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Cryo-con Model 24C - Cryogenic Control Systems, Inc.

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1. Disengage all control loops stop Both control loops are stopped Engage all control Loops control Starts both control loops Ask if control loops are on Return is ON or OFF control 109 Cryo con Model 24C Remote Programming Guide Function Command Comment LOOP Commands Configure control loop outputs Parameter is 1 or 2 corresponding to Loop 1 or Loop 2 Set the setpoint for control loop 1 loop 1 setpt 1234 5 Sets the loop 1 setpoint to 1234 5 Units are taken from the controlling input channel Read the setpoint for control loop 1 loop 1 setpt Reads the loop 1 setpoint as a numeric string Set the controlling source i nput for loop 1 loop 1 source a Sets the Loop 1 controlling source to input channel A Choices are any input channel Set the loop 2 P gain term for PID control loop 2 pgain 123 5 P gain is unit less Set the loop 1 gain term loop 1 igain 66 1 gain has units of seconds Set the loop 2 D gain term loop 2 dgain 10 22 D gain has units of inverse seconds Set the heater range for loop 1 loop 1 range hi Choices are hi high mid medium and low low Read the loop 1 heater range loop 1 range Reports HI MID LOW Read the control mode for loop 1 loop 1 type Returns the control loop type Choices are OFF MAN PID TABLE RAMPT or RAMPP Set the control mode for loop 2 loop 2 ty
2. Control Loop 2 Secondary Heater Output Control loop 2 is a constant current source similar to Loop 1 Full Scale Current Max Output Power Table 13 Loop 2 Heater output ranges Control Types There are four control types available in the Model 24C They are Manual PID PID Table Ramp and Ramp Table All modes are available on all control loops Manual mode operation allows setting the output power manually as a percentage of full scale power PID control allows feedback control using an enhanced PID algorithm that is implemented using 32 bit floating point Digital Signal Processing techniques Enhancements include 1 Noise filtering on the derivative term The D term will provide better control stability but is often not used because without filtering it makes the control loop too sensitive to noise 2 Integrator wind up compensation While slewing to a new setpoint the integrator in the PID loop can build up to a very large value If no compensation is applied overshoot and time to stability at the new setpoint can be delayed for an extremely long time This is especially true in cryogenic environments where process time constants can be very long 3 Dithering and filtering the outputs in order to increase output resolution and improve control stability The PID Table control mode is a PID control loop just as described above However it is used to look up PID and heater range values based on the specified se
3. Query lt Query gt lt Query gt Query data from the instrument Queries can be any of the instrument s commands as described in the Remote Programming Guide Query is generally used with a Response tag to compare the instrument s response to an expected value If there is no Response tag the result of the query is printed but not tested for errors lt Query gt input c sensor lt Query gt lt Query gt input b units K units lt Query gt Response lt Response gt lt Response gt Identifies the expected response to a query This tag must always follow a Query tag otherwise it is ignored When the comparison fails an error text message will be displayed and recorded to a file lt Query gt Relays 1 lt Query gt lt Response gt Lo lt Response gt lt Query gt input c units lt Query gt lt Response gt K lt Response gt lt Should be Kelvin Error if not gt 168 Cryo con Model 24C Appendix F Configuration Scripts Floating Point Response lt Floatresponse gt lt Floatresponse gt Compare the response returned from the instrument against an expected floating point number This tag must always follow a Query tag otherwise it is ignored When the comparison fails an error text message will display The returned value passes the test if within 2 5 of the expected value lt Query gt input a ALAR High lt Query gt lt FloatResponse gt 200 000000 lt FloatResponse gt Pause lt Pause gt lt Pause gt Pro
4. and the key When the cursor is positioned to a field that requires numeric data the keypad keys become hot and pressing one of them will result in the field being selected and numeric entry initiated This is indicated by a flashing cursor When the Enter key is pressed numeric data in the selected field will be checked for range and the instrument s configuration is correspondingly updated Note If the numeric entry is outside of the required range an error is indicated by the display of the previous value of the field 43 Cryo con Model 24C Front Panel Operation Once the entry of numeric data has started it can be aborted by pressing the Home key This will cause the field to be de selected and its value will be unchanged Pressing the ESC key will exit data entry and restore the field to its previous value The 4 key can be used as a backspace Note Up to 20 digits may be entered in a numeric field When digit entry has exceeded the display field width additional characters will cause the display to scroll from right to left When entry is complete the updated display field may not show all of the digits entered because of limited field width however the digits are retained to the full precision of the controller s internal 32 bit floating point format 44 Cryo con Model 24C Front Panel Operation Summary of keypad functions Key Function Description Pow
5. lt Command gt 80 00 lt Command gt 60 00 lt Command gt 40 00 lt Command gt 20 00 0 50 50 00 10 00 ChB MID lt Command gt 0 40 40 00 10 00 ChB Low lt Command gt 0 30 30 00 0 00 ChB Low lt Command gt 0 20 20 00 0 00 ChB Low lt Command gt lt Command gt lt Command gt lt PIDTable gt 171 Cryo con Model 24C Appendix F Configuration Scripts lt SensorCurve gt lt User curve 4 gt lt CalCur gt CALCUR 4 lt CalCur gt lt Curve Name gt lt CalCur gt Test S700 lt CalCur gt lt Curve Type gt lt CalCur gt Diode lt CalCur gt lt Multiplier gt lt CalCur gt 1 000000 lt CalCur gt lt Unit gt lt CalCur gt Volts lt CalCur gt lt Curve Entries gt lt CalCur gt 0 163300 lt CalCur gt 0 173300 lt CalCur gt 0 183400 lt CalCur gt 0 193500 lt CalCur gt 0 203800 lt CalCur gt 0 214100 lt CalCur gt 0 224600 lt CalCur gt 0 235100 lt CalCur gt 0 245800 lt CalCur gt 0 256500 lt CalCur gt 0 267300 lt CalCur gt 0 278100 lt CalCur gt 0 289100 lt CalCur gt 0 300100 lt CalCur gt 0 311100 lt CalCur gt 0 322200 lt CalCur gt 0 333400 lt CalCur gt 0 344600 lt CalCur gt 0 355800 lt CalCur gt 0 367100 lt CalCur gt 0 378400 lt CalCur gt 0 389700 lt CalCur gt 0 401100 lt CalCur gt 0 412500 lt CalCur gt 0 423900 lt CalCur gt 0 435300 lt CalCur gt lt CalCur gt lt SensorCurve gt lt Transactions gt 475 000000 lt CalCur gt 470 000000 lt CalCu
6. 0 095in 2 41mm 4 x AWG 36 Connection All connections should be 4 wire in order to eliminate errors due to lead resistance Leads are coated with Butyl and may be separated by dipping them in Isopropyl Alcohol Lead insulation is heavy Formvar which is difficult to strip Techniques include use of a mechanical stripper or scrapping with a razor blade 165 Cryo con Model 24C Appendix F Configuration Scripts Appendix F Configuration Scripts The Cryo con Utility software package can be used to send configuration scripts to any Cryo con instrument These scripts consist mostly of standard remote commands and queries Scripts can be used to completely configure an instrument including setting custom sensor calibration curves and PID tables They are commonly used in a manufacturing environment to set a baseline state for a target product In the laboratory scripts can be used to save and restore configurations for various experiments XML or Extensible Markup Language is used for the structure and format of script files XML can be generated and edited with a standard text editor but advanced users may want to use one of the commonly available XML editors Since it provides a structure and allows user documentation it is easy to read and understand Configuration scripts have a file extension of xml These files are sent to an instrument by using the Operations gt Send Command File function of th
7. 100 000K Htr Off Channel D 100 000K Htr Off Relay 1 Source ChA Status Auto Off Relay 2 Source ChB Status Auto Off Instrument Status Date 08 01 2009 Time 12 00 11 NewCryocon Cryocon Model 24C 209999 1 10xA Technical Support Contact Cryo con Support Cryo con Model 24C Introduction In order to eliminate ground loop and noise pickup problems commonly associated with IEEE 488 systems the Model 24C moves the internal IEEE 488 circuitry to an optional external module that interfaces directly to the electrically isolated and low noise Ethernet interface This compact module is completely transparent to the IEEE 488 system and does not require changes to customer software or LabView drivers Remote Command Language The Model 24C s remote command language is SCPI compliant according to the IEEE 488 2 specification SCPI establishes a common language and syntax across various types of instruments It is easy to learn and easy to read The SCPI command language is identical across all Cryo con products so that the user s investment in system software is always protected Command Scripts can be used to completely configure an instrument including setting custom sensor calibration curves and PID tables Further scripts can query and test data They are commonly used in a manufacturing environment to set a baseline state and test a target product In the laboratory scripts can be used to save and re
8. Choices are Volts Ohms and LogOhm LogOhm selects the base ten logarithm of ohms and is useful with sensors whose resistance vs temperature curve is logarithmic The Calibration Curve Edit menu From this screen the user can input individual entries into a sensor calibration curve Note that these curves can have up to 200 points requiring the entry of 400 floating point numeric values For lengthy curves you may want to consider using one of the remote interfaces Cryocon provides a free PC utility that uploads or downloads curves which can be created by a text editor 67 Cryo con Model 24C Front Panel Menu Operation The Calibration Curve Edit menu is accessed by pressing the Sensor key scrolling to the desired curve and then scrolling to the Edit field of that curve The procedure for entering or editing a calibration curve is summarized as follows 1 First set the index IX field to the curve entry that you want to enter This will cause the display of data at that index 2 Enter data points values by entering numeric data and pressing Enter 3 Go to the next index by changing the IX field 4 When all data points have been entered the SaveCurve amp Exit field is selected to save the curve Once complete the controller will condition the curve by rejecting invalid entries then sorting the curve in order of ascending sensor unit values Therefore an entry may be deleted by placing a zero or negative number in the
9. LOOP 1 2 3 4 TYPe OFF PID MAN TABLE RAMPP Sets and queries the selected control loop s control type Allowed values are Off loop disabled PID loop control type is PID Man loop is manually controlled Table loop is controlled by PID Table lookup RampP loop is controlled by PID but is in ramp mode RampT loop is controlled by PID Table lookup but is in ramp mode LOOP 1 2 3 4 TABLeix lt ix gt Sets and queries the number of the PID table used when controlling in Table mode Six PID tables are available to store PID parameters vs setpoint and heater range lt ix gt is the loop s control PID table index Table index is in the range of 1 through 6 126 Cryo con Model 24C Remote Programming Guide LOOP 1 RANGe HI MID LOW Sets or queries the control loop s output range Range determines the maximum output power available and is different for a 500 load resistance than for a 250 load Values of heater range for Loop 1 are Hi 500 Load 250 Load Mid Low and Min These correspond to the 50W 25W output power levels shown here The values for loop 2 is 10W corresponding to 10W into a 500 load LOOP 1 2 3 4 RAMP Queries the unit to determine if a temperature ramp is in progress on the specified control loop Note that temperature ramps on the Loop 1 and Loop 2 channels are independent of each other Query response is ON or OFF LOOP 1 2 3 4 RATe lt rate gt Sets and queries the ramp rat
10. Options Go to the Options Setup Menu System Display Alarm Set Pt OOO 42 Cryo con Model 24C Front Panel Operation Keypad Data Entry The keypad is used to enter data and make selections in the various configuration menus Fields require the entry of numeric or enumeration data Enumeration fields are display fields where the value is one of several specific choices For instance the Heater Range field in the Loop 1 setup menu may contain one of only three possible values HIGH MID and LOW There are many enumeration fields that contain only the values ON and OFF Enumeration Fields An enumeration is always indicated by the character in the first column of the field To edit an enumeration field place the cursor at the desired field by using the Navigation keys Then use the or 0 keys to scroll through all of the possible choices in sequence When a field has been changed the cursor will flash over the symbol To select the displayed value press the Enter key To cancel selection without updating the field press the Esc key To select the displayed value press the Enter key To cancel selection without updating the field press the Esc key The cursor will then return to the symbol Numeric Data Fields Numeric data is indicated by a pound sign in the first column of the field The Keypad Keys are used to enter data into numeric fields These keys are the numerals 0 through 9 the period key
11. STB The STB query returns the contents of the Status Byte Register 119 Cryo con Model 24C Remote Programming Guide Control Loop Start Stop Commands STOP Disengage both control loops CONTro1 The control command will cause the instrument to enter the control mode by activating enabled control loops To disable an individual loop set its control type to OFF Note To disengage temperature control use the STOP command System Commands System commands are a group of commands associated with the overall status and configuration of the instrument rather than a specific internal subsystem SYSTem LOCKout ON OFF Sets or queries the remote lockout status indicator Used to enable or lock out the front panel keypad of the instrument thereby allowing or preventing keypad entry during remote operation When the keypad is locked the Remote LED illuminates and most of the keys on the keypad will not function However the Stop key still functions To exit the keypad lock out from the front panel push the Esc button This will clear the Remote LED to indicate that the keypad is now unlocked SYSTem NVSave Save NV RAM to Flash This saves the entire instrument configuration to flash memory so that it will be restored on the next power up Generally only used in environments where AC power is not toggled from the front panel This includes remote and rack mount applications SYSTem REMLed ON OFF Sets
12. The green Remote LED can be turned on or off under program control by the remote interface Use of this LED by a computer connected to the instrument is optional This LED may also indicate that the keypad is locked out To clear the LED and the keypad lockout press the Esc key 45 Cryo con Model 24C Front Panel Operation The Front Panel Display Home Status Displays At the top of the instrument s menu tree are the home status displays They can be selected from anywhere in by pressing the Home 251 445k 296 845k key 300 000K 1 Off Low 100 000K 2 Off Low C Second Stage D Rad Shield The Home display is easily 251 445K 296 845k configured to show only desired data There are four zones each of which may be independently configured RO 600 RuOx 10uV R500 RuOx 1 0mV Pressing the Display key will list the configuration of each zone To change the contents of Home Zone Configuration Menu a zone scroll to the B Zone Loop 1 Status desired zone and press Zone Loop 2 Status the Enter key This will Zone ChC Temperature y Zone ChD Temperature result in a display of all possible selections for the selected zone A summary of the important selections is given below Temperature Displays an input channel temperature in 2x font Above the temperature is the input channel indicator name string and alarm status Below is the sensor type and excitation level Loop Status Displays These displays show t
13. lt Response gt K lt Response gt lt Command gt input b sensor 21 lt Command gt lt Query gt input b temp lt Query gt lt Input gt 170 Cryo con Model 24C Appendix F Configuration Scripts lt Loop gt Loop 1 lt Command gt Loop 1 SetPt 250 lt Command gt lt Command gt Loop 1 Type MAN lt Command gt lt Query gt Loop 1 Type lt Query gt lt Command gt Loop 1 Pman 20 lt Command gt lt Query gt Loop 1 Pman lt Query gt lt Command gt control lt Command gt lt Query gt Loop 1 Outp lt Query gt lt Command gt Stop lt Command gt lt Loop gt lt PIDTable gt lt Download to table 6 gt lt Command gt PIDTABLE 5 table lt Command gt lt Table Name gt lt Command gt LOOP1 Htr lt Command gt lt Table Entries gt lt Command gt 310 00 lt Command gt 280 00 lt Command gt 260 00 lt Command gt 240 00 lt Command gt 220 00 lt Command gt 200 00 lt Command gt 180 00 lt Command gt 160 00 lt Command gt 140 00 lt Command gt 120 00 lt Command gt 100 00 40 00 Default HI lt Command gt gt 30 00 Default HI lt Command gt 30 00 Default HI lt Command gt 30 00 Default HI lt Command gt 30 00 Default HI lt Command gt 20 00 Default HI lt Command gt 20 00 ChA MID lt Command gt 20 00 ChA MID lt Command gt 20 00 ChA MID lt Command gt 70 00 10 00 ChA MID lt Command gt 0 60 60 00 10 00 ChA MID lt Command gt 160 00 150 00 140 00 30 130 00 20 120 00 110 00 100 00 90 00 80 00
14. to the field AC Line field Then AC Line 60Hz select 60 or 50 Hz as required 88 Cryo con Model 24C Basic Setup and Operation To set the Synchronous Filter Taps parameter enter a number between 1 and 25 into the Sync Filt Taps field A setting of 1 turns the filter off Most cryocoolers use a setting of 7 since this is the most common sub multiple of the AC line frequency applied Note If you are not using a cryocooler please leave the Sync Filt Taps field set at the default of 7 Note If you change the setting the Sync Filt Taps setting you will need to re tune the PID control loop 89 Cryo con Model 24C Basic Setup and Operation Viewing a Cryocooler Thermal Signature In order to view a cryocooler s thermal signature and experiment with the synchronous filter the Cryo con Utility Software may be used In the Data Logging menu set the interval field to the minimum allowed value of 0 1 Seconds and then open a strip chart Use the manual settings on the strip chart to zoom in on the temperature The signature with the chart set to the base temperature plus or minus about 0 5K should be observable In order to see the cooler signature set the Sync Filt Taps field to one This disables the removal of the signature From here you can enter various values in order to see the affect of the synchronous filter Shown here is an example of a Cryomech PT403 pulse tube refrigerator wit
15. 0 and for a Positive Temperature Coefficient PTC sensor the value is 1 0 As an advanced function the multiplier field can be used as a multiplier for the entire calibration curve For example a 10KQ Platinum RTD can use a calibration curve for a 1000 Platinum RTD by using a multiplier of 100 0 The fourth line of the header is the sensor units field This may be Volts Ohms or Logohm Generally diode type sensor curves will be in units of Volts and most resistance sensors will be in units of Ohms However many resistance sensors used at low temperature have highly nonlinear curves In this case the use of Logohm units give a more linear curve and provide better interpolation accuracy Logohm is the base 10 logarithm of Ohms Examples of sensor calibration curves that are in units of Ohms include Platinum RTDs and Rhodium lron RTDs Examples of sensors that best use Logohm include Cernox Ruthenium Oxide and Carbon Ceramic After the header block there are two to 200 lines of sensor calibration data points Each point of a curve contains a sensor reading and the corresponding temperature Sensor readings are in units specified by the units line in the curve header Temperature is always in Kelvin The format of an entry is lt sensor reading gt lt Temperature gt Where lt sensor reading gt is a floating point sensor reading and lt Temperature gt is a floating point temperature in Kelvin Numbers are separated by one or more whi
16. 1 0mA 1 40 0 020 0 05 Rdg 40 1 0mA 4 400 0 020 0 05 Rdg 400 1004A 40 4000 0 20 0 05 Rdg 4000 10yA 400 4KQ 2 00 0 05 Rdg AKO 10yA 4K 40KQ 200 0 05 Rdg 100KQ 10uA 40K 100KQ 500 0 1 Rdg Table 9 10mV Constant Voltage Accuracy Specifications While it is possible to measure resistance above100KQ accuracy is not guaranteed The 1 0mV and lower bias settings are provided for use in very low temperature applications lt 1K where errors are often dominated by sensor self heating rather than the accuracy of resistance measurement In the 1 0mV range the Model 24C will have an accuracy of 0 5 over the resistance range of 40 to 10 0KQ 24 Cryo con Model 24C Specifications Features and Functions Control Outputs Number of Loops Four Control Input Either sensor input Loop Update Rate 15Hz per loop Control Type PID table PID Ramp or Manual Autotune Minimum bandwidth PID loop design PID Tables Six user PID tables available for storage of Setpoint vs PID and heater range Up to 16 entries table Setpoint Accuracy Six significant digits Fault Monitors Control loops are disconnected upon detection of a control sensor fault or excessive internal temperature Over Temperature Disconnect Heater may be relay disconnected from user equipment when a specified temperature is exceeded on any selected input Loop 1 Primary Heater Output Type Short circuit protected linear c
17. 1 5 and Subnet Mask of 255 255 255 0 Using these settings the instrument communicates with any computer or device that has an IP addresses in the range of 192 168 1 0 through 192 168 1 255 The user can configure the Model 24C to use any other IP address by going to the Network Configuration Menu TCP IP Data Socket Configuration TCP IP is a connection orientated protocol that is more complex and has higher overhead than UDP The user must bind a TCP IP socket and negotiate a connection before communicating with an instrument The default TCP IP port address is 5000 This can be changed from the front panel by going to the Network Configuration Menu UDP Configuration UDP is a simple connection less protocol that can be used to communicate with Cryo con instruments The user binds a UDP socket and communicates with the instrument in a fashion similar to the older RS 232 style communications UDP uses a port that is the TCP port address plus one Therefore the factory default is 5001 102 Cryo con Model 24C Remote Operation IEEE 488 GPIB Option Configuration The only configuration parameter for the optional GPIB interface is to set the address This is done by using the System Functions Menu described above Once the external GPIB interface is connected to the controller s LAN port configuration is performed by the instrument Note that each device on the GPIB interface must have a unique address Set the instrument s addr
18. 141 PM cs 141 A EE 15 141 RhodiUM ON 21 31 141 ROO cito nidad 141 RID adas 141 Ruthenium Oxide 15 21 30 31 78 79 141 144 161 162 165 178 SO nia di 15 27 78 173 EE ue ME 32 SAM rn 141 Silicon diode inia id 30 173 Silicon Thermisior eener 21 Supported Gensors errereen 21 Thermocouple 12 21 23 30 95 97 98 125 141 143 179 Unt El EEN 121 USB OPM EE Configuratii m iiare aeiia 104 User Calibration Cumves 3 User Configurations 42 59 Utility SoftWare sasina sanirana acasa ieia 13 187
19. 1608 61 1 400 5200 40 8 350 4777 7 65 6 500 9215 6 40 3 400 8159 8 69 6 600 13325 41 7 500 15426 75 3 670 16264 42 2 600 23138 78 6 700 17533 42 4 670 28694 80 800 21789 42 6 700 31100 80 4 900 26045 42 4 800 39179 81 1000 30251 41 7 900 47256 80 4 1100 34373 40 7 1000 55247 79 3 1200 38396 39 7 1100 63119 78 1 1270 41153 39 1200 70842 76 3 1300 42318 38 7 1270 76136 75 2 1400 46131 37 5 1500 49813 36 1 1600 53343 34 5 1640 54712 34 179 Cryo con Model 24C Appendix G Sensor Data Tables 3 2 6257 5 1 03 1 2 5299 6 8 98 4 2 6256 2 1 4 2 5292 10 1 10 6242 9 3 12 3 2 5278 9 11 6 20 6199 2 5 58 4 2 5266 8 12 6 30 6131 3 7 99 10 5181 8 16 40 6040 10 2 20 5014 17 50 5927 7 12 2 30 4846 4 16 6 75 5573 6 16 40 4681 5 16 5 100 5131 2 19 4 50 4515 8 16 7 150 4004 3 25 6 75 4084 6 17 8 200 2575 3 31 4 100 3627 18 8 250 872 57 38 150 2645 2 20 4 273 15 0 39 4 200 1600 1 21 4 300 1067 4 40 8 250 512 81 22 350 3215 5 45 300 597 44 22 4 400 5560 2 48 7 350 1696 3 21 8 500 10735 54 6 400 2805 7 22 7 600 16437 59 2 500 5135 3 23 4 670 20677 61 7 600 7470 7 23 4 180 Cryo con Model 24C Appendix H Rear Panel Connections Appendix H Rear Panel Connections Sensor Connections All sensor connections are made at the rear panel of the Model 24C using
20. 3 4 TYPe OFF PID MAN TABLE RAMPP RAMPT LOOP 1 2 3 4 TABelix lt ix gt LOOP 1 2 3 4 RANGEe HI MID LOW LOOP 1 2 3 4 RAMP LOOP 1 2 3 4 RATe lt rate gt LOOP 1 2 3 4 PGAin lt gain gt LOOP 1 2 3 4 IGAin lt gain gt LOOP 1 2 3 4 DGAin lt gain gt LOOP 1 2 3 4 PMAnual lt pman gt LOOP 1 2 3 4 OUTPwr LOOP 1 2 3 4 HTRRead LOOP 1 2 3 4 HTRHst LOOP 1 LOAD 50 25 LOOP 1 2 3 4 MAXPwr lt maxpwr gt LOOP 1 2 3 4 MAXSet lt maxset gt 116 Remote Programming Guide Cryo con Model 24C Remote Programming Guide LOOP 1 2 3 4 AUTotune STARt LOOP 1 2 3 4 AUTotune EXIT LOOP 1 2 3 4 AUTotune SAVE LOOP 1 2 3 4 AUTotune MODe P PI PID LOOP 1 2 3 4 AUTotune DELTap lt num gt LOOP 1 2 3 4 AUTotune TIMeout lt num gt LOOP 1 2 3 4 AUTotune PGAin LOOP 1 2 3 4 AUTotune PGAin LOOP 1 2 3 4 AUTotune DGAin LOOP 1 2 3 4 AUTotune STATus OVERtemp ENABle ON OFF OVERtemp SOURce A B C D OVERtemp TEMPerature lt temp gt CALcur SENSor lt index gt NAMe name string SENSor lt index gt NENTry SENSor lt index gt UNITs VOLTS OHMS LOGOHM SENSor lt index gt TYPe DIODE ACR PTC100 PTC1K NTC10UA ACR TC70 NONE SENSor lt index gt MULTiply lt multiplier gt RELays 1 2 RELay
21. 4 Model 24C Front Panel Layout 41 Figure 5 Thermocouple Module 95 Figure 6 Thermocouple Gwitches AA 95 Figure 7 Proper Assembly of the Input Connector eee 181 Figure 8 Diode and Resistor Sensor Connechons eee 182 Figure 9 RS 232 Null Modem Cable 184 Cryo con Model 24C Index of Tables Table 1 Model 24C Instrument Accessories enen 14 Table 2 Cryogenic ACcessories 15 Table 3 Loop 1 Output Gummanm 18 Table 4 Control Type Gummanm conc nana n cnn ncnnnnnncn 19 Table 5 Supported Sensor Tvpes 21 Table 6 Accuracy and Resolution for PTC hResisiors 22 Table 7 Minimum and Maximum Resistance vs Bias Votage 23 Table 8 Resolution for NTC hResistors 24 Table 9 10mV Constant Voltage Accuracy Gpechfcations 24 Table 10 Supported Sensor Configurations cccccccceceeeceeeeeeeeeeeeeeee 30 Table 11 PTC Resistor Sensor Confouration 31 Table 12 Loop 1 Heater output ranges ne 34 Table 13 Loop 2 Heater output ranges ne 35 Table 14 AC Power LUnetuses ne 38 Table 15 Keypad key TIunchons 45 Table 16 Temperature Une 47 Table 17 Control Loop Error Status Indicators 48 Table 18 Input Channel Configuration Men 52 Table 19 Control Loop Setup Menus oooocncococococonccccoconnnnccccnnnnnannnnnnnnnonccnns 55 Table 20 User Configurations Men 59 Table 21 System Configuration Mem 60 Table 22 Over Temperature Disconnect Copnfiouraton 62 Table 23 Network Configuration Men 64 Table 24 PID Table
22. Can be set to any input or to default where default is the input channel shown in the loop setup menu Range Heater range setting Table 24 PID Table Edit Menu Pressing the Esc key from this menu will abort the line entry process and return the display to the PID Table Menu above Any edits made to the line will be lost When a table index is selected all of the lines on this menu will be updated to show the selected line Any data in the selected index will be displayed on the following lines The following data can be entered into the PID zone Setpoint SP Proportional gain P Integral gain I Derivative gain D and heater range To delete a zone from the PID Table enter zero or a negative number in the setpoint field These entries will be rejected when the table is conditioned and stored in Flash memory Save the entire table by scrolling to the last line SaveTable amp Exit then press the Enter key 66 Cryo con Model 24C Front Panel Menu Operation Sensor Setup Menu The Sensor Setup menu is used to view and edit user temperature sensor data The Sensor Header Edit Menu Pressing the Sensor key from the Home Status Display accesses the Sensor Setup Menu From there the Sensor Header Edit Menu can be accessed by by scrolling to the sensor and pressing Enter Definition of a sensor requires entering configuration data on this screen followed by entering a calibration curve Sensor Header Edit Menu T
23. E 14 O e EA Ee 48 Configuration efr e aaae coh 103 SU Te EE 48 Koppelen iii 184 REAdDaACK A ee 48 EI 103 Over Temperature Disconnect Specifications mociones 36 Enable nio aa 62 186 Cryo con Model 24C OVERTEMP commande 130 SA eaa aE a aA EEEE 62 STOLU ne s E E E E P E ceaecheet farina 62 PID TADE Ask ae Eh eg 65 Mentee otra 65 ZONE tale iio 65 ZONES EE 65 Rol Vico e a ae Configuration 70 Connector iniciada 14 Deadband 70 117 131 132 O pretenders ade chia 4 Specifications 2424 west as hese A n 26 36 RG 282 ie dest EES EE Configuracion 104 Connecti eie aa a ia a 184 Specifications srine 36 EIER ek Adel MA AA Se EeEEeEEEAEEER AE 164 Mounting ahaa id AE 165 Je AA EE INtrOUCtION cion iniciada diia 106 OEI Wi A aba 105 SONS Of A E eel Calibration Cupye 67 132 Connechon ene esios 33 151 181 MultiplierTieldicocitocic rin 67 SOU MENU ui ca a 67 Table dex coincida 67 MO A NAAA 67 Type selechon 67 Sensor Calibration Cupve CRV file 77 78 File Tomat 132 LogOhms 145 Sens r Picnic ge AAA E 30 141 Shielding REhssaiiucdoersce st 99 Synchronous Elter Rue Di e EE 61 e EE 88 KI RE 90 Temperature Gensors seee nr eteren Carbon Ceramic 21 Cernox ones 21 30 78 143 144 176 177 ei EE 1 21 30 31 78 175 IRAK WEE 141 DOT Or tata id aaa 141 Gallium Arsenide eener eeen 31 Germanium Thermietor 21 Negative temperature coefflcent 67 NIG TEE 32 Platini 31 PITO
24. For a list of both factory and user sensors refer to Appendix A New user sensor types and calibration curves are added using the Sensors menu Setting a Temperature Alarm The Alarm lines are used to setup alarm conditions The Model 24C allows alarm conditions to be assigned independently to any of the input channels High temperature and low temperature alarms may be entered and enabled Note that a user selected dead band is applied to the assertion of high and low temperature alarms Alarm conditions are indicated on the front panel by the Alarm LED and various display fields They are also reported via the remote interfaces When the audible alarm is enabled a high pitched buzzer will sound when an alarm condition is asserted The Model 24C supports latched alarms These are alarms that remain asserted even after the condition that caused the alarm has been cleared To clear a latched alarm first press Alarm to view the Alarm Status Display and then press the Home key to clear Input Channel Statistics The Model 24C continuously tracks temperature history on each input channel The Input Statistics shown in this menu provides a summary of that history The channel history is reset whenever the channel is initialized and can also be reset by pressing the Enter key while the cursor is on any of the statistics lines The Accum line shows the length of time that the channel history has been accumulating It is in units of Minutes Th
25. Increase the voltage bias until a rise in temperature is noted and then reset the bias to the just previous value Bridge Range is generally set to Auto but may be set to hold a range in systems where transients due to autoranging are disruptive Fixed ranges of 1 0mA 100uA and 10uA are available The asterisk character next to the sensor resistance reading indicates that the resistance bridge is not locked This may indicate that it is still autoranging or that the sensor resistance is too high or too low for the selected voltage bias Return to ChA cfg 75 Cryo con Model 24C Basic Setup and Operation Using PTC resistor sensors The Model 24C supports all types of Positive Temperature Coefficient resistor sensors Examples include Platinum and Rhodium ChA Sample Holder E ane oe PTC Sensor Configuration lron 241 00K FS Input 500 Ohms The PTC Sensor AC Excitation ON Excitation 1mA Configuration Menu is Pd 1 66e 10W shown here 8 Return to ChA cfg The full scale input resistance and the excitation level will change depending on the type of PTC sensor selected PTC sensor excitation can be either AC or DC The Model 24Cis calibrated with AC excitation Switching to DC will introduce a DC offset that will result in temperature measurement errors When AC excitation is On the sensor excitation current is a 7 5 Hz square wave This square wave excitation generates a small noise signal Rarely this si
26. LAN IO control1 Stop temperature control LAN IO stop Read channel B input LAN IO input B tempstr 256 printf Channel B temperature is s n tempstr send compound command to input channel A and wait for it to finish LAN IO INPUT A UNIT S SENSOR 33 OPC tempstr 256 close the instrument LAN close 138 Cryo con Model 24C EU Declaration of Conformity EU Declaration of Conformity According to ISO IEC Guide 22 and EN 45014 Product Category Measurement Control and Laboratory Product Type Temperature Measuring and Control System Model Numbers Model 24C Manufacturer s Name Cryogenic Control Systems Inc Manufacturer s Address P O Box 7012 Rancho Santa Fe CA 92067 Tel 858 756 3900 Fax 858 759 3515 The before mentioned products comply with the following EU directives 89 336 EEC Council Directive of 3 May 1989 on the approximation of the laws of the Member States relating to electromagnetic compatibility 73 23 EEC Council Directive of 19 February 1973 on the harmonization of the laws of Member States relating to electrical equipment designed for use within certain voltage limits The compliance of the above mentioned product with the Directives and with the following essential requirements is hereby confirmed Emissions Immunity Safety EN 55011 1998 EN 50082 1 1997 EN 61010 1 2001 IEC 61010 1 2001 The technical files and other documentation are on file
27. LINefreq 60 50 SYSTem DRES FULL 1 2 3 SYSTem PUControl ON OFF SYSTem BAUD 9600 19200 38400 57600 115200 SYSTem DATe mm dd yyyy SYSTem TIMe hh mm ss CONFig lt ix gt NAMe name CONFig lt ix gt SAVe CONFig lt ix gt RESTore 115 Cryo con Model 24C INPut A B C D or INPut A B C D TEMPerature INPut A B C D UNITs K C F S INPut A B C D NAMe Instrument Name INPut A B C D SENPr INPut A B C D VBlas 10MV 3 0MV 1 0MV 300UV INPut A B C D BRANge Auto 1 0MA 100UA 10UA INPut A B C D ACBias On Off INPut A B C D SENsorix lt ix gt INPut A B C D BRUNIock INPut A B C D POWer INPut A B C D ALARm INPut A B C D ALARm HIGHest lt setpt gt INPut A B C D ALARm LOWEst lt setpt gt INPut A B C D ALARm DEAdband lt setpt gt INPut A B C D ALARm HIENa YES NO INPut A B C D ALARm LOENa YES NO INPut A B C D Clear INPut A B C D LTEna YES NO INPut A B C D AUDio YES NO INPut A B C D MINimum INPut A B C D MAXimum INPut A B C D VARiance INPut A B C D SLOpe INPut A B C D OFFSet INPut TIMe INPut RESet INPut A B C D TCSet LOOP 1 2 3 4 SOURce A B C D LOOP 1 2 3 4 SETPt lt setpt gt LOOP 1 2
28. The cable used is Belden 8723 This is a dual twisted pair cable with individual shields and a drain wire The shields and drain wire are connected to the connector s metal backshell in order to complete the shielding connection A four wire connection is recommended in order to eliminate errors due to lead resistance Cryogenic applications often use fine wires made from specialty metals that have low heat conduction This results in high electrical resistance and therefore large measurement errors if the four wire scheme is not used Four wire connection to diode and resistive type sensors is diagrammed below V V Four Wire Four Wire Diode Sensor Resistor Sensor Figure 8 Diode and Resistor Sensor Connections 182 Cryo con Model 24C Appendix H Rear Panel Connections Control Loop 1 Connections Rear panel Primary Heater Output Loop 1 connections are made using a three pin banana plug on the rear panel CECR a Hester Output High Heater Output Low EGND Earth Ground Table 41 Loop 1 Connections Caution The Model 24C has an automatic control on power up feature If enabled the controller will automatically begin controlling temperature whenever AC power is applied For a complete description of this function please see the Auto Ctl function in the System Functions menu section Control Loop 2 and Relay Connections Connection to the Loop 2 Output is made on th
29. XP 1K XP 1K series Thin Film Platinum RTD 1 000Q 3039 002 Cartridge Heater Silicon free 25Q 25 Watt 1 4 x 1 1 8 Temperature range to 1 600K 3039 001 Cartridge Heater Silicon free 50 50 Watt 1 4 x 1 1 8 Temperature range to 1 600K 4039 011 Pre cut Nichrome wire heater w connectors 250 4039 012 Pre cut Nichrome wire heater w connectors 500 Bulk Nichrome Heater Wire 32AWG 3039 006 Polyamide insulation 100 Table 2 Cryogenic Accessories 15 Cryo con Model 24C A Quick Start Guide to the User Interface A Quick Start Guide to the User Interface Pressing the Power key will toggle the controller s AC power on and off This key must be pressed and held for two seconds before power will toggle Pressing the Stop key will immediately disengage both control loops Pressing the Control key will engage them Use the ESC key to exit an erroneous entry Home Status Display Pressing the Home key will return the screen to the Home Display from anywhere in the sub menus The Home Display is the primary display for instrument status information The Home Status display consists of four zone quadrants Each zone has 4 lines containing 20 characters each and can be individually configured to show useful information with minimum clutter To configure zone displays press the Display key Accessing the heater setpoint To instantly access the setpoint for either control loop press the Set Pt key Configu
30. a load resistance that is too high Indicates that the control loop was disconnected by the Over Temperature Disconnect Monitor This monitor is configured by the user and functions to OTDisconn disable the heater if a specified over temperature condition exists on a selected input channel Indicates that the resistance of the heater is too low and can cause HtrShort overheating of the controller s internal circuits For Loop 1 set to a 500 load the actual resistance must be gt 400 With a 250 load selected the resistance must be gt 100 Table 17 Control Loop Error Status Indicators 48 Cryo con Model 24C Front Panel Operation Loop Bar Chart Display The Loop Bar Chart is a 50 segment bar chart that shows the measured output of a selected loop output The bar is composed of ten blocks with five segments Therefore output current can be read to an accuracy of 2 Note that the bar chart does not have a loop number indicator Some examples are Loop ON zero output Ten Loop OFF Htr Off Loop ON 50 output N Note The Model 24C uses an independent circuit to read current actually flowing through the load The heater bar graph shows this measured current If the unit is controlling temperature but the bar graph indicates zero current flow an error condition exists possibly an open heater 49 Cryo con Model 24C Front Panel Menu Operation Front Panel
31. alarm must be enabled before it can be asserted 124 Cryo con Model 24C Remote Programming Guide INPut A B C D ALARm LOENa YES NO Sets or queries the low temperature alarm enable for the specified input channel An alarm must be enabled before it can be asserted INPut A B C D ALARm LTENa YES NO Sets or queries the latched alarm enable mode When an alarm is latched it can be cleared by using the CLEar command INPut A B C D ALARm CLEar Clears any latched alarm on the selected input channel INPut A B C D ALARm AUDio YES NO Sets or queries the audio alarm enable When enabled an audio alarm will sound whenever an alarm condition is asserted INPut A B C D MINimum Queries the minimum temperature that has occurred on an input channel since the statitics were reset INPut A B C D MAXi mum Queries the maximum temperature that has occurred on an input channel since the statitics were reset INPut A B C D VARiance Queries the temperature variance that has occurred on an input channel since the statitics were reset Variance is calculated as the Standard Deviation squared INPut A B C D SLOpe Queries the input channel statistics SLOPE is the slope of the best fit straight line passing through all temperature samples that have been collected since the statitics were reset SLOPE is in units of the input channel display per Minute INPut A B C D OFFSet Queries the input channel statisti
32. and low sensitivity constant voltage will apply a high excitation current to improve measurement accuracy At low temperature where the sensor has high sensitivity and high resistance measurement errors are dominated by sensor self heating Constant voltage excitation reduces this error by reducing power dissipated in the sensor as temperature decreases Acommon source of error at ultra low temperature is sensor self heating due to DC offsets in the measurement electronics The Model 24C resistance bridge measures the actual current flowing through the sensor to actively cancel DC offsets by using a feedback loop to offset it s excitation source Ultra low temperature systems can be negatively affected by coarse steps in excitation current The Model 24C prevents this by using a step less continuously variable excitation source Positive Temperature Coefficient PTC resistor sensors including Platinum CLTS and Rhodium lron RTDs use the resistance bridge in a constant current AC mode Platinum RTD sensors use a built in DIN standard calibration curve that has been extended to 14K for cryogenic use Lower temperature use is possible with custom calibrations Cryo con Model 24C Introduction Silicon diode sensors are supported over their full temperature range by using the bridge in a DC constant current mode Thermocouple sensors are supported by using an optional thermocouple module that plugs into any of the Model 24C s input ch
33. assigns input B to user sensor 2 SENSorix 64 NAMe Returns the name string of user sensor 4 SENSorix 63 TYPe ACR sets the type of user sensor 3 to ACR NOTE Factory installed sensors are indexed from 0 to 60 User installed sensors have index values from 61 to 68 corresponding to user curves 1 through 8 142 Cryo con Model 24C Appendix A Installed Sensor Curves Sensor Curves on CD The following sensors are available on the CD supplied Cryocon S700 Cryo con S700 series Silicon diode Range 1 4 to 500K 10uA constant current excitation CryocalD3 crv Cryocal D3 Silicon diode Range 1 5 to 300K 1410 crv Scientific Instruments Inc SI 410 Silicon diode Range 1 5 to 450K Curve10 crv Lakeshore Curve 10 Silicon diode curve for DT 470 series diodes Range 1 4 to 495K Lakeshore Curve 10 Silicon diode curve for DT 670 series diodes Range 1 4 to 500K PT100385 crv Cryocon CP 100 DIN43760 or IEC751 standard Platinum RTD 100Q at 0 C Range 23 to 1020K PT1K385 crv DIN43760 or IEC751 standard Platinum RTD 1000Q at 0 C Range 23 to 1020K PT1003902 crv Platinum RTD 100Q at 0 C Temperature coefficient 0 003902 Q C Range 73K to 833K PT1K375 crv Platinum RTD 10000 at 0 C Temperature coefficient 0 00375 Q C Range 73K to 833K Chromel AuFe 7 thermocouple Range 3 to 610K Curve11 crv aufe07cr crv TCTypeE crv TCTypeK crv TCTypeT crv CX1030E1 crv Thermocouple Type E Range
34. composing commands and improves readability Purpose If the user s intent is to remotely program a Cryo con instrument with fairly simple sequences skip to the section titled Commonly Used Commands This is a simple cheat sheet format list of the commands that are most frequently used For an advanced user familiar with the SCPI programming language the section titled Remote Command Descriptions is a complete reference to all commands If you are unfamiliar with the SCPI language but it is necessary to perform advanced programming tasks SCPI is introduced in the next section For all users the section titled Debugging Tips is often helpful and the Remote Command Tree is a single page listing that shows the syntax of each command 105 Cryo con Model 24C Remote Programming Guide An Introduction to the SCPI Language SCPI is an acronym for Standard Commands for Programmable Instruments Commonly pronounced skippy it is an ASCll based instrument command language defined by the IEEE 488 2 specification and is commonly used by test and measurement instruments SCPI commands are based on a hierarchical structure also known as a tree system In this system associated commands are grouped together under a common node or root thus forming subsystems A portion the command tree for a Cryo con instrument is shown here INPut SYSTem TEMPerature BEEP UNITs ADRS VARIance LOCKout SLOPe ALARm NAMe LOOP CONFig SETPT SAVE RA
35. configuration Cryo con s external USB option is automatically configured by the instrument when it is plugged into the RS 232 port Your computer will see it as an extra COM port Use it for communications just like any other RS 232 port 104 Cryo con Model 24C Remote Programming Guide Remote Programming Guide General Overview The IEEE 488 2 SCPI remote interface language is common to all Cryo con products Since the language supports both simple and advanced functions it may initially seem complex However the use of English language keywords and a consistent tree structured architecture make it easy to read and learn Language Architecture The programming language used by all Cryo con instruments is described as follows e The industry standard SCPI language defined by the IEEE 488 2 standard is used Therefore anyone with experience in test and measurement will find it familiar e All Cryo con instruments use the same language and future instruments will continue in the same fashion Therefore your investment in system software will not be lost when a product is revised or replaced e Keywords used in commands are common English words not cryptic acronyms This makes command lines easy to read and understand even for someone that is not familiar with the instrument e The SCPI is a tree structured language where commands are divided into groups and associated commands into sub groups This architecture simplifies
36. extend future calibration intervals 101 Cryo con Model 24C Remote Operation Remote Operation Remote Interface Configuration The Model 24C has two remote interfaces The Ethernet LAN and the RS 232 There are also two external options IEEE 488 2 GPIB and USB Connection to all of these interfaces is made on the rear panel of the instrument For specifics about the connectors and cables required refer to the section on Rear Panel Connections Supported Ethernet Protocols HTTP The Model 24C s HTTP server is used to implement the instrument s embedded web server SMTP The Simple Mail Transport Protocol is used to send E mail from the Model 24C to a selected address TIMEP The Time Protocol allows a client to obtain the date and time from a host TIMEP server If a time server is available on the Local Area Network the Model 24C will periodically query it to update it s internal real time clock TCP IP UDP These ports are available for communication using an ASCII command language Ethernet Configuration Each device on an Ethernet Local Area Network must have a unique IP Address This address must be within the range of the computers you want it to communicate with The range is determined by the Subnet Mask To connect to a LAN switch or hub use a standard Category 5 patch cable To connect directly to a PC use a Category 5 crossover type patch cable The Model 24C is shipped with a default IP address of 192 168
37. from the front panel or transferred via any of the available remote interfaces New calibration curves may be generated using the CalGen feature to fit any existing diode Platinum or NTC resistor calibration curve at up to three user specified temperature points This provides an easy and effective method for obtaining higher accuracy temperature measurements without expensive sensor calibrations Data logging is performed by continuously recording to an internal 1 365 entry circular buffer Data is time stamped so that the actual time of an event can be determined Non volatile memory is used so that data will survive a power failure Input Channel Statistics The Model 24C continuously tracks temperature history independently on each input channel and provides a statistical summary that indicates the channel s minimum maximum average and standard deviation Also shown are the slope and the offset of the best fit straight line of temperature history data Alarms Visual remote and audible alarms are independently programmed to assert or clear based on high or low temperature condition or a detected sensor fault Latched alarms are asserted on an alarm condition and will remain asserted until cleared by the user Cryo con Model 24C Introduction Relays The Model 24C has two 10 Ampere dry contact relays These can be used to control a refrigerator system or other external equipment Each relay can be asserted or cleared based o
38. gt n lt entry 1 gt n lt entry N gt n An Where lt name gt is the name of the table and is a maximum of 16 ASCII characters lt entry gt is a PID entry Aline that contains only a single semicolon indicates the end of the table The format of an entry is lt Setpt gt lt P gt lt I gt lt D gt lt range gt lt Source gt n Fields are separated by a white space The entry is terminated by a new line In character lt Setpt gt lt P gt lt I gt lt D gt are floating point numbers that correspond to Setpoint Pgain Igain and Dgain lt range gt is the heater range string lt Input Channel gt is the controlling source input channel and may be ChA ChB ChC ChD or Default Note that default selects the input channel from the loop s source setting Floating point numbers may be entered with many significant digits They will be converted to 32 bit floating point which supports about six significant digits 134 Cryo con Model 24C Remote Programming Guide An example of a sixteen entry PID Table is as follows PID Test O 300 280 260 240 220 200 180 160 140 120 100 80 60 40 20 10 00 00000000022 160 150 140 130 120 HI Default HI Default HI Default HI Default HI Default HI Default MID Default MID Default MID ChB MID ChB MID ChB MID ChB LOW ChA LOW ChA LOW ChA LOW ChA Entries may be sent to the controller in any order Entries containing invalid
39. initial value for P and zero for and D This will result in stability at a temperature of the setpoint minus some constant offset Increasing the P value reduces the offset amount When P is too large the system oscillates Another pre tuning technique is to Manual control mode with some fixed value of output power When the system becomes stable at a temperature corresponding to the set heater power level a system characterization process is performed using that temperature as an initial setpoint 81 Cryo con Model 24C Basic Setup and Operation System Characterization System characterization is the process of using autotune to generate optimal PID coefficients for each setpoint over a wide range of possible setpoints The characterization process is performed once Then the setpoints and corresponding generated PID values are transferred to an internal PID table Thereafter the system is efficiently controlled using the Table control mode Autotune Setup and Execution The Autotune menu for either control loop is accessed by pressing the Auto Tune key from the Home Operate Screen Upon entry the autotune state variable is set to Idle and the P and D fields on the bottom of the display will be blank As described above various setup conditions must be met before autotune can be performed 1 The Model 24C must be in Control mode 2 Both the output power and the process temperature must be stable The user must stabi
40. is offset to match the 77K point then the gt 30K region is fit to the two points 3 Three points 300K 77K and 4 2K Two points above 30K are fit as in the selection above Then a third point is used to fit a single point in the high sensitivity region below 20K 4 One point near 4 2K This is a two point fit where the 20K point is taken from the existing calibration curve The portion of the curve above 20K is unaffected For a diode sensor a sub menu is displayed that allows the user to select the number of points desired for the CalGen fit First CalGen Menu Diode Sensor Pressing the Enter key will select curve generation with a 81 pt CalGen 300K single point near 300K Pressing the Enter key will select curve generation at two points where both points must be gt 50K 82pt CalGen Pressing the Enter key will select curve generation three points Two above 50K and one near 4 2K 83pt CalGen Pressing the Enter key will select curve generation with a single point near 4 2K 8ipt CalGen 4 2K Table 33 First CalGen Menu Diode Sensor From this screen select the desired number of points For example select 2 point This will take the display to the two point curve generator screen shown here 92 Cryo con Model 24C Basic Setup and Operation CalGen Menu 2 point Diode Sensor The exact temperature at a point near 300K is entered here 300 000 Capture Note if
41. is stable at the required temperature Next the second temperature must be entered in the same way as before 93 Cryo con Model 24C Basic Setup and Operation When both temperature points have been entered the user may select the New Curve field in order to generate the new curve This will cause the display of a menu like the one shown here CalGen New Curve Menu Sets the curve number for the generated curve Numeric entry Note User Sensor 1 only the user curves can be written Pressing the Enter key will cause the generation of a new curve The 8 Save curve will be stored at the curve number specified on line 1 Table 35 CalGen New Curve Menu From this screen the user must select the target user curve for the generated curve Finally select the Save field in order to generate the curve and store it in the selected user location Note The CalGen process may be aborted by pressing the Esc or Home key Using CalGen With Platinum and Resistor Sensors The calibration curve generation procedure for Platinum or Resistor sensors is the same as for the diode sensors described above However these curves are generated using two user specified points Therefore the selection of the number of points is not required 94 Cryo con Model 24C Basic Setup and Operation Using Thermocouple Sensors Thermocouple temperature sensors offer an extremely wide range of operation They can al
42. is the sensor units and must be Volts Ohms or Logohm Curve entries must be the sensor reading followed by the temperature in units of Kelvin Values are separated by one or more white space or tab characters The last line in the file has a single semicolon character All lines after this are rejected It is recommended that the curve back is read after downloading to ensure that the instrument parsed the file correctly This is easily done by using the Cryo con utility software s curve upload function under Operations gt Sensor Curve gt upload 145 Cryo con Model 24C Appendix B Updating Instrument Firmware Appendix B Updating Instrument Firmware Updates require the use of the Cryo con Firmware Update Utility software and a hex file containing the updated firmware These are available on the Internet O Note Updating firmware in any instrument is not entirely without risk Please only perform the procedure when some down time is available The update will abort on the detection of a hardware malfunction Also the update may change instrument features that you are currently using in a different way Factory defaults settings are restored that will erase any existing user calibration curves or PID tables Discussion Cryo con instruments have two blocks of flash type program memory In the standard configuration the Internal block contains a boot loader program and the External block contains the actual instru
43. modification or misuse operation outside of the environmental specifications for the product or improper site preparation or maintenance The design and implementation of any circuit on this product is the sole responsibility of the Buyer Cryo con does not warrant the Buyer s circuitry or malfunctions of this product that result from the Buyer s circuitry In addition Cryo con does not warrant any damage that occurs as a result of the Buyer s circuit or any defects that result from Buyer supplied products Notice Information contained in this document is subject to change without notice Cryo con makes no warranty of any kind with regard to this material including but not limited to the implied warranties of merchantability and fitness for a particular purpose Cryo con shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing performance or use of this material No part of this document may be photocopied reproduced electronically transferred or translated to another language without prior written consent Trademark Acknowledgement CalGen and Cryo Con are registered trademarks of Cryogenic Control Systems Inc All other product and company names are trademarks or trade names of their respective companies Safety The Model 24C does not contain any user serviceable parts Do not open the enclosure Do not install substitute parts or perform a
44. order to set the Instrument Event IE bit in the Status Byte STB register This can cause a service request GPIB to occur Bits in the ISE correspond to the bits in the ISR defined above 112 Cryo con Model 24C Remote Programming Guide The Standard Event Register The Standard Event Register ESR is defined by the SCPI to identify various standard events and error conditions It is queried using the Common Command ESR This register is frequently used to generate an interrupt packet or service request when various I O errors occur Bits in the ESR are defined as follows ESR Bit Lo Bits ou Bits Bitz on Ton Where Bit7 OPC Indicates Operation Complete Bit5 QE Indicates a Query Error This bit is set when a syntax error has occurred on a remote query It is often used for debugging Bit4 DE Indicates a Device Error Bit3 EE Indicates an Execution Error This bit is set when a valid command was received but could not be executed An example is attempting to edit a factory supplied calibration table Bit2 CE Indicates a Command Error This bit is set when a syntax error was detected in a remote command Bit0 PWR Indicates power is on The Standard Event Enable Register The Standard Event Enable Register ESE is defined by the SCPI as a mask register for the ESR defined above It is set and queried using the Common Command ESE Bits in this register map to the bits of the ESR
45. remote commands This menu is selected by pressing the ChA key and then setting the Sensor field to the desired thermocouple type Next select the Input Config field For cryogenic applications an offset calibration is usually done at a low temperature reference point Examples being liquid nitrogen or even liquid helium The result of the calibration is that the controller will read the correct temperature when the sensor is held at that reference Setting the Reading field to zero turns offset calibration OFF This is useful to start a new calibration Since thermocouples lose sensitivity at low temperature an offset calibration in that range will generally have little effect on the higher temperature accuracy An offset calibration is done as follows 1 Connect the controller as usual for thermocouple measurements For best accuracy be sure that ambient temperature doesn t vary 2 Allow the instrument to warm up for at least Y hour without moving or handling the sensor 3 From the instrument front panel first set the thermocouple sensor and then go to the input configuration menu 4 Establish the thermocouple device at a precisely known temperature When stable enter the desired reading in the Set Reading field and press Enter For example if the sensor is immersed in liquid nitrogen enter a value of 77 35K 5 The input temperature reading should now stabilize at the value entered Note that the Set Reading temperature is
46. temperature setting of the high temperature setpoint for the specified relay Parameter lt setpt gt is floating point numeric and is in units of the controlling input channel RELays 1 2 MODe AUTo ON OFF Set or query the relay mode Modes are Auto Relay is controlled by enabled high and low setpoints ON Relay is in manual mode and is asserted OFF Relay is in manual mode and is clear Control Relay is asserted whenever the controller is in Control mode RELays 1 2 LOWest lt setpt gt Relay Low setpoint Sets or queries the temperature setting of the low temperature setpoint for a specified relay Parameter lt setpt gt is floating point numeric and is in units of the controlling input channel RELays 1 2 HIENa YES NO Relay High Enable Sets or queries the high temperature enable for the specified relay RELays 1 2 LOENa YES NO Relay Low Enable Sets or queries the low temperature enable for the specified relay 131 Cryo con Model 24C Remote Programming Guide RELays 1 2 DEAdband lt dead band gt Sets or queries the dead band parameter This controls the amount of hysteresis that is applied before a relay is asserted or cleared Parameter lt dead band gt is floating point numeric and is in units of the controlling input channel Sensor Calibration Curve Commands The CALCUR commands are used to transfer sensor calibration curves between the instrument and the host controller Curves are ref
47. the proper switch to the right Ensure that there is only one type selected Figure 6 TETEE Next replace the plastic cover on the module The Switches thermocouple module is now ready for use Instrument Setup Instrument setup is performed as follows 1 Connect the thermocouple module to any of the available input channels 2 From the front panel go to the Input Channel Configuration menu by pressing the appropriate ChA or ChB key Next scroll down to the Sen field and select the sensor by pressing the Next key When the proper thermocouple type is displayed press the Enter key 3 Scroll down to the Input Config field and press the Enter key to display the Thermocouple Sensor Configuration Menu 4 Optionally perform the offset calibration procedure described below 5 Return to the Home screen by pressing the Home key several times 95 Cryo con Model 24C Basic Setup and Operation Offset Calibration Thermocouple devices can vary significantly from their standard curves especially at cryogenic temperatures where their sensitivity is reduced To accommodate these variations the Model 24C allows an offset calibration for individual thermocouple devices Note that device calibration do not affect the instrument s basic calibration Device calibration is performed by using the instrument s Input Configuration menu An example is shown here Alternatively calibration Set Reading 0 00K may be performed by using
48. the two DIN 6 receptacles provided Silicon diode and all resistor type sensors should be connected to the Model 24C using the four wire method It is strongly recommended that sensors be connected using shielded twisted pair wire Wires are connected as shown below and the shield should be connected to the metal back shell of the connector Excitation l Sense V Table 39 Input Connector Pin out Rea r Vi ew E 2 3 AuxPower SVDC E S00mA_ Es a SC Caution To ensure proper low noise operation cable shields should be connected to the metal back shell of the connector A metal clip is provided with the connector for this purpose Please refer to the section on shielding and grounding for further information Figure 7 Proper Assembly of the Input Connector 181 Cryo con Model 24C Appendix H Rear Panel Connections Caution Any disconnected inputs to the Model 24C should be configured to a sensor type of None This will turn the input off and prevent the high impedance pre amplifiers from drifting Note The input connectors on the Model 24C will mate with either DIN 5 or DIN 6 plugs Wiring is identical If a DIN 6 plug is used Pin 6 is not connected Do not connect to pin 3 of either connector Recommended color codes for a sensor cable are as follows Color Code Signal Pm ed Sense a Flack Senses e Table 40 Sensor Cable Color Codes
49. this name can be changed to give a better indication of the sensor type that is connected For most sensor types installation is now complete press the Home key to return to the Home Status display The exceptions are NTC resistor sensors that use constant voltage AC excitation With these types of sensors scroll down to the Bias Voltage field and select the desired constant voltage excitation level Note Only NTC resistor sensors require the selection of a Bias Voltage Once sensor configuration is complete review the section on Sensor Connections to connect the sensor to the instrument 73 Cryo con Model 24C Basic Setup and Operation Using NTC Sensors Negative Temperature Coefficient NTC resistors are often used as low temperature thermometers especially at ultra low temperature Their resistance and sensitivity increase dramatically at low temperature but their sensitivity is often relatively poor at warmer temperatures The Model 24C supports these sensors by using a constant voltage AC resistance bridge e Measurement accuracy and temperature range are improved at low temperature because sensor self heating errors are reduced or eliminated e Measurement accuracy is improved at warmer temperatures because the constant voltage circuit increases excitation power in that region e The control stability is improved in the warm region since higher excitation power reduces measurement noise e DC offs
50. when Low 100 000 enabled will be asserted when the input temperature is below this value Enable No Low temperature output enable Deadband 0 25 GE or transition band in units of the controlling input The first line of the display is an information only line that describes the state of the digital output and the current temperature on the source input channel It is used to assist in the configuration of the digital outputs Digital output status indicators are shown in the table below The deadband field sets the amount of hysteresis applied to the temperature before a digital output is set or cleared Units for this field are in the same units as the controlling input channel For example if the deadband is set to 0 25K a high temperature digital output will not assert until the current temperature exceeds the setpoint by 0 25K and will not clear until the temperature is 0 25K below the setpoint 70 Cryo con Model 24C Front Panel Menu Operation Relay is in Auto mode and is clear Relay is asserted by a high temperature condition Relay is asserted by a low temperature condition Relay is in manual mode and is asserted Relay is in manual mode and is clear Table 28 digital output Status Indicators Relay Modes are as follows Auto Relay is controlled by enabled high and low setpoints ON Relay is in manual mode and is asserted OFF Relay is in manual mode a
51. with Mr Guy Covert President and CEO As the manufacturer we declare under our sole responsibility that the above mentioned products comply with the above named directives y D Covert President Cryogenic Control Systems Inc June 10 2010 139 Cryo con Model 24C Appendix A Installed Sensor Curves Appendix A Installed Sensor Curves Factory Installed Curves The following is a list of factory installed sensors and the corresponding sensor index AAA No Sensor Used to turn the selected input channel off Cryo con 900 Cryo con 5700 series Silicon diode Range 1 4 to 500K 10uA constant current excitation Lakeshore DT 670 series Silicon diode Curve 11 Range 1 4 to 500K LS DT 670 Sang 10nA constant current excitation Lakeshore DT 470 series Silicon diode Curve 10 Range 1 4 to 500K LS DT 470 rae 10nA constant current excitation CD 12A Cryo Industries CD 12A Silicon diode Range 1 4 to 500K 10uA constant current excitation SI 410 Diode Scientific Instruments Inc 410 diode Curve Range 1 5 to 450K 10uA excitation Pt100 385 DIN43760 standard 100Q Platinum RTD Range 23 to 873K 1mA excitation PHK 385 1000Q at 0 C Platinum RTD using DIN43760 standard calibration curve Range 23 to 1023K 100A excitation PHOK 385 10KQ at 0 C Platinum RTD Temperature coefficient 0 00385 Range 23 to 873K 10uA excitation RhFe 27 1mA Rhodium lron 27Q at 0 C 1mA DC excitation 1 5 to 873K Scientific Inst
52. with detachable universal Euro Shuko line cord Options espia O Thermocouple Input Module Field installable Supports all 4039 004 thermocouple types Controller supports up to 4 modules 4001 002 IEEE 488 2 GPIB Option Field installable 4001 001 USB Option Serial Port Emulation Field installable 12 Cryo con Model 24C Preparing the controller for use Technical Assistance Troubleshooting guides and user s manuals are available on our web page at http www cryocon com Technical assistance may be also be obtained by contacting Cryo con as follows Cryogenic Control Systems Inc PO Box 7012 Rancho Santa Fe CA 92067 7012 Telephone 858 756 3900x100 FAX 858 759 3515 e mail cctechsupport cryocon com For updates to LabView drivers Cryo con utility software and product documentation go to our web site and select the Download area Current Firmware Revision Level As of July 2014 the firmware revision level for the Model 24C pic A B C series is 2 52 Instrument firmware can be updated in the field via the Relay contact 2 0A 30W A0 DA 150W LAN port Updates are available on rating the Internet Non powered 40 04 Selectable 10V or 5V Current Hardware Revision Level outputs full scale As of July 2014 the hardware 10W or 1 0W 25W or 2 5W Volt full revision level for the Model 24C Loop 2 output Volt full scale scale series is C Returning Equipment If an inst
53. 00UV Sets or queries the constant voltage mode voltage used on the specified input channel This value only applies to sensors that use constant voltage excitation They are indicated by a sensor type of ACR If this query is used with a sensor type other than ACR it will always return N A for not applicable Note that the 1 0mV setting should only be set extremely low temperature use INPut A B ACEXcite On Off Default On Applies to PTC100 and PTC1K sensors only When AC excitation is selected a square wave is used for sensor excitation This is the default and gives best accuracy In some systems the AC excitation waveform can be picked up by sensitive equipment In this case AC excitation should be turned off 123 Cryo con Model 24C Remote Programming Guide INPut A B C D Default Auto BRANge Auto 1 0MA 100UA 10UA Sets or queries the resistance bridge range This is a range hold function Normally this is set to auto so that the instrument will autorange excitation For special applications the resistance bridge may be set to a specific excitation range INPut A B C D SENSor lt ix gt Sets or queries the sensor index number lt ix gt is taken from Appendix A INPut A B C D SENSPwr Queries the sensor power dissipation in Watts Response is in scientific notation INPut A B C D BRUN Tock Queries the bridge unlock indicator Returns a space character if the bridge is locked or an asterisk character
54. 025 0 33 0 96 2377 1303 00 0 47 3652 5388 00 80 00 1032 0 49 0 95 2390 1331 00 0 46 3706 5624 00 60 00 1042 0 84 0 94 2403 1359 00 0 45 3762 5877 00 40 00 1058 1 50 0 93 2417 1388 00 0 44 3821 6149 00 20 00 1101 4 08 0 92 2430 1417 00 0 43 3883 6439 00 15 00 1127 7 20 0 91 2445 1449 00 0 42 3947 6751 00 10 00 1178 15 40 0 90 2459 1481 00 0 41 4014 7086 00 9 00 1195 18 80 0 89 2474 1514 00 0 40 4085 7447 00 8 00 1216 23 60 0 88 2489 1548 00 0 39 4160 7837 00 7 00 1243 30 50 0 87 2505 1583 00 0 38 4238 8259 00 6 00 1277 40 90 0 86 2520 1621 00 0 37 4321 8715 00 5 00 1325 57 80 0 85 2537 1658 00 0 36 4408 9212 00 4 50 1356 70 50 0 84 2553 1697 00 0 35 4500 9753 00 4 30 1371 76 90 0 83 2570 1738 00 0 34 4598 10343 00 4 20 1378 80 40 0 82 2588 1781 00 0 33 4701 10989 00 4 00 1395 88 20 0 81 2605 1824 00 0 32 4811 11699 00 3 90 1404 92 60 0 80 2624 1869 00 0 31 4928 12481 00 3 80 1413 97 30 0 79 2642 1917 00 0 30 5053 13345 00 3 70 1423 102 30 0 78 2661 1966 00 0 29 5186 14303 00 3 60 1433 107 70 0 77 2681 2016 00 0 28 5329 15369 00 3 50 1444 113 70 0 76 2701 2070 00 0 27 5483 16562 00 3 40 1455 120 10 0 75 2722 2124 00 0 26 5648 17901 00 3 30 1467 127 20 0 74 2743 2182 00 0 25 5827 19412 00 3 20 1480 134 80 0 73 2765 2242 00 0 24 6022 21126 00 3 10 1493 143 20 0 72 2787 2304 00 0 23 6233 23081 00 3 00 1508 152 40 0 71 2810 2368 00 0 22 6464 25325 00 2 90 1523 162 70 0 70 2834
55. 05 29072 628083 temperature operation Features include 0 1 13114 145658 interchangeability and operation in high 0 2 6996 30943 magnetic fields 0 3 5053 13345 The Model 24C will support the R500 0 5 3503 4760 down to lt 100mK Please refer to the 1 2327 1203 section titled Voltage Bias Selection 1 4 1985 660 6 2 1723 343 5 3 1508 152 4 4 2 1378 80 4 T K Ohms QIK 6 1277 40 9 0 05 29072 628083 10 1178 15 4 0 1 13114 145658 20 1101 4 08 0 2 6996 30943 30 1053 4 0 0 3 5053 13345 40 1009 35 0 5 3503 4760 1 2327 1203 1 4 1985 660 6 2 1723 343 5 3 1508 152 4 4 2 1378 80 4 6 1277 40 9 10 1178 15 4 20 1101 4 08 30 1053 4 0 40 1009 3 5 178 Cryo con Model 24C Appendix G Sensor Data Tables An external thermocouple module is required K uv uV K 3 2 6457 7 0 74 K uV uVIK 10 6448 5 2 01 3 2 9834 9 1 59 10 5 6447 4 2 12 4 2 9833 2 09 20 6417 8 4 15 10 9813 3 4 66 30 6365 1 6 39 20 9747 8 51 40 6290 8 61 30 9643 8 12 1 50 6193 3 10 7 40 9505 5 15 5 75 5862 9 15 6 50 9334 2 18 7 100 5417 6 19 9 75 8777 7 256 150 4225 5 27 5 100 8063 4 31 4 200 2692 8 33 5 150 6238 1 41 2 250 897 6 38 200 3967 4 49 3 273 15 0 39 4 250 1328 7 56 300 1075 3 40 6 273 15 0 58 5 350 3135 8 41 5 300
56. 11 2 26 50 1 07188 1 46 77 35 1 02511 1 69 100 0 98615 1 85 150 0 88988 2 03 me S de Ci od 200 0 78311 2 17 T K Volts mV K 250 0 67124 2 28 1 4 1 63864 36 56 300 0 55674 2 36 4 2 1 53960 33 91 355 0 42759 2 33 10 1 36317 26 04 400 0 32161 2 38 20 1 17370 11 34 450 0 20231 2 37 30 1 10343 3 12 500 0 09077 2 12 50 1 07399 1 46 77 35 1 02511 1 69 100 0 98740 1 85 150 0 89011 2 03 200 0 78272 2 17 250 0 67085 2 28 300 0 55665 2 36 355 0 42759 2 33 400 0 32161 2 38 450 0 20231 2 37 500 0 09077 2 12 Cryo con Model 24C Appendix G Sensor Data Tables T K Volts mV K T K Volts mV K 1 4 1 71488 10 54 1 4 1 6981 13 1 4 2 1 64660 32 13 4 2 1 6260 33 6 10 1 39562 35 28 10 1 4201 28 7 20 1 17592 20 43 20 1 2144 17 6 30 1 10136 1 75 30 1 1070 2 34 50 1 06957 1 59 50 1 0705 1 75 77 35 1 14905 1 72 77 35 1 0203 1 92 100 0 98322 1 82 100 0 9755 2 04 150 0 88603 2 00 150 0 8687 2 19 200 0 78059 2 14 200 0 7555 2 31 250 0 67023 2 23 250 0 6384 2 37 300 0 55672 2 28 300 0 5189 2 4 350 0 44105 2 32 350 0 3978 2 44 400 0 32319 2 36 400 0 2746 2 49 450 0 20429 2 38 450 0 1499 2 46 475 0 0906 2 22 1 4 1 64429 12 49 4 2 1 57848 31 59 10 1 38373 26 84 20 1 19775 15 63 30 1 10624 1 96 50 1 07310 1 61 77 35 1 02759 1 73 100 0 98
57. 1325 01 1356 30 1394 87 1403 69 1412 95 1422 68 1432 91 1443 68 1455 05 1467 06 1479 78 1493 26 1507 58 1522 82 1539 09 1556 48 1575 12 1595 16 1616 77 1640 15 1665 53 1693 20 1723 48 1757 83 1793 33 1832 94 1877 43 1927 75 1985 13 2051 19 2128 07 2218 67 2327 06 2339 09 2351 35 2363 86 2376 63 2389 66 2402 97 2416 56 2430 44 2444 61 Ohms K A 7 15 19 24 30 41 58 70 88 93 97 102 108 114 120 127 135 143 152 163 174 186 200 216 234 254 277 303 343 355 396 445 503 574 661 769 906 1084 1203 1226 1251 1277 1303 1331 1359 1388 1417 1449 Temp K Ohms 0 90 0 89 0 88 0 87 0 86 0 85 0 84 0 83 0 82 0 81 0 80 0 79 0 78 0 77 0 76 0 75 0 74 0 73 0 72 0 71 0 70 0 69 0 68 0 67 0 66 0 65 0 64 0 63 0 62 0 61 0 60 0 59 0 58 0 57 0 56 0 55 0 54 0 53 0 52 0 51 0 50 0 49 0 48 0 47 0 46 2459 10 2473 91 2489 05 2504 53 2520 36 2536 57 2553 15 2570 12 2587 50 2605 31 2623 55 2642 24 2661 41 2681 07 2701 23 2721 93 2743 17 2764 99 2787 41 2810 45 2834 13 2858 49 2883 56 2909 36 2935 94 2963 32 2991 54 3020 65 3050 68 3081 68 3113 70 3146 79 3181 01 3216 41 3253 06 3291 02 3330 37 3371 19 3413 56 3457 57 3503 33 3550 93 3600 49 3652 13 3706 01 Ohms K 1481 1514 1548 1583 1621 1658 1697 1738 1781 1824 1869 1917 1966 2016 2070 2124 21
58. 152 Cryo con Model 24C Appendix C Troubleshooting Guide Autotune indicates a status Autotune will only abort if the control loops are not engaged or there is of Abort or Fail an invalid temperature reading on the control input channel If it cannot generate a solution because of issues in the system dynamics it will indicate a status of Fail Autotune times out and Extend the Display Filter time constant to reduce system level noise does not generate effective and try autotune again The display filter is described in the System PID parameters Functions Menu section Systems using diode type sensors above 50K will usually require a 4 or 8 second time constant This setting may be returned to any desired value once tuning is complete Switch to the lowest possible heater range that will control at the target setpoint Try autotuning in the PI mode instead of PID Most cryogenic systems do not benefit from the D term If a Cryo cooler is being used set the controller s cryocooler filter to Input mode This may be returned to Off or Cancel mode once tuning is complete Experiment with the DeltaP parameter Increasing it often improves autotune success Temperature Measurement Errors Symptom Je co O Noise on temperature Possible causes measurements 1 Excessive noise pickup especially AC power line noise Check your wiring and shielding Sensors must be floating so check that there is no cont
59. 20VAC USA Line Cord 04 0310 or universal Euro cord Q Certificate of Calibration Verify the AC Power Line Voltage Selection The AC power line voltage is set to the proper value for your country when the controller is shipped from the factory Change the voltage setting if it is not correct The settings are 100 120 220 or 240 VAC For 230 VAC operation use the 240 VAC setting On the rear panel of the instrument the AC voltage selection is on the power entry module If the setting is incorrect please refer to section Fuse Replacement and Voltage Selection to change it Cryo con Model 24C Preparing the controller for use Apply Power to the Controller Connect the power cord and turn the controller on by pressing the Power key for a minimum of 2 Seconds The front panel will show a Power Up display with the model number and firmware revision Cryogenic Control Systems Inc Model 24C SN 209999 Rev 1 23B While the Power Up display 1p 492 168 1 5 Static Port 5000 is shown the controller is MAC 00 50 c2 6f 40 3E H _ Calibration Testing NVRAM Testing performing a self test Device Name NewCryocon Connecting procedure that verifies the GPIB Adrs 012 RS232 9600 proper function of internal Status Self Test data and program memories remote interfaces and input output channels If an error is detected during this process the controller will freeze operation with an error message display In this case turn t
60. 23 00 0 62573 270 00 1 03156 74 00 1 13841 22 00 0 63716 265 00 1 03327 73 00 1 16246 21 00 0 64855 260 00 1 03498 72 00 1 18193 20 00 0 65992 255 00 1 03669 71 00 1 19816 19 00 0 67124 250 00 1 03839 70 00 1 21325 18 00 0 68253 245 00 1 04010 69 00 1 22816 17 00 0 69379 240 00 1 04179 68 00 1 24342 16 00 0 70503 235 00 1 04349 67 00 1 25932 15 00 0 71624 230 00 1 04518 66 00 1 27621 14 00 0 72743 225 00 1 04687 65 00 1 29401 13 00 0 73861 220 00 1 04856 64 00 1 31277 12 00 0 74978 215 00 1 05024 63 00 1 33317 11 00 0 76094 210 00 1 05192 62 00 1 35568 10 00 0 77205 205 00 1 05360 61 00 1 37998 9 00 0 78311 200 00 1 05528 60 00 1 40827 8 00 0 79412 195 00 1 05696 59 00 1 44098 7 00 0 80508 190 00 1 05863 58 00 1 47740 6 00 0 81599 185 00 1 06029 57 00 1 51590 5 00 0 82680 180 00 1 06196 56 00 1 55483 4 00 0 83754 175 00 1 06362 55 00 1 59108 3 00 0 84818 170 00 1 06528 54 00 1 62255 2 00 0 85874 165 00 1 06693 53 00 1 64342 1 00 160 Cryo con Model 24C Appendix E Sensor Data Cryo con R500 Ruthenium Oxide Sensor The Cryo con R500 with 10 A DC excitation Temp K Ohms 20 00 15 00 10 00 9 00 8 00 7 00 6 00 5 00 4 50 4 00 3 90 3 80 3 70 3 60 3 50 3 40 3 30 3 20 3 10 3 00 2 90 2 80 2 70 2 60 2 50 2 40 2 30 2 20 2 10 2 00 1 90 1 80 1 70 1 60 1 50 1 40 1 30 1 20 1 10 1 00 0 99 0 98 0 97 0 96 0 95 0 94 0 93 0 92 0 91 1100 75 1127 06 1178 49 1195 31 1216 12 1242 56 1277 29
61. 2436 00 0 21 6717 27920 00 2 80 1539 173 90 0 69 2858 2507 00 0 20 6996 30943 00 2 70 1556 186 40 0 68 2884 2580 00 0 19 7305 34493 00 2 60 1575 200 40 0 67 2909 2658 00 0 18 7650 38706 00 2 50 1595 216 10 0 66 2936 2738 00 0 17 8037 43758 00 2 40 1617 233 80 0 65 2963 2822 00 0 16 8475 49892 00 2 30 1640 253 80 0 64 2992 2911 00 0 15 8974 57444 00 2 20 1666 276 70 0 63 3021 3003 00 0 14 9548 66902 00 2 10 1693 302 80 0 62 3051 3100 00 0 13 10217 78978 00 2 00 1723 343 50 0 61 3082 3202 00 0 12 11007 94764 00 1 90 1758 355 00 0 60 3114 3309 00 0 11 11955 116005 00 1 80 1793 396 10 0 59 3147 3422 00 0 10 13115 145658 00 1 70 1833 444 90 0 58 3181 3540 00 0 09 14571 189096 00 1 60 1877 503 20 0 57 3216 3665 00 0 08 16462 257192 00 1 50 1928 573 80 0 56 3253 3796 00 0 07 19034 375766 00 1 40 1985 660 60 0 55 3291 3935 00 0 06 22792 628083 00 1 30 2051 768 80 0 54 3330 4082 00 0 05 29073 1 20 2128 906 00 0 53 3371 4237 00 1 10 2219 1083 90 0 52 3414 4401 00 1 00 2327 1203 00 0 51 3458 4576 00 0 99 2339 1226 00 0 50 3503 4760 00 162 Cryo con Model 24C Appendix E Sensor Data Sensor Packages The SM and CP Sensor Packages The S900 SM is mounted in a rugged surface mounted package This compact package features a low thermal mass and is easy to install Package material is gold plated OHFC copper on an Alumina substrate Solder limits the temperature range to 400K Leads are 3 inc
62. 3 2 to 1273K Thermocouple Type K Range 3 2 to 1643K Thermocouple Type T Range 3 2 to 673K Cernox CX1030 example curve Range 4 to 325K User Calibration Curve File Format Sensor calibration curves may be sent to any Cryo con instrument using a properly formatted text file This file has the extension crv It consists of a header block lines of curve data and is terminated by a single semicolon character The header consists of four lines as follows Sensor Name Sensor name string Sensor Type Enumeration Multiplier Signed numeric Units Units of calibration curve OHMS VOLTS LOGOHM The Sensor Name string can be up to 15 characters and is used to identify the individual sensor curve When downloaded to a Cryo con instrument this name appears in the sensor selection menu of the embedded web server and will appear on all sensor selection fields on the front panel The Sensor Type Enumeration identifies the required input configuration of the input channel For the Model 24C selections are DIODE PTC100 PTC1K NTC10uA TC70 NONE and ACR These configurations are described in the section titled Supported Sensor Configurations 143 Cryo con Model 24C Appendix A Installed Sensor Curves The Multiplier field is a signed decimal number that identifies the sensor s temperature coefficient and curve multiplier Generally for Negative Temperature Coefficient NTC sensors the value of the multiplier is 1
63. 30 392 0 065 176 Cryo con Model 24C Appendix G Sensor Data Tables T K Ohms QIK 4 2 5979 4 2225 3 6 3577 5 794 30 10 1927 2 214 11 20 938 93 46 553 30 629 90 20 613 40 474 89 11 663 50 381 42 7 490 77 35 248 66 3 150 100 193 29 1 899 150 129 60 0 854 200 97 626 0 477 250 78 723 0 299 300 66 441 0 201 350 57 955 0 143 400 51 815 0 106 420 49 819 0 094 T K Ohms Qik T K Ohms QIK 1 4 26566 48449 20 6157 5 480 08 2 11844 11916 30 3319 7 165 61 3 5733 4 3042 4 40 2167 6 79 551 4 2 3507 2 1120 8 50 1565 3 45 401 6 2252 9 432 14 77 35 836 52 15 398 10 1313 5 128 58 100 581 14 8 213 20 692 81 30 871 150 328 75 3 057 30 482 88 14 373 200 220 93 1 506 40 373 11 8 392 250 163 73 0 863 50 305 19 5 507 300 129 39 0 545 77 35 205 67 2 412 350 106 98 0 368 100 162 81 1 488 400 91 463 0 261 150 112 05 0 693 420 86 550 0 231 200 85 800 0 397 250 69 931 0 253 300 59 467 0 173 350 52 142 0 124 400 46 782 0 093 420 45 030 0 089 177 Cryo con Model 24C Appendix G Sensor Data Tables Ruthenium Oxide Cryo con R500 The R500 Ruthenium Oxide temperature T K Ohms QIK sensor is designed primarily for ultra low 0
64. 4 Sensor selechon 53 oh RH ER 26 102 Sensor unt 53 123 A A E 64 102 QA TN AAA oben aa go Ae 26 InputsstatiSticS sc nec acacawa page eae a 53 Patch Cable icnctcucin pinnien 102 184 Temperature biestor eee 53 OMT EE 102 Vandal a 53 Subnet MASK cimas 64 Units Selection oros 53 TOP iiini n 4 6 26 64 102 A 47 TIME do lt EE K depnlawy 47 Blees dee 4 6 26 64 102 INPUT commande 123 Factory Defaults cota aida Input Protections i ici di 33 E A hue deeg i 19 Instrument Calbratton eeren eu Calibration Irterval eee eeeeeeee eee 101 Revision level cocina ic 8 Calibration Genlces cece cette eee 101 Update ate eee 6 ProCedures nt esa d ene E 101 Firmware eu KEE IN 13 CONTROL key Firmware Update Uli POWER key EWut lttv exe ee Remote LED Introduction STOP key Front Pane l LabView drivers AC power key LCD display Alarm LED Loop 1 ChA key Connection Control LED Connector ENTER key Load resistance Enumeration fields Safe Operating Area ESC Keeseren awed le Lia idas HOME key cositas Specifications Keypad keys OOD Rice LM creat o id Remote EI deed ENEE n Range 3 uri ieaie deE ERR trees 35 Grounding ground Ioop no 99 Eelere EE 35 Hardware Revision Level 13 LOOP commande cece ee eee eeeeeeeeeeeees 126 Home Status Display A0 Loop Stats iaa EEN US OO cita eds OT DISCONM EE 48 Add iii iria 120 SHtr Offi neniani iesirea enna aa e ai 48 al CAR O E e a
65. 5 crossover patch cable is being used where a Category 5 patch cable should be used or visa versa The TCP settings between the monitor and the PC are incompatible Review the network configuration section PC Client software not configured to use TCP Data Socket 5000 Debugging tip Cryo con utility software can be used to talk to the monitor over the LAN Data Socket port using the terminal mode All command and response strings are displayed Since the software provides the proper interface setup it is a good way to establish initial connection 155 Cryo con Model 24C Appendix C Troubleshooting Guide General problems Symptom Controller periodically Generally caused by low AC line voltage Check the AC voltage and resets or resets when ensure that it matches the instrument s voltage selection Control key is pressed AC line voltage selection is described in the Fuse Replacement and Voltage Selection section Complete failure Possible cause 1 Blown fuse Check line voltage selection before installing new fuses Review the Fuse Replacement and Voltage Selection section Rack mounted instruments Screws were used in the rack mount shelf that are too long and have penetrated the internal circuit board of the controller 156 Cryo con Model 24C Appendix D Tuning Control Loops Appendix D Tuning Control Loops Introduction Tuning PID loops to maintain high accuracy control can be a laborious
66. 697 1 85 150 0 88911 2 05 200 0 78372 2 16 250 0 67346 2 24 300 0 55964 2 30 350 0 44337 2 34 400 0 32584 2 36 450 0 20676 2 39 500 0 09068 2 12 174 Cryo con Model 24C Appendix G Sensor Data Tables Platinum RTD Platinum RTD sensors feature high stability low magnetic field dependence and excellent interchangeability They conform to the DIN43760 standard curve T K Ohms QIK 20 2 2913 0 085 30 3 6596 0 191 50 9 3865 0 360 77 35 20 380 0 423 100 29 989 0 423 150 50 788 0 409 200 71 011 0 400 250 90 845 0 393 300 110 354 0 387 400 148 640 0 383 500 185 668 0 378 600 221 535 0 372 700 256 243 0 366 800 289 789 0 360 900 324 302 0 318 1123 390 47 0 293 Rhodium iron Rhodium lron sensors feature high stability low magnetic field dependence and reasonable interchangeability The Model 24C supports them with 1 0mA Constant Current AC excitation T K Ohms QIK 1 4 1 5204 0 178 4 2 1 9577 0 135 10 2 5634 0 081 20 3 1632 0 046 30 3 5786 0 040 50 4 5902 0 064 77 4 6 8341 0 096 100 9 1375 0 106 150 14 463 0 105 200 19 641 0 102 250 24 686 0 101 300 29 697 0 101 350 34 731 0 101 400 39 824 0 103 Cryogenic Linear Temperature Sensor CLTS CLTS sensors are inexpensive and offer excellent interchangeability The Model 24C supports them with 100uA C
67. 82 2242 2304 2368 2436 2507 2580 2658 2738 2822 2911 3003 3100 3202 3309 3422 3540 3665 3796 3935 4082 4237 4401 4576 4760 4956 5164 5388 5624 Temp K Ohms 0 45 0 44 0 43 0 42 0 41 0 40 0 39 0 38 0 37 0 36 0 35 0 34 0 33 0 32 0 31 0 30 0 29 0 28 0 27 0 26 0 25 0 24 0 23 0 22 0 21 0 20 0 19 0 18 0 17 0 16 0 15 0 14 0 13 0 12 0 11 0 10 0 09 0 08 0 07 0 06 0 05 3762 25 3821 02 3882 51 3946 90 4014 41 4085 27 4159 74 4238 11 4320 70 4407 85 4499 97 4597 50 4700 93 4810 82 4927 81 5052 62 5186 07 5329 10 5482 79 5648 41 5827 42 6021 54 6232 80 6463 61 6716 86 6996 06 7305 49 7650 42 8037 48 8475 06 8973 98 9548 42 10217 44 11007 22 11954 86 13114 91 14571 49 16462 45 19034 37 22792 03 29072 86 Ohms K 5877 6149 6439 6751 7086 7447 7837 8259 8715 9212 9753 10343 10989 11699 12481 13345 14303 15369 16562 17901 19412 21126 23081 25325 27920 30943 34493 38706 43758 49892 57444 66902 78978 94764 116005 145658 189096 257192 375766 628083 161 Cryo con Model 24C Appendix E Sensor Data Cryo con R400 Ruthenium Oxide Sensor The Cryo con R400 with 100uV AC excitation Temp K Ohms Ohms K Temp K Ohms Ohms K Temp K Ohms Ohms K 300 00 1000 0 08 0 98 2351 1251 00 0 49 3551 4956 00 200 00 1008 0 13 0 97 2364 1277 00 0 48 3600 5164 00 100 00 1
68. 9865 9950 0050 0144 0241 0325 0420 0506 0587 0673 0753 0842 0870 0904 0941 0974 TOLL 1054 1108 1238 1650 2070 2290 SC 2 k k k k a k A A k A k A AS A AA A AA NO E EE E Du A A OO A OO Temp K 260 250 240 230 220 210 200 190 180 170 160 150 140 130 120 110 100 9D 90 85 80 75 70 65 60 55 50 45 40 38 36 34 32 30 28 26 24 22 20 19 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 Volts 1 1 1 2510 2720 2950 1 3280 1 3650 1 4150 1 4700 5270 5750 5990 6230 6540 6670 1 6840 1 7080 1 7310 1 7500 7690 7850 7970 8000 1 8090 1 8160 1 8210 1 8270 1 8340 8390 8460 8520 8560 1 8590 8630 8660 RPNNNNOYO O Uds ds ds s 0101010 J JO 00010 O k NO 010 I Temp K 0000 0000 0000 0000 0000 0000 0000 0000 0000 5000 0000 5000 0000 5000 0000 5000 0000 5000 0000 7500 5000 2500 0000 7500 5000 2500 0000 7500 5000 2500 0000 7500 5000 159 Cryo con Model 24C Appe
69. CalGen has not been used on this channel before the word Capture will appear Otherwise the last captured sensor reading will appear Pressing the Enter key will capture the existing unit reading and BUnit 0 98257V associate it with the 300K point The value will be displayed on line 1 above 77 000 Capture The exact temperature at a point near 77K is entered here Pressing the Enter key will capture the existing unit reading and BUnit 1 28257V associate it with the 77K point The value will be displayed on line 3 above New Curve Pressing the Enter key will initiate the generation of a new curve Table 34 CalGen Menu 2 point Diode Sensor The two temperature points one near 300K and the other near 77K may be entered in any order To enter the 300K point change the field 300 000 to the exact required temperature Then allow the temperature measurement to stabilize When the measurement is stable select the Capture field next to the temperature field This will cause the Model 24C to capture the sensor reading and associate it with the specified temperature When a sensor reading is captured the actual reading will be displayed in place of the word Capture Note that the user may capture a new reading by selecting this field again even if it already contains a reading The Unit field of this screen will display the actual sensor reading in real time This will allow the user to determine when the unit
70. DEE 81 SA ele 17 45 55 66 126 O DEE 82 Setpoint sii ia is e 55 CALCUR commande 132 Setpoint doo ae 51 Cala 22 33 52 54 91 Sh t d WN EE 34 Configuration Scripts eneee 167 Source selechon eerren 56 Example msr anan r a a e aiu nio 170 RE Lee 19 AMES Ee E 6 167 168 Table control mode 35 57 65 Control AA A enh adse Table index selection esenee 57 Autotine ee eege Atenas ee ER 35 Temperature ramp 127 AUNING siioni anaiai 80 157 Temperature zones coocccccoccccnoccconnncnonccnnnnnnono conos 35 Control modes coococoncccccocccconcccnoncconancnnnncnanannnnnnno 57 TUNING DEE 157 Control type selechon ee TE e veel Control Ivpes 126 Synchronous Eiter 88 Default EA 11 Synchronous subtraction 88 Derivative goain 56 Thermal signature 88 A a eae ee 55 56 Cubic Spline mterpolaton eeen 2 IRC Re Le Un Te voice Buffer 63 Clearing 137 Count 137 FORM Alizee ergeet aeaii ia 137 Interval 63 137 SE Le le DEE 137 State 63 137 BIEN Resoluton 61 122 Cryo con Model 24C Index TiMe coNSt bici 61 Input Chalino nas Enclos Bou ds Alarmienable moises 124 DIMENSIONS ice iii ita ide 26 Alarm outpute eeren eeererrn nenene 36 Rack mount Kn 14 Alarm statuss ni o 124 Specifications sna antrad it Mai o AER 38 Audible aarm 36 We Estos aaa 26 Characteristics ui e 30 O A AAA a deet 14 Connections aida 184 Display resolutton eneee 47 Factory Detaults ee 102 AA EeEE EENS 47 Gateway inicias ion 6
71. Ds Carbon Glass etc This effectively cancels most of the measurement noise and allows effective use of PID control Voltage mode sensors which include diodes and thermocouples cannot benefit from ratiometric measurement therefore PI control is recommended It is a very common mistake to attempt PID control using a diode sensor above 70K This is the least sensitive region of the sensor so measurement noise is very high Pl control is recommended Below about 20K the sensitivity of the diode increases significantly and PID control may be used effectively Pre Tuning and System Stability Before autotuning can be initiated by the controller the system must be stable in terms of both temperature and heater output power This requires the user to perform a basic pre tuning operation before attempting the first autotune The goal of pre tuning is to stabilize the process at a temperature near the desired setpoint so that the tuning algorithm can use this as a baseline to model the process Cryogenic systems will usually require different PID values at different setpoint temperatures Therefore the pre tuning process should result in a temperature near the desired setpoint Pre tuning does NOT require that the user establish stable control at the target setpoint This is the job of the autotuning algorithm and is much more difficult than the stability required by pre tuning One method of pre tuning is to use PID control with a small
72. E Sensor Data 159 Cryo con S700 Silicon Diode ee ceeeeeeeeeneeeeeeeeenneeeeeeeeeteeeeeeeeeaeees 159 Cryo con S900 Silicon Diode perir icer ne aara NE ARANE 160 Cryo con R500 Ruthenium Oxide Gensor ooooccccccccoocccccccononcccncncnnnonnnns 161 Cryo con R400 Ruthenium Oxide Gensor oooocccccccncocccccccononcccncnnncnnnnnns 162 Sensor Packages ii ains 163 Appendix F Configuration Gcripts 167 Script File Structure eni a a aaa 167 SChipt File EXaMple 0 seeded aa Ee Eege ed 170 Appendix G Sensor Data Tables nnne 173 SUNCOM Diode EEN 173 Platinum RY Diese da ae dd ade 175 Elle ell Tu De EE 175 Cryogenic Linear Temperature Sensor CLT 175 COMOX Sege ideada 176 R theni m xide A 178 Cryo con Model 24C Appendix H Rear Panel Connections ccccccccceeeeeeeeeeeeeeeeeeeeeeeaeaeees 181 Sensor Connechons cece cece cece eeeeeeeeeeeeeeceeeceeeeeeeeeeeeteenesecseneneeeeeees 181 Control Loop 1 Connections ceccceeceeeeeeeeeeeeeetteeeeeeneeeeeeeees 183 Control Loop 2 and Relay Connections ccceceeeeesteeeeeeeeeeeeees 183 Ethernet LAN Connection sssssssssserieserirrissssrinnnrenranincitnnnennnsennnnennnt 184 IEEE 488 2 COMNECtIONS occoccccccccninnnonononnoncncnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnns 184 RS 232 ele ele 184 ue E EE 185 Index of Figures Figure 1 4122 030 Rack Mount kt 9 Figure 2 4034 032 Rack Mount kt 10 Figure 3 Model 24C Rear Panel Layout 37 Figure
73. E register enables the corresponding bit in the SEV register A zero disables the bit The ESE Query returns the current contents of the ESE register ESR The ESR query returns the contents of the Standard Event SEV status register OPC The OPC command causes the instrument to set the operation complete bit in the Standard Event SEV status register when all pending device operations have finished The OPC Query places an ASCII 1 in the output queue when all pending device operations have completed IDN The IDN Query causes the instrument to identify itself The Model 24C will return the following string Cryo con 24C lt serial number gt lt firmware revision gt Where lt serial number gt is the unit s serial number and lt firmware revision gt is the revision level of the unit s firmware RST Reset the controller This results in a hardware reset in the Model 24C The reset sequence takes about 15 seconds to complete During that time the instrument is not accessible over any remote interface The RST command sets the Model 24C to it s last power up default setting SRE The SRE command sets the Status Byte Enable SRE Register bits The SRE Register contains a bit mask for the bits to be enabled in the Status Byte STB Register A one in the SRE register will enable the corresponding bit in the STB register A zero will disable the bit The SRE Query returns the current contents of the SRE register
74. Edit Men 66 Table 25 Sensor Setup Men 67 Table 26 Calibration Curve Men 68 Table 27 Auto Tune Men 69 Table 28 digital output Status Indicators eee eeneeeeeeeeeeeeeeeeeeeeetees 71 Table 29 Digital Output MOdeS oooocccoooccccncconoccccnccnnnancnoncnnnnnn cnn nnnnnna conan 71 Table 30 Recommended Sensor Configuration Data 78 Table 31 Autotune Men 83 Table 323Autoftune States TT 84 Table 33 First CalGen Menu Diode Sensor ooccocinccccccccnccccnncccnnnnncccnnncnnns 92 Table 34 CalGen Menu 2 point Diode Sensol ccccccceeeeeeeeeteeeeeeees 93 Table 35 CalGen New Curve Men 94 Table 36 Thermocouple Polantes 97 Table 37 GPIB Host Setup Darameters 103 Table 38 BB Package SpecificatiONS ooooocccnnnoncccnnnnnocccnnccccnnnnnnnnnnanananon 164 Table 39 Input Connector PiN QUt ooooonnnnncncccconnnnnonocococnononnnoconanonononccnnnn 181 Table 40 Sensor Cable Color Code 182 Table 41 Loop 1 Connections cccceceeeeeeeeeeeeeceeeeeeeeeeeeeeeeesaaaeeeeeeeeees 183 Table 42 Loop 2 and Digital Output Connechons eee 183 Table 43 RS 232 DB 9 Connector Pimnout 184 vi Cryo con Model 24C Introduction Introduction The Model 24C is a four input four control loop cryogenic temperature controller designed for general purpose laboratory and industrial use Each input is independent and capable of temperature measurement to lt 100mK with an appropriate temperature sensor The Model 24C supports vir
75. Enter to go to the Over Temperature Disconnect FW Rev 1 01A Displays the firmware revision level and hardware revision letter Power Up Mode Off for normal operation On to engage Pwr Up In Ctl the control loops 10 seconds after power has been turned on AC Line 60Hz AC line frequency Select 50 or 60Hz Table 21 System Configuration Menu 60 Cryo con Model 24C Front Panel Menu Operation Display Time Constant Enumeration Default 2 Seconds The Display TC field is used to set the display time constant This is an enumeration field that sets the time constant used for all temperature displays Choices are 0 5 1 0 2 0 4 0 8 0 16 0 32 0 and 64 Seconds The time constant selected is applied to all channels and is used to smooth data in noisy environments The filtering only applies to displayed data it is not used by the control loops Display Resolution Enumeration Default 3 The Display Resolution line Display Res is used to set the temperature resolution of the front panel display Settings of 1 2 or 3 will fix the number of digits to the right of the decimal point to the specified value A setting of FULL will left justify the display to show maximum resolution possible Note that the Display Resolution setting only formats the display as a user convenience The internal resolution of the Model 24C is not affected by this setting Synchronous Filter Configuration Numeric Entry Default 7 The Synchronous Fil
76. Large values of DeltaP will allow the use of large heater power swings but this may also drive the process into non linear operation which also corrupts the tuning result Worse it may allow the application of too much heater power which causes an over temperature condition Experience indicates that most cryogenic systems autotune properly using a DeltaP of 5 whereas a noisy system requires 10 or more Acommon example of a noisy cryogenic system is one where a Silicon diode sensor is used with a setpoint near room temperature 80 Cryo con Model 24C Basic Setup and Operation System Noise and Tuning Modes Three modes of autotuning may be selected They are P only Pl and PID Using P only autotuning gives the maximum value for P that will not cause oscillation The process temperature stabilizes at some point near the setpoint Using Pl or PID control results in stable control at the setpoint The Derivative or D term in PID is used to make the controller more responsive to changes in setpoint or thermal load It does not affect the control accuracy when the system has stabilized However derivative action by it s nature amplifies noise Therefore PID autotuning and control should only be used with very quiet systems Pl control should be used with all others Sensor type has a significant impact on measurement noise The Model 24C uses a ratiometric technique to measure resistor sensors such as Thermistors Platinum RT
77. Menu Operation Instrument Setup Menus To access the various instrument setup menus press one of the Setup Menu keys The display must be in Home Status in order for these keys to be active The user may exit a Setup Menu and return to the Home Status display at any time by pressing the Home key Menus contain several lines so scroll through the display using the Navigation keys The last character of each line in a setup menu is the format indicator The indicator will be blank until the cursor is moved to the line Format indicators are Numeric entry Enumeration entry using the and 0 keys 8 The line is selected by pressing the Select key The Setpoint Menu The setpoint menu is accessed by pressing the Set Pt key This gives one key access to the setpoints for all of the control loops Press the Home key to exit the menu without update The Alarm Status Display Menu The current status of the temperature alarms may be viewed by pressing the Alarm key Alarms are set for each input channel using the Input Channel Setup menu described below When an alarm is asserted the Alarm LED on the front panel will light Pressing the Alarm key will display all of the alarms Status is shown as follows No alarm LO Low temperature alarm HI High temperature alarm The letter L at the end of the line indicates that the alarm is latched A latched alarm is asserted when the alarm condition is set It stays assert
78. NGe REG Tore RATe In the above INPut and LOOP are root keywords whereas UNITs and RATe are second level keywords A colon separates a command keyword from lower level keyword Command Format The format used to show commands is shown here INPut A B ALARm HIGH lt value gt NAMe name The command language is case insensitive but commands are shown here as a mixture of upper and lower case letters The upper case letters indicate the abbreviated spelling for the command For shorter program lines send the abbreviated form For better program readability send the long form For example in the above statement INP and INPUT are all acceptable Braces enclose the parameter choices for a given command string The braces are not sent as part of the command string A vertical bar separates multiple parameter choices for a given command string Triangle brackets lt gt indicate that you must specify a numeric value for the enclosed parameter Double quote marks must enclose string parameters Commands are terminated using a semicolon character The semicolon at the end of the line is assumed and is optional The lt gt and characters are for the illustration of the command syntax and not part of the command syntax 106 Cryo con Model 24C Remote Programming Guide Command Separators A colon is used to separate a command keyword from a lower level keyword It is nece
79. Parameter is numeric and is in percent of full scale output power Acommon value is 5 for 5 LOOP 1 2 3 4 AUTotune TIMeout lt num gt Set or query the autotune timeout Parameter is numeric and is in units of Seconds LOOP 1 2 3 4 AUTotune PGAin Query the autotune generated proportional or P gain parameter This query will return a value of 1 until the autotune status is Complete LOOP 1 2 3 4 AUTotune PGAin Query the autotune generated integrator or Loan parameter This query will return a value of 1 until the autotune status is Complete LOOP 1 2 3 4 AUTotune DGAin Query the autotune generated derivative or D gain parameter This query will return a value of 1 until the autotune status is Complete 129 Cryo con Model 24C Remote Programming Guide LOOP 1 2 3 4 AUTotune STATus Queries the status of the autotune process Return values are IDLE Autotune has not started RUNNING Autotune is running COMPLETE Autotune successfully completed FAILED Unable to generate PID values ABORT Aborted by operator intervention OVERTEMP commands These commands are associated with the heater s Over Temperature Disconnect OTD feature This is used to disconnect the heater if a specified temperature is exceeded on any selected input channel OVERtemp ENABle ON OFF Sets and queries the Over Temperature Disconnect enable The OTD does not function if disabled OVERtemp SOURce A B C D Sets and queries
80. The logical AND of the ESR and ESE registers sets the Standard Event register in the Status Byte STB 113 Cryo con Model 24C Remote Programming Guide The Status Byte The Status Byte STB is defined by the SCPI and is used to collect individual status bits from the ESE and the ISR as well as to identify that the instrument has a message for the host in it s output queue It is queried using the Common Command STB Bits are defined as follows STB Bw ens eis eka ee ewe emi ew Where Bit6 RQS Request for Service Bit5 SE Standard Event This bit is set as the logical AND of the ESR and ESE registers Bit4 MAV Message Available Bit3 IE Instrument Event This bit is set as the logical AND of the ISR and ISE registers The Status Byte Register The Status Enable Register SRE is defined by the mask register for the STB It is set and queried using the Common Commands SRE The logical AND of the SRE and STB registers is used to generate a service request on the GPIB interface 114 Cryo con Model 24C Remote Programming Guide Remote Command Tree STOP CONTrol CONTrol SYSTem LOCKout ON OFF SYSTem NVSave SYSTem REMLed ON OFF SYSTem BEEP lt seconds gt SYSTem DISTc 0 5 1 2 4 8 16 32 64 SYSTem ADRes lt address gt SYSTem RESeed SYSTem HOMe SYSTem SYNCtaps lt taps gt SYSTem NAMe name SYSTem HWRev SYSTem FWREV SYSTem
81. UNt Queries the number of entries in the log buffer DLOG DLOG READ Reads the entire contents of the log buffer Each record is sent on a single line Format is lt gt MM DD YYYY HR MN SC ChA ChB ChC ChD where lt gt is the record number MM DD YYYY is the date in Month Day Year format HR MN SC is the time in Hour Minute Second format Lines end with a lt CR gt lt LF gt sequence End of transmission is indicated by a line that only contains a semi colon DLOG RESEt Sets the logging record number to zero DLOG CLEAr Clears the data logging buffer 137 Cryo con Model 24C Remote Programming Guide Code snippet in C The following code opens a Cryo con instrument at address 192 168 1 5 on the Local Area Network It is written in Microsoft Visual C and uses the eZNET LAN library provided on the Cryo con utility CD Il Example Ethernet LAN program using C TCPIP declarations include TCPIPdrv h TCPIPdrv LAN Define global LAN object char IPA 192 168 1 5 Instrument s IP address on the LAN char tempstr 257 temporary character string Open the instrument If LAN open IPA can t connect LAN close throw Can t talk to instrument y read the IDN string LAN IO IDN tempstr 256 printf IDN is sin tempstr Print IDN read the MAC address LAN IO net mac tempstr 256 printf MAC is s n tempstr Start temperature control
82. User s Guide Model 24C Cryogenic Temperature Controller CRYOGENIC CONTROL SYSTEMS INC P O Box 7012 Rancho Santa Fe CA 92067 Tel 858 756 3900 Fax 858 759 3515 www cryocon com Copyright 2010 2014 Cryogenic Control Systems Inc All Rights Reserved Printing History Edition 3f Certification Cryogenic Control Systems Inc Cryo con certifies that this product met its published specifications at the time of shipment Cryo con further certifies that its calibration measurements are traceable to the United States National Institute of Standards and Technology NIST Warranty This product is warranted against defects in materials and workmanship for a period of one year from date of shipment During this period Cryo con will at its option either repair or replace products which prove to be defective For products returned to Cryo con for warranty service the Buyer shall prepay shipping charges and Cryo con shall pay shipping charges to return the product to the Buyer However the Buyer shall pay all shipping charges duties and taxes for products returned to Cryo con from another country Warranty Service For warranty service or repair this product must be returned to a service facility designated by Cryo con Limitation of Warranty The foregoing warranty shall not apply to defects resulting from improper or inadequate maintenance by the Buyer Buyer supplied products or interfacing unauthorized
83. Volt input voltage range 30 Cryo con Model 24C Specifications Features and Functions Gallium Arsenide Diode Sensors Gallium Arsenide diodes or 6 Volt diodes are sometimes used in systems where magnetic fields are present Use is limited to operation above about 30K with fields of less than 5T The Model 24C supports these sensors down to 25K If your requirements are for lower temperature operation Ruthenium Oxide is a better choice Gallium Arsenide sensors do not fit standard calibration curves therefore the user must provide a sensor specific curve before using this type of sensor Cryogenic Linear Temperature Sensor CLTS Supported by use of a 100uA constant current AC resistance bridge A standard calibration curve for the Vishay CLTS 2B sensor is available on the utility CD Maximum resistance is 1 2KQ and minimum is 100 Sensor type is PTC1K PTC Resistor Sensor RTDs The Model 24C supports all types of Positive Temperature Coefficient PTC resistive sensors using a constant current AC or DC resistance bridge technique Standard calibration curves are provided for DIN43760 and IEC751 Platinum sensors These curves have been extended down to 14K Below that the sensors can be used with user supplied calibration curves A table of recommended setups for various types of PTC resistor sensors is shown here Table 11 PTC Resistor Sensor Configuration When AC excitation is On the sensor excitation curre
84. WG cryogenic ribbon cable a Wires may be separated by dipping in Isopropyl Alcohol and Cable Color Codes ee Sees then wiping clean Insulation is Formvar and is difficult to strip Techniques include use of a mechanical stripper scrapping with a razor blade and passing the wire quickly over a low flame EES 164 Cryo con Model 24C Appendix E Sensor Data The BB package is easily mounted with a 4 40 brass screw A brass screw is recommended because thermal stress will be reduced at cryogenic temperature The mounting surface should be clean A rinse with Isopropyl Alcohol is recommended First apply a small amount of Apiezonf N grease to the threads of the screw and on the mounting surface of the sensor package Next place the bobbin on the mounting surface insert screw through bobbin and lightly tighten The Canister Sensor Package Cryo con s Ruthenium Oxide sensors are available in a small 0 95 x 0 2 cylindrical canister package Construction Gold plated cylindrical OHFC copper canister Stycast epoxy filler There is no internal atmosphere Epoxy limits the maximum storage temperature to 400K Leads Four 36 AWG Phosphor Bronze color coded Formvar insulation Mass 0 4g Installation Use a 0 101 diameter drill Place a small amount of Apiezon N grease in the hole before inserting the sensor Ensure that the leads are thermally anchored Cable Color Code 0 200in 5 08mm Cem J
85. _Samp1e Holder the current setpoint and the heater status 2 5 1 44 5 K 300 000K Htr Off If the control loop is OFF and there are no error conditions the heater status field simply shows OFF Htr Off If the control loop is actively engaged a brief status is displayed showing the current output power and range For a detailed description of control loop 24 HI status press the Loop 1 or Loop 2 keys to go to the heater configuration menu Here complete status is displayed in real time If the control loop was disengaged by a detected error condition the heater status field shows an indicator of the error as follows Control Loop Error Status Htr Off Normal display for a control loop that is OFF Active loop controlling temperature Percent output power and range are indicated in real time Indicates that the controller s internal temperature monitor circuit shut off the heater because the internal heat sink temperature is too high After the controller has been allowed to cool to an acceptable temperature pressing the CONTROL button will clear the error and re start control Note The current temperature of the internal heat sinks for Loop 1 and Loop 2 are displayed in the heater configuration menu Overtemp An independent read back of the heater output current differs significantly Readback from the current that the controller is attempting to set This is usually caused by an open heater or
86. always in units of Kelvin ChA Radiation Shield Thermocouple Sensor Configuration 78 12K FS Input 70mV Return to ChA cfg 96 Cryo con Model 24C Basic Setup and Operation Thermocouple Device Installation The thermocouple device must first be connected to a standard thermocouple mini spade connector of the proper type Wires are attached using the screw terminals Polarity is marked on the input connector and a summary of common thermocouple types is given in the table below The input connector should have its plastic back shell and rubber grommet installed in order to prevent local air currents from generating errors in the cold junction circuitry Connector S R Purple Chrome Constantan H Purple Red Yellow Chrome Aluminum Yellow Red T Copper Constantan Blue Red Chromel Chromel Gold Table 36 Thermocouple Polarities Note that the Chromel AuFe device is a special cryogenic device The connector used is White indicating a type U unspecified device Grounded vs Floating Thermocouples Electrically floating devices are always recommended because they provide generally lower noise operation and cannot facilitate ground loop conditions However the thermocouple module inputs are differential and have a high impedance to ground This will allow operation with grounded devices in most systems Always ensure that there is no more than a 5V difference between the grounded thermocouple and the instrument s chassi
87. amming Guide LOOP 1 2 3 4 HTRRead Queries the actual output power of either control loop The output current of the heaters is continuously monitored by an independent read back circuit The read back power reported by this command is a percent of full scale The absolute value of full scale is determined by the selected heater range Note that the read back value is a percent of full scale power To compute the output current first compute the square root of the read back value LOOP 1 LOAD 50 25 Sets or queries the load resistance setting of the primary heater Loop 1 Selections are 50 for a 500 load and a 50W maximum output power 25 for a 250 load and a 25W maximum output power Note Loop 2 always requires a 500 load so this command is ignored LOOP 1 2 3 4 MAXPwr lt maxpwr gt Sets or queries the maximum output power setting of the selected control loop lt MaxPwr gt is the desired maximum output power limit expressed as a percentage of full scale LOOP 1 2 3 4 MAXSet lt maxset gt Sets or queries the maximum allowed set point for the selected control loop lt MaxSet gt is the desired maximum set point Setpoint values are in units of the controlling input channel LOOP 1 2 3 4 VSENse Queries the control loop output voltage If the instrument is not controlling temperature return is 0 00V LOOP 1 2 3 4 ISENse Queries the control loop output current If the instrument is not controlling temperatu
88. and then press the Enter key E High temperature alarm enable Selections are Low Alarm 200 000 Setpoint for the Low Temperature alarm Low Enable Yes Enables latching alarms on the selected input channel 10 Deadband 0 250 Alarm dead band S Enables the internal audio alarm to sound on any Audible Ena Yes enabled alarm condition Enables or disables latching alarm conditions A Latch Enable Yes latched alarm is cleared by pressing the Alarm key followed by Home key Table 18 Input Channel Configuration Menu 52 Cryo con Model 24C Front Panel Menu Operation Temperature Units Enumeration Default K The Temperature Units field line 1 assigns the units used to display temperature for the input channel Options are K for Kelvin C for Celsius F for Fahrenheit and S for sensor units Note that if the S option is selected the actual sensor units will be displayed when the field is deselected Available sensor units are V for Volts and Q for Ohms Use the or 0 key to scroll through all of the options When the desired units are displayed press the Enter key to make the selection The display will now show the current temperature with the new units Sensor Type Selection Enumeration Line 2 selects the Sensor type for the input channel When this field is selected the scroll keys are used to scroll through all of the available sensor types Factory installed sensors appear first and then user sensors
89. annels Up to four modules can be connected to a single instrument For all sensor types conversion of a sensor reading into temperature is performed by using a Cubic Spline interpolation algorithm In addition to providing higher accuracy than conventional linear interpolation the spline function eliminates discontinuities during temperature ramps or sweeps by ensuring that the first and second derivatives are continuous Control Loops There are four independent control loop outputs 1 Loop 1 heater output is a linear low noise RFI filtered current source that can provide up to 1 0 Ampere into 50Q resistive loads Three full scale ranges are available in decade increments down to 500mW full scale 2 Loop 2 is a linear heater with two output ranges of 25 Watts and 2 5 Watt full scale into a 50Q load 3 Loop 3 and 4 are a non powered analog voltage output intended to control an external booster power supply Output is selectable at 10 or 5 Volts full scale User Interface The Model 24C s user interface consists of a large bright TFT type Liquid Crystal Display and a full 21 key keypad In this user friendly interface all features and functions of the instrument can be accessed via this simple and intuitive menu driven interface The Home screen projects four user configurable zones that allow the real time display of all input channel control loop and instrument status information From this screen accessing any of the inst
90. arge volume of data is returned Cryocon Utility Software Click on the Upload Internal Datalog button This will enable reading the log buffer to a spreadsheet csv file Note Reading a full log buffer takes about six minutes on any of the remote interfaces 63 Cryo con Model 24C Front Panel Menu Operation Network Configuration Menu Navigate to this menu by pressing the System key and selecting the Network Config field Network Configuration Menu a Instrument name reported over the LAN May be Dev M24C1234 modified by using the embedded web page 2 Network IP address Numeric entry Factory default 2 IP 192 168 1 5 is 192 168 1 5 3 Network subnet mask Numeric entry Default is 255 255 255 0 Network gateway Only used if the instrument is to 4 Gwy 192 168 0 1 be connected through a gateway to the Internet Default is 192 168 0 1 TCP IP port assignment Default is 5000 The UDP Port 5000 port assignment is always the TCP IP port plus 1 Default 5001 J S S P Media Access Control MAC address Unique for o 00 50 C2 6F 40 3F each instrament EN DHCP Ena OFF Enable DHCP IP address assignment A Remote l O Last response Table 23 Network Configuration Menu Local Area Network Setup Setup of the Local Area Network requires a device name an IP address a subnet mask and a gateway The device name is any 15 character string It is reported on the display but can only be changed via a remo
91. avigate to the OTD Configuration menu by pressing the System key and then selecting the Over Temp Config field The Over Temperature Disconnect OTD feature monitors a selected input channel for an over temperature condition If this exists all heaters outputs are disconnected and the Loop Status indicator is set to OTDisconn A mechanical relay is used for the disconnect so that the load is protected even if the condition was caused by a fault in the controller s output circuitry The OTD must first be configured to monitor one of the input channels Note that the OTD feature is completely independent of control loop function and may monitor any input Next an OTD Setpoint must be specified This is the temperature at which an over temperature shut down is asserted Temperature units are taken from the source input channel Finally the OTD function must be enabled Important The Over Temperature Disconnect is an important cryostat protection feature The user is encouraged to apply it Over Temperature Disconnect Configuration 3 Sets the Over Temperature Disconnect enable OTD Enable Off Selections are On or Off S Sets the Over Temperature Disconnect source OTD Source ChA input channel Selections are ChA or ChB i Sets the Over Temperature Disconnect setpoint Table 22 Over Temperature Disconnect Configuration 62 Cryo con Model 24C Front Panel Menu Operation Data Logging Configuration Menu No
92. both off To enable or disable an individual loop go to the Loop Configuration Menu menu and select the desired Type The Home key is used to take the display to one of the Home Status displays These displays show the full status of the instrument The Enter key is used to enter numeric data or selections The Keypad and Setup Menu Keys The keypad keys on the far right side of the instrument serve a cha op cho cho dual function When the display is showing one of the a G ES configuration menus the keypad is used for navigation and data esc options Loop1 Loop2 entry When the display is in the Home Status Display their SA Cs B Cc function is identified by a label printed just above the key and is os can E Auto as follows ChA ChB ChC ChD Go to the Input Channel Setup menu Loop 1 Loop 2 Go to the Control Loop Setup menu Auto Tune Go to the auto tuning menu for either loop Config Go to the User Configurations menu Sensors Go to the Sensors configuration menu including sensor calibration curves PID Table Go to the PID tables setup menu System Go to the System setup menu This includes fields for Remote Input Output Display filters and the Over Temperature Disconnect feature Display Go to the Display setup menu This allows configuration of the front panel display from a list of options Alarm Go to the Alarm Status menu Set Pt Set the setpoint values for both control loops
93. c Control Systems Inc reset click Connect again Boot Loader Waiting for connect IP 192 168 1 5 Port 5000 Rev 1 07A to re establish contact This activates the Program Verify button The instrument will now display Connected Click the Program Verify button to start the firmware download The last few lines of the instrument s display will indicate the status First the flash memories are erased and then individual records are programmed and verified There are about 6800 records in a typical file and the programming process takes about ten minutes When programming is complete the unit will automatically reset and begin running the updated firmware Factory defaults are also restored 149 Cryo con Model 24C Appendix B Updating Instrument Firmware It is possible to power the instrument OFF during the programming process This will require a re start of the entire process after powering ON again Once the download progress starts the instrument powers up in the boot loader mode and will not run the normal instrument firmware until the entire download process is completed without error If an error occurs an error message will display on the instrument s front panel for 20 seconds and then an alert box will show on the PC Types of errors are 1 Failure to erase flash memory 2 Write error and 3 Verify error If the error persists after several programming attempts there is a hardware problem and you will n
94. cess to the Model 24C s fuses and voltage selector switch is made by using a screwdriver to open fuse drawer in the power entry module A slot is provided above the voltage selector window for this purpose The fuse and voltage selection drawer cannot be opened while the AC power cord is connected Voltage selection is performed by rotating the selector cams until the desired voltage shows through the window shown There are two fuses that may be removed by pulling out the fuse modules below the voltage selector Fuses are specified according to the AC power line voltage used 100VAC 120VAC 2 0A slow blow Littlefuse 313 002 220VAC 240VAC 1 0A slow blow Littlefuse 313 001 Table 14 AC Power Line Fuses Mechanical Form Factors and Environmental Enclosure The Model 24C enclosure is standard 2 U half width 17 inch rack mountable type that may be used either stand alone or incorporated in an instrument rack Dimensions are 8 5 W x 3 5 H x 12 D Weight is 9 Lbs An instrument bail and feet are standard Rack Mount kits are available from Cryo con for both single instrument or side by side dual configurations A rack mount kit is optional 38 Cryo con Model 24C Specifications Features and Functions Environmental and Safety Concerns Safety The Model 24C protects the operator and surrounding area from electric shock or burn mechanical hazards excessive temperature and spread of fire from the instrument Keep Away F
95. cifications Features and Functions Specification Summary User Interface Display Type 40 character by 8 line TFT LCD with LED backlight Number of Inputs Displayed Four Keypad Sealed Silicon Rubber Temperature Display Six significant digits autoranged Display Update Rate 0 5 Seconds Display Units K C F or native sensor units Display Resolution User selectable to seven significant digits Input Channels There are four input channels each of which may be independently configured for any of the supported sensor types Sensor Connection 4 wire differential Screw in type DIN 6 circular Connections are described in the Sensor Connections section Supported Sensors Include Temperature SA Silicon diode 10uA DC 1 4 to 475K Platinum RTD Constant Current ImAAC 14 to 1200K Constant Voltage AC 100mK to 420K Lakeshore all types Ruthenium Oxide Constant Voltage AC 100mK to 273K Sl RO 600 SI RO 105 o Constenecu Current ImAAC 1 4to 800K Oxford PHZ 0002 ermano Constant Voltage AC 100mK to 100K lAdSem Inc Thermistor Co Aaa Table 5 Supported Sensor Types 21 Cryo con Model 24C Specifications Features and Functions Sensor Selection Front Panel or remote interface There are no internal jumpers or switches Sample Rate 15Hz per channel in all measurement modes Digital Resolution 24 bits Measurement Filter 0 5 1 2 4 8 16 32 and 64 Seconds Calibration Curves Built in curves for ind
96. cimal integer ranging from zero to 200 132 Cryo con Model 24C Remote Programming Guide SENSorix lt index gt UNITs VOLT LOGOHM OHMS Sets or queries the units of a user installed calibration curve at lt index gt For information on the curve units refer to the User Calibration Curve File Format section SENSorix lt index gt TYPe DIODE ACR PTC100 PTC1K TC70 NTC10UA Sets or queries the type of sensor at lt index gt For more information on sensor types please refer to the Input Configurations section Index is O through 7 SENSorix lt index gt MULTiply lt multiplier gt Sets or queries the multiplier field of a user installed calibration curve at lt index gt For information on the multiplier refer to the User Calibration Curve File Format section 133 Cryo con Model 24C Remote Programming Guide PIDTABLE commands The PIDTABLE commands are used to transfer PID tables between the Model 24C and the host controller Use of the Cryo con Utility software to transfer PID tables is recommended since the process is relatively complex PID Tables are referenced by their index number which is between 1 and 6 Table data corresponding to a specific index may be identified using the PIDTABLE query There is a maximum of 16 entries in each PID table Each entry contains a setpoint P and D coefficients and a heater range The file format of a PID table is shown below lt name gt n lt entry 0
97. cluding the double quote String parameters must be enclosed in double quotes For example CONFig 4 NAMe Cold Plate 108 Cryo con Model 24C Remote Programming Guide Commonly Used Commande A complete summary of remote commands is given in the User s Manual chapter titled Remote Command Summary The manual also has complete descriptions of all remote commands This section is intended to show a few of the more commonly used commands O NOTE Remote commands are not case sensitive Function Command Comment Instrument Identification Read the instrument identification string idn Returns the instrument identification string in IEEE 488 2 format For example Cryo con 24C 204683 1 01A identifies the manufacturer followed by the model name serial number and firmware revision code Input Channel Commands Parameter for the input is A B C or D corresponding to inputs A B C or D Read the temperature on input channel B input b Temperature is returned in the current display units Format is a numeric string For example 123 4567 Set the temperature units on input channel A to Kelvin input a units k Choices are K Kelvin C Celsius F Fahrenheit and S native sensor units Volts or Ohms Read the temperature units on channel B input b units Return is K C F or S Control Loop Start Stop commands or off
98. cs OFFSET is the offset of the best fit straight line passing through all temperature samples that have been collected since the statitics were reset OFFSET is in units of the input channel display INPut A B C D STAts TIMe Queries the time duration over which input channel statistics have been accumulated Query only INPut A B C D STAts RESet Resets the accumulation of input channel statistical data Command only affects the selected input channel INPut A B C D TCOFfset lt offset gt Sets or queries the offset value for thermocouple inputs lt offset gt is the decimal value of offset and is in units of Kelvin Refer to the section on Using Thermocouple Sensors for more information 125 Cryo con Model 24C Remote Programming Guide LOOP commands Loop commands are used to configure and monitor the controller s temperature control loops Loop 1 is the controller s primary heater output channel The Model 24C has three ranges Loop 2 is a secondary output The Model 24C has a single range linear heater LOOP 1 2 3 4 SOURce A B C D Sets and queries the selected control loop s controlling input channel which may be any one of the four input channels LOOP 1 2 3 4 SETPt lt setpt gt Sets and queries the selected control loop s setpoint This is a numeric value that has units determined by the display units of the controlling input channel Values above the one set in the maximum setpoint or below zero are rejected
99. cted Using a 25Q load the heater will be automatically configured to have a compliance voltage of 25V With a 50Q load the compliance voltage is 50V In either case the maximum output current is 1 0A Range VE Fusco pak pepee O mmn v sv o 25waw owas C meam 25v sv ossa 25wa sowans Table 12 Loop 1 Heater output ranges Take care to ensure that the proper load resistance is selected Connection to a 250 load while a 50Q is selected will result in overheating and eventual automatic heater shutdown Conversely connection to a 50Q load while setting a 25Q load will result in the dissipation of only one half of the indicated heater power in the load Load resistance and Full Scale Output Range are selected via the front panel or any of the remote interfaces Heater output power displays are based on the heater read back circuitry which measures output current independently of the actual heater circuitry Thus heater fault conditions are detected and their corresponding alarms asserted Note Heater output displays are given as a percentage of output power not output current In order to compute actual output power multiply this percentage by the full scale power of the selected range However to compute actual output current you must first take the square root of the percentage and then multiply by the full scale current 34 Cryo con Model 24C Specifications Features and Functions
100. ctor is as follows N C NC NC Table 43 RS 232 DB 9 Connector Pinout The cable used to connect the Model 24C to a computer serial port is a Dual Female Null Modem cable An example is Digikey Inc part number AE1033 ND ee EE Model 34 PC DCH Ill 1 pcp a 3 IS TX 3 3 TX DTR 4 4 DTR GND ee 5 GND DSR 6 6 DSR a a cts 8 8 CTs RI 9 oe RI DB9 DB9 DB9 DB9 Male Female Female Male Figure 9 RS 232 Null Modem Cable 184 Cryo con Model 24C Index Index AC DOWET da td A Manual mode 35 COMNECHON muta dis 37 Manual puming nono 157 Old dee EE EE 14 39 Maximum output eee 57 127 128 Freouencn 61 88 Maximum setpoint seeeeeeeeeeeeeeeeseerrrr nenene 57 Fuse replacement A 38 Off 19 Low voltage 156 OT Diiis 62 Protective Ground 37 Output power limit 57 Reouirements A 26 PQ in eeeee 55 E AAA iiienn tinie i 41 PID 19 Voltage Gelection 38 PID configuration 55 EE PID control mode 35 ET DEE 51 PID Table ivan taa 35 57 126 L ele 53 54 Eaa AT T A PEE AEAEE SEES triada 55 56 elle Ee GE 52 Proportional oan 55 127 Latched tucan dis a c 53 54 e el Le cad id 58 85 ele 52 A a E 86 SO AE 53 54 Operativo ia 85 A Suaa araa e aea aeea EAE EEE ad 42 GE 86 VIEWING BE 51 Ramp aia 19 Auto Control Mode 62 Ramp Pitan Mev Sader aah suas 19 AUTOTUNINO BEE SE Le EE 56 65 Moes cisco cda 81 Readback AA ei ed 34 PretUNING
101. ds to this enclosure on one end and to the cryostat on the other completes a continuous shield thus forming a Faraday Cage RFI shield around the entire system In order for the instrument s grounding and shielding scheme is working effectively 1 All sensors and heaters must be electrically floating with respect to ground 2 The instrument side of all sensor cable shields must be connected to their connector s metal back shell Heater cables should have their shields connected to the chassis ground lug 3 Atleast one cable must have it s shield connected to the connector s back shell on the cryostat end 4 Agood quality earth ground point must be established All instruments and the cryostat should have a direct connection to this point Note There is some possibility that a ground loop will be formed when a sensor cable shield is connected at both the cryostat and instrument end If this happens it is recommended that the ground loop first be fixed and then the connection be made Ground loops are usually fixed by properly implementing a single point ground scheme Note The Ethernet LAN interface is electrically isolated and cannot introduce ground loops 99 Cryo con Model 24C Instrument Calibration Instrument Calibration Calibration of the Model 24C controller requires the use of various voltage and resistance standards in order to generate calibration factors for the many measurement range
102. e Input Commands The INPUT group of commands are associated with the configuration and status of the four input channels Parameter references to the input channels may be e Numeric ranging in value from zero to two e Channel ID tags including CHA or CHB e Alphabetic including A or B INPut A B C D or INPut A B C D TEMPerature The INPUT query reports the current temperature reading on any of the input channels Temperature is filtered by the display time constant filter and reported in display units Query only INPut A B C D UNITS K C F Si Sets or queries the display units of temperature used by the specified input channel Units may be K for Kelvin C for Celsius F for Fahrenheit or S for primitive sensor units In the case of sensor units the instrument will determine if the actual units are Volts or Ohms based on the actual sensor type INPut A B C D NAMe Name String Sets or queries the name string for the selected input channel The name string can be up to 15 ASCII characters The string is used to name the input channel in order to clarify it s use INPut A B C D SENPr The INPUT SENPR query reports the reading on a selected input channel For diode sensors the reading is in Volts while resistor sensors are reported in Ohms The reading is not filtered by the display time constant filter However the synchronous input filter has been applied Query only INPut A B C D VBlas 10MV 3 0MV 1 0MV 3
103. e Cryo con Utility Software Any remote command or query that is recognized by the instrument can be used in a script file This includes commands that read and write user sensor calibration curves and PID tables A complete description of available remote commands is given in the chapter titled Remote Programming Guide The Remote Command Tree section is particularly useful for the advanced user Script File Structure Header and Footer Like all XML files script files have the following header and footer lt xml version 1 0 gt lt Transactions gt lt Transactions gt All user supplied information is placed between the Transactions tags 167 Cryo con Model 24C Appendix F Configuration Scripts Basic XML Tags Comment lt gt Inserts a comment in the file for documentation and readability The comment within the angle brackets after the exclamation is ignored by the software lt Download User Curve 4 gt Model lt Model gt lt Model gt Contains the Crycon instrument model number for source destination verification lt Model gt Model24 Version 2 03 lt Model gt Remote Command lt Command gt lt Command gt Send a remote command to the instrument Commands can be any of the instrument s commands as described in the Remote Programming Guide lt Command gt input c sensor 2 lt Command gt lt Command gt LOOP 1 SOURCE A Setpt 20 0 lt Command gt lt Command gt OVERTEMP ENABLE ON lt Command gt
104. e Minimum and Maximum temperature lines show the temperatures from during the accumulation time Values are shown in the currently selected display units S2 is the temperature variance which is computed as standard deviation squared The M and b fields display the slope and the offset of the LMS best fit straight line to the temperature history data 53 Cryo con Model 24C Front Panel Menu Operation CalGen Sub menu Selection of the CalGen field initiates the calibration curve generator feature This feature is described in the section Using CalGen Setting a Temperature Alarm The Alarm lines are used to setup alarm conditions The Model 24C allows alarm conditions to be assigned independently to any of the input channels High temperature and low temperature alarms may be entered and enabled Note that there is a 0 25K hysteresis in the assertion of high and low temperature alarms Alarm conditions are indicated on the front panel by the Alarm LED and various display fields They are also reported via the remote interfaces When the audible alarm is enabled a high pitched buzzer will sound when an alarm condition is asserted The Model 24C supports latched alarms These are alarms that remain asserted even after the condition that caused the alarm has been cleared To clear a latched alarm first press Alarm to view the Alarm Status Display and then press the Home key to clear Loop Configuration Menu These menus contain all o
105. e rear panel using the 10 pin detachable terminal block provided Fin Funan id CT Relay 2 Common e Loop 3 output Low LS Loop 8 output High 10 Loop 4 output Low Table 42 Loop 2 and Digital Output Connections 183 Cryo con Model 24C Appendix H Rear Panel Connections Ethernet LAN Connection The Ethernet connection on the Model 24C uses a standard RJ 45 connector with two LEDs that are used to indicate status When connecting the Model 24C to a hub or switch a standard Category 5 patch cable is used When connecting the Model 24C directly to the computer a crossover cable should be used The RJ 45 LAN connector has two LEDs The left most LED indicates that a valid connection has been made to a hub or computer ian If the LAN is plugged in and the Connected LED is not on there is a problem that must be addressed before you can communicate with the instrument a The right most LED indicates activity on the LAN It should flicker periodically during normal operation IEEE 488 2 Connections The optional IEEE 488 2 GPIB connection is installed by connecting the dongle to the Ethernet port using the crossover LAN cable provided The interface will be configured by the instrument and will appear to your system as a standard IEEE 488 2 device Connected Activity RS 232 Connections The Model 24C uses a Female DB 9 connector for RS 232 serial communications The pin out of this conne
106. e reversed from other formats Must be manually converted to a crv file before use Software will attempt to parse any text file If the file contains columns of sensor readings vs temperature the entries will be properly parsed and the curve can be used or converted to a crv file after the header dialog box is filled out In order to download a file run the utility software and select Sensor Curve Download The user will be prompted to select a file Once the software has read the file the header information dialog box will appear x Sensor Name R400 RuOx 12345 Sensor Type ACR X Multiplier 1 Unit LogOhms D Number of Pts 104 77 Cryo con Model 24C Basic Setup and Operation The Sensor Name can be any string up to 15 characters that helps identify the sensor The Sensor Type Multiplier and Unit fields affect how the instrument is configured so they must be correctly set or unexpected results will be obtained See mye L t Units Example ams ons n Oo om SP Germanium acr 21 epes Loge Steeg Pre 10 oms Primo Table 30 Recommended Sensor Configuration Data Note that NTC resistor data is generally in units of LogOhms However it can also be in units of Ohms Be sure to check the curve data for reasonableness Note One simple way to generate a sensor calibration curve is to open a similar sensor file with a text editor and paste in your own data The example fil
107. e used by the selected control loop when performing a temperature ramp lt rage gt is the ramp rate in Units Minute This may be a value between 0 and 100 Rate is in display units per Minute LOOP 1 2 3 4 PGAin lt gain gt Sets or queries the selected control loop s proportional gain term This is the P term in PID and is a unit less numeric field with values between 0 off and 1000 LOOP 1 2 3 4 IGAin lt gain gt Sets and queries the integrator gain term used by the selected control loop This is a numeric field with units of seconds Allowed values are 0 off through 1000 seconds LOOP 1 2 3 4 DGAin lt gain gt Sets and queries the differentiator gain term used by the selected control loop This is a numeric field with units of inverse seconds Allowed values are O off through 1000 Seconds Note Use of the D gain term can add significant noise It should never be set to a value greater than 1 4 of the integrator gain LOOP 1 2 3 4 PMANual lt pman gt Sets and queries the output power level used by the selected control loop when it is in the manual control mode lt value gt is the desired selected control loop output power This is a numeric field in units of percent of full scale Actual output power will depend on the loop range setting LOOP 1 2 3 4 OUTPwr Queries the output power of the selected control loop This is a numeric field that is a percent of full scale 127 Cryo con Model 24C Remote Progr
108. ear 77K When the CalGen menu is re entered for curve generation the point captured at 300K is still valid 91 Cryo con Model 24C Basic Setup and Operation CalGen Initial Setup Generation of a calibration curve using CalGen requires the measurement of various temperature points Therefore an input channel must be configured with the correct sensor before the CalGen process can start To initiate the curve generation select the CalGen field on the Input Channel Setup menu This takes the screen to a sub menu for the specific sensor type O Note Before CalGen can be initiated there must be a valid temperature reading on the selected input channel If this is not the case selecting the CalGen field will cause the display of an error message When the input channel has a valid reading CalGen determines if the sensor is a diode or Platinum sensor The calibration curve of the selected input sensor is used as the input to the curve generation process Using CalGen With Diode Sensors Options for generating diode calibration curves are 1 One point near 300K The portion of a diode Sensor curve above 30K is fit to a user specified point near 300K This is a two point fit where the 30K point is taken from the existing calibration curve The portion of the curve below 30K is unaffected 2 Two points 300K and 77K Here two user specified points are taken to fit the diode curve region above 30K The entire curve
109. ed until it is manually cleared by the user Note To clear a latched alarm first press the Alarm key to view the alarms and then press the Home key to clear the latch and return to the Home display 51 Cryo con Model 24C Front Panel Menu Operation Input Channel Configuration Menu These menus contain all of the user configurable parameters for a selected sensor input channel Use the navigation keys to move around the list ChA Sample Holder When the cursor is AE High A arm 109 00 i 7 19 arm na e No located to the left of the Low Alarm 10 60 ChA indicator channels B Sen 32 RO 600 Low Alarm Enable No i Input Config Deadband 0 25 C and D may be displayed CalGen Latched Enable No by pressing the key To Statistics Audible Enable No sequence in the reverse direction press the 0 key Input Channel Configuration Menu Input channel units Selections are K C F or S Here S selects primitive sensor units When S is selected the actual sensor units of Volts or Ohms will be displayed Sensor type selection Allows selection of any Sen 20 Pt100 385 user or factory installed sensor The 20 shown indicates that the current sensor is number 20 3 Input Config Go to the input configuration menu 8CalGen Go to the CalGen screen Statistics Go to the input channel statistics screen E Setpoint for the High Temperature alarm Use the High Alarm 200 000 keypad for numeric entry
110. eed to contact Cryo con 150 Cryo con Model 24C Appendix C Troubleshooting Guide Appendix C Troubleshooting Guide Error Displays Or an erratic display of temperature Input channel voltage measurement is out of range Ensure that the sensor is connected and properly wired Ensure that the polarity of the sensor connections is correct Refer to the Sensor Connections section Many sensors can be checked with a standard Ohmmeter For resistor sensors ensure that the resistance is correct by measuring across both the Sense and Excitation contacts For a diode sensor measure the forward and reverse resistance to ensure a diode type function Input channel is within range but measurement is outside the limits of the selected sensor s calibration curve Check sensor connections as described above Ensure that the proper sensor has been selected Refer to the Input Channel Configuration Menu section Change the sensor units to Volts or Ohms and ensure that the resulting measurement is within the selected calibration curve Refer to the section on Input Channel Configuration Menu to display the calibration curve 151 Cryo con Model 24C Appendix C Troubleshooting Guide Control Loop and Heater Problems Symptom Condition JU Overtemp displayed The control loops were disengaged by detection of an excessive internal temperature Possible causes Shorted heater Check heater resistance Se
111. el Statistics Input temperature statistics are continuously maintained on each input channel This data may be viewed in real time on the Input Channel menu or accessed via any of the remote I O ports Statistics are Minimum Temperature Maximum Temperature Temperature Variance Slope and Offset of the best fit straight line to temperature history Accumulation Time The temperature history may be cleared using a reset command provided Electrical Isolation and Input Protection The input channel measurement circuitry is electrically isolated from other internal circuits However the common mode voltage between an input sensor connection and the instrument s ground should not exceed 40V Sensor inputs and outputs are provided with protection circuits The differential voltage between sensor inputs should not exceed 15V 33 Cryo con Model 24C Specifications Features and Functions Control Loop Outputs Control Loop 1 Primary Heater Output The Loop 1 heater output is a short circuit protected linear current source This output is heavily regulated and RFI filtered External filters should not be necessary Automatic shutdown circuitry is provided that will protect the heater output stage from excessive temperature Here the heater output will be turned off until the output stage returns to its safe operating area then the output will be returned to normal operation Load resistance values of either 25Q or 50Q may be sele
112. ensor reading in Volts at the desired temperature SenSen is the sensor sensitivity in Volts Kelvin at the desired temperature For example to calculate the measurement accuracy of the Model 22C using a Cryo con S900 sensor at 10K look up the sensor reading and sensitivity in the S900 data table in Appendix G At 10K SenRdg is 1 36317 Volts and SenSen is 0 002604 Volts Kelvin Therefore MAV 60 107 5 107 1 36317 and _ MAV 0 002604 The result is MAV 128uV and MAT 49mK 27 Cryo con Model 24C Specifications Features and Functions PTC Resistor Sensors RTDs The formulas for PTC resistor sensor in the PTC100 range are MAR 0 002 1 0 10 SenVal Where MAT SenSen MAR is the electronic Measurement Accuracy in Ohms MAT is the Measurement Accuracy in Kelvin SenVal is the sensor reading in Ohms at the desired temperature SenSen is the sensor sensitivity in Ohms Kelvin at the desired temperature To calculate the measurement accuracy of the Model 22C using a 100Q Platinum RTD in the PTC100 range with the sensor at 77 35K look up the sensor reading and sensitivity in Appendix G The appendix shows that SenRdg is 20 38Q and SenSen is 0 423 Q Kelvin Therefore the computed values show that MAR 0 004038Q and MAT 9 5mK For ranges other than PTC100 please refer to the PTC Specifications table NTC Resistor Sensors The formulas for NTC resistor sensors are Where MAR SI gt SenVa
113. ention such as pressing the Stop key Temperature Ramping Operation The Model 24C performs a temperature ramp function using a specified ramp rate and target setpoint Once placed in a ramping control mode a ramp is initiated by changing the setpoint The unit then progresses to the new setpoint at the selected ramp rate Upon reaching the new setpoint ramp mode is terminated and standard PID type regulation will be performed Ramping may be independently performed on control loop The procedure for temperature ramping is as follows 1 Set the Ramp Rate in the Heater Configuration Menu This parameter specifies the ramp rate in Units Per Minute where Units are the measurement units of the input channel controlling the heater For example if the input channel units are Kelvin the ramp rate is in K min 2 Select the ramping Control Mode RampP 3 Press CONTROL Now the controller will begin temperature regulation at the current setpoint 4 Enter a new setpoint The controller will enter ramping mode and ramp to the target setpoint at the specified rate 5 When the new setpoint is reached ramping mode terminates and temperature regulation will begin at the new setpoint 6 Entry of a different setpoint will initiate another ramp As a variation on the above procedure 1 The controller may be regulating temperature in any available control mode This mode can be changed to a ramping mode without exiting the control loop Thi
114. er Toggle power Must be held in fortwo seconds stop Disengage dance Control Engage all control loops Home Go to the Home Status Display cha Input Channel Menu for Channel A 7 Scroll Display UP If in data entry mode Escape Additionally if the keypad has been locked by a remote interface pressing this key will unlock it and clear the Remote LED Scroll Display DOWN RES A gt Sensors Goto the sensor setup menu Scroll Display RIGHT P lt owe Jesse E System setup menu Scroll Display RIGHT Display Goo the display configuration men O i Change the setpoint value for either control loop Scroll to NEXT selection Go to the Alarm Status menu Scroll to PREVIOUS selection nput Channel Menu for Channel B ChA Cc Cc Cc a 2 a CS e Loop2 Goto the Loop 2 setup menu 8 Pbre PD table memo C o Auto Tune Autotune mena Table 15 Keypad key functions The LED indicators and Audible Alarm There are three LED indicators located just below the main display The blue Control LED is illuminated whenever either of the control loops are engaged and actively controlling temperature To disengage the loops press the Stop key The red Alarm LED is illuminated whenever a user programmed alarm has been triggered To clear the alarm the enabled event that is asserting the alarm must be disabled Press the Alarm key to view the status of all alarms
115. ercentage of full scale PD Standard PID control R Temperature ramp control Uses PID control to perform a ampP temperature ramp Temperature ramp control using a PID table Uses PID control to RampT perform a temperature ramp Table 4 Control Type Summary Table PID control mode where the PID coefficients are generated from a stored user supplied PID table Caution The Model 24C has an automatic control on power up feature If enabled the controller will automatically begin controlling temperature whenever AC power is applied For a complete description of this function please see the Auto Ctl function in the System Functions menu section Restoring Factory Defaults Factory default settings may be restored with the following simple procedure 1 Turn AC power OFF by pressing the Power key 2 Press and hold the Enter key while turning AC power back ON Keep the key pressed until you see the power up display indicating that defaults have been restored NOTE Factory defaults may be restored at any time by use of the following sequence 1 Turn AC power OFF 2 Press and hold the Enter key while turning power back ON This sequence will restore factory defaults including resetting user supplied sensor calibration curves and saved user configurations However it will NOT erase the instrument s internal calibration data 19 Cryo con Model 24C Specifications Features and Functions Spe
116. ere is still the possibility of instability The Model 24C uses a digital time synchronous filter to actively subtract the cooler s signature resulting in much higher control accuracy and loop responsiveness With the Synchronous Filter enabled the controller synchronously subtracts the thermal signal from the input temperature signal Since synchronous subtraction is used to eliminate the undesired signature there is no phase shift or loss of signal energy as would be the case if a classical notch or low pass filter is used Subtraction is performed ahead of the PID control loop Therefore the input to the loop contains only the baseline temperature signal Using the Input Signature Subtraction filter gives much higher temperature measurement accuracy and allows the use of aggressive high precision control It is applicable to virtually any cryocooler system Synchronous Filter Setup To use the synchronous filter two parameters must be set e The AC Line Frequency setting must correspond to the actual power input AC frequency The filter uses this to synchronize to the cooler e The Synchronous Filter Taps parameter must be set for the specific cryocooler type This parameter gives the filter a starting point for the number of filter taps required to perform an accurate subtraction Determination of a proper setting may require some experimentation To set the AC Line Frequency go to the System menu and scroll down Sync Filt Taps 07
117. erenced by an index number In the Model 24C there are eight user curves numbered 1 through 8 The CALCUR data block consists of many lines of ASCII text The format is the same as the file format for user calibration curves which is detailed in the section User Calibration Curve File Format CALCUR lt index gt Sets or queries sensor calibration curve data Uses a fragmented message protocol to sens many lines of ASCII text to the instrument Note It is much easier to use Cryo con s Utility Software to send and receive sensor calibration curves NOTE The instrument takes about five seconds to process and store a calibration curve Please insert this time delay between transferring sequential curves Sensor commands Sensor commands are used to set and query information about the sensors installed in the controller Both factory and user installed sensors can be queried but only user sensors may be edited NOTE Factory installed sensors are indexed from 0 to 61 User installed sensors have index values from 61 to 68 corresponding to user curves 1 through 8 For additional information refer to Appendix A SENSorix lt index gt name Name String Sets and queries the name string of the user installed sensor at index lt index gt The name string can be up to 15 ASCII characters SENSorix lt index gt NENTry Queries the number of entries in the user installed sensor at index lt index gt Response is a de
118. es The start and top level of this process is the PID Tables menu Two menu screens below this are used to enter numeric data Here is an overview of the process 1 The PID Tables menu is used to select the PID Table number zero through three 2 Once the table is identified selecting the EDIT PID TABLE line will take the menu used to edit individual lines of the selected table 3 To enter or edit an entry set the desired entry index and enter the zone data on the following lines 4 The last line of this menu is used to save the table when the entire table is complete When a table is saved it is automatically conditioned so that it can be used directly by the control loop software The conditioning deletes all entries with setpoint values of zero or less and sorts the table based on setpoint Therefore an entry may be deleted by setting the setpoint to any negative number 65 Cryo con Model 24C Front Panel Menu Operation The PID Table Menu The PID Table Menu is accessed by pressing the PID Table key from the Home Display and then selecting a table Edit PID Table 01 Table Index P D The first line of this display Setpt 300 00K shows which PID table is D ye GE being edited Placing the SaveTable amp Exit cursor on this line will allow the user to scroll through all of the tables CS AT CA ATTE aD id D value in units of inverse Seconds SetPt Setpoint in units of temperature Ch Input channel
119. es are set by the line voltage selector in the Power Entry Module on the rear panel The power cord will be a standard detachable 3 prong type Line voltage selections are 100 120 220 or 240VAC Tolerance on voltages is 10 to 5 for specified accuracy and 10 for reduced full scale heater output in the highest output range The power jack and mating plug of the power cable meet Underwriters Laboratories UL and International Electrotechnical Commission IEC safety standards User replaceable fuses are incorporated in the Power Entry Module O Note The Model 24C uses a smart power on off scheme When the power button on the front panel is pressed to turn the unit off the instrument s setup is copied to flash memory and restored on the next power up If the front panel button is not used to toggle power to the instrument the user should configure it and cycle power from the front panel button one time This will ensure that the proper setup is restored when AC power is applied Caution Protective Ground To minimize shock hazard the instrument is equipped with a three conductor AC power cable Plug the power cable into an approved three contact electrical outlet or use a three contact adapter with the grounding wire green firmly connected to an electrical ground safety ground at the power outlet 37 Cryo con Model 24C Specifications Features and Functions Fuse Replacement and Voltage Selection Ac
120. es in the above table are for that purpose They are located in the Model 24C sub directory of the Cryo con utility software package 78 Cryo con Model 24C Basic Setup and Operation At this point it is a good idea to view a graph of the curve data xj 40 000 3 021 Sensor Curve 27 720 4 217 OuputiLogonm er The above graph is for a Ruthenium Oxide sensor with units of LogOhms It shows the typical highly non linear curve for that type sensor If the curve data was in units of Ohms it would be so extremely non linear that significant errors might result Check the graph for reasonableness and then dismiss it Proceed with downloading the curve to the instrument Once complete check and verify the result The curve may be uploaded from the controller by using the Operations gt Sensor Curve gt Upload function of the utility software Or it may be manually checked from the controller s front panel by pressing the Sensors key 79 Cryo con Model 24C Basic Setup and Operation Autotuning The Autotune Process In performing autotuning the Model 24C applies a generated waveform to the heater output and analyzes the resulting changes in process temperature This is used to develop a process model then a PID solution It is important to note that a range of PID combinations exist which provide accurate control for a given process Furthermore process mode
121. esearch Triangle Park NC 27709 158 Cryo con Model 24C Appendix E Sensor Data Appendix E Sensor Data Cryo con S700 Silicon Diode The Cryo con S700 Silicon diode sensor with a 10uA excitation current Volts 1 0 1633 2 0 1733 3 0 1834 4 0 1935 5 0 2038 6 0 2141 7 0 2246 8 0 2351 9 0 2458 10 0 2565 11 0 2673 12 0 2781 13 0 2891 14 0 3001 L5 20 3111 16 0 3222 17 0 3334 18 0 3446 19 0 3558 20 0 3671 21 0 3784 22 0 3897 23 0 4011 24 0 4125 25 0 4239 26 0 4353 27 0 4467 28 0 4581 29 0 4695 30 0 4808 31 0 4922 32 0 5035 33 0 5148 34 0 5261 35 0 5373 36 0 5485 36 0 5596 38 0 5707 39 0 5900 40 0 6131 Temp K 4 4 4 4 4 4 4 75 470 465 60 55 50 445 440 35 30 25 420 415 10 05 400 39D 390 385 380 ERR 370 365 360 355 350 345 340 335 330 325 320 315 310 305 300 299 290 280 270 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 Volts 6393 6586 6807 7040 7238 7461 7682 7916 8133 8338 8547 8753 8977 9198 9373 9542 9768
122. ess to any value between 1 and 31 The address is set to 12 when the unit is shipped from the factory The GPIB interface does not use a termination character or EOS Rather it uses the EOI hardware handshake method to signal the end of a line Therefore the host must be configured to talk to the instrument using EOI and no EOS Primary Address Secondary Address Terminate Read on EOS Set EOI with EOS on Writes YES EOS byte N A Table 37 GPIB Host Setup Parameters 103 Cryo con Model 24C Remote Operation RS 232 Configuration The RS 232 interface supports baud rates of 9600 19 200 38 400 57 600 and 115200 The factory default is 9600 The baud rate is changeable from the instrument s front panel by using the System Functions Menu Other RS 232 communications parameters are fixed in the instrument They are set as follows Parity None Bits 8 Stop Bits 1 Mode Half Duplex The RS 232 interface interface uses a New Line or Line Feed character as a line termination In LabView or the C programming language this character is in or hexadecimal OxA The controller will always return the In character at the end of each line Note Some serial port software drivers allow the programmer to set a line termination character This character is then appended to each string sent to the controller and stripped from returned strings In this case the In OxA character should be selected USB option
123. et the desired ramp rate in the Heater Configuration Menu Then set the loop setpoint to the starting value for the ramp The best way to view a temperature ramp is from the control loop status Press Loop 1 key to view a screen like this Loop 1A Sample Holder Set Pt 180 000K A 175 234K Here the instrument is not Pgain 5 0000 1 Off Low Htr Off Igain 120 00S controlling temperature Dgain 0 0000 S Range HI and the ramp will start at Pman 5 0000 PID Table index 1 180K Type Ramp Htr Load 50Q Input ChA Next When the Control button is pressed the controller will go to the setpoint and control temperature there It is ing Loop 1A Sample Holder NOT yet ramping The Set Pt 180 000K A 180 000K display will look like this Pgain 5 0000 51 HI mmm Igain 120 005 Dgain 0 0000 S Range HI Pman 5 0000 PID Table index 1 Type RamP Htr Load 509 Input ChA Next Controlling at 180K but NOT ramping 86 Cryo con Model 24C Basic Setup and Operation Now you can begin ramping by changing the setpoint to the end of the ramp The display will indicate that a ramp is in progress In this example the setpoint was changed to 190 and the controller is ramping from 180 000 Notice that the loop status area now indicates a ramp is in progress The Ramp Pt field shows where the ramp should be and is continuously updated until Loop 1A Sample Holder the new setpoint is Set Pt 190 000K A 181 234K attained T
124. ets in the resistance bridge can cause additional power dissipation at low excitation levels The Model 24C holds offsets to a maximum of one half of the minimum excitation current by use of an offset cancellation feedback loop Error Sources in NTC Sensor Measurements At warm temperatures the major source of error with NTC sensors is the measurement electronics itself In a well designed instrument accuracy is limited to a level established by the measurement s signal to noise ratio where the signal is the power dissipated in the sensor and noise is the collection of all noise sources Thus accuracy is generally improved by increasing the power dissipated in the sensor Conversely at low temperature NTC resistors have high resistance and the primary source of error is sensor self heating caused by excitation power The resistor has high sensitivity in this region so measurement errors are small when viewed in units of temperature Constant voltage sensor excitation increases signal power at warm temperature thereby improving measurement accuracy in an area where the sensor is less sensitive At low temperature constant voltage excitation reduces the power dissipated in the sensor which reduces accuracy in units of Ohms but more importantly reduces sensor self heating Since low temperature is the sensor s most sensitive area temperature measurement accuracy will not be degraded The result is an accuracy improvement that extends the use
125. f the user configurable parameters for the selected control loop The Loop 1 menu is used to Loop 1A Sample Holder perform the setup of the Set Pt 300 000K A 1 234K primary 25 50 Watt heater Pgain 5 0000 1 Off Low Htr Off oi Igain 60 000S output This display was Dgain 7 5000 S Range LOW designed to provide all of the Pman 5 0000 PID Table index 1 j j Type Man Htr Load 500 information required to tune Input ChA Ge heater parameters and is rather complex Loop 1 and 2 menus can be accessed directly from the front panel Loop 3 and 4 can be accessed by first pressing the Options key When the cursor is on the top line the user can scroll through all of the control loop menus by pressing the or 0 keys Loop 3D Booster Supply Set Pt 300 000K D 211 234K Pgain 5 0000 3 Off Low Htr Off Igain 60 000S Dgain 7 5000 S Range 10VDC Pman 5 0000 PID Table index 1 Type Man Htr Load N A Input ChD Next 54 Cryo con Model 24C Front Panel Menu Operation Loop Configuration Menu a Indicator of the controlling input channel and it s E 3 1 Off LOW Htr Off Status indicator for the control loop 4 Pgain 25 0000 Proportional gain or P term for PID control 5 Igain 71 0000S Integrator gain term in Seconds for PID control Table 19 Control Loop Setup Menus E Dgai n 71 0000 S me laa gain term in inverse Seconds for PID Setpoint Numeric Entry In the first line of this menu
126. field A typical display is FW Ver 3 00D meaning that the instrument has firmware revision 3 00 and hardware revision D The name of the hex file is used to identify the firmware update update For example M24C_301 hex specifies that this is revision 3 01 for a Model 24C with hardware revision C Note The flash loader software does NOT check the hex file for compatibility with the target instrument Please be sure that you are using the correct file Connecting a PC to the instrument It is recommended that the instrument is connected directly to a PC using a LAN Crossover cable The standard LAN patch cable is designed to connect a PC to a hub and will not work when used to connect to an instrument The Crossover cable has the transmit and receive lines reversed which allows direct connection to an instrument These cables should be clearly marked with the word Crossover From the PC open the network connections dialog select the network adapter that you are using with the Cryo con instrument and select Internet Protocol TCP IP In the TCP IP dialog box select Use the following IP addresses and enter following IP address 192 168 1 10 Subnet mask 255 255 255 0 Other fields are not used Click OK This should allow you to communicate with the instrument The advanced user can configure the Ethernet connection in any convenient way The above procedure is given because it is known to work The instrument wi
127. ful temperature range of a given sensor at both the warm and cold ends 74 Cryo con Model 24C Basic Setup and Operation NTC Sensor Configuration NTC sensors are configured by first going to the input channel menu selecting a NTC sensor and then selecting the Input Config field An example NTC Input Configuration menu is shown here A Cryo con R500 sensor KEES was selected Temperature and sensor Bl WM i ga ee 10mV EES 17666710W power dissipation are Bridge Range Auto shown in real time Temperature units can be changed in the real time temperature display field The asterisk character next to the sensor resistance reading indicates that the resistance bridge is not locked This may indicate that it is still autoranging or that the sensor resistance is too high or too low for the selected voltage bias Voltage bias levels are 10mV 3 0mV 1 0mV and 300uV Higher voltages improve accuracy at warm temperature and lower levels reduce self heating at cold temperature The user must select a level that maximizes accuracy over the desired temperature range Generally sensors operating above about 2K use the 10mV setting Below that selection is more difficult because it depends on the sensor resistance and thermal design To select a voltage bias in the low temperature region 1 Establish the sensor at the lowest possible temperature and use the lowest value of bias voltage that will read the sensor s resistance 2
128. gnal will be seen up by sensitive measurement equipment in the system Turning AC excitation Off will eliminate this noise at the cost of introducing a DC offset measurement error 76 Cryo con Model 24C Basic Setup and Operation Downloading a Sensor Calibration Curve The Model 24C accommodates up to eight user defined sensor calibration curves that can be used for custom or calibrated sensors Since these curves have up to 200 entries they are usually maintained on a computer as a text file and downloaded to the controller by using the Cryo con Utility Software However curve data may also be entered and edited from the front panel Cryo con sensor calibration curves have a file extension of crv They may be opened and edited with any text editor The format of the file is detailed in Appendix A The process for downloading a sensor calibration curve using the Cryo con utility software is detailed in the section titled Downloading or Uploading a Sensor Calibration Curve This section discusses how to set up a curve specifically for download to the Model 24C The Cryo con utility software will read and attempt to parse the following file types Sensor Curve File Types Directly supported Supported Reads curve data Header information must be Lakeshore 340 entered by using the header dialog box The Cryo con utility software will convert these files into crv format automatically SI txt No header information Columns ar
129. h a very low heat capacity load The first part of the graph is with the synchronous filter turned off and the second part shows a setting of 11 taps In most cases a tap setting may be found that completely eliminates the signature Channel A 90 Cryo con Model 24C Basic Setup and Operation Using an external power booster Some systems require more power than the Model 24C can provide or require a higher power secondary control loop An auxiliary DC power supply or amplifier can be used for this purpose The non powered control loops 3 and 4 are designed to drive power supplies that can be programmed by an input voltage Two output ranges of DV or 10V are provided to match the inputs of most supplies Further either of the Model Model 24C relays can be used to turn the supply on or off To configure a supply simply go to the loop 3 or 4 configuration menu and select a voltage range that matches the supply input requirements All of the other configuration parameters work the same as they do for loop 1 and 2 To configure a relay to turn the external supply on or off go to the relay configuration menu and select a mode of Control In this mode the relay will be asserted whenever the instrument is in Control mode Power supplies designed for Automatic Test Equipment ATE usually have a remote on off capability that can be controlled by one of the Model 24C s relays To do this set the relay mode to Contr
130. he current status of a selected control loop The control loop s input temperature is shown in 2x font Above is the loop and channel indicator the input channel s name string and alarm status Below in 1x font is the loop s setpoint heater range and percent of full scale output power Input Channel Statistics Display The Channel A B C and D statistics displays show the selected input channel temperature the slope of the temperature history the minimum and maximum temperatures The slope of the temperature history M is given in Display Units per Minute When any of the statistics pages are displayed pressing the Enter key will reset the accumulation 46 Cryo con Model 24C Front Panel Operation Temperature Displays Atypical Input Channel Temperature Display is shown on this page It consists of the input channel designator a Temperature reading and the current temperature units The temperature a seven character field is affected by the Display Resolution etting in the System menu This setting may be 1 2 3 or Full Settings of 1 2 or 3 indicate the number of digits to the right of the decimal point to display whereas the Full setting causes the display to be left justified in order to show the maximum number of significant digits possible The Display Resolution setting does not affect the internal accuracy of arithmetic operations It is generally used to eliminate the display of unnecessary digits that are beyo
131. he input Fgain 5 0000 Ramp HI mmm p Igain 120 00S Ramp Pt 181 110 temperature should track Dgain 0 0000 S Range HI the Ram Pt field Pran SE PID Table index 1 indicating that the ramp is Input ChA ner coad 509 progressing as it should Ramping to 190K Ramping will continue until the setpoint is attained Then the loop status will return to normal PID control and the controller will maintain the Loop 1A Sample Holder setpoint Set Pt 190 000K A 190 000K Pgain 5 0000 58 HI mmEE Igain 120 00S f Dgain 0 0000 S Range HI From here each time you Pman 5 0000 PID Table index 1 change the setpoint the Type RamP g mS Sorp LEI ChA Htr Load 500 controller will ramp to the Next new value and control temperature there Ramp complete Controlling at 190K Summary To perform a temperature ramp proceed as follows 1 Set the control loop P and D parameters to allow stable control at both ends of the desired ramp This is usually done by using slow PID values Low values for P high for and zero for D 2 Set the Ramp Rate in the Heater Configuration Menu Set the setpoint to the starting value for the ramp 3 Press CONTROL Now the controller will begin temperature regulation at the current setpoint 4 Enter a new setpoint The controller will enter ramping mode and ramp to the target setpoint at the specified rate The word RMP will appear in the control loop menu 5 When the new set
132. he unit off and refer to Appendix C Troubleshooting Guide Caution Do not remove the instrument s cover or attempt to repair the controller There are no user serviceable parts jumpers or switches inside the unit Further there are no software ROM chips trim pots batteries or battery backed memories All firmware installation and instrument calibration functions are performed externally via the remote interfaces After about fifteen seconds the self test will complete and the controller will begin normal operation Cryo con Model 24C Preparing the controller for use Installation General The Model 24C can be used as a bench top instrument or mounted in an equipment rack In either case it is important to ensure that adequate ventilation is provided Cooling airflow enters through the side holes and exhausts out the fan on the rear panel It is important to allow at least Y of clearance on the left and right sides and to ensure that the exhaust path of the fan is not blocked Rack Mounting You can rack mount the controller in a standard 19 inch rack cabinet using the optional rack mount kit Instructions and mounting hardware are included with the kit 4122 030 Single instrument 2U rack mount kit 4034 032 Single instrument shelf rack mount kit 4034 031 Dual instrument shelf rack mount kit Figure 1 4122 030 Rack Mount Kit Cryo con Model 24C Preparing the controller for use Using the one or two i
133. heater output values in terms of percent of full scale output power The actual power in Watts applied to the load is proportional to the square root of output current Control Source Input Channel Enumeration The input filed selects the control loop source input Any input channel may be selected Control Loop Range Enumeration Default Low The Range field selects the full scale output for the selected control loop 56 Cryo con Model 24C Front Panel Menu Operation Control Types Enumeration Default Man The Type filed selects the actual control algorithm used for the selected loop Loop control modes are 1 Man for Manual control mode Here a constant heater output power is applied when the unit is controlling temperature The Pman field selects the output as a percentage of full scale 2 Table This is a PID control mode where the PID coefficients are generated from a stored PID table based on setpoint 3 PID for standard PID control 4 Off In this mode the controller will not apply power on this output channel Note that the Model 24C is a dual loop controller The Off control mode is used if regulation is desired only on the other channel 5 RampP This is a temperature ramp mode When a ramp operation is complete the controller will revert to standard PID mode control at the final setpoint 6 RampT This is a temperature ramp mode that uses the PID tables to generate tuning parameters For
134. hes material is 37 AWG copper with Polyimide insulation Positive connection is Red and negative is Black Sensor is easily installed by attaching the 1 we j substrate directly to the desired surface using cryogenic varnish Leads should be thermally as anchored E The CP is an ultra compact Ch It features low thermal mass and operation to 500K 0 042 Package material is gold plated OHFC copper AE Leads are 3 inches Material is 37 AWG copper with Polyimide insulation Positive connection is Red and negative is Black This package is extremely small and has a low thermal mass 163 Cryo con Model 24C Appendix E Sensor Data The BB Sensor Package The BB package is an industry standard 0 310 bobbin package that features excellent thermal contact to the internal sensing element This ensures a rapid thermal response and minimizes thermal gradients between the sensing element and the sensor package Mechanical integrity of the sensor assures reliable performance even in severe applications With the bobbin package the lead wires are thermally anchored to the sensor mounting This is essential for accurate sensor readings CSI ATTE 36 inches 36AWG Phosphor Bronze Four lead color coded cryogenic ribbon cable Insulation is heavy Formvar Mounting 4 40 machine screw Table 38 BB Package Specifications Connections to the BB package are made using a color coded four wire 36 A
135. his case the Integral term is just the inverse of the Reset value The Derivative or D gain term is in units of inverse Seconds and should be the same for various controllers Using Factory Default PID values Controllers are shipped from the factory with very conservative PID values They will give stable control in a wide range of systems but will have very slow response times Often the factory values provide a good start for the autotune process The values are P 0 1 I 5 0 and D 0 0 Autotuning Autotuning is the easiest way to obtain PID values or optimize existing ones Please review the Autotuning section of this manual Manual Tuning The final and most laborious method of tuning a control loop is manual tuning This involves generating values for P and D by observing the system s response to the stimulus of the heater output 157 Cryo con Model 24C Appendix D Tuning Control Loops Various methods of manually tuning the controller are described below Manual Tuning Procedures Manually tuning a PID control loop is relatively simple It is greatly assisted by use of a data logging program such as the Cryo con utility software package described in the Cryo con Utility Software section Ziegler Nichols Frequency Response Method This method is based on the assumption that a critically damped system is optimal and the fact that stability and noise must be traded for response time It requires driving your syste
136. if the bridge is unlocked If the bridge is unlocked it is still searching for a balance point The sensor reading will be correct but the excitation current and power dissipation will be incorrect INPut A B C D ALARm Queries the alarm status of the specified input channel Status is a two character string where indicates that no alarms are asserted SF indicates a Sensor Fault condition HI indicates a high temperature alarm LO indicates a low temperature alarm The user selectable display time constant filter is applied to input channel temperature data before alarm conditions are tested INPut A B C D ALARm HIGHest lt setpt gt Sets or queries the temperature setting of the high temperature alarm for the specified input channel When this temperature is exceeded an enabled high temperature alarm condition is asserted INPut A B C D ALARm LOWEst lt setpt gt Sets or queries the temperature setting of the low temperature alarm for the specified input channel When the input channel temperature is below this an enabled low temperature alarm condition is asserted Temperature is assumed to be in the display units of the selected input channel INPut A B C D ALARm DEAdband lt setpt gt Sets or queries the dead band setting Dead band is assumed to be in the display units of the selected input channel INPut A B C D ALARm HIENa YES NO Sets or queries the high temperature alarm enable for the specified input channel An
137. inuity between the sensor connection and ground Review the System Shielding and Grounding Issues section Note Cryo con controllers use a shielding scheme that is slightly different than some other controllers If you are using cable sets made for use with other controllers some shield connections may need to change If pin 3 of the input connector is connected to the cable shield disconnect it and either re connect the shield to the backshell contact or leave the shield floating No connection should ever be made to pin 3 of the input connector Check for shielding problems by temporarily removing the input connector s backshell If the noise changes significantly current is being carried by the shields and is being coupled into the controller Use a longer display filter time constant to reduce displayed noise 153 Cryo con Model 24C Appendix C Troubleshooting Guide Symptom DC offset in temperature Possible causes measurements 1 The wrong sensor type or sensor calibration curve is being used Refer to the Input Channel Configuration Menu section DC offset in cryostat wiring Review the Thermal EMF and AC Bias Issues section Use AC bias if necessary to cancel the offset error A four wire measurement is not being used Some cryostats use a to a two wire measurement internally This can cause offset errors due to lead resistance Thermocouples These sensors will often have DC offset errors Use offse
138. ions Features and Functions Input Channel Characteristics There are four independent multi purpose input channels each of which can separately be configured for use with any supported sensor Input Configurations A complete list of the sensor types supported by the Model 24C is shown below Sensor Typ Max Voltage Bias Excitation Typical Use yp Resistance Type Current yp 2 25V 104A DC Silicon diode GaAs diode 2 5mA 10nA NTC resistors including Ruthenium PTC100 0 5 5000 1 0mAAC 1000 Platinum Rhodium Iron Tee ew CI Dee inma 0 teat reference temperature one 0 Nene 0 Disable Input Channel Table 10 Supported Sensor Configurations Bias types are CI Bridge maintains a constant current through the sensor CV Bridge maintains a constant voltage drop across the sensor O Note Any disconnected inputs to the Model 24C should be set to type None This will turn the input off Specialized Sensors The sensor type Internal reads an internal temperature sensor located near the instrument s primary voltage reference This measurement is useful to track variations in internal temperature for correlation with external events It can also be used to set alarms for when the ambient temperature is outside the range where your measurements are at specified accuracy Silicon Diode Sensors Silicon diode sensors 2 volt diodes are configured with a 10uA current source excitation and a 2 25
139. l 5 0 10 Range MAR MAT 7 SenSen MAR is the electronic Measurement Accuracy in Ohms Range is the resistance range in Ohms 100 1K or 10K MAT is the Measurement Accuracy in Kelvin SenVal is the sensor reading in Ohms at the desired temperature SenSen is the sensor sensitivity in Ohms Kelvin at the desired temperature To calculate the measurement accuracy of the Model 22C using a Cryo con R500 Ruthenium Oxide sensor in the 1KQ range with the sensor at 1 0K look up the sensor reading and sensitivity in Appendix G SenVal is 23270 and SenSen is 1203Q Kelvin Therefore the computed values equal MAR 0 170 and MAT 100uK 28 Cryo con Model 24C Specifications Features and Functions Measurement Resolution and Control Stability The input analog to digital converter used by the Model 22C is 24 bits with no missing codes Thus the measurement resolution is identifiable as one part in 271 However the only use for measurement resolution is to compute control stability Since control stability is limited by the output DAC rather than the input the measurement resolution specification is limited to one part in 2 MR FullScale 2 7 Where MR SenSen MR is the electronic measurement resolution in sensor units FullScale is the full scale range MRT is the measurement resolution in temperature units SenSen is the sensor sensitivity at the measurement point MRT 29 Cryo con Model 24C Specificat
140. lection of a heater resistance that is much greater than the actual heater resistance Refer to the Control Loop Setup menu section Selection of an AC Power line voltage that is much less than the actual voltage Refer to the Fuse Replacement and Voltage Selection section Check that the instrument s fan is running and that the sides and rear panel allow easy air flow Readback displayed The control loops were disengaged by the heater current read back monitor Most likely cause is an open heater SensorFLT displayed The control loops were disengaged by a sensor fault condition Correct the input sensor fault condition to proceed The control loops will only engage when there is a valid temperature reading on their input The exception is when a loop is assigned a control mode of Off or Manual OTDisconn displayed The control loops were disengaged by the Over Temperature Disconnect monitor This was done to protect user equipment from damage due to overheating To configure the monitor refer to the System Functions Menu section The heater output current This is normal and does not indicate unstable heater power The output monitor is jumping up current monitor is coarsely quantized and is displayed only for an and down by about 1 indication of proper function The controller should be The output indicated on the display is the actual measured output power applying power but the of the control loop A reading of 0 while the contro
141. line TFT LCD and a keypad All features and functions of the instrument are accessed via this simple and intuitive menu driven interface ChA ChB che Ch Mt Esc Options Loop1 Loop 2 Mis Ce PID Auto Sensors Config Table Tune gt rs e System Display Alarm Set Pt Control Alarm Remote Figure 4 Model 24C Front Panel Layout The Keypad Function Keys The Function Keys on the Model 24C are Power Stop Control Home and Enter These buttons always perform the same function regardless of the context of the display _ The Power key is used to turn AC power to the controller on or off Note that this key must be pressed and held for one second in order to toggle AC power Note The Model 24C uses a smart power on off scheme When the power button on the front panel is pressed to turn the unit off the instrument s configuration is copied to flash memory and restored on the next power up If the front panel button is not used to toggle power to the instrument the user should configure the controller and cycle power from the front panel button one time This will ensure that the proper setup is restored when AC power is applied 41 Cryo con Model 24C Front Panel Operation The Stop and Control keys are used to disengage or engage the instrument s output control loops Pressing Control will immediately turn on all enabled heater outputs and pressing Stop will turn them
142. ling is a statistical method affected by noise and system non linearity Consequently multiple autotuning of the same process may yield different results However if the process model has not corrupted any of the generated results will provide equally stable temperature control For further explanation the different PID solutions generated by autotuning vary only in the resultant closed loop bandwidth Low bandwidth solutions are slower to respond to changes in setpoint or load disturbances High bandwidth solutions are responsive but can exhibit overshoot and damped oscillation The Model 24C attempts to generate minimum overshoot solutions since many cryogenic temperature control applications require this If the process is noisy bandwidth is minimized as much as possible If the process is very quiet a more aggressive solution is generated subject to the minimum overshoot requirement The autotune algorithm produces a heater output waveform in order to force the process model to converge In general a large amplitude waveform will provide the best possible signal to noise ratio resulting in a faster and more accurate solution However it is important in some systems for the user to constrain the amplitude and duration of the heater output waveform by using the DeltaP and Timeout parameters Small values for DeltaP force the use of small changes in heater power This makes the process model more susceptible to corruption by noise
143. lize the process before the autotune function can accurately model it If the process is not stable erroneous values of P and D will be generated 3 The input control channel units must be in temperature not sensor units of Volts or Ohms This is because PID control is a linear process and sensor output is generally non linear Note that the Model 24C can be manually tuned using sensor units but autotuning cannot be performed 82 Cryo con Model 24C Basic Setup and Operation Autotune Menu Sets the loop number for autotuning Each control loop must be Autotune Loop 2 tuned separately d Sets the maximum power delta allowed during the tuning process DeltaP 20 Value is a percent of full scale output power Mode PI Sets autotuning mode Choices are P PI or PID Sets the autotune timeout in seconds If the process model has Timeout 1805 not converged within this time tuning is aborted 308 112K oa display of the temperature on the input channel being Pressing Enter will initiate the autotune sequence Autotune status Display only Integral gain term generated by autotune This field will be blank until a successful autotune is completed Derivative gain term generated by autotune This field will be blank until a successful autotune is completed Pressing Enter cause the controller to transfer the generated PID Save Exit coefficients to the selected loop initiate control with the new parameters and exit
144. ll keep the assigned IP through the entire update process However when the update is complete factory defaults are restored and the IP will be set to 192 168 1 5 148 Cryo con Model 24C Appendix B Updating Instrument Firmware Loading Firmware Start the firmware update by running the Cryo con Firmware Utility This launches a dialog box as shown here The instrument s default IP will x appear in the dialog box This can be changed if necessary Firmware HEX file Click the Connect button The status El box should update to indicate a DEE connection but the instrument De we 1 5 MAN display will not change Next the firmware update file needs to be selected Click on the browse button to launch a file selection Status _ dialog Select the firmware hex file and click Open The Firmware HEX file field will be updated with the file name Also the Set Flash Mode button will become active Caution Once you click the Set Flash Mode button the instrument will enter the firmware update mode and will not function normally again until the entire firmware update process is complete without error Be sure you have the correct hex file before proceeding Click the Set Flash Mode button to set the instrument into the flash programming mode The instrument will reset and start in the flash load mode This is indicated by the display shown Since the instrument was Cryogeni
145. ller is attempting to display is showing 0 output power usually indicates an open heater output Unstable control If the system is oscillating try de tuning the PID values by decreasing P increasing and setting D to zero If the oscillations cannot be stopped by this procedure the cause is likely that your system has an excessive time delay Linear control algorithms including PID cannot control systems with excessive time delay These problems often occur in systems that use heat pipes or depend on gas flow between the heater and temperature sensor elements The only solution to such systems is to re design the equipment to reduce the time delay or to externally implement a time delay compensation algorithm such as a Smith Predictor Do not try to control on Ohms or Volts The controller will work correctly with either of these sensor units but the PID values required are significantly different and most sensors are non linear Furtherer there is no advantage to controlling in sensor units Optimize the control loop parameters by using the Autotune feature described in the Autotuning section Most cryogenic systems require significantly different PID parameters at different temperatures To ensure stable control over a wide temperature range use the PID Table feature described in the PID Table Entry section If the heater is controlling with an output power level less than 10 switch to the next lower heater range
146. m into temperature oscillation Care should be taken so that this oscillation does not cause damage Enable the Over Temperature Disconnect feature of the controller if there is concern over possible damage from overheating 1 Enter a setpoint value that is a typical for the envisaged use of the system Select a heater range that is safe for the equipment Set initial PID values of Pgain 0 1 Igain 0 and Dgain 0 2 Engage the control loops by pressing the Control key 3 Increase the Pgain term until the system is just oscillating Note the Pgain setting as the Ultimate Gain Kc and the period of oscillation as the Ultimate Period Tc 4 Set the PID values according to the following table Control Type Pgain Lei Doain pony oske o o 5 Wait for the system to stabilize If the resultant heater power output reading is less than 10 of full scale select the next lower heater range setting A range change will not require re tuning Note In systems where there is high thermal noise including cryocoolers a Dgain value of zero is often used The Dterm is a derivative action which can introduce additional noise into the control process Alternate Methods There are various other methods to manually tune PID loops Most are based on graphical techniques and all use a stimulus response technique For further reading Automatic Tuning of PID controllers Instrument Society of America 67 Alexander Dr PO Box 12277 R
147. ment firmware During the normal power up sequence the boot loader tests the external flash memory and then transfer execution to it in order to run the instrument s firmware From there the Cryo con firmware update utility can be used to update instrument s firmware The firmware update sequence is as follows 1 Connect the LAN port of the instrument to your PC turn the instrument ON and then run the FWutility exe 2 Click the Connect button to connect the PC to the instrument using TCP IP If there is an error a dialog box will appear Correct the problem and re try 3 While connected the instrument still functions normally Click on the Set Flash Mode button to place the instrument in the firmware update mode In this mode the instrument executes the boot loader from the Internal flash memory and is waiting to program the External memory with the new firmware 4 Click Connect again and then click the Program Verify button to start the update process 5 When the update process is complete the instrument will automatically reset itself and start running the updated firmware 147 Cryo con Model 24C Appendix B Updating Instrument Firmware Updating unit firmware Before starting be sure to have the FWutility exe file and a hex file that contains the desired firmware update On the instrument check the current hardware and firmware revision by pressing the System key and scrolling down to the revision
148. more information on control algorithms refer to the Heater Control Types table above For more information on temperature ramps refer to the section on Temperature Ramping below Output Power Limit Numeric entry Default 100 The Power Limit field defines the maximum output power that the controller is allowed to output It is a percent of the maximum allowed output Maximum value is 100 and minimum is 15 The Power Limit is applied to the HI range only Note Output Power Limit is an important cryostat protection feature The user is encouraged to apply it Maximum Setpoint Numeric Entry Default 1000K The Maximum Setpoint field is used to prevent the casual user from inadvertently entering a temperature that might damage the cryostat Maximum value is 10 000K and minimum is 0 K Setpoint values use the temperature units selected for the controlling input channel See the section on Temperature Displays Note The Maximum Setpoint selection is an important cryostat protection feature The user is encouraged to apply it PID Table Index Numeric entry Default 0 The PID Table index line is used to identify the number of the user supplied PID Table that will be used when the Table control mode is selected The Model 24C will store up to six PID Tables They are numbered zero through five 57 Cryo con Model 24C Front Panel Menu Operation Heater Resistance Enumeration Default 250 The heater re
149. n the temperature reading of a selected input channel High and low setpoints may be set from the front panel or a remote interface Furthermore the relays can be manually asserted ON or OFF Remote Control Standard Remote Interfaces include Ethernet and RS 232 IEEE 488 2 GPIB and USB are optional The Model 24C connects directly to any Ethernet Local Area Network LAN to make measurements easily and economically TCP IP and UDP data port servers brings fast Ethernet connectivity to all common data acquisition software programs including LabView An ASCII text based command language identical to those commonly used with GPIB or RS 232 interfaces is implemented This is the primary way that user software interfaces to the instrument Using the Ethernet SMTP protocol the controller will send e mail based on selected alarm conditions E mail is configured by using the web page interface Using the Ethernet HTTP protocol the instrument s embedded web server allows the instrument to be viewed and configured from any web browser Cryo con Model 24C Introduction Cryo con Model 24C Home Status Windows Internet Explorer loj x rE mesan RA Cryo con Model 24C Cryogenic Temperature Controller Temperature Ch A Channel A 261 212 K Ch B Channel B 306 612 K Ch C Channel C 352 012 K Ch D Channel D 397 412 K Control L aah coat Channel A 300 000K Htr Off Channel B 100 000K Htr Off Channel C
150. nd is clear Control Relay is asserted whenever the controller is in Control mode Useful in controlling external booster supplies Table 29 Digital Output Modes 71 Cryo con Model 24C Basic Setup and Operation Basic Setup and Operation Configuring a Sensor Before connecting a new sensor to the Model 24C the instrument should be configured to support it Most common sensors are factory installed while others require a simple configuration sequence A complete list of sensors installed at the factory is shown in Appendix A To configure the instrument for one of these sensors proceed as follows 1 To install the sensor on Input Channel A press the ChA key For Channel B press the ChB key etc This will take you to the Input Channel Setup menu for the selected channel The first line of this display will show the current temperature in real time and allow you to select the desired display units Press the or 0 keys to sequence through the available options and press the Enter key to make the selection Use the navigation keys to go down to the Sen filed Press the or 0 keys to scroll through all of the sensor types available When the desired sensor is displayed press the Enter key to configure the instrument Select None to disable the input channel At the end of the factory installed sensors eight user installed selections will be shown The default name for these are User Sensor N However
151. nd the sensor s actual resolution If the Input Channel has been disabled a blank display is shown Fahrenheit Temperature units are selected in the individual input channel setup menus ChA ChB ChC or ChD Temperature Units may be K C or F milli Volts When Sensor Units S is selected the raw input f readings are exhibited These will be in Volts or Table 16 Temperature Units Ohms Sensor Fault Display A sensor fault condition is identified by a temperature display of seven dash characters as shown here The sensor is open disconnected or K shorted Temperature Out of Range Display If a temperature reading is within the measurement range of the instrument but is not within the specified Sensor Calibration Curve a display of seven dot aerem characters is shown LS Note In some cases there will be an erratic temperature display when no sensor is connected This is not an error condition The high input impedance of the controller s input preamplifier causes erratic voltage values when left unconnected If an input is left unconnected the sensor type should be set to type None which turns the input off 47 Cryo con Model 24C Front Panel Operation Loop Status Displays An example of the loop status display on the home screen is shown here The 1A in the upper left corner indicates the status of Loop 1 with a source input channel of A The bottom line shows 14
152. ndix E Sensor Data Cryo con S900 Silicon Diode The Cryo con S900 Silicon diode sensor with a 10uA excitation current Volts Temp K Volts Temp K Volts Temp K 0 09077 500 00 0 86921 160 00 1 06858 52 00 0 09281 499 00 0 87959 155 00 1 07023 51 00 0 11153 490 00 0 88988 150 00 1 07188 50 00 0 13320 480 00 0 90008 145 00 1 07353 49 00 0 15565 470 00 0 91021 140 00 1 07517 48 00 0 17873 460 00 0 92022 135 00 1 07681 47 00 0 20231 450 00 0 93008 130 00 1 07844 46 00 0 22623 440 00 0 93976 125 00 1 08008 45 00 0 25016 430 00 0 94927 120 00 1 08171 44 00 0 27403 420 00 0 95867 115 00 1 08334 43 00 0 29785 410 00 0 96794 110 00 1 08497 42 00 0 32161 400 00 0 97710 105 00 1 08659 41 00 0 34532 390 00 0 98615 100 00 1 08821 40 00 0 34768 389 00 0 99510 95 00 1 08983 39 00 0 36898 380 00 1 00393 90 00 1 09145 38 00 0 39261 370 00 1 00569 89 00 1 09306 37 00 0 41620 360 00 1 00744 88 00 1 09468 36 00 0 43976 350 00 1 00918 87 00 1 09629 35 00 0 46330 340 00 1 01093 86 00 1 09791 34 00 0 48681 330 00 1 01267 85 00 1 09952 33 00 0 51024 320 00 1 01439 84 00 1 10124 32 00 0 52192 315 00 1 01612 83 00 1 10295 31 00 0 53356 310 00 1 01785 82 00 1 10465 30 00 0 54516 305 00 1 01957 81 00 1 10643 29 00 0 55674 300 00 1 02127 80 00 1 10828 28 00 0 56828 295 00 1 02299 79 00 1 10996 27 00 0 57980 290 00 1 02471 78 00 1 11217 26 00 0 59131 285 00 1 02642 77 00 1 11480 25 00 0 60279 280 00 1 02814 76 00 1 11828 24 00 0 61427 275 00 1 02985 75 00 1 12425
153. nge from idle to Running If initialization is not successful one of the above listed conditions has not been met Waiting for input temperature and output power to stabilize Running Actively autotuning Complete Successful completion Failed due to processing error Usually this is because the process model did not converge Try a smaller DeltaP setting Abort e Aborted by the user Table 32 Autotune States Note When autotuning is initiated the algorithm will stay in the Stabilize state until the output power and the input temperature are stable Time in this state is not part of the selected timeout If the system is not stable the autotuning process will stay in the Stabilize state indefinitely To abort press the Home key 84 Cryo con Model 24C Basic Setup and Operation When the tuning process is successfully completed a status of Complete will be indicated and the values of P and D will be updated with the generated values To accept these values and save them as the loop PID coefficients select the Save amp Exit field To reject the values and exit press the ESC key Autotune may always be aborted by pressing the ESC key An unsuccessful autotune is indicated by one of the following status lines 1 Failed This indicates that the process model did not converge or that PID values could not be generated from the result 2 Aborted Autotune was aborted by user interv
154. nstrument shelf rack mount kit additional equipment may be mounted on the shelf space next to the controller Note that these rack mount kits extends the height of the controller from 2U 372 to 3U 5 Since the controller is an industry standard size it is possible to mount any similar size instrument next to it in the rack Figure 2 4034 032 Rack Mount Kit Warning When using the shelf type rack mount kits do not use screws that protrude into the bottom of instrument more than Y Otherwise they can touch internal circuitry and damage it 10 Cryo con Model 24C Preparing the controller for use Initial Setup and Configuration Before attempting to control temperature the following instrument parameters should be checked 1 The Loop 1 Heater resistance setting should match the actual heater resistance that you are going to use Choices are 500 and 250 A heater resistance of less than 25Q should use the 250 setting Using the 50Q setting with a heater resistance much less than 500 may cause the instrument to overheat and disengage the control loops Set the heater resistance by pressing the Loop 1 key and refer to the Loop Configuration Menu section The Loop 1 heater range should be set to a range where the maximum output power will not damage the equipment To set this parameter press the Loop 1 key and refer to the Loop Configuration Menu section The controller has an over temperature disconnect feat
155. nt is a 10 Hz square wave This square wave excitation generates a small noise signal in the sensor cable which can be picked up by sensitive measurement equipment in the system Turning AC excitation Off will eliminate this noise at the cost of introducing a thermal EMF DC offset voltage into the sensor measurement 31 Cryo con Model 24C Specifications Features and Functions NTC Resistor Sensors The Model 24C supports almost all types of Negative Temperature Coefficient NTC resistive sensors by using a constant voltage AC resistance bridge technique these sensors can be used down to very low temperatures Examples of NTC resistor sensors include Ruthenium Oxide Cernox Carbon Glass Germanium and other thermistors Constant voltage excitation is necessary since the resistance thermometers used below about 10K exhibit a negative temperature coefficient Therefore a constant voltage measurement reduces the power dissipation in the sensor as temperature decreases By maintaining low power levels sensor self heating errors that occur at very low temperatures are minimized For more information on using the Model 24C with NTC resistor sensors please refer to the section titled Voltage Bias Selection Power dissipation in the sensor is computed by 2 y 8 bias P bias sensor The actual power being dissipated in the sensor may be viewed in real time by going to the Input Configuration Menu An asterisk cha
156. numeric fields will be deleted PIDTable lt index gt Queries the name string of a PID table at a specified index PIDTable lt index gt NAMe Sets or queries the name string of the PID Table at a specified index The Name name string is used to associate a convenient name with a PID table It may include up to 15 ASCII characters PIDTable lt index gt NENTry Queries the number of entries in a PID Table This number is generated from the table itself and cannot be changed using this command PIDTable lt index gt TABLe Uploads or downloads a complete PID table Transfer will end on a line containing a single semi colon 135 Cryo con Model 24C Remote Programming Guide Network Commands The following commands are used to configure the Model 24C s Ethernet interface NETWork IPADdress IPA Sets or queries the controller s IP address The address is expressed as an ASCII string so the input parameter must be enclosed in quotes For example the default IP address parameter is 192 168 1 5 NETWork PORT port number gt Sets or queries the controller s TCP port number Default is 5000 NETWork NAMe Name Sets or queries the controller s network name This name is expressed as an ASCII string so the input parameter must be enclosed in quotes Maximum of 15 characters NETWork DHCP ON OFF Sets or queries the controller s DHCP status NETWork MACADdress Queries the controller s MAC address The add
157. ny unauthorized modification to the product For service or repair return the product to Cryo con or an authorized service center Cryo con Model 24C Table of Contents liegen 1 Sensor le 1 Control LOOPS criolla EEN 2 UserinterfaCe ici aio 2 Remote Control 4 Preparing the controller for use 7 Supplied tems simio ee tee vie inde edit eee 7 Verify the AC Power Line Voltage Gelechon 7 Apply Power to the Controller ccccceeeeeeeeeeeeeeneneceeeeeeeeeeeeteeeesenaaa 8 EE UE e EE 9 Initial Setup and Confguraton nn cr cnn 11 A Quick Start Guide to the User lntertace renent 17 Specifications Features and Funchons 21 Specification Gummanm nrinn erk EnEn naa 21 Performance SUMMA areosos vinnin aeeie pa iaa aat 27 Input Channel Charachertetce nnn nneenen nren 30 Control Loop Outputs eiiis na aaa e STEE 34 Remote Interfaces eae teada tanaka raro taeda ee aeae eKA Een a ET aa A Enae 36 Rear ln TE 37 Mechanical Form Factors and Enmvironmental 0 nneeoeannneenneennnnnena 38 Front Panel Operation 41 The Keypad ica eet 41 The Front Panel Display cata td tc 46 Front Panel Menu Operation 51 Instrument Setup Menus nr renee nenne 51 Basic Setup and Operation 73 Configuring A SENSO ognirnar tn a qaiads 73 its fr Me EE 74 Using PTC resistor sensorg 76 Downloading a Sensor Calibration Cumve 77 AUNING DEE 80 Temperature Ramping meierier aeneis siar aoia 85 Cryocooler Signature Gubtrachon 88 U
158. of the reading SYSTem HOMe Causes the front panel display to go to the Operate Screen SYSTem SYNCtaps lt taps gt Sets or queries the number of taps in the synchronous filter This is an advanced setup function The default is 7 taps SYSTEM NAME name The controller contains a unit name string that may be set or queried using this command This can be used to assign a descriptive name to the instrument SYSTem HWRev Queries the instrument s hardware revision level SYSTem FWREV Queries the instrument s firmware revision level SYSTem LINefreq 60 50 Sets or queries the AC Power Line frequency setting which may be either 50 or 60 for 50Hz or 60Hz Command only affects the operation of the synchronous cryo cooler filter 121 Cryo con Model 24C Remote Programming Guide SYSTem DRES FULL 1 2 3 Sets or queries the controller s display resolution Choices are e FULL The display will show numbers with the maximum possible resolution e 1 2or3 The display will show the specified number of digits to the right of the decimal point NOTE This command only sets the number of digits displayed on the front panel display It does NOT affect the internal accuracy of the instrument or the format of measurements reported on the remote interfaces The main use for this command is to eliminate the flicker in low order digits when the controller is used in a noisy environment SYSTem PUControl ON OFF Sets
159. ol In this mode the relay will assert whenever the Model 24C is controlling temperature and will otherwise clear Using CalGen The CalGen feature is used to generate new calibration curves for Silicon diode thermocouple or Platinum sensors This provides a method for obtaining higher accuracy temperature measurements without expensive sensor calibrations Most Cryo con temperature controllers support CalGen directly on the instrument However the utility software package implements the same algorithm and can be used with virtually any instrument capable of measuring temperature Curves can be generated from any user selected sensor calibration curve and are written to a specified internal user curve location For diode sensors the user may specify one two or three data points CalGen generates the new curve based on fitting the input curve to the user specified points Platinum or thermocouple calibration curves require one or two data points The generated curve is a best fit of the input curve to the two specified input points Since CalGen fits a sensor calibration curve to measured data any errors in the measurement electronics are also effectively canceled O Note CalGen is re entrant Therefore the user can enter or exit the CalGen menus at any time without loss of previously captured data points For example a data point may be captured near 300K next the user may exit the CalGen process in order to stabilize the controller n
160. onstant Current AC excitation Q K Ohms nei 4 15 220 0 24 45 229 73 0 24 75 236 91 0 24 105 244 08 0 24 195 265 6 0 24 250 278 75 0 24 273 15 295 71 0 24 300 290 71 0 24 175 Cryo con Model 24C Appendix G Sensor Data Tables Cernox Cernox temperature sensors do not follow a standard calibration curve Data T K Ohms QK shown here is for typical sensors 03 31312 357490 The Model 24C supports Cernox using 0 4 13507 89651 a 10mV or less Constant Voltage AC 05 7855 7 34613 excitation Please refer to the section 1 23554 3265 2 titled Voltage Bias Selection 14 1540 1 1264 9 2X 1010 2 1058 4 509 26 Se ai 3 740 78 199 11 TK ohmse OK 4 2 574 20 97 344 0 1 21389 558110 a SE 0 2 4401 6 38756 Se SE 0 3 2322 4 10788 E it SE SCH Ea SCH 30 179 12 3 453 0 5 1248 2 2665 2 SC 11 2 SE 1 662 43 514 88 a SC 1 4 518 97 251 77 e 10116 0 520 2 413 26 124 05 SE SE S ance 58 036 150 65 864 0 295 4 2 277 32 32 209 200 a 6 234 44 17 816 250 46 664 0 124 10 187 44 28 063 300 41 420 0 088 20 138 79 23 057 350 37 621 0 065 30 4538 AB 400 34 779 0 050 Se EE ES 420 33 839 0 045 50 89 551 0 929 77 35 70 837 0 510 100 61 180 0 358 150 47 782 0 202 200 39 666 0 130 250 34 236 0 090 300
161. oportional gain term generated by autotune This field will be blank until a successful autotune is completed Integral gain term generated by autotune This field will be blank until a successful autotune is completed HD A Control Type Selections are Off Man PID RampP and Table Derivative gain term generated by autotune This field will be B ave amp Exit blank until a successful autotune is completed Table 27 Auto Tune Menu 69 Cryo con Model 24C Front Panel Menu Operation The Options Menu Press the Options key to access the Options Menu This will display the following menu Options Menu Relay 1 Go to the Relay 1 Configuration Menu Relay 2 Go to the Relay 2 Configuration Menu Control Loop 3 Go to the Loop 3 Configuration Menu Control Loop 4 Go to the Loop 4 Configuration Menu The Relay Configuration Menu The Relay Menu is accessed from the Options Menu described above It is used to configure two relay outputs of the Model 24C Relay Configuration Menu Rly Status Status of the Relay Mode Auto Output mode selection Modes are Auto On and Off Source ChA saa the input channel used as the source for controlling the Set point for the High Temperature output The output when High 200 000 enabled will be asserted when the input temperature is above this value Enable Yes High temperature output enable Selections are Yes or No Set point for the Low Temperature output The output
162. or queries the controller s power up in control mode setting Power up in control mode causes the controller to automatically enter control mode 10 seconds after AC power is applied Exercise caution when using this command as it can have unintended consequences SYSTem BAUD 9600 19200 38400 57600 115200 Sets or queries the RS 232 Baud rate SYSTem DATe mm dd yyyy Sets or queries the instrument s date Date is in string format and is surrounded by double quotes Format is mm dd yyyy for month day year SYSTem TIMe hh mm ss Sets or queries the instrument s time Time is in string format and is surrounded by double quotes Format is hh mm ss for hour mm ss Twenty four hour format is used Configuration Commands CONFig lt ix gt NAMe name Instrument setups can be named for user convenience This command sets and queries the user configuration names The parameter lt ix gt is the configuration number which is 0 through 5 The second parameter name is a string with a maximum length of 15 ASCII characters CONFig lt ix gt SAVe Saves an the current instrument setup to a user setup lt ix gt is the index number of the desired instrument setup Values may be 0 through 5 Command only CONFig lt ix gt RESTore Restores a previously stored user instrument setup lt ix gt is the index number of the desired instrument setup Values may be 0 through 5 Command only 122 Cryo con Model 24C Remote Programming Guid
163. or queries the remote LED status indicator on the instrument s front panel Note that the Remote LED is automatically handled by the GPIB interface but must optionally be turned on and off when using the LAN or RS 232 interface SYSTem BEEP lt seconds gt Asserts the audible alarm for a specified number of seconds Command only no query SYSTem DISTc 0 5 1 2 4 8 16 32 64 Set or query the display filter time constant The display filter is time constant filter that is applied to all reported or displayed temperature data Available time constants are 0 5 1 2 4 8 16 32 or 64 Seconds SYSTem ADRS lt address gt Selects the address that the IEEE 488 2 GPIB remote interface will use The address is a numeric value between 1 and 31 with a factory default of 12 The addresses assigned to instruments must be unique on each GPIB bus structure This command has no effect on other interfaces 120 Cryo con Model 24C Remote Programming Guide SYSTem RESeed Re seeds the input channel s averaging filter allowing the reading to settle significantly faster The display filter may have filter time constants that are very long The RESEED command inserts the current instantaneous temperature value into the filter history thereby allowing it to settle rapidly Note The RESEED command is useful in systems where a computer is waiting for a reading to settle Issuing the RESEED command will reduce the required settling time
164. pe rampp Choices are OFF PID MAN TABLE and RAMPP Set the output power level for manual control loop 1 pman 25 Sets the power output of loop 1 to 25 of full scale when the loop is in the manual output mode Read the current output power level loop 2 htrread Reports the current output power as a percentage of full scale 110 Cryo con Model 24C Remote Programming Guide Debugging Tips 1 To view the last command that the instrument received and the last response it generated press the System key and then select the Network Configuration Menu The last two lines of this menu show gt and lt characters These two lines show the last command received by the instrument and the last response generated Some commands require the instrument to write to non volatile flash type memory which can be time consuming In order to avoid overrunning the instrument use compound commands that return a value thus indicating that command processing is complete For example INPUT A UNITS K UNITS will respond with the input units only after the command has completed Another example LOOP 1 SETPOINT 1234 5 OPC Here the operation complete command OPC will return a 1 when command processing is complete It is often easiest to test commands by using the Cryo con utility software Run the program connect to the instrument and use the Interact mode to send commands and view the response Alte
165. point is reached ramping mode terminates and temperature regulation begins at the new setpoint 87 Cryo con Model 24C Basic Setup and Operation Cryocooler Signature Subtraction Cryocoolers often have a thermal signature that is associated with the mechanical cooling process At the low end of their temperature range this signature can have amplitudes of one or more Kelvin Since the thermal signature is related to the mechanical cooling process it is low frequency and has an irregular shape that is rich in harmonics With most coolers the frequency will be a sub multiple of the AC line frequency around 2Hz and the shape will be a narrow spike followed by a long lull If a conventional PID control loop is connected to a cryocooler the thermal signature disrupts the loop and degrades the accuracy of control If a fast PID loop is used it attempts to track the signature which usually results in placing a waveform on the loop output heater that causes control performance to degrade even further In still other systems the thermal signature of the cryocooler is outside of the PID control loop bandwidth enough to cause a phase reversal that actually amplifies the signature causing the entire system to become unstable These systems oscillate with a sine wave at a very low frequency Faced with a significant thermal signature users are generally required to de tune the PID loop and live with the resulting inaccurate control Here th
166. process since the time constants in cryogenic systems are often long Further some systems must operate over a very wide range of temperature requiring different PID settings at different setpoints The following is a guide to various methods of obtaining PID control loop coefficients Various methods for obtaining PID coefficients The system provider If your controller was received as part of a cryogenic system the PID control loops should already be setup for optimum control If the system operates over a wide range of temperature it will use one of the available Table control modes where PID values are listed for different setpoints If the installed PID values do not provide stable control you should contact the system manufacturer for assistance Taking PID values from a different controller If the PID values required to control a system are known from a different type controller these values may be useful The Proportional or P term is a unit less gain factor There is no industry standard definition for it and therefore it can vary significantly from one manufacturer to another If the P term does not work well when used directly try a using the value divided by ten For further assistance please contact Cryo con support The Integral or term is in units of Seconds and should be the same for different controllers Note however that some manufacturers use a Reset value instead of directly using an Integral term In t
167. r gt 465 000000 lt CalCur gt 460 000000 lt CalCur gt 455 000000 lt CalCur gt 450 000000 lt CalCur gt 445 000000 lt CalCur gt 440 000000 lt CalCur gt 435 000000 lt CalCur gt 430 000000 lt CalCur gt 425 000000 lt CalCur gt 420 000000 lt CalCur gt 415 000000 lt CalCur gt 410 000000 lt CalCur gt 405 000000 lt CalCur gt 400 000000 lt CalCur gt 395 000000 lt CalCur gt 390 000000 lt CalCur gt 385 000000 lt CalCur gt 380 000000 lt CalCur gt 375 000000 lt CalCur gt 370 000000 lt CalCur gt 365 000000 lt CalCur gt 360 000000 lt CalCur gt 355 000000 lt CalCur gt 350 000000 lt CalCur gt 172 Cryo con Model 24C Appendix G Sensor Data Tables Appendix G Sensor Data Silicon Diode Silicon diode sensors offer good T K Tables Volts mV K TOE e ios rr Ts i O 4 2 1 75099 49 16 Use in magnetic fields is not 10 1 47130 243 45 recommended 20 1 18867 15 93 Silicon diode sensors use a constant 30 1 10594 3 90 current DC excitation of 10A 50 1 07079 1 47 900 Silicon Dio 77 35 1 02356 1 86 me JO Configu Diode 100 0 98170 1 85 TK volts os 150 0 88365 2 03 1A 1 6396 DP 200 0 77887 2 13 4 2 1 53960 739 91 250 0 67067 2 20 139808 726 04 300 0 55955 2 22 a 148193 SA 355 0 44124 2 10 ap E a 385 0 376
168. racter next to the temperature display indicates that the resistance bridge is not balanced at the proper voltage bias When used with high resistances measurement accuracy steadily degrades due to the extremely low excitation current required The trade off in measurement accuracy vs sensor excitation current is taken for two reasons 1 The sensitivity of NTC resistor sensors is extremely high in the low temperature end of their range Therefore the reduced measurement accuracy does not degrade temperature measurement accuracy 2 The low current settings are required since sensor self heating at low temperature is a very significant source of errors Calibration tables for NTC sensors may be entered either directly in Ohms or in base 10 Log of Ohms to accommodate the generally logarithmic nature of their calibration curves 32 Cryo con Model 24C Specifications Features and Functions CalGen Calibration Curve Generator The CalGen feature generates new calibration curves for Silicon diode or Platinum sensors This provides a method for obtaining higher accuracy temperature measurements without expensive sensor calibrations Curves can be generated from any user selected curve and are written to a specified internal user calibration curve area The CalGen function may be performed in the instrument by using the front panel Alternatively the feature is also implemented in the Cryo con utilities software Input Chann
169. re return is 0 00A LOOP 1 2 3 4 LSENse Queries the control sensed load resistance If the instrument is not controlling temperature return is 1 00 LOOP 1 2 3 4 HTRHst Queries the temperature of the control loop s heat sink Valid for loops 1 and 2 only Returns temperature in C 128 Cryo con Model 24C Remote Programming Guide Control Loop Autotune Commands The Model 24C s control loop autotune functions can be configured and run entirely from the remote interface The general sequence is Configure the autotune parameters Initiate the autotune sequence Read the autotune state and wait for the sequence to complete Execute the autotune save command to transfer the generated tuning parameters to the controller s PID values and continue with PID control PUN A LOOP 1 2 3 4 AUTotune STAR Command to initiate the autotune sequence on the selected control loop LOOP 1 2 3 4 AUTotune EXIT Command to abort the autotune sequence LOOP 1 2 3 4 AUTotune SAVE Command to save the autotune generated PID values to the selected control loop and continue with PID regulation LOOP 1 2 3 4 AUTotune MODe P PI PID Set or query the autotune mode Choices are P to generate P only tuning values PI for Pl values and PID for all values Recommended value is PID LOOP 1 2 3 4 AUTotune DELTap lt num gt Set or query the maximum allowed change in output power that the controller is allowed to generate
170. ress is returned as an ASCII string Cryo con MAC addresses range from 00 50 C2 6F 40 00 to 00 50 C2 6F 4f ff They cannot be changed by the user Mail Commands The Model 24C can send e mail over the Ethernet port when an alarm condition is asserted on an enabled input channel The following remote commands are used to configure e mail However it is much easier to configure e mail using the controller s embedded web server MAIL A B C D ADDR IPA Set or query the e mail server IP address Parameter format is an ASCII string and must be enclosed in quotation marks For example 192 168 0 1 MAIL A B C D FROM from e mail address Set or query the from e mail address Parameter is an ASCII String For example Model24C mynetwork com MAIL A B C D DEST to e mail address Set or query the from e mail address Parameter is an ASCII String For example Model24 mynetwork com MAIL A B C D PORT lt port number gt Set or query the e mail port Parameter is integer and default is 25 MAIL A B C D STATE ON OFF Set or query the input channel e mail send enables If a channel is enabled e mail will be sent when an alarm condition is asserted on the selected input channel 136 Cryo con Model 24C Remote Programming Guide Data Logging Commands DLOG STATe ON OFF Turns the data logging function ON or OFF Equivalent to Start STOP DLOG INTerval lt Seconds gt Sets the data logging time interval in seconds DLOG CO
171. return to the Home Status display 17 Cryo con Model 24C A Quick Start Guide to the User Interface Configuring the Control Loops Before using the Loop 1 main heater control output it is essential that the proper load resistance and output range be selected This is done using the Control Loop Setup menu as follows O Press the Loop 1 key D Use the and 0 keys to select between a 50 Ohm and a 25 Ohm heater and then press the Enter key a Use the navigation keys to scroll to the Range field and then select the desired heater range a Inthe Control Loop Configuration menu Use the up down right and left keys to scroll to the Htr Resistance field An example is shown here Htr Resistance 500 Range HI Be sure to select a range that does not exceed the ratings of your cryostat A summary of full scale output power for the various ranges is given here Max Output Power 25 Watts 50 Watts 2 5 Watts 5 0 Watts 0 25 Watts 0 50 Watts Table 3 Loop 1 Output Summary Next the control type should be set by scrolling to the Type field and selecting the desired loop operating mode Type PID 18 Cryo con Model 24C A Quick Start Guide to the User Interface A summary of control types is given here Control loop is disabled Manual control mode Here a constant heater output power is applied The Pman field selects the output power as a p
172. ring a temperature sensor Configuring an input sensor from the front panel is performed by using the Input Channel Configuration Menu First press input channel key ChA ChB ChC or ChD to select the desired channel for configuration The first line of the Input Channel Configuration menu is used to change the sensor units It shows the selected input channel the current temperature in real time and the current units An 77 123K Sr example is shown here To change the sensor units use the and 0 keys to scroll through the available options When the desired units are shown press the Enter key to make the selection The display will now show the current temperature with the new units Next go to the sensor selection field by pressing the down arrow navigation key This field is used to select the actual sensor type In the example shown below the input channel is currently configured for a standard Cryo con S900 diode sensor Use the and 0 keys to scroll through the available sensors including user sensors When the desired sensor is shown press the Enter key to make the selection A complete listing of selectable sensors is given in Appendix A Sen 1 Cryocon S900 Before one of the user supplied sensors can be used the sensor s calibration curve and configuration data must be installed This is best done by using Cryo con s utility software This completes the process of configuring an input channel Press the Home key to
173. rnatively any communications program like Windows Hyperterminal can be used to interact with the instrument via the LAN or serial ports For ease of software development keywords in all SCPI commands may be shortened The short form of a keyword is the first four characters of the word except if the last character is a vowel If so the truncated form is the first three characters of the word Some examples are inp for input syst for system alar for alarm etc 111 Cryo con Model 24C Remote Programming Guide SCPI Status Registers The Instrument Status Register The Instrument Status Register ISR is queried using the SYSTEM ISR command The ISR is commonly used to generate a service request GPIB when various status conditions occur In this case the ISR is masked with the Instrument Status Enable ISE register The ISR is defined as follows ISR P Bits Bits Bite Bits Bitz Lon Bito _ Where Bit7 Alarm Indicates that an alarm condition is asserted Use the ALARM commands to query individual alarms Bit4 Htr Indicates a heater fault condition Use the HEATER commands to query the heater Bit1 to Bit0 SFx Indicates that a sensor fault condition is asserted on an input channel Use the INPUT commands to query the input channels The Instrument Status Enable Register The Instrument Status Enable ISE Register is a mask register It is logically anded with the contents of the ISR in
174. rom Live Circuits Operating personnel must not remove instrument covers There are no internal user serviceable parts or adjustments Refer instrument service to qualified maintenance personnel Do nat replace components with power cable connected To avoid injuries always disconnect power and discharge circuits before touching them Cleaning Do not submerge instrument Clean exterior only with a damp cloth and mild detergent Grounding To minimize shock hazard the instrument is equipped with a three conductor AC power cable Plug the power cable into an approved three contact electrical outlet only Safety Symbols O Or ede Direct current power line Equipment protected throughout by double insulation or reinforced insulation equivalent to Class II of 1EC536 Alternating current power line Alternating or dirrect current power line Caution High voltages danger of electric shock Background color Yellow Symbol and outline Black Three phase alternating current power line Earth ground terminal Caution or Warning See instrument documentation Background color Yellow Symbol Frame or Chassis terminal and outline Black On AC Power Protective conductor terminal gt gt o h Fuse Off AC Power 39 Cryo con Model 24C Front Panel Operation Front Panel Operation The user interface of the Model 24C Cryogenic Temperature Controller consists of a 40 character by eight
175. rument must be returned to Cryo con for repair or recalibration a Return Material Authorization RMA number must first be obtained from the factory This may be done by Telephone FAX or e mail When requesting an RMA please provide the following information 1 Instrument model and serial number 2 User contact information 3 Return shipping address 4 Ifthe return is for service please provide a description of the malfunction If possible the original packing material should be retained for reshipment If not available consult factory for packing assistance Cryo con s shipping address is Cryogenic Control Systems Inc 17279 La Brisa Rancho Santa Fe CA 92067 7012 13 Cryo con Model 24C Preparing the controller for use Instrument Accessories Cryo con Part Description pun ooo MECO enano Table 1 Model 24C Instrument Accessories 14 Cryo con Model 24C Preparing the controller for use Cryogenic Accessories 900 series Silicon diode Temperature Sensors Temperature range 1 4 to 500K Cryo con R400 Ruthenium Oxide temperature sensor R400 Temperature range 2 0K to 273K Optimized for use in Liquid Helium systems including superconducting magnets Cryo con R500 Ultra low temperature Ruthenium Oxide temperature sensor Temperature range lt 100mK to 40K CP 100 CP 100 series Ceramic Wound RTD 1000 GP 100 series Glass Wound RTD 100Q XP 100 XP 100 series Thin Film Platinum RTD 100Q
176. rument s 1A Sample Holder 2B First Stage configuration menus 251 445k 123 845k requires only the press of 300 000K_1 Off Low 100 000K 2 Off Low a single key As always ii SES Te convenient names can be 15 445k 4 845k RO 600 RuOx 10mV R500 RuOx 1 0mV assigned to input channels Cryo con Model 24C Introduction Cryo con s innovative instrument configuration menus show real time status information so the user can instantly view the results of any changes made On the control loop menu Loop 1A Sample Holder the controlling source Set Pt 300 000K A 123 456K _ temperature heater range rosin oe ane Ramp 42 ot Mig and power output level can Dgain 7 500 S Range MID be observed while tunina a Pman 5 0000 PID Table index 2 H Type RampT Htr Load 500 loop Input ChA Next2 An essential feature for debugging system software is the Network nfiguration Network Configuration Menu 7 el i GE gurauo Dev M24C1234 00 50 C2 6F 40 3C enu s ability to show DHCP Ena On IP 192 168 0 198 remote commands as they Msk 255 255 255 0 GWy 192 168 0 1 are sent and received to the instrument gt input a temp units name sys time lt 0 5321 K Sample Holder 14 37 25 Sensor Curves The Model 24C includes built in curves that support most industry standard temperature sensors Additionally eight user calibration curves are available for custom or calibrated sensors Each user curve may have up to 200 entries and are entered
177. ruments Inc RO 105 Ruthenium Oxide sensor SI RO 105 Temperature range is 2 to 273K Use with the NTC10uA input configuration only Scientific Instruments Inc RO 600 Ruthenium Oxide sensor with SI RO 600 constant voltage AC excitation Temperature range is lt 50mK to 40K Use 1 0mV bias Cryocon R500 Ruthenium Oxide Sensor with constant voltage AC excitation Temperature range is lt 50mK to 40K Use 1 0mV bias ec ec O TC AuFe 07 Chromel AuFe 7 thermocouple Range 3 to 610K Internal reference temperature 141 Cryo con Model 24C Appendix A Installed Sensor Curves The SENSORIX remote commands are used to query and edit sensors installed in the controller For example the command INPUT B SENSORIX 34 would set input B to use the R400 sensor INPUT A SENSORIX 1 would set input A to use the S900 diode INPUT A SENSORIX 0 would turn input A off by setting the sensor to none SENSORIX 1 NAME Returns the name string at index 1 Factory installed sensors may not be edited by using these commands User Installed Sensor Curves The user may install up to four custom sensors This table shows the sensor index and default name of the user curves User Curve Sensor IX Default Name ACI f a A a ss tse sensors Ps 06 User Sensor Ps o _User Sensor Pp 7 68 User Sensors Using the above table the SENSORIX commands can be used to address the user curves For example INPUT B SENSorix 62
178. s 1 2 SOURce A B C D RELays 1 2 MODe auto control on off RELays 1 2 HIGHest lt setpt gt RELays 1 2 LOWEST lt setpt gt RELays 1 2 DEADband lt deadband gt RELays 1 2 HIENa YES NO RELays 1 2 LOENa YES NO PIDTable lt num gt PIDTable lt num gt NAMe Name String PIDTable lt num gt NENTry PIDTable lt num gt PIDTable lt num gt TABLe 117 Cryo con Model 24C Remote Programming Guide NETWork IPADdress NETWork PORT lt port number gt NETWork MACaddress NETWork NAMe Name NETWork DHCP ON OFF MAIL A B C D ADDR IPA MAIL A B C D FROM from e mail address MAIL A B C D DEST to e mail address MAIL A B C D PORT sport number gt MAIL A B C D STATE ON OFF CLS ESE ESR OPC IDN RST SRE STB DLOG STATe ON OFF DLOG INTerval lt Seconds gt DLOG COUNt DLOG DLOG READ DLOG RESEt DLOG CLEAr 118 Cryo con Model 24C Remote Programming Guide Remote Command Descriptions IEEE Common Commands CLS The CLS common command clears the status data structures including the device error queue and the MAV Message Available bit ESE The ESE command sets the Standard Event Status Enable ESE Register bits The ESE Register contains a bit mask for the bits to be enabled in the Standard Event Status SEV Register A one in the ES
179. s are asserted or cleared based on the temperature reading of selected input channels Each output has a high and low set point that may be enabled from the front panel or a remote interface Furthermore relays can be manually asserted ON or OFF Normally Open contacts are available on the rear panel Contact rating is 10A 125 VAC 5A 0250 VAC or 5A 030 VDC for resistive loads Maximum switching power is 150W Remote Interfaces Ethernet LAN and RS 232 interfaces are standard IEEE 488 2 GPIB and USB are external field installable options All functions and read outs available from the instrument may be completely controlled by any of these interfaces The LAN interface is electrically isolated and is 10 100 BaseT compliant Connection is made via the RJ 45 connector on the rear panel The Serial port is an RS 232 standard null modem with male DB9 connector Rates are 9600 19 200 and 38 400 Baud When installed the GPIB option is fully IEEE 488 2 compliant Connection is made at the rear panel s LAN port The programming language used by the Model 24C is identical for all interfaces and is SCPI language compliant 36 Cryo con Model 24C Specifications Features and Functions Rear Panel Cryogenic Control Systems Inc Model 24C Temperature Controller 100 240VAC 50 60Hz 175W Max V Figure 3 Model 24C Rear Panel Layout AC Power Connection The Model 24C requires single phase AC power of 50 to 60 Hz Voltag
180. s available Calibration is Closed Case There are no internal mechanical adjustments required The Model 24C cannot be calibrated from the front panel Calibration data is stored in the instrument s non volatile memory and is accessed only via the remote interfaces A calibration procedure document may be obtained by contacting Cryo con technical support at CCTechSupport cryocon com Cryo con Calibration Services When the controller is due for calibration contact Cryo con for low cost recalibration The Model 24C is supported on our automated calibration systems which allow Cryo con to provide this service at competitive prices Calibration Interval The Model 24C should be calibrated at a regular interval determined by the measurement accuracy requirements of your application A 90 day interval is recommended for the most demanding applications while a 1 year or 2 year interval may be adequate for less demanding applications Cryo con does not recommend extending calibration intervals beyond 2 years Whatever calibration interval is selected Cryo con recommends that complete re adjustment should always be performed at the calibration interval This will increase user confidence that the instrument will remain within specification for the next calibration interval This criterion for re adjustment provides the best measure of the instrument s long term stability Performance data measured using this method can easily be used to
181. s ground Common Installation Issues Cold Junction Compensation Cold Junction Compensation in the Cryo con thermocouple module is performed by a circuit that measures the temperature of the input connector pins This reading is then used offset the device s output voltage Errors can be minimized by reducing local air currents around the module 97 Cryo con Model 24C Basic Setup and Operation Device Calibration Errors Variation in the manufacture of thermocouple wire and it s annealing over time can cause errors in temperature measurement Instruments that measure temperatures above about 0 C will usually allow the user to correct calibration errors by adjusting an offset in order to zero the error at room temperature Unfortunately in cryogenic applications thermocouples lose sensitivity at low temperatures so a single offset voltage correction is insufficient Thermocouples used over a wide temperature range may need to be calibrated at two temperature extremes AC Power Line Noise Pickup AC power noise pickup is indicated by temperature measurements that are significantly in error In extreme cases there may be no valid measurements at all When a grounded sensor is used a poor quality ground may have sufficient AC voltage to exceed the input range of the module This can often be corrected by running a copper connection from a point near the sensor ground and the chassis ground of the controller Defective building wiring or in
182. s will not result in a glitch in heater output power 2 Once aramp mode is selected ramping is performed as above by changing the setpoint The current status of the ramp function may be seen on the Operate Screen When a ramp is active the word RMP will appear in the control loop status displays It may also be queried via any of the remote ports using the LOOP 1 RAMP Command 85 Cryo con Model 24C Basic Setup and Operation Ramping Algorithm The ramp algorithm uses a basic PID type control loop and continuously varies the setpoint until the specified temperature is reached This means that the PID control loop will continuously track the moving setpoint The result is that there will be small time lag between the target ramp and the actual temperature Although not normally a problem the ramp time lag may be minimized by using aggressive PID values This is accomplished by increasing P decreasing and setting D to zero Ramping Parameters and Setup The Ramp Rate is set on the Control Loop Setup menu Note that the ramp rate on Loop 1 is independent of the rate on Loop 2 Ramping Example First the controller must have PID tuning values that give stable temperature control at both the beginning and end of the ramp The PID values are usually slow Low values for P high for and zero for D The actual values are not critical they just need to give stable control Next set the control type to RampP and s
183. sing an external power booster ooococcconncocccccccccocccnncononncnncnnnnn nn cannnn 91 USING Cal DEE 91 Using Thermocouple Gensors cnn nnncnnnnnnn 95 System Shielding and Grounding Lesues rrr rnrrerrreeea 99 Instrument Calbratton 101 Cryo con Calibration Gervices reeeerr teeren nenene 101 Calibration Internal 101 Remote e le EE 102 Remote Interface Confouratton 102 Cryo con Model 24C Remote Programming Guide 105 General COverview 105 An Introduction to the SCPI Language 106 Remote Command Tree 115 Remote Command Descriptions ccceeeeeeeeeeeeeeeeeceteeeeeeeeeeeeaeees 119 Code snippet in tico e ege ENNEN 138 EU Declaration of Confort 139 Appendix A Installed Sensor Curves ceeceececeeeeeeeeeeeeeeeeeteeeeeeees 141 Factory Installed Curves A 141 User Installed Sensor Cupmves 142 Sensor Curves On CD 143 User Calibration Curve File Fommat 143 Appendix B Updating Instrument Firmware 147 RI Ee DEE 147 Updating unit frmmware cc 148 Appendix C Troubleshooting Guide 151 Eror Displays ca a A c 151 Control Loop and Heater Droblems ne 152 Temperature Measurement Errors ccccccccceeeeeeeeeeeeeeeeeeeaneeeeeees 153 Remote I O problems ennnen 154 General Problems veia cesses entender unis cede idee deve 156 Appendix D Tuning Control Loops rnrn ne 157 lge lee EE 157 Various methods for obtaining PID coeftclents cee 157 Manual Tuning Procedures 158 Appendix
184. sistance field is an enumeration that sets the value of the heater load resistance Choices are 50Q and 250 When 500 is selected the heater will output a maximum of 50 Volts at 1 0 Ampere or 50 Watts When 25 Ohms is selected the maximum heater voltage is 25 Volts and the output power is 25 Watts For additional information please refer to the Loop 1 Heater output ranges or the Loop 2 Output Ranges tables Warning It is necessary to set the Load resistance field to the actual value of the heater load resistance being used If an incorrect value is selected output power indications will be incorrect non linear heater operation may result If the actual heater resistance is less than selected the heater may overheat resulting in an automatic over temperature shutdown Ramping Rate Numeric entry Default 0 10 min When performing a temperature ramp the Ramp field defines the ramp rate Units are display units per minute In the default case this means Kelvin per minute For more information on temperature ramps refer to the section on Temperature Ramping 58 Cryo con Model 24C Front Panel Menu Operation User Configurations Menu The User Configurations Menu is displayed by pressing the Config key It is used to save or restore up to four instrument setups Each setup saves the entire state of the Model 24C including setpoints heater configurations input channel data etc User Configurations Menu Pressing the En
185. so be inexpensive and easy to install However devices used in cryogenic applications are often difficult to apply because they exhibit poor sensitivity at low temperature and are generally constructed with metals that are difficult to use In order to obtain the best possible measurement accuracy the recommendations given here should be carefully applied Installing the Thermocouple Module All thermocouple sensors require the use of an optional Cryo con external thermocouple module 4039 004 This module plugs into any sensor input channel of a Model 24C Up to four modules can be installed on a single instrument and they can easily be added or removed at any time They are powered by the Model 24C and perform amplification cold junction compensation open sensor detection and connection to copper Internal switches are used to select the cold junction compensation for specific types Open the module and use the switches to select types K E T AuFe 0 7 or off Figure 5 Thermocouple Module Module Configuration Before a thermocouple module can be used the thermocouple type must be set into the module s internal switches This selects the cold junction compensation method To access the switches remove the cover by removing the two screws from the plastic cover The type is set by the four switches shown here Settings are E Kor T AuFe 0 7 and OFF The Off setting disables cold junction compensation Select the type by sliding
186. ssary to insert a blank space to separate a parameter from a command keyword Compound Commands A semicolon is used as a separator character that separates commands within the same subsystem For example sending the following command string INPut A UNITs K TEMPer has the same effect as sending the following two commands INPut A UNITs K INPut A TEMPer If multiple commands address different subsystems the combination of a semicolon and a colon are used The semi colon terminates the previous command and the colon indicates that the next command is in a different subsystem For example INPut A TEMPer LOOP 1 SETPt 123 45 has the effect of sending the following two commands INPut A TEMPer LOOP 1 SETPt 123 45 Queries You can query the current value of most parameters by adding a question mark to the command For example the following command set the setpoint on control loop 1 to 123 45 LOOP 1 SETPt 123 45 You can change it into a query that reads the setpoint by using the following LOOP 1 SETPt The instrument s response will be a numeric string such as 123 45 Compound queries are commonly used to save programming steps For example the query LOOP 1 SETPt PGAin IGAin DGAin reports the loop 1 setpoint P gain Loan and D gain An example response is 123 45 20 0 60 12 5 Note that the response is also separated by semicolons The representation of the decimal symbol for floating point numbers mu
187. st be a period instead of comma as is customary used in some European countries Command Terminators Each command must be terminated with a line feed An character SCPI Common Commands The IEEE 488 2 SCPI standard defines a set of common commands that perform basic functions like reset self test and status reporting Note that they are called common commands because they must be common to all SCPI compliant instruments not because they are commonly used 107 Cryo con Model 24C Remote Programming Guide Common commands always begin with an asterisk are four to five characters in length and may include one or more parameters Examples are IDN CLS OPC SCPI Parameter Types The SCPI language defines several different data formats to be used in program messages and response messages Numeric Parameters Commands that require numeric parameters will accept all commonly used decimal representations of numbers including optional signs decimal points and scientific notation Enumeration Parameters These are used to set values that have a limited number of choices Query responses will always return an enumeration parameter in upper case letters Some examples of commands with enumeration parameters are INPut A B C D UNITsS K C F S LOOP 1 2 TYPe OFF MAN PID TABLE RAMPP String Parameters String parameters can be up to 15 characters in length and contain any ASCII characters ex
188. store configurations for various experiments XML Extensible Markup Language is used for the structure and format of script files XML can be generated and edited with a standard text editor Further it is easy to read and understand Firmware updates Instrument firmware updates may be installed by using the Ethernet connection Cryo con provides firmware updates on request via e mail They are free of charge and generally include enhancements and new features as well as problem fixes Send e mail to cctechsupport cryocon com Ethernet API An Applications Program Interface API package is supplied that facilitates communication with the instrument using the TCP IP and UDP protocols It is supplied as a Microsoft Windows DLL that is easily linked with C C or Basic programs Cryo con Model 24C Preparing the controller for use Preparing the controller for use The following steps help you verify that the controller is ready for use Supplied Items Confirm that you have received the following items with your controller If anything is missing contact Cryogenic Control Systems Inc directly a Model 24C Cryogenic Temperature Controller D This User s Manual a Cryo con software CD Q Input connector kit 4024 016 consisting of four screw in DIN 6 input connectors PN 04 0414 a Output connector kit 4124 018 consisting of a 10 pin detachable terminal block 04 0007 and a dual banana plug 04 0433 D Detachable 1
189. sufficient grounding is usually the root cause General recommendations to minimize AC pickup include 1 Minimize the length of the thermocouple wires Connect the module as near as possible to the sensor so that thermocouple wires are converted to copper as soon as possible 2 Twist the wires 3 Avoid running sensor wires near or parallel to AC power lines 98 Cryo con Model 24C System Shielding and Grounding Issues System Shielding and Grounding Issues The Model 24C supports a single point grounding scheme to prevent ground loops and low frequency power line noise pickup A single point ground scheme starts with the establishment of a good quality ground point somewhere in your system All components of the system including the cryostat and connected instruments should have a direct low impedance connection to this point In many systems the ground point can be the third wire ground connection of the AC power outlet If your facility does not provide a good quality ground in it s AC power distribution scheme it is strongly recommended that one be fabricated Noise pickup and ground loop problems are usually traced to how this connection is made To minimize RFI noise pickup The Model 24C implements a shielding scheme that allows the construction of a complete shield around the instrument and cryostat The instrument s enclosure is all Aluminum with wide conductive overlaps on all mating surfaces Connecting cable shiel
190. t calibration procedure described in the section titled Using Thermocouple Sensors No temperature reading Review the Error Displays section above Remote UO problems Symptom Condition Can t talk to RS 232 Possible causes interface 1 Ensure that the RS 232 port is selected Press the System key and scroll down to the RIO Port field Ensure that the baud rate of the controller matches that of the host computer To check the controller s baud rate press the System key and scroll down to the RIO RS232 field Ensure that the host computer settings are 8 bits No parity one stop bit The RS 232 port does not have an effective hardware handshake method Therefore terminator characters must be used on all strings sent to the controller Review the RS 232 Configuration section Ensure that you are using a Null Modem type cable There are many variations of RS 232 cables and only the Null Modem cable will work with Cryo con controllers This cable is detailed in the RS 232 Connections section Debugging tip Cryo con utility software can be used to talk to the controller over the RS 232 port using the terminal mode All command and response strings are displayed This is a good way to establish a connection Intermittent lockup on RS Possible causes 232 interface Long cables Try using a lower baud rate In some cases inserting a 50mS delay between commands will help Noise pickup Try using shielded cables
191. te This section applies only to the internal data logging feature of the Model 24C Remote data logging is also supported by the Cryo con Utility Software program The Data Logging Configuration menu is used to start stop and configure the data logging process This menu is accessed from the System Menu The only user configurable y 9 DataLogging Configuration Menu parameter is the Interval in State ON units of seconds Once this Interval 5 Sec Count 562 is set data logging starts Last Log 8 1 2010 13 15 09 when the State is ON and Press Enter to delete data log buffer stops when the state is OFF The last line of the field can be used to clear the buffer The data logging function records all four input temperatures along with a real time clock stamp The log buffer is circular and contains 1365 entries Then the maximum number of entries is exceeded the oldest samples are written over The buffer is maintained in Non Volatile memory and will therefore survive a power failure DataLogging Configuration Menu HState ON Sets the Data Logging interval in units of Interval 5 Sec Seconds Minimum is 1 and maximum is 99 999 Count 1365 Last Log 8 1 2010 12 59 50 Press Enter to delete data log buffer Logged data is read via any of the remote interfaces as follows Hyperterminal Enter the command DLOG Note you should setup a Receive File to store the data before executing this command because a l
192. te spaces Floating point numbers may be entered with many significant digits They will be converted to 32 bit floating point which supports about six significant digits The last entry of a table is indicated by a semicolon character with no characters on the line O NOTE All curves must have a minimum of two entries and a maximum of 200 entries Entries may be sent to the instrument in any order The instrument will sort the curve in ascending order of sensor reading before it is copied to Flash RAM Entries containing invalid numeric fields are deleted before the curve is stored 144 Cryo con Model 24C Appendix A Installed Sensor Curves The following is an example of a calibration curve transmitted to the instrument via the LAN interface Good Diode Diode 1 0 volts 0 34295 300 1205 0 32042 273 1512 0 35832 315 0000 1 20000 3 150231 1 05150 8 162345 0 53234 460 1436 In summary 1 Lines must always be terminated by a line feed character n Carriage return characters r are ignored The first line is a name string that can be up to 15 characters Longer strings are truncated by the instrument The second line identifies the instrument s input configuration and must be one of the allowed selections described in the Supported Sensor Configurations section The third line is the multiplier field and is 1 0 for PTC sensors and 1 0 for NTC sensors or diodes The fourth line of the header
193. te command The name is used by LAN systems that have name servers In this case the instrument can be addressed by it s name rather than its IP address The IP address uniquely identifies the instrument on the LAN The factory default is 192 168 1 5 While any address can be entered addresses usually begin with 192 168 which is a Class C network Other addresses are used only when the instrument is directly connected to the Internet The subnet mask is used to divide the LAN addresses into segments The default subnet mask is 255 255 255 0 A gateway IP address need only be entered if the instrument communicates with the Internet via a gateway The factory default gateway is 192 168 0 1 which is used in systems with Internet Connection Sharing 64 Cryo con Model 24C Front Panel Menu Operation PID Tables Menu The Model 24C can store six user generated PID tables Each table may have up to sixteen setpoint zones Each setpoint zone in a table requires the entry of a setpoint along with corresponding values for P D and full scale heater range When controlling in the Table mode the Model 24C will derive control loop PID coefficients and heater range by interpolation of the PID Table zones based on that zone s setpoint PID Tables can be used with both control loops Building a table from the front panel requires the entry of several numeric values For this reason the user may want to consider using one of the remote interfac
194. temperature field Calibration Curve Menu Sets the current index to an entry within the current table Values are HIX 123 0 to 159 When the Enter key is pressed the following lines will display any data corresponding to the selected entry HT 232 0050 Temperature Units are always in Kelvin E Sensor reading Units are taken from the Sensor Setup menu AS 1 00002 described above and may be Volts Ohms or Logohms Pressing Enter save entered data and exit the menu To exit without 8SaveCurve amp Exit saving press the Home key Table 26 Calibration Curve Menu 68 Cryo con Model 24C Front Panel Menu Operation The Auto Tune Menu The Model 24C can automatically tune both control loops For a complete description of the autotune process including configuration of the tuning menus refer to the section titled autotuning The autotuning menu entries are shown below Auto Tune Menu 2 Sets the loop number for autotuning Each control loop must be Autotune Loop 1 tuned separately Sets the maximum power delta allowed during the tuning DeltaP 5 process Value is a percent of full scale output power for the selected loop Mode PI Sets autotuning mode Choices are P PI or PID P E Sets the autotune timeout in seconds If the process model has Timeout 1805 not converged within this time tuning is aborted Pressing Enter will initiate the autotune sequence The current Bidle Go auto tune state is also shown Pr
195. ter is used to subtract synchronous noise from the input channel An example of synchronous noise is the thermal signature of a cryocooler The default value of 7 taps is used for a line frequency synchronous cryocooler Values go from 1 off to 25 taps with 25 corresponding to 2 5 seconds of filtering This is an advanced setup function Unless you are familiar with the synchronous noise source that you are trying to remove leave this field at its default value of 7 When the number of taps is changed the control loops will have to be re tuned because this filter affects the PID values AC Line Frequency Selection Enumeration Default 60Hz Select the AC power line frequency Choices are 50 or 60 Hz This function only affects the operation of the Synchronous Filter described above 61 Cryo con Model 24C Front Panel Menu Operation Power up in Control Mode Default Off The Auto Ctl field sets the power up mode of the controller s loops Choose Off for normal operation where the control loops are engaged by pressing the Control key and disengaged by pressing the Stop key When on the controller will power up then after ten seconds will automatically engage the control loops Caution When enabled the Power Up in Control mode feature causes the controller to engage the control loops automatically whenever AC power is applied Please exercise caution in the use of this feature Over Temperature Disconnect Configuration N
196. ter key saves the instrument setup to BSave the selected configuration number 2 Recall Pressing the Enter key restores a saved configuration Table 20 User Configurations Menu Saving a User Configuration In the Config menu navigate to the Save field of the desired configuration Press the Enter key to execute the save Restoring a User Configuration First press the Config key and navigate to the Recall field of the desired configuration Press the Enter key to execute the restore 59 Cryo con Model 24C Front Panel Menu Operation The System Configuration Menu This menu is accessed by pressing the System key from the Home Status Display It is used to set many of the instrument s parameters j j System Configuration Menu including display resolution Display TC as FW Rev 1 00A I O port settings etc Display Res 3 Network Config Pwr Up In Cl No RS232 9600 AC Line 60Hz GPIB Adrs 12 Datalog Config Date 08 01 2009 Over Temp Config Time 12 12 42 System Configuration Menu S Sets the display time constant in seconds Selections 1 Display TC 45 range from 0 5S to 64S Display Res 3 Sets the resolution Selections are 1 2 3 or Full Network Config Press Enter to go to the network configuration menu RS232 9600 Sets RS 232 port baud rate GPIB Adrs CC UO address Note GPIB is an external N S a 8Datalog Config Press Enter to go to the data logging setup screen 3 Press
197. terfaces are electrically isolated to prevent ground loops Ethernet Supported protocols include HTTP TCP IP UDP and SMTP Electrically isolated RS 232 Serial port is an RS 232 standard null modem Rates are 9600 19 200 38 400 557 600 and 115 200 Baud IEEE 488 GPIB External option Full IEEE 488 2 compliant USB 2 0 External option Serial port emulator Language Remote interface language is IEEE 488 2 SCPI compliant Further it is identical within the entire Cryo con instrument line Compatibility National Instruments LabView drivers available for all interfaces Ethernet API available for C and Basic User Setups Four User Setups are available that save and restore the complete configuration of the instrument General Ambient Temperature 25 C 5 C for specified accuracy Mechanical 8 5 W x 3 5 H x 12 D One half width 2U rack Instrument bail standard rack mount kit optional Weight 9 Lbs Enclosure Aluminum Machined Aluminum front panel Power Requirement 100 120 220 or 240VAC 5 10 50 or 60Hz 150VA max 26 Cryo con Model 24C Specifications Features and Functions Performance Summary Measurement Accuracy Diode Sensors The formulas for computing measurement accuracy while using diode sensors are 6 5 MAV 60 10 510 SenRdg MAV MAT SenSen Where MAV is the electronic Measurement Accuracy in Volts MAT is the Measurement Accuracy in Kelvin SenRdg is the s
198. the input channel that is used as the source for the Over Temperature Disconnect feature OVERtemp TEMPerature lt temp gt Sets and queries the temperature used by the over temperature disconnect feature Note that this temperature has the same units of the source input channel 130 Cryo con Model 24C Remote Programming Guide Relay Commands The relay subsystem includes the two auxiliary relays in the Model 24C Using the RELAYS commands these relays are independently configured to assert or clear based on the status of any of the four sensor input channels Relay outputs are dry contact and are available on the rear panel of the instrument The user selectable display time constant filter is applied to input channel temperature data before relay conditions are tested The user selectable relay deadband is also applied RELays 1 2 Relay Status Query The two auxiliary relays available in the Model 24C are addressed as 0 and 1 The RELAYS command can be used to query the status of each relay where Relay is in Auto mode and is clear Hi Relay is asserted by a high temperature condition Lo Relay is asserted by a low temperature condition ON Relay is in manual mode and is asserted OFF Relay is in manual mode and is clear RELays 1 2 SOURce A B C D Relay Input Source Sets or queries the source input channel for a specified relay RELays 1 2 HIGHest lt setpt gt Relay High setpoint Sets or queries the
199. the user can change the setpoint while still viewing the temperature of the controlling source channel This allows the user to view the temperature without leaving the setup menu Note Entry of a setpoint can be overridden by the Maximum Setpoint field described below The instrument will not accept an entry that exceeds the maximum Control loop setpoints may also be entered by using the Set Pt key Control Loop PID values Numeric Entry The Pgain Igain and Dgain lines correspond to the Proportional Integral and Derivative coefficients of the control loop Pman is the output power that will be applied to the load if the manual control mode is selected Values for the Proportional or P gain term range from zero to 1000 This is a unit less gain term that is applied to the control loop Gain is scaled to reflect the actual heater range and the load resistance 55 Cryo con Model 24C Front Panel Menu Operation Integrator gain values range from zero to 10 000 The units of this term are Seconds A value of zero turns the integration function off Derivative gain values have units of inverse Seconds and may have values from zero to 1000 A value of zero turns the Derivative control function off The Pman field is only used when the heater output is in manual control mode The value is represented in percent of full scale output power Watts and may have values from zero to 100 Note The Model 24C expresses
200. to the Home Operate Display Proportional gain term generated by autotune This field will be blank until a successful autotune is completed Table 31 Autotune Menu The Delta P field is in percent and is the maximum change in output power that the controller is allowed to apply during the modeling process A value of 100 allows use of full scale power increments A value of 20 uses a maximum power increment of 20 of the current heater output The Mode field tells autotune to generate coefficients for P only PI only or PID Choices are P PI and PID The Timeout field is in units of Seconds and indicates the maximum period of time that the process model will run before aborting This value should be set to at least two or three times the estimated maximum time constant of the process Note Depending on the setup configuration the autotune algorithm may apply full scale heater power to the process for an extended time Therefore care should be taken to ensure that autotune does not overheat user equipment If overheating is a concern the Over Temperature Disconnect Monitor should be configured to disconnect the heater and abort the autotune process when an input temperature exceeds the specified maximum 83 Cryo con Model 24C Basic Setup and Operation The autotune sequence is initiated by selecting the Go field If the initialization of process modeling is successful the status display line will cha
201. tpoint This is useful where a process must operate over a wide range temperature range since optimum PID values usually change with temperature To use the Table mode effectively the user must first characterize the cryogenic process over the range of temperature that will be used then generate PID and heater range values for various temperature zones This is usually done using the autotune capability Once the information is placed into a PID Table the Model 24C will control in Table mode by interpolating optimum PID values based on setpoint The Model 24C allows for the entry of six independent PID Tables Each table may contain up to 16 temperature zones In the Ramp control mode the controller approaches a new setpoint at a user specified rate When this setpoint is reached the controller will revert to PID control 35 Cryo con Model 24C Specifications Features and Functions Alarm Outputs Alarm outputs include a LED indicator an audible alarm on screen display and remote reporting Alarms may be asserted based on high temperature low temperature input sensor fault or heater fault conditions A user selectable dead band is applied to all alarms The High and Low temperature alarms may be latched See the Input Channel Configuration Menu O Note To clear a latched alarm first press the Alarm key and then press the Home key Relays The Model 24C has two dry contact mechanical relay outputs Relay
202. tually any cryogenic temperature sensor produced by any manufacturer The four output control loop circuits feature a primary 50W heater a secondary heater of 25W and two 10 Volt non powered outputs All control modes are supported by all outputs The 24C front panel incorporates a large high resolution graphics TFT type Liquid Crystal Display with an exceptionally wide viewing angle With it s bright white LED back light complete instrument status can be seen at a glance even from across the room Sensor Inputs The Model 24C has four identical input channels each of which implements a ratiometric AC resistance bridge This bridge uses separate balanced circuits to simultaneously measure both the voltage drop across the temperature sensor and the current flowing through it By measuring current with a higher accuracy than it can be set precision resistance measurements are obtained even at low excitation levels Negative Temperature Coefficient NTC resistors are often used as low temperature thermometers especially at ultra low temperature Examples include Ruthenium oxide Carbon Glass Cernox Carbon Ceramic Germanium and several others Their resistance and sensitivity increase dramatically at low temperature but their sensitivity is usually poor at warmer temperatures The Model 24C provides robust support for NTC resistor sensors by using constant voltage AC excitation In the warm region where the sensor has low resistance
203. ure that monitors a selected input and will disconnect both control loops if the specified temperature is exceeded This feature should be enabled in order to protect your equipment from being over heated To enable press the System key and refer to the System Functions Menu section O NOTE Factory defaults may be restored at any time by use of the following sequence 1 Turn AC power OFF 2 Press and hold the Enter key while turning power back ON This sequence will restore factory defaults including resetting user supplied sensor calibration curves and saved user configurations However it will NOT erase the instrument s internal calibration data 11 Cryo con Model 24C Preparing the controller for use Model Identification The model number of all Cryo con controllers is identified on the front and rear panel of the instrument as well as in various instrument displays Ordering Information Model 24C Controller with four standard multi function sensor input channels Controller includes User s Manual Cryo con software CD four input connectors heater connector terminal block plug detachable power cord and a certificate of calibration Specify AC Line Voltage when ordering 100 Configured for 90 100VAC with detachable USA power cord 110 Configured for 110 120VAC with detachable USA power cord 220 Configured for 220VAC with detachable universal Euro Shuko line cord 240 Configured for 240VAC
204. urement Drift 25ppm C Input Range 70mV Accuracy 1 0u V 0 05 Resolution 0 0003 Installed Types K E T and Chromel AuFe 0 07 Input Connector Isothermal Screw type terminals NTC Resistor Sensors Type Constant Voltage AC resistance bridge with excitations of 10mV 3 0mV 1 0mV and 300u4V RMS Fixed or auto ranged Excitation Current 2 5mA to 10nA Four ranges of 2 5mA 250uA and 25uA full scale Excitation Frequency 7 5Hz bipolar square wave Drift gt 10Q and lt 10KQ 15ppm C lt 10Q or gt 10KQ 25ppm C over an ambient temperature range of 25 C 5 C DC Offset Current lt 8nA by active cancellation Resistance Range 0 50 to 1 0MQ Resistance 10mV 3 0mV 1 0mV 300uV Maximum 1 0MQ 100KQ 100KQ 33KQ Minimum 10 0 50 0 50 0 160 Table 7 Minimum and Maximum Resistance vs Bias Voltage 23 Cryo con Model 24C Specifications Features and Functions Resolution Shown below are typical RMS resistance noise values measured at 50 of full scale on a room temperature resistor with a 3 Second analog time constant 400 1 0mA 1 0mA 1004A 25510 25510 2 6m0 ee Ji fon oe EE wa o a Table 8 Resolution for NTC Resistors Accuracy Accuracy for the 10mV bias setting is specified in ranges according to the following table The formulas apply from the maximum to the minimum resistance shown below 10
205. urrent source Maximum compliance is selectable at 25V or 50V Ranges Three output ranges of 1 0A 0 33A and 0 10A full scale which correspond to 50W 5 0W and 0 5W when used with a 50Q load Load Resistance 250 or 50Q for maximum output Minimum Load 100 in 25Q setting 409 in 504 setting Digital Resolution 1 0PPM of full scale corresponding to 20 bits Readback Heater output power Heatsink temperature Connector Dual Banana plug Loop 2 Heater Output Type Short circuit protected linear current source Compliance is 36V Ranges 25W or 2 5W full scale into a 50Q load Load Resistance 50Q for maximum output Digital Resolution 1 0PPM of full scale corresponding to 20 bits Readback Heater output power Connector 10 pin detachable terminal block Status Outputs Audible and Visual Alarms Independent audible and visual alarms Status reported via Remote Interface Heater over temperature fault Loop 3 and 4 Outputs Type 0 10 or 0 5 Volt analog output All control modes available Maximum Output Current 20mA Connector 10 pin detachable terminal block 25 Cryo con Model 24C Specifications Features and Functions Relay Outputs Number 2 Type Dry contact Contact Rating 10A 0125 VAC 5A 09250 VAC or 5A 030 VDC for resistive loads Function Asserted or cleared based on temperature setpoint data Deadband User defined Connector 10 pin detachable terminal block Remote Interfaces Remote in
206. ustry standard sensors plus eight user curves with up to 200 entries each Interpolation is performed using a Cubic Spline CalGen Calibration curve generator fits any diode or resistor sensor curve at 1 2 or 3 user specified temperature points Sensor Performance Specifications Diode Sensors Configuration Constant Current mode 10uA 0 05 DC excitation Note Current source error has negligible effect on measurement accuracy Input voltage range 0 to 2 00VDC Accuracy 80uV 0 005 reading Resolution 2 3uV Drift 25ppm C over an ambient temperature range of 25 C 5 C PTC Resistor Sensors Configuration Constant Current AC resistance bridge mode Ratiometric measurement cancels any error in excitation current Drift 20ppm C over an ambient temperature range of 25 C 5 C AC Excitation Frequency 7 5Hz bipolar square wave Max Min Excitation Bange Resistance Current Resolution Accuracy PTC100 5009 O 1mA 0 010 1 0mA 0 1ma 0 004 0 01 Q PTC1K 7 5KQ 9 100uA 0 10 1004A 1 0mQ 0 05 0 02 Q Table 6 Accuracy and Resolution for PTC Resistors Note The Model 24C is calibrated with AC excitation User selection of DC excitation will introduce offset errors in temperature measurement 22 Cryo con Model 24C Specifications Features and Functions Thermocouple Sensors Thermocouple devices are supported by using an optional external module Meas
207. vide a pause for a specified number of milliseconds to allow the instrument to react to a command Maximum 20 seconds Generally this is only used with the RS 232 serial interface where there is no hardware handshake lt Pause gt 1000 lt Pause gt lt Delay 1 second gt Group Tags Any tag that is not defined is treated as a group tag They are used to provide structure and enhance readability Otherwise they are ignored Complex Tags Sending a user sensor calibration curve or a PID table to an instrument requires a complex tag because it can require many lines of data User Sensor Calibration Curve lt Calcur gt Send a sensor calibration curve to the instrument lt Download User curve 4 gt lt CalCur gt Calcur 4 lt CalCur gt lt Curve Name gt lt CalCur gt My Sensor lt CalCur gt lt Curve Type gt lt CalCur gt Diode lt CalCur gt lt Multiplier gt lt CalCur gt 1 000000 lt CalCur gt lt Units gt lt CalCur gt Volts lt CalCur gt lt Curve Entries gt lt CalCur gt 0 163300 475 000000 lt CalCur gt lt CalCur gt 0 173300 470 000000 lt CalCur gt lt CalCur gt 0 183400 465 000000 lt CalCur gt lt CalCur gt 1 866000 1 500000 lt CalCur gt lt Send the end of transmission character gt lt CalCur gt lt CalCur gt Transmission of the calibration curve starts with the first CALCUR tag and ends when the end of transmission character is sent Comments are ignored 169 Cr
208. with the shield connected to a metal backshell at both ends Don t send reset RST commands to the controller before reading 154 Cryo con Model 24C Appendix C Troubleshooting Guide Can t talk to IEEE 488 interface Intermittent lockup on the IEEE 488 interface Possible causes Ensure that the GPIB port is selected Press the System key and scroll down to the RIO Port field Ensure that the EOI handshake is set Please review the GPIB Configuration section Check that the controller s address matches the host computer s assignment Press the System key and scroll down to the RIO Address field Debugging tip Cryo con utility software can be used to talk to the controller over the IEEE 488 port using the terminal mode All command and response strings are displayed Since the software provides the proper interface setup it is a good way to establish initial connection Possible causes 1 Bus cables too long or too many loads on a single bus 2 Don t send reset commands before each query This was common in early IEEE 488 systems 3 Ground loops Some equipment manufacturers improperly connect the IEEE 488 Shield Ground wire to their circuit board ground This can cause ground loops with equipment that is properly connected Debug by disconnecting instruments from the bus 4 Use of unshielded bus cables Symptom Can t talk to the LAN interface Possible causes A Category
209. yo con Model 24C Appendix F Configuration Scripts PID tables are sent to the instrument by using standard command tags For example lt PIDtable gt lt Group tag is for documentation only gt lt Command gt PIDTABLE 0 TABLE lt Command gt lt Command gt PID table 1 lt Command gt lt Command gt 320 00 2 10 1 ChA LOW lt Command gt lt Command gt 300 00 2 10 1 ChA LOW lt Command gt lt Command gt 150 00 2 10 1 ChA LOW lt Command gt lt Command gt 55 00 2 10 1 default LOW lt Command gt lt Command gt 40 00 2 10 1 default MID lt Command gt lt Command gt 30 00 2 10 1 default MID lt Command gt lt Command gt 25 00 28 5 1 default MID lt Command gt lt Command gt 20 00 24 1 default MID lt Command gt lt Command gt 15 00 23 1 default MID lt Command gt lt Command gt 10 00 22 1 default MID lt Command gt lt Send end of transmission gt lt Command gt lt Command gt lt PIDtable gt Script File Example lt xml version 1 0 gt lt Transactions gt lt Model gt Model24 Version 3 06 lt Model gt lt Input gt lt CHA gt lt Command gt input a sensor 20 lt Command gt lt Set to PT100 gt lt Query gt input a temp lt Query gt lt Command gt input a sensor 21 lt Command gt lt Set to PT1K gt lt Query gt input a temp lt Query gt lt Ignore response gt lt CHB gt lt Command gt input b sensor 20 lt Command gt lt Query gt input b temp lt Query gt
210. ype Diode Sets the Sensor Type Mult 1 o Sets the sensor Temperature Coefficient and Calibration Curve Multiplier Sets Units of the sensor s Calibration Curve Choices PUES MOLES are Ohms Volts and LogOhm Table 25 Sensor Setup Menu The first line on this menu is the sensor table index Selecting this field allows the user to scroll through all of the sensors configured in the unit including user sensors The index is displayed along with the sensor name Note the sensor name may be entered via any of the Remote UO interfaces but may not be changed from the front panel Sensor Type is an enumeration of all of the basic sensor types supported by the Model 24C Choices are shown in the Supported Sensor Configurations table above The Multiplier field is a floating point numeric entry and is used to specify the sensor s temperature coefficient and to scale the calibration curve Negative multipliers imply that the sensor has a negative temperature coefficient The absolute value of the multiplier scales the calibration curve For example the curve for a Platinum sensor that has 1000 of resistance at 0 C may be used with a 10000 sensor by specifying a multiplier of 10 0 Also note that the temperature coefficient field is only used when the unit is controlling temperature based on the sensor units of Volts or Ohms Units is an enumeration field that identifies the primitive units used by the sensor s calibration curve

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