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1. To set the temperature one must first select the set point memory This function is accessed from the temperature display function by pressing SET The number of the set point memory currently being used is shown at the left on the display followed by the current set point value 9 1 7102 User s Guide Displ ay Tempera e E aw Adust Setpoint Units CAF Secondar y Functions Display Power Ad ALPHA TAYA 335 SST SSSHL SONVHO LON OG Menu Legend Pres 5 SET to step through the menu and to store the parameter value Pres 5 EXIT briefly to skip a parameter without star ingtheparameter value DO NOT CHANGE THESE VALUES SEE MANUAL Hold EXIT toe xtthe menu and dispa y ihetemperatur amp Figure 7 Controller Operation Flowchart 9 2 Controller Operation 9 2 Temperature Set point 100 00C Well temperature in degrees Celsius BEE l J Access set point memory Press SET to accept the new selection and access the set point value SET Accept selected set point memory 9 2 2 Set point Value The set point value may be adjusted after selecting the set point memory and pressing SET 4125 Set point 4 value in C If the set point value is correct hold EXIT to resume displaying the well temperature Press UP or DOWN to adjust the set point value 125 00 New set point value When the desired set point value is reached pr
2. 25 C 0 66 OG 0 792 20 C 0 45 20 C Water orc fr 95 C b NONE 18250 1 00 100 0 0014 0 0002 25 C 0 4 75 C Ethylane 35 C fr HOL ib NONE 7 0C 1 05 0 8 ee 0 001 Glycol 50 2 50 C 3020 0 7 amp 100 C Mineral Oil 40 C v 190 C fl 190 C 15 75 C 087 256 048 AE 0 00025 25 C 0 0007 50 C 5 amp 25 C 5 125 C 0 84 75 0 53 75 C 0 81 amp 125 C 0 57 125 C Dow Coming 40 C v 133 C DL cc 199 C 5 25 0 92 25 C 0 4 0 00028 25 C 0 00105 1000 25 C 200 05 Silicone 10 150 C Oil Dow Coming 35 C v 165 C fl cc 166 C 10 25 C 0 934 25 C 0 43 amp 40C 0 00032 25 C 0 00108 1000 25 C 200 10 45012 3 125 C 0 45 100 C 50 150 C 0 482 200 C Dow Corning 7 C v 230 C cc 230 C 20 25 C 0 949 25 G 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 Dow Corning 25 C v 280 C fl ce 280 C 50 25 C 096 8 256 04 0 00037 25 C 0 00104 1000 25 C 200 50 Silicone 50 150 C Oil Dow Corning on v 232G fl ce 232 C 50 70C 107 25 C 0 358 40 C 0 00035 25 C 0 00075 100 25 C 550 300 G fl oc 10 104 C 0 386 100 C 1 150 C der 0 433 200 C Dow Corning BOG v 302 C fl oc 302 C 50 BOG 111 25 C 0 363 40 C 0 00035 25 C 0 00077 100 25 C 710 7 204 C 0 454 amp 100 C 1 150 C HSD 7 0 505 200 C Dow Coming 66 C v 315 C fl oc 315 C 50 66
3. Never introduce any foreign material into the well 11 2 Stabilization and Accuracy The stabilization time of the Micro Bath depends on the conditions and temperatures involved Typically the test well will be stable to 0 1 C within 10 minutes of reaching the set point temperature Ultimate stability will be achieved 30 minutes after reaching the set temperature Inserting a cold probe into a well requires another period of stabilizing depending on the magnitude of the disturbance and the required accuracy For example inserting a 25 inch diameter room temperature probe at 200 C takes 5 minutes to be within 0 1 C of its settled point and takes 10 minutes to achieve maximum stability Speeding up the calibration process can be accomplished by knowing how soon to make the measurement Typical measurements should be made at the desired temperatures with the desired test probes to establish these times Chapter 12 Calibration Procedure Note This procedure is to be considered a general guideline Each laboratory should write their own procedure based on their equipment and their quality program Each procedure should be accompanied by an uncertainty analysis also based on the laboratory s equipment and environment Sometimes the user may want to calibrate the bath to improve the temperature set point accuracy Calibration is done by adjusting the controller probe calibration constants RO ALPHA and DELTA so that the temperature
4. The LED front panel continuously shows the current well temperature The temperature may be easily set with the control buttons to any desired temperature within the specified range The calibrator s multiple fault protection devices insure user and instrument safety and protection The 7102 Micro Bath was designed for portability low cost and ease of operation Through proper use the instrument will continuously provide accurate calibration of temperature sensors and devices The user should be familiar with the safety guidelines and operating procedures of the calibrator as described in the instruction manual 2 1 7102 User s Guide 2 2 Chapter 3 Specifications and Environmental 3 1 Specifications Range Accuracy Stability Uniformity Resolution Operating Temperature Heating Time Cooling Time Exterior Dimension Readout Controller Thermal Electric Devices TED Cooling Fault Protection Safety Fuse Rating Conditions Table 2 Specifications 5 to 125 C 23 to 257 F 0 25 C 0 015 C at 5 C oil 5010 0 03 C at 121 C oil 5010 0 02 C 0 01 C F 5 to 45 C 41 to 113 F 25 C to 100 C 77 F to 212 F 30 minutes 25 C to 0 C 77 F to 32 F 30 minutes 2 5 dia x 5 5 deep 64 x 139 mm access opening is 1 9 48 mm in diameter 1 2 H x 7 2 W x 9 5 D 31 cm x 18 cm x 24 cm 15 Ib 6 8 kg with fluid 115 VAC 410 1 8 A o
5. 9 8 2 Serial Interface Parameters ee ee ee ee ee ee ee ee 9 9 9 8 2 1 Baud ER A eege ee 9 8 2 2 Sample benod ER ER Ee RE EER Ee ee ee ee ee ee ee ee ed 9 8 2 3 DUPIEX MOGGE se Ee ek ee oe oo 9 8 2 4 Linefeed EE ee ee ee ee ee ee ee ee ee ed 9 8 3 Calibration Parameters ee ee ee ee ee ee ee ee ee ee ee ee 96 35 DELMM E EO 110 OE EE NN EE EO EE N EE OE GN 10 Digital Communication Interface sees EER ER EE ER RE EE Re ER Re EE Re Re 10 1 Serial Communications ee ee ee ee ee ee ee ee ee ee ee ee ee eed VETT VG EE EE EE EE EO EEE E E EERE EAEE E 10 1 2 SUN 10 1 2 1 Baud BE CG 10 1 22 Sample Periode ii en Ee ie ee ie Gn 10 1 2 3 Duplex Mode ee ee ee Ee ee ee EE ER Ee Ee ee ee Ee ee ee ee d 124 50 ENEE 10 1 3 Serial Operaton ees ee ER Ee Re Re Re Re Ee Ee RE ee RE ee ee 10 2 Interface Commands EG 11 Test Probe Calibration a arunvavnvnnnnnavnvnnnnvnvnnunvavnvnnnnvnvnvunvnvnvnnunvnvnnnnnan 11 1 Calibrating a Single Drobe iese ss se ee Ee Ee RE ee Ee ee EE ee Ee ee EE ee ee ee 11 2 Stabilization and Accuracy ese ee ee ee ee ee Ee ee ee ee ee ee ee ee 12 Calibration Procedure arun aranunnanannnunnnvnvununvavnnnnunvnvnnunvavnvnnnnvnvnnnnvavnnnr VINN Gen EC 12 2 Calibration Procedure ee ee ee 12 2 1 EDEL NN 12 2 2 Compute RO amp Al DHA 12 2 3 Accuracy amp Repeatability 13 VE ah dn E ae EEN 14 TFOUDICSNOOUING E 14 1 Troubleshooting Problems Possible Causes and Solutions
6. 14 2 COMMENS EE 14 2 1 EMC DEN een 14 2 2 Low Voltage Directive Safety es ee EE ee Ee RE ee EE ee il 7102 User s Guide List of Tables Table Title 1 International Electrical Symbols ccc cceccceeccceeeceeeeceeeeeeeeseeeeeeeeaeeeeaees 2 ele IU ONS AE EN EN 3 Table of Various Bath Fluids iese see ee ee ee ee EE ee EE ee ee Re ee ee ee ee 4 Nominal Stirrer Motor SettingsWith Different Liquids D Controller Communications Commande 7102 User s Guide vi List of Figures Figure 1 FFF CT 2 7102 Back Panel and Bottom ee ee ee ee ee E Bath Lids and Lid Parts EN 4 Probe Ba EE 5 VET 6 Chart of Various Bath FIuids ronnnnnnnnnnnnnnnnnnnrnnnnnnrnrnvnennnenenenenananennenenenen T Controller Operation Flowchart 8 Serial Cable Wung ee ee Ee Ee EE ER EE ee Ee RE ee ee RE Ee ee Ee ee ee ee ee RE ee Vil 7102 User s Guide viii Chapter 1 Before You Start 1 1 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 fee fo 0 GH Veme A lees Es OSC lees Ise A Read users Ge pontoon oe 1 fm OVERVOLTAGE Installation CATEGORY II Pollution Degree 2 per IEC1010 1 refers to the level of Impulse Withstand Voltage protection provided Equipment of OVERVOLTAGE CATEGORY II is
7. C 0 96 25 C 0 34 100 C 0 0003 0 00095 100 25 C 210 H Silicone 14 204 C 1 150 C Oil Heat Transfer 9 145 C fr 530 C NONE 34 150C 2 0 150 C 0 33 0 0014 0 00044 17 ems Salt 45001 65 300 C 19 300 C 24 500 C 17 500 C Limiting Factors b boiling point o high evaporation fl flash point fr freeze point v viscosity Flash point test oc open cup cc closed cup Very low water solubility ica will form as a slush from condensation below freezing 8 5 7102 User s Guide 8 6 raw ile o Silicane Oil 5012 p Silicone OM HFE 7500 de Halocarbon 5019 1005 N 5011 1068 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 G Seegen Point wig Black area represents liquid range with excessive viscosity FR Freeze Point Range over which a fume hood is recommended Figure 6 Chart of Various Bath Fluids 8 3 11 2 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 fluids general range of application is indicated by the shaded bands Qualities including pour point freeze point important viscosity points flash point boiling point and others may be shown Freezing Point
8. The freezing point of a fluid is an obvious limitation to stirring As the freezing point is approached high viscosity may also limit performance General EE n 8 4 Stirring Pour Point This represents a handling limit for the fluid Viscosity Points shown are at 50 and 10 centistokes viscosity When viscosity is greater than 50 centistokes stirring is very poor and the fluid is unsatisfactory for bath applications Optimum stirring generally occurs at 10 centistokes and below Fume Point 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 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 8 3 8 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 Decomposition The temperature may reach a point at which decomposition of the fluid begins Further increasing the temperature may accelerate decomposition to the point of dan
9. be danger to people 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 equipment Fluids may be flammable and require special fire safety equipment and procedures 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 sufficient oxygen present and an ignition source is applied the vapor will ignite This does not necessarily mean that fire will be sustained at the flash point The flash point may be either of the open cup or closed cup type Either condition may occur in a bath situation The closed cup temperature is always the lower of the two The closed cup represents the contained vapors inside the tank and the open cup represents the vapors escaping the tank Oxygen and an ignition source will be less available inside the tank Environmentally hazardous fluids require special disposal according to applicable federal or local laws after use 8 3 9 Cost Cost of bath fluids may vary greatly from cents per gallon for water to hundreds of dollars per gallon for synthetic oils Cost may be an important cons
10. in decimal or exponential notation Characters are shown in lower case although upper case may be used Spaces may be added within command strings and will simply be ignored Backspace BS ASCII 8 may be used to erase the previous character A terminating CR is implied with all commands Table 5 Controller Communications Commands Command Description Command Format Command Example Returned Returned Example Acceptable Values Display Temperature Read current set point s etpoint s set 999 99 IC or F set 150 00 C Set current set point to n s etpoint n s 200 00 Instrument Range Read temperature tlemperature t t 999 99 IC or F t 55 6 C Read temperature units uinits u us x u C Set temperature units u nits c f CorF Set temperature units to Celsius ufnits c U C Set temperature units to uinitsl f u f Fahrenheit Read scan mode sclan SC scan ON or OFF scan ON Set scan mode sclan on off sc on ON or OFF Read scan rate striate st srat 99 9 C or Fi min srat 12 4C min Set scan rate sriatel n st 1 1 1 to 99 9 Read hold holld ho hold open closed hold open 30 5 C 99 9 IC or F Secondary Menu Read proportional band setting priopband pr pb 999 9 pb 15 9 Set proportional band to n priopbandl n pr 8 83 Depends on Configuration Read heater power po wer po po 999 9 po 1 0 duty cycle Configuration Menu Operating Parameters Menu Read stirrer motor speed moltor mo mo 99 mo 15 Set stirrer motor speed to n mo torj n mo 16 0 t
11. less than 25 C 77 F and the unit has been drained or the Transport Lid installed BURN HAZARD ALWAYS ensure the instrument is COOL before closing the instrument for storage DO NOT touch the well access surface of the unit DO NOT mix water and oil when exceeding temperatures of 90 C 194 F DO NOT mix water and oil when exceeding temperatures of 90 C 194 F The temperature of the well access is the same as the actual temperature shown on the display e g if the unit is set at 125 C and the display reads 125 C the well is at 125 C Ensure the power cord is positioned in such a way as it cannot contact hot surfaces or temperature probes Always inspect power cord before use for any damage to the insulation due to contact with hot surfaces cuts or abrasions The top sheet metal of the instrument may exhibit extreme temperatures for areas close to the well access DO NOT turn off the unit at temperatures higher than 100 C This could create a hazardous situation Select a set point less than 100 C and allow the unit to cool before turning it off DO NOT remove the fluid at high temperatures The fluid will be the same temperature as the display temperature DO NOT operate near flammable materials Extreme temperatures could ignite the flammable material Use of this instrument at HIGH TEMPERATURES for extended periods of time requires caution 1 3 7102 User s Guide ELECTRICAL HAZARD
12. main menu after the scan control function The scan rate units are in degrees C per minute Sr 10 0 l Scan rate in C min Press SET to accept the new scan rate and continue E SET Accept scan rate 9 4 Temperature Display Hold The 7102 has a display hold function which allows action of an external switch to freeze the displayed temperature and stop the set point from scanning This is useful for testing thermal switches and cut outs The instrument must be powered off before attaching thermal switches or cut outs This section explains the functions available for operating the temperature hold feature An example follows showing how to set up and use the hold feature to test a switch Controller Operation 9 4 Temperature Display Hold 9 4 1 Hold Temperature Display The hold feature is enabled by simply pressing the UP button when the temperature is displayed The hold temperature display shows the hold temperature on the right and the switch status on the left For the status c means the switch is closed and o means the switch is open The status flashes when the switch is in its active position opposite the normal position The hold temperature shows what the temperature of the well was when the switch changed from its normal position to its active position While the switch is in the normal position the hold temperature will follow the well temperature If the Scan Control is OFF and the Hold Te
13. of the bath as measured with a standard thermometer agrees more closely with the set point The thermometer used must be able to measure the well temperature with higher accuracy than the desired accuracy of the bath By using a good thermometer and following this procedure the bath can be calibrated to an accuracy of better than 0 5 C up to 200 C 12 1 Calibration Points In calibrating the bath RO ALPHA and DELTA are to minimize the set point error at each of three different bath temperatures Any three reasonably separated temperatures may be used for the calibration Improved results can be obtained for shorter ranges when using temperatures that are just within the most useful operating range of the Micro Bath The farther apart the calibration temperatures the larger will be the calibrated temperature range but the calibration error will also be greater over the range If for instance 50 C to 150 C is chosen as the calibration range then the calibrator may achieve an accuracy of say 0 3 C over the range 50 to 150 C Choosing a range of 50 C to 90 C may allow the calibrator to have a better accuracy of maybe 0 2 C over that range but outside that range the accuracy may be only 1 5 C 12 1 7102 User s Guide 12 2 12 2 Calibration Procedure 1 Choose three set points to use in the calibration of the RO ALPHA and DELTA parameters These set points are generally 40 0 C 95 C and 195 0 C but other set
14. parameters Controller Operation Q 9 8 Controller Configuration 9 8 1 1 High Limit The High Limit Parameter adjusts the upper set point temperature The factory default and maximum temperature are set to 126 C For safety a user can adjust the HL down so the maximum temperature set point is restricted HL High Limit parameter H 90 New HL setting Press SET to accept the new temperature limit 9 8 1 2 Stir Speed The Stir Speed parameter adjusts stirrer motor speed The factory default is 20 16 l New Stir Speed setting Press SET to accept the new Stir Speed The stir motor speed needs to be varied for best stability Table 3 on page 25 shows nominal settings for several fluids Serial Interface Parameters The serial RS 232 interface parameters menu is indicated by SErlAL Serial RS 232 interface parameters menu The serial interface parameters menu contains parameters which determine the operation of the serial interface These controls only apply to instruments fitted with the serial interface The parameters in the menu are baud rate sample period duplex mode and linefeed Press UP to enter the menu 9 9 7102 User s Guide 9 8 2 1 Baud Rate The baud rate is the first parameter in the menu The baud rate setting determines the serial communications transmission rate The baud rate parameter is indicated by TTT da bAUd Flashes bAUd and then displays
15. point When powered on the control panel display will briefly show 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 configuration This data is used in some circumstances for diagnostic purposes 8 6 Thermal Electric Devices TED The power to the bath is precisely controlled by the temperature controller to maintain a constant bath temperature Power is controlled by periodically switching the TEDs on for a certain amount of time using power transistors 8 8 General OperationgQ 8 7 Fluid Drain 8 7 Fluid Drain The fluid may be drained from the 7102 by tightly screwing the transport pour access lid onto the top of the bath and pouring the liquid into an appropriate container 8 8 Temperature Controller The bath temperature is controlled by Hart Scientific s unique hybrid digital analog temperature controller The controller offers the tight control Stability of an analog 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 control probe The signal is electronically compared with the programmable reference signal amplified and then fed to a pulse width modulator circuit which controls the amount of power applied to the bath heater The bath is operable within the temperature range given in the
16. points may be used if desired or necessary 2 Set the bath to the low set point When the bath reaches the set point and the display is stable wait 15 minutes or so and then take a reading from the thermometer Sample the set point resistance by holding down the SET key and pressing the DOWN key Write these values down as T1 and Ri respectively 3 Repeat step 2 for the other two set points recording them as To Ro Ts and R respectively 4 Using the recorded data calculate new values for RO ALPHA and DELTA parameters using the equations given below 12 2 1 Compute DELTA A T3 T2 B T2 T EIE EE E R3 To F R2 T DE CF T 3 Measured temperature using thermometer T _3 Value of R from display of 7102 Press SET and DOWN at the same time Calibration Procedure 1 2 12 2 Calibration Procedure where T and Ri are the measured temperature and resistance at 50 0 C T and R are the measured temperature and resistance at 90 0 C Ts and R3 and R are the measured temperature and resistance at 150 0 C 12 2 2 Compute R0 amp ALPHA a T delta EI T a T delta KE vi rzero ME a 43 R R 34 Ra Where delta is the new value of DELTA computed above Program the new values for DELTA delta RO rzero and ALPHA alpha into the Micro Bath with the following steps alpha e Press SET and EXIT keys at the same time and then press UP u
17. specifications For protection against solid state relay failure or other circuit failure a bi metallic cut out automatically turns off the heater anytime the bath temperature exceeds the maximum temperature The controller allows the operator to set the bath temperature with high resolution adjust the proportional band monitor the heater output power and program the controller configuration and calibration parameters The controller may be operated in temperature units of degrees Celsius or Fahrenheit The controller is operated and programmed from the front control panel using the four key switches and digital LED display The controller is equipped with a serial RS 232 digital interface for remote operation Operation using the digital interfaces is discussed in Section 10 When the controller is set to a new set point the bath heats or cools to the new temperature Once the new temperature is reached the bath usually takes 15 20 minutes for the temperature to settle and stabilize There may be a small overshoot or undershoot 7102 User s Guide 8 10 Chapter 9 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 display the user may monitor the well temperature set the temperature set point in degrees C or F monitor the heater output power adjust the controller proportional band and program the calibrat
18. struck stressed or overheated e When calibrating PRTs always follow correct calibration procedure and calibrate from high temperatures to low temperatures with the appropriate triple point of water checks e Components and heater lifetimes can be shortened by continuous high temperature operation e Ifa mains supply power fluctuation occurs immediately turn off the bath Power bumps from brown outs and black outs can damage the instrument Wait until the power has stabilized before re energizing the bath e Fluids may expand at different rates Allow for fluid expansion inside the well as the instrument heats Otherwise the fluid may overflow the well and leak into the instrument 1 3 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 E mail support hartscientific com 1 5 7102 User s Guide 1 6 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 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 6 512 3436 Telefax 86 10 6 512 3437 E m
19. 10 200 20 8 4 8 3 11 Fluid Characteristics Charts 8 3 11 1 Limitations and Disclaimer iese esse ee Ee Ee Ee ee ee 8 5 8 3 NNN 8 6 Ou SIG eee 8 7 FONN NN 8 6 Thermal Electric Devices TED 8 8 ON 8 8 Temperature Controller iese se ee ee ee EE ee EE ee EE ER ee ee ee ee ee 9 Controller Operation ese RE RE ER RE ER RE ER RE ER Re ER Ee ER EE ERGE RR EE ERGE RR EE REENEN 9 1 Well Temperature KHE 9 2 Temperature Getpomt ese ese see se ee ee ER EE ee Ee Ee Ee ee ee ee ee ee ee ee ee ee ee 9 2 1 Programmable Get pomts esse sees se ee ee Ee ee EE ee EE ee ee RE Ee ee ee Kap 9 2 2 Set point Value cece EER EE ee ee ee ee ee ee ee ee ee ee ee ee ee 9 2 3 Temperature Scale Une ee ee ee ee EE ER EE ER EE ER ee ee ee ee 9 3 SE CIA EEE EE NE EE 9 4 JER SCM CONTON E 9 4 9 82 SCAN RANG EE 9 4 9 4 Temperature Display Hold 9 4 9 4 1 Hold Temperature Display 9 5 J42 Mode NN 9 5 9 4 3 Switch Wumg cece cece ee EE Ee Ee RR ee ee Ee ee ee Ee ee Ee RE ee ee ee 9 5 9 4 4 Switch Test Exame 9 6 9 5 Secondary Menu rarrnnnnnnanrnnnnevnnnnnnnnnanennnnnnanennnsnnanennnnnnanennnsennnennn HD 9 6 Thermal Electric Device TED 9 6 9 7 Proportional Band 9 f 9 8 Controller Configuration ee ee Ee ee EE ee EE ee Ee ee ee RE ee ee ee ee Contents continued 9 8 1 Operating Parameters rrrrrrnanrnnnnnranernnrrnanrnnnnnvanennnnnnanenanennnne 9 8 9 8 1 1 High Um 9 9 io UI OC sae eo ER EE EG Ee RE
20. 2 port Refer to Section 9 8 2 Serial Interface Parameters for instructions on configuring the RS 232 communications interface 9 5 Secondary Menu Functions which are used less often are accessed within the secondary menu The secondary menu is accessed by pressing SET and EXIT simultaneously and then releasing The first function in the secondary menu is the heater power display See Figure 7 on page 32 9 6 Thermal Electric Device TED The temperature controller controls the temperature of the well by pulsing the TED on and off The total power being applied to the TED is determined by the duty cycle or the ratio of TED on time to the pulse cycle time By knowing the amount of heating the user can tell if the calibrator is heating up to the set point cooling down or controlling at a constant temperature Monitoring the percent heater power will let the user know how stable the well temperature is With good control stability the percent heating power should not fluctuate more than 5 within one minute 9 6 Controller Operation 9 7 Proportional Band The heater power display is accessed in the secondary menu Press SET and EXIT simultaneously and release The heater power will be displayed as a percentage of full power SEG Flashes 420P Heater power in percent To exit out of the secondary menu hold EXIT To continue on to the proportional band setting function press EXIT momenta
21. 230 VAC 50 60 Hz Switching the voltage can change the calibration so the unit should be calibrated after changing the input voltage To change from 115 VAC to 230 VAC e Unplug the unit e With a small straight slot screwdriver remove the fuse holder located on the back of the bath Replace the two fuses 3 amp 250 V with 1 6 amp 250 V fuses e Replace the fuse holder with the 230V in the display window Note Use 3 amp fuses for 115 V and 1 6 amp for 230V only DO NOT PLUG THE UNIT INTO 230 V IF THE FUSE HOLDER READS 115 V 8 1 7102 User s Guide 8 2 8 3 Bath Fluid Many fluids work with the 7102 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 electrical resistivity fluid lifetime safety and cost 8 34 1 Temperature Range One of the most important characteristics to consider is the temperature range of the fluid Few fluids work well throughout the complete 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 The lower temperature range of the fluid is determined 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 Vaporiza
22. 7 3 Accessories Power Switch The power switch is located on the power entry module PEM The PEM also houses the fuses and the dual voltage selector The PEM allows the unit to be field switchable for 115 VAC 10 or 230 VAC 10 operation Serial Port A DB 9 male connector is present for interfacing the calibrator to a computer or terminal with serial RS 232 communications Fan The fan inside the calibrator runs continuously when the unit is being operated to provide cooling for the instrument Slots at the top and around the two corners of the calibrator are provided for airflow The area around the calibrator must be kept clear to allow adequate ventilation The airflow is directed out the back 7 3 Accessories 7 3 1 Transport Pour Access Lid A transport pour access lid Figure 3 is provided so the fluid being does not have to be removed when transporting The lid doubles as a pour spout Pour Spout Pour Spout Cover Transport Plug Transport Pour Access Lid Optional Access Cover nn Figure 3 Bath Lids and Lid Parts 7 7 3 7102 User s Guide 7 3 2 Access Cover Optional An aluminum access cover Figure 3 is available for optimum stability Holes should be drilled in the access cover to allow insertion of the probes into the well The holes must be within the guide ring for the probes to fit into the probe basket Warning DO NOT install an access cover without holes like the opt
23. PN 3729328 December 2013 2013 Fluke Corporation All rights reserved Specifications are subject to change without notice All product names are trademarks of their respective companies Calibration 7102 Micro Bath User s Guide 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 international pric
24. S 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 To register your product online visit register fluke com Table of Contents Chapter Title Page 1 BST OVE VOU Sa E 1 1 SEE NN 1 2 Safety Information ee ee ee ee EE ee EE ee Ee Ee ee EE ee ee Ee ee ee ee ee Ee ee ee val VANG 1 2 2 e ele si Se DEE ee ei ie ei ed ee viet Ga er AE IE 1 3 Authorized KE le CC 2 Idee e UL CLOUD EE EE N EE N ER EE 3 Specifications and Environmental Conditions Gesie 111652 og SES e EO N OR N NN 3 2 Environmental ConditiONS ees see see ee ee ee ee ee ee ee ee ee ee ee ee 4 QUI e dE Aal Pe NR leet UNG DE ZS WO EE AS OW E 4 4 Setting t
25. ail xingye han fluke com cn Fluke South East Asia Pte Ltd Fluke ASEAN Regional Office Service Center 60 Alexandra Terrace 03 16 The Comtech Lobby D 118502 SINGAPORE Phone 65 6799 5588 Telefax 65 6799 5589 E mail anthony ng fluke com When contacting these Service Centers for support please have the following information available e Model Number e Serial Number e Voltage e Complete description of the problem Chapter 2 Introduction The Hart Scientific 7102 Micro Bath may be used as a portable instrument or bench top temperature calibrator for calibrating thermocouple and RTD temperature probes The 7102 is small enough to use in the field and accurate enough to use in the lab With an ambient temperature of 23 C 74 F calibrations may be done over a range of 5 C to 126 C 23 F to 259 F The resolution of the 7102 temperature display is 0 01 degrees The Micro Bath calibrator features e Convenient handle e RS 232 interface e Switchable AC Input 115 VAC or 230 VAC e Optional well extender to extend well depth Built in programmable features include e Temperature scan rate control e Temperature switch hold e Eight Set point memory e Adjustable readout in C or F The temperature is accurately controlled by Hart s hybrid analog digital controller The controller uses a precision platinum RTD as a sensor and controls the well temperature with a solid state relay triac driven heater
26. alibration Label Access Cover optional Well Extender optional 4 1 7102 User s Guide 4 2 4 2 Setup Caution DO NOT operate this instrument without fluid Place the calibrator on a flat surface with at least 6 inches of free space around the instrument Plug the power cord into a grounded mains outlet Observe that the nominal voltage corresponds to that indicated on the back of the calibrator Carefully insert the probe basket into the well Fill the well with the appropriate fluid The set point temperature and the number of and size of probes determine the fluid level Be sure to keep the fluid level an adequate distance below the top of the well to prevent overflowing the fluid when the probes are inserted For example placing200 05 oil at room temperature 25 C into the bath and heating the unit to 125 C causes a 1 inch 2 54 cm expansion of the fluid inside the well Keep the fluid level at least 1 9 cm 0 75 inches below the top of the well at all times With the probe probes in the well fill the tank 3 4 full Heat to the maximum temperature of the fluid Slowly fill the well to 2 54 cm 1 inch below the top of the basket at the maximum temperature of the fluid Turn on the power to the calibrator by toggling the switch on the power entry module The fan should begin blowing air through the instrument and the controller display should illuminate after 3 seconds After a brief self test the controller should
27. 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 will not be as good Mineral oil has very low electrical conductivity Use caution with mineral oil since it is flammable and may also Cause serious injury if inhaled or ingested 8 3 10 3 Silicone Oil Dow Corning 200 05 200 10 200 20 Silicone oils are available which offer a much wider operating temperature range than mineral oil Like most oils silicone oils have temperature control characteristics which are somewhat poorer than water The viscosity changes significantly with temperature and thermal expansion also occurs These oils have very high electrical resistivity Silicone oils are fairly safe and non toxic Silicone oils are fairly expensive 8 3 11 Fluid Characteristics Charts Table 3 on page 25 and Figure 6 on page 26 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 often used as heat transfer fluid in baths Because of the temperature range some fluids may not be useful with your bath General Operation 8 3 Bath F
28. begin normal operation If the unit fails to operate please check the power connection The display shows the well temperature and the well TEDs start operating to bring the temperature of the well to the set point temperature Insure that the fluid is being stirred 4 3 Power 4 4 Plug the Micro Bath power cord into a mains outlet of the proper voltage frequency and current capability Refer to Section 3 1 Specifications for power details Turn the bath on using the rear panel POWER switch The Micro Bath will turn on and begin to heat to the previously programmed temperature set point The front panel LED display will indicate the actual bath temperature Setting the Temperature Section 9 2 explains in detail how to set the temperature set point on the calibrator using the front panel keys The procedure is summarized here 1 Press SET twice to access the set point value 2 Press UP or DOWN to change the set point value 3 Press SET to store the new set point 4 Press EXIT to return to the temperature display When the set point temperature is changed the controller switches the heater on or off to raise or lower the temperature The displayed well temperature gradually changes until it reaches the set point temperature The well may require 25 minutes to reach the set point depending on the span Another 10 to 15 minutes is required to stabilize within 0 03 C of the set point Ultimate stabili
29. choed The duplex mode parameter is indicated by dUPL Flashes dUPL and then displays the setting 9 10 L Controller Operation O 9 8 Controller Configuration 9 8 2 4 Linefeed The final parameter in the serial interface menu is the linefeed mode This parameter enables on or disables off transmission of a linefeed character LF ASCII 10 after transmission of any carriage return The linefeed parameter is indicated by LF Flashes LF and then displays the setting LF OFF l New linefeed setting Calibration Parameters The operator of the Micro Bath controller has access to a number of the bath calibration constants namely RO ALPHA DELTA CO CG and rCAL These values are set at the factory and should not be altered The correct values are important to the accuracy and proper and safe operation of the bath Access to these parameters is available to the user only so that in the event that the controller memory fails the user may restore these values to the factory settings The user should have a list of these constants and their settings with manual Caution DO NOT change the values of the bath calibration constants from the factory set values The correct setting of these parameters is important to the safety and proper operation of the bath The calibration parameters menu is indicated by CAL Calibration parameters menu Press SET five times to enter the menu The calibrat
30. ct to the material If the mains supply cord becomes damaged replace it with a cord with the appropriate gauge wire for the current of the instrument If there are any questions call an Authorized Service Center for more information Before using any cleaning or decontamination method except those recommended by Hart users should check with an Authorized Service Center to be sure that the proposed method will not damage the equipment If the instrument is used in a manner not in accordance with the equipment design the operation of the Micro Bath may be impaired or safety hazards may arise 13 1 7102 User s Guide 13 2 Chapter 14 Troubleshooting This section contains information on troubleshooting and CE Comments 14 1 Troubleshooting Problems Possible Causes and Solutions 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 problem cannot otherwise be solved contact an Authorized Service Center see Section 1 3 Be sure to have the model number and serial number of your instrument available Incorrect temperature reading Incorrect RO ALPHA and DELTA parameters Find the value for RO ALPHA and DELTA on the Report of Calibration that was shippe
31. d with the instrument Reprogram the parameters into the instrument see Section 9 8 3 Calibration Parameters Allow the instrument to stabilize and verify the accuracy of the temperature reading Controller locked up The controller may have locked up due to a power surge or other aberration Initialize the system by performing the Factory Reset Sequence Factory Reset Sequence Hold the SET and EXIT buttons down at the same time while powering up the instrument The instrument displays shows init the model number and the firmware version Each of the controller parameters and calibration constants must be reprogrammed The values can be found on the Report of Calibration that was shipped with the instrument 14 1 7102 User s Guide The instrument heats or cools too quickly or Incorrect scan and scan rate settings The too slowly scan and scan rate settings may be set to unwanted values Check the Scan and Scan Rate settings The scan may be off if the unit seems to be responding too quickly The scan may be on with the Scan Rate set low if unit seems to be responding too slowly D 37 An o is displayed at the left of the display External switch is open The external switch is open causing the displayed temperature to be frozen and keeping the set point from scanning Turn the switch test off by pressing the DOWN button on the front panel The display shows any error Controller problem The error mes
32. e 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 products 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 WARRANTIE
33. e These guidelines must be followed to ensure that the safety mechanisms in this instrument will operate properly This instrument must be plugged into an AC only electric outlet as listed in Section 3 1 Specifications 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 ordinances or adapter plug DO NOT use an extension cord Consult a qualified electrician Always inspect the power cord before use for any damage to the insulation due to contact with hot surfaces cuts or abrasions e The instrument is equipped with operator accessible fuses If a fuse blows it may be due to a power surge or failure of a component Replace the fuse once If the fuse blows a second time it is likely caused by failure of a component part If this occurs contact a Hart Scientific Authorized Service Center Always replace the fuse with one of the same rating voltage and type Never replace the fuse with one of a higher current rating e Always replace the power cord with an approved cord of the correct rating and type If you have questions contact an 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 preca
34. e fluid Thermal conductivity of the fluid affects the control stability temperature uniformity and probe temperature settling time Fluids with higher conductivity distribute heat more quickly and evenly improving bath performance General Operation 8 3 Bath Fluid 8 3 5 Thermal Expansion Thermal expansion describes how the volume of the fluid changes with temperature Thermal expansion of the fluid used must be considered since the increase in fluid volume as the bath temperature changes may cause overflow Excessive thermal expansion may also be undesirable in applications where constant liquid level is important Many fluids including oils have significant thermal expansion 8 3 6 Electrical Resistivity Electrical resistivity describes how well the fluid insulates against the flow of electric current In some applications such as measuring the resistance of bare temperature sensors it may be important that little or no electrical leakage occur through the fluid In such conditions choose a fluid with very high resistivity 8 3 7 Fluid Lifetime 8 3 8 Many fluids degrade over time because of evaporation water absorption gelling 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 associated Obviously where there are conditions of extreme hot or cold there can
35. eat 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 reflective metal apparatus When calibrating over a wide temperature range better results can generally be achieved by starting at the highest temperature and progressing down to the lowest temperature 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 object 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 6 3 Calibration of Multiple Probes Fully loading the bath with probes increases the time required for the temperature to stabilize after inserting the probes Using the reference probe as the guide be sure that the temperature has stabilized before starting the calibration Chapter 7 Parts and Controls The user should become familiar with the bath and its parts 7 1 Front Panel Figure 1 on this page 7102 MICRO BATH 5 C to 125 C Callibrat
36. energy consuming equipment to be supplied from the fixed installation Examples include household office and laboratory appliances ma o C TICK Australian EMC mark The European Waste Electrical and Electronic Equipment WEEE Directive 2002 96 EC mark Pl PEIP 7102 User s Guide 1 2 1 2 Safety Information Use this instrument only as specified in this manual Otherwise the protection provided by the instrument maybe 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 and actions that may damage the instrument being used 1 2 1 Warnings A Warnings To avoid personal injury follow these guidelines Disclaimer Hart Scientific manufactures instruments for the purpose of temperature calibration Instruments used for applications other than calibration are used at the discretion and sole responsibility of the customer Hart Scientific cannot accept any responsibility for the use of instruments for any application other than temperature calibration GENERAL DO NOT install an access cover without holes onto a bath that is energized Dangerous pressures may result from fluids vaporizing 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 cau
37. ess SET to accept the new value and access the temperature scale units selection If EXIT is pressed instead of SET any changes made to the set point are ignored e SET Accept new set point value 9 2 3 Temperature Scale Units The temperature scale units of the controller can be set by the user to degrees Celsius C or Fahrenheit F The selected units are used in displaying the well temperature set point and proportional band Press SET after adjusting the set point value to change display units Un C Scale units currently selected 7102 User s Guide 9 3 Scan 9 3 1 9 3 2 The scan rate can be set and enabled so that when the set point is changed the bath heats or cools at a specified rate degrees per minute until it reaches the new set point With the scan disabled the bath heats or cools at the maximum possible rate Scan Control The scan is controlled with the scan on off function that appears in the main menu after the set point function Sc OFF l Scan function off Press SET to accept the present setting and continue SET Accept scan setting Scan Rate The next function in the main menu is the scan rate The scan rate can be set from 1 to 99 9 C min The maximum scan rate however is actually limited by the natural heating or cooling rate of the instrument This is often less than 100 C min especially when cooling The scan rate function appears in the
38. ger or impracticality 8 4 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 adjusted for optimum performance Table 4 on page 27 shows nominal stirrer motor settings for several fluids If the stirrer does not function properly the instrument will oscillate and not meet published specifications Note If the bath is used with the probe basket removed stir motor settings need to be changed so that a small vortex can be seen in the liquid 8 7102 User s Guide A Warning Do not mix water and oil when exceeding temperatures of 90 C Table 4 Nominal Stirrer Motor Settings with Different Liquids Distilled Water 15 5 C to 90 C 41 F to 194 F Ethylene Glycol 15 5 C to 90 C 25 F to 194 F 200 05 Oil 15 5 C to 125 C 23 F to 258 F 200 10 Oil 15 25 C to 125 C 77 F to 258 F 8 5 Power Power to the bath is provided by an AC mains supply and passes through a filter to prevent switching spikes from being transmitted to other equipment Refer to Section 3 1 Specifications for power details To turn on the bath switch the control panel power switch to the ON position The stir motor will turn on the LED display will begin to show the bath temperature and the heater will turn on or off until the bath temperature reaches the programmed set
39. he Temperature 5 FE id ei EE EE EN EK 51 Bali EMV IMONIMEIL EE 5 1 OZ Div oul FP SOG EE DT 5 3 Bath Preparation and Filling ese sees se ee Ee Ee EE ee Ee ee ee ee Ee ee ee ee 5 2 OW E 5 2 6 Bath Use nanne 6 1 General EEE EE 6 2 Comparison Calibration ees ee ee ee ee ee ee EE ER EE ER EE ER ee ee ee ee ee ee ee 6 3 Calibration of Multiple Drobes iese see see see ee ee ee ee ee ee ee ee ee ee ee 7102 User s Guide 7 Parts NINE PP Zai k Back PN E VE PP SEE EN 7 3 1 Transport Pour Access d 3 7 3 2 Access Cover Optional ee Ee RE ER EE ee EE Re Ee RE ee EE CZ 23 3 Probe Basket E LC 164 et E 4 7 3 5 Well Extender Optional ese ee ee ee Ee ee EE ee Ee ee Ee ee Ee ee ee ee 8 General Operation EE EE N ER 8 1 Changing Display Units Lua sb ee Ee Ee EE Ee Ee De RE 8 1 8 2 Switching to 230V Operation rrrarrranrrnnrernrrrrarennrevnnnnvanennnnennnnnn 8 1 OU FIG EE ME DE T 8 3 1 Temperature Range ccccccscccsccceecceeceeeceeeseeeseeesseeseeeneeenes 8 2 ons Ee le E 8 2 eege HER sk n EG Oe N og ER GO De 8 2 8 3 4 Thermal Conduchivifv ees ee ee ee Ee ER Ee RE RR EE ee EE ee ee RE ee Ee 8 3 5 Thiermal EXPANSION EE 8 3 6 Electrical Resistivity asia 8 3 8 3 FOG Hileli ss esse GE EE De E N Go 8 3 DS SN OS E 8 3 8 3 10 Commonly Used FluidS eie ee ee EE ee EE Ee RE Ee RE ee EE ee ee 8 3 10 1 Water RTE d 8 4 Sa O EE 8 3 10 3 Silicone Oil Dow Corning 200 05 200
40. he sample period is the time period in seconds between temperature measurements transmitted from the serial interface If the sample rate is set to 5 the instrument transmits the current measurement over the serial interface approximately every five seconds The automatic sampling is disabled with a sample period of 0 Press SET to choose to set the sample period Adjust the period with UP or DOWN and then use SET to set the sample rate to the displayed value 10 1 2 3 Duplex Mode The next parameter is the duplex mode indicated with AUPL The duplex mode may be set to half duplex HALF or full duplex FULL With full duplex any commands received by the thermometer via the serial interface will be immediately echoed or transmitted back to the device of origin With half duplex the commands will be executed but not echoed The default setting is full duplex The mode may be changed using UP or DOWN and pressing SET 10 1 2 4 Linefeed The final parameter in the serial interface menu is the linefeed mode This parameter enables On or disables OFF transmission of a linefeed character LF ASCII10 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 10 1 3 Serial Operation Once the cable has been attached and the interface set up properly the controller will immedia
41. ian Figure 1 7102 Front Panel Controller Display The digital display is an important part of the temperature controller because it not only displays set and actual temperatures but also displays various calibrator functions settings and constants The display shows temperatures in units according to the selected scale C or F Controller Keypad The four button keypad allows easy setting of the set point temperature The control buttons SET DOWN UP and EXIT are used to set the calibrator temperature set point access and set other operating parameters and access and set calibration parameters Setting the control temperature is done directly in degrees of the current scale It can be set to one hundredth of a degree Celsius or Fahrenheit The functions of the buttons are as follows SET Used to display the next parameter in the menu and to store parameters to the displayed value DOWN Used to decrement the displayed value of parameters UP Used to increment the displayed value 7 1 7102 User s Guide EXIT Used to exit a function Any changes made to the displayed value are ignored Holding the EXIT button for approximately 0 5 seconds exits back to the main display 7 2 Back Panel Figure 2 on next page Power Cord Underneath the calibrator is the removable power cord inlet that plugs into an IEC grounded socket Figure 2 7102 Back Panel and Bottom 1 2 Parts and Controls
42. ideration when choosing a fluid 7102 User s Guide 8 3 10 Commonly Used Fluids Below is a description of some of the more commonly used fluids and their characteristics 8 3 10 1 Water Distilled Water is often used because of its very low cost availability and excellent temperature control characteristics Water has very low viscosity and good thermal conductivity and heat capacity which makes it among the best fluids for control stability at low temperatures Temperature stability is much poorer at higher temperatures because water condenses on the lid cools and drips into the bath Water is safe and relatively inert The electrical conductivity of water may prevent its use in some applications Water has a limited 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 softened to prevent mineral deposits Consider using an algaecide chemical in the water to prevent contamination 8 3 10 2 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 use of a fume hood is highly recommended As with most oils mineral oil will expand as temperature increases so
43. ing on the desired temperature range any of the following fluids as well as others may be used in the bath e Water distilled e Ethylene glycol water e Mineral oil e Silicone oil Fluids are discussed in detail in Section 8 3 Remove the access lid from the bath and check the tank for foreign matter dirt remnant packing material etc Thoroughly dry the inside of the well with paper towels before filling Fill the bath with clean unpolluted fluid Under filling may reduce bath performance The fluid should never exceed a height of 1 9 cm 0 75 inches below the top of the basket Carefully monitor the bath fluid level as the bath temperature rises to prevent overflow or splashing Remove excess hot fluid if necessary with caution Note 200 05 Silicon Oil expands 2 54 cm 1 inch for a 100 increase in temperature 5 4 Power With the bath power switch off plug the bath into an AC mains outlet of the appropriate voltage frequency and current capacity Refer to Section 3 1 Specifications for power details D 2 Chapter 6 Bath Use Caution Read before placing the bath in service The information in this section is for general information only It is not designed to be the basis for calibration laboratory procedures Each laboratory will need to write their own specific procedures 6 7 General Be sure to select the correct fluid for the temperature range of the calibration Bath fluids should be selected
44. ion parameters operating parameters and serial interface configuration Operation of the functions and parameters are shown in the flowchart in Figure 7 on page 32 This chart may be copied for reference In the following discussion a button with the word SET UP EXIT or DOWN inside indicates the panel button while the dotted box indicates the display reading Explanation of the button or display reading are to the right of each button or display value 9 1 Well Temperature The digital LED display on the front panel allows direct viewing of the actual well temperature This temperature value is what is normally shown on the display The units C or F of the temperature value are displayed at the right For example CTT TTT 100 00C Well temperature in degrees Celsius EEN KA ee 4 The temperature display function may be accessed from any other function by pressing the EXIT button 9 2 Temperature Set point The temperature set point can be set to any value within the range and resolution as given in the specifications Be careful not to exceed the safe upper temperature limit of any device inserted into the well Setting the temperature involves selecting the set point memory and adjusting the set point value 9 2 1 Programmable Set points The controller stores 8 set point temperatures in memory The set points can be quickly recalled to conveniently set the calibrator to a previously programmed temperature set point
45. ion parameters RO ALPHA DELTA CO CG and rCAL characterize the resistance temperature relationship of the platinum control sensor These parameters may be adjusted by an experienced user to improve the accuracy of the calibrator 7102 User s Guide 9 8 3 1 RO This probe parameter refers to the resistance of the control probe at 0 C The value of this parameter is set at the factory for best instrument accuracy 9 8 3 2 ALPHA This probe parameter refers to the average sensitivity of the probe between 0 and 100 C The value of this parameter is set at the factory for best instrument accuracy 9 8 3 3 DELTA This probe parameter characterizes the curvature of the resistance temperature relationship of the sensor The value of this parameter is set at the factory for best instrument accuracy 9 8 3 4 CO and CG These parameters calibrate the accuracy of the bath set point These are programmed at the factory when the bath is calibrated DO NOT alter the value of these parameters If the user desires to calibrate the bath for improved accuracy then calibrate RO and ALPHA according to the procedure in Section 12 9 8 3 5 rCAL DO NOT adjust this parameter It is for factory use only Chapter 10 Digital Communication Interface The Micro Bath calibrator is capable of communicating with and being controlled by other equipment through the digital serial interface With a digital interface the instrument may be connected to a c
46. ional cover onto a bath that is energized Dangerous pressures may result from fluids vaporizing 7 3 3 Probe Basket A probe basket Figure 4 is provided as a guide for the probes and to prevent bumping of the stir bar Figure 4 Probe Basket 7 3 4 Stir Bar The stir bar Figure 5 sits in the bottom of the well for mixing the fluid providing better accuracy uniformity and stability ec N We e Figure 5 Stir Bar 7 3 5 Well Extender Optional An optional well extender is available for increasing the depth of the well This extender screws onto the well and is equipped with an O ring Thread the extender down until the O ring makes a good seal Some fluids may expand up to 6 35 cm 2 5 inches Therefore when using the well extender keep in mind how much the fluid you are using will expand Do not overfill the well 7 4 Chapter 8 General Operation 8 1 Changing Display Units The 7102 can display temperature in Celsius or Fahrenheit The temperature units are shipped from the factory set to Celsius To change to Fahrenheit or back to Celsius there are two ways 1 Press SET and UP simultaneously This will change the display units 2 Press the SET key three times from the temperature display to show e mm P Ten mm ri or e Press the UP or DOWN key to change units e Press SET to store changes 8 2 Switching to 230V Operation The 7102 is switchable from 115 VAC to
47. is easily adjusted from the front panel The width may be set to discrete values in degrees C or F depending on the selected units The proportional band adjustment is be accessed within the secondary menu Press SET and EXIT to enter the secondary menu and show the heater power Then press SET to access the proportional band EXIT Access heater power in secondary menu 12 0 P Heater power in percent se Access proportional band ProP Flashes ProP and the setting 5 0 Proportional band setting 4 0 New proportional band setting To store the new setting press SET Press EXIT to continue without storing the new value F SET Accept the new proportional band setting 9 8 Controller Configuration The controller has a number of configuration and operating options and calibration parameters which are programmable via the front panel These are accessed from the secondary menu after the proportional band function by pressing SET Pressing SET again enters the first of three sets of configuration parameters operating parameters serial interface parameters and calibration parameters The menus are selected using the UP and DOWN keys and then pressing SET See Figure 7 on page 32 9 8 1 Operating Parameters The operating parameters menu Is indicated by PAr l Operating parameters menu The operating parameters menu contains the High Limit and Stir Speed
48. luid 8 3 11 1 Limitations and Disclaimer The information given in this manual regarding fluids is intended only to be used as a general guide in choosing a fluid Though every effort has been made to provide correct information we cannot guarantee accuracy of data or assure suitability of a fluid for a particular application Specifications may change and sources sometimes offer differing information Hart Scientific cannot be liable for any personal injury or damage to equipment product or facilities resulting from the use of these fluids The user of the bath is responsible for collecting correct information exercising proper judgment and insuring safe operation Operating near the limits of certain properties such as the flash point or viscosity can compromise safety or performance Your company s safety policies regarding flash points toxicity and such issues must be considered You are responsible for reading the MSDS material safety data sheets and acting accordingly Table 3 Table of Various Bath Fluids Fluid Lower Upper Specific Thermal Thermal Hart Temperature Temperature Flash Viscosity Specific Heat Conductivity Expansion Resistivity Part No Limit Limit Point centistokes Gravity cal g C cal s cmi C emeni C 102 O cm Halocarbon 90 C v 70 G a NONE 5 7 50G 1716 40 C 0 2 0 0004 0 0011 0 8 0 8 40 C CD 0 5 70 C Methanol 96 C fr 60 C b 54 C 13 35 C 0 810 amp OG 0 6 0 0005 amp 20 C 0 0014
49. mperature Display is being used the temperature at which the switch is activated does not affect the set point temperature However if the Scan Control is ON and the Hold Temperature Display is being used the temperature at which the switch is activated is stored as the new set point temperature Operation of the hold temperature display is outlined below 8 143 50C Well temperature display D Access hold display i c 144 8 Switch status and hold temperature To return to the normal well temperature display press DOWN 9 4 2 Mode Setting The Hold Function is always in the automatic mode In this mode the normal position is set to whatever the switch position is when the set point is changed For example if the switch is currently open when the set point is changed the closed position then becomes the new active position The normal position will be set automatically under any of the following conditions 1 a new set point number is selected 2 the set point value is changed 3 a new set point is set through the communications channels 9 4 3 Switch Wiring The thermal switch or cut out is wired to the calibrator at the two terminals on the back of the Micro Bath labeled DISPLAY HOLD The switch wires may be connected to the terminals either way Internally the black terminal connects to ground The red terminal connects to 5V through a 100 kW resistor The calibrator measures the voltage at the red termi
50. nal and interprets 5V as open and OV as closed 7102 User s Guide 9 4 4 Switch Test Example This section describes a possible application for the temperature hold feature and how the instrument is set up and operated Suppose you have a thermal switch which is supposed to open at about 75 C and close at about 50 C and you want to test the switch to see how accurate and repeatable it is You can use the temperature hold feature and the scan function to test the switch Measurements can be made by observing the display or preferably by collecting data using a computer connected to the RS 232 port To set up the test do the following steps 1 Connect the switch wires to the terminals on the back of the Micro Bath and place the switch in the well 2 Enable set point scanning by setting the scan to ON in the primary menu see Section 9 3 1 3 Set the scan rate to a low value say 1 0 C min see Section 9 3 2 If the scan rate is too high you may lose accuracy because of transient temperature gradients If the scan rate is too low the duration of the test may be longer than is necessary You may need to experiment to find the best scan rate 4 Set the first program set point to a value above the expected upper switch temperature say 90 C 5 Set the second program set point to a value below the expected lower switch temperature say 40 C in the program menu 6 Collect data on a computer connected to the RS 23
51. ntil CAL is displayed e Press SET five times until RO is displayed e Press SET then use the UP or DOWN keys until the correct numerical setting is displayed Press SET to accept the new value e Repeat step 2 for ALPHA and DELTA 12 2 3 Accuracy amp Repeatability Check the accuracy of the Micro Bath at various points over the calibrated range If Micro Bath does not pass specification at all set points repeat the Calibration Procedure 12 3 7102 User s Guide 12 4 Chapter 13 Maintenance 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 an oily wet dirty or dusty environment If the outside of the instrument becomes soiled it may be wiped clean with a damp cloth and mild detergent Do not use harsh chemicals on the surface which may damage the paint It is important to keep the well of the calibrator clean and clear of any foreign matter DO NOT use chemicals to clean the well The bath should be handled with care Avoid knocking or dropping the instrument lf a hazardous material is spilt on or inside the equipment the user is responsible for taking the appropriate decontamination steps as outlined by the national safety council with respe
52. o 40 Read high limit hi hl hl 999 hl 126 Set high limit hl n hl 90 0 126 Serial Interface Menu Read serial sample setting sa mple sa sa 9 sa 1 Set serial sampling setting ton salmplel n sa 0 0 to 999 seconds Set serial duplex mode dufplex ffull h alf FULL or HALF Set serial duplex mode to full duf plex ffull du f Set serial duplex mode to half dufplex hjalf du h Set serial linefeed mode Heedl on offf ON or OFF Set serial linefeed mode to on lHeedl on lf on Set serial linefeed mode to of lfeedl offl lf of Calibration Menu Read RO calibration parameter do r r0 999 999 r0 100 578 Set RO calibration parameter to n r 0 n r 100 324 90 to 110 Read ALPHA calibration al pha al al 9 9999999 al 0 0038573 parameter Set ALPHA calibration parameter al phaj n al 0 0038433 002 to 005 ton Read DELTA calibration dellta de de 9 99999 de 1 507 parameter Set DELTA calibration parameter delltal n de 1 3742 0 3 0 Read CO calibration parameter cloi c c0 99 9999 c0 0 297 Set CO calibration parameter c O n c 5 113 Read CG calibration parameter cg cg cg 99 999 cg 0 555 Set CG calibration parameter cg n og 4 115 Functions not on menu Read firmware version number ver sion ver ver 3999 9 99 ver 7102 2 00 Read structure of all commands help h list of commands Read all operating parameters all all list of parameters Legend Optional Command data Returns either information n Numeric data supplied by user 9 Numeric da
53. omputer or other equipment This allows the user to set the set point temperature monitor the temperature and access any of the other controller functions all using remote communications equipment Communications commands are summarized in Table 5 10 1 7102 User s Guide 10 2 10 1 Serial Communications The calibrator is installed with an RS 232 serial interface that allows serial digital communications over fairly long distances With the serial interface the user may access any of the functions parameters and settings discussed in Section 9 with the exception of the baud rate setting 10 1 1 Wiring N The serial communications cable attaches RS 232 Cable Wiring for to the calibrator through the DB 9 connector IBM PC and Compatibles at the back of the instrument Figure 8 shows the pin out of this connector and T RE Instrument Computer OTE suggested cable wiring To eliminate noise Cannecter Connector the serial cable should be shielded with low Pasen enn resistance between the connector DB 9 Kee e o ze and the shield If the unit is used in a heavy 3TXD yt 3TXD industrial setting the serial cable must be lk Gre limited to ONE METER in length ENC Te 6 DSR TARTS pg TTS 10 1 2 Setup ER pr Sg DOS Before operation the serial interface must ee e first be set up by programming the baud rate and other configuration parameters KEE AE EE These parameters are programmed within Connector Connector
54. ower line If the fluid is not stirring turn the instrument off for one minute 14 2 Troubleshooting 1 4 14 2 Comments AC voltage present on the chassis Use a wall plug tester to check the main power plug at the wall Use an ohmmeter to check the continuity between the ground prong on the PEM and the chassis If the resistance reading is greater than three ohms there is a problem Check the power cord for continuity on the ground prongs If the resistance is greater than one ohm replace the power cord 14 2 Comments 14 2 1 EMC Directive Hart Scientifics equipment has been tested to meet the European Electromagnetic Compatibility Directive EMC Directive 89 336 EEC The Declaration of Conformity for your instrument lists the specific standards to which the unit was tested 14 2 2 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 EN 61010 1 and EN 61010 2 010 standards 14 3 7102 User s Guide 14 4
55. r 230 VAC 10 0 9 A switchable 50 60 Hz 200 W Overvoltage Installation Category II Pollution Degree 2 per IEC 61010 01 115 V 250 V 3A SB slow blow 230 V 250 V 1 6 AT time delay 3 1 7102 User s Guide 3 2 3 2 Environmental Conditions Although the instrument has been designed for optimum durability and trouble free operation it must be handled with care The instrument should not be operated in an excessively dusty or dirty environment Maintenance and cleaning recommendations can be found in the Maintenance Section of this manual The instrument operates safely under the following conditions ambient temperature range 5 45 C 41 113 F ambient relative humidity maximum 80 for temperature lt 31 C decreasing linearly to 50 at 40 C mains voltage within 10 of nominal vibrations in the calibration environment should be minimized altitudes less than 2 000 meters Chapter 4 Quick Start Caution READ SECTION 6 ENTITLED BATH USE before placing the bath in service Incorrect handling can damage the bath and void the warranty 4 1 Unpacking Unpack the Micro Bath carefully and inspect it for any damage that may have occurred during shipment If there is shipping damage notify the carrier immediately Verify that the following components are present 7102 Micro Bath Transport Pour Access Lid Probe Basket Stir Bar Power Cord User s Guide Report of Calibration C
56. rily or SET 9 7 Proportional Band In a proportional controller such as this the heater output power is proportional to the well temperature over a limited range of temperatures around the set point This range of temperature is called the proportional band At the bottom of the proportional band the heater output is 100 At the top of the proportional band the heater output is 0 Thus as the 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 well and response time depend on the width of the proportional band If the band is too wide the well temperature will deviate excessively from the set point due to varying external conditions This is because the power output changes very little with temperature and the controller cannot respond very well to changing conditions or noise in the system If the proportional band is too narrow the 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 The proportional band width is set at the factory to about 5 0 C The proportional band width may be altered by the user if he desires to optimize the control characteristics for a particular application 9 7 7102 User s Guide 9 8 The proportional band width
57. sages signify the following problems with the controller Err 1 a RAM error Err 2 a NVRAM error Err 3 a Structure error Err 4 an ADC setup error Err 5 an ADC ready error Err 6 Defective control sensor The control sensor may be shorted open or otherwise damaged Initialize the system by performing the Factory Reset Sequence described above Err 7 Heater control error Initialize the system by performing the Factory Reset Sequence described above The stirrer is not stirring Stirrer speed needs adjusting In the Operating Parameters menu adjust the stirrer speed Str Sp to 0 Wait for the motor to stop Adjust the stirrer speed to a setting greater than 8 but less than or equal to 25 Temperature readout is not the actual Possible RF energy emission With the unit temperature of the well stable slowly rotate the unit If no change occurs the unit may need to be calibrated If the display changes more than twice the normal display deviation another unit in the area could be emitting RF energy Move the unit to a different location and rotate the unit again If the temperature is correct in this new area or deviates differently than the first are RF energy is present in the room If you have to perform the test in the affected area use the comparison test to eliminate any possible errors Instrument is unstable Varying line voltage or fluid is not stirring Place the unit on a clean p
58. se unknown hazards to the user DO NOT use the unit in environments other than those listed in the user s guide Completely unattended operation in not recommended DO NOT install access cover without holes onto a bath that is energized Dangerous pressures may result from fluids vaporizing 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 or safety hazards may arise Inspect the instrument for damage before each use DO NOT use the instrument if it appears damaged or operates abnormally Before You Start 1 2 Safety Information Before initial use or after transport or after storage in humid or semi humid environments or anytime the instrument has not been energized for more than 10 days the instrument needs to be energized for a dry out period of 2 hours before it can be assumed to meet all of the safety requirements of the IEC 61010 1 If the product is wet or has been in a wet environment take necessary measures to remove moisture prior to applying power such as storage in a low humidity temperature chamber operating at 50 C for 4 hours or more The instrument is intended for indoor use only Lift the instrument by the handle provided to move the instrument DO NOT move the instrument until the display reads
59. ta returned to user x Character data returned to user Note When DUPLEX is set to FULL and a command is sent to READ the command is returned followed by a carriage return and linefeed Then the value is returned as indicated in the RETURNED column Chapter 11 Test Probe Calibration Note This procedure is to be considered a general guideline Each laboratory should write their own procedure based on their equipment and their quality program Each procedure should be accompanied by an uncertainty analysis also based on the laboratory s equipment and environment For optimum accuracy and stability allow the calibrator to warm up for 25 minutes after power up and then allow adequate stabilization time after reaching the set point temperature After completing operation of the calibrator allow the well to cool by setting the temperature to 25 C for one half hour before switching the power off 11 1 Calibrating a Single Probe Insert the probe to be calibrated into the well of the bath Best results are obtained with the probe inserted to the full depth of the well Once the probe is inserted into the well allow adequate stabilization time to allow the test probe temperature to settle as described above Once the probe has settled to the temperature of the well it may be compared to the calibrator display temperature The display temperature should be stable to within 0 1 C degree for best results 7102 User s Guide Caution
60. tely begin transmitting temperature readings at the programmed rate The serial communications uses 8 data bits one stop bit and no parity The set point and other commands may be sent via the serial interface to set the temperature set point and view or program the various parameters The interface commands are discussed in Section 10 2 All commands are ASCII character strings terminated with a carriage return character CR ASCII 13 10 10 3 7102 User s Guide 10 4 10 2 Interface Commands The various commands for accessing the calibrator functions via the digital interfaces are listed in this section see Table 5 These commands are used with the RS 232 serial interface The commands are terminated with a carriage return character The interface makes no distinction between upper and lower case letters hence either may be used Commands may be abbreviated to the minimum number of letters which determines a unique command A command may be used to either set a parameter or display a parameter depending on whether or not a value is sent with the command following a character For example e lt CR gt will return the current set point and s 150 0 lt CR gt will set the set point to 150 0 degrees In the following list of commands characters or data within brackets P and 37 H are optional for the command A slash denotes alternate characters or data Numeric data denoted by n may be entered
61. the serial interface menu The serial ei BEES interface parameters menu is outlined in Se ge Figure 7 on page 32 3TXD TE ANC e alt 5 GND oe e e 5 CTS BNC pe 6 DSR HA Zement df 7GND BCTS 8 DCH ANC 20 DIR Figure 8 Serial Cable Wiring To enter the serial parameter programming mode first press EXIT while pressing SET and release to enter the secondary menu Press SET repeatedly until the display reads PAr Press UP until the serial interface menu is indicated with Serial Finally press SET to enter the serial parameter menu In the serial interface parameters menu are the baud rate the sample rate the duplex mode and the linefeed parameter Digital Communication Interface 10 1 Serial Communications 10 1 2 1 Baud Rate The baud rate is the first parameter in the menu The display will prompt with the baud rate parameter by showing bAUd Press SET to choose to set the baud rate The current baud rate value will then be displayed The baud rate of the 7102 serial communications may be programmed to 300 600 1200 2400 4800 or 9600 baud The baud rate is pre programmed to 2400 baud Use UP or DOWN to change the baud rate value Press SET to set the baud rate to the new value or EXIT to abort the operation and skip to the next parameter in the menu 10 1 2 2 Sample Period The sample period is the next parameter in the menu and prompted with SPEr T
62. the setting 2400 b Current baud rate The baud rate of the serial communications may be programmed to 300 600 1200 2400 4800 or 9600 baud Use UP or DOWN to change the baud rate value ene 4800 b l New baud rate Press SET to set the baud rate to the new value or EXIT to abort the operation and skip to the next parameter in the menu 9 8 2 2 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 measurements transmitted from the serial interface If the sample rate is set to 5 the instrument 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 none SPer Flashes SPEr and then displays the setting SPa1 Current sample period seconds Adjust the value with UP or DOWN and then use SET to store the sample rate to the displayed value EXIT does not store the new value 8 SP 60 New sample period 9 8 2 3 Duplex Mode The next parameter is the duplex mode The duplex mode may be set to full duplex or half duplex With full duplex any commands received by the calibrator via the serial interface will be immediately echoed or transmitted back to the device of origin With half duplex the commands will be executed but not e
63. tion of the fluid at higher temperatures may affect temperature stability because of cool condensed fluid dripping into the bath from the lid 8 3 2 Viscosity Viscosity is a measure of the thickness of a fluid how easily it can be poured and mixed Viscosity affects the temperature stability of the bath With low viscosity fluid mixing is better which creates a more uniform temperature throughout the bath This improves the bath response time which allows it to maintain a more constant temperature For good control the viscosity should be less than ten centistokes Twenty centistokes is about the upper limit of allowable viscosity Viscosities greater than this cause very poor control stability and may also overheat or damage the stirring motor With oils viscosity may vary greatly with temperature 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 8 3 3 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 and cooling The proportional band may require some adjustment depending on the specific heat of the fluid 8 3 4 Thermal Conductivity Thermal conductivity measures how easily heat flows through th
64. to operate safely with adequate thermal properties to meet the application requirements Also be aware that some fluids expand and could overflow the bath if not watched Refer to Section 8 3 Bath Fluid and subsequent subsections 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 energized reducing the stress on the system The bath generates extreme temperatures Precautions must be taken to prevent personal injury or damage to objects Probes may be extremely hot or cold when removed from the bath Cautiously handle probes to prevent personal injury 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 inserting it into a hot fluid Be aware that cleaning the probe can be dangerous if the probe has not cooled to room temperature Additionally high temperature fluids may ignite the paper
65. towels if the probe has not been cooled 6 1 7102 User s Guide 6 2 A Warning Some of the high temperature fluids react violently to water or other liquid mediums For optimum accuracy and stability allow the bath adequate stabilization time after reaching the set point temperature 6 2 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 allow 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 calibrate multiple probes is that the probes do not need to be identical in construction 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 totally 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 Scientific we suggest a general rule of thumb for immersion depth to reduce the stem effect to a minimum 15 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 h
66. ty may take 20 to 30 minutes more of stabilization time Chapter 5 Installation Caution READ SECTION 6 ENTITLED BATH USE before placing the bath in service Incorrect handling can damage the bath and void the warranty 5 1 Bath Environment The 7102 Micro Bath is a precision instrument which should be located in an appropriate environment The location should be free of drafts extreme temperatures and temperature changes dirt etc The surface where the bath is placed must be level Because the bath is designed for operation at high temperatures keep all flammable and meltable materials away from the bath Although the bath is well insulated top surfaces do become hot Beware of the danger of accidental fluid spills The bath should be placed on a heat proof surface such as concrete with plenty of clear space around the bath If the bath is operated at high temperatures a fume hood should be used to remove any vapors given off by hot bath fluid 5 2 Dry out Period Before initial use after transport and any time the instrument has not been energized for more than 10 days the bath will need to be energized for a dry out period of 1 2 hours before it can be assumed to meet all of the safety requirements of the IEC 61010 1 5 1 7102 User s Guide 5 3 Bath Preparation and Filling The 7102 Micro Bath is not provided with a fluid Various fluids are available from Hart Scientific and other sources Depend
67. utions 1 2 2 Cautions Cautions To avoid possible damage to the instrument follow these guidelines e Always operate this instrument at room temperatures listed in Section 3 2 Environmental Conditions Allow sufficient air circulation by leaving at least 6 inches 15 cm of clearance around the instrument e Overhead clearance is required DO NOT place this instrument under a cabinet or other structure e Never introduce any foreign material into the well e DO NOT change the values of the calibration constants from the factory set values The correct setting of these parameters is important to the safety and proper operation of the unit e DO NOT slam the probe stems into the well This type of action can cause a shock to the sensor and affect the calibration e DO use a ground fault interrupt device 1 4 Before You Start 1 3 Authorized Service Centers e DO NOT operate this instrument in an excessively wet oily dusty or dirty environment e The unit is a precision instrument Although it has been designed for optimum durability and trouble free operation it must be handled with care e Most probes have handle temperature limits Be sure that the probe handle temperature limit is not exceeded in the air above the instrument e The instrument and any thermometer probes used with it are sensitive instruments that can be easily damaged Always handle these devices with care Do not allow them to be dropped

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