee eR bees 48 9 1 Controller Configuration les 49 9 12 Probe Parameters taner derri pana 49 9 12 1 ROS d adus f Bok ak e ba eee ee Mba di qi 49 9 12 2 AEPHA 252a cates eoe qnd alo xcd apr ent p p NOUS ado ees 49 9 13 Operating Parameters 50 9 13 1 Cutout Res t Mode wiki aeiy ap esp ide a a a RR ER 50 9 13 2 Cooling Modes us rin dew 4 dew de ap de od pi AG f ak Mi op oem e 50 9 13 3 Hot Gas Bypass Mode sos
66. f the fluid to consider is the flash point The flash point is the temperature at which there is sufficient vapor given off so that when there is adequate oxygen present and an ignition source is applied the va por will ignite This does not necessarily mean that fire will be sustained at the flash point The flash point may be either of the open cup or closed cup type Either condition may occur in a bath situation The open cup flash point is mea sured under the condition of vapors escaping the tank The closed cup flash point is measured with the vapors being contained within the tank Since oxy gen and an ignition source is less available inside the tank the closed cup flash point will be lower than the open cup flash point Environmentally hazardous fluids require special disposal according to applica ble federal or local laws after use 29 7381 Calibration Bath User s Guide 30 8 1 9 8 1 10 8 1 10 1 8 1 10 2 8 1 10 3 Cost Cost of bath fluids may vary greatly from cents per gallon for water to hun dreds of dollars per gallon for synthetic oils Cost may be an important consid eration when choosing a fluid Commonly Used Fluids Below is a description of some of the more commonly used fluids and their characteristics Water Water is often used because of its very low cost its availability and its excel lent temperature control characteristics Water has very low viscosity and good thermal conductivity
67. f vaporization Decomposition The temperature may reach a point at which decomposition of the fluid begins Further increasing the temperature may accelerate decomposi tion to the point of danger or impracticality Silicone oils can oxidize causing the fluid to thicken Replace at the first sign of increasing viscosity Stirring Stirring the bath fluid is very important for stable temperature control The fluid must be mixed well for good temperature uniformity and fast controller response The stirrer is precisely adjusted for optimum performance Power Power to the bath is provided by an AC mains supply Refer to Section 3 1 Specifications for power details Refer to and read the CAUTION at the front of the manual concerning brownout and over voltage protection Check the back panel label for the correct voltage and frequency prior to energizing the bath Power to the bath passes through a filter to prevent switching spikes from being transmitted to other equipment To turn on the bath press the control panel power switch to the ON position The stirring motor will turn on the LED display will begin to show the bath temperature and the heater will turn on or off until the bath temperature reaches the programmed set point When powered on the control panel display will briefly show a four digit num ber This number indicates the number of times power has been applied to the bath Also briefly displayed is data which indicates the
68. g Press SET to activate the new program control command and return to the temperature display SET Activate new command Secondary Menu Functions which are used less often are accessed within the secondary menu The secondary menu is accessed by pressing SET and EXIT simulta neously and then releasing The first function in the secondary menu is the heater power display Heater Power The temperature controller controls the temperature of the bath by pulsing the heater on and off The total power being applied to the heater is determined by the duty cycle or the ratio of heater on time to the pulse cycle time This value may be estimated by watching the red green control indicator light or read di rectly from the digital display By knowing the amount of heating the user can tell if the bath is heating up to the set point cooling down or controlling at a constant temperature Monitoring the percent heater power lets the user know the stability of the bath temperature With good control stability the percent heating power should not fluctuate more than 1 within one minute The heater power display is accessed in the secondary menu Press SET and EXIT simultaneously and release The heater power is displayed as a percent age of full Bi E e Access heater power in secondary menu le Pct 2 Heater power in percent pee To exit out of the secondary menu press EXIT To continue on to the propor
69. gy consumption for specific bath conditions There are three HGb modes Auto On manual or Off Normally the HGb is set to the Auto mode If for some special application the automatic mode is undesir able the HGb can be set to On or Off Automatic Mode This mode is best for most applications When scanning down in temperature for set points greater than 2 C below the current tempera ture the system switches to maximum cooling capacity It will automatically switch back to HGb mode just before the new set point is reached but only if the new set point is above 31 C For temperatures below 31 C the capacity will remain in the maximum cooling condition Maximum cooling is generally required at such low temperatures On Mode The On mode selects hot gas capacity control for all temperatures and conditions where the refrigeration is on The amount of the capacity con trol is manually controlled and can be selected in the next menu position The percent of power Po represents the amount of reduction selected Zero represents no reduction in cooling capacity while 100 represents the total available reduction capacity that will be applied An increase of the Po will decrease the cooling power and correspondingly reduce the percent of heater power applied to maintain the temperature Off Mode The Off Mode does not permit any capacity reduction and the cool ing is at maximum throughout the temperature range used by the refrigeration
70. h evaporation fl flash point fr freeze point v viscosity Flash point test oc open cup cc closed cup 32 Temperature Range The temperature scale is shown in degrees Celsius The shaded bands indicate the fluids general range of application Qualities includ ing pour point freeze point important viscosity points flash point boiling point and others may be shown Freezing Point The freezing point of a fluid is an obvious limitation to stir ring As the freezing point is approached high viscosity may also limit performance Pour Point This represents a handling limit for the fluid 8 General Operation Heat Transfer Fluid 100 C orc 100 C Silicone Oil 5017 Silicone Oil 5014 Silicone Oil 5013 Silicone Oil 5012 Silicone Oil 5010 HFE 7500 5023 Halocarbon 5019 Mineral Oil 5011 Water Methanol Ethanol Ethylene Glycol 50 50 with H20 5020 Dynalene HF LO 5022 Bath Salt 5001 200 C 300 C 400 C 500 C 600 C FL 302 C FL 280 C 10 cS FL 232 C ES FL 211 C 10 Cs FL 133 C viscosity while vaporization and decomposition increase Black area represents liquid range with excessive viscosity Legend Shaded area represents usable range of fluid starting at 50 centistokes Lighter shading represents dec
71. he constants The memory backup battery may be weak causing errors in data as described in the prob lem The display flashes cutout and an incorrect process tempera ture e Check that the control probe has not been struck bent or damaged If the cause of the problem remains unknown contact an Authorized Service Center see Section 1 3 on page 5 for assistance The controller does not maintain controller parameters or parame ters are reset each time the power to the unit is removed Note Before performing the memory check you need to record the controller calibration parameters found in the CAL menu of the instru ment and any user adjusted parameters that you have changed such as the programmable set points and proportional band Memory Check Doing a memory check is the easiest way to verify the ability of the battery to maintain controller parameters 1 Power off the instrument 2 Disconnect the instrument from AC power for 10 seconds 3 Reconnect the AC power and power on the instrument 4 If the display shows n T and or the cycle count shows a low num ber such as 0002 the battery is spent and should be replaced Con tact an Authorized Service Center for assistance 5 After replacing the battery you must reprogram the calibration and user adjustable parameters into the controller The controller shows that the out put power is steady but the pro cess temperature is unstable Possible caus
72. hes of clearance for air circulation See Figure 2 Screw the bracket securely to the floor Installation Of The Bath Slide the back casters of the bath completely into the tipping bracket Lock the front casters of the bath Check that the bath is securely locked into the tipping 5 Installation Dry out Period 5 4 5 5 bracket by gently pushing on the bath Proceed to fill the bath with the applica ble bath fluid after reading the entire User s Guide If you have any questions concerning installation of the tipping prevention bracket please contact a Hart Authorized Service Center Dry out Period If this equipment is used in a manner not specified by the manufacturer the protection provided by the equipment may be impaired Before initial use or after transport or after storage in humid or semi humid environments or anytime the bath has not been energized for more than 10 days the instrument needs to be energized for a dry out period of 2 hours be fore it can be assumed to meet all of the safety requirements of the IEC 1010 1 If the product is wet or has been in a wet environment take necessary measures to remove moisture prior to applying power such as storage in a low humidity temperature chamber operating at 50 C for 4 hour or more Bath Preparation and Filling CAUTION Avoid spilling fluid over the control panel Immediately clean up any spilling Cover the panel if necessary during filling D
73. hown on the dis play The units C or F of the temperature value are displayed at the right For example Bath temperature in degrees Celsius The temperature display function may be accessed from any other function by pressing the EXIT button Reset Cutout If the over temperature cutout has been triggered then the temperature display will alternately flash Cub out Indicates cutout condition The message continues to flash between the actual temperature and Cut out until the temperature is reduced and the cutout is reset The cutout has two modes automatic reset and manual reset The mode de termines how the cutout is reset which allows the bath to heat up again When in automatic mode the cutout will reset itself as soon as the temperature is low ered below the cutout set point With manual reset mode the cutout must be re set by the operator after the temperature falls below the set point When the cutout is active and the cutout mode is set to manual reset then the display will flash cutout until the user resets the cutout To access the re set cutout function press the SET button SET Access cutout reset function The display indicates the reset function 37 7381 Calibration Bath User s Guide
74. ific information on bath fluids and Section 9 10 Cutout A CAUTIONS Always operate this instrument at room temperature between 41 F and 122 F 5 C to 50 C Allow sufficient air circulation by leaving at least 6 inches 15 cm of clearance around the instrument When filling the tank ensure the immersion coils are completely covered DO NOT fill above the stir baffle see Figure 1 on page 14 DO NOT overfill the bath Overflowing fluid may damage the electrical system See Section 5 3 Bath Preparation and Filling for specific instruc tions Read Section 6 Bath Use before placing the bath into service DO NOT turn the bath on without fluid in the tank and the heating coils fully immersed See Section 7 4 1 Fluid Expansion Reservoir for more information on Fluid Expansion Reservoir use DO NOT change the values of the bath calibration constants from the fac tory set values The correct setting of these parameters is important to the safety and proper operation of the bath The refrigeration may be damaged or the lifetime shortened if the set point temperature is set above 60 C for more than one hour with the refrigeration manually on Ensure that the refrigeration is off when the bath is used above 60 C The Factory Reset Sequence should be performed only by authorized personnel if no other action is successful in correcting a malfunction You 1 Before You Start Authorized Service Centers 1 3 must have a copy
75. in the main menu is the scan rate The scan rate can be set from 0 001 to 5 0 C min The maximum scan rate however is actually limited by the natural heating or cooling rate of the instrument This is typically less than 1 C min especially when cooling The scan rate function appears in the main menu after the scan control function The scan rate units are in degrees per minute degrees C or F depending on the selected units 5r 0 010 Scan rate in C min 41 7381 Calibration Bath User s Guide 42 9 5 9 6 Press SET to accept the new scan rate and continue Temperature Scale Units The temperature scale units of the controller may be set by the user to degrees Celsius C or Fahrenheit F The units are used in displaying the bath tem perature set point vernier proportional band and cutout set point The temperature scale units selection is accessed after the vernier adjustment function by pressing SET From the temperature display function access the units selection by pressing SET 4 times Un C i Scale units currently selected ERE RO RE ROL LESON Press UP or DOWN to change the units Change units New units selected O Press SET to accept the new selection and resume displaying the bath temperature SET Set the new units and resume temperature display Ramp and Soak Program The ramp and soak program feature allows the user to program a number of
76. ing Prevention Bracket for Tipping Prevention Bracket installation instructions Fill the bath tank with an appropriate liquid Be sure to select the correct fluid for the temperature range of the calibration Bath fluids should be selected to operate safely with adequate thermal properties to meet the application require ments For operation at moderate bath temperatures clean distilled water works well Carefully pour the fluid into the bath tank through the large rectangular access hole above the tank avoiding spilling any fluid CAUTION When filling the tank ensure the immersion coils are com pletely covered DO NOT FILL ABOVE THE STIR BAFFLE See Figure 1 Maximum Fill Level Top of Baffle Minimum Fill Level Line Figure 1 Stir Baffle Fill Levels 4 Quick Start Power 4 3 4 4 An overflow drain is provided for excess bath fluid due to expansion This drains the fluid into the fluid expansion reservoir for reuse See Section 7 4 1 Fluid Expansion Reservoir for details in using the reservoir Note As the temperature of the bath increases the fluid level will increase see Section 6 Bath Use on page 21 and Section 8 1 5 Thermal Expansion on page 28 Power Plug the bath power cord into a mains outlet of the proper voltage frequency and current capability Refer to Se
77. ing it to maintain a more constant temperature For good control the viscosity should be less than 10 centistokes 50 centistokes is the practical upper limit of allowable viscosity Viscosity greater than this causes very poor control stabil ity because of poor stirring and may also overheat or damage the stirring motor Viscosity may vary greatly with temperature especially with oils When using fluids with higher viscosities the controller proportional band see Section 9 9 Proportional Band may need to be increased to compensate for the reduced response time Otherwise the temperature may begin to oscillate Specific Heat Specific heat is the measure of the heat storage ability of the fluid Specific heat to a small degree affects the control stability and the heating and cooling rates Generally a lower specific heat means quicker heating and cooling The 27 7381 Calibration Bath User s Guide 28 proportional band may require some adjustment depending on the specific heat of the fluid Thermal Conductivity Thermal conductivity measures how easily heat flows through the fluid Ther mal conductivity of the fluid affects the control stability temperature unifor mity and temperature settling time Fluids with higher conductivity distribute heat more quickly and evenly improving bath performance Thermal Expansion Thermal expansion describes how much the volume of the fluid changes with temperature Thermal expansion
78. ission termination character To enter the IEEE 488 parameter menu press EXIT while holding down SET then release both buttons to enter the secondary menu Press SET re peatedly until the display reaches Pr 85 E Press UP repeatedly until the 59 7381 Calibration Bath User s Guide IEEE 488 interface menu is indicated with EEE Press SET to enter the IEEE 488 parameter menu 10 2 1 1 IEEE 488 Address The IEEE 488 address is indicated with Addr E55 Press SET to program the address The default address is 22 Change the device address of the bath if necessary to match the address used by the communication equipment by pressing UP or DOWN Press SET to save the new setting or EXIT to abort and skip to the next parameter 10 2 1 2 Transmission Termination The IEEE 488 transmission termination is indicated with E 0 5 Press SET to access the termination character The present setting is displayed Press UP or DOWN to change the setting Press SET to save the new setting or EXIT to abort and skip to the next parameter 10 2 2 IEEE 488 Operation 60 10 3 Commands may now be sent via the IEEE 488 interface to read or set the tem perature or access other controller functions All commands are ASCII charac ter strings and are terminated with a carriage return CR ASCII 13 Interface commands are listed below Interface Commands
79. l 2 ee ee 23 Chart of Various Bath Fluids and Their Properties 33 Controller Operation Flowchart o o 38 Bath Temperature Fluctuation At Various Proportional Band Settings 46 Serial Communications Cable Wiring 58 Calibration Example cca cos aoe e aec ea a a e e 67 vi Tables Table 1 Table 2 Table 3 Table 4 Table 5 Table 5 Table 5 International Electrical Symbols s 1 Table of Various Bath Fluids and Their Properties 32 Program Mode Setting Actions o o 44 Typical Proportional Band Settings for Various Fluids 47 Interface Command Summary e o o e 62 Interface Command Summary Continued 63 Interface Command Summary Continued 64 1 Before You Start Symbols Used 1 1 Before You Start Symbols Used Table 1 lists the International Electrical Symbols Some or all of these symbols may be used on the instrument or in this manual Table 1 International Electrical Symbols Symbol Description ANG AC Alternating Current AZ AC DC Battery Complies with European Union directives N MA DC Double Insulated Electric Shock Fuse PE Ground Hot Surface Burn Hazard Read the User s Manual Important Information Off On OPPOUPH 7381 Calibration Bath User s Guide Symbol Description G Canadian Standards Associati
80. l system when the cooling power switch on the front panel is activated Under normal conditions the refrigeration is on at any temperature below approximately 60 C see Sec tion 8 6 Refrigeration When the bath is controlling at temperatures between 31 C and 60 C the refrigeration is in the hot gas bypass or reduced cooling mode Below 31 C the refrigeration is in the high cooling mode and the hot gas bypass is turned off automatically When the bath is cooling from one tem perature to another below 60 C cooling is at maximum until the bath is within 0 5 C of the set point These conditions are the default conditions but may be altered in the following ways e The cooling refrigeration may be set to operate in the auto on or off modes See Section 9 13 2 Cooling Mode e The hot gas bypass or reduced cooling mode may also be set to on man ual off or auto The auto modes allow the bath to operate automatically in the manner de scribed above The cooling on function eliminates this auto feature and the refrigeration is on at all times unless the front panel switch is turned off or until some other menu selection is made The hot gas bypass mode selection works the same way The auto function is the default and active until off or on is se lected On means it is always on with manual selection and off is always off or cooling always on maximum It may desirable for different reasons to eliminat
81. mory does not remedy the problem there may be a failed electronic component Contact an Authorized Service Center see Section 1 3 on page 5 for assistance The controller may need to be reset Perform the following Factory Reset Sequence Factory Reset Sequence Hold the SET and EXIT buttons down at the same time while powering up the instrument The instrument dis play shows 1 n t the model number and the firmware version Each of the controller parameters and calibration constants must be reprogrammed The values can be found on the Report of Test that was shipped with the instrument The displayed process tempera ture is in error and the controller remains in the cooling or the heating state at any set point value Possible causes may be either a faulty control probe or erroneous data in memory The probe may be disconnected burned out or shorted The probe is located inside the stirrer motor cover Check that the probe is connected properly The probe may be checked with an ohmmeter to see if it is open or shorted The probe is a platinum 4 wire Din 43760 type The resistance should read 0 2 to 2 0 ohms between pins 1 and 2 on the probe connector and 0 2 to 2 0 ohms between pins 3 and 4 It should read 100 to 300 ohms be tween pins 1 and 4 depending on the temperature If the probe ap pears to be defective contact an Authorized Service Center see Section 1 3 on page 5 for assistance If the problem is not the
82. nd the condenser fins should be kept clean Bath Tank and Lid The bath tank and lid assembly includes the tank the control probe the stir ring motor the access hole and the access hole cover The stirring motor cover covers the stirring motor cooling fan and control probe e The bath tank is constructed of stainless steel It is very resistant to oxida tion in the presence of most chemicals and over a wide range of tempera tures e The control probe provides the temperature feedback signal to the con troller allowing the controller to maintain a constant temperature The control probe is a precision platinum resistance thermometer PRT It is delicate and must be handled carefully The control probe is placed in the small hole in the top of the bath so that the probe tip is fully immersed in the bath fluid e The stirring motor is mounted on the bath tank lid It drives the stirring propeller to provide mixing of the bath fluid Proper mixing of the fluid is important for good constant temperature stability e On the bath lid is a large access hole This is used for filling the bath with fluids and placement of thermometers and devices into the bath e An access hole cover should be used to cover the access opening in the top of the bath at all times This improves bath temperature stability pre vents excess fluid evaporation or fumes and increases safety with hot fluid The user may drill or cut holes in the cover to accommo
83. on us OVERVOLTAGE Installation CATEGORY II Pollution Degree 2 per IEC1010 1 re CAT IL fers to the level of Impulse Withstand Voltage protection provided Equipment of OVERVOLTAGE CATEGORY II is energy consuming equipment to be supplied from the fixed installation Examples include household office and laboratory appliances The European Waste Electrical and Electronic Equipment WEEE Directive 2002 96 EC mark C TIC Australian EMC mark 1 2 Safety Information Use this instrument only as specified in this manual Otherwise the protection provided by the instrument may be impaired Refer to the safety information in Warnings and Cautions sections The following definitions apply to the terms Warning and Caution WARNING identifies conditions and actions that may pose hazards to the user CAUTION identifies conditions and actions that may damage the in strument being used 1 2 1 A WARNINGS To avoid possible electrical shock or personal injury follow these guidelines GENERAL DO NOT use the instrument for any application other than calibration work The instrument was designed for temperature calibration Any other use of the instrument may cause unknown hazards to the user DO NOT use the instrument in environments other than those listed in the user s guide DO NOT overfill the bath Overflowing extremely cold or hot fluid may be harmful to the operator See Section 5 5 Ba
84. or power details Refer to and read the CAUTION at the front of the manual concerning brownout and over voltage protection Check the back panel label for the correct voltage and frequency prior to energizing the bath 6 Bath Use General 6 6 1 6 2 Bath Use A CAUTION Read this section entitled BATH USE before placing the bath in service The information in this section is for general information only It is not de signed to be the basis for calibration laboratory procedures Each laboratory needs to write their specific procedures General Be sure to select the correct fluid for the temperature range of the calibration Bath fluids should be selected to operate safely with adequate thermal proper ties to meet the application requirements Also be aware that fluids expand when heated and could overflow the bath if not watched Refer to General Op eration Section 8 for information specific to fluid selection and to the MSDS sheet specific to the fluid selected Generally baths are set to one temperature and used to calibrate probes only at that single temperature This means that the type of bath fluid does not have to change Additionally the bath can be left en ergized reducing the stress on the system The bath generates extreme temperatures Precautions must be taken to prevent personal injury or damage to objects Probes may be extremely hot or cold when removed from the bath Cautiously handle probes to prevent
85. ows different types of probes to be calibrated at the same time However stem effect from different types of probes is not to tally eliminated Even though all baths have horizontal and vertical gradients these gradients are minimized inside the bath work area Nevertheless probes should be inserted to the same depth in the bath liquid Be sure that all probes are inserted deep enough to prevent stem effect From research at Hart Scien tific we suggest a general rule of thumb for immersion depth to reduce the stem effect to a minimum 20 x the diameter of the UUT the sensor length Do not submerge the probe handles If the probe handles get too warm during calibration at high temperatures a heat shield could be used just below the probe handle This heat shield could be as simple as aluminum foil placed around the handle or as complicated as a specially designed reflective metal apparatus When calibrating over a wide temperature range starting at the highest temper ature and progressing down to the lowest temperature can generally achieve better results Probes can be held in place in the bath by using probe clamps or drilling holes in the access cover Other fixtures to hold the probes can be designed The ob ject is to keep the reference probe and the probe s to be calibrated as closely grouped as possible in the working area of the bath Bath stability is maximized when the bath working area is kept covered In preparing to use the
86. people to safely move the bath The area con taining the compressors will be heavier than the rest of the bath DO NOT move a bath filled with fluid see Section 5 1 Moving or Uncrating the Bath BURN HAZARD e Extremely cold temperatures may be present in this equipment Freezer burns and frostbite may result if personnel fail to observe safety precau tions e High temperatures may be present in this equipment Fires and severe burns may result if personnel fail to observe safety precautions e The drain tube and dust cover of the Fluid Expansion Reservoir may be hot Handle them carefully and always be sure the drain tube is fully in serted into the elbow of the dust cover e The drain tube of the Fluid Expansion Reservoir is not designed to handle large flow rates encountered by overfilling the tank It is intended for ex panding fluid rates from heating only Fill tank only until the level reaches the top of the baffle see Figure 1 on page 14 ELECTRICAL HAZARD e These guidelines must be followed to ensure that the safety mechanisms in this instrument will operate properly This instrument must be plugged into a 230V AC electric outlet of the appropriate frequency The power cord of the instrument is equipped with a three pronged grounding plug for your protection against electrical shock hazards It must be plugged directly into a properly grounded three prong receptacle The receptacle must be installed in accordance with loc
87. personal in jury Carefully place probes on a heat cold resistant surface or rack until they are at room temperature It is advisable to wipe the probe with a clean soft cloth or paper towel before inserting it into another bath This prevents the mixing of fluids from one bath to another If the probe has been calibrated in liquid salt carefully wash the probe in warm water and dry completely before transferring it to another fluid Always be sure that the probe is completely dry before in serting it into a hot fluid Some high temperature fluids react violently to water or other liquid mediums Be aware that cleaning the probe can be dangerous if the probe has not cooled to room temperature Additionally high temperature fluids may ignite the paper towels if the probe has not been sufficiently cooled For optimum accuracy and stability allow the bath adequate stabilization time after reaching the set point temperature Comparison Calibration Comparison calibration involves testing a probe unit under test UUT against a reference probe After inserting the probes to be calibrated into the bath al low sufficient time for the probes to settle and the temperature of the bath to stabilize One of the significant dividends of using a bath rather than a dry well to cali brate multiple probes is that the probes do not need to be identical in construc 21 7381 Calibration Bath User s Guide 22 6 3 tion The fluid in the bath all
88. rcuitry may also be a possible cause Contact an Authorized Service Center see Section 1 3 on page 5 for assistance The bath does not achieve low Too much heating or not enough cooling can cause this problem temperatures Check that the control indicator glows green showing that the con troller is attempting to cool The heaters may be disabled as a test by temporarily removing the heater fuses Insufficient cooling may be caused by lack of refrigerant in the sys tem Contact an Authorized Service Center for assistance Comments EMC Directive Hart Scientific s equipment has been tested to meet the European Electromag netic Compatibility Directive EMCEMC Directive 89 336 EEC The Decla ration of Conformity for your instrument lists the specific standards to which the unit was tested The instrument was designed specifically as a test and measuring device Com pliance to the EMC directive is through IEC 61326 1 Electrical equipment for measurement control and laboratory use EMC requirements 1998 As noted in the IEC 61326 1 the instrument can have varying configurations The instrument was tested in a typical configuration with shielded RS 232 cables Immunity Testing The instrument was tested for laboratory locations Criterion B was used for Radiated RF IEC 61000 4 3 and Voltage dips short interruptions and voltage immunity tests IEC 61000 4 11 Criterion C was used for Electrostatic Dis charge ESD
89. reasing AAA Range over which a fume hood is recommended SS Decomposition Starts z BP Boiling Point CS Centistokes EP Evaporation Point fluid loss due to evaporation FL Flash Point FR Freeze Point PP Pour Point Figure 4 Chart of Various Bath Fluids and Their Properties Viscosity Points shown are at 50 and 10 centistokes viscosity When viscosity is greater than 50 centistokes stirring is very poor and the fluid is unsatisfactory for bath applications Optimum stirring generally occurs at 10 centistokes and below Fume Point Indicates the point at which a fume hood or ventilation system must be used to prevent health hazards posed by fume vapors In the graph it is assumed that the bath access hole is covered at this point This is subject to user s company policy Hart recommends the use of a ventilation system as 33 7381 Calibration Bath User s Guide 34 8 2 8 3 8 4 soon as the fluid produces vapors Keep the access hole covered to reduce evaporation Flash Point The point at which ignition may occur The point shown may be either the open or closed cup flash point Refer to the flash point discussion in Section 8 1 8 Safety Boiling Point At or near the boiling point of the fluid the temperature stability is difficult to maintain Fuming or evaporation is excessive Large amounts of heater power may be required to maintain the temperature because of the heat o
90. relay anytime the bath temperature is more than a certain amount above the set point temperature In addition to this protection the controller is also equipped with a separate thermocouple temperature monitoring circuit that shuts off the heater if the temperature exceeds the cutout set point The controller allows the operator to set the bath temperature with high resolu tion set the cutout temperature adjust the proportional band monitor the heater output power and program the controller configuration and calibration parameters The controller may be operated in temperature units of degrees Celsius or Fahrenheit The controller is operated and programmed from the front control panel using the four key switches and digital LED display Re mote digital operation with the controller is possible via the standard RS 232 serial port The controller may be optionally equipped with an IEEE 488 GPIB digital interface Operation of the controller using the front control panel is dis cussed following in Section 9 Controller Operaton Operation using the digital interface is discussed in Section 10 Digital Communication Interface When the controller is set to a new set point the bath heats or cools to the new temperature Once the new temperature is reached the bath usually takes 15 20 minutes for the temperature to settle and stabilize There may be a small over shoot or undershoot of about 0 5 C during this process Refrigeration Cooling i
91. res and most impor tantly protects the bath fluids from being heated beyond the safe operating temperature preventing hazardous vaporization breakdown or ignition of the liquid The cutout temperature is programmable by the operator from the front panel of the controller It must always be set below the upper temperature limit of the fluid and no more than 10 degrees above the upper temperature limit of the bath If the cutout is activated because of excessive bath temperature power to the heater is shut off and the bath cools The display flashes ut out and the message will be sent over the communication ports The bath cools until it reaches a few degrees below the cutout set point temperature At this point the action of the cutout is determined by the setting of the cutout mode parameter The cutout has two selectable modes automatic reset or manual reset If the mode is set to automatic the cutout automatically resets itself when the bath temperature falls below the reset temperature allowing the bath to heat up again If the mode is set to manual the heater remains disabled until the user manually resets the cutout The cutout set point may be accessed within the secondary menu Press SET and EXIT to enter the secondary menu and show the heater power Then press SET twice to access the cutout set point ser fexr Access heater power in secondary menu O 110 j Cutout set point To change the
92. rious Proportional Band Settings The optimum proportional band width depends on several factors among which are fluid volume fluid characteristics viscosity specific heat thermal conduc tivity heater power setting operating temperature and stirring Thus the pro portional band width may require adjustment for best bath stability when any of these conditions change Of these the most significant factors affecting the op timum proportional band width are heater power setting and fluid viscosity The proportional band should be wider when the higher power setting is used so that the change in output power per change in temperature remains the same The proportional band should also be wider when the fluid viscosity is higher because of the increased response time The proportional band width is easily adjusted from the bath front panel The width may be set to discrete values in degrees C or F depending on the selected units The optimum proportional band width setting may be determined by monitoring the stability with a high resolution thermometer or with the control ler percent output power display Narrow the proportional band width to the point at which the bath temperature begins to oscillate and then increase the band width from this point to 3 or 4 times wider Table 4 lists typical propor 9 Controller Operation Proportional Band tional band settings for optimum performance with a variety of fluids at se lected temperatures
93. rs including sign at the two calibration temperatures First set the bath to the lower set point t Wait for the bath to reach the set point and allow 15 minutes to stabilize at that temperature Check the bath stability with the thermometer When both the bath and the thermometer have stabilized measure the actual bath temperature and compute the temperature error err the actual bath tem perature minus the set point temperature For example set the bath to 0 C The bath reaches a measured temperature of 0 3 C giving an error of 0 3 C Next set the bath for the upper set point ty and after stabilizing measure the bath temperature and compute the error errg For example set the bath to 100 C the thermometer measures 100 1 C giving an error of 0 1 C Computing RO and ALPHA Before computing the new values for RO and ALPHA the current values must be known The values may be found by either accessing the probe calibration menu from the controller panel or by inquiring through the digital interface The user should keep a record of these values in case they may need to be re stored in the future The new values RO and ALPHA are computed by entering 65 7381 Calibration Bath User s Guide 66 11 4 the old values for RO and ALPHA the calibration temperature set points t and ty and the temperature errors err and erry into the following equations RY gt li e Ia ALPHA 1 R ty Ly 1 ALP
94. s provided by a compact cascade refrigeration system utilizing the ozone safe R 507 and R 508bHFC refrigerants Refrigeration is often not needed when the bath is above 45 to 60 C depending on the fluid used and whether the access cover is used The automated system automatically turns the system off when above 60 C The refrigeration system automatically changes modes depending upon bath temperature and operation needs as described be low The refrigeration system is activated when the switch on the front panel is turned on 35 7381 Calibration Bath User s Guide 36 If the bath is below the 60 C cutoff point and is set to a temperature above 60 C the refrigeration shuts off to protect it from overheating and creating ex cessive internal pressures If the bath is above 60 C and is set to a new temper ature below the cutoff temperature the refrigeration turns on again at 59 C When the bath is controlling at temperatures between the 60 C and 31 C the bath operates in a low cooling capacity mode with the hot gas bypass valve on HGb on The HGb system reduces the cooling capacity and helps to improve the bath stability within that temperature range Since more cooling capacity is generally required below 31 C the hot gas bypass is automatically turned off HGb off providing more cooling capacity When the bath is cooled and the new set point is at least 2 C below the current bath temperature the cooling turns to ma
95. selection and access the set point value 39 7381 Calibration Bath User s Guide 40 9 3 2 9 3 3 SET Accept selected set point memory Set point Value After selecting the set point memory and pressing SET the set point value may be adjusted in increments of 0 01 C or F The set point value is dis played with the units C or F at the left C 406 00 Set point 4 value in C If the set point value does not need to be changed press EXIT to resume dis playing the bath temperature Press UP or DOWN to adjust the set point value Increment display C 42 50 New set point value When the desired set point value is reached press SET to accept the new value and access the set point vernier If EXIT is pressed any changes made to the set point are ignored Accept new set point value Set point Vernier The user may want to adjust the set point slightly to achieve a more precise bath temperature The set point vernier allows one to adjust the temperature be low or above the set point by a small amount with very high resolution Each of the 8 stored set points has an associated vernier setting The set point vernier can be set in increments of 0 00018 C The vernier is accessed from the set point by pressing SET The vernier setting is displayed as a 6 digit num ber with five digits after the decimal point This is a temperature offset in de grees of the selected units C or F 0 0000
96. temperature must drop a few degrees below the cutout set point be fore the cutout can be reset Temperature Set point The bath temperature can be set to any value within the range and with resolu tion as given in the specifications The operator must know the temperature range of the particular fluid used in the bath and the bath should only be oper ated well below the upper temperature limit of the fluid In addition the cutout temperature should also be set below the upper limit of the fluid Setting the bath temperature involves three steps 1 selecting the set point memory 2 adjusting the set point value and 3 adjusting the vernier if desired Programmable Set points The controller stores 8 set point temperatures in memory The set points can be quickly recalled to conveniently set the bath to a previously programmed tem perature set point To set the bath temperature one must first select the set point memory This function is accessed from the temperature display function by pressing SET The number of the set point memory currently being used is shown at the left on the display followed by the current set point value 25 00 j Bath temperature in degrees Celsius i 25 6 Set point memory 1 25 0 C currently used To change the set point memory press UP or DOWN Increment memory 4 40 0 New set point memory 4 40 0 C NEWFREREEERRAS ER ERE BENEARREENRERRERN Press SET to accept the new
97. ters menu TIREN RE Press SET to enter the menu IEEE 488 Address The IEEE 488 interface must be configured to use the same address as the ex ternal communicating device The address is indicated by 9 Controller Operation Calibration Parameters 9 15 2 9 16 Add ee j Current IEEE 488 interface address Adjust the value with UP or DOWN and then use SET to set the address to the displayed value Add 15 New IEEE 488 interface address ANTES TASTE Transmission Termination The transmission termination character can be set to carriage return only line feed only or carriage return and linefeed Regardless of the option selected the instrument will interpret either a carriage return or a linefeed as a command ter mination during reception The termination parameter is indicated with EGS IEEE 488 termination nn EE MERA ahhh mre etree ett tery a Use SET to save the new selection Calibration Parameters The operator of the bath controller has access to a number of the instrument calibration constants namely CTO BO BG H L and HGbt These values are set at the factory and must not be altered The correct values are important to the accuracy and proper and safe operation of the bath These parameters should not be adjusted In the event the controller s memory fails the user may restore these values to the factory settings A list of these constants and their settings are s
98. th Preparation and Filling for specific instructions Follow all safety guidelines listed in the user s manual Calibration Equipment should only be used by Trained Personnel If this equipment is used in a manner not specified by the manufacturer the protection provided by the equipment may be impaired Before initial use or after transport or after storage in humid or semi hu mid environments or anytime the instrument has not been energized for 1 Before You Start Safety Information more than 10 days the instrument needs to be energized for a dry out period of 2 hours before it can be assumed to meet all of the safety re quirements of the IEC 1010 1 If the product is wet or has been in a wet environment take necessary measures to remove moisture prior to apply ing power such as storage in a low humidity temperature chamber operat ing at 50 C for 4 hours or more e Overhead clearance is required Do not place the instrument under a cabi net or other structure Always leave enough clearance to allow for safe and easy insertion and removal of probes e The instrument is intended for indoor use only e The bath is a precision instrument Although it has been designed for op timum durability and trouble free operation it must be handled with care Position the bath before the tank is filled with fluid by rolling it into place DO NOT attempt to lift the bath Due to the weight of the com pressors it may require two
99. to select this memory and access the set point value Access set point value t 25 00 i Current value of set point 1 25 00 C mus ieusubesssceacasseuerecasesageues 15 7381 Calibration Bath User s Guide 16 Press UP or DOWN to change the set point value Increment display c 30 00 New set point value Press SET to accept the new value and display the vernier value The bath be gins heating or cooling to the new set point SET Store new set point access vernier 0 00000 Current vernier value Press EXIT and the bath temperature will be displayed again fex Return to the temperature display ed ed SE Bath temperature display The bath heats or cools until it reaches the new set point temperature Turn off the cooling to reach and control at higher temperatures When setting the set point temperature be careful not to exceed the temperature limit of the bath fluid The over temperature cutout should be correctly set for added safety See Section 9 10 Cutout To obtain optimum control stability adjust the proportional band as discussed in Section 9 9 Proportional Band 5 Installation Moving or Uncrating the Bath 5 5 1 5 2 5 3 Installation A CAUTION Read Section 6 entitled BATH USE before placing the bath into service Moving or Uncrating the Bath The bath is equipped with casters and should be rolled It is not equipped with handles and is not designed to be lifted
100. upplied to the user on the Report of Test with the manual CAUTION DO NOT change the values of the instrument calibration con stants from the factory set values The correct setting of these parameters is important to the safety and proper operation of the instrument 55 7381 Calibration Bath User s Guide 56 9 16 1 9 16 2 9 16 3 9 16 4 The calibration parameters menu is indicated by CAL Calibration parameters menu sus ressassapestarassasseasaugaeeeay Press SET five times to enter the menu CTO Parameter CTO sets the calibration of the over temperature cutout This is not adjustable by software but is adjusted with an internal potentiometer This pa rameter is set at the factory BO and BG These parameters calibrate the accuracy of the instrument set point These are programmed at the factory Do not alter the value of these parameters If the user desires to calibrate the bath for improved accuracy adjust RO and ALPHA according to the procedure given in Section 11 Calibration Procedure H and L These parameters set the upper and lower set point limits of the bath Note A high limit H setting below the flash point of the fluid in the bath is highly recommended HGbt This parameter is the temperature where the hot gas bypass activates This pa rameter is factory set To insure the bath s best performance without damaging its compressor DO NOT alter the value of this parameter
101. ximum capacity HGb off until the bath is within about 0 5 C of the new set point This provides the fastest cool ing possible to achieve the new set point temperature When heating the bath and the new set point is at least 5 C above the current bath temperature the refrigeration turns off until the bath is about 1 5 C below the new set point This permits the maximum heating rate to reach the higher temperatures as quickly as possible When the scan rate is active this function is modified see Section 9 4 Scan on page 41 The cooling remains off at tem peratures above 60 C The automatic cooling mode may not be ideal for all circumstances The auto matic mode may be turned off permitting manual control These controls are available through the front panel as described in Section 9 13 Operating Pa rameters or through the digital interface as described in Sections 10 3 Inter face Commands and 10 4 Cooling Control The cooling mode control may be set to automatic on or off With these selections the refrigeration is either in automatic as described above always on or always off The hot gas bypass modes are similarly selectable between automatic on or off This system is ei ther in automatic as described above always on low cooling capacity adjustable or always off high cooling capacity The following situations benefit by changing cooling modes e Ifthe scan mode has been selected and the desired cooling scan requir
102. yed The baud rate of the bath may be programmed to 300 600 1200 or 2400 baud The baud rate is pre pro grammed to 2400 baud Use UP or DOWN to change the baud rate value Press SET to set the baud to the new value or EXIT to abort the operation and skip to the next parameter in the menu 10 1 2 2 Sample Period 58 The sample period is the next parameter in the menu and prompted with SANPLE The sample period is the time period in seconds between temper 10 Digital Communication Interface IEEE 488 Communication optional 10 1 2 3 10 1 2 4 10 1 3 10 2 10 2 1 ature measurements transmitted from the serial interface If the sample period is set to 5 the bath transmits the current measurement over the serial interface approximately every five seconds The automatic sampling is disabled with a sample period of 0 Press SET to choose to set the sample period Adjust the period with UP or DOWN Press SET to set the sample period to the new value or EXIT to abort and skip to the next parameter Duplex Mode The next parameter is the duplex mode indicated with d U P L The duplex mode may be set to half duplex HALF or full duplex FULL With full duplex any commands received by the bath via the serial interface are executed and immediately echoed or transmitted back to the device of origin With half duplex the commands are executed but not echo

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