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7312 Users Guide 5B2307.vp

1. gt T iiie Secondary Functions mper r emperature SET EXIT EE SET Y Y E EXIT Display Power l EXIT Reset Cutout SET I Y I Cutout Active SET EXIT Set Proportional Band l Y S SET 4 EXIT Select Setpoint Y SET E EXIT Set Cutout Temp SET EXIT Adjust Setpoint SET Y EXIT Adjust Vernier EXIT SET Y p Y 4 EXIT Set Scale C F Configuration Menu SET SET EXIT EXIT EXIT E 3 EXIT EXIT Probe gt Operating gt UP IEEE 488 u p Menu DOWN Parameters lt Ipoww Interface DOWN Interface Down H lt lt Menu lt Menu ro c SET SET SET l SET a ser X 5 Y Y Y a Y E Y Cutout i BAUD ME Device i DO i Rate D Address i g CTO SET EXIT SET EXIT SET EXIT SET EXIT iu SET EXIT 1 jd D 1 Adj Cutout Adjust Adj Device ee i I I I 1 I 1 SET EXIT SET EXIT l SET EXIT 1 SET EXIT 1 gt SET EXIT Y Po lt x DG Triple Point of i Sample gt Water Cutout Period S IEEE 488 i n SET EXIT gt SET EXIT SET EXIT i i Option Installed B SET L EXIT O lA i E 1 1 Adj Sample i Lu f SET EXIT SET EXIT SET EXIT i lt SETIEXIT i I Triple Point of i Duplex 1 2 L Water Set Point j Mode O SET EXIT SET EXIT i Z ser EXT i o 1 Adj Duplex i a 1 SET EXIT SET
2. Calibration 7312 Triple Point of Water Maintenance Bath User s Guide March 2013 2013 Fluke Corporation All rights reserved Specifications are subject to change without notice All product names are trademarks of their respective companies LIMITED WARRANTY AND LIMITATION OF LIABILITY Each Fluke product is warranted to be free from defects in material and workmanship under normal use and service The warranty period is one year and begins on the date of shipment Parts product repairs and services are warranted for 90 days This warranty extends only to the original buyer or end user customer of a Fluke authorized reseller and does not apply to fuses disposable batteries or to any product which in Fluke s opinion has been misused altered neglected contaminated or damaged by accident or abnormal conditions of operation or handling Fluke warrants that software will operate substantially in accordance with its functional specifications for 90 days and that it has been properly recorded on non defective media Fluke does not warrant that software will be error free or operate without interruption Fluke 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 Fluke Warranty support is available only if product is purchased through a Fluke authorized sales outlet or Buyer has paid the applicable internatio
3. Heat Transfert Fluid Voss oe oe erre a A 31 8 1 1 Temperature Rape lt a cs sg ai a we a Re RIE SS x 31 8 1 2 VISCOSIY oa e AE A AA ed 31 8 1 3 Specific Heat sore oue o coa dd 31 8 1 4 Thermal Conductivity ee ee ee ee 32 8 1 5 Thermal Expansion o o m s mm 32 8 1 6 Electrical Resistivity sor re oe 646546 844550 e 9 EG 33 8 1 7 Fluid Lifetime 2o 4586 rs bo 24 DR e bo de 33 8 1 8 Sa ac luos bue S p rue tee ews be ed Gea bos ob ded 33 8 1 9 gl E PTT 34 8 1 10 Commonly Used Fluids gt ss s e ss ee 34 SLOT Water a ai oda ie aide die Be ot Gp e il dei ca ace Gunes ara EAT EAE 34 5 1 10 2 Ethylene Glycols p atra RES ous a ars 34 1 10 5 Mineral Oil s ack omm kem xL EG RS SE ORE HE ERE EEE 34 8 1 10 4 Silicone OW uuu aurou e len aed mp Ue i EI a Cae es Rows Cercle owt ds 34 8 1 11 Fluid Characteristics Charts ee 35 8 1 11 1 Limitations and Disclaimer cs se d re be 20 00000000000 35 8 1112 About TS Graph asi ok Rp gue mago a ce eee od NY e ees EUR AC de 35 UEC y doi e mdi seg sca Se dra anh tod Se a ROK GG RRS 37 DOWBE os coe qeu bo e a ER ERE l 38 Heute chek eek whe a bo a ESS EARS 38 Temperature Controller v ro 3o y xke x vss 38 Refriger ti n uuu a sanp du gc ode ERE SEP HC GS R y d 39 9 Controller Operation 5 4 wae ee ee as Ml 9 1 9 2 9 3 9 4 9 5 9 6 9 7 Bath Temperature cs se saire 34 2 p enta aor a RSE was 41 Res t Kov P 41 Temperature SEDO e a a AR 43
4. 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 3 lists typical propor 47 7312 TPW Maintenance Bath User s Guide 48 tional band settings for optimum performance with a variety of fluids at se lected temperatures Table 3 Proportional Band Fluid Table 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 the SET and EXIT buttons to enter the secondary menu and show the heater power Then press the SET button to access the proportional band sx EXT Access heater power in secondary menu To change the proportional band pre
5. 5 GND 5GND 6NC 6 DSR 7 RTS ee 7 RTS 8 CTS A 8 CTS 9NC 9NC Instrument Computer DTE Connector Connector DB 9 Pin DB 25 Pin 1NC e 2 RxD e 2TxD 3TxD e 3RxD 4NC e 4RTS 5 GND ED GENS 5CTS 6NC 6 DSR 7 RTS A E 7 GND 8 CTS 2 8 DCD 9NC 20 DTR Figure 9 Serial Communications Cable Wiring Setup Before operation the serial interface of the bath must first be set up by pro gramming the BAUD rate and other configuration parameters These parame ters are programmed within the serial interface menu To enter the serial parameter programming mode first press the EXIT button while pressing the SET button and release to enter the secondary menu Press the SET button repeatedly until the display reads ProbE This is the menu selection Press the UP button repeatedly until the serial interface menu is in dicated with SErIAL Finally press the SET button to enter the serial pa rameter menu The serial interface parameter menu contains the BAUD rate the sample rate the duplex mode and the linefeed parameter BAUD Rate The BAUD rate is the first parameter in the menu The display prompts with the BAUD rate parameter by showing BAUd Press the SET button to choose to set the BAUD rate The current BAUD rate value is displayed The 10 Digital Communication Interface IEEE 488 Communication optional 10 1 2 2 10 1 2 3 10 1 2 4 10 1 3 10 2 BAUD ra
6. 95 1 Programmable Set points een 43 9 3 2 set point Valle x ogc ce Wh e ORO e E RE US 44 9 3 3 Setpoint Vefhi r x nox p 4o Op RU ES eu ew A RUE 44 Temperature scale Units ose uu Roe Sa Eo xx os 45 secondary Menu uw reu o eR ea Pe a RR X ges 46 Heater PONCE lt a ena i xeu ko qe e eps BUR E V Red 46 Proportional Band iu e sees Ree ER a s 46 9 8 9 9 9 10 9 11 9 12 9 13 9 14 10 Digital 10 1 10 2 10 3 10 4 Giu ER TRE TT ce eee e a a ce lada ina e ee Ae 49 Controller Configuration 0 ide ae Oe Bhd Oe 50 Probe Parameters eee 50 9 10 1 A LTD 50 9 10 2 poc 50 Operating Parameters do kar x RS ECC a 50 9 11 1 Cutout Reset Modes op ue al PARC Re E Wwe e sre 51 9 11 2 Triple Point of Water Cutout e 51 Serial Interface Parameters 52 9 12 1 BAUD Rat 3 6 6 sacados a Shee ts SE as a a 52 9 12 2 Sample Period ocios cion dete tee eG been Si S Rom m ed es 53 9 12 3 Duplex Mod6 2 s ach a ee a ee Ee a ee e ee eS 53 9 12 4 Tinefeed ces oko mono a ee Ew amo Te Re Bos dee Rs 53 IEEE 488 Parameters 0 0 0 0 000008 00 54 9 13 1 IEEE 488 Address 54 9 13 2 Transmission Termination een 54 Calibration Parameters 00000048 55 9 14 1 CTO a on ORE oO OE e a a a 55 9 14 2 Heatid L c ai ah ee a aa ee a ee ew ee 55 Communication Interface 57 Serial Communicati
7. Table 2 and Figure 6 on pages 36 and 37 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 to be used as a general guide in choosing a fluid Though every effort has been made to pro vide correct information we cannot guarantee accuracy of data or assure suit ability 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 garding flash points toxicity and such issues must be considered You are responsible f
8. mode is set to automatic the cutout automatically resets when the bath temper ature 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 re sets the cutout The cutout set point may be accessed within the secondary menu Press the SET and EXIT button to enter the secondary menu and show the heater power Then press the SET button twice to access the cutout set point ser T exr Access heater power in secondary menu CO HBE Cutout set point To change the cutout set point press the UP or DOWN button Decrement display ED 15C New cutout set point To accept the new cutout set point press the SET button 49 7312 TPW Maintenance Bath User s Guide 50 9 9 9 10 9 10 1 9 10 2 9 11 SET Accept cutout set point The next function is the configuration menu Press the EXIT button to re sume displaying 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 five sets of configuration parameters probe parameters op erating parameters serial interface parameters IEEE 488 interface parameters and controller calibration param
9. 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 35 C 41 95 F e ambient relative humidity maximum 80 for temperature lt 31 C de creasing linearly to 50 at 40 C e pressure 75kPa 106kPa 11 7312 TPW Maintenance Bath User s Guide e mains voltage within 10 of nominal e vibrations in the calibration environment should be minimized e altitudes less than 2 000 meters 12 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 6 Installation through Section 9 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 e 7312 Bath e Access Hole Cover and Components e Triple Point of Water Support Racks and Adapters e User s Guide e Report of Test e Drain Valve If you are missing any item please
10. the bath temperature deviates excessively from the set point due to varying external conditions This is because the power output changes very little with temperature and the con troller cannot respond very well to changing conditions or noise in the system 9 Controller Operation Proportional Band If the proportional band is too narrow the bath temperature may swing back and forth because the controller overreacts to temperature variations For best control stability the proportional band must be set for the optimum width WIS oa Proportional Band too Narrow Proportional Band too Wide Optimum Proportional Band A _ a a a Figure 8 Bath Temperature Fluctuation at Various 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 width are heater power setting and fluid viscosity The pro portional 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 be cause of the increased response time
11. the temperature errors err and erry into the following equations _ err t DO err t DO iD t t DO 0 H L erry PE pe t 1 DG ma H L For example if DO and DG were previously set for 25 229 and 186 9740 re spectively and the data for t ty erry and erry were as given above then the new values DO and DG would be computed as 25 831 and 188 220 respec tively Program the new values DO and DG into the controller The new con stants are used the next time the bath temperature is set Check the calibration by setting the temperature to tj and tjj and measuring the errors again If de sired the calibration procedure may be repeated again to further improve the accuracy Calibration Example The bath is to be used between 25 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 DO and DG are 25 229 and 186 974 respectively The calibration points are chosen to be 25 00 and 75 00 C The measured bath temperatures are 24 869 and 74 901 C respectively Refer to Figure 10 for applying the equa tions to the example data and computing the new probe constants Single Point Calibration When calibrating the bath for applications emphasizing a single temperature a single point calibration can be quicker easier and more accurate These appli cations include maintenance of a triple point of water cell near zero de
12. 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 lom 5001 6 5 300 C 1 9 300 C 2 4 500 C 1 7 500 C Limiting Factors b boiling point e high evaporation fl flash point fr freeze point v viscosity Flash point test oc open cup cc closed cup Very low water solubility ice will form as a slush from condensation below freezing other conditions We assume the bath is well covered at this point This is also subject to company policy 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 9 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 because of the heat of vaporization 36 8 General Operation Stirring 100 C 0 C 100 C 200 C 300 C 400 C 500 C 600 C ae Silicone Oi FL 302 C A 9 Silicone Oil 5014 10 CS FL 280 C Silicone Oil 5013 10CS FL
13. 232 C i i Silicone Oil 5012 kos FL 211 C AS PN ilicone Or 5010 Mali Im cs FL 133 C p AT 22 PEERS t i E Halocarbon EP 5019 ID Te 5011 Methanol MAGO FL 12 C BP Ethanol 10CS FL 16 C Ethylene Glycol A i 50 50 with H20 mR E BP Dynalene HF LO o 5022 10CS FL 60 C E i pN Bath Salt Decomposition Starts l Shaded area represents usable range of fluid starting at BP Boiling Point 50 centistokes Lighter shading represents decreasing CS Centistokes viscosity while vaporization and decomposition increase Guiana ae Point due to evaporation FL Flash Point FR Freeze Point PP Pour Point Black area represents liquid range with excessive viscosity r 7 Q 3 a Range over which a fume hood is recommended Figure 6 Chart of Various Bath Fluids and Their Properties 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 8 2 Stirring Stirring of 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 37 7312 TPW Maintenance Bath User s Guide 38 8 3 8 5 Power Power to the bath is provided by an AC mains supply Refer to Sect
14. 96 C fr 10 C fl cc 12C 1 3 35 C 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 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 150 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 81 125 C 0 57 125 C Silicone Oil Type 40 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 C fl cc 211 C 10 25 C 0 934 25 C 0 43 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 40 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 10 150 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
15. EXIT i SET EXIT Linefeed e i l SET EXIT gt Adjust Linefeed 1 i SET EXIT i Interface Figure 7 Controller Operation Flowchart 42 Option Installed 9 Controller Operation Temperature Set point 9 3 9 3 1 Press the SET button once more to reset the cutout SET Reset cutout This action also switches the display to the set temperature function To return to displaying the temperature press the EXIT button If the cutout is still in the over temperature fault condition the display continues to flash cutout The bath 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 liquid 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 t
16. Ending Temperature Ts Starting Temperature De Ending Depth Ds 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 Judgment 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 Ending temperature Te 300 C Starting temperature Ts 25 C Ending depth De 9 2 inches 8 General Operation Heat Transfer Fluid 8 1 7 Ds 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 1t may be important that little or no electrical leakage oc cur through the fluid In such conditions choose a fluid with very high electri cal resistivity Fluid Lifetime Many fluids degrade over time because of vaporization water absorption gel ling or chemical breakdown 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 ass
17. NOTE A fan must be placed in front of the condenser if the unit is oper ated with the side panels removed The unit requires the side panels to be installed for proper airflow across the condenser 71 13 Maintenance 13 Maintenance 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 The calibration instrument has been designed with the utmost care Ease of operation 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 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 A drop in the fluid level affects the stability of the bath Changes in fluid level are dependent upon several factors specific to the conditions in which the equipment is used A schedule cannot be outlined to meet each set of conditions Therefore the bath should be checked weekly and adjustments made as required e Hea
18. and actions that may damage the in strument being used 1 2 1 A WARNINGS To avoid possible electric 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 unit may cause unknown hazards to the user DO NOT use the unit 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 3 Bath 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 more than 10 days the instrument needs to be energized for a dry out 1 Before You Start Safety Information 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 degree centigrade for
19. 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 with a platinum resistance sensor in the con trol probe The signal is electronically compared with the programmable refer ence signal amplified and then passed to a pulse width modulator circuit which controls the amount of power applied to the bath heater The bath is op erable within the temperature range given in the specifications For protection against solid state relay failure or other circuit failure the micro controller au tomatically turns off the heater with a second mechanical relay anytime the bath temperature is more than a certain amount above the set point temperature As a second protection device the controller is also equipped with a separate thermocouple temperature monitoring circuit which shuts off the heater if the temperature exceeds the cutout set point 8 General Operation Refrigeration 8 6 The controller allows the operator to set the bath temperature with high resolu tion set the cutout 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 Fahr enheit The controller is operated and programmed
20. from the front control panel using the four key switches and digital LED display Remote digital operation with the controller is possible via the standard RS 232 serial port The control ler may be optionally equipped with an IEEE 488 GPIB digital interface Oper ation of the controller using the front control panel is discussed following in Section 9 Controller Operation Operation using the digital interface is dis cussed 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 10 15 minutes for the temperature to settle and stabilize There may be a small over shoot or undershoot of about 0 5 C Refrigeration Bath cooling below 50 C is provided by a compact refrigeration system The system utilizes the ozone safe R 134A refrigerant The refrigerant is metered through an automatic expansion valve to achieve bath temperatures as low as 5 C The evaporator and heater are sandwiched to the sides of the tank This provides the precision control over heat gains and losses required for high sta bility The refrigeration is not required to maintain the bath above 45 to 50 C Continuous use of the refrigeration above 50 C will damage the compressor The refrigeration may be used for short periods of time for cooling down the bath to a lower temperature Do not exceed 60 minutes cooling above 50 C 3
21. mode parameter 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 Leer SE Cutout reset mode parameter Press the SET button to access the parameter setting Normally the cutout is set for manual mode Cko rSt Cutout set for manual reset To change to automatic reset mode press the UP button and then the SET button LEgshHubo Cutout set for automatic reset Triple Point of Water Cutout The triple point of water cutout protects the TPW cell in case of system failure which may cause the bath to rapidly cool below the maintenance set point This could cause the cell to rupture due to the expansion of ice The cutout uses a thermistor probe sensor and disengages the refrigeration compressor If the probe is replaced the cutout board must be recalibrated See Section 12 The user may set the cutout temperature A typical set point is from 0 3 to 0 5 C If undesired trips occur the temperature may be reduced The adjustment range is 1 27 C from 0 C in 0 01 C increments The triple point of water cutout engages for three reasons 1 the controller does not send a watch dog signal to the cutout board controller lockup 2 the thermistor sensor is disconnected or opens or 3 the bath goes below the cutout set point This could be if the
22. termination charac ter within the IEEE 488 parameter menu This menu does not appear on baths not fitted with the interface The menu is indicated by IEEE IEEE 488 parameters menu ussnasuuauuanusaunuansuunuaunnenuuuuenr Press the SET button to enter the menu IEEE 488 Address IEEE 488 interface must be configured to use the same address as the external communicating device The address is indicated by unsnasuusuuenusanuansunuannenuauuaur Hdgdsee Current IEEE 488 interface address rca Adjust the value with the UP or DOWN button and then use the SET button to set the address to the displayed value RAdd 15 New IEEE 488 interface address nana 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 9 Controller Operation Calibration Parameters 9 14 9 14 1 9 14 2 instrument interprets either a carriage return or a linefeed as a command termi nation during reception The termination parameter is indicated with EGS IEEE 488 termination Use the SET button to save the new selection Calibration Parameters The operator of the bath controller has access to a number of the bath calibra tion constants namely CTO H and L These values are set at the factory and must not be altered The correct values are important to the accuracy and
23. the cutout circuit board the front panel must be removed Be sure to disconnect the power to the unit before beginning It is best to move quickly to avoid much bath temperature change Begin by removing the 4 screws attach ing the sloping controller panel Lift up the controller panel to access the fas teners attaching the front sheet metal panel Remove the two fasteners located at the top left and right corners of the panel The bottom of the panel is retained by a screw on either side of the panel that is in a key hole shaped slot Lift up the panel and wiggle slightly so that the screw heads come out through the larger portion of the slot The bottom screws are not to be removed Once the panel is removed set it aside and temporarily replace the controller panel rein stalling the screws to hold it in place Reestablish the power connection to the bath and allow the bath to regain stable control at the required set point This procedure takes 15 minutes or longer de pending on how long the bath has been off and how far it has drifted off tem perature Be aware that the bath has a low voltage line monitor that activates when the power is disconnected Several minutes are required before the unit is permitted to turn on Note the amber light on the back of the unit WARNING Shock hazard High Voltage power is accessible DM Identify the cutout PC board on the left side of a sheet metal shelf below the temperature controller boards Locate o
24. 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 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 the SET and EXIT button simultaneously and release The heater power is displayed as a percentage of full power EXT Access heater power in secondary menu Ie Pct Heater power in percent To exit out of the secondary menu press the EXIT button To continue on to the proportional band setting press the SET button exa 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 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 5 If the proportional band is too wide
25. 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 should be used As with most oils mineral oil expands as temperature in creases so be careful not to fill the bath too full that it overflows when heated The viscosity and thermal characteristics of mineral oil is poorer than water so temperature stability is not as good Mineral oil has very low electrical conduc tivity Use caution with mineral oil since it is flammable and may also cause se rious injury if inhaled or ingested 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 8 General Operation Heat Transfer Fluid 8 1 11 8 1 11 1 8 1 11 2 characteristics which are somewhat poorer than water The viscosity changes significantly with temperature and also causes thermal expansion to occur These oils have very high electrical resistivity Silicone oils are fairly safe and non toxic Silicone oils are fairly expensive Fluid Characteristics Charts
26. 4 hours or more e DO NOT operate high temperature baths 500 C near flammable materi als Extreme temperatures could ignite the flammable material 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 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 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 115 VAC 60Hz 230 VAC 50Hz optional AC only electric outlet 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 local codes and ordi nances Consult a qualified electrician DO NOT use an extension cord or adapter plug e DO use a ground fault interrupt device This unit contains a liquid A ground fault device is advised in case liquid is present in the electrical syst
27. 440 8442 F oS ESS GSES 13 4 2 DeL UD e uox wa BSE ES Rae eee EE eR eS ERE 13 4 3 POWDER xu 6646042 PE SEX n p dd eee die dox 14 44 Setting the Temperature o cc 09 9 9 3089 ad 14 s Installation ad ae ce cR A 17 3s Bath Environment a de dx E xS xd e RR Aou UE emt UA 17 5 2 Dry out Period 2 deme he hb A KER A OR Sox Rw d 17 5 3 Bath Preparation and Filling 17 5 3 1 Drain Valve Installation Instructions 2l 17 2 9 2 Pulls With PIs uuu uc gehe wee DDR OE P Wow s 18 5 4 POWBE 24 aia 4k Ge oun a Ra SE GREE REE EO 19 6 Ball USE uus ETE RUE EHE Roe hee wd exu xv 6 1 General s a dtes d us hoe oes d ee PR MEE et Ed 21 6 2 Triple Point of Water Cell Maintenance 21 6 2 1 Bath Preparation 2 oae ooo ea y oe Ro hm ee s 21 6 2 2 Setting the Bath Temperature lees 22 6 2 3 Adjusting the TPW Cell Rack lens 22 6 2 4 Fluid Level ss sais mos ae teh ee a aa OS eS 22 6 2 5 Features of the Bath Access Cover llle 24 6 2 6 Maintenance of the TPW Cell ee ee 24 6 3 6 4 Comparison Calibration esten reses tas ses 27 Calibration of Multiple Probes 27 7 Parts and Controls 29 7 1 dee 7 3 Front Panel eos oce wa ee 29 Bath Tank and Lid a e leen 30 Back Panel 30 8 General Operation 000 woo e esses xw Ad 8 1 8 2 8 3 8 4 8 5 8 6
28. 4U43423 234 71 12 9 UME coe ovde y oue OP RR aR G S 4S A RENE x 71 13 M i t naice 24 06 44 mb bw SSS EHC Om cw E men 73 14 Troubleshooting 2 2 22 o Ro RR 75 14 1 Troubleshooting Ls ox oko o e e 99g 75 hi2 CODD 20x Ro x e E E og GOS 78 14 2 1 EMG Directive seno a Bh a ee SS ACA E P WE EE ads 78 14 2 2 Low Voltage Directive Safety len 78 Figures and Tables Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Drain Valve Installation IMPORTANT Do Not Over Tighten Follow the installation instructions above Details of the Access Cover and Cell Racks 2 924 m n Fluid Estel ds re Mie ka a a wee Location of Handles for NBS Design Cells Front Controller Panal 1 55 ia er ee eS Chart of Various Bath Fluids and Their Properties Controller Operation Flowchart 22 22 GE Ro REGE Bath Temperature Fluctuation at Various Proportional Band Settings Serial Communications Cable Wiring Sample Calibration Computations 444 6244 44 84 4a ee 4 vi Tables Table 1 Table 2 Table 3 Table 4 Table 4 International Electrical Symbols o oo 1 Table of Various Bath Fluids and Their Properties 36 Proportional Band Fluid Table 5 5 222922 o mn 48 Interface Command Summary cese er nnn 61 Interface Command Summary continued 62 1 Before Yo
29. 5 0 8 inches below the bottom of the lid NOT the access cover Power Plug the bath power cord into a mains outlet of the proper voltage frequency and current capability 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 unit Turn the bath on using the front panel POWER switch The baths turns on and begins to heat or cool to reach the previously programmed temperature set point The front panel LED display indicates the actual bath temperature Set the cooling switch to OFF for tem perature above approximately 45 C Set the switch to ON for lower temperatures 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 t Bath temperature display When the SET button is pressed the display shows the set point memory that 1s currently being used and its value Eight set point memories are available SET Access set point
30. 9 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 4 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 shown on the dis play The units C or F of the temperature value are displayed at the right For example 5 00 C 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 the temperature display alter nately flashes cut out i Indicates cutout condition The message continues to flash until the temperature is reduced and the cutout is reset The cutout has two modes automatic reset and manual reset The mode deter mines how the cutout is reset which allows the bath to heat up again When in automat
31. 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 antng Osinga fluke com When contacting these Service Centers for support please have the following information available e Model Number 1 Before You Start Authorized Service Centers e Serial Number e Voltage e Complete description of the problem 2 Introduction Introduction The Hart Scientific Model 7312 is a floor standing constant temperature bath This bath is useful in maintaining up to two triple point of water cells perform ing temperature calibration and other applications requiring stable tempera tures An innovative state of the art solid state temperature controller has been incorporated which maintains the bath temperature with extreme stability The temperature 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 serial interface and optional with an IEEE 488 interface Temperature cutouts protect triple point of water cells from freezing or high temperatures due to system failure Separate circuits cut off heating or refriger ation independent of the temperature controller This bath was designed to be compact and low cost without compromising per formance The bath operate
32. RRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE FLUKE SHALL NOT BE LIABLE FOR ANY SPECIAL INDIRECT INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOSSES INCLUDING LOSS OF DATA ARISING FROM ANY CAUSE OR 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 or other decision maker of competent jurisdiction such holding will not affect the validity or enforceability of any other provision Fluke Corporation Fluke Europe B V P O Box 9090 P O Box 1186 Everett WA 98206 9090 5602 BD Eindhoven U S A The Netherlands 11 99 Table of Contents 1 Before You Salteras OO EROR AAA 1 1 1 Symbols Used pe ue oce mie ds epa a ERU cee a e 1 1 2 Safety Information oe erre da A em 2 1 2 1 WARNINGS 5 6 a Woo a A he Bo ee Ae HA AT e 2 1 2 2 CAUTIONS 4 lo bi wey omg d 2 one Ch Rede ke ee Bae BS 4 13 Authorized Service Centers 54424 owe eR X S 5 2 Introduction sss esaw oo e as ok A 9 3 Specifications and Environment Conditions 11 3 1 sicuri MP 11 3 2 Environmental Conditions o oo 000 11 4 Ouick Start lt 4 2 6 66 lt 6 net 9X REGRESS AES 13 4 1 Unpack 26254525
33. S 232 serial interface which is standard and the IEEE 488 GPIB interface 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 OFF 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 10 Controller Operation with the exception of the BAUD rate setting The serial interface op erates with eight data bits one stop bit and no parity Wiring The serial communications cable attaches to the bath through the DB 9 connec tor at the back of the instrument Figure 9 shows the pin out of this connector 57 7312 TPW Maintenance Bath User s Guide 58 10 1 2 10 1 2 1 and suggested cable wiring To eliminate noise the serial cable should be shielded with low resistance between the connector DB 9 and the shield RS 232 Cable Wiring for IBM PC and Compatibles Instrument Computer DTE Connector Connector DB 9 Pin DB 9 Pin 1NC 1DCD O A DA 3TxD 9 3TxD 4NC e 4 DTR
34. Section 5 3 page 17 for drain installation instructions 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 DO NOT overfill the bath Overflowing liquid may damage the electrical system Be sure to allow for thermal expansion of the fluid as the bath temperature increases See Section 5 3 Bath Preparation and Filling for specific instructions Read Section 7 Bath Use before placing the unit into service 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 unit 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 unit 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 must have a copy 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 The unit is a precision instrument Although it has been designed for opti mum durability and trouble free operation it must be handled with care Positi
35. alue can be set with a resolution of 0 01 C 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 below or above the set point by a small amount with a very high resolution Each of the eight stored set points has an associated vernier setting The vernier is accessed from the set point by pressing the SET button The vernier setting is displayed as a six digit number with five digits after the decimal point This is a temperature offset in degrees of the selected units C or F 0 00000 Current vernier value in C To adjust the vernier press the UP or DOWN button Unlike most func tions the vernier setting has immediate effect as the vernier is adjusted The SET button need not be pressed This allows one to continually adjust the bath temperature with the vernier as it is displayed 4 WB New set point memory 4 40 0 C nana cnn 9 Controller Operation Temperature Scale Units 9 4 Next press the EXIT button to return to the temperature display or the SET button to access the temperature scale units selection SET Access scale units 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 T
36. an Electromag netic Compatibility Directive EMC Directive 89 336 EEC The Declaration of Conformity for your instrument lists the specific standards to which the unit was tested 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
37. call an Authorized Service Center for assistance Set Up CAUTION The drain valve must be installed on the back of the bath be fore attempting to fill the tank with fluid See Section 5 3 on page 17 for drain installation instructions 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 unit 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 8 Cutout Set up of the bath requires careful unpacking and placement of the bath filling the bath with fluid and connecting power Consult Section 6 Installation for 13 7312 TPW Maintenance Bath User s Guide 14 4 3 4 4 detailed instructions for proper installation of the bath Be sure to place the bath in a safe clean and level location Fill the bath tank with an appropriate liquid For operation at moderate bath temperatures clean distilled water works well above 0 C and below 70 C Carefully pour the fluid into the bath tank through the large rectangular access hole above the tank avoiding spilling any fluid The fluid must not exceed a height of 12 7 20 3 mm 0
38. carriage return character The in terface makes no distinction between upper and lower case letters hence either may be used Commands may be abbreviated to the minimum number of let ters 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 cr re turns the current set point and an s 50 00 lt cr gt sets the set point to 50 00 degrees In the following list of commands characters or date within brackets and are optional A slash denotes alternate characters or data Numeric 10 Digital Communication Interface Interface Commands Table 4 Interface Command Summary Command Command Returned Acceptable Command Description Format Example Returned Example Values Display Temperature Read current set point s etpoint S set 9999 99 C or F set 100 000 C Set current set point to n s etpoint n s 100 Instrument Range Read vernier v ernier V v 9 99999 v 0 00000 Set vernier to n v ernier n v 00001 Depends on Configuration Read temperature t emperature t t 9999 99 C or F t 55 69 C Read temperature units u nits u u X uc Set temperature units u nits c f CorF Set temperature units to Celsius u nits c u C Set temperature units to u nits
39. d cooling The proportional band may require some adjustment depending on the specific heat of the fluid 31 7312 TPW Maintenance Bath User s Guide 8 1 4 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 8 1 5 Thermal Expansion 32 Thermal expansion describes how much the volume of the fluid changes with temperature Thermal expansion 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 Table of Bath Fluids Fluid manufacturers can also provide this information The ther mal expansion coefficients are shown in units of cm cm C however the values are the same for any units of length Divide the value by 1 8 for F coefficients The following equation may be used to find the desired depth De Ds K Te Ts 1 Or Ds De K Te Ts 1 where De lt or The Maximum Fill Depth Where K Expansion coefficient Te
40. e 34 8 1 9 8 1 10 8 1 10 1 8 1 10 2 8 1 10 3 8 1 10 4 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 a very low viscosity and good thermal conductivity and heat capacity which make it among the best flu ids 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 conduc tivity of water may prevent its use in some applications Water has a limited temperature 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 algaecide chemical in the water to prevent contamination 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
41. e bath This improves bath temperature stability prevents excess fluid evaporation or fumes and increases safety with hot fluid The triple point of water cell maintenance access cover provides thermometer wells for precooling and access to the TPW cells See Section 6 2 6 Mainte nance of the TPW Cell 7 3 Back Panel On the back of the bath are the system fuses removable power cord high low voltage indicator drain serial port and IEEE 488 port if installed 30 8 General Operation Heat Transfer Fluid 8 1 8 1 1 General Operation Heat Transfer Fluid Many fluids work with 7312 bath Choosing a fluid requires consideration of many important characteristics of the fluid Among 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
42. e bath into an AC mains outlet of the appropriate voltage frequency and current capacity 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 unit 19 6 Bath Use General 6 6 1 6 2 6 2 1 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 Some of the information in this text may not apply to the specific bath you have purchased 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 9 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 stres
43. e 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 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 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 27 7 Parts and Controls Front Panel 7 1 Parts and Controls Front Panel The following controls and indicators are present on the controller front panel see Figure 5 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 HEATER MODE COOLING 0 Figure 5 Fro
44. e width of the proportional band until the temperature sta bilizes Refer to Section 9 7 The bath does not Insufficient cooling This may be caused by lack of refrigerant because of a achieve low temperatures leak in the system Refer to Section 12 Charging Instructions 77 7312 TPW Maintenance Bath User s Guide 78 14 2 14 2 1 14 2 2 Problem Causes and Solutions The controller does not maintain controller pa rameters or parameters 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 instrument 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 f the display shows InIT and or the cycle count shows a low number such as 0002 the battery is spent and should be replaced Contact an Authorized Ser vice Center for assistance 5 After replacing the battery you must reprogram the calibration and user ad justable parameters into the controller Comments EMC Directive Hart Scientifics equipment has been tested to meet the Europe
45. elting inappropriately 26 6 Bath Use Comparison Calibration 6 3 6 4 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 tion The fluid in the bath allows 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 slid over the probe before inserting it in the bath or as complicated as a specially designed reflectiv
46. em and could cause an electrical shock e 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 e 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 e Fluids used in this unit 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 7312 TPW Maintenance Bath User s Guide 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 unit opera tion 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 8 Cutout 1 2 2 A CAUTIONS To avoid possible damage to the instrument follow these guidelines THE DRAIN VALVE MUST BE INSTALLED ON THE BACK OF THE BATH BEFORE ATTEMPTING TO FILL THE TANK WITH FLUID See
47. emperature first select the set point memory This function is accessed from the temperature display function by pressing the SET button 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 t Bath temperature in degrees Celsius SET Access set point memory 25 0 Set point memory 1 25 0 C currently used To change the set point memory press the UP or DOWN button Increment memory Press the SET button to accept the new selection and access the set point value SET Accept selected set point memory 43 7312 TPW Maintenance Bath User s Guide 44 9 3 2 9 3 3 Set point Value The set point value may be adjusted after selecting the set point memory and pressing the SET button The set point value is displayed with the units C or F at the left c 40 00 Set point value in C If the set point value does not need to be changed press the EXIT button to resume displaying the bath temperature Press the UP or DOWN button to adjust the set point value Increment display t 42 50 New set point value When the desired set point value is reached press the SET button to accept the new value and to access the set point vernier If the EXIT button is pressed instead any changes made to the set point are ignored SET Accept new set point value Set point Vernier The set point v
48. er 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 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 115 VAC Voltage Cutout 12 5 101 129 VAC Voltage Cut In 7 5 106 124 VAC 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 Telefax 1 801 763 1010 7312 TPW Maintenance Bath User s Guide E mail support hartscientific com Fluke Nederland B V Customer Support Services Science Park Eindhoven 5108 5692 EC Son NETHERLANDS Phone 31 402 675300 Telefax 31 402 675321 E mail ServiceDesk Q 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 hanOfluke com cn Fluke South East Asia Pte
49. erial interface The parameters in the menu are BAUD rate sample period duplex mode and linefeed BAUD Rate The BAUD rate is the first parameter in the menu The BAUD rate setting de termines the serial communications transmission rate The BAUD rate parameter is indicated by BRUd Serial BAUD rate parameter Press the SET button to choose to set the BAUD rate The current BAUD rate value is displayed ie Dt b l Current BAUD rate The BAUD rate of the bath serial communications may be programmed to 300 600 1200 or 2400 BAUD Use the UP or DOWN button to change the BAUD rate value 2400 b New BAUD rate rana 9 Controller Operation Serial Interface Parameters 9 12 2 9 12 3 9 12 4 Press the SET button to set the BAUD rate to the new value or the EXIT button to abort the operation 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 Serial sample period parameter Press the SET button to choose to set the sample period The current sample p
50. eriod value is displayed SA i Current sample period seconds rc Adjust the value with the UP or DOWN button and then use the SET button to set the sample rate to the displayed value SA 60 New sample period anna 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 immediately echoed or transmitted back to the device of origin With half duplex the commands are executed but not echoed The du plex mode parameter is indicated by anna DUP FULL Current duplex mode setting nc The mode may be changed using the UP or DOWN button and then press ing the SET button nro 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 53 7312 TPW Maintenance Bath User s Guide 54 9 13 9 13 1 9 13 2 ASCII 10 after transmission of any carriage return The linefeed parameter is indicated by nana LF 0n Current linefeed setting The mode may be changed using the UP or DOWN button and then press ing the SET button LES E New linefeed setting rra 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
51. erties of water while reducing the freezing point to a useable level The 21 7312 TPW Maintenance Bath User s Guide 22 6 2 2 6 2 3 6 2 4 mixture is also inexpensive and not flammable Pure denatured ethanol or other alcohols may be used directly but they can pose a fire hazard Ethylene glycol is not recommended because it leaves a sticky residue requiring cleaning of the thermometers immersed into it Be sure the over temperature and the water triple point cutouts are properly set See Sections 10 8 and 10 11 2 Setting the Bath Temperature The actual bath temperature must be from 0 007 to 0 008 C Use an accurate thermometer capable of reading to three decimal places to set the temperature While the bath may be calibrated to an extent see Section 12 the set point ac curacy by itself is not sufficient Check the reference thermometer against the TPW to assure accuracy of the temperature setting The resolution of the digital temperature setting is to 0 002 C The set point vernier feature of the tempera ture controller see Section 10 3 3 is helpful here The temperature of the bath needs to be checked occasionally over the first hour to ensure that control at the required temperature is established Check the bath temperature occasionally over a few weeks to verify that it has not drifted as well The condition of the ice mantle must be monitored regularly If the mantle seems to be growing increase the temperatu
52. et water triple point cutout tpsp n tpsp 0 33 1 27 C set point 2 28 F Serial Interface Menu Read serial sample setting sa mple sa sa 9 sa 1 Set serial sampling setting ton sa mplej 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 plex f ull du f Set serial duplex mode to half du plex h alf du h Set serial linefeed mode lf eed on of f ON or OFF Set serial linefeed mode to on Iffeed on If on Set serial linefeed mode to off If eed of f If of Calibration Menu Read low set point limit value tllow tl tl 999 tl 80 Set low set point limit to n tllow n tl 80 5 to 25 C Read high set point limit value th igh th th 999 th 205 Set high set point limit to n th igh n th 205 25 to 110 C Miscellaneous not on menus Read firmware version number ver sion ver ver 9999 9 99 ver 2100 3 56 Read structure of all commands h elp h list of commands Read Refrigeration f2 12 f2 9 12 0 Set Refrigeration f2 1 0 0 or 1 Set Refrigeration to on f2 n f2 1 Set Refrigeration to off f2 n f2 0 Legend Note Optional Command data Returns either information n Numeric data supplied by user 9 Numeric data returned to user x Character data returned to user 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 colu
53. eter to the bath temperature in order to prevent melting the ice mantle in the TPW cell Melting the mantle reduces its lifetime requiring it to be refrozen sooner Each well has a rubber shock guide at the top to help reduce shock strain to the del icate platinum sensor in an SPRT Underneath the cover a guide tube helps to prevent the thermometer from contacting internal parts If the thermometer is longer than 20 inches the user must retain it to prevent it from striking the bottom The two wells in the front permit thermometers to gain access to the TPW cells They also feature the rubber shock guide and guide tube The shock guide and guide tube are removable as an assembly to permit shorter thermometers to be more fully immersed into the cell Maintenance of the TPW Cell The TPW cells may be maintained for days to months depending upon care and maintenance and usage of the cell The following steps are typical 1 Set up the bath and cells as described above 2 Pre cool the cell to the bath temperature prior to freezing the mantle 3 Freeze the cell according to the manufacturers instructions 4 Fill the reentrant tube of the cell with chilled bath fluid to a level suffi cient to reach the cells water level when a thermometer is inserted 5 Insert the cell carefully into the bath Be certain that bottom of the cell is seated on the bottom plate grommet 6 Verify the bath fluid level is adequate The cell may be held in
54. eters The menus are selected using the UP and DOWN buttons and then pressing the SET button Probe Parameters The probe parameter menu is indicated by PrObE i Probe parameters menu Press the SET button to enter the menu The probe parameters menu contains the parameters DO and DG which characterize the resistance temperature rela tionship of the thermistor control probe These parameters may be adjusted to improve the accuracy of the bath This procedure is explained in detail in Sec tion 11 The probe parameters are accessed by pressing the SET button after the name of the parameter is displayed The value of the parameter may be changed us ing the UP and DOWN buttons After the desired value is reached press the SET button to set the parameter to the new value Pressing the EXIT button causes the parameter to be skipped ignoring any changes that may have been made DO This probe parameter refers to the resistance of the control probe at 0 C Nor mally this is set for 25 2290 ohms DG This probe parameter refers to the average sensitivity of the probe between 0 and 100 C Normally this is set for 186 7940 Operating Parameters The operating parameters menu is indicated by 9 Controller Operation Operating Parameters 9 11 1 9 11 2 PAr Operating parameters menu Press the UP button to enter the menu The operating parameters menu con tains the cutout reset
55. f u f Fahrenheit Secondary Menu Read proportional band setting pr op band pr pr 999 9 pr 15 9 Set proportional band to n pr op band n pr 8 83 Depends on Configuration Read cut out setting c utout C c 9999 x xxx c 110 C in Set cut out setting c utout n r eset Set cut out to n degrees c utout n c 110 Temperature Range Reset cut out now c utout r eset c r Read heater power po wer po po 9999 po 1 duty cycle Configuration Menu Probe Menu Read DO calibration parameter d0 d0 d0 999 9999 d0 25 2290 Set DO calibration parameter ton d0 n d0 25 2290 999 9999 to 999 9999 Read DG calibration parameter dg dg dg 999 9999 dg 186 9740 Set DG calibration parameter to n dg n dg 186 9740 999 9999 to 999 9999 Operating Parameters Menu Read cut out mode cm ode cm cm Xxxx cm AUTO Set cut out mode cm ode r eset a uto RESET or AUTO Set cut out to be reset manually cm ode r eset cm r 61 7312 TPW Maintenance Bath User s Guide Interface Command Summary continued Command Command Returned Acceptable Command Description Format Example Returned Example Values Set cut out to be reset cm ode a uto cm a automatically Read water triple point tpco tpco tpco ON or OFF tpco ON Set water triple point tpco ON OFF tpco ON ON or OFF Read water triple point cutout tpsp n tpsp tpsp 99 99C tpsp 0 31C set point S
56. face menu is the linefeed mode This pa rameter enables On or disables OFF transmission of a linefeed charac ter LF ASCII 10 after transmission of any carriage return The default setting is with linefeed on The mode may be changed using UP or DOWN and pressing SET Serial Operation Once the cable has been attached and the interface set up properly the control ler immediately begins transmitting temperature readings at the programmed 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 inter face commands are discussed in Section 11 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 59 7312 TPW Maintenance Bath User s Guide 60 10 2 1 10 2 1 1 10 2 1 2 10 2 2 10 3 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 transmission termination character To enter the IEEE 488 parameter programming menu press the EXIT and the SET button simultaneously and then release to enter the secondary menu Press the SET butto
57. grees Celsius or for the gallium point near 30 C An adjustment of only the DO cali bration constant is made in this process The advantage of calibration is to have the bath set point temperature more closely reflect the desired bath tempera ture While this procedure improves the accuracy at a specific set point the re sults may not be accurate enough alone to make the baths final temperature adjustment For example for the maintenance of a triple point of water cell the bath temperature must be known to within one thousandth of a degree Celsius The calibration of the bath is not intended to get that close Final adjustments 11 Calibration Procedure Measuring the Set point Error DO 25 229 DG 0 0028530 tj 25 00 C measured t 24 869 C ty 75 00 C measured t 74 901 C Compute errors err 24 869 25 00 C 0 131 C erry 74 901 75 00 C 0 099 C Compute DO DO _ 013 75 0 25 229 0 099 25 0 25 229 25 229 25392 75 0 25 0 Compute DG DG _ 0 099 0 131 A 0 0028530 0 0028548 75 0 25 0 Figure 10 Sample Calibration Computations 11 6 must be made using a thermometer and readout capable of making measure ments to one thousandth of a degree Measuring the Set point Error The first step in this procedure is to measure the set point error including the sign at the desired temperature Set the bath to the desired
58. h tempera ture drops and it is manually reset the cutout circuitry may be faulty Try per forming the Factory Reset Sequence explained below Factory Reset Sequence Hold the SET and EXIT keys down at the same time while powering up the unit The display shows init the model number and the firmware version Each of the controller parameters and calibration con stants must be re programmed The values can be found on the Report of Test that was shipped with the instrument The display flashes CUTOUT alternately with an incorrect process temperature Low battery A problem could exist with the memory back up battery If the bat tery voltage is insufficient to maintain the memory data may become scrambled causing problems A nearby large static discharge may also affect data in mem ory Access the battery by removing the L shaped panel covering the display electronics Corrupt controller memory If the problem reoccurs after the battery is re placed initialize the memory by performing a Factory Reset Sequence de scribed in a previous solution The controller displays the wrong temperature and the bath continually heats or cools regardless of the set point value Defective control probe The bath control probe may be disconnected burned out or shorted Check first that the probe is connected properly to the connec tor J2 of the analog board The probe may be checked with an ohmmeter to see
59. he calibration procedure is to measure the temperature errors 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 bath tem perature with the thermometer and compute the temperature error erry which is the actual bath temperature minus the set point temperature For example if the bath is set for a lower set point of t 20 C and the bath reaches a measured temperature of 19 7 C then the error is 0 3 C Next set the bath for the upper set point ty and after stabilizing measure the bath temperature and compute the error erry For example suppose the bath was set for 80 C and the thermometer measured 80 1 C giving an error of 0 1 C Computing DO and DG Before computing the new values for DO and DG 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 65 7312 TPW Maintenance Bath User s Guide 66 11 4 11 5 The user should keep a record of these values in case they may need to be re stored in the future The new values DO and DG are computed by entering the old values for DO and DG the calibration temperature set points t and ty and
60. he temperature scale units selection is accessed after the vernier adjustment function by pressing the SET button From the temperature display function access the units selection by pressing SET 4 times ES Bath temperature SET Access et point memory ke5 Set point memory SET Access set point value SET Access vernier 000000 Vernier sering SET Access scale units selection L Uez D d Seale units currently selected Press the UP or DOWN button to change the units Change units Un F New units selected Press the SET button to accept the new selection and resume displaying the bath temperature SET Set the new units and resume temperature display 45 7312 TPW Maintenance Bath User s Guide 46 9 5 9 6 9 7 Secondary Menu Functions which are used less often are accessed within the secondary menu The secondary menu is accessed by pressing the SET and EXIT buttons si multaneously 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
61. 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 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 creating a more uniform tem perature throughout the bath This improves the bath response time allowing it to maintain a more constant temperature For good control the viscosity should be less than 10 centistokes Fifty centistokes is about the practical upper limit of allowable viscosity Viscosity greater than this causes very poor control sta bility because of poor stirring and may also overheat or damage the stirring mo tor Viscosity may vary greatly with temperature especially with oils When using fluids with higher viscosities the controller 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 It also affects the heating and cooling rates Generally a lower specific heat means quicker heating an
62. ic mode the cutout resets itself as soon as the temperature is lowered below the cutout set point With manual reset mode the cutout must be reset 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 the display flashes cutout until the user resets the cutout To access the reset cut out function press the SET button SET Access cutout reset function The display indicates the reset function RESET Cutout reset function 41 7312 TPW Maintenance Bath User s Guide
63. if it is open or shorted The probe is a platinum 4 wire Din 43760 type The probe connector resistance should read 9 4K ohms between pins 1 and 3 3 2 K ohms between pins 3 and 4 12 4K ohms between pins 1 and 4 and no current on pin 2 Corrupt controller memory Initialize the memory by performing a Factory Re set Sequence described in a previous solution 14 Troubleshooting Troubleshooting Problem Causes and Solutions The controller controls or attempts to control at an inaccurate temperature Ifthe controller appears to operate normally except that the bath s temperature does not agree with the temperature measured by the user s reference ther mometer to within the specified accuracy consider the following Erroneous parameters Check that the calibration parameters are all correct according to the Report of Test If not reprogram the constants If the controller does not keep the correct parameters the memory backup battery may be weak causing errors in data See Low Battery in a previous solution Poor uniformity There may be an actual difference between the bath s control probe and the reference thermometer due to excess gradients in the bath Check that the bath has an adequate amount of fluid in the tank and that the stirrer is operating properly Also check that the reference thermometer and control probe are both fully inserted into the bath to minimize temperature gradi ent errors Defective con
64. improve the accuracy Calibrating the Triple Point of Water Cutout The under temperature cutout is provided to protect the triple point of water cell in case there is a temperature controller or sensor failure that would cause the bath to cool rapidly below the set point temperature Such a failure could cause the cell to rupture due to rapid expansion of the ice inside it The cutout deactivates the refrigeration thereby preventing the problem CAUTION Only trained personnel should operate calibration equipment The cutout is calibrated at the triple point temperature at the factory It may need to be recalibrated from time to time if there is drift in the cutout tempera ture or if the cutout probe has been replaced The actual cutout temperature may be observed by setting the bath to a temperature well below the cutout set point and monitoring the bath temperature until the cutout activates When the display flashes E P c out note the temperature If the error is less than 0 5 C it may be compensated for by resetting the water triple point cutout For greater errors it may be best to recalibrate the cutout 11 Calibration Procedure Calibrating the Triple Point of Water Cutout The cutout is calibrated by adjusting a potentiometer inside the unit while the bath is at the triple point maintenance temperature The bath temperature should be known to within 0 05 C A DVM capable of measuring accurately to 10mV is required To access
65. ion 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 unit Power to the bath passes through a filter to prevent switching spikes from being transmitted to other equipment To turn on the bath switch the control panel power switch to the ON position The stirring motor turns on the LED display begins to show the bath tempera ture and the heater turns on or off until the bath temperature reaches the pro grammed set point When powered on the control panel display briefly shows a four digit number This number indicates the number of times power has been applied to the bath Also briefly displayed is data which indicates the controller hardware configu ration 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 glows green when the heater is off The indicator pulses constantly when the bath is maintaining a sta ble temperature Temperature Controller Hart Scientific s unique hybrid
66. mn 62 10 Digital Communication Interface Power Control Functions 10 4 data denoted by n may be entered in decimal or exponential notation Char acters are shown in lower case although upper case may be used Spaces may be added within command strings and are simply ignored Backspace BS ASCII 8 may be used to erase the previous character A terminating CR is im plied with all commands Power Control Functions The digital interface is capable of controlling the cooling function so that the instrument can be remotely operate at any temperature within the range of the bath To allow the interface to control the cooling disable the front panel con trols by switching the refrigeration switch to OFF Otherwise the interface would not be able to switch these functions off To control the refrigeration power with the digital interface the front panel re frigeration switch must be off The refrigeration power function is controlled with the F2 command Setting the F2 value to O turns the refrigeration off and setting the F2 value to 1 turns the refrigeration on F2 alone returns 0 or 1 showing the state of the refrigeration power control as shown in the fol lowing table Function Command 0 1 Refrigeration F2 off on 63 11 Calibration Procedure Calibration Points 2 Point Calibration 11 11 1 11 2 11 3 Calibration Procedure In some instances the user may want t
67. n repeatedly until the display reaches PrObE Press the UP button repeatedly until the IEEE 488 interface menu is indicated with IEEE Press the SET button to enter the IEEE 488 parameter menu IEEE 488 Address The IEEE 488 address is prompted with AddrESS Press the SET button to program the address The default address is 22 If necessary change the device address of the bath to match the address used by the communication equip ment To change the device address press the UP or DOWN button and then the SET button Transmission Termination The IEEE 488 transmission termination is prompted with EOS Press the SET button to access the termination character The present setting is dis played Press the UP or DOWN button to change the setting Press the SET button to save the new selection IEEE 488 Operation Commands may now be sent via IEEE 488 interface to read or set the tempera ture or access other controller functions All commands are ASCII character strings and are terminated with a carriage return CR ASCII 13 Interface commands are listed below Interface Commands The various commands for accessing the bath controller functions via the digi tal interfaces are listed in this section see Table 4 These commands are used with both the RS 232 serial interface and the IEEE 488 GPIB interface In ei ther case the commands are terminated with a
68. n the cutout board the two test points TP1 and TP2 and attach the DVM In order to prevent the cutout from activating during adjustment it must be turned off in the controller menu To disable the low temperature cutout access the operating parameters menu Follow the instructions in Section 9 11 2 and set the triple point cutout tP CO to OFF toggling with either the up or down keys Set the water triple point cutout to 0 01 C With the bath controlling at 0 C to 0 01 C adjust VR1 on the board until the voltage reads O volts After the adjustment return the cutout to the ON condition and set the water triple point cutout set point to 0 3 C 69 12 Charging Instructions Leak Testing 12 12 1 12 2 12 3 Charging Instructions The 7312 uses R 134a with a polyolester oil Care must be taken to avoid con tamination from other types of refrigerants and oils Leak Testing Leak testing should be done with equipment designed for use with R 134a Bubble electronic halogen detector or ultra sonic leak testing may be viable in some instances Evacuation DO NOT leave the system open for more than 15 minutes Polyolester oils are very hygroscopic Evacuate the system to a minimum of 200 microns Evacuate from both high and low sides of the system Schrader valves provide access to the system Charging After evacuation charge the system with 160 grams of R 134a Set the suction pressure to 8 10 psig for operation
69. nal price Fluke reserves the right to invoice Buyer for importation costs of repair replacement parts when product purchased in one country is submitted for repair in another country Fluke s warranty obligation is limited at Fluke s option to refund of the purchase price free of charge repair or replacement of a defective product which is returned to a Fluke authorized service center within the warranty period To obtain warranty service contact your nearest Fluke authorized service center to obtain return authorization information then send the product to that service center with a description of the difficulty postage and insurance prepaid FOB Destination Fluke assumes no risk for damage in transit Following warranty repair the product will be returned to Buyer transportation prepaid FOB Destination If Fluke determines that failure was caused by neglect misuse contamination alteration accident or abnormal condition of operation or handling including overvoltage failures caused by use outside the product s specified rating or normal wear and tear of mechanical components Fluke will provide an estimate of 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 WA
70. nd after a delay cycle of about 2 minutes High and low voltage protection limits at 115 VAC Voltage Cutout 12 5 101 129 VAC Voltage Cutin 7 5 106 124 VAC High and low voltage protection limits at 230 VAC Voltage Cutout 12 5 203 257 VAC Voltage Cutin 7 5 213 247 VAC See the Caution in the front of this manual for additional information Testing the Line Voltage If the power line voltage is too low 90 of the compressor s rated voltage the compressor could be damaged Place a DVM in the supply line on the wall that feeds the bath Measure the line voltage under load with the bath on If the line voltage is low or marginal disconnect any other devices that are using the same line Alternately move the bath to a loca tion where the supply voltage is good If none of these are possible contact an electrician to re route the correct power If necessary you can inspect the oper ation of the line monitor by opening the electronics cover See the Caution at the front of this manual for a summary of the ICM491 operation Hart does not recommend adjustment of the operating voltage in order to use the instrument Instead an electrician should be consulted to alleviate the problem with the power source 75 7312 TPW Maintenance Bath User s Guide 76 Problem Causes and Solutions The heater indicator LED stays red but the temper ature does not increase If the display does not
71. ng 14 14 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 section carefully and attempt to understand and solve the problem If the probe seems faulty of the problem cannot otherwise be solved contact an Authorized Service Center see Section 1 3 for assistance Be sure to have the model number serial number and voltage of your instrument available Problem Causes and Solutions The bath does not turn Ifa fault condition exists upon application of power the bath will not energize on and the display re The bath needs to be plugged in to the line voltage for at least 2 minutes before mains blank turning power on This is only necessary for the first time that the bath is ener gized or when it is moved from one location to another If a high or low voltage condition exists for longer than 5 seconds the compres sor is de energized and the Mains Out of Range light on the back panel illumi nates indicating a fault condition Re energization is automatic upon correction of the fault condition a
72. nt Controller 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 the tempera tures 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 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 the EXIT button is pressed any changes made to the displayed value are 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 29 7312 TPW Maintenance Bath User s Guide 5 The cooling on off switch turns on the refrigeration for control below 50 C and rapid cool down 7 2 Bath Tank and Lid The bath tank and lid assembly includes the tank the c
73. o calibrate the bath to improve the tem perature set point accuracy Calibration is done by adjusting the controller probe calibration constants DO and DG 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 by carefully following the procedure the bath can be calibrated to an accuracy of better than 0 1 C over a range of 50 degrees Calibration Points 2 Point Calibration In calibrating the bath DO and DG 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 are obtained when using bath temperatures which are just within the most useful operating range of the bath The farther apart the calibration temperatures the larger the calibrated temperature range but the calibration error is also greater over the range For instance if 20 C and 80 C are chosen as the calibration tempera tures the bath may achieve an accuracy of say 0 2 C over the range 20 to 80 C Choosing 30 C and 70 C may allow the bath to have a better accuracy of maybe 0 05 C over the range 30 to 70 C but outside the range the accuracy may be only 0 5 C Measuring the Set point Error The first step in t
74. ociated 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 must be used if hazardous 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 of 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 ignites This does not necessarily mean that fire is 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 measured under the condition of vapors escaping the tank The closed cup flash point is measured with the vapors being contained within the tank Since oxygen and an ignition source is less available inside the tank the closed cup flash point is lower than the open cup flash point Environmentally hazardous fluids require special disposal according to applica ble federal or local laws after use 33 7312 TPW Maintenance Bath User s Guid
75. on the unit before the tank is filled with fluid Use the handles pro vided to move the unit Due to the weight of the compressor it may re quire two people to safely move the bath If two people are used place one person in the front and one person in the back of the unit carefully slide hands under the unit and lift in unison The area containing the com pressor will be heavier than the rest of the unit Do not move a unit filled with fluid 1 Before You Start Authorized Service Centers 1 3 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 that the bath is energized or when it is moved from one location to another Turning the bath ON or OFF does not trigg
76. ons e eae 57 10 1 1 WIDE PC ae E RED A A ee Oe eee 57 10 1 2 SOUP an ra a aa ra da 58 10 21 BAUD Rate A uu o hom om 9o ose ia a De ais a isa dle s 58 10 1 222 Sample Period o uo he doe id E ae eR aa Se dl di Ge BE 59 103 2 3 Duplex M d 44 wos Mee he See eat ais e A a 59 10 1 2 4 Linefeed ce i Soe a ww ee eee tes oes ld tes Sin ae tacts ee des Ro m ed hs Rede Rom We wy A 59 10 1 3 Setial Operation 23 Lg ee Rug ee 4 HHS EE Deed Ss SLE 5 59 IEEE 488 Communication optional 39 10 2 1 Sep awe oe A Y EER SG Es s 60 10 2 1 1 IBEE 488 AddteSS sorda p RR ed Rye RAE SEES 60 10 2 1 2 Transmission Termination llle 60 10 2 2 TEEE 488 Operation eA 60 Interface Commands ees 60 Power Control Functions 0000000004 63 11 Calibration Procedure 65 11 1 11 2 11 3 11 4 11 5 11 6 Calibration Points 2 Point Calibration 65 Measuring the Set point Error so o oos 65 Computing DO and DG rober caras xU ex 65 Calibration Example dw xou e a OM 66 Single Point Calibration dci Da ee 39e o3 9 9x a 66 Measuring the Set point Error x se sz Rs 67 iii ii Computing D lt se odo m Ie RE Narda AA 68 11 8 Calibrating the Triple Point of WaterCutout 68 12 Charging Instructions o o 71 12 1 Leak los 2a 9x4 3 RW OE a A S xU 71 12 2 Eya c ation o se ba a 399430 99
77. ontrol probe the stir ring motor the access hole and the access hole cover The stirring motor cover covers the stirring motor cooling fan control probe and triple point of water cutout probe 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 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 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 The triple point of water cutout probe senses bath temperature and acti vates the low temperature cutout to turn off the refrigeration below a pre set temperature in case of temperature controller failure This feature is intended to protect triple point of water cells 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 The large access hole on the bath lid is used for filling and emptying the bath with fluids and for placement of thermometers TPW cells and other devices into the bath An access hole cover should be used to cover the access opening in the top of th
78. or reading the MSDS material safety data sheets and acting accordingly About the Graph The fluid graph visually illustrates some of the important qualities of the fluids shown 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 Fume Point The point at which a fume hood should be used This point is very subjective in nature and is impacted by individual tolerance to different fumes and smells how well the bath is covered the surface area of the fluid in the bath the size and ventilation of the facility where the bath is located and 35 7312 TPW Maintenance Bath User s Guide Table 2 Table of Various Bath Fluids and Their Properties Lower Upper Thermal Thermal Fluid Temperature Temperature Flash Viscosity Specific Specific Heat Conductivity Expansion Resistivity Hart Part No Limit Limit Point centistokes Gravity cal g C cal s cm C cm cm C 10 0 cm Halocarbon 0 8 100 C v 70 C e NONE 5 7 50 C 1 71 0 40 C 0 2 0 0004 0 0011 5019 0 8 40 C 0 5 70 C Methanol
79. own in Figure 4 6 Bath Use Triple Point of Water Cell Maintenance Rubber Shock Guides Thermometer Precooling Holes Access Cover Removable Guide Tubes Adapter Guide Location Top Plate Adjusting Set Screws Support Rods TPW Cells Baffle l Rubber r Grommet Bottom Plate f Guide Location Figure 2 Details of the Access Cover and Cell Racks 23 7312 TPW Maintenance Bath User s Guide 24 6 2 5 6 2 6 Adjusting the fluid level so that the top bell is exposed permits added heat input to the cell causing the top of the ice mantle to melt Careful adjustment can ad equately maintain the cell while reducing the ice bridging at the top of the cell The fluid and fluid level should be regularly checked If a second cell is added or removed for a prolonged period adjust the fluid level appropriately Keep the fluid clean Verify that there is no ice formation on the sides in the lower half of the tank Formation of ice indicates insufficient alcohol in the water Features of the Bath Access Cover The bath access cover fits over the opening of the bath providing a barrier against the ambient temperature while providing holes for immersion of ther mometers Remove the cover to maintain the cells and bath fluid Normally the cover must be on See Figure 2 The four wells toward the rear of the cover are used for pre cooling thermome ters of typical SPRT size and smaller diameter Pre cool each thermom
80. proper and safe operation of the bath These parameters should not be adjusted except in the event the controller s memory fails The user may then restore these values to the factory settings A list of these constants and their settings are supplied to the user on the Report of Test with the manual CAUTION DO NOT change the values of the bath calibration constants from the factory set values The correct setting of these parameters is im portant to the safety and proper operation of the bath The calibration parameters menu is indicated by CAL Calibration parameters menu Press the SET button five times to enter the menu CTO Parameter CTO sets the calibration of the over temperature cutout This param eter is not adjustable by software but is adjusted with an internal potentiometer For the 7312 bath this parameter should read 160 H and L These parameters set the upper and lower set point limits of the bath DO NOT change the values of these parameters from the factory set values To do so may 55 7312 TPW Maintenance Bath User s Guide present danger of the bath exceeding its temperature range causing damage or fire 56 10 Digital Communication Interface Serial Communications 10 10 1 10 1 1 Digital Communication Interface The 7312 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 R
81. re Likewise if the ice mantle seems to be melting back lower the temperature Adjusting the TPW Cell Rack The 7312 bath is provided with two adjustable racks that provide stable loca tion for the cells See Figure 2 Remove the racks by reaching in and withdraw ing them The stainless steel baffles on the left and right sides of the tank act as guides or tracks to locate and retain each rack A TPW rack consists of support rods a bottom plate and a top plate The support plates are positioned on the support rods with set screws Each plate is individually adjusted in order to ad just cell depth and to adjust cell fit Start by adjusting the bottom plates until the cell is at the proper height Rubber grommets protect the cell surfaces from direct contact with the metal The top plate is sufficiently large for the Hart Sci entific Model 5901 cell Adapters are provided for each rack to fit the Hart TPW cells and most other commercially available cells Other adapters are available upon request Fluid Level The bath fluid level may be adjusted as desired for the cells Typically the fluid level for the Hart Scientific Model 5901 cell is below the funnel but above the top end bell of the cell The Hart Scientific Model 5901A cell fluid level may be just under or just over the opening Use the adjustability of the racks to com pensate for different cell designs See the Figure 3 The handles of the NBS style cells Hart Model 5901A are as sh
82. s 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 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 of the high temperature fluids react violently to water or other liquid mediums Be aware that cleaning the probe can be danger ous if the probe has not cooled to room temperature Additionally high temper ature fluids may ignite the paper towels if the probe has not been cooled For optimum accuracy and stability allow the bath adequate stabilization time after reaching the set point temperature Triple Point of Water Cell Maintenance Bath Preparation The bath fluid to maintain the TPW cell must be able to operate near 0 C with out freezing Water alone can freeze Water with about 10 ethanol is a good fluid for this application It retains most of the excellent temperature control prop
83. s over a wide temperature range from 5 C to 110 C The refrigeration permits sub ambient temperature control 3 Specifications and Environment Conditions Specifications 3 1 3 2 Specifications and Environment Conditions Specifications Range 5 C to 110 C Stability 0 001 C at 0 C alcohol water mix 0 004 C at 30 C alcohol water mix Uniformity 0 003 C at 0 C alcohol water mix 0 006 C at 30 C alcohol water mix TPW Duration Six weeks typical assumes correctly formed ice mantle Set Point Accuracy 0 05 C at 0 C Set Point Repeatability 0 01 C Display Resolution 0 01 C Set Point Resolution 0 002 C 0 00003 C in high resolution mode Access Opening 4 75 x 3 8 121 x 97 mm Immersion Depth 19 5 496 mm Volume 5 gallons 19 liters Power 115 VAC 10 60 Hz or 230 VAC 410 50 Hz Size 12 W x 24 5 W x 32 25 H 305 x 622 x 819 mm Weight 75 lb 34 kg Automation Package Interface it software and an RS 232 computer interface are available for setting the bath temperature via an external computer For IEEE 488 add 2001 IEEE to the automation package Safety OVERVOLTAGE Installation CATEGORY II Pollution Degree 2 per IEC1010 1 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
84. 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 73 7312 TPW Maintenance Bath User s Guide 74 If the mains supply cord becomes damaged replace it with a cord with the appropriate gauge wire for the current of the bath If there are any questions call an Authorized Service Center 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 to be sure that the proposed method does 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 1t is working properly In order to check the user selected cutout follow the controller directions Section 10 2 for setting the cutout 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 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 14 Troubleshooting Troubleshooti
85. selection Set point 1 25 0 C currently used Press the SET button to select this memory and access the set point value SET Access set point value C 25 80 l Current value of set point 1 25 00 C rana Press the UP or DOWN button to change the set point value 4 Quick Start Setting the Temperature Increment display E 30 00 New set point value Press the SET button to accept the new value and to display the vernier value The bath begins heating or cooling to the new set point SET Store new set point access vernier 0 00000 Current vernier value Press the EXIT button and the bath temperature is displayed again exa Return to the temperature display 24 13 E 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 8 Cutout To obtain optimum control stability adjust the proportional band as discussed in Section 9 7 Proportional Band 15 5 Installation Bath Environment 5 5 1 5 2 5 3 5 3 1 Installation A CAUTION Read Section 6 entitled BATH USE before placing the bath into service Bath Environment The Model 7312 Bath is a precision instrument which sho
86. set point for exam ple 0 008 C for the triple point of water cell maintenance Verify that the ver nier is set at 0 Wait for the bath to reach that temperature and allow 30 minutes for the bath to stabilize at that temperature Check the bath stability with the thermometer When both the bath and the thermometer have stabilized measure the bath temperature with the thermometer and compute the temperature error which is the set point temperature minus the actual bath temperature Error T T p actual 67 7312 TPW Maintenance Bath User s Guide Example Actual temperature 0 132 C Set point temperature 0 008 C error 0 008 0 132 0 124 including sign 11 7 Computing DO 68 11 8 Before computing the new values for DO the current value must be known The value 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 this value in case it may need to be restored in the future The new value DO is computed by subtracting the temperature error from the old value for DO as follows DO DO error Example Old DO 25 438 error 0 124 C DO 25 438 0 224 25 662 Enter the new DO value into the controller and press the SET button Wait for the temperature to stabilize and measure the temperature again If desired the calibration procedure may be repeated to further
87. show cutout and shows the correct bath temperature consider the following possibilities No heating This is caused by blown heater fuses and or burned out heaters Check the heater fuses to make sure that they are still good Access the heater fuses by removing the front panel under the display electronics If they are blown and continue to blow when replaced the heaters may be shorted If you suspect that the heaters are shorted or burned out contact an Authorized Ser vice for assistance The controller display flashes CUTOUT and the heater does not operate If the display flashes cut out alternately with the correct process temperature check the following Wrong cutout setting The cutout disconnects power to the heaters when the bath temperature exceeds the cutout set point This causes the bath tempera ture 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 If the mode is set to RE SET the heater only comes on again when the temperature is reduced and when the cutout is manually reset by the operator Refer to Section 10 8 Check that the cutout set point is adjusted to 10 or 20 C above the desired maximum bath operating temperature and that the cutout mode is set as desired Continuous cutout If the cutout activates when the bath temperature is well below the cutout set point or the cutout does not reset when the bat
88. ss the UP or DOWN buttons Decrement display To accept the new setting and access the cutout set point press the SET but ton Pressing the EXIT button exits the secondary menu ignoring any changes just made to the proportional band value SET Accept the new proportional band setting 9 Controller Operation Cutout 9 8 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 temperatures 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 the power to the heater is shut off and the bath cools 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
89. ssembly 17 7312 TPW Maintenance Bath User s Guide 18 5 3 2 Ensure the valve handle is in the closed position before attempting to add fluid to the tank 1 Je di ba Figure 1 Drain Valve Installation IMPORTANT Do Not Over Tighten Follow the installation instructions above Filling With Fluid The Model 7312 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 Fluids are discussed in detail in Section 9 1 Heat Transfer Fluid Remove any access hole cover from the bath and check the tank for foreign matter dirt remnant packing materials etc Fill the bath with clean unpolluted fluid Fill the bath carefully through the large rectangular access hole to a level that allows for stirring and thermal ex pansion Section 9 1 5 Thermal Expansion explains fluid expansion DO NOT turn on the bath without fluid in the tank Maximum and minimum fill levels are dependent on the application whether it is used for TPW cells or compari son calibration Carefully monitor the bath fluid level as the bath temperature rises to prevent overflow or splashing Remove excess hot fluid if necessary with caution 5 Installation Power 5 4 Power With the bath power switch off plug th
90. t 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 9 General Operation for more information about the different types of fluids used in calibration baths e Depending on the cleanliness of the environment the internal parts parts behind the front cover only of the cold bath should be cleaned and or checked at least every month for dust and dirt Particular attention should be paid to the condensing coil fins The fins should be vacuumed or brushed free of dust and dirt on a regular basis Dust and dirt inhibit the operation of the condensing coil and thus compromise the performance and lifetime of the cooling system e Ifa hazardous material is split on or inside the equipment the user is re sponsible for taking the appropriate decontamination steps as outlined by the national
91. te of the bath may be programmed to 300 600 1200 or 2400 BAUD The BAUD rate is pre programmed to 2400 BAUD Use UP or DOWN to change the BAUD rate value Press the SET button to set the BAUD to the new value or the EXIT button to abort the operation and skip to the next pa rameter in the menu Sample Period The sample period is the next parameter in the menu and prompted with SAMPLE The sample period is the time period in seconds between temper ature measurements transmitted from the serial interface If the sample rate is set to 5 the bath transmits the current measurement over the serial interface ap proximately every five seconds The automatic sampling is disabled with a sample period of 0 Press the SET button to choose to set the sample period Adjust the period with the UP or DOWN button and then use the SET to set the sample rate to the displayed value Duplex Mode The next parameter is the duplex mode indicated with dUPL 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 immedi ately echoed or transmitted back to the device of origin With half duplex the commands are executed but not echoed The default setting is full duplex The mode may be changed using UP or DOWN and pressing SET Linefeed The final parameter in the serial inter
92. temperature controller set point is too low or if the heater fails When the TPW cutout is triggered the display alternately flashes tP cto and the current bath temperature The serial port outputs TPW Cutout every three seconds Pressing any button causes the cutout error mes sage to stop being output until another TPW cutout error has occurred Each time the cutout is tripped the bath temperature set point automatically in creases in 0 5 C increments until the set point has reached a maximum of 25 C The parameter is indicated by 51 7312 TPW Maintenance Bath User s Guide 52 9 12 9 12 1 EP CO Triple point of water cutout parameter rra Press the SET button to access the activation selection Press the UP or DOWN button to turn the cutout on or off and then press the SET button Normally the cutout is ON Press the EXIT button to return to the operating parameters menu ranma E 0 30 Cutout temperature in degrees C or F ranma To change the cutout temperature use the UP or DOWN button To accept the new cutout set point press the SET button Press the EXIT button to return to the operating parameters menu Serial Interface Parameters The serial RS 232 interface parameters menu is indicated by SEFIAL Serial RS 232 interface parameters menu The serial interface parameters menu contains parameters which determine the operation of the s
93. the bath for many weeks if the daily maintenance is properly kept up The daily maintenance consists of the following 6 Bath Use Triple Point of Water Cell Maintenance Fluid Level in Bath o ww EJ aM i ELS Figure 3 Fluid Level 25 7312 TPW Maintenance Bath User s Guide Figure 4 Location of Handles for NBS Design Cells e Check for ice bridging every 1 to 3 days as required Ice bridging is ice forming at the top surface of the water in the cell that bridges from the reentrant tube to the outer glass wall Ice bridging can cause a cell to be broken It must be melted back regularly CAUTION Wipe bath fluid off the cell as it is removed to prevent fluid from running onto the bath controller e Check the ice mantle to see if it is free from the reentrant tube perhaps several times a day depending upon use This freedom of movement means that there is a thin layer of water all around the reentrant tube If it 1s not free to move small errors result in the acquired temperature Insert a room temperature rod into the fluid in the reentrant tube transferring heat to the ice until the mantle moves freely This movement can be checked by rotating the cell quickly around its long axis The ice tends to stay in place as the cell rotates if it is free e Make fine adjustments as needed to the bath set point temperature to in sure that the cell mantle is neither freezing nor m
94. trol probe Check that the control probe has not been struck bent or damaged Refer to the previous solution for how to check the probe s resistance The controller shows that it is controlling at the proper temperature but the bath temperature is unstable If the bath does not achieve the expected degree of temperature stability when measured using a thermometer consider the following Wrong proportional band setting If the proportional band is set too narrow the bath will oscillate causing poor stability In this case increase the width of the proportional band If the proportional band setting is too wide the long term stability of the bath is affected In this case decrease the width of the band Refer to Section 9 7 Bath fluid is too thick Make sure that the bath fluid used is less than 50 centi Stokes 10 is ideal at the temperature at which the bath is controlling Check the fluid manufacturer s specifications You should also change the bath fluid regularly and if it changes colors or be comes too thick Defective control probe Check that the control probe has not been struck bent or damaged Refer to the previous solution for how to check the probe s resistance The controller alternately heats for a while then cools Wrong proportional band setting If the proportional band is set too narrow the bath will oscillate between too much heating and too much cooling causing instability Increase th
95. u 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 Ns AC Alternating Current ING AC DC Battery AA MAN CE Complies with European Union Directives DC Double Insulated Electric Shock Fuse PE Ground Hot Surface Burn Hazard Read the User s Manual Important Information Off On OPPOIPOHO 7312 TPW Maintenance Bath User s Guide Symbol Description Canadian Standards Association Cc us OVERVOLTAGE Installation CATEGORY II Pollution Degree 2 per IEC1010 1 re CATE 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 C TIC Australian EMC Mark 2002 96 EC mark 1 2 Safety Information Use this instrument only as specified in this manual Otherwise the protection provided by the instrument may be impaired 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
96. uld 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 Allow plenty of space around the bath for 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 should be used to remove any vapors given off by hot bath fluid Dry out Period Before initial use after transport and any time the instrument has not been en ergized for more than 10 days the bath needs to be energized for a dry out period of 1 2 hours before it can be assumed to meet all of the safety require ments of the IEC 1010 1 Bath Preparation and Filling CAUTION Before filling the tank with fluid the drain valve must be in stalled onto the pipe fitting at the back of the bath Drain Valve Installation Instructions The drain valve attaches to the swage fitting located on the lower backside of the bath See Figure 1 1 Place the valve onto the drain fitting and hand tighten in place by turning the hex nut attached to the bath counter clockwise while holding the valve stationary 2 Using open end wrenches hold the valve in place and tighten the hex nub one quarter turn from the hand tightened position above The valve should be secured in place at this point If not repeat step number 2 being careful not to over tighten the a

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