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7320 Users Guide 4A2..

1. Duplex Mode 7 A m T J SET EXIT y T ined Secondary Functions mperatur emperature SET EXIT ER SET v OE 4 il EXIT Display Power v C I ExT Reset Cutout SET i SET l Y j Cutout Active X EXIT Set Proportional Band zd I SET lt EXIT Select Setpoint ser Temp SET lt EXIT Set LET Temp SET a EXIT Adjust Setpoint I SET Y lt Adjust Vernier EXIT I SET Y 4 1 EXIT Set Scale C F Configuration Menu 4 SET SET EXIT EXIT i EXIT EXIT prove Operating w gt serial u L IEEE 488 LE Menu Down Parameters Interface DOWN Interface lt Menu lt Menu c SET SET SET 5 Y Y id Y
2. SCIENTIFIC Fluke Company 000 7320 Calibration Bath User s Guide Rev 4 2101 Hart Scientific 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 www hartscientific com Subject to change without notice Copyright 2004 Printed in USA Rev 4 2101 Table of Contents 1 Before You Statt oc ee ew Rom ee 1 14 Symbols Used a sma mac ouo oe bo x A 1 12 2 1 2 1 Warnings ea wae l Se ee eS Baie be e Ee 2 1 2 2 e DI 4 L3 Hart Scientific Authorized Service Centers 5 2 9 3 Specifications and Environmental Conditions 11 3 1 SpecMicatlons 22 55 2 eedem RR mE a 11 3 2 Environmental Conditions 12 Ji Wanay 2 2542 reso ELE I BER US ae 12 4 Quick 15 4 Unpacking 15 42 Setup ao basne eka roh 15 4 5 2 vce eee 16 44 Setting the Temperature 16 5 T stallation e sc w saca 885 4 19 5 1 Bath Environment 19 5 2 Dry out Period 19 5 3 Bath PreparationandFillng 19 5 31 D
3. 30 51102 Mineraloil sui s i uo UR x oe ee Ee ee ERS DOR OR OR 30 86 L10 5 Silicone Ol ow ek a o xem d 31 8 1 11 Fluid Characteristics 31 8 1111 limitations and Disclaimer sx 0004 os Rok RO RR Rom om SLL About Graph sus a Lok rc 5555 31 G A SUMING s or RUN 34 8 3 5 2 2 5 hE ORO 34 94 Heater ok 00 pan ek pea Bf ae ee ME 34 85 Temperature 35 86 Reingeration s aces ue SERE ee a 35 9 Controller 371 91 Bath Temperature 37 92 37 9 3 Temperature 39 9 3 1 Programmable Set points 39 9 3 2 Setpoint Values XX Oe LEGE RR UR 40 9 3 3 set point Vernier es soe or o o p 40 9 4 Temperature Scale Units 41 9 5 Secondary 42 96 Heater x X EROS 42 97 Proportional Band 42 9 8 Cutout oro m e Ra 44 9 9 Controller Configuration 45 910 Probe 45 GAOT RO iy
4. e Heat transfer medium lifetime is dependent upon the type of medium and the conditions of use The fluid should be checked at least every month for the first year and regularly thereafter This fluid check pro vides a baseline for knowledge of bath operation with clean usable fluid Once some fluids have become compromised the break down can occur rapidly Particular attention should be paid to the viscosity of the fluid A significant change in the viscosity can indicate that the fluid is contaminated being used outside of its temperature limits con tains ice particles or is close to a chemical breakdown Once data has been gathered a specific maintenance schedule can be outlined for the instrument Refer to Section 8 General Operation for more infor mation about the different types of fluids used in calibration baths e Depending on the cleanliness of the environment the internal parts parts behind the front cover only of the cold bath should be cleaned and or checked at least every six months for dust and dirt Particular attention should be paid to the condensing coil fins The fins should be vacuumed or brushed free of dust and dirt on a regular basis Dust and dirt inhibit the operation of the condensing coil and thus compromise the performance and lifetime of the cooling system To clean or check the internal parts remove the four screws on the fornt panel display Remove the two screws under the front panel on the left a
5. 1010 2 010 EN 61010 2 010 standards 71
6. The displayed process tem perature is in error and the controller remains in the cooling or the heating state at any set point value Possible causes may be either a faulty control probe or er roneous data in memory The probe may be disconnected burned out or shorted Check that the probe is connected properly The probe may be checked with an ohmmeter to See if it is open or shorted The probe is a platinum 4 wire Din 43760 type therefore the resistance should read 0 2 to 2 0 ohms between pins 1 and 2 on the probe connector and 0 2 to 2 0 ohms between pins 3 and 4 The resistance should read from 100 to 300 ohms be tween pins 1 and 4 depending on the temperature If the probe is defective contact a Hart Scientific Authorized Service Center for assistance If the problem is not the probe erroneous data in memory may be the cause Re initialize the memory as discussed in the problem display flashes cutout and an incor rect process temperature If the problem remains the cause may be a defective electronic component contact a Hart Scientific Authorized Service Center see Section 1 3 for assistance The controller controls or attempts to control at an in accurate temperature The controller operates normally except when controlling at a specified set point At this set point the temperature does not agree with that measured by the user s refer ence thermometer to within the specified accuracy This proble
7. Setting the bath temperature involves three steps 1 selecting the set point memory 2 adjusting the set point value and 3 adjusting the vernier if desired Programmable Set points The controller stores 8 set point temperatures in memory The set points can be quickly recalled to conveniently set the bath to a previously pro grammed temperature set point To set the bath temperature one must first select the set point memory This function is accessed from the temperature display function by pressing SET The number of the set point memory currently being used is shown at the left on the display followed by the current set point value 25 00 Bath temperature in degrees Celsius i 25 0 Set point memory 1 25 0 C currently used To change the set point memory press UP or DOWN Increment memory 40 0 New set point memory 4 40 0 39 7320 User s Guide 40 9 3 2 9 3 3 Press SET to accept the new selection and access the set point value SET Accept selected set point memory Set point Value The set point value may be adjusted after selecting the set point memory and pressing SET The set point value is displayed with the units C or F at the left 48 00 Set point 4 value If the set point value need not be changed then press EXIT to resume dis playing the bath temperature Press UP or DOWN to adjust the set point value Inc
8. 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 CTO Parameter CTO sets the calibration of the over temperature cutout This is not adjustable by software but is adjusted with an internal potentiometer For the 7320 bath this parameter should read 160 BO and BG 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 im proved accuracy then calibrate RO and ALPHA according to the procedure given in Section 11 Calibration Procedure L These parameters set the upper and lower set point limits of the bath DO NOT change the values of these parameters from the factory set values To do so may present danger of the bath exceeding its temperature range causing damage or fire 10 Digital Communication Interface 10 10 1 10 1 1 Digital Communication Interface The 7320 bath is capable of communicating with and being controlled by other equipment through the digital interface Two types of digital interface are available the RS 232 serial interface which is standard and the IEEE 488 GPIB interface which is optional With a digital interface the bat
9. perature especially with oils When using fluids with higher viscosities the controller proportional band may need to be increased to compensate for the reduced response time Otherwise the temperature may begin to oscillate Specific Heat Specific heat is the measure of the heat storage ability of the fluid Specific heat to a small degree affects the control stability It also affects the heat ing and cooling rates Generally a lower specific heat means quicker heat 27 7320 User s Guide 28 8 1 4 8 1 5 ing and cooling The proportional band may require some adjustment depending on the specific heat of the fluid Thermal Conductivity Thermal conductivity measures how easily heat flows through the fluid Thermal conductivity of the fluid affects the control stability temperature uniformity and temperature settling time Fluids with higher conductivity distribute heat more quickly and evenly improving bath performance Thermal Expansion Thermal expansion describes how much the volume of the fluid changes with temperature Thermal expansion of the fluid must be considered since the increase in fluid volume as the bath temperature increases may cause overflow It may be dangerous to permit the fluid to overflow the tank It may also cause loss of valuable bath fluid Excessive thermal expansion may also be undesirable in applications where constant liquid level is important Thermal expansion coefficients of s
10. After evacuation charge the system with approximately 160 grams of R 507 With the compressor running and the bath operating at 25 C verify that the suction pressure is 17 18 psi 63 Maintenance 13 Maintenance 13 1 General e battery is used to maintain operating parameters in the unit op erating parameters including calibration parameters should be checked on a regular basis to insure accuracy and proper operation of the instrument See the troubleshooting section for the procedure on checking the status of the battery e The calibration instrument has been designed with the utmost care Ease of operation and simplicity of maintenance have been a central theme in the product development Therefore with proper care the in strument should require very little maintenance Avoid operating the instrument in dirty or dusty environments e If the outside of the bath becomes soiled it may be wiped clean with a damp cloth and mild detergent Do not use harsh chemicals on the sur face which may damage the paint e Periodically check the fluid level in the bath to ensure that the level has not dropped drop in the fluid level affects the stability of the bath Changes in fluid level are dependent upon several factors spe cific to the conditions in which the equipment is used A schedule can not be outlined to meet each set of conditions Therefore the bath should be checked weekly and adjustments made as required
11. C fl oc 10 104 C 0 386 25 C 150 C 100 C 0 433 200 C Dow Corning 710 80 C v 302 C fl oc 302 C 50 80 C 1 11 25 C 0 363 40 0 00035 0 00077 00 25 C 7 204 C 0 454 25 C 150 C 5017 100 C 0 505 200 C Dow Corning 66 C 315 C fl oc 315 C 50 66 C 0 96 25 C 0 34 0 0003 0 00095 00 25 C 210 H 14 204 C 100 C 150 C Silicone Oil Heat Transfer 145 C fr 530 C NONE 34 150 C 2 0 150 C 0 33 0 0014 0 00041 1 6 5 300 19 2 300 5001 2 4 500 1 7 500 32 Limiting Factors b boiling point viscosity Flash point test oc open cup Very low water solubility ice will form as a slush from condensation below freezing e high evaporation cc closed cup fl flash point fr freeze point v Viscosity Points shown are at 50 and 10 centistokes viscosity When vis cosity is greater than 50 centistokes stirring is very poor and the fluid is un satisfactory for bath applications Optimum stirring generally occurs at 10 centistokes and below General Operation 100 C 0 Silicone Oil 5017 Silicone Oil 5014 Silicone Oil 5013 Silicone Oil 5012 Silicone Oil 5010 7500 5023 Halocarbon 5019 Mineral Oil 5011 Water Methanol Ethanol Ethylene Glycol 50 50 with H20 5020 Dynalene HF LO 5022 Bath Salt 5001 100 C 200 C 300 C 400 C 500
12. Cutout BAUD Devi m Reset Mode me E SET EXIT SET EXIT SET EXIT EXIT gt EXIT i H Adj Cutout L E I i I 0 SET EXIT H SET EXIT Y Sample i 1 ALPHA IEEE 488 7 SET EXIT gt SET EXIT Option Installed EXIT SENS re E B 5 E SET EXIT z o E o 2 Figure 5 Controller Operation Flowchart 38 Linefeed 1 Cd e J EXIT 9 Controller Operation 9 3 9 3 1 rESEE P Cutout reset function Press SET once more to reset the cutout Reset cutout This will also switch the display to the set temperature function To return to displaying the temperature press the EXIT button If the cutout is still in the over temperature fault condition the display will continue to flash cut out The bath temperature must drop a few degrees below the cutout set point before the cutout can be reset Temperature Set point The bath temperature can be set to any value within the range and with resolution as given in the specifications The operator must know the tem perature range of the particular fluid used in the bath and the bath should only be operated well below the upper temperature limit of the liquid In addition the cutout temperature should also be set below the upper limit of the fluid
13. 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 liq uid 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 im mersion depth to reduce the stem effect to a minimum 20 x the diameter of the UUT the sensor length Do not submerge the probe handles If the probe handles get too warm during calibration at high temperatures a heat shield could be used just below the probe handle This heat shield could be as simple as aluminum foil slid over the probe before inserting it in the bath or as complicated as a specially designed reflective metal apparatus When calibrating over a wide temperature range starting at the highest temperature and progressing down to the lowest temperature can generally achieve better results Probes can be held in place in the bath by using probe clamps or drilling holes in the access cover Other fixtures to hold the probes can be designed The 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 stabil ity 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 c
14. 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 mail xingye han fluke com cn Fluke South East Asia Pte Ltd Fluke ASEAN Regional Office Service Center 83 Clemenceau Avenue 15 15 06 Ue Square 239920 SINGAPORE Phone 465 731 2922 Telefax 65 737 5155 E mail antng singa fluke com When contacting these Service Centers for support please have the follow ing information available e Model Number 1 Before You Start e Serial Number e Voltage e Complete description of the problem 2 Introduction Introduction The Hart Scientific Model 7320 is a bench top constant temperature bath useful in temperature calibration and other applications requiring stable temperatures An innovative state of the art solid state temperature control ler has been incorporated which maintains the bath temperature with ex treme stability The temperature controller uses a micro controller to execute the many operating functions User interface is provided by the 8 digit LED display and four key switches Digital remote communications is standard with an RS 232 and optional with an IEEE 488 interface
15. If the cutout activates when the bath temperature is well below the cutout set point or the cutout does not reset when the bath temperature drops and it is manually re set then the cutout circuitry or the cutout thermocouple sensor may be faulty or disconnected Contact a Hart Au thorized Service Center see Section 1 3 for assistance The display flashes cutout and an incorrect process temperature The problem may be that the controller s voltmeter circuit is not functioning properly A problem could exist with the memory back up battery If the battery voltage is insuffi cient to maintain the memory data may become scram bled causing problems A nearby large static discharge may also affect data in memory Holding the SET and EXIT keys down while power to the controller is switched on may reset the memory The display shows init indicating the memory is being initialized At this point each of the controller parameters and calibration constants must be reprogrammed into memory You can obtain the calibration constants from Report of Test If the problem reoccurs the battery should be replaced Contact a Hart Authorized Service Center see Section 1 3 for assistance If initializing the memory does not remedy the problem there may be a failed electronic component Contact a Hart Authorized Service Center see Section 1 3 for assistance 14 Troubleshooting Problem Causes and Solutions
16. Note When checking the over temperature cutout be sure that the temperature limits of the bath fluid are not exceeded Exceeding the temperature limits of the bath fluid could cause harm to the operator lab and instrument 14 Troubleshooting 14 14 1 Troubleshooting This section contains information on troubleshooting CE Comments and a wiring diagram This information pertains to a number of bath models and certain specifics may not pertain to your model Troubleshooting In the event that the instrument appears to function abnormally this section may help to find and solve the problem Several possible problem condi tions are described along with likely causes and solutions If a problem arises please read this section carefully and attempt to understand and solve the problem If the probe seems faulty or the problem cannot other wise be solved contact a Hart Scientific Authorized Service Center see Sec tion 1 3 for assistance Be sure to have the model number and serial number of your instrument available Problem Causes and Solutions The heater indicator LED The display does not show cutout nor displays an incor stays red but the tempera bath temperature but the controller otherwise ap ture does not increase pears to operate normally The problem may be either insufficient heating or no heating at all or too much cool ing The heater power setting being too low especially at higher operating
17. a bath situation The open cup flash point is measured under the condition of vapors escap ing the tank The closed cup flash point is measured with the vapors being contained within the tank Since oxygen and an ignition source is less available inside the tank the closed cup flash point will be lower than the open cup flash point 29 7320 User s Guide 30 8 1 9 8 1 10 8 1 10 1 8 1 10 2 8 1 10 3 Environmentally hazardous fluids require special disposal according to ap plicable federal or local laws after use Cost Cost of bath fluids may vary greatly from cents per gallon for water to hun dreds of dollars per gallon for synthetic oils Cost may be an important con sideration when choosing a fluid Commonly Used Fluids Below is a description of some of the more commonly used fluids and their characteristics Water Water is often used because of its very low cost its availability and its ex cellent temperature control characteristics Water has very low viscosity and good thermal conductivity and heat capacity which make it among the best fluids for good control stability at lower temperatures Temperature stability is much poorer at higher temperatures because water condenses on the lid cools and drips into the bath Water is safe and relatively inert The electri cal conductivity of water may prevent its use in some applications Water has a limited temperature range from a few degrees above 0 C to
18. a few de grees below 100 C At higher temperatures evaporation becomes signifi cant Water used in the bath should be distilled or deionized to prevent mineral deposits Consider using an algicide chemical in the water to pre vent contamination Ethylene Glycol The temperature range of water may be extended by using a solution of one part water and one part ethylene glycol antifreeze The characteristics of the ethylene glycol water solution are similar to water but with higher vis cosity Use caution with ethylene glycol since this fluid is very toxic Ethyl ene glycol must be disposed of properly Mineral Oil Mineral oil or paraffin oil is often used at moderate temperatures above the range of water Mineral oil is relatively inexpensive At lower temperatures mineral oil is quite viscous and control may be poor At higher temperatures vapor emission becomes significant The vapors may be dangerous and a fume hood should be used As with most oils mineral oil will expand as temperature increases so be careful not to fill the bath too full that it over flows 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 General Operation 8 1 10 4 8 1 11 8 1 11 1 8 1 11 2 Silicone Oil
19. atte cg tale oe 46 9 10 0 46 911 Operating Parameters 2 46 9 11 1 Cutout Reset 46 9 12 1 47 932 3 BAUDA o exo Rena zo 41 912 2 SamplePeriod a e d a oe 41 9143 Duplex Modes Dn Gr PS ale 48 912 4 lidnefeed 22k XR xem a a X x o3 48 913 IEEE 488 Parameters 49 9131 IEEE 488 49 9 13 2 Transmission 49 914 Calibration 50 ahs es 50 91342 BONG BG s 6 RE 50 9143 e Ra s 50 10 Digital Communication 51 101 Serial 51 ed ee es 51 10490 ap 52 10 1 2 1 BAUD Rates arr BAe oe E det RP xe ME 52 10 72 22 Sample Period 2 5 hin don lee m hee eu eom m mra 53 1012 3 Duplex 53 10124 Limefeed noctu exer 53
20. bath fluid The stirring motor is mounted on the bath tank lid It drives the stirring propeller to provide mixing of the bath fluid Proper mixing of the fluid is important for good constant temperature stability On the bath lid is a large access hole This is used for filling and emp tying the bath with fluids and placement of thermometers and devices into the bath When possible the access hole should be covered An access hole cover should be used to cover the access opening in the top of the bath This improves bath temperature stability prevents excess fluid evaporation or fumes and increases safety with hot fluid The user may drill or cut holes in the cover to accommodate the instru ments to be calibrated or immersed in the bath Spare covers are avail able from Hart Scientific Back Panel On the back of the bath are the system fuses removable power cord high low voltage indicator drain serial port and IEEE 488 port if installed General Operation 8 1 1 8 1 2 8 1 3 General Operation Heat Transfer Fluid Many fluids will work with 7320 bath Choosing a fluid requires consider ation of many important characteristics of the fluid Among these are tem perature range viscosity specific heat thermal conductivity thermal expansion electrical resistivity fluid lifetime safety and cost Temperature Range One of the most important characteristics to consider is the temperature range of the fluid
21. if the bath 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 bath temperature is With good control stability the percent heating power should not fluctuate more than 1 within one minute The heater power display is accessed in the secondary menu Press SET and EXIT simultaneously and release The heater power will be displayed as a percentage of full power Access heater power in secondary menu Pct Heater power in percent To exit out of the secondary menu press EXIT To continue on to the pro portional band setting function press SET Return to temperature display Proportional Band In a proportional controller such as this the heater output power is propor tional to the bath temperature over a limited range of temperatures around the set point This range of temperature is called the proportional band At the bottom of the proportional band the heater output is 100 At the top of the proportional band the heater output is O Thus as the bath temperature rises the heater power is reduced which consequently tends to lower the temperature back down In this way the temperature is maintained at a fairly constant temperature The temperature stability of the bath depends on the width of the propor tional band see Figure 6 If the band is too wide the bath temperature de viates excessively fr
22. point and an 5 50 00 cr sets the set point to 50 00 degrees In the following list of commands characters or data within brackets and are optional for the command A slash denotes alternate char acters or data Numeric data denoted by n may be entered in decimal or 10 Digital Communication Interface Table 3 Interface Command Summary Command Command Returned Acceptable Command Description Format Example Returned Example Values Display Temperature Read current set point s etpoint 8 set 9999 99 C or set 150 00 Set current set point ton s etpoint n s 450 Instrument Range Read vernier v ernier v 9 99999 v 0 00000 Set vernier to n v ernier n v 00001 Depends on Configuration Read temperature t emperature t t 9999 99 C or F t 55 69C Read temperature units u nits u u X Set temperature units u nits c f CorF Set temperature units to u nits c u C Celsius Set temperature units to u nits f u Fahrenheit Secondary Menu Read proportional band pr op band pr pr 999 9 pr 15 9 setting Set proportional band ton pr op band n pr 8 83 Depends on Configuration Read cutout setting c utout c 9999 x xxx c 620 C in Set cutout setting c utout n r eset Set cutout to n degrees c utout n c 500 Temperature Range Reset cutout now c utout r eset c r Read hea
23. the installation instructions above 20 Tank Baffle Showing Minimum and Maximum FillLevels 21 Front s i xx sleid ge mem one aon SUR AUR 25 Chart Of Various Bath Fluids And Their Properties 33 Controller Operation 10 38 Bath Temperature Fluctuation At Various Proportional Band Settings 43 Serial Communications Cable 52 Calibration 61 Tables Table 1 Table 2 Table 3 Table 3 Table 3 International Electrical Synbols 1 Table Of Various Bath Fluids And Their Properties 32 Interface Command 55 Interface Command Summary 56 Interface Command Summary Continued 51 1 Before You Start 1 1 Before You Start Symbols Used Table 1 lists the International Electrical Symbols Some or all of these sym bols may be used on the instrument or in this manual Table 1 International Electrical Symbols Symbol Description No AC Alternating Current v AC DC Battery CN MA Complies with European Union Directives DC Double Insulated Electric Shock Fuse PE Ground Hot Surface Burn Hazard Read the User s Manual Important Information Off On 7320 User s Guide 1 2 1
24. times power has been ap plied to the bath Also briefly displayed is data which indicates the control ler hardware configuration This data is used in some circumstances for diagnostic purposes Heater The temperature controller precisely controls the bath heater to maintain a constant bath temperature Power is controlled by periodically switching the heater on for a certain amount of time using a solid state relay The front panel red green control indicator shows the state of the heater The control indicator glows red when the heater is on and glows green when the heater is off The indicator will pulse constantly when the bath is maintaining a stable temperature General Operation 8 5 8 6 Temperature Controller Hart Scientific s unique hybrid digital analog temperature controller controls the bath temperature 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 passed to a pulse width modulator cir cuit which controls the amount of power applied to the bath heater The bath is operable within the temperature range given in the specifications For protection against solid state relay failure or other circuit failure the mi cro co
25. 10 1 3 Serial Operation 524 UR 53 10 2 488 Communication 53 10 21 Be 54 10 211 1 488 54 10 2 42 Transmission 54 10 2 2 488 Operation gt lt e ca s ssd ae ot kx E RS 54 10 3 Interface 54 10 4 Cooling 57 11 Calibration Procedure 59 111 Calibration 59 11 2 Measuring the Set point 59 11 3 Computing RO and 60 114 Calibration Example 60 12 Charging Instructions 63 121 52404554 ed 63 12 2 63 1223 Charging 93 939m RR no RS 63 13 65 ISI Generdb ona nu ISSUED MA Mig e ae ee 65 lii 14 Troubleshooting c l nnn 61 14 1 Troubleshooting 14 2 Comments 10 14 2 1 Directive 14 2 2 Low Voltage Directive Safety Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Drain Valve Installation IMPORTANT Do Not Over Tighten Follow
26. 2 1 Symbol Description 6 Canadian Standards Association Us 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 energy con suming equipment to be supplied from the fixed installation Exam ples include household office and laboratory appliances C TIC Australian Mark CAT II Safety Information Use this instrument only as specified in this manual Otherwise the protec tion provided by the instrument may be impaired The following definitions apply to the terms Warning and Caution e Warning identifies conditions and actions that may pose hazards to the user e Caution identifies conditions and actions that may damage the in strument being used A Warnings To avoid personal injury follow these guidelines GENERAL DO NOT use the instrument for any application other than calibration work The instrument was designed for temperature calibration Any other use of the unit may cause unknown hazards to the user e DONOT use the unit in environments other than those listed in the user s guide DO NOT overfill the bath Overflowing extremely cold or hot fluid may be harmful to the operator See Section 5 3 Bath Preparation and Fill ing for specific instructions e Follow all safety guidelines listed in the user s manual e Calibration Equipment shou
27. 9 ter ton 999 9 Read BG calibration bg bg bg 999 99 bg 156 25 parameter Set BG calibration parameter bg n bg 156 25 999 9 to ton 999 9 Read low set point limit tllow 1 tl 999 tl 80 value Set low set point limit ton tl ow n tl 80 999 9 to 999 9 Read high set point limit th igh th th 999 th 205 value Set high set point limit to th igh n th 205 999 9 to 999 9 Miscellaneous not on menus Read firmware version ver sion ver ver 9999 9 99 ver 7025 3 5 number 6 56 10 Digital Communication Interface Interface Command Summary Continued Command Command Returned Acceptable Command Description Format Example Returned Example Values Read structure of all h elp h list of commands commands Set Refrigeration 2 1 0 Oor 1 Set Refrigeration to on f2 n f2 1 Set Refrigeration to off f2 n 2 0 Legend Note 10 4 Optional Command data Returns either information n Numeric data supplied by user 9 Numeric data returned to user x Character data returned to user When DUPLEX is set to FULL and a command is sent to READ the command is re turned followed by a carriage return and linefeed Then the value is returned as indi cated in the RETURNED column 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 t
28. C 600 C FL 302 C FL 280 C FL 232 C FL 211 C FL 133 C FR Pure 12 FL 16 C 106 BP FL 60 C Legend Shaded area represents usable range of fluid starting at 50 centistokes Lighter shading represents decreasing viscosity while vaporization and decomposition increase Black area represents liquid range with excessive viscosity Range over which a fume hood is recommended Figure 4 Chart Of Various Bath Fluids And Their Properties Decomposition m BP Boiling Point CS Centistokes EP Evaporation Point fluid loss due to evaporation FL Flash Point FR Freeze Point PP Pour Point Fume Point The point at which a fume hood should be used This point is very subjective in nature and is impacted by individual tolerance to different fumes and smells how well the bath is covered the surface area of the fluid in the bath the size and ventilation of the facility where the bath is located and 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 discus sion in Section 8 1 8 Safety 33 7320 User s Guide 34 8 2 8 3 8 4 Boiling Point At or n
29. Few fluids work well throughout the entire temperature range of the bath The temperature at which the bath is operated must al ways be within the safe and useful temperature range of the fluid used The lower temperature range of the fluid is determined either by the freeze point of the fluid or the temperature at which the viscosity becomes too great The upper temperature is usually limited by vaporization flammability or chemical breakdown of the fluid Vaporization of the fluid at higher temperatures may adversely affect temperature stability because of cool condensed fluid dripping into the bath from the lid The bath temperature should be limited by setting the safety cutout so that the bath temperature cannot exceed the safe operating temperature limit of the fluid Viscosity Viscosity is a measure of the thickness of a fluid or how easily it can be poured and mixed Viscosity affects the temperature uniformity and stability of the bath With lower viscosity fluid mixing is better creating a more uni form temperature throughout the bath This improves the bath response time allowing it to maintain a more constant temperature For good control the viscosity should be less than 10 centistokes 50 centistokes is about the practical upper limit of allowable viscosity Viscosity greater than this causes very poor control stability because of poor stirring and may also overheat or damage the stirring motor Viscosity may vary greatly with tem
30. 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 Fluid Characteristics Charts Table 2 and Figure 4 on pages 32 and 33 have been created to provide help in selecting a heat exchange fluid media for your constant temperature bath These charts provide both a visual and numerical representation of most of the physical qualities important in making a selection The list is not all inclusive There may be other useful fluids not shown in this listing The charts include information on a variety of fluids which are often used as heat transfer fluid in baths Because of the temperature range some fluids may not be useful with your bath Limitations and Disclaimer The information given in this manual regarding fluids is intended only to be used as a general guide in choosing a fluid Though every effort has been made to provide correct information we cannot guarantee accuracy of data or assure suitability of a fluid for a particular application Specifications may change and sources sometimes offer differing information Hart Scientific cannot be liable for any personal injury or da
31. The 7320 bath was designed to be compact and low cost without compro mising performance The 7320 bath operates over a wide temperature range from 20 C to 150 C The refrigeration permits sub ambient tempera ture control Specifications and Environmental Conditions 3 1 Specifications and Environmental Conditions Specifications Range 20 C to 150 C Stability 2 sigma 0 005 C at 20 C ethanol 0 005 C at 25 C water 0 007 C at 150 C silicone oil 5012 Uniformity 0 005 C at 20 C ethanol 0 005 C at 25 C water 0 010 C at 150 C silicone oil 5012 Heating Time 80 minutes from 25 C to 150 C silicone oil 5012 Cooling Time 100 minutes from 25 C to 20 C silicone oil 5012 Stabilization Time 15 20 minutes Temperature Setting Digital display with push button entry Set point Resolution 0 01 0 00018 in high resolution Display Temperature 0 01 Resolution Digital Setting Accuracy 0 5 C Digital Setting 0 01 C Repeatability Heater 650 Watts Access Opening 6 8 x 3 7 172mm x 94mm Depth 9 25 234 mm Wetted Parts 304 Stainless Steel Power 115 VAC 10 60 Hz 15 amps 230 VAC 10 50 Hz 8 amps optional 1100 W Note If the voltage is outside 10 the compressor may be damaged Check the back panel label for the cor rect voltage and frequency prior to energizing th
32. The current sample period value will be displayed SA j Current sample period seconds Adjust the value with UP or DOWN and then use SET to set the sample rate to the displayed value SA 60 New sample period pEETEIETEEES 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 bath via the serial interface are immediately echoed or transmitted back to the device of origin With half duplex the commands are executed but not ech oed The duplex mode parameter is indicated by 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 param eter is indicated by pend D AAA B A 9 Controller Operation 9 13 9 13 1 9 13 2 IEEE 488 Parameters Baths may optionally be fitted with an IEEE 488 GPIB interface In this case the user may set the interface address and the transmission termination character within the IEEE 488 parameter menu This menu does not appear on baths not fitted with the interface The menu is indicated by IEEE IEEE 488 parameters menu prn Press SET to enter the menu IEEE 488 Address The IEEE 488 interface must be configured
33. The mode may be changed using UP or DOWN and pressing SET Serial Operation Once the cable has been attached and the interface set up properly the con troller will immediately begin transmitting temperature readings at the pro grammed rate The set point and other commands may be sent to the bath via the serial interface to set the bath and view or program the various pa rameters The interface commands are discussed in Section 10 3 Interface Commands IEEE 488 Communication optional The IEEE 488 interface is available as an option Baths supplied with this option may be connected to a GPIB type communication bus which allows many instruments to be connected and controlled simultaneously To elimi nate noise the GPIB cable should be shielded 5S8 7320 User s Guide 54 10 2 1 10 2 1 1 10 2 1 2 10 2 2 10 3 Setup To use the IEEE 488 interface connect an IEEE 488 standard cable to the back of the bath set the device address and set the transmission termina tion character To enter the IEEE 488 parameter programming menu press EXIT and SET simultaneously and then release to enter the secondary menu Press SET repeatedly until the display reaches 0b E Press UP repeatedly until the IEEE 488 interface menu is indicated with IEEE Press SET to enter the IEEE 488 parameter menu IEEE 488 Address The IEEE 488 address is prompted with A d d r E55 Press SET to pro gr
34. WN Used to decrement the displayed value of parameters UP Used to increment the displayed value EXIT Used to exit from a menu When EXIT is pressed any changes made to the displayed value will be ignored 3 The on off switch controls power to the entire bath including the stirring motor 4 The control indicator is a two color light emitting diode LED This indi cator lets the user visually see the ratio of heating to cooling When the in dicator is red the heater is on and when it is green the heater is off and the bath is cooling 25 7320 User s Guide 26 7 2 7 3 5 The cooling switch turns on the refrigeration for control below 50 and rapid cool down Bath Tank and Lid The bath tank and lid assembly includes the tank the control probe the stirring motor the access hole and the access hole cover The stirring motor cover covers the stirring motor cooling fan and control probe The bath tank is constructed of stainless steel It is very resistant to ox idation in the presence of most chemicals and over a wide range of temperatures The control probe provides the temperature feedback signal to the controller allowing the controller to maintain a constant temperature The control probe is a precision platinum resistance thermometer PRT It is delicate and must be handled carefully The probe is placed in the small hole in the top of the bath so that the probe tip is fully im mersed in the
35. al g C cl s aqn CO 100 Halocarbon 0 8 90 C v 70 NONE 5 7 50 C 1 71 40 0 2 0 0004 0 0011 5019 0 8 40 0 5 70 Methanol 96 C fr 60 C b 54 C 13 35 C 0 810 0 C 0 6 0 0005 0 0014 0 66 0 C 0 792 20 C 20 C 25 0 45 20 Water O C fr 95 C b NONE 1 25 C 1 00 1 00 0 0014 0 0002 0 4 75 C 25 C Ethylene 35 fr 110 C b NONE 7 O C 1 05 0 8 0 C 0 001 Glycol 50 2 50 C 5020 0 7 100 C Mineral Oil 40 C 190 C fl 190 C 15 75 C 0 87 25 0 48 25 C 0 00025 0 0007 5 25 C 5 125 C 0 84 75 C 0 53 75 25 C 50 C 0 81 125 C 0 57 125 C Dow Corning 40 C v 133 C fl 133 C 5 25 C 0 92 25 C 0 4 0 00028 0 00105 000 25 C 200 5 25 C 0 150 C Silicone Oil Dow Corning 359 v 165 C fl cc 165 C 10 25 C 0 934 25 C 0 43 40 C 0 00032 0 0 00108 000 25 C 200 10 3 135 C 0 45 10092 25 C 50 150 C 5012 0 482 200 C Dow Corning 7 v 230 C fl cc 230 C 20 25 C 0 949 9 25 0 370 40 C 0 00034 0 00107 000 25 C 200 20 0 393 25 C 50 150 C 5013 100 C 0 420 200 C Dow Corning 25 C 280 C fl cc 280 C 50 25 C 0 96 25 C 04 0 00037 0 00104 000 25 200 50 25 50 150 Silicone Oil Dow Corning 550 70 C v 232 C fl cc 232 C 50 Q 70 C 107 25 0 358 40 0 00035 0 00075 00 25 C 5016 300
36. alibrated the UUT in the bath working area as close as feasibly possible to the reference probe Calibration of Multiple Probes Fully loading the bath with probes increases the time required for the tem perature to stabilize after inserting the probes Using the reference probe as the guide ensures that the temperature has stabilized before starting the calibration 7 Parts and Controls Parts and Controls Front Panel The following controls and indicators are present on the controller front panel see Figure 3 below 1 the digital LED display 2 the control but tons 3 the bath on off power switch 4 the control indicator light and 5 the cooling on off switch HART 7320 Fluke Company P1 COOLING POWER H H MODE SET DOWN UP EXIT Figure 3 Front Panel 1 The digital display is an important part of the temperature controller It displays the set point temperature and bath temperature as well as the var ious other bath functions settings and constants The display shows tem peratures according to the selected scale units or F 2 The control buttons SET DOWN UP and EXIT are used to set the bath temperature set point access and set other operating parameters and ac cess and set bath calibration parameters brief description of the functions of the buttons follows SET Used to display the next parameter in a menu and to set parameters to the displayed value DO
37. am the address The default address is 22 Change the device address of the bath if necessary to match the address used by the communication equipment by pressing UP or DOWN and then SET Transmission Termination The IEEE 488 transmission termination is prompted with E 0 5 Press SET to access the termination character The present setting is displayed Press UP or DOWN to change the setting Press SET to save the new selection IEEE 488 Operation Commands may now be sent via the IEEE 488 interface to read or set the temperature or access other controller functions All commands are ASCIT character strings and are terminated with a carriage return CR ASCII 13 Interface commands are listed below Interface Commands The various commands for accessing the bath controller functions via the digital interfaces are listed in this section see Table 4 These commands are used with both the RS 232 serial interface and the IEEE 488 GPIB in terface In either case 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 com mand may be used to either set a parameter or display a parameter depend ing on whether or not a value is sent with the command following a character For example an s cr returns the current set
38. cale units of the controller may be set by the user to de grees Celsius or Fahrenheit F The units will be used in displaying the bath temperature set point vernier proportional band and cutout set point The temperature scale units selection is accessed after the vernier adjust ment function by pressing SET From the temperature display function ac cess the units selection by pressing SET 4 times 05 00 Bath temperature Scale units currently selected Press UP or DOWN to change the units Change units New units selected Press SET to accept the new selection and resume displaying the bath temperature Set the new units and resume temperature display 41 7320 User s Guide 42 9 5 9 6 9 7 Secondary Menu Functions which are used less often are accessed within the secondary menu The secondary menu is accessed by pressing SET and EXIT simul taneously and then releasing The first function in the secondary menu is the heater power display Heater Power The temperature controller controls the temperature of the bath by pulsing the heater on and off The total power being applied to the heater is deter mined by the duty cycle or the ratio of heater on time to the pulse cycle time This value may be estimated by watching the red green control indi cator light or read directly from the digital display By knowing the amount of heating the user can tell
39. dershoot of about 0 5 C Refrigeration Bath cooling below 50 C is provided by a compact refrigeration system The system utilizes the ozone safe R 507 refrigerant The refrigerant is metered through an automatic expansion valve to achieve bath temperatures as low as 20 C The evaporator and heater are sandwiched to the sides of the tank This provides the precision control over heat gains and losses required for high stability The refrigeration is not required to maintain the bath above 45 to 50 C Continuous use of the refrigeration above 50 C will dam age the compressor The refrigeration may be used for short periods of time 35 7320 User s Guide for cooling down the bath to a lower temperature Do not exceed 60 min utes cooling above 50 36 9 Controller Operation 9 1 9 2 Controller Operation This chapter discusses in detail how to operate the bath temperature con troller using the front control panel Using the front panel key switches and LED display the user may monitor the bath temperature set the temperature set point in degrees C or F monitor the heater output power adjust the controller proportional band set the cutout set point and program the probe calibration parameters operating parameters serial and IEEE 488 in terface configuration and controller calibration parameters Operation is summarized in Figure 5 Bath Temperature The digital LED display on the front panel allows dir
40. e Press SET to set the BAUD to the new value or EXIT to abort the operation and skip to the next parameter in the menu Sample Period The sample period is the next parameter in the menu and prompted with SAnPLE The sample period is the time period in seconds between tem perature measurements transmitted from the serial interface If the sample rate is set to 5 the bath transmits the current measurement over the serial interface approximately every five seconds The automatic sampling is dis abled with a sample period of 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 Duplex Mode The next parameter is the duplex mode indicated with g UPL The duplex mode be set to half duplex HALF or full duplex FULL With full duplex any commands received by the bath via the serial interface are im mediately echoed or transmitted back to the device of origin With half du plex the commands are executed but not echoed The default setting is full duplex The mode may be changed using UP or DOWN and pressing SET Linefeed The final parameter in the serial interface menu is the linefeed mode This parameter enables dn or disables oF F transmission of a linefeed character LF ASCII 10 after transmission of any carriage return The de fault setting is with linefeed on
41. e Turn off the cooling to reach and control at higher temperatures When setting the set point temperature be careful not to exceed the tem perature limit of the bath fluid The over temperature cutout should be cor rectly set for added safety See Section 9 8 Cutout To obtain optimum control stability adjust the proportional band as dis cussed in Section 9 7 Proportional Band 17 5 Installation 5 1 5 2 5 3 5 3 1 Installation Caution Read Section 6 entitled BATH USE before placing the bath into service Bath Environment The Model 7320 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 Allow plenty of space around the bath for air circulation The top surface of the bath may become hot at high temperatures Beware of the danger of accidental fluid spills A fume hood should be used to remove any vapors given off by hot bath fluid Dry out Period If this equipment is used in a manner not specified by the manufacturer the protection provided by the equipment may be impaired Before initial use or after transport or after storage in humid or semi humid environments or anytime the bath has not been energized for more than 10 days the instrument needs to be energized for a dry out period of 2 hours before i
42. e unit Volume 2 4 gal 9 2 liters Weight 78 Ib 35 4 kg Size 12 x 24 5 x 23 305 mm x 622 mm x 584 mm Safety OVERVOLTAGE Installation CATEGORY II Pollution Degree 2 per IEC 1010 1 Cooling Capacity 600 BTU h Refrigeration R 507 single stage Interface Package RS 232 included IEEE 488 optional tRated at listed 115 V or optional 230 V 11 7320 User s Guide 12 3 2 3 3 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 e temperature range 5 40 C 41 104 F e ambient relative humidity maximum 80 for temperatures 31 C de creasing linearly to 50 at 40 e pressure 75kPa 106kPa e mains voltage within 10 of nominal e vibrations in the calibration environment should be minimized e altitudes less than 2000 meters e indoor use only Warranty Hart Scientific Inc Hart warrants this product to be free from defects in material and workmanship under normal use and service for a period as stated in our current product catalog from the date of shipment This war ranty extends only to the original purchaser and shall not ap
43. ear the boiling point of the fluid the temperature sta bility 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 decomposi tion of the fluid begins Further increasing the temperature may accelerate decomposition to the point of danger or impracticality 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 con troller response The stirrer is precisely adjusted for optimum performance Power Power to the bath is provided by an AC mains supply Refer to Section 3 1 Specifications for power details Refer to and read the CAUTION at the front of the manual concerning brownout and over voltage protection Check the back panel label for the correct voltage and frequency prior to energiz ing the unit Power to the bath passes through a filter to prevent switching Spikes from being transmitted to other equipment To turn on the bath switch the control panel power switch to the ON posi tion The stirring motor will turn on the LED display will begin to show the bath temperature and the heater will turn on or off until the bath tempera ture reaches the programmed set point When powered on the control panel display will briefly show a four digit number This number indicates the number of
44. ect viewing of the ac tual bath 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 e5 00 Bath temperature in degrees Celsius The temperature display function may be accessed from any other function by pressing the EXIT button Reset Cutout If the over temperature cutout has been triggered then the temperature dis play will alternately flash cutout Indicates cutout condition The message will continue to flash until the temperature is reduced and the cutout is reset The cutout has two modes automatic reset and manual reset The mode determines how the cutout is reset which allows the bath to heat up again When in automatic mode the cutout will reset itself as soon as the tempera ture is lowered below the cutout set point With manual reset mode the cut out must be reset by the operator after the temperature falls below the set point When the cutout is active and the cutout mode is set to manual reset then the display will flash cutout until the user resets the cutout To access the reset cutout function press the SET button SET Access cutout reset function The display will indicate the reset function 37 7320 User s Guide
45. ector Connector DB 9 Pin DB 25 Pin INC 2RxD 2TxD 3TxD 3RxD 4NC o 4 RTS 5 GND 5 15 6NC r 6 DSR 7 RIS 7 GND 8 5 lt 800 INC e 20 DIR Figure 7 Serial Communications Cable Wiring Setup Before operation the serial interface of the bath must first be set up by pro gramming the BAUD rate and other configuration parameters These param eters are programmed within the serial interface menu To enter the serial parameter programming mode first press EXIT while pressing SET and release to enter the secondary menu Press SET re peatedly until the display reads P ob E This is the menu selection Press UP repeatedly until the serial inter face menu is indicated with SE c IRL Finally press SET to enter the serial parameter menu In the serial inter face parameters menu are the BAUD rate the sample rate the duplex mode and the linefeed parameter BAUD Rate The BAUD rate is the first parameter in the menu The display will prompt with the BAUD rate parameter by showing B AU g Press SET to choose to set the BAUD rate The current BAUD rate value is displayed The BAUD rate 10 Digital Communication Interface 10 1 2 2 10 1 2 3 10 1 2 4 10 1 3 10 2 of the bath may be programmed to 300 600 1200 or 2400 BAUD The BAUD rate is pre programmed to 2400 BAUD Use UP or DOWN to change the BAUD rate valu
46. er measured 100 1 C giving an error of 0 1 59 7320 User s Guide 60 11 3 11 4 Computing RO and ALPHA Before computing the new values for RO and ALPHA the current values must be known The values may be found by either accessing the probe calibra tion menu from the controller panel or by inquiring through the digital in terface The user should keep a record of these values in case they may need to be restored in the future The new values RO and ALPHA are com puted by entering the old values for RO and ALPHA the calibration tempera ture set points t and ty and the temperature errors err and err into the following equations Ry n ty t 1 ALPHA t Jerr 1 ALPHA t err ty t ALPHA H ALPHA If for example RO and ALPHA were previously set for 100 000 and 0 0038500 respectively and the data for err and err were as given above then the new values RO and ALPHA would be computed as 110 116 and 0 0038302 respectively Program the new values RO and ALPHA into the controller Check the calibration by setting the temperature to t and ty and measuring the errors again If desired the calibration procedure may be repeated again to further improve the accuracy Calibration Example The bath is to be used between 25 and 75 and it is desired to calibrate the bath as accurately as possible for operation within this range The cur rent values f
47. everal fluids are shown in Table 2 Table of Bath Fluids Fluid manufacturers can also provide this information The thermal expansion coefficients are shown in units of cm cm C however the values are the same for any units of length Divide the value by 1 8 for F coefficients The following equation may be used to find the desired depth D D K T Ts 1 Or Dg D K T Ts 1 where lt The Maximum Fill Depth Where K Expansion coefficient T Ending temperature T Starting temperature D Ending depth D Starting depth The maximum fill depth is typically 0 5 to 0 8 inches below the level of the gasket at the top of the bath tank not the top of the bath lid Judgement must be made with different stirring arrangements to prevent splashing on the gasket or lid of the bath Example The final depth of Dow Corning 710 silicone oil in the bath tank is to be 9 2 inches when heated from 25 to 300 C What should the starting depth be Expansion coefficient for 710 oil on Table 2 K 0 00077 inch inch C General Operation 8 1 6 8 1 7 8 1 8 Ending temperature 300 C Starting temperature 25 Ending depth D 9 2 inches D 9 2 0 00077 300 25 1 7 59 inches Electrical Resistivity Electrical resistivity describes how well the fluid insulates against the flow of electric current In some applications such as measuring the resistance of bare temperature sensors it may be i
48. f when the unit is used above 60 C The Factory Reset Sequence should be performed only by authorized personnel if no other action is successful in correcting a malfunction You must have a copy of the most recent Report of Test to restore the test parameters DO NOT operate this instrument in an excessively wet oily dusty or dirty environment The unit is a precision instrument Although it has been designed for optimum durability and trouble free operation it must be handled with care Position the unit before the tank is filled with fluid Use the han dles provided to move the unit Due to the weight of the compressor it may require two people to safely move the bath If two people are used place one person in the front and one person in the back of the unit carefully slide hands under the unit and lift in unison The area containing the compressor is heavier than the rest of the unit Do not move a unit filled with fluid Most probes have handle temperature limits Be sure that the probe handle temperature limit is not exceeded in the air above the instru ment 1 Before You Start 1 3 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 struck stressed or over heated COLD BATHS Refrigerated baths require that the condensing coil be cleaned periodi cally Accumulation of dust and dirt
49. from the bath front panel The width may be set to discrete values in degrees C or F depending on the selected units The optimum proportional band width setting may be deter mined by monitoring the stability with a high resolution thermometer or with the controller percent output power display Narrow the proportional band width to the point at which the bath temperature begins to oscillate and then increase the band width from this point to 3 or 4 times wider Ta ble 3 lists typical proportional band settings for optimum performance with a variety of fluids at selected temperatures 43 7320 User s Guide dd 9 8 The proportional band adjustment may be accessed within the secondary menu Press SET and EXIT to enter the secondary menu and show the heater power Then press SET to access the proportional band Access heater power in secondary menu To change the proportional band press UP or DOWN e Decrement display NESFRERa RRDXEES EA SER SERERSE ERR ERES To accept the new setting and access the cutout set point press SET Pressing EXIT will exit the secondary menu ignoring any changes just made to the proportional band value SET Accept the new proportional band setting Cutout As a protection against software or hardware fault shorted heater triac or user error the bath is equipped with an adjustable heater cutout device that will shut off power to the heater if the bath temperature e
50. ge protection Check the back panel label for the correct voltage and frequency prior to energiz ing the unit 21 6 Bath Use 6 1 6 2 Bath Use A Caution Read this section entitled BATH USE before placing the bath in service The information in this section is for general information only It is not de signed to be the basis for calibration laboratory procedures Each laboratory needs to write their specific procedures General Be sure to select the correct fluid for the temperature range of the calibra tion Bath fluids should be selected to operate safely with adequate thermal properties to meet the application requirements Also be aware that fluids expand when heated and could overflow the bath if not watched Refer to General Operation Section 8 for information specific to fluid selection and to the MSDS sheet specific to the fluid selected Generally baths are set to one temperature and used to calibrate probes only at that single tempera ture This means that the type of bath fluid does not have to change Addi tionally 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 temperatu
51. h may be connected to a computer or other equipment This allows the user to set the bath temperature monitor the temperature and access any of the other controller functions all using re mote communications equipment In addition the cooling may be controlled using the interface To control the cooling with the interface the cooling power switch must be OFF Serial Communications The RS 232 serial interface allows serial digital communications over fairly long distances 15 24 meters With the serial interface the user may access any of the functions parameters and settings discussed in Section 9 Con troller Operation with the exception of the BAUD rate setting The serial in terface operates with eight data bits one stop bit and no parity Wiring The serial communications cable attaches to the bath through the DB 9 connector at the back of the instrument Figure 7 shows the pin out of this connector and suggested cable wiring To eliminate noise the serial cable 51 7320 User s Guide 52 10 1 2 10 1 2 1 should be shielded with low resistance between the connector DB 9 and the shield RS 232 Cable Wiring for IBM PC and Compatibles Instrument Computer DTE Connector Connector DB 9 Pin DB 9 Pin INC 100 2RxD 2RxD 3TxD 3TxD ANC e 4 DTR 5 GND 5 GND 6NC 6 DSR 7RIS EUM 7 RIS 8 5 8 15 9NC 9NC Instrument Computer DTE Conn
52. he previ ous character A terminating CR is implied with all commands Cooling Control To control the refrigeration power with the serial interface the front panel cooling switch must be off The refrigeration power function is controlled with serial F2 command Setting the F2 value to O turns the refrigeration off and setting it to 1 turns it on F2 alone will return O or 1 showing the state of the refrigeration power control 57 11 Calibration Procedure 11 11 1 11 2 Calibration Procedure In some instances the user may want to calibrate the bath to improve the temperature set point accuracy Calibration is done by adjusting the control ler probe calibration constants RO and ALPHA so that the temperature of the bath as measured with a standard thermometer agrees more closely with the bath set point The thermometer used must be able to measure the bath fluid temperature with higher accuracy than the desired accuracy of the bath By using a good thermometer and carefully following procedure the bath can be calibrated to an accuracy of better than 0 02 C over a range of 100 degrees Calibration Points In calibrating the bath RO and ALPHA are adjusted to minimize the set point error at each of two different bath temperatures Any two reasonably sepa rated bath temperatures may be used for the calibration however best re sults will be obtained when using bath temperatures which are just within the most useful operati
53. her sources Depending on the desired tem perature range any of the following fluids as well as others may be used in the bath e Water e Ethylene glycol water e Mineral oil e Silicone oil Fluids are discussed in detail in Section 8 1 Heat Transfer Fluid Remove any access hole cover from the bath and check the tank for foreign matter dirt remnant packing material etc Fill the bath with clean unpolluted fluid Fill the bath carefully through the large rectangular access hole to a level that will allow for stirring and ther mal expansion Section 8 1 5 Thermal Expansion explains fluid expansion 5 Installation 5 4 DO NOT turn on the bath without fluid in the tank Maximum and minimum fill levels are indicated on the slotted baffle inside the tank Carefully moni tor the bath fluid level as the bath temperature rises to prevent overflow or splashing Remove excess hot fluid if necessary with caution MAX FILL MNFILL Figure 2 Tank Baffle Showing Minimum and Maximum Fill Levels 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 Refer to and read the CAUTION at the front of the manual concerning brownout and over volta
54. id for specific information on bath fluids and Section Cutout 15 7320 User s Guide 16 4 3 4 4 Set up of the bath requires careful unpacking and placement of the bath filling the bath with fluid and connecting power Consult Section 5 Instal lation for detailed instructions for proper installation of the bath Be sure to place the bath in a safe clean and level location Fill the bath tank with an appropriate liquid For operation at moderate bath temperatures clean distilled water works well Carefully pour the fluid into the bath tank through the large rectangular access hole above the tank avoiding spilling any fluid The fluid must not exceed a height of 12 7 20 3 mm 0 5 0 8 inches below the bottom of the lid NOT the access cover Power Plug the bath power cord into a mains outlet of the proper voltage fre quency and current capability Refer to Section 3 1 Specifications for power details Refer to and read the CAUTION at the front of the manual concerning brownout and over voltage protection Check the back panel label for the correct voltage and frequency prior to energizing the unit Turn the bath on using the front panel POWER switch The bath will turn on and begin to heat or cool to reach the previously programmed tempera ture set point The front panel LED display will indicate the actual bath temperature Set the cooling switch to OFF for temperatures above approx imately 45 Set the s
55. ion Read Section 6 entitled BATH USE before placing the bath in service This chapter gives a brief summary of the steps required to set up and oper ate the bath This should be used as a general overview and reference and not as a substitute for the remainder of the manual Please read Section 5 Installation through Section 8 General Operation carefully before operating the bath Unpacking Unpack the bath carefully and inspect it for any damage that may have oc curred during shipment If there is shipping damage notify the carrier im mediately Verify that all components are present e 7320 Bath e RS 232 Cable e Access Hole Cover e Drain Valve e Manual e Report of Test If you are missing any item please call a Hart Authorized Service Center see Section 1 3 Set Up A Caution The drain valve must be installed on the back of the bath be fore attempting to fill the tank with fluid See Section 5 3 on page 19 for drain installation instructions A Warning The instrument is equipped with a soft cutout user settable firmware and a hard cutout set at the factory Check the flash point boiling point or other fluid characteristic applicable to the circum stances of the unit operation Ensure that the soft cutout is adjusted to the fluid characteristics of the application As a guideline the soft cut out should be set 10 C to 15 C below the flash point of the bath fluid See Section 8 1 Heat Transfer Flu
56. it is equipped with a soft cutout user settable firmware and a hard cutout set at the factory Check the flash point boiling point or other fluid characteristic applicable to the circumstances of the unit op eration Ensure that the soft cutout is adjusted to the fluid characteris tics of the application 1 2 2 A Cautions To avoid possible damage to the instrument follow these guidelines THE DRAIN VALVE MUST BE INSTALLED ON THE BACK OF THE BATH BEFORE ATTEMPTING FILL THE TANK WITH FLUID See Section 5 3 page 19 for drain installation instructions Always operate this instrument at room temperature between 41 F and 104 F 5 C to 40 C Allow sufficient air circulation by leaving at least 6 inches 15 cm of clearance around the instrument DO NOT overfill the bath Overflowing liquid may damage the electrical system Be sure to allow for thermal expansion of the fluid as the bath temperature increases See Section 5 3 Bath Preparation and Filling for specific instructions Read Section 6 Bath Use before placing the unit into service 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 unit The refrigeration may be damaged or the lifetime shortened if the set point temperature is set above 60 C for more than one hour with the refrigeration manually on Ensure that the refrigeration is of
57. izes as discussed in Sec tion 9 7 Proportional Band 69 7320 User s Guide 70 14 2 14 2 1 Problem Causes and Solutions The controller erratically heats then cools control is unstable If both the bath temperature and output power do not vary periodically but in a very erratic manner the prob lem may be excess noise in the system Noise due to the control sensor should be less than 0 001 C However if the probe has been damaged or has developed an inter mittent short erratic behavior may exist Check for a damaged probe or poor connection between the probe and bath Intermittent shorts in the heater or controller electronic circuitry may also be a possible cause Contact a Hart Au thorized Service Center see Section 1 3 for assistance The bath does not achieve low temperatures Too much heating or not enough cooling can cause this problem Check that the control indicator glows green showing that the controller is attempting to cool The heaters may be disabled as a test by temporarily remov ing the heater fuses Insufficient cooling may be caused by lack of refrigerant because of a leak in the system Refer to the Charging In structions Section 12 Check the sight glass to verify the presence of liquid refrigerant It may be difficult to tell if the glass is completely full or completely empty Verify by watching the glass while the compressor is being turned on The controller does not
58. ld only be used by Trained Personnel e If this equipment is used in a manner not specified by the manufac turer the protection provided by the equipment may be impaired e Before initial use or after transport or after storage in humid or semi humid environments or anytime the instrument has not been en ergized 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 1010 1 If the product is wet or 1 Before You Start 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 degree centigrade for 4 hours or more DO NOT operate high temperature baths 500 C near flammable mate rials Extreme temperatures could ignite the flammable material e Overhead clearance is required Do not place the instrument under a cabinet or other structure Always leave enough clearance to allow for safe and easy insertion and removal of probes e The instrument is intended for indoor use only BURN HAZARD e Extremely cold temperatures may be present in this equipment Freezer burns and frostbite may result if personnel fail to observe safety precautions e High temperatures may be present in this equipment Fires and severe burns may result if personnel fail to observe safety precautions ELECTRICAL HAZARD e The
59. m may be caused by an actual difference in tem perature between the points where the control probe and thermometer probe measure temperature by erroneous bath calibration parameters or by a damaged control probe Check that the bath has an adequate amount of fluid in the tank and that the stirrer is operating properly Check that the thermometer probe and control probe are both fully inserted into the bath to minimize temperature gradient errors Check that the calibration parameters are all correct ac cording to the Report of Test If not re program the con stants The memory backup battery may be weak causing errors in data as described in the problem The display flashes cutout and an incorrect process tem perature Check that the control probe has not been struck bent or damaged If the cause of the problem remains un known contact a Hart Authorized Service Center see Section 1 3 for assistance The controller shows that the output power is steady but the process temperature is unstable If the bath temperature does not achieve the expected de gree of stability when measured using a thermometer try adjusting the proportional band to a narrower width as discussed in Section 9 7 Proportional Band The controller alternately heats for a while then cools The proportional band being too narrow typically causes this oscillation Increase the width of the proportional band until the temperature stabil
60. mage to equipment product or facilities resulting from the use of these fluids The user of the bath is re sponsible 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 About the Graph The fluid graph visually illustrates some of the important qualities of the flu ids shown Temperature Range The temperature scale is shown in degrees Celsius The shaded bands indicate the fluids general range of application Qualities including pour point freeze point important viscosity points flash point boiling point and others may be shown Freezing Point The freezing point of a fluid is an obvious limitation to stir ring As the freezing point is approached high viscosity may also limit performance Pour Point This represents a handling limit for the fluid 31 7320 User s Guide Table 2 Table Of Various Bath Fluids And Their Properties Fluid Lower Upper Thermal Thermal Hart Part Temperature Temperature Flash Viscosity Specific Specific Heat Conductivity Expansion Resistivity No Limit Limit Point centistokes Gravity c
61. maintain controller parame ters or parameters are reset each time the power to the unit is removed Comments Directive Note Before performing the memory check you need to record the controller calibration parameters found in the CAL menu of the instrument and any user adjusted pa rameters that you have changed such as the programma ble set points and proportional band Memory Check Doing a memory check is the easiest way to verify the ability of the battery to maintain controller parameters 1 Power off the instrument 2 Disconnect the instrument from AC power for 10 seconds 3 Reconnect the AC power and power on the instrument 4 If the display shows InIT and or the cycle count shows a low number such as 0002 the battery is spent and Should be replaced Contact a Hart Scientific Authorized Service Center for assistance 5 After replacing the battery you must reprogram the calibration and user adjustable parameters into the controller Hart Scientifics equipment has been tested to meet the European Electro magnetic Compatibility Directive EMC Directive 89 336 EEC The Declara tion of Conformity for your instrument lists the specific standards to which the unit was tested 14 Troubleshooting 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 IEC 1010 1 EN 61010 1 and the
62. mportant that little or no electrical leakage occur through the fluid In such conditions choose a fluid with very high electrical resistivity Fluid Lifetime Many fluids degrade over time because of vaporization water absorption gelling or chemical break down Often the degradation becomes significant near the upper temperature limit of the fluid substantially reducing the fluid s lifetime Safety When choosing a fluid always consider the safety issues associated Obvi ously where there are extreme temperatures there can be danger to person nel and equipment Fluids may also be hazardous for other reasons Some fluids may be considered toxic Contact with eyes skin or inhalation of va pors may cause injury proper fume hood must be used if hazardous or bothersome vapors are produced A Warning Fluids at high temperatures may pose danger from BURNS FIRE and TOXIC FUMES Use appropriate caution and safety equip ment Fluids may be flammable and require special fire safety equipment and pro cedures An important characteristic of the fluid to consider is the flash point The flash point is the temperature at which there is sufficient vapor given off so that when there is adequate oxygen present and an ignition source is applied the 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
63. n secondary menu CO 1102 i Cutout set point To change the cutout set point press UP or DOWN Decrement display COs 151 New cutout set point To accept the new cutout set point press SET SET Accept cutout set point The next function is the configuration menu Press EXIT to resume display ing the bath temperature Controller Configuration The controller has a number of configuration and operating options and cal ibration parameters which are programmable via the front panel These are accessed from the secondary menu after the cutout set point function by pressing SET There are 5 sets of configuration parameters probe param eters operating parameters serial interface parameters IEEE 488 interface parameters and controller calibration parameters The menus are selected using the UP and DOWN keys and then pressing SET Probe Parameters The probe parameter menu is indicated by 45 7320 User s Guide 46 9 10 1 9 10 2 9 11 9 11 1 Pr bE Probe parameters menu Press SET to enter the menu The probe parameters menu contains the parameters RO and ALPHA which characterize the resistance temperature relationship of the platinum control probe These parameters may be ad justed to improve the accuracy of the bath This procedure is explained in detail in Section 11 Calibration Procedure The probe parameters are accessed by pressing SET after the name
64. nd right sides Pull the front panel up and out to remove 65 7320 User s Guide 66 If a hazardous material is spilt on or inside the equipment the user is responsible for taking the appropriate decontamination steps as out lined by the national safety council with respect to the material MSDS sheets applicable to all fluids used in the baths should be kept in close proximity to the instrument If the mains supply cord becomes damaged replace it with a cord with the appropriate gauge wire for the current of the bath If there are any questions call a Hart Authorized Service Center see Section 1 3 for more information Before using any cleaning or decontamination method except those recommended by Hart users should check with a Hart Scientific Au thorized Service Center see Section 1 3 to be sure that the proposed method does not damage the equipment If the instrument is used in a manner not in accordance with the equipment design the operation of the bath may be impaired or safety hazards may arise The over temperature cutout should be checked every 6 months to see that it is working properly In order to check the user selected cutout follow the controller directions Section 9 8 Cutout for setting the cut out Both the manual and the auto reset option of the cutout should be checked Set the bath temperature higher than the cutout Check to see if the display flashes cutout and if the temperature is decreasing
65. ng range of the bath The further apart the calibra tion temperatures the larger will be the calibrated temperature range but the calibration error will also be greater over the range If for instance 0 C and 100 C are chosen as the calibration temperatures then the bath may achieve an accuracy of maybe 0 03 C over the range 10 to 110 C Choos ing 30 and 70 may allow the bath to have a better accuracy of maybe 0 01 over the range 25 to 75 C but outside that range the accuracy may be only 0 05 Measuring the Set point Error The first step in the calibration procedure is to measure the temperature er rors including sign at the two calibration temperatures First set the bath to the lower set point which we will call t Wait for the bath to reach the set point and allow 15 minutes to stabilize at that temperature Check the bath stability with the thermometer When both the bath and the thermom eter have stabilized measure the bath temperature with the thermometer and compute the temperature error err which is the actual bath tempera ture minus the set point temperature If for example the bath is set for a lower set point of tj O C and the bath reaches a measured temperature of 0 3 C then the error is 0 3 C Next set the bath for the upper set point and after stabilizing measure the bath temperature and compute the error erry For this example we will suppose the bath was set for 100 C and the thermomet
66. ntroller will automatically turn off the heater with a second mechani cal relay anytime the bath temperature is more than a certain amount above the set point temperature a second protection device the controller is also equipped with a separate thermocouple temperature monitoring circuit which will shut off the heater if the temperature exceeds the cutout set point The controller allows the operator to set the bath temperature with high resolution set the cutout adjust the proportional band monitor the heater output power and program the controller configuration and calibration pa rameters The controller may be operated in temperature units of degrees Celsius or Fahrenheit The controller is operated and programmed from the front control panel using the four key switches and digital LED display Re mote digital operation with the controller is possible via the standard RS 232 serial port The controller may be optionally equipped with an IEEE 488 GPIB digital interface Operation of the controller using the front control panel is discussed following in Section 9 Controller Operaton Oper ation using the digital interface is discussed in Section 10 Digital Communi cation Interface When the controller is set to a new set point the bath will heat or cool to the new temperature Once the new temperature is reached the bath usu ally takes 10 15 minutes for the temperature to settle and stabilize There may be a small overshoot or un
67. of the parameter is displayed The value of the parameter may be changed using the UP and DOWN buttons After the desired value is reached press SET to set the parameter to the new value Pressing EXIT will cause the parameter to be skipped ignoring any changes that may have been made HO This probe parameter refers to the resistance of the control probe at O C Normally this is set for 100 000 ohms ALPHA This probe parameter refers to the average sensitivity of the probe between and 100 C Normally this is set for 0 00385 Operating Parameters The operating parameters menu is indicated by PAr Operating parameters menu Press UP to enter the menu The operating parameters menu contains the cutout reset mode parameter Cutout Reset Mode The cutout reset mode determines whether the cutout resets automatically when the bath temperature drops to a safe value or must be manually reset by the operator The parameter is indicated by CEorSE Cutout reset mode parameter Press SET to access the parameter setting Normally the cutout is set for manual mode Cko r St j Cutout set for manual reset To change to automatic reset mode press UP and then SET 9 Controller Operation 9 12 9 12 1 9 12 2 CtozRuto Cutout set for automatic reset Serial Interface Parameters The serial RS 232 interface parameters menu is indicated by Serial RS 232 interface parameters men
68. om the set point due to varying external conditions This is because the power output changes very little with temperature and 9 Controller Operation 7320 the controller cannot respond very well to changing conditions or noise in the system If the proportional band is too narrow the bath temperature may swing back and forth because the controller overreacts to temperature vari ations For best control stability the proportional band must be set for the optimum width Proportional Band too Narrow Proportional Band too Wide Optimum Proportional Band a Y Figure 6 Bath Temperature Fluctuation At Various Proportional Band Settings The optimum proportional band width depends on several factors among which are fluid volume fluid characteristics viscosity specific heat thermal conductivity heater power setting operating temperature and stirring Thus the proportional band width may require adjustment for best bath sta bility when any of these conditions change Of these the most significant factors affecting the optimum proportional band width are heater power setting and fluid viscosity The proportional band should be wider when the higher power setting is used so that the change in output power per change in temperature remains the same The proportional band should also be wider when the fluid viscosity is higher because of the increased response time The proportional band width is easily adjusted
69. on the condenser will result in pre mature failure of the compressor This bath has been equipped with a brownout and over voltage pro tection device as a safety feature to protect the system components Mode of Operation This bath needs to be plugged into the line volt age for at least 2 minutes before operation This is only necessary for the first time that the bath is energized or when it is moved from one location to another Turning the bath ON or OFF does not trigger the delay If a High Low voltage condition exists for longer than 5 seconds the bath de energizes An amber indicator on the back panel lights when this condition exists Re energization is automatic upon correction of the fault condition and after a delay cycle of about 2 minutes If a fault condition exists upon application of power the bath will not energize Under and Over Voltage Protection at 115 VAC Voltage Cutout 12 5 101 129 VAC Voltage Cut In 7 5 106 124 VAC Under and Over Voltage Protection at 230 VAC Voltage Cutout 12 5 203 257 VAC Voltage Cut In 7 596 213 247 VAC Hart Scientific Authorized Service Centers Please contact one of the following authorized Service Centers to coordinate service on your Hart product Hart Scientific Inc 799 E Utah Valley Drive American Fork UT 84003 9775 USA Phone 1 801 763 1600 7320 User s Guide Telefax 1 801 763 1010 E mail support hartscientific com
70. or RO and ALPHA are 100 000 and 0 0038500 respectively The calibration points are chosen to be 30 00 and 80 00 C The measured bath temperatures are 29 843 and 79 914 C respectively Refer to Figure 8 for ap plying equations to the example data and computing the new probe constants 11 Calibration Procedure RO 100 000 ALPHA 0 0038500 t 30 00 C measured t 29 843 C ty 80 00 C measured t 79 914 C Compute errors 29 843 30 00 C 0 157 C 79 914 80 00 C 0 086 C Compute RO 0 00385 1 100 000 100 077 p 0 086 x 30 0 0157 x 80 0 80 0 30 0 Compute ALPHA 1 0 00385 x 80 0 0 157 1 0 00385 x 30 0 0 086 800 300 ALPHA Figure 8 Calibration Example 0 00385 0 0038416 61 12 Charging Instructions 12 12 1 12 2 12 3 Charging Instructions The 7320 uses R 507 refrigerant with a polyolester oil Care must be taken to avoid contamination from other types of refrigerants and oils Leak Testing Leak testing should be done with equipment designed for use with R 507 Bubble or ultra sonic leak testing may be viable in some instances Evacuation DO NOT leave the system open for more than 15 minutes Polyolester oils are very hygroscopic Evacuate the system to a minimum of 200 microns Evacuate from both high and low sides of the system Schrader valves pro vide access to the system Charging
71. ply to any product which in Hart s sole opinion has been subject to misuse alter ation abuse or abnormal conditions of operation or handling Software is warranted to operate in accordance with its programmed in structions on appropriate Hart products It is not warranted to be error free Hart s obligation under this warranty is limited to repair or replacement of a product which is returned to Hart within the warranty period and is deter mined upon examination by Hart to be defective If Hart determines that the defect or malfunction has been caused by misuse alteration abuse or abnormal conditions or operation or handling Hart will repair the product and bill the purchaser for the reasonable cost of repair To exercise this warranty the purchaser must forward the product after call ing or writing a Hart Scientific Authorized Service Center see Section 1 3 for authorization The Service Center assumes NO risk for in transit damage THE FOREGOING WARRANTY IS PURCHASER S SOLE AND EXCLUSIVE REM EDY AND IS IN LIEU OF ALL OTHER WARRANTIES EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OR MERCHANT ABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR USE HART SHALL NOT BE LIABLE FOR ANY SPECIAL INDIRECT INCIDENTAL OR CONSE Specifications and Environmental Conditions QUENTIAL DAMAGES OR LOSS WHETHER IN CONTRACT TORT OR OTHERWISE 13 4 Quick Start 4 4 1 4 2 Quick Start A Caut
72. rain Valve Installation Instructions 19 5 3 2 Filing With Fl id 2 llle 20 POWER a morst oS ee E E ey UE eds Rx pa 21 6 4 23 6 1 General cr 4 sn koe om Row Ro Ro ROGER E GOS uox d 23 6 2 Comparison 23 6 3 Calibration of Multiple Probes 24 1 Parts and Controls 25 71 1 25 72 26 7 3 Back Panel acd ha 26 8 1 21 81 HeatTransfer 27 8 1 1 Temperature Range soro s Ro ed dd ok Re 21 8 1 2 VISCOSITY 9 s pho e oom v RR hme DE 21 8 1 8 Specific Heat 2 4455 ok xy EROR RS 21 8 1 4 Thermal Conductivity so sse tore n om o om ooo me 28 8 1 5 Thermal Expansions s s s s aa cay rece Rs bp RR UR COS 28 8 1 6 Electrical Resistivity hae ae ew 29 8 1 7 Fluid 29 8 1 8 Safety oma 9 Gabe te dhe heeded Bee don ders 29 8 1 9 oc DC a Se awe cep ae 30 8 1 10 Commonly Used Fluids 2 2 30 Wael uu das ee ede od ho wm oh A oe a 30 5110 2 Ethylene Glycol js ee eee noo
73. re 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 Some of the high temperature fluids react violently to water or other liquid mediums Be aware that cleaning the probe can be dangerous if the probe has not cooled to room temperature Additionally high temperature fluids may ignite the paper towels if the probe has not been cooled For optimum accuracy and stability allow the bath adequate stabilization time after reaching the set point temperature Comparison Calibration Comparison calibration involves testing a probe unit under test UUT against a reference probe After inserting the probes to be calibrated into the bath allow sufficient time for the probes to settle and the temperature of the bath to stabilize 23 7320 User s Guide 24 6 3 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 cal ibrated at the same time However stem effect from different types of probes is not totally eliminated
74. rement display C 42 50 New set point value When the desired set point value is reached press SET to accept the new value and access the set point vernier If EXIT is pressed instead then any changes made to the set point will be ignored SET Accept new set point value Set point Vernier The set point value can be set with a resolution of 0 01 C The user may want to adjust the set point slightly to achieve a more precise bath temper ature The set point vernier allows one to adjust the temperature below or above the set point by a small amount with very high resolution Each of the 8 stored set points has an associated vernier setting The vernier is ac cessed from the set point by pressing SET The vernier setting is dis played as a 6 digit number with five digits after the decimal point This is a temperature offset in degrees of the selected units C or F 0 000080 Current vernier value To adjust the vernier press UP or DOWN Unlike most functions the ver nier setting has immediate effect as the vernier is adjusted SET need not be pressed This allows one to continually adjust the bath temperature with the vernier as it is displayed Increment display 0 00090 New vernier setting 9 Controller Operation 9 4 Next press EXIT to return to the temperature display or SET to access the temperature scale units selection SET Access scale units Temperature Scale Units The temperature s
75. se guidelines must be followed to ensure that the safety mecha nisms in this instrument will operate properly This instrument must be plugged into a 115 VAC 60Hz 230 VAC 50Hz optional AC only elec tric outlet The power cord of the instrument is equipped with a three pronged grounding plug for your protection against electrical shock hazards It must be plugged directly into a properly grounded three prong receptacle The receptacle must be installed in accordance with local codes and ordinances Consult a qualified electrician DO NOT use an extension cord or adapter plug e DO use a ground fault interrupt device This unit contains a liquid A ground fault device is advised in case liquid is present in the electrical system and could cause an electrical shock e Always replace the power cord with an approved cord of the correct rating and type If you have questions contact a Hart Scientific Autho rized Service Center see Section 1 3 e High voltage is used in the operation of this equipment Severe injury or death may result if personnel fail to observe the safety precautions Before working inside the equipment turn off the power and discon nect the power cord BATH FLUIDS e Fluids used in this unit may produce noxious or toxic fumes under cer tain circumstances Consult the fluid manufacturer s MSDS Material Safety Data Sheet Proper ventilation and safety precautions must be observed 7320 User s Guide The un
76. t can be assumed to meet all of the safety requirements of the IEC 1010 1 If the product is wet or has been in a wet environment take neces sary measures to remove moisture prior to applying power such as storage in a low humidity temperature chamber operating at 50 degree centigrade for 4 hour or more Bath Preparation and Filling A Caution Before filling the tank with fluid the drain valve must be in stalled onto the pipe fitting at the back of the bath Drain Valve Installation Instructions The drain valve attaches to the swage fitting located on the lower backside of the bath See Figure 1 l Place the valve onto the drain fitting and hand tighten in place by turning the hex nut attached to the bath counter clockwise while holding the valve stationary 19 7320 User s Guide 20 5 3 2 2 Using open end wrenches hold the valve in place and tighten the hex nub one quarter turn from the hand tightened position above The valve should be secured in place at this point If not repeat step num ber 2 being careful not to over tighten the assembly Ensure the valve handle is in the closed position before attempting to add fluid to the tank Je of bath Figure 1 Drain Valve Installation IMPORTANT Do Not Over Tighten Follow the installation instructions above Filling With Fluid The Model 7320 Bath is not provided with a fluid Various fluids are avail able from Hart Scientific and ot
77. temperatures may cause insufficient heating Switching to the higher heater power switch setting if available may solve the problem Try reducing cooling capacity by increasing the cooling temperature switching the cooling power switch to LOW or switching off the cooling altogether One or more burned out heaters or blown heater fuses may also cause this problem If the heaters seem to be burned out contact a Hart Authorized Service Center see Section 1 3 for assistance 67 7320 User s Guide 68 Problem Causes and Solutions The controller display flashes cutout and the heater does not operate The display will flash CUToUT alternately with the pro cess temperature If the process temperature displayed seems grossly in error consult the following problem The display flashes cutout and an incorrect process temperature Normally the cutout disconnects power to the heater when the bath temperature exceeds the cutout set point causing the temperature to drop back down to a safe value If the cutout mode is set to AUTO the heater switches back on when the temperature drops If the mode is set to RESET the heater only comes on again when the temperature is reduced and the cutout is manu ally reset by the operator see Section 9 8 Cutout Check that the cutout set point is adjusted to 10 or 20 C above the maximum bath operating temperature and that the cutout mode is set as desired
78. ter power po wer po po 9999 po 1 duty cycle Configuration Menu Probe Menu Read RO calibration r 0 r 10 999 999 10 100 578 parameter Set RO calibration parame r O n 1 100 324 98 0 to terto n 104 9 Read ALPHA calibration al pha al al 9 9999999 al parameter 0 0038573 Set ALPHA calibration pa al pha n al 0 003843 00370 to rameter to n 3 00399 Operating Parameters Menu Read cutout mode cm ode cm cm xxxx cm AUTO 55 7320 User s Guide Interface Command Summary Continued Command Command Returned Acceptable Command Description Format Example Returned Example Values Set cutout mode cm ode r eset a RESET or uto AUTO Set cutout to be reset cm ode r eset cm r manually Set cutout to be reset cm ode a uto cm a automatically Serial Interface Menu Read serial sample setting sa mple sa sa 9 sa 1 Set serial sampling setting sa mple n sa 0 O to 4000 to n seconds Set serial duplex mode du plex f ull h al FULL or HALF f Set serial duplex mode to du plex f ull du f full Set serial duplex mode to du plex h alf du h half Set serial linefeed mode 1f eed on of f ON or OFF Set serial mode to lf eed on lf on on Set serial linefeed mode to If eed of t off Calibration Menu Read BO calibration bO pO b0 9 O parameter Set BO calibration parame bO n 0 0 999
79. to use the same address as the external communicating device The address is indicated by RddrESS IEEE 488 interface address Adjust the value with UP or DOWN and then use SET to set the address to the displayed value Hddz 15 New IEEE 488 interface address Transmission Termination The transmission termination character can be set to carriage return only linefeed only or carriage return and linefeed Regardless of the option se lected the instrument will interpret either a carriage return or a linefeed as a command termination during reception The termination parameter is indicated with EGS IEEE 488 termination pP pl D A AAA B AA Use SET to save the new selection 49 7320 User s Guide 50 9 14 Calibration Parameters The operator of the bath controller has access to a number of the bath cali bration constants namely CTO BO BG H and L These values are set at the factory and must not be altered The correct values are important to the ac curacy and proper and safe operation of the bath These parameters should not be adjusted except in the event the controller s memory fails The user may then restore these values to the factory settings A list of these con stants and their settings are supplied to the user on the Report of Test with the manual A Caution DO NOT change the values of the bath calibration constants 9 14 1 9 14 2 9 14 3
80. u The serial interface parameters menu contains parameters which determine the operation of the serial interface The parameters the menu are BAUD rate sample period duplex mode and linefeed BAUD Rate The BAUD rate is the first parameter in the menu The BAUD rate setting de termines the serial communications transmission rate The BAUD rate parameter is indicated by BRUd Serial BAUD rate parameter Press SET to choose to set the BAUD rate The current BAUD rate value will then be displayed 1200 b Current BAUD rate The BAUD rate of the bath serial communications may be programmed to 300 600 1200 or 2400 BAUD Use UP or DOWN to change the BAUD rate value 2400 b i NewBAUD rate Press SET to set the BAUD rate to the new value or EXIT to abort the op eration and skip to the next parameter in the menu Sample Period The sample period is the next parameter in the serial interface parameter menu The sample period is the time period in seconds between tempera ture measurements transmitted from the serial interface If the sample rate is set to 5 then the bath transmits the current measurement over the serial interface approximately every five seconds The automatic sampling is dis abled with a sample period of O The sample period is indicated by SAPALE Serial sample period parameter rend 47 7320 User s Guide 48 9 12 3 9 12 4 Press SET to choose to set the sample period
81. witch to ON for lower temperatures Setting the Temperature In the following discussion and throughout this manual a solid box around the word SET UP DOWN or EXIT indicates the panel button to press while the dotted box indicates the display reading on the front panel Explanation of the button function or display reading is written at the right To view or set the bath temperature set point proceed as follows The front panel LED display normally shows the actual bath temperature eu 58 Bath temperature display CX When SET is pressed the display shows the set point memory that is cur rently being used and its value Eight set point memories are available Access set point selection 1 25 0 Set point 1 25 0 currently used Press SET to select this memory and access the set point value SET Access set point value 4 Quick Start 205 00 Current value of set point 1 25 00 Press UP or DOWN to change the set point value Increment display 36 80 New set point value Press SET to accept the new value and display the vernier value The bath begins heating or cooling to the new set point SET Store new set point access vernier 0 00000 Current vernier value Press EXIT and the bath temperature will be displayed again Return to the temperature display eu 13 Bath temperature display The bath heats or cools until it reaches the new set point temperatur
82. xceeds a set value This protects the heater and bath materials from excessive tempera tures and most importantly protects the bath fluids from being heated be yond the safe operating temperature preventing hazardous vaporization breakdown or ignition of the liquid The cutout temperature is programma ble by the operator from the front panel of the controller It must always be set below the upper temperature limit of the fluid and no more than 10 de grees above the upper temperature limit of the bath If the cutout is activated because of excessive bath temperature then power to the heater will be shut off and the bath will cool The bath will cool until it reaches a few degrees below the cutout set point temperature At this point the action of the cutout is determined by the setting of the cutout mode parameter The cutout has two selectable modes automatic reset or manual reset If the mode is set to automatic then the cutout will automatically reset itself when the bath temperature falls below the reset temperature allowing the 9 Controller Operation 9 9 9 10 bath to heat up again If the mode is set to manual then the heater will re main disabled until the user manually resets the cutout The cutout set point may be accessed within the secondary menu Press SET and EXIT to enter the secondary menu and show the heater power Then press SET twice to access the cutout set point C Access heater power i

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