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Model 32 / 32B User`s Manual - Cryogenic Control Systems, Inc.

1. 136 Manual Calibration nn nncnncnnnns 138 Automatic Calibration 139 Summary of Calibration TYpeS 141 Calibration of Silicon Diodes i 142 Diode Voltage Calibration 142 Constant current Source Calibration eenen 142 Calibration of DC resistors menos 143 Calibration of AC resistors nc cnnnnnnnnnn menos 143 Cryo con Model 32 Remote Operationi utera rane dildo es 145 Remote Interface Configuration 145 IEEE 488 GPIB Configuration ii 145 RS 232 Configuration ii 146 Introduction to Remote Programming 147 INSEruGtions a israeliani il alinea 147 FCAGEIS coccion cial die 147 Truncation Of KeyWordS iaaii 148 SCP Status REGIStEMS 2 oriali alia 149 The Instrument Status Register i 149 The Instrument Status Enable Register 149 The Standard Event Register no 150 The Standard Event Enable Register 150 The Status BVIE aaen did iaia 151 The Status Byte Register ui 151 Remote GommandSs i pa iaia 152 IEEE488 SCPI Common commandsSs ne 152 Control Loop Start Stop commands eese eere nnne nesens 155 SYSTEM commands a ees earan a aaa aeaea an 156 CONFIG commandS
2. 27 Cryo con Model 32 If the Model 32 is controlling temperature loop ON the heater status display shows the loop output as a percentage of full scale This example shows the Heater Status for Loop 2 in a Model 32B controller The unit is in control mode and is 30 10W outputting 30 of full scale output current This means that the output power is 30 2 or 9 of 10 Watts The 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 Loop OFF Htr Off Loop ON 50 output c Note The Model 32 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 28 Cryo con Model 32 Front Panel Menu Operation Instrument Setup Menus The various instrument setup menus are accessed by pressing 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
3. The first one or more characters on a line identify the specific menu For example the first character of every line in the Loop 1 setup menu is the loop identifier which is a superscripted 1 Menus contain several lines so the display must be scrolled by using the and 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 is required M Enumeration entry using the and 4 keys B The line is selected by pressing the Enter key The Setpoint Menu The setpoint menu is accessed by pressing the Set Pt key This gives one key access to the setpoints for both control loops The following 2 line menu will be shown 1Setpoint 320 000K Setpoint 100 000K The pound sign character at the end of the top line is the cursor Use the amp and keys to move the cursor between control loop 1 and 2 The location of the cursor is remembered so that it will point to the same loop each time To enter a new setpoint use the numeric keys and then press the Enter key This will update the setpoint on the selected control loop and return the display to the Home display Press the Home key to exit the menu without update 29 Cryo con Model 32 The Alarm Status Display Menu The current status of the temperature ala
4. 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 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 149 Cryo con Model 32 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 often used to generate an interrupt packet or service request when various l O errors occur Bits in the ESR are defined as follows ESR Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 OPC QE DE EE CE PWR 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
5. iii 82 Basic Setup and Operating Procedures nnn 85 Configuring a SENSOr ii 85 Adding a New Sensor Type nn nc nnnn narnia 86 Sensor SetU tii a e naar ai 86 Calibration Curve Entry ee Girisi aena 87 AOTUN aaa aae aan ii 88 The Autotune Process 88 System Noise and Tuning Modes 0cococcnncocccncococcnnnnncancnonananannnnnn no 88 Pre Tuning and System Stability i 89 System Characterization i 90 Autotune Setup and Execution enn 90 Temperature Ramping enn 93 Operations s e reee lara tela la a 93 Ramping Algorithm i 94 Ramping Parameters and Setup 94 SUMIMALY ni ai nai 94 Cryocooler Signature Subtraction i 95 Synchronous Filter Setup cnn r nana cnn 96 Viewing a Cryocooler Thermal Signature 96 Using an external power booster 98 Direct Connection 100 Adding New Thermocouple Types i 100 Cold Junction Compensation Errors 100 Offset Galibrationi traente lieta 101 Calibration Errors faranno alan 101 AC Power Line Noise Pickup 102 Connecting Grounded Thermocouples 103 CalGen Calibration Curve Generator 105 CalGen Initial Setup tr nsteerrrrrnnnnnssrerrenn renser ent 105 Using CalG
6. 244 Cryo con Model 32 Symptom Condition Can t talk to IEEE 488 interface Possible causes Ensure that the GPIB port is selected Press the Sys key and scroll down to the RIO Port field The IEEE 488 interface does not use terminator characters Rather it uses the hardware EOI handshake Please review the GPIB Configuration section Check that the controller s address matches the host computer s assignment Press the Sys 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 itis a good way to establish initial connection Intermittent lockup on the IEEE 488 interface Possible causes Bus cables too long or too many loads on a single bus Don t send reset commands before each query This was common in early IEEE 488 systems 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 Use of unshielded bus cables 245 Cryo con Model 32 General problems Symptom Condition Controller periodically Generally caused by
7. 251 Introduction leali ai sanas 251 Various methods for obtaining PID coefficients 251 The system provider ceeeeeeeeeeeeeeeeteeeeeeeteeeaeeeteeaaeeeeeeaaees 251 Taking PID values from a different controller 251 Using Factory Default PID values 251 o SE i e PEE EE EA E E iaia 252 Manual TAMNO socia AN EE AE CARRA E Ea 252 Manual Tuning Procedures 252 Ziegler Nichols Frequency Response Method 252 Control Type Arin iiaa EAEE a EAEE la 252 POY Se e rI ted id oda Aa 252 Alternate Meth ds Sirrini iiaae iar 253 Appendix E Sensor Calibration Curve Tables 255 Cryocon S700 Silicon Diode 255 S700 Silicon Diode Connections i 256 STOO MOUNTING x eevee rara al alia 256 vi Cryo con Model 32 Index of Tables Table 1 Model 32 Instrument Accessories cece eeeeeeeeaeceeeeeeesesenaeeeeeeeeess 8 Table 2 Cryogenic AccessorieS nn cc nano nn cc nana n cnc nana nn cr naar nncninns 9 Table 3 Input Sensor Selections ooooocccinonococcccnncccconnonnnncnncnnnnncnnnnnnnnnnnnnnnnnnn nn nnnnnno 12 Table 4 Loop 1 Output Summary nn nanannnnnnnn 13 Table 5 Control Type Summary nono nanno nan nan n cnn rn n rra rn n narran 14 Table 6 Keypad key functions i 22 Table 8 Display Configura
8. at ena eene aea aa eaea AiE 167 STATS commands Input channel statistics 169 INPUT COMMANAS esa ad tad 170 LOOP commands maase la ian 186 OVERTEMP commandS 0 198 CALCUR COMMANOS sc ceo raras drama ai 200 PIDTABLE commandS aaaea eiaa aea aaa 203 CALDATA and SENTYPE CommandS 207 AUTOTUNE commands reaa e eriei EiT 210 INSTCAL commands 216 Remote Command Summary nano ncnnnnnnncncnnnns 221 EU Declaration of Conformity cnn c nano nn rca rca a a iia 231 Appendix A Installed Curves nn cnnnnnnnannnnnnnno 233 Factory Installed Curves i 233 Sensor Curves ON CD ornati 236 Appendix B Troubleshooting Guide 237 Error Displays a aumen aaa alia 237 Control Loop and Heater Problems 239 Temperature Measurement Errors 242 Remote l O problems 244 General problems s ritrae Leali lele aaa 246 Cryo con Model 32 Appendix C Application Note on Signal Dither 247 Using Dither in Digital Control LOOPS i 247 Control AGGUIACYi zaia ATA ani 247 Conventional Control Loop Output 248 The Dither Algorithms a2 sve aio Alana ati 249 How much improvement does dither provide 249 Appendix D Tuning Control Loops
9. The SENTYPE command may be used to query the name of a factory installed sensor at a specific index Command Syntax INPUT lt channel gt ISENIX lt ix gt Where lt channel gt is the input channel parameter and lt ix gt is the desired sensor index Query Syntax INPUT lt channel gt ISENIX Where lt channel gt is the input channel indicator Query Response lt ix gt Where lt ix gt is the sensor index for the selected input channel If the index is invalid a value of 1 will be returned Command Example INPUT B SENIX 0 This command sets the sensor index for input channel B to zero disabled Query Example INP A SENIX Example Response 02 This indicates that sensor 02 is assigned to input channel A The name of factory installed sensor 02 may be accessed using the SENTYPE commands Short Form INP SEN 173 Cryo con Model 32 INPUT USENIX User Sensor index Sets or queries the sensor index number assigned to an input channel for user installed sensors Refer to Appendix A for a description of sensors indices etc An index number of 0 through 3 indicates user sensor curves 0 through 3 Note The use of the ISENIX command to assign a factory installed sensor and the USENIX command to assign a user sensor are preferred to the use of the obsolete SENIX command The CALD command may be used to query information about the user installed sensor curves Command Syntax INPUT lt channel gt USENI
10. 11 AMin 77 0232K a Continuously displays the Minimum temperature on this input channel Pressing the Enter key resets 12 HAccum 1 25 Min a Displays the accumulation time for the input channel statistics Pressing the Enter key resets 33 Cryo con Model 32 ChA ChB Setup Menu cont Displays the variance of the input channel 13 A S2 1 0543 K a temperature over the accumulation time Pressing the Enter key resets the accumulation time Displays the slope or rate of change of AM P the input temperature over the 14 M 1 115 K Min 8 accumulation time Pressing the Enter key resets the accumulation time Displays the offset of the input temperature over the accumulation time The M and b A statistics are the slope and offset of a 15 Ab 76 02 K a straight line fit to the input channel temperature Pressing the Enter key resets the accumulation time Selects sensor bias type Applies only to i a resistor sensors that use constant voltage 16 HBias Volt age 10mVN excitation All others show N A Choices are 10mV 3mV and 1 0mV Table 9 Input Channel Setup Menus Temperature Units Enumeration Default K The Temperature Units field line 1 assigns the units that are used to display temperature for the input channel Options are K for Kelvin C for Celsius F for Fahrenheit and S for sens
11. There is a GAIN factor for each calibration type within a channel Therefore before the INST GAIN is used the INST TYPE command should be used to set the calibration type Command Syntax INSTCAL lt chan gt GAIN lt gain gt Where lt chan gt is the input channel indicator and lt gain gt is the desired gain calibration factor Command Example INST A GAIN 0 999423 Sets the gain calibration factor for input channel A to 0 999423 Query Syntax INSTCAL lt chan gt GAIN Where lt chan gt is the input channel indicator Query Response lt gain gt Where lt gain gt is the gain calibration factor Query Example INSTCAL B GAIN Example Response 0 994321 Indicates that the gain calibration factor for input channel B is 0 994321 Short Form INST lt chan gt GAIN 219 Cryo con Model 32 INSTCAL OFFSET Sets or queries offset calibration factor that is applied to the specified input channel OFFSET is an integer that is in ADC counts and may be either positive or negative There is an OFFSET factor for each calibration type within a channel Therefore before the INST OFFSET is used the INST TYPE command should be used to set the calibration type Command Syntax INSTCAL lt chan gt OFFSET lt offset gt Where lt chan gt is the input channel indicator and lt offset gt is the desired offset calibration factor Command Example INST B OFFSET 321 Sets the offset calibration factor for input channel B
12. c Note The Model 32 expresses 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 Default Loop 1 ChA Loop 2 ChB The input filed selects the control loop source input Any input channel may be selected 38 Cryo con Model 32 Control Loop Range Enumeration Default Loop 1 Low The Range field selects the full scale output for the selected control loop For Loop 1 settings are HI MID and LOW The actual full scale output power is determined by this setting along with the load resistance See the Heater Output Ranges Table for more information The full scale output range for Loop 2 is fixed and cannot be changed by using the Range field For a Model 32 the output is a O to 10Volt voltage source For the Model 32B the output is a 10 Watt linear current source Control Types Enumeration The Type filed selects the actual control algorithm used for the selected loop Selections are Off PID Man Table and RampP 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
13. Adding a New Sensor Type This procedure identifies how to add a new sensor type to the controller If the desired sensor is already installed as a factory installed sensor or previously installed user sensor this procedure is not required These sensors can be simply assigned to an input channel by using the Input Channel Setup Menu described above Adding a new sensor to the Model 32 is a two step process First the sensor type must be defined using the Sensor Setup Menu Next the sensor s calibration curve must be entered by using the Calibration Curve Menu Note that if the new sensor has a lengthy calibration curve entry from the front panel may be tedious In these cases the user may consider entering the sensor via the remote interfaces using the controller s utility software To add a sensor using one of the remote interfaces please refer to the Remote I O section command syntax etc Sensor Setup Sensor Setup Menu 18 gt User Sensor 3 18 gt Type R39R1MA 18 gt Mult 1 0 18 gt Units Volts 18 gt Edit Cal Curve Table 31 Sensor Setup Menu eo rit 7 sr a R O NN gt The new sensor type is defined using the Sensor Setup Menu The first line of this menu includes the Sensor Index 18 and the name User Sensor 3 This line may be scrolled through all of the available sensor types including factory installed sensors Press Enter to select the displayed sensor In order
14. Command Syntax INPUT lt channel gt ALARM HIENA lt status gt Where lt channel gt is the input channel indicator and lt status gt is the status of the high temperature alarm enable lt status gt may be either YES or NO Query Syntax INPUT lt channel gt ALARM HIENA Query Response lt status gt Where lt channel gt is the input channel indicator and lt status gt is the setting of the high temperature alarm enable for lt channel gt lt status gt will be either YES or NO Command Example INPUT A ALARM HIENA NO Disables the high temperature alarm for input channel A Query Example INP B ALARM HIEN Example Response YES Query Command Example INP B ALARM HIGH HIEN NO Example Response 154 2323 The high temperature alarm setpoint for channel B is reported then the high temperature alarm for channel B is disabled Short Form INP lt channel gt ALAR HIEN 179 Cryo con Model 32 INPUT ALARM LOENA Alarm Low Enable Sets or queries the low temperature alarm enable for the specified input channel An alarm must be enabled before it can be asserted Command Syntax INPUT lt channel gt ALARM LOENA lt status gt Where lt channel gt is the input channel indicator and lt status gt is the status of the low temperature alarm enable lt status gt may be either YES or NO Query Syntax INPUT lt channel gt ALARM LOENA Where lt channel gt is the input channel indicator Query Response lt st
15. 3 4 Instrument model and serial number User contact information Return shipping address If the 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 Street Rancho Santa Fe CA 92067 10 Cryo con Model 32 A Quick Start Guide 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 The 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 Several Home Displays are available so that the user can see desired information without additional clutter To scroll through the available displays press the 4 or key Accessing the heater setpoint To instantly access the setpoint for either control loop press the Set Pt key Configuring a temperature sensor Configuring an input sensor from the front panel is performed by using the Input Channel Set
16. Query Syntax SYSTEM REMOTE Query Response lt port gt Command Example SYSTEM REMOTE GPIB Selects the GPIB remote port If the GPIB is already selected it is re initialized and enabled Query Example SYSTEM REMOTE Example Response RS232 Indicates that the current remote port is RS 232 Short Form SYST REMO SYSTEM RESEED Re seed the display filters 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 Command Syntax SYSTEM RESEED Command Example SYSTEM RESEED Short Form SYS RES gt Note The RESEED command is very useful in systems where a computer is waiting for a reading to settle Issuing the RESEED command will reduce the required settling time of the reading 160 Cryo con Model 32 SYSTEM AMBIENT Query Internal Temperature The Model 32 incorporates a temperature sensor into it s internal voltage reference This temperature is essentially the internal temperature of the instrument and may be queried using the SYSTEM AMBIENT command Query Syntax SYSTEM AMBIENT Query Response lt temp gt Where lt temp gt is the internal temperature of the Model 32 in degrees Celsius Query Example SYSTEM AMB Example Response 25C Indicates tha
17. 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 Generally pressing the Home will take the display up one level in the Setup Menu tree and the Home Status displays are at the root level The Enter key is functional only in the Setup Menus and is used to enter numeric data or make a selection 18 Cryo con Model 32 Navigation Keys Esc MM The Keypad and Setup Menu Keys The keypad keys on the far right side of the instrument Navigation through the displays and menus of the Model 32 is accomplished with the cursor keys 4 and Y The 4 and Y keys are used to scroll the display up or down through all of the lines available on a given menu When the display is showing one of the Home Status displays the dk and Y keys are used to scroll through the four available display formats When the display is in any of the Setup menus these keys are used to scroll through the various lines of the menu ChB ChA Loop 1 serve a dual function When numeric data is required E 2 these keys are used as a standard keypad where the O numbers are printed on the keys Otherwise they are used to go directly to the Setup Menu printed over the top Confi S Loop 2 of tne key oloo PID When used as Setup Menu keys their function is identified Auto by a label printed just above the key and is as follows Sen
18. The grounding of this area is identical to the Sensor Area described above Note however that heater elements usually have very low impedance Therefore noise pickup issues are not near the problem that they are in the Sensor Area Digital Circuits The digital circuits of the Model 32 cannot assume that its external connections are floating Therefore it is connected to the Single Point Ground through a Resistor Capacitor network in order to prevent ground loops RS 232 and GPIB connections bring a ground return connection from the host computer This means that the Digital area must be at the same voltage as the host s circuit board ground Otherwise ground loop currents will flow from the host through the instrument and back into the Earth Ground An R C network is used to eliminate common mode voltages from the unit s power supply but also has a high enough impedance to reduce ground loop current flow Further since it is isolated from the other areas of the circuit no current carrying paths can flow through the more sensitive analog circuits The RS 232 Connection The RS 232 connection is a three wire serial communication scheme Two wires carry signals and the third carries a ground reference When either of these interfaces is connected to a Cryo con controller the voltage of the digital area is established by the ground reference of the connected interface Because of the internal R C network connection to grouna little i
19. option 234 Cryo con Model 32 The isenix remote command is used to set factory installed sensors For example the command INPUT B ISENIX 33 would set input B to use the RO 600 sensor INPUT A ISENIX 1 would set input A to use the S700 Diode INPUT A ISENIX 0 would turn input A off by setting the sensor to none 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 Sensor 0 User Sensor 1 User Sensor 2 0 N O 0 N O User Sensor 3 When using the CALCUR commands only user curves are addressed therefore the user index usenix shown above is used The USENIX remote commands address user installed curves For example CALCUR 2 would address user curve 2 INPUT A USENIX 1 would set input A to use User Sensor 1 235 Cryo con Model 32 Sensor Curves on CD The following sensors are available on the CD supplied File Description CryocalD3 crv Cryocal D3 Silicon Diode Range 1 5 to 300K CTldiode crv CTI cryo pump silicon diode Range 10K to 325K Scientific Instruments Inc SI 410 Silicon Diode Range 1 5 to 450K 1410 crv Lakeshore Curve 10 Silicon Diode curve for DT 470 series diodes Range 1 4 to Curve10 crv 495K Lakeshore Curve 10 Silicon Diode curve for DT 670 series diodes Range 1 4 to Curve11 crv 500K
20. A complete procedure for calibrating a diode sensor at three points is shown here Before the procedure can be started the instrument must be connected and have a valid sensor connected The CalGen procedure will require the user to stabalize the input temperature at three user selected points It will capture data at each of these points and then generate a new curve from that data When a 3 point CalGen is started for a Silicon Diode sensor the reference curve must first be selected This is the curve that will be rotated and shifted to fit the selected points open al Look in Sy CalCryostat ex EE E d1041 crv El d1043 crw D67201 crv Files of type Curve Files crv y Cancel Li 127 Cryo con Model 32 When the curve has been selected the following dialog box will appear Enter three reference points x Enter a reference point close to 4 2K Temperature fo Voltage fo Enter a reference point close to 77K Temperature fo Voltage fo Enter a reference point close to 300K Temperature fo Voltage fo Cancel Vapor Pressure The process requires you to completely fill out this dialog box by selecting a temperature and then copying the voltage or resistance reading corresponding to that temperature from the instrument Note that the Vapor Pressure button will take the user to a convenient calculator that will compute the temperature of various cryogens fr
21. Cryocon CP 100 DIN43760 or IEC751 standard Platinum RTD 1000 at 0 C PT100385 crv Range 23 to 1023K DIN43760 or IEC751 standard Platinum RTD 10000 at 0 C Range 23 to 1023K PT1K385 crv Platinum RTD 1000 at 0 C Temperature coefficient 0 003902 Q C Range 73K PT1003902 crv to 833K Platinum RTD 1000Q at 0 C Temperature coefficient 0 00375 Q C Range 73K PT1K375 crv to 833K aufe07cr crv Chromel AuFe 7 Thermocouple Range 3 to 610K TCTypeE crv Thermocouple Type E Range 3 2 to 1273K TCTypeK crv Thermocouple Type K Range 3 2 to 1643K TCTypeT crv Thermocouple Type T Range 3 2 to 673K CX1030E1 crv Cernox CX1030 example curve Range 4 to 325K 236 Cryo con Model 32 Appendix B Troubleshooting Guide Error Displays Display Condition 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 conn
22. Esc or Home key This will cause the field to be de selected and its value will be unchanged 20 Cryo con Model 32 c 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 21 Cryo con Model 32 Summary of keypad functions Key Function Description Bower Toggle power Must be held in for two seconds in order to toggle AC power Stop Disengage all control loops Control Engage all control loops Home Go to the Home Status Display Enter Enter data make a selection Scroll Display UP If in a selection mode abort A Esc entry and return to the Home Status Display Y Scroll Display DOWN p Scroll to NEXT selection 4 Scroll to PREVIOUS selection Display Go to the Display Setup menu Set Pt ta the setpoint value for either control o Alarm Go to the Alarm Status menu 1 ChA Sensor inpu
23. INP B ALARM HIENA LOENA FAULT Example Response YES NO NO Indicates that channel B high temperature alarm is enabled low temperature alarm is disabled and sensor fault alarm is disabled Short Form INP lt channel gt ALAR FAUL 181 Cryo con Model 32 INPUT ALARM AUDIO Audible Alarm Enable The Model 32 contains an audible alarm This alarm may be optionally sounded when any alarm condition is asserted The INPUT ALARM AUDIO command is used to set or query the audible alarm enable for the selected input channel Command Syntax INPUT lt channel gt ALARM AUDIO lt status gt Where lt channel gt is the input channel indicator and lt status gt is the status of the audible alarm enable lt status gt may be either YES or NO Query Syntax INPUT lt channel gt ALARM AUDIO Where lt channel gt is the input channel indicator Query Response lt status gt Where lt status gt is the setting of the audible alarm enable for lt channel gt lt status gt will be either YES or NO Command Example INPUT A ALARM AUDIO YES Enables the audible alarm for input channel A alarm conditions Command Example INPUT A ALARM HIEN OFF AUDIO OFF This command will disable the high temperature alarm and disable the audio alarm for input channel A Query Example INP B ALARM AUDIO Example Response NO Short Form INP lt channel gt ALAR AUD Where AUDIO can be truncated to four characters then to three characters bec
24. Query Example LOOP 1 RANGE Example Response Hi Short Form LOOP RANG 190 Cryo con Model 32 LOOP RAMP Control Loop Ramp Status 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 Command Syntax N A Query Syntax LOOP lt no gt RAMP Where lt no gt is the loop number 1 or 2 Query Response ON or OFF Query Example LOOP 2 RAMP Example Response OFF Short Form LOOP RAMP LOOP RATE Control Loop Ramp Rate Sets and queries the ramp rate used by the selected control loop when performing a temperature ramp Rate is in Units per Minute Command Syntax LOOP lt no gt RATE lt Value gt Where lt no gt is the loop number 1 or 2 and lt Value gt is the ramp rate in Units Minute This may be a value between 0 and 100 Command Example LOOP 1 RATE 0 02 This will set the loop 1 temperature ramp rate to 0 02 If the controlling input channel has units of Kelvin the heater rate will be set to 0 02K min Query Syntax LOOP lt no gt RATE Query Response lt Value gt Query Example LOOP 2 RATE Example Response 0 0100 Short Form LOOP RAMP 191 Cryo con Model 32 LOOP PGAIN Control Loop Proportional Gain term Sets or queries the selected control loop s proportional gain term This is the P term in PID and is a unit less numeric f
25. 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 32 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 32 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 The 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 Bias Voltage Selection Enumeration Default 10mV The Model 32 supports constant voltage AC excitation for resistor sensors Other sensors including diodes are supported by DC constant current excit
26. Where lt channel gt is the input channel parameter and lt ix gt is the desired sensor index Query Syntax INPUT lt channel gt SENIX Where lt channel gt is the input channel indicator Query Response lt ix gt Where lt ix gt is the sensor index for the selected input channel Command Example INPUT B SENIX 0 This command sets the sensor index for input channel B to zero disabled Query Example INP A SENIX Example Response 02 This indicates that sensor 02 is assigned to input channel A The name and configuration of sensor 02 may be accessed using the SENTYPE commands Short Form INP SEN 175 Cryo con Model 32 INPUT ALARM Input Channel Alarm Status 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 There is a 0 25K hysteresis in the assertion of a high or low temperature alarm condition The user selectable display time constant filter is applied to input channel temperature data before alarm conditions are tested Query Syntax INPUT lt channel gt ALARM Query Response lt alarm gt Where lt channel gt is the input channel indicator and lt alarm gt is the alarm status indicators for that channel Query Example INP A ALARM Example Response Which indicates that no alarm is
27. closed loop bandwidth which can be controlled by adjusting PID parameters How much improvement does dither provide Dither causes the average value of the control loop output to converge to the actual desired output How close depends on the number of averages accumulated within the closed loop system The accuracy of an estimate of average value for a fixed number of samples is given by the Chi squared distribution The degrees of freedom used by this function is the number of samples accumulated Using the Cryo con Model 32 the loop output rate is 10 samples per second Therefore if the process being controlled has a time constant on the order of 1 6 seconds a total of 16 samples will be averaged resulting in a factor of four improvement in control accuracy This is equivalent to adding two bits to the output DAC 249 Cryo con Model 32 Since the Model 32 uses a 16 bit output DAC a 1 6 second closed loop time constant will result in the equivalent of an 18 bit DAC Note that 1 6 seconds is an extremely short time constant for a cryogenic temperature process Further Reading Introduction to Signal Processing Sophocles J Orfanidis August 1995 Prentice Hall ISBN 0 13 209172 0 http www ece rutgers edu orfanidi intro2sp 250 Cryo con Model 32 Appendix D Tuning Control Loops Introduction Tuning PID loops to maintain high accuracy control can be a laborious process since the time con
28. nn nn aa ia 17 AS A ari 17 Function KEYS ea ae 17 Navigation O iian kenni SEEE E EE 19 The Keypad and Setup Menu Keys 19 The Selection Keys and Enumeration Fields ns 20 The Keypad Keys and Numeric Data Fields 20 Summary of keypad functions eee eeeeeneeeeeeeneeeeeetaeeeeeeaaes 22 The LED indicators and Audible Alarm 23 The VED Display aa 24 Home Status Displays noc cnn nn rncnnnnnnn 24 Temperature Displays te rstesrtttnrrnrenestrrrrn renne 25 Loop Status DisplayS 27 The Loop Bar Chart Display ne eeeerenr rnn nenesererren nenne 28 Cryo con Model 32 Front Panel Menu Operation nn 29 Instrument Setup Menus 29 The Setpoint Menu nn nnnnnnnnnnnannnnns 29 The Alarm Status Display MENU cnn 30 The Display Configuration Menu i 31 Input Channel Setup Menu 32 The Control Loop Setup Menu nsen 36 User Configurations MENU 42 The System Functions MENU i 43 PID Tables Menu fora ia iano 48 SENSOP OSUUP rana EEE E 51 The Auto Tune Mem i 53 Specifications Features and FUNCHIONS iii 55 Specification SUMMAFry canon cnc EANA RENEE aS 55 Mpu ut elia 60 Constant Current Sensor Excitation cccecceeeeeeee
29. unauthorized 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 32 does not contain any user serviceable parts Do not open the enclosure Do not install substitute part
30. 1 The Model 32 must be controlling temperature and the loop must be stable in terms of both temperature and output power Values for Delta Power and Timeout should be set The Autotune process model is initiated by the command AUTOTUNE START Status can be monitored using the AUTOTUNE STATUS command When a status of complete is indicated the generated values for P l and D may be read Execution of the AUTOTUNE SAVE command will transfer the generated PID coefficients to the actual loop coefficients and continue controlling the process in PID mode Execution of the AUTOTUNE EXIT command at any time will abort the autotune process and discard any generated PID values Refer to the section on autotuning for information about this process 210 Cryo con Model 32 AUTOTUNE DELTAP Maximum Delta in Power Sets and queries the maximum allowed change in heater output power that is allowed during the process modeling phase of the autotuning process This a numeric field that is expressed as a percent of full scale heater output power The actual power output depends on the range setting of the heater If a value of 100 is used the controller may use any output power within the current range Command Syntax lt oc gt AUTOTUNE DELTAP lt value gt Where lt oc gt is the output channel to tune and may be either LOOP 1or LOOP 2 lt value gt is the maximum allowed change in output power expressed as a percent of full s
31. 100 Q a 10uA DC Upper 10 000 Q Lower 1 000 Q Calibration of AC resistors Resistor sensors that use auto ranged AC excitation are calibrated by using the 1mA AC 100uA AC and 10uA AC tabs Resistors required for calibration are as follows a 1mA AC Upper 1000 Lower 100 a 100uA AC Upper 1 000 Q Lower 100 Q a 10uA AC Upper 10 000 Q Lower 1 000 Q 143 Cryo con Model 32 144 Cryo con Model 32 Remote Operation Remote Interface Configuration The Model 32 has two remote interfaces The GPIB IEEE 488 2 and the RS 232 Connection to these interfaces is made on the rear panel of the instrument For specifics about the connectors and cables required refer to the section above on Rear Panel Connections Configuration of the remote interfaces is done at the instrument s front panel by using the Remote I O Setup Menu All configuration information shown on this screen is stored in non volatile memory and once setup will not change when power is turned off or a remote interface is reset IEEE 488 GPIB Configuration The only configuration parameter for the GPIB interface is to set the address This is done by using the System Functions Menu described above Note that each device on the GPIB interface must have a unique address You can set the instrument s address to any value between 1 and 31 The address is set to 12 when the unit is shipped from the factory The controller s GPIB i
32. 3 digits Over Temperature Disconnect Off Remote Interface RS 232 RS 232 Baud Rate 9600 IEEE 488 GPIB Address 12 AC Power Line Frequency 60Hz Cryocooler Filter Off Control on power up OFF To change these press the section key and refer to the Control Loop Sys key and refer to the System Functions Menu Cryo con Model 32 c NOTE Factory defaults may be restored at any time by use of the following sequence 1 Turn power to the Model 32 OFF 2 Press and hold the Enter key while turning power back ON 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 Model 32 Basic controller with two standard input channels Outputs are Loop 1 50Watt 3 range linear heater and Loop 2 0 5Volt analog output Model 32B Controller with two standard input channels Outputs are Loop 1 50Watt 3 range linear heater and Loop 2 Ten Watt linear heater The only option that can be ordered with a Model 32 or 32B is a single thermocouple input for sensor B These variations are Model 32B T Model 32B with one standard input plus one universal thermocouple input Model 32 T Model 32 with one standard input plus one universal thermocouple input Ordering Information Standard Model 32B Description Controller with two standard multi function Model 32 Model 32B s
33. 325K SI 410 Diode Scientific Instruments Inc 410 Diode Curve Range 1 5 to 450K Pt100 385 DIN43760 standard 1000 Platinum RTD Range 23 to 1023K 1mA excitation Pt1K 385 10000 at 0 C Platinum RTD using DIN43760 standard calibration curve Range 23 to 1023K Pt10K 385 10KQ at 0 C Platinum RTD Temperature coefficient 0 00385 Range 23 to 475K RhFe 27 1mA Rhodium lron resistor 27 Ohms at 0 C 1mA DC excitation RO 105 AC Scientific Instruments Inc RO 105 Ruthenium Oxide sensor with constant voltage AC excitation RO 105 DC 104A Scientific Instruments Inc RO 105 Ruthenium Oxide sensor with constant current 10uA DC excitation RO 600 AC Scientific Instruments Inc RO 600 Ruthenium Oxide sensor with constant voltage AC excitation User Sensor 1 User supplied sensor 1 User Sensor 2 User supplied sensor 2 User Sensor 3 User supplied sensor 3 User Sensor 4 User supplied sensor 4 Table 3 Input Sensor Selections 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 return to the Home Status display 12 Cryo con Model 32 Configuring the Loop 1 Output Before using the Loop 1 main heater control output it is essential that
34. 32B controller always assumes a 500 load Command Syntax LOOP 1 LOAD lt load gt Where lt load gt is the desired resistance of the selected control loop load from the above list Query Syntax LOOP 1 LOAD Query Response lt LOAD gt Command Example LOOP 1 LOAD 50 Sets the primary heater output for a 504 load Query Example LOOP 1 LOAD Example Response 25 Short Form LOOP LOAD 195 Cryo con Model 32 LOOP MAXPWR Heater Maximum Output Power Sets or queries the maximum output power setting of the selected control loop Please refer to the discussion on maximum output power in the Control Loop Setup Menu section Command Syntax LOOP lt no gt MAXPWR lt MaxPwr gt Where lt no gt is the loop number and lt MaxPwr gt is the desired maximum output power limit expressed as a percentage of full scale Query Syntax LOOP lt no gt MAXPWR Query Response lt MaxPwr gt Command Example LOOP 1 MAXPWR 50 Sets the maximum output power limit on loop 1 to 50 of full scale Query Example LOOP 1 MAXPWR Example Response 25 Short Form LOOP MAXP LOOP MAXSET Control Loop Maximum Setpoint Sets or queries the maximum allowed set point for the selected control loop Please refer to the discussion on Maximum Setpoint in the Control Loop Setup Menu section Setpoint units are the currently selected display units for the controlling input channel Command Syntax LOOP lt no gt MAXSET lt
35. 5 1 2 4 8 16 32 or 64 Seconds SYSTEM ADRS SYSTEM ADRS Set or query the address that the IEEE 488 2 interface will use SYSTEM RESEED Reseeds the display filter for all of the input channels resulting in faster settling SYSTEM SYNCTAPS Sets the number of taps used by the synchronous filter SYSTEM REMOTE Sets the remote interface port Choices are GPIB and RS232 221 Cryo con Model 32 Command Function SYSTEM AMBIENT Query the temperature of the controller s internal voltage reference Example Output 25C SYSTEM AUTOCAL Perform an autocalibrate sequence on both input channels Generally used only to correct for errors caused by significant changes in operating temperature SYSTEM HTRHST Query the temperature of the internal LOOP 1 heatsink Example output 62C SYSTEM HOME Causes the display on the front panel to go to the Operate Screen SYSTEM NAME SYSTEM NAME Set or query the instrument s name string Example SYSTEM NAME Cryocooler Four SYSTEM DRES SYSTEM DRES Sets or queries the controller s display resolution Choices are Full 1 2 or 3 SYSTEM HWREV Queries the instrument s hardware revision level SYSTEM FWREV Queries the instrument s firmware revision level SYSTEM ERROR Queries the instrument s error queue SYSTEM CJTEMP Queries the internal Cold Junction Compensation temp
36. 5 1mK 600K 4mK 300K 4 7mK 300K 4mK 77K 1 1mK 77K 0 5mK 30K 2 4mK 30K 1 0mK 300K 4mK 77K 0 5mK 30K 1 0mK Control Stability Power Dissipation 4 2K 17uW 30K 3 7uW 30K 370nW 30K 37nW P 77K 12uW 77K 20uW 77K 2 0uW 77K 200nW Magnesio Very Large Moderate Moderate Moderate resistance Table 22 Sensor Performance for Diodes and Pt Sensors 66 Cryo con Model 32 1 4K 520KQ K 1 4K 240KQ K ee 1 0K 12600 K 42K 4220 K 4 2K 22900 K Sensor Sensitivity 4 2K 80 30 K r K sta 77K 0 10 K 77K 2 15Q K mae 300K 0 019 K 300K 0 160 K 1 4K 7280 1 4K 6750 Measurement a 4 2K 0 580 4 2K 5 10 Accuracy 20K 1 090 77K 14mQ 77K 161mQ di 300K 0 020 300K 40mQ 1 4K 1 4mK 1 4K 2 2mK a yee pati 4 2K 1 4mK 4 2K 22mK pa ria 77K 150mK 77K 75mK CCUIACY i 300K 2 1K 300K 295mK Fase 2 0K 11mQ 4 2K 11mQ 4 2K 46mQ Be Firion 4 2K 11mo 77K 0 2mQ 77K 1 8mQ 20K 11mQ 300K 0 2mQ 300K 0 5mQ 2 0K 32uK 4 2K 30uK 4 2K 50K ae 4 2K 0 13mK 77K 1 2mK 77K 0 85mK 20K 2 9mK 300K 12mK 300K 3 5mK 2 0K 0 15mK 4 2K 0 15mK 4 2K 0 15mK Control Stability 4 2K 0 15mK 77K 35mK 77K 0 15mK 20K 2 9mK 300K 250mK 300K 35mK a 1 0K 42nW 1 4K 962pW 1 4K 1 1nW Fower Dissipation 43K 73nW 4 2K 171nW 4 2K 20nW MEE ees lt 2 for H lt 2T Moderate lt 1 for H lt 2T resistance 10mV Constant Voltage bias Table 23 Sensor Performance
37. FLASH memory Therefore this command should only be issued once when the entire procedure is complete Command Example INST A SAVE Short Form INST lt chan gt SAVE 217 Cryo con Model 32 INSTCAL TYPE Sets or queries the type of calibration that is being applied to a specified input channel This command is only effective when the unit is in calibration mode Calibration types are shown below V10UA Voltage calibration Full scale is 2 5V 110UA 10UA constant current source calibration R1MA Resistance calibration Full scale is 25000 R100UA Resistance calibration Full scale is 25KQ R10UA Resistance calibration Full scale is 250KQ Command Syntax INSTCAL lt chan gt TYPE lt type gt Where lt chan gt is the input channel indicator and lt type gt is the desired calibration type from the above list Command Example INST A TYPE R10UA Places the calibration type to R10UA Query Syntax INSTCAL lt chan gt TYPE Where lt chan gt is the input channel indicator Query Response lt type gt Where lt type gt is the calibration type from the above list Query Example INSTCAL lt chan gt TYPE Example Response V10UA Indicates that the calibration type is V10UA Short Form INST lt chan gt TYP 218 Cryo con Model 32 INSTCAL GAIN Sets or queries gain calibration factor that is applied to the specified input channel GAIN is a floating point number with a nominal value of 1 000
38. PID for standard PID control 4 Off In this mode the controller will not apply power on this output channel Note that the Model 32 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 For 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 39 Cryo con Model 32 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 For Loop 1 the Power Limit is applied to the HI range only For lower power levels on this loop select either the MID or LOW range For Loop 2 the Power Limit is always applied gt 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 0K Setpoint values use the temperature units selected for the controlling i
39. Q2 This process of jumping between Q2 and Q3 will continue establishing an oscillation with an amplitude of one quantization level and a frequency related to the system s closed loop time constant 248 Cryo con Model 32 The Dither Algorithm The signal dithering algorithm used in Cryo con s digital control loop first generates a dither signal that is a random number within the range of 0 5 of a quantization level This is then added to the loop output value just before placing it in the DAC If the sum of the desired output plus the dither value is above the midpoint between Q2 and Q3 the DAC will output Q3 If it A eee is below the midpoint the DAC will a4 E output Q2 Therefore the DAC output to toggles randomly between Q2 and Q3 i cinc but the number of times at one level vs Q3 the other is weighted by how close the E Sr RARO desired output is to the nearest RS o quantization level In this example the desired output is E 25 of the distance from Q3 to Q2 fw Therefore 75 of the DAC output Q1 samples will be Q3 and the remaining at Most importantly the average value of the DAC output converges to the desired output loop value Using this dither technique the control loop output accuracy will improve as the number of averages increases up to the limits imposed by the other elements of the control loop Fortunately the number of samples averaged in a given system is proportional to its
40. The Model 32 is returned to normal operation by using the INSTCAL MODE OFF command Note that this does not write data to the calibration FLASH memory area 216 Cryo con Model 32 INSTCAL MODE Queries or sets the instrument calibration mode Calibration mode must be turned on before most instrument calibration commands are effective Command Syntax INSTCAL lt chan gt MODE lt mode gt Where lt chan gt is the input channel number required but not used and lt mode gt is the desired mode which may be either ON or OFF Command Example INST A MODE ON Places the Model 32 in calibration mode Query Syntax INSTCAL lt chan gt MODE Where lt chan gt is the input channel number required but not used Query Response lt mode gt Where lt mode gt is the calibration mode indicator and will be either ON or OFF Query Example INSTCAL lt chan gt MODE Example Response OFF Indicates that the Model 32 is not in calibration mode Short Form INST lt chan gt MOD INSTCAL SAVE This command copies the temporary RAM calibration data table to the actual FLASH memory instrument calibration area It can only be used when the instrument is in calibration mode Otherwise it does nothing Command Syntax INSTCAL lt chan gt SAVE Where lt chan gt is the input channel number required but not used Note that even though a channel indicator is specified the entire RAM table for all four input channels is copied to
41. and bar graph Detailed status of control loop 2 Temperature of controlling input channel set point heater status and bar graph Control loop status Displays the status of both control loops on the second line of the display On the first line the temperature of the controlling input is shown Temperature statistics for input channel A Shows current temperature maximum minimum and accumulation time For additional statistical information refer to the Input Channel Setup Menu Note Pressing the Enter key will reset the statistics Temperature statistics for input channel A Shows current temperature maximum minimum and accumulation time For additional statistical information refer to the Input Channel Setup Menu Note Pressing the Enter key will reset the statistics Table 8 Display Configurations Select the desired configuration and press the Enter to return to the Home display Refer to the section Home Status Displays for more information 31 Cryo con Model 32 Input Channel Setup Menu The Input Channel Setup menus are selected by pressing the ChA or ChB keys from a Home Status Display These menus contain all of the user configurable parameters for a selected sensor input channel The first character on each line of these menus is always the input identifier which is a superscripted A or B for Input A or Input B Us
42. are 1 through 12 120 Cryo con Model 32 When OK is selected the sensor calibration curve will be downloaded to the instrument During the transfer curve data points will be displayed in the window s main pane Upon completion the Download Complete dialog box will appear Cryo con Utility Software dloader loj x File Comm Firmware Calibration Table PID Table View DataLogging Help 155 449997 163 369995 171 289993 179 210007 187 139999 195 059998 202 979996 210 899994 218 820007 226 740005 234 660004 242 589996 250 509995 258 429993 266 350006 274 269989 282 190002 290 109985 298 040009 305 959991 313 880005 321 799988 Ready 413 149994 433 149994 453 149994 473 149994 493 149994 513 150024 533 150024 553 150024 573 150024 593 150024 a 613 1500 Download Upload Message xl 633 15007 653 15007 673 1500 Downloading to Calibration Curve 1 Please wait 693 1500 RARO anananarnaaran 713 1500 0 MENA AAA 100 733 1500 753 1500 113150027 ERNST xl 793 150024 813 150024 A Download Complete 833 150024 Dismiss this dialog box to complete the download process To upload a calibration curve use the same procedure and select Upload This will transfer a curve from the instrument to the PC 121 Cryo con Model 32 Downloading or Uploading a PID Table A PID table may be transferred to the instrument by selecting PID Table gt Download from the
43. bars PID Table Edit Menu 1 01 IX IE 2 101 SP 100 0000 Line setpoint entry 3 01 P 20 0000 LineP gain entry 4 01 I 10 0000 Line gain entry 5 O1 D 2 0000 LineD gain entry 6 101 Range LOW H aay This entry is Save the table and exit by pressing the 7 01 SaveTable amp Exit Enterkey Exit without saving by pressing the Esc or Home key Table 14 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 an index is selected all of the lines on this menu will be updated to show the selected index 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 Note the heater range entry is ignored for Loop 2 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 50 Cryo con Model 32 Sensor Setup The Sensor Setup menu is used to view and edit user temperature sensor data The Sensor
44. by setting the setpoint to any negative number 48 Cryo con Model 32 The PID Table Menu The PID Table Menu is accessed by pressing the PID Table key from the Home Display The first three characters of each line on the initial PID Table menu are a two digit index followed by a single vertical bar The index identifies the currently selected table and will change whenever the table number is updated PID Table Menu 4 01 PID Table 1 H Sets the PID table number for editing Selections are 0 to 3 Displays the number of zones in the selected PID table Note This number 2 01 I N 5 is generated from the selected table and cannot be changed in this menu Pressing the Enter key on this line will take the display to the second level 3 01 l Edit PID Table e menu where the selected table is entered Table 13 PID table Menu The first line 01 is the table index This field is used to select a table for editing Below this is N the number of valid entries in the table This number was generated when the user entered table and cannot be changed using this menu 49 Cryo con Model 32 The PID Table Edit Menu The EDIT PID TABLE line is selected to enter and edit zones within the selected table This will take the display to the PID Table Edit Menu shown below The first four characters of the PID Table Edit Menu show the selected table index followed by TWO vertical
45. display To edit an enumeration field place the cursor at the desired field by using the Navigation keys Then use the or 4 key to scroll through all of the possible choices in sequence When a field has been changed a block cursor will flash over the M symbol Each time the or 4 key is pressed the field value will scroll forward or backward through all of the available choices 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 M symbol The Keypad Keys and Numeric Data Fields A numeric data field is indicated by a pound sign in the last column of the display The Keypad Keys are used to enter data into numeric fields These keys are the numerals 0 through 9 the period key 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 database will be correspondingly updated If the numeric entry is outside of the required range an error is indicated by the display of the previous value of the field Once the entry of numeric data has started it can be aborted by pressing the
46. heater Loop 1 the range is also shown Range settings may be either Hi Mid or Low The range is set in the Loop 1 menu For the secondary output or Loop 2 the range will be shown as 10W for a Model 32B or 10V for a Model 32 2 Overtemp indicates that the controller s Internal Temperature Monitor circuit shut off the heater This fault is usually the result of a shorted heater or use of a heater with 1 Overtemp significantly less resistance than the selected load resistance 3 Readback indicates that the Current Readback Monitor circuit has shut down the heater This monitor compares the actual heater output Current with the indicated 1 output Current and asserts a fault condition if Readback there is a difference This fault is usually the result of a broken heater cable or an open heater 4 SensorFLT indicates that the heater was shut down by a fault condition on the on the controlling input channel This is usually caused by an error in the sensor or sensor cables None A sensor fault will not shut down the heaters if the loop is in Manual iSensorFlt output mode 5 OTDisconn indicates that the heater output was disconnected by the Over Temperature Disconnect Monitor This monitor is configured by the user and functions to disable the heater if a specified over temperature condition is exists on a selected input channel See the Sys menu for information on how to configure and 10TDisconn use this important feature
47. implemented using 32 bit floating point Digital Signal Processing techniques Enhancements include 1 Implementation of a user settable damping factor that can be used to minimize overshoot to a new setpoint without affecting the PID loop operation 2 Noise filtering on the derivative term The D term will provide better control stability but is often not used because without filtering it can make the control loop too sensitive to noise 3 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 4 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 P 1 D and heater range values based on the specified setpoint 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
48. in each PID table Each entry contains a setpoint P and D coefficients and a heater range Either output channel may use any table The heater range field only applies to Loop 1 However it must be specified in each entry The format of an entry is lt setpoint gt lt P gt lt I gt lt D gt lt Heater Range gt Fields are separated by a white space The entry is terminated by a new line n character if the table is transmitted via the RS 232 interface and is not terminated for all others 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 heater range is an enumeration field that may have the following values Hi Mid and Low The file format of a PID table is shown below lt name gt lt entry 0 gt lt entry 1 gt lt entry N gt 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 A line that contains only a single semicolon indicates the end of the table 203 Cryo con Model 32 An example of a sixteen entry PID Table is as follows PID Test O 300 00 1 60 160 00 40 00 HI 280 00 1 50 150 00 30 00 HI 260 00 1 40 140 00 30 00 HI 240 00 1 30 130 00 30 00 HI 220 00 1 20 120 00 30 00 HI 200 00 1 10 110 00 20 00 HI 180 00 1 00 100 00 20 00 MID 160 00 0 90 90 00 20 00 MID 140 00 0 80 80 00 20 00 MID 120 00 0 70 7
49. it cannot generate a solution because of issues in the system dynamics it will indicate a status of Fail Autotune times out and does not generate effective PID parameters Extend the Display Filter time constant to reduce system level noise and try autotune again The display filter is described in the System 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 241 Cryo con Model 32 Temperature Measurement Errors Symptom Condition Noise on temperature measurements Possible causes Excessive noise pickup especially AC power line noise Check your wiring and shielding Sensors must be floating so check that there is no continuity 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 som
50. 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 Sys key and refer to the System Functions Menu section Cryo con Model 32 Factory Default Setup A controller with factory default settings will have an operational display like the one shown here The dash or dot characters indicate that there is no sensor connected Note that 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 unconnected Input Channel factory defaults are Sensor Units Kelvin 1 Off Hi Off 10W Sensor Type LS DT 670 Lakeshore DT 670 Curve 11 Silicon Diode Bias Type DC Alarm Enables Off To change these press the Setup Menu section ChA or ChB Control Loop factory defaults are Setpoint 100K key and refer to the Input Channel P gain 5 0 gain 28 0 Seconds D gain 8 0 Manual output power Pman 5 Control input channel A for Loop 1 B for Loop 2 Loop 1 Range Low Control Type Manual Heater Resistance 250 To change these press the Setup menu section Loop 1 or Loop 2 Instrument setup factory defaults are Display Filter Time Constant 2 0 Seconds Display Resolution
51. main menu toolbar PID tables are transferred from the instrument to the PC by using PID Table gt Upload From this point the sequence is identical to the calibration curve transfer process described above Using the Real Time Strip Charts The real time strip chart feature of the Utility Software lets the user continuously display any combination of input channels on the computer display This function is initiated by selecting the View command on the Utility Software s main toolbar then selecting the desired channels to monitor A strip chart will be displayed for each channel selected The dialog box will show the channel s Input Identifier Name String and a chart of current temperature Channel B 3 0 0 na Manual The update rate of the chart is locked to the program s Data Logging Interval The section below details how to set this value 122 Cryo con Model 32 Data Logging The Utility Software will perform data logging on all of the instruments input and control output channels The result is a disk file in Comma Separated Value or CSV format This format is compatible with any data analysis or charting software including Microsoft Excel To initiate data logging select the Data Logging button from the Utility Software s main menu The Data Logging Setup dialog box will now appear Data Logging Setup Dialog On this dialog box check the desired channels and set an Interval
52. 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 Sys menu and scroll down to A the field AC Line field Then select Sync Filt Taps 07 60 or 50 Hz as required AC Line 60Hz H 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 For most cryocoolers a setting of 7 is used since this is the most common sub multiple of the AC line frequency used c Note If you are not using a cryocooler please leave the Sync Filt Taps field set at the default of 7 gt Note If you change the setting the Sync Filt Taps setting you will need to re tune the PID control loop 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 zo
53. 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 32 is not affected by this setting Display Brightness Enumeration Default 2 The SYS Brightness field is used to control the brightness of the display Selections are 0 1 2 and 3 with O being the brightest This control does not take effect until the next power up Over Temperature Disconnect The Over Temperature Disconnect OTD feature is configured using the OTD lines This feature allows the user to specify an over temperature condition on any of the input channels Whenever an over temperature condition exists on the selected channel the heaters outputs are disconnected and the Loop Status indicator is set to OTDisconn Both loops are disconnected when an over temperature condition exists A mechanical relay is used 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 will be asserted Te
54. panel to go to the Operate Screen Command Syntax SYSTEM HOME Command Example SYSTEM HOME Short Form SYST HOME SYSTEM SYNCTAPS Synchronous filter setup Sets or queries the number of taps in the synchronous filter This is an advanced setup function The default is 7 taps Command Syntax SYSTEM SYNCTAPS lt taps gt Where lt taps gt is the number of taps Query Syntax SYSTEM SYNCTAPS Query Response lt taps gt Where lt taps gt is number of taps used by the synchronous filter Query Example SYSTEM SYNCTAPS Example Response 7 Short Form SYST HTRH 162 Cryo con Model 32 SYSTEM NAME Unit 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 Use the SYSTEM ADRS command to assign a unique address Command Syntax SYSTEM NAME lt name gt Where lt name gt is the desired system name string and is a maximum of 15 ASCII characters Command Example SYSTEM NAME Cryocooler Four This assigns the name Cryocooler Four to the unit so that it may be uniquely identified Query Syntax SYSTEM NAME Query Response lt name gt Where lt name gt is the temperature of the internal heater output stage s heat sink in Celsius Query Example SYSTEM NAME Example Response Model 32 Unit 0 Short Form SYST NAM SYSTEM HWREV Instrument Hardware Revision Level Queries the instrument s hard
55. parameter and lt units gt is the display units indicator lt units gt 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 selected for the input channel Query Syntax INPUT lt channel gt UNITS Where lt channel gt is the input channel indicator Query Response lt units gt Where lt units gt is the display units indicator which will be K C F V for Volts or O for Ohms Command Example INPUT B UNITS F Query Example INP A UNIT Example Response K Query Example INP A TEMP UNIT Example Response 27 9906K Short Form INP UNIT 171 Cryo con Model 32 INPUT SENPR Input Reading in Sensor Units The INPUT SENPR query reports the reading on a selected input channel For diode and thermocouple 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 Syntax INPUT lt channel gt SENPR Where lt channel gt is the input channel parameter of A or B Query Response lt rdg gt Where lt rdg gt is the reading of the specified input channel in Ohms or Volts Query Example INP B SENPR Example Response 124 5933 meaning 124 5933 Ohms Short Form INP lt channel gt SENPR INPUT VBIAS Input chann
56. reset sequence will take about 15 seconds to complete During that time the instrument will not be accessible over any remote interface The RST command sets the Model 32 to it s last power up default setting Command Syntax RST 154 Cryo con Model 32 Control Loop Start Stop commands STOP Disengage control loops The STOP command will disengage all control loops and disconnect their heaters Command Syntax STOP CONTROL Engage Control Loops 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 As a query the command will report the status of the loops as ON or OFF Command Syntax CONTROL Command Example CONT Query Syntax CONTROL Query Response lt status gt Where lt status gt is ON or OFF Query Example CONT Example Response OFF Indicating that the control loops are OFF or disengaged Short Form CONT 155 Cryo con Model 32 SYSTEM commands SYSTEM commands are a group of commands associated with the overall status and configuration of the Model 32 rather than a specific internal subsystem SYSTEM LOCKOUT Keypad Lockout Sets or queries the remote lockout status indicator This command is used to enable or lock out the front panel keypad of the Model 32 thereby allowing or preventing keypad entry during remote operation The default condition for this ind
57. significant AC coupling into the sensor However if the connection procedures described above are carefully followed ground loops through the sensor leads will be avoided When a grounded sensor is used a poor quality ground may have sufficient AC voltage to exceed the input range of the controller 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 insufficient grounding is usually the root cause of this type problem 102 Cryo con Model 32 Most common AC noise pickup problems are caused by capacitive or magnetic coupling into the sensor wires Again the thermocouple s high resistance leads make this type coupling very efficient General recommendations to minimize coupling include 1 Minimize the length of thermocouple wires For example use a thermocouple Module near the sensor to convert the thermocouple wires to copper as soon as possible 2 Twist the wires Twisted wire for various types of thermocouples is available from several vendors Avoid running sensor wires near or parallel to AC power lines Use the largest diameter sensor wires possible Lowest AWG This will reduce the lead resistance and therefore reduce coupling However in many cryogenic applications wire size must be kept small because thermocouple wire is a good heat conductor Connecting Grounded Thermocouples For best performan
58. to install a new sensor one of the four user sensors should be selected Next the Type of sensor must be defined Choices include Silicon Diodes various resistors and thermocouples This selection will identify the excitation current and voltage input range that the controller must use to interface with the sensor Selections are given in Table 2 above The Multiplier field specifies a multiplier that is applied to the sensors calibration curve The sign of this field indicates the temperature coefficient This coefficient is 86 Cryo con Model 32 only used when the user is attempting to control on sensor units such as Ohms or Volts Most commonly the multiplier field contains a value of plus or minus 1 0 This causes the controller to apply the sensor calibration curve directly without first scaling it Further a negative value will indicate that the sensor has a negative temperature coefficient and a positive value will indicate a positive coefficient Diode sensors will generally have a Multiplier of 1 0 since their temperature coefficient is negative and no scale is applied to the calibration curve 100Q Platinum sensors will use a Multiplier of 1 0 However if a 10000 sensor is used with a calibration curve for 1000 sensors a Multiplier of 10 0 should be used Units is an enumeration field that identifies the basic units used by the sensor s calibration curve Choices are Volts Ohms and LogOhm LogOhm selects t
59. to monitor input channel ChB Short Form OVER SOUR OVERTEMP TEMP OTD Maximum Temperature 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 Command Syntax OVERTEMP TEMP lt temp gt Where lt temp gt is the desired temperature Query Syntax OVERTEMP TEMP Query Response lt temp gt Where lt temp gt is the setpoint temperature in units of the controlling input chamnel Command Example OVER TEMP 123 4 Sets the over temperature disconnect to trip when a temperature of 123 4 is exceeded Query Example OVERTEMP TEMP Example Response 54 23 Which indicates that the over temperature disconnect is set to a temperature of 54 23 Short Form OVER TEMP 199 Cryo con Model 32 CALCUR commands The CALCUR commands are used to transfer sensor calibration curves between the controller and the host controller Curves are referenced by an index number In the Model 32 there are four user curves numbered 1 through 4 In the Model 34 and 62 there are 12 user curves numbered 1 through 12 The CALCUR data block consists of a header multiple curve entries and a terminator character The header consists of four lines as follows Sensor Name Sensor name string 15 characters max Sensor Type Enumeration See Sensor Types table Multiplier Signed numeric Units Units of calibration curve OHMS VOLTS or L
60. value in Seconds The minimum interval is 0 1 Second 123 Cryo con Model 32 When the Start button is clicked a file selection dialog box will be shown gt Cryo con Utility Software dloader my File Comm Firmware Calibration Table PID Table View DataLogging Help I zx Save in Ea Customer cD e e E Save as type MSExcel Comma Separated Value Files css y Cancel 4 From this dialog box enter a file name and select the directory where data logging results will be saved As soon as the Save button is clicked the software will begin continuous data logging to the specified file While data logging is in progress a dialog box will be displayed that allows the user to stop logging When this Stop button is clicked logging is stopped and the log file is closed 124 Cryo con Model 32 Remote I O command HELP Help for the remote interfaces and remote commands is available by clicking on the HELP gt Contents button from the Utility Software s main menu A standard HELP screen will be shown that is indexed and searchable gt Cryo con Utility Software dloader iol xj File Comm Firmware Calibration Table PID Table View DataLogaing Help Help Topics Cryocon Remote Interface Help Contents Index Find Click a topic and then click Display Or click another tab such as Index Remote Interface Configuration ta Remote 1 0 Data Types 2 Instrument Status Register ISR A Instrum
61. 0 00 10 00 MID 100 00 0 60 60 00 10 00 MID 80 00 0 50 50 00 10 00 MID 60 00 0 40 40 00 10 00 LOW 40 00 0 30 30 00 0 00 LOW 20 00 0 20 20 00 0 00 LOW 10 00 0 10 10 00 0 00 LOW Entries may be sent to the Model 32 in any order The unit will sort the table in ascending order of setpoint before it is copied to Flash RAM Entries containing invalid numeric fields will be deleted 204 Cryo con Model 32 PIDTABLE PID Table Name Query Queries the name string of a PID table at a specified index Query Syntax PIDTABLE lt index gt Query Response lt name gt Where lt index gt is the index to the PID table list and lt name gt is the name string associated with the specified table Index may be from zero to five Query Example PIDT 2 Example Response Joe s Cooler Indicates that PID table 2 is named Joe s Cooler Short Form PIDT PIDTABLE NAME PID Table Name Sets or queries the name string of the PID Table at a specified index The name string is used to associate a convenient name with a PID table It may include up to 15 ASCII characters Command Syntax PIDTABLE lt index gt NAME lt name gt Where lt index gt is a numeric index 0 3 to the PID table list and lt name gt is an ASCII name string in double quotes Query Syntax PIDTABLE lt index gt NAME Query Response lt name gt Where lt index gt is the index to the calibration curve list lt name gt is the name string associated with the spe
62. 0 Diode Curve Range 1 5 to 450K 10uA 5 S1410 DIAS excitation 6 Cryocon S800 Cryo con S800 series Silicon Diode Range 1 4 to 380K 10uA constant current excitation 7 Cryocon S900 Cryo con S900 series Silicon Diode Range 1 5 to 500K 10uA constant current excitation 8 CTI Diode CTI Cryopump diode 10K to 325K 20 Pt100 385 DIN43760 standard 1000 Platinum RTD Range 23 to 1023K 1mA excitation 21 PHK 385 10002 at 0 C Platinum RTD using DIN43760 standard calibration curve Range 23 to 1023K 100nA excitation 10KQ at 0 C Platinum RTD Temperature coefficient 0 00385 Range 23 22 EHRs to 475K 10uA excitation 23 RhFe 27 1mA Rhodium Iron resistor 27 Ohms at 0 C 1mA DC excitation Scientific Instruments Inc RO 600 Ruthenium Oxide sensor with A RO 600 AC constant voltage AC excitation Scientific Instruments Inc RO 105 Ruthenium Oxide sensor with ss RO 105 DC T0pA constant current 10uA DC excitation Cryocon R500 Ruthenium Oxide sensor with constant voltage AC 33 R500 os excitation Cryocon R400 Ruthenium Oxide sensor with constant current 10uA DC 34 R400 Ra excitation 45 TC type K Only available when thermocouple option is installed thermocouples type 46 TC type E K E and T Direct input to the controller Range Type T 3 5 to 673K 47 TC type T Type E 3 5 to 1273K Type K 3 5 to 1643K 48 AuFe 0 07 Table 38 Factory Installed Sensors Note that Thermocouple devices only appear on units ordered with the thermocouple
63. 2 Cryo con Model 32 e Keep Away From 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 not replace components with power cable connected To avoid injuries always disconnect power and discharge circuits before touching them e Cleaning Do not submerge instrument Clean exterior only with a damp cloth and mild detergent only e 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 83 Cryo con Model 32 Safety Symbols O H Ae Equipment protected throughout by double insulation or reinforced insulation equivalent to Class Il of IEC536 Direct current power line 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 Db o Fuse Off AC Power Environmental Conditions Environmental conditions outside of the conditions below may pose a hazard to
64. 2 0050 Temperature Units are always in Kelvin 3 18 gt gt S 1 00002 Sensor reading Units are taken from the Sensor Setup menu described above 4 18 gt gt SaveCurve amp Exit E Pressing Enter will display the next level menu where the sensor s Calibration Curve data may be viewed and edited Table 16 Calibration Curve Menu The Auto Tune Menu The Model 32 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 53 Cryo con Model 32 54 Cryo con Model 32 Specifications Features and Functions Specification Summary User Interface Display Type 20 x 2 character VFD 9mm character height Number of Inputs Displayed Two 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 two input channels each of which may be independently configured for any of the supported sensor types Sensor Connection 4 wire differential DIN 5 input connectors mate with either DIN 5 or DIN 6 plugs Connections are described in the Sensor Connections section Supported Sensors Include Type Excitation Temperature Range Cernox M Constant Voltage AC 0 3 to
65. 2 s measurement electronics are also effectively cancelled c 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 near 77K When the CalGen menu is re entered for curve generation the point captured at 300K is still valid CalGen Initial Setup Generation of a calibration curve using CalGen requires the measurement 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 will take the screen to a sub menu for the specific sensor type gt 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 will determine if the sensor is a Diode Platinum or a thermocouple sensor Further the calibration curve of the selected input sensor will be used as the input to the curve generation process 105 Cryo con Model 32 106 Cryo con Model 32 Using CalGen With Diode Sensors Options for generating Diode
66. 420K Ruthenium Oxide 200mK to 273K hermistors 70 to 325K Rhodium lron 1 4 to 800K Germanium 0 3K to 100K Carbon Glass 1 4K to 325K Silicon Diode 10uA DC 1 4 to 475K Platinum RTD 1mA DC 14 to 1200K GaAlAs Diode 10uA DC 25K to 325K hermocouple None Option gt 1 4K 55 Cryo con Model 32 Sensor Selection Front Panel or remote interface There are no internal jumpers or switches Sensor Resolution Sensor Dependent See Sensor Performance Data table Sensor Excitation Constant current mode 1mA 100uA or 10pA Constant voltage mode 10mV 3 333mV and 1 0mV RMS Excitation Current 1 0mA to 10nA in steps of 5 of power Resistance Measurement type Ratiometric bridge Resistance Range Constant voltage Maximum resistance 10mV 1MO 3 3mV 430KQ 1 0mV 100KQ AC Excitation Frequency Resistor sensors in constant voltage mode 1 25Hz bipolar square wave Sample Rate 10Hz per channel in all measurement modes Measurement Resolution Sensor Dependent See Sensor Performance Data table Digital Resolution 24 bits Measurement Drift lt 15ppm C Measurement Filter 0 5 1 2 4 8 16 32 and 64 Seconds Calibration Curves Built in curves for industry standard sensors plus four user curves with up to 200 entries each Interpolation is performed using a Cubic Spline CalGen Calibration curve generator fits any diode thermocouple or resistor sensor curve at 1 2 or 3 user specified tempera
67. 50000 25000 00000 75000 50000 255 Cryo con Model 32 S700 Silicon Diode Connections The S700BB is a Silicon Diode temperature sensor Connection is made using a color coded four wire 36 AWG cryogenic ribbon cable Wires may be separated by dipping in Isopropyl Alcohol and 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 700 Cable Color Codes V Clear V Green I Black l Red Table 39 S700 Cable Color Codes S700 Mounting The S700BB bobbin 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 Apiezon 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 256 Cryo con Model 32 INDEX IDN 154 221 OPC 154 221 AC power 17 22 82 connection 75 cord 8 82 83 frequency 5 44 46 95 96 164 fuses 76 low voltage 246 noise 102 power entry module 111 requirements 59 smart on off 18 Voltage Selection 76 Adding a new sensor 86 alarm audible 74 182 224 clearing 30 conditi
68. 833 8547 8753 8977 9198 9373 9542 9768 9865 9950 1 0050 1 0144 1 0241 1 0325 1 0420 1 0506 1 0587 1 0673 1 0753 1 0842 1 0870 1 0904 1 0941 1 0974 1 1011 1 1054 1 1108 L41238 1 1650 1 2070 1 2290 0 WAN OO Temp K 260 250 240 230 220 210 200 190 180 170 160 150 140 130 120 110 100 95 90 85 80 00000 75 70 65 60 55 50 45 40 38 36 34 32 30 28 26 24 22s 20 19 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 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 L13 Volts L25100 1 2720 1 2950 1 3280 1 3650 1 4150 1 4700 1 5270 1 5750 1 5990 1 6230 1 6540 1 6670 1 6840 1 7080 1 7310 1 7500 1 7690 1 7850 1 7970 1 8000 1 8090 1 8160 1 8210 1 8270 1 8340 1 8390 1 8460 1 8520 1 8560 1 8590 1 8630 1 8660 PRPFNHONNNWWWWH FKP HOOD O ON HH 2 00 Ww OOrRrNW BA UD 1 Temp K 00000 00000 00000 00000 00000 00000 00000 00000 00000 50000 00000 50000 00000 50000 00000 50000 00000 50000 00000 75000 50000 25000 00000 75000 50000 25000 00000 75000
69. ASCII command language that is commonly used to program laboratory instruments 74 Cryo con Model 32 Rear Panel Connections The rear panel of the Model 32 is shown here Cryogenic Control Systems Inc Model 32 32B Temperature Controller f y pol aa IEEE 488 2 Madein USA O O 1120 Q RS 232 Input B o O E Loop 2 Loop 1 I l Hi Lo Input A Al CE Figure 3 Model 32 Rear Panel Layout AC Power Connection The Model 32 requires single phase AC power of 50 to 60 Hz 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 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 75 Cryo con Model 32 Fuse Replacement and Voltage Selection Access to the Model 32 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 connect
70. C Power Cord 4038 036 Loop 1 Loop 2 connector kit 4038 033 Din 5 Sensor Input Connector 3038 029 Additional User s Manual CD Table 1 Model 32 Instrument Accessories Cryo con Model 32 Cryogenic Accessories Cryo con ee Part Description S700 S700 series Silicon Diode Temperature Sensors Temperature range 1 4 to 495K CP 100 CP 100 series Ceramic Wound RTD 100Q GP 100 GP 100 series Glass Wound RTD 1000 CPX 100 CPX 100 series Thin Film Platinum RTD 100Q CPX 1K CPX 1K series Thin Film Platinum RTD 1 000Q Cartridge Heater Silicon free 250 25 Watt 3039045 414 x 1 1 8 Temperature range to 1 600K Cartridge Heater Silicon free 500 50 Watt SODIO 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 Pre cut Nichrome wire heater w connectors Custom 4039 013 Specify length or resistance Bulk Nichrome Heater Wire 32AWG 3039 006 Polyamide insulation 100 Table 2 Cryogenic Accessories Cryo con Model 32 Returning Equipment If an instrument 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 2
71. Chrome Aluminum T Blue Copper Constantan U White Copper Copper Table 29 Thermocouple Types Loop 1 Heater Connections Rear panel Primary Heater Output Loop 1 connections are made using the two pin banana plug shown here Pin One of this block HI is the positive output and Pin Two Lo is the ground return The shield of the output cable u should be connected to the third uninsulated TJ O O e banana plug Fans Hi Lo NOLLA W Les oop 2 Loop 1 Loop 2 Output Connections Rear panel connections to the Loop 2 output are made using the two pin pluggable 0 200 terminal block shown above Pin One of this block left hand pin is the positive output and Pin Two is the return The shield of the output cable may be connected to Pin Two The two pin heater terminal block plug is an Augat part number 2ESDV 02 It is available from Cryo con as part number 04 0301 IEEE 488 2 Connections Rear panel connection to the IEEE 488 2 is performed using the GPIB connector GPIB cables are available in various lengths However only shielded type assemblies should be used Many of the molded GPIB cables are actually unshielded and can introduce excessive noise into your instrumentation environment RS 232 Connections The Model 32 uses a Female DB 9 connector for RS 232 serial communications The pin out of this connector is as follows 80 Cryo con Model 32 Pin Function Table 30 RS 232
72. Cryo con Model 32 OVERTEMP commands These commands are associated with the heater s Over Temperature Disconnect feature This feature is used to disconnect the heater if a specified temperature is exceeded on a selected input channel OVERTEMP ENABLE OTD Enable Sets and queries the over temperature disconnect enable Command Syntax OVERTEMP ENABLE lt enab gt Where lt enab gt is the desired enable status which may be ON or OFF Query Syntax OVERTEMP ENABLE Query Response lt enab gt Where lt enab gt is the status of the over temperature disconnect enable Command Example OVERTEMP ENABLE OFF Sets the over temperature disconnect feature to OFF Query Example OVERTEMP ENABLE Example Response YES Indicating that the over temperature disconnect feature is enabled Short Form OVER ENAB 198 Cryo con Model 32 OVERTEMP SOURCE OTD Source Input Channel Sets and queries the input channel that is used as the source for the Over Temperature Disconnect feature Command Syntax OVERTEMP SOURCE lt chan gt Where lt chan gt is the designator of the controlling input channel Query Syntax OVERTEMP SOURCE Query Response lt chan gt Where lt chan gt is the designator of the input channel Command Example OVER SOUR A Sets the over temperature disconnect to monitor channel ChA Query Example OVERTEMP SOURCE Example Response CHB Which indicates that the over temperature disconnect is set
73. DB 9 Connector Pinout The cable used to connect the Model 32 to a computer serial port is a Dual Female Null Modem cable An example is Digikey Inc part number AE1033 ND The wiring diagram for this cable is shown below Note that communication with the Model 32 only requires connection of pins 2 3 and 5 All other connections are optional A id Model 34 PC Dep 1 1 pcp a 5 TX 3 3 Tx DTR 4 4 DTR GND A 5 GND DSR 6 6 DSR cei cts 8 8 cTs RI Y A RI DB9 DB9 DB9 DB9 Male Female Female Male Figure 7 RS 232 Null Modem Cable Mechanical Form Factors and Environmental Display The display is a two line by twenty character dot matrix VFD 81 Cryo con Model 32 Enclosure The Model 32 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 AC Power The Model 34 requires single phase AC power of 50 to 60 Hz Voltages are set by the line voltage selector in the Power Entry Module on the rear panel Line voltage selections are 100 120 220 or 240VAC Tolerance on voltages is 10 to 5 for specified accuracy and 10 for reduced full s
74. ELAYS FAULT Sets or queries the sensor fault enable for the specified relay Sensor Setup Commands CALDATA Sets or queries the name string for a user installed CALDATA NAME sensor CALDATA NAME CALDATA TYPE Sets or queries the sensor type for a user installed CALDATA TYPE sensor CALDATA MULTIPLY Sets or queries the Multiplier for a user installed sensor CALDATA MULTIPLY SENTYPE Queries the name string for a factory installed sensor SENTYPE NAME Please refer to Appendix A SENTYPE NAME 228 Cryo con Model 32 Command Function Autotune Commands AUTOTUNE DELTAP AUTOTUNE DELTAP Sets and queries the maximum allowed change in heater output power that is allowed during the process modeling phase of the autotuning process AUTOTUNE TIMEOUT AUTOTUNE TIMEOUT Sets and queries the timeout value of the autotune process AUTOTUNE START Initiates the autotune sequence AUTOTUNE EXIT Aborts and exits the autotune process AUTOTUNE SAVE When an autotune sequence has successfully completed this command will save the generated PID values to the control loop PID values and change the autotune state from complete to idle AUTOTUNE PGAIN Query the generated P gain term generated by autotune AUTOTUNE IGAIN Query the generated gain term generated by autotune AUTOTUNE DGAIN Query the generated D gain term generate
75. ENABLE Sets and queries the over temperature disconnect enable OVERTEMP SOURCE Sets and queries the input channel that is used as the OVERTEMP SOURCE source for the Over Temperature Disconnect feature OVERTEMP TEMP Sets and queries the temperature used by the over OVERTEMP TEMP temperature disconnect feature Sensor Calibration Curve Commands CALCUR Sets or queries sensor calibration curve data CALCUR PID Table Commands PIDTABLE Queries the name string of a PID table at a specified PIDTABLE index PIDTABLE NENTRY PIDTABLE NENTRY Queries the number of entries in a PID Table PIDTABLE TABLE PIDTABLE TABLE Sets or queries the entries in a PID table 227 Cryo con Model 32 Command Function Relay Commands Model 34 and 62 only RELAYS Relay Status Query RELAYS SOURCE RELAYS SOURCE Sets or queries the source input channel for a specified relay RELAYS HIGHEST RELAYS HIGHEST Sets or queries the temperature setting of the high temperature setpoint for the specified relay RELAYS LOWEST RELAYS LOWEST Sets or queries the temperature setting of the low temperature setpoint for a specified relay RELAYS HIENA RELAYS HIENA Sets or queries the high temperature enable for the specified relay RELAYS LOENA RELAYS LOENA Sets or queries the low temperature enable for the specified relay RELAYS FAULT R
76. Example CALDATA 3 NAME Example Response User Curve 2 Short Form CALD SENT NAME Name for a factory installed sensor Queries the name of a factory installed sensor Query Syntax SENT lt index gt NAME Or SENT lt index gt Query Response lt name gt Where lt index gt is the index of the factory installed sensor and lt name gt is the name string for the indexed sensor Query Example SENT 1 Example Response Cryocon S700 Short Form SENT 207 Cryo con Model 32 CALDATA TYPE Sensor Type Sets or queries the sensor type at a Sensor Table index Supported sensor types are described above in the Supported Sensors section Command Syntax CALDATA lt index gt TYPE lt stype gt Where lt index gt is the index to the user installed sensor and lt stype gt the sensor type selected from the above list Query Syntax CALDATA lt index gt TYPE Query Response lt stype gt Where lt index gt is the index and lt stype gt is the sensor type Command Example SENT 3 TYPE DIODE This command assigns the Silicon Diode sensor type to the user installed sensor at index 3 Query Example CALDATA 1 TYPE Example Response TC80 This response indicates that the sensor at index 1 is a thermocouple Short Form CALD TYP 208 Cryo con Model 32 CALDATA MULTIPLY Calibration Curve Multiplier Sets or queries the Multiplier field for a user installed sensor The multiplier f
77. INPUT SLOPE Slope of best fit straight line 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 STATS RESET command was issued SLOPE is in degrees per Minute Query Syntax INPUT lt channel gt SLOPE Where lt channel gt is the input channel indicator Query Response lt temp gt Where lt temp gt is the temperature slope Query Example INP B SLOPE Example Response 1 2323 Short Form INP lt channel gt SLOP 184 Cryo con Model 32 INPUT OFFSET Offset of best fit straight line Queries the input channel statistics OFFSET is the offset of the best fit straight line passing through all temperature samples that have been collected since the STATS RESET command was issued OFFSET is in degrees Query Syntax INPUT lt channel gt OFFSET Where lt channel gt is the input channel indicator Query Response lt temp gt Where lt temp gt is the temperature offset Query Example INP B OFFSET Example Response 124 25 Short Form INP lt channel gt OFFS 185 Cryo con Model 32 LOOP commands Loop commands are used to configure and monitor Model 32 s control loops Note LOOP 1 may also be referred to as HEATER and LOOP 2 may be referred to as LOOP 2 Loop 1 is the controller s primary heater output channel In the Model 32 and 32B this is a 50 25 Watt three range linear
78. 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 The logical AND of the ESR and ESE registers sets the Standard Event register in the Status Byte STB 150 Cryo con Model 32 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 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 RQS SE MAV IE 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
79. Load 100 in 250 setting 400 in 500 setting Digital Resolution 1 0PPM of full scale corresponding to 20 bits Readback Heater output power Heatsink temperature Loop 2 Output Standard Model 32 Type Voltage output Oto 10 Volts Input impedance 5000 Connection Two pin 3 5mm detachable terminal block Digital Resolution 1 0PPM of full scale corresponding to 20 bits Loop 2 Heater Output Model 32B 57 Cryo con Model 32 Type 10 Watt short circuit protected linear current source Maximum output is 0 4A at 25V Load Resistance 62 50 10Watts 500 8Watts 250 4 Watts or 100 1 6 Watts Digital Resolution 1 0PPM of full scale corresponding to 20 bits Readback Heater output power 58 Cryo con Model 32 Status Outputs Audible and Visual Alarms Independent audible and visual alarms Status reported via Remote Interface Sensor fault Heater over temperature fault Remote Interfaces Remote interfaces are electrically isolated to prevent ground loops RS 232 Serial port is an RS 232 standard null modem Rates are 300 1200 4800 9600 19 200 and 38 400 Baud IEEE 488 GPIB Full IEEE 488 2 compliant Language Remote interface language is IEEE SCPI compliant National Instruments LabVIEW drivers available for all interfaces User Setups Two User Setups are available that save and restore the complete configuration of the instrument Firmware Internal firmware and all data tables ar
80. MaxSet gt Where lt no gt is the loop number and lt MaxSet gt is the desired maximum set point Query Syntax LOOP lt no gt MAXSET Query Response lt MaxSet gt Command Example LOOP 1 MAXSET 300 Sets the maximum allowed setpoint on Loop 1 to 300 Query Example LOOP 1 MAXSET Example Response 250 Short Form LOOP MAXS 196 Cryo con Model 32 LOOP PMANUAL Control Loop Manual Power Output Setting Sets and queries the output power level used by the selected control loop feedback when it is in Manual control mode This value may be changed at any time but is only used during Manual operation PMANUAL is a numeric field that is a percent of full scale selected control loop output current Actual selected control loop output power will depend on the selected control loop range setting Command Syntax LOOP lt no gt PMANUAL lt value gt Where lt no gt is the loop number 1 or 2 and lt value gt is the desired selected control loop output current as a percent of full scale Query Syntax LOOP lt no gt PMANUAL Query Response lt value gt Where lt value gt is the desired output power as a percent of full scale Command Example LOOP 1 PMAN 50 Sets the control loop 1 s output power to 50 of full scale when the loop is in manual control mode Query Example LOOP 1 PMAN Example Response 25 000 Indicates that loop 1 has a manual output power setting of 25 Short Form LOOP PMAN 197
81. Menus 37 Cryo con Model 32 Setpoint Numeric Entry The first line of this menu 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 c 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 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 in percent of full scale output power Watts and may have values from zero to 100
82. Number of Pts 101 Sensor Name is any 15 character string and is only used to identify the sensor Sensor type can be selected from a pull down menu or entered directly Note that different models of Cryo con instruments support different types of sensors Therefore it is important to enter a sensor type that is supported by the specific product If the instrument receives a sensor type that it does not support the Diode type is selected The section titled Supported Sensor Configurations gives complete information on sensor types The Multiplier field is used to select the sign of the sensor s temperature coefficient A value of 1 selects a Negative Temperature Coefficient sensor while a value of 1 selects a Positive Temperature Coefficient The Unit field selects the units used in the calibration curve Choices are Volts Ohms or LogOhm Checking the Save as crv will save the curve to disk as a Cryo con crv file 119 Cryo con Model 32 The sensor curve may be viewed as a graph by clicking the Display Curve button A NL A UNI IA mn Wi An example plot is shown here After completing any desired changes in the Edit Curve Header dialog box click Accept to proceed Then the curve number dialog box will appear A user calibration curve should be entered here For the Model 32 user curves are 1 through 4 For the Model 34 and Model 62 user curves
83. OGOHM Each entry of a curve contains a sensor reading and the corresponding temperature Sensor readings are in units specified by the units of the curve using the CALDATA UNITS command These units may be OHMS VOLTS or LOGOHM 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 white spaces NOTE Using the RS 232 interface each line must be terminated by a New Line a Carriage Return a Line Feed or a Null character This character is not used with the GPIB interface since the end of a line is signaled by the interface itself Here lines are transmitted to the controller by using sequential write commands Floating point numbers may be entered with many significant digits They will be converted to 32 bit floating point This supports about six significant digits The last entry of a table is indicated by a semicolon character with no values in the numeric fields NOTE All curves must have a minimum of two entries and a maximum of 200 entries Entries may be sent to the controller in any order The unit will sort the curve in ascending order of sensor reading before it is copied to Flash RAM 200 Cryo con Model 32 Entries containing invalid numeric fields will be deleted before they are stored
84. PC command 154 Operate Display 24 OTD 45 enable 43 setpoint 44 source 43 OTDisconn 27 output power limit 40 Over Temperature Disconnect 27 45 Overtemp 27 OVERTEMP commands 198 PID Cryo con Model 32 coefficient 48 210 configuration 38 control 73 188 loop 73 mode 71 Table 40 48 71 73 115 122 188 189 203 205 206 227 Table index selection 40 zone 48 PID Table File Format 203 PIDTABLE commands 203 POWER key 11 proportional gain 38 192 226 Protective Ground 75 Ramping 93 Algorithm 94 operation 93 rate selection 41 Setup 94 Ratiometric 60 Readback 27 Real Time Monitor 122 Remote LED 23 157 remote transactions viewing 47 RS 232 46 74 160 connection 81 RST command 154 Index 4 S700 9 255 Color Codes 256 mounting 256 SCPI 74 command header 148 common command 147 152 compound command 147 keyword truncation 148 simple command 147 sensor calibration curve 200 connection 55 69 70 77 79 237 self heating 60 61 setup 51 table index 51 type 208 228 type selection 34 51 units 34 171 Sensor Calibration Curve 118 121 202 227 file format 200 Sensor Setup Menu 207 SensorFlt 27 Single Point Ground 111 112 113 Standard Event Register 150 Standard Event Status Enable 153 221 STATS commands 169 STB 149 150 151 Cryo con Model 32 STOP command 155 157 STOP key 11 Supported Sensors 55 Synchrono
85. Sets or queries the control loop 1 or the primary heater output range LOOP TABLEIX Sets or queries the table number that is used with control LOOP TABLEIX modes that use PID tables LOOP RAMP Queries the unit to determine if a temperature ramp is in progress on the specified control loop LOOP RATE Sets and queries the ramp rate used by the selected control LOOP RATE loop when performing a temperature ramp LOOP NAME Sets or queries the name string for the selected control loop LOOP NAME LOOP PGAIN Sets or queries the selected control loop s proportional gain LOOP PGAIN term LOOP IGAIN Sets and queries the integrator feedback term used by the LOOP IGAIN selected control loop LOOP DGAIN Sets and queries the differentiator feedback term used by the LOOP DGAIN selected control loop LOOP HTRREAD Queries the output current of the selected control loop LOOP MAXPWR LOOP MAXPWR Sets and queries the maximum allowed output power LOOP MAXSET Sets and queries the maximum setpoint LOOP MAXSET LOOP 1 LOAD Sets or queries the load resistance setting of the primary LOOP 1 LOAD heater Loop 1 LOOP PMANUAL LOOP PMANUAL Sets and queries the output power level used by the selected control loop feedback when it is in Manual control mode 226 Cryo con Model 32 Command Function Over Temperature Disconnect Commands OVERTEMP ENABLE OVERTEMP
86. Setup Menu Pressing the Sensor key from the Home Status Display accesses the Sensor Setup Menu Definition of a sensor requires entering configuration data on this screen followed by entering a calibration curve The first three lines of the Sensor Setup Menu show the Sensor Index followed by a greater than gt character This gt character indicates the first level of the Sensor Setup menu Sensor Setup Menu Sets the Sensor Index Scroll through 1 18 gt User Sensor 4 Ki choices until the desired sensor is displayed and press Enter Sets the Sensor Type which includes a voltage range and excitation Selections 2 18 gt Type Diode M are described in the Sensor Type table above Sets the sensor Temperature 3 18 gt Mult 1 0 Coefficient and Calibration Curve Multiplier y Sets Units of the sensor s Calibration 4 18 gt Units Volts hq Curve Choices are Ohms Volts and LogOhm Pressing Enter will display the next level 5 18 gt Edit Cal Curve M menu where the sensor s Calibration Curve data may be viewed and edited Table 15 Sensor Setup Menu The first line on this menu is the sensor table index Selecting this field will allow scrolling 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 I O interfaces but may not b
87. T Input Channel Temperature Query 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 Syntax INPUT lt channel gt Where lt channel gt is the input channel parameter Query Response lt temp gt Where lt temp gt is the temperature of the specified input channel in display units K F C or S Floating Point string Query Example INPUT B Example Response 123 4567 Alternate Form INPUT lt channel gt TEMP Short Form INP 170 Cryo con Model 32 INPUT TEMPER Input Temperature The INPUT TEMPER query is identical to the input query described above It 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 Syntax INPUT lt channel gt TEMPER Where lt channel gt is the input channel parameter Query Response lt temp gt Where lt temp gt is the temperature of the specified input channel in display units K F C or S Floating Point string Query Example INP B TEMP Example Response 12 45933 Short Form INP lt channel gt TEMP INPUT UNITS Input channel units Sets or reports the display units of temperature used by the specified input channel Command Syntax INPUT lt channel gt UNITS lt units gt Where lt channel gt is the input channel
88. The following is an example of a calibration curve transmitted to the controller via the GPIB interface CALCUR 1 Good Diode Diode 1 0 volts 0 34295 0 32042 0 35832 1 20000 1 05150 0 53234 300 1205 273 1512 315 0000 3 150231 8 162345 460 1436 The controller would sort the above table in ascending order of volts then write it to FLASH memory as user curve 1 The curve name will be Good Diode and the native units are volts When a complete curve is received it is conditioned sorted and copied to FLASH memory This process can take as long as 250 milliseconds with a long table c Note When using the RS 232 interface a time delay should of about 500mS should be inserted after sending the last line of a calibration table This will allow the flash memory update to complete Other remote interfaces do not require a delay gt Note Factory installed calibration curves may not be changed or deleted with these commands 201 Cryo con Model 32 CALCUR Calibration Curve Set or Query Sets or queries sensor calibration curve data Command Syntax CALCUR lt index gt lt sensor name gt lt sensor type gt lt multiplier gt lt curve units gt lt sensor reading 1 gt lt Temperature 1 gt lt sensor reading 2 gt lt Temperature 2 gt o lt sensor reading N gt lt Temperature N gt c Note A new line In character must be appended to each line when using the RS 232 serial por
89. User s Guide Model 32 8 32B 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 O Copyright 2008 Cryogenic Control Systems Inc All Rights Reserved Printing History Edition 6e March 2008 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
90. X lt ix gt Where lt channel gt is the input channel parameter and lt ix gt is the desired sensor index Query Syntax INPUT lt channel gt USENIX Where lt channel gt is the input channel indicator Query Response lt ix gt Where lt ix gt is the sensor index for the selected input channel If the index is outside of the range 0 through 3 a value of 1 will be returned Command Example INPUT B USENIX 0 This command sets the sensor index for input channel B to zero disabled Query Example INP A USENIX Example Response 2 This indicates that sensor 02 is assigned to input channel A Short Form INP SEN 174 Cryo con Model 32 INPUT SENIX Sensor index obsolete Sets or queries the sensor index number assigned to an input channel This command is used to assign the sensor type to a channel Sensor types and configurations are accessed using the SENTYPE commands Sensor index zero indicates that there is no sensor connected to the selected input channel This will disable all readings on the channel Refer to Appendix A for a description of sensors indices etc Note To ensure portability of software written for the Model 32 you should use the ISENIX command to assign a factory installed sensor or USENIX to assign a user sensor This way the index will always correspond to the correct sensor regardless of the Model 32 firmware revision Command Syntax INPUT lt channel gt SENIX lt ix gt
91. X or ISENIX commands INPUT SENIX described above Sets or queries the sensor index number assigned to an input channel INPUT VBIAS Set or query the sensor voltage excitation used in the INPUT VBIAS constant voltage mode Applies to constant voltage mode sensors only INPUT NAME Sets or queries the name string of the specified input INPUT NAME channel INPUT ALARM Queries the alarm status of the specified input channel INPUT ALARM HIGHEST INPUT ALARM HIGHEST Sets or queries the temperature setting of the high temperature alarm for the specified input channel INPUT ALARM LOWEST INPUT ALARM LOWEST Sets or queries the temperature setting of the low temperature alarm for the specified input channel INPUT ALARM HIENA INPUT ALARM HIENA Sets or queries the high temperature alarm enable for the specified input channel INPUT ALARM LOENA INPUT ALARM LOENA Sets or queries the low temperature alarm enable for the specified input channel INPUT ALARM FAULT INPUT ALARM FAULT Sets or queries the sensor fault alarm enable for the specified input channel INPUT ALARM AUDIO INPUT ALARM AUDIO Set or query the audible alarm enable for the selected input channel 224 Cryo con Model 32 Command Function Input Channel Commands INPUT SENPR Queries an input channel reading in basic sensor units Sensor units are Volts for diode and thermocouple sensors and Ohm
92. ait for the process to complete Press the Abort button to terminate the process When the capture is complete dismiss the following dialog Cryo con Utility Softwa fe 9 Captured Upper Yalue Line 3 requires setting a lower target value on the input channel Depending on the calibration range selected this will be in Volts or Ohms First establish a voltage or resistance on the selected input channel that is near the recommended value Then enter the actual value in the box provided 139 Cryo con Model 32 4 Click the Capture button on Line 4 The software will wait for the reading to stabilize and then will capture the reading and display it in the edit box on Line 4 When the above procedure is complete you will have established upper and lower target values as well as upper and lower measurements The edit boxes on lines 2 and 4 will contain the measured values At this time you may still change the target values on line 1 and 3 if desired Now you can automatically compute the required gain and offset values by clicking on the Calibrate button in the Calibration Results box This will change the Status field from Current to Calibrated and will update the Offset and Gain values with those calculated At this point to values have been transmitted to the instrument In order to send the offset and gain values to the instrument s calibration memory click the APPLY button You will be requir
93. alibration of the 10uA current source Note that the voltage calibration must always be done first since the current source calibration requires a precision voltage reading Diode Voltage Calibration To calibrate the diode voltage range click on the SI Diode V tab and follow the sequence described above to send Gain and Offset values to the instrument The upper target requires connection of a 1 9 Volt source The actual value is between 1 0 Volts and 2 4 Volts If you do not have a precision voltage source you can use a 1 5 Volt battery by using a high precision volt meter to measure it s actual voltage The lower target requires connection of a 0 5 Volt source The actual value is between zero Volts and 0 6 Volts If you do not have a precision voltage source you can short the input channel for zero volts Constant current Source Calibration Calibration of the constant current source is performed by using the SI Diode tab On this screen only an upper target value is required since the current source only requires a gain term The upper target requires connection of a 100KO resistor The actual value should be within 10 of 100KQ 142 Cryo con Model 32 Calibration of DC resistors Resistor sensors that use direct current excitation are calibrated by using the 1mA DC 100uA DC and 10uA DC tabs Resistors required for calibration are as follows a 1mA DC Upper 1000 Lower 100 a 100uA DC Upper 1 000 Q Lower
94. anual PN 3038 029 a Cryo con software CD PN 4034 029 Q Connector kit PN 4038 015 consisting of Two DIN 5 input connectors PN 04 0436 A Dual banana plug heater connector PN 04 0433 A Terminal block plug Loop 2 connector PN 04 0301 Detachable 120VAC Line Cord 04 0310 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 220 VAC setting On the rear panel of the instrument the AC voltage selection can be seen on the power entry module If the setting is incorrect please refer to section Fuse Replacement and Voltage Selection to change it Apply Power to the Controller Connect the power cord and turn the controller on by pressing the Power key for a minimum of 0 5 Seconds The front panel will show a Power Up display with the model number and firmware revision Cryo con Model 32B While the Power Up display is shown the controller is performinga Firmware Rev 6 04H self test procedure that verifies the proper function of internal 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 the un
95. ase the n OxA character should be selected 146 Cryo con Model 32 Introduction to Remote Programming Instructions Instructions both commands and queries normally appear as a string embedded in a statement of your host language such as BASIC or C Instructions are composed of two main parts The header which specifies the command or query to be sent and the parameters which provide additional data needed to clarify the meaning of the instruction An instruction header is comprised of one or more keywords separated by colons Queries are indicated by adding a question mark to the end of the header Many instructions can be used as either commands or queries depending on whether or not you have included the question mark The command and query forms of an instruction usually have different parameters Many queries do not use any parameters The white space is used to separate the instruction header from the instruction parameters If the instruction does not use any parameters you do not need to include any white space White space is defined as one or more spaces ASCII defines a space to be character 32 in decimal Instruction parameters are used to clarify the meaning of the command or query They provide necessary data such as whether a function should be on or off which input channel controls the heater output etc Each instruction s syntax definition shows the parameters as well as the values they acce
96. asserted for input channel A Short Form INP lt channel gt ALAR 176 Cryo con Model 32 INPUT ALARM HIGHEST Alarm High Setpoint 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 will be asserted Temperature is assumed to be in the display units of the selected input channel There is a 0 25K hysteresis in the assertion of a high or low temperature alarm condition Command Syntax INPUT lt channel gt ALARM HIGHEST lt temp gt Where lt channel gt is the input channel indicator and lt temp gt is the alarm setpoint temperature Temperature is a floating point string that may be up to 20 characters Query Syntax INPUT lt channel gt ALARM HIGHEST Query Response lt temp gt Where lt channel gt is the input channel indicator and lt temp gt is the temperature setting of the high temperature alarm for lt channel gt Temperature is reported to the full precision of 32 bit floating point Command Example INP A ALARM HIGH 200 5 Sets the high temperature alarm setpoint for input channel A to 200 5 Query Example INP A ALARM HIGHEST Example Response 125 4321 If the display units setting for input channel A are Kelvin this response is also in units of Kelvin Short Form INP lt channel gt ALAR HIGH 177 Cryo con Model 32 INPUT ALARM LOWEST Alarm Low Setpoi
97. asurements 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 Model 32 utilities software Input Channel 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 Thermal EMF and AC Bias Issues DC offsets can build up in cryogenic temperature measurement systems due to Thermocouple effects within the sensor wiring Careful wiring can minimize these effects However in a few systems measurement errors induced by thermal EMFs ca
98. ation Sensor type ACR indicates an AC resistor sensor that uses constant voltage bias Here the Bias Voltage field will show selections of 10 0mV 3 3mV and 1 0mV to 35 Cryo con Model 32 indicate the voltage that is held on the sensor The Model 32 has an autoranging current source that will maintain the selected voltage For sensor types other than ACR the Bias Voltage field will show N A for not applicable Additional information on excitation voltages and currents is given in the section Input Channels The Control Loop Setup Menu The control loop setup menus are selected by pressing the Loop 1 or Loop 2 key from a Home Status Display These menus contain all of the user configurable parameters for the selected control loop The Loop 1 menu is used to perform the setup of the primary 25 50 Watt heater output This display was designed to provide all of the information required to tune heater parameters and is therefore rather complex The Loop 2 menu is used to perform the setup of the secondary output For a standard Model 32 this is a zero to 10 Volt output For a Model 32B this is a 10 Watt current source The first character on each line of the control loop setup menu is always the loop identifier which is a superscripted 1 or 2 for Loop 1 or Loop 2 36 Cryo con Model 32 Loop 1 Loop 2 Setup Menu 1 77 123K 5 79 000K Numeric setpoint en
99. ation that was 3 never saved Config restored When a configuration is successfully restored the display shown here is shown After a one or two seconds the controller will automatically perform a power up reset with the restored data 42 Cryo con Model 32 The System Functions Menu This menu is accessed by pressing the Sys key from the Home Status Display It is used to set many of the instrument s parameters including display resolution I O port settings etc System Functions Menu Sets the display time constant in 1 SYS Display TC 2 0SH seconds Selections range from 0 58 to 64S S h lution Selecti 21 2 2 SYS Di spl ay RS Ful 1 H a tion Selections are Enables or disables Cold Junction A Compensation for Thermocouple 3 SYS CJ Comp Ena ONN sensors Only shown when the thermocouple option is present Offset in C applied to thermocouple 4 SYS CJoffset 0 00 Cold Junction Compensation Only shown when the thermocouple option is present 2 Display brightness Selections are 0 1 2 5 SYS Brightness ON ci 6 OTD Enable Off N Sets the Over Temperature Disconnect enable Selections are On or Off Sets the Over Temperature Disconnect 7 OTD Source ChAN source input channel Selections are ChA or ChB 43 Cryo con Model 32 System Functions Menu cont A Sets the Over Temperature Di
100. atus gt Where lt status gt is the setting of the low temperature alarm enable for lt channel gt lt status gt will be either YES or NO Command Example INPUT A ALARM LOENA YES Enables the low temperature alarm for input channel A Query Example INP B ALARM LOEN Example Response NO Query Example INP B ALARM HIENA LOENA Example Response YES NO The high temperature alarm enable for input channel B is reported followed by the low temperature alarm enable Short Form INP lt channel gt ALAR LOEN 180 Cryo con Model 32 INPUT ALARM FAULT Alarm on Sensor Fault Sets or queries the sensor fault alarm enable for the specified input channel An alarm must be enabled before it can be asserted Command Syntax INPUT lt channel gt ALARM FAULT lt status gt Where lt channel gt is the input channel indicator and lt status gt is the status of the sensor fault alarm enable lt status gt may be either YES or NO Query Syntax INPUT lt channel gt ALARM FAULT Where lt channel gt is the input channel indicator Query Response lt status gt Where lt status gt is the setting of the sensor fault alarm enable for lt channel gt lt status gt will be either YES or NO Command Example INPUT A ALARM FAULT YES Enables the sensor fault alarm for input channel A Query Example INP B ALARM FAULT Example Response NO Indicating that the sensor fault alarm enable for channel B is disabled Query Example
101. ause the fourth character is a vowel 182 Cryo con Model 32 INPUT MINIMUM Statistical Minimum Queries the minimum temperature that has occurred on an input channel since the STATS RESET command was issued Query Syntax INPUT lt channel gt MINIMUM Where lt channel gt is the input channel indicator Query Response lt temp gt Where lt temp gt is the minimum temperature Query Example INP B MIN Example Response 90 2322 Short Form INP lt channel gt MIN INPUT MAXIMUM MAXIMUM Statistical Maximum Queries the Maximum temperature that has occurred on an input channel since the STATS RESET command was issued Query Syntax INPUT lt channel gt MAXIMUM Where lt channel gt is the input channel indicator Query Response lt temp gt Where lt temp gt is the maximum temperature Query Example INP B MAX Example Response 90 2322 Short Form INP lt channel gt MAX 183 Cryo con Model 32 INPUT VARIANCE Statistical Variance Queries the temperature variance that has occurred on an input channel since the STATS RESET command was issued Variance is calculated as the Standard Deviation squared Query Syntax INPUT lt channel gt VARIANCE Where lt channel gt is the input channel indicator Query Response lt temp gt Where lt temp gt is the statistical variance of temperature Query Example INP B VAR Example Response 1 2223 Short Form INP lt channel gt VAR
102. autotune capability Once the information is placed into a PID Table the Model 32 will control in Table mode by interpolating optimum PID values based on setpoint The Model 32 allows for the entry of four independent PID Tables Each table may contain up to 16 temperature zones In the Ramp control mode the controller will approach a new setpoint at a user specified rate When this setpoint is reached the controller will revert to PID control 73 Cryo con Model 32 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 There is a 0 25K hysteresis built into the high and low temperature alarms Remote Interfaces IEEE 488 2 and RS 232 interfaces are standard All functions and read outs available from the instrument may be completely controlled by any of these interfaces The Serial port is an RS 232 standard null modem with male DB9 connector Rates are 300 1200 4800 9600 19 200 and 38 400 Baud The GPIB is fully IEEE 488 2 compliant Connection is made at the rear panel using the IEEE 488 standard connector The programming language used by the Model 32 is identical for all interfaces and is SCPI language compliant The Standard Command Protocol for programmable Instruments SCPI is a sub section of the IEEE 488 2 standard and is a tree structured
103. c Note The input connectors on the Model 32 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 Red Sense Black senseo 2 Table 28 Dual Sensor Cable Color Codes 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 DIN 5 s 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 Four VVire Resistor Sensor Four Wire Diode Sensor Figure 5 Diode and Resistor Sensor Connections 78 Cryo con Model 32 Cryo con S700 Silicon Diode Connections The S700BB is a Silicon Diode temperature sensor Connection is made using a color coded four wire 36 AWG cryogenic ribbon cable Wires may be separated by dipping in Isopropyl Alcohol and then wiping clean Insulation is Formvar and is difficult to strip Techniques include u
104. cale Query Syntax lt oc gt AUTOTUNE DELTAP Query Response lt value gt Where lt oc gt is the output channel to tune and may be either LOOP 1 or LOOP 2 lt value gt is the current Delta Power setting Command Example LOOP 1 AUTOTUNE DELTAP 100 This sets the maximum change in output power to 100 of full scale This will allow the tuning process to use any output level Query Example LOOP 2 AUTOTUNE DELTAP Example Response 25 0000 This response says that the maximum change in output power used by autotune will be 25 of the current output power level Short Form AUT DELT 211 Cryo con Model 32 AUTOTUNE TIMEOUT Autotune Timeout Sets and queries the timeout value of the autotune process This is a numeric field that specifies the maximum time in seconds that the autotune process model will wait for it s internal error vector to converge without declaring a timeout condition Command Syntax lt oc gt AUTOTUNE TIMEOUT lt value gt Where lt oc gt is the output channel to tune and may be either LOOP 10r LOOP 2 lt value gt is the timeout period in seconds Query Syntax lt oc gt AUTOTUNE TIMEOUT Query Response lt value gt Where lt oc gt is the output channel to tune and may be either LOOP 2or LOOP 2 lt value gt is the timeout period in seconds Command Example LOOP 2 AUTOTUNE TIMEOUT 200 Sets the autotune timeout period to 200 Seconds Query Example LOOP 1 AUTOTUNE TIME Example R
105. cale heater output in the highest output range 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 The power jack and mating plug of the power cable meet Underwriters Laboratories UL and International Electrotechnical Commission IEC safety standards Power requirement is 25 Watts plus the power being provided to the heater load The power cord will be a standard detachable 3 prong type User replaceable fuses are incorporated in the Power Entry Module See the section titled Fuse Replacement Voltage Selection c Note The Model 32 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 Environmental and Safety Concerns Safety The Model 32 protects the operator and surrounding area from electric shock or burn mechanical hazards excessive temperature and spread of fire from the instrument 8
106. calibration curves are 1 One point near 300K The portion of a Diode Sensor curve above 30K will be 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 Two points 300K and 77K Here two user specified points are taken to fit the diode curve region above 30K The entire curve is offset to match the 77K point then the gt 30K region is fit to the two points 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 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 will be displayed that allows the user to select the number of points desired for the CalGen fit First CalGen Menu Diode Sensor 1 E1 pt CalGen 300K MW generation with a single point near Pressing the Enter key will select curve 300K 2 E2 pt CalGen generation at two points where both Pressing the Enter key will select curve points must be gt 50K 3 E 3pt CalGen BW generation three points Two above 50K Pressing the Enter key will select curve and one near 4 2K 4 E1 pt CalGen 4 2K a Pressing the E
107. ce thermocouple sensors should be floating This will ensure that no noise currents can flow in the sensor leads and that no common mode noise voltage will be directly coupled into the controller If a thermocouple must be grounded the ground point should be a good earth ground that has the same potential as the earth ground of the instrument If the ground point is floating or only loosely connected to earth ground significant noise pickup can result Since floating thermocouples will always give the best accuracy they should be electrically insulated by using small Sapphire washers Assuming that a grounded thermocouple is properly connected the controller should operate properly If this is not the case the problem can usually be tracked to the ground connection made at the sensor relative to the ground at controller The ground potential at the thermocouple sensor must fall within the 5 volt input range of the controller Usually the voltage difference between the sensor ground and the controller s ground is an AC power line signal It can be seen with a battery powered AC voltmeter connected between the controller s chassis and a ground point near the sensor If there is a significant voltage difference a safety hazard may be present Building wiring should be tested before proceeding 103 Cryo con Model 32 A voltage difference caused by a loose or non existent ground reference can be corrected by 1 Establish
108. ce to degrade even further In still other systems the thermal signature of the cryocooler will be 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 will 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 there is still the possibility of instability The Model 32 uses 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 will synchronously subtract 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 95 Cryo con Model 32 Synchronous Filter Setup To use the synchronous filter two parameters
109. cified curve Command Example PIDTABLE 1 NAME Ed s table This command will assign the name of Ed s table to PID table located at index number 1 Query Example PIDTABLE 3 NAME Example Response Mary s project Indicates that the PID table at index 3 is named Mary s project Short Form PIDT NAM 205 Cryo con Model 32 PIDTABLE NENTRY Number of Entries Queries the number of entries in a PID Table This number is generated from the table itself and cannot be changed using this command The maximum number of entries in a table is 16 Query Syntax PIDTABLE lt index gt NENTRY Query Response lt number gt Where lt index gt is the index to the PID table list and lt number gt is the number of entries in the indexed table Query Example PIDTABLE 1 NENTRY Example Response 5 Indicates that there are 5 entries in PID table 1 Short Form PIDT NENT PIDTABLE TABLE PID Table Set Query Sets or queries the entries in a PID table Command Syntax PIDTABLE lt index gt TABLE lt name gt lt setpoint gt lt P gt lt I gt lt D gt lt Heater Range gt lt setpoint gt lt P gt lt I gt lt D gt lt Heater Range gt lt setpoint gt lt P gt lt I gt lt D gt lt Heater Range gt o o o lt setpoint gt lt P gt lt I gt lt D gt lt Heater Range gt Where lt index gt is a numeric index of the PID table and lt name gt is the table name 15 characters maximum Table entries are mad
110. con Model 32 LOOP TABLEIX Control loop PID Table number 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 Command Syntax LOOP lt no gt TABLEIX lt number gt Where lt no gt is the loop number 1 or 2 and lt number gt is the loop s control PID table number Query Syntax LOOP lt no gt TABLEIX Query Response lt number gt Where lt number gt is the PID table number Command Example LOOP 1 TABLEIX 5 Sets the loop 1 PID table to table number 5 Query Example LOOP 1 TABLE Example Response 3 Which indicates that the Loop 1 is controlling based on PID Table number 3 Short Form LOOP TYPE 189 Cryo con Model 32 LOOP 1 RANGE Control Loop 1 Output Range Sets or queries the control loop 1 or the primary heater output range Range determines the maximum output power available and is different for a 500 load resistance than for a 25Q load Values of heater range are Hi Mid and Low These correspond to the output power levels shown here Command Syntax LOOP 1 RANGE lt range gt Range 500 Load 250 Load Hi 50W 25W Mid 5W 2 5W Low 0 5W 0 25W Where lt range gt is the desired heater output range from the above list Query Syntax LOOP 1 RANGE Query Response lt range gt Command Example LOOP 1 RANGE LOW Sets the heater power output range to Low
111. cted user location Note The CalGen process may be aborted by pressing the Esc or Home key Using CalGen With Platinum and Thermocouple Sensors The calibration curve generation procedure for Platinum or Thermocouple sensors is the same as for the diode sensors described above However Platinum sensor curves are generated using two user specified points Therefore the selection of the number of points is not required 109 Cryo con Model 32 110 Cryo con Model 32 System Shielding and Grounding Issues Grounding Scheme The grounding scheme used in all of Cryo con s instruments is based on a Single Point Ground and is designed to minimize ground loop and noise pickup by assuming that the Sensor and Heater elements are electrically floating but the remote interfaces are not The Single Point Ground The internal Single Point Ground is the voltage reference point for the instrument s grounding scheme All circuits are designed so that no current will normally flow through the connections to this ground Therefore it provides a good quality low impedance path to ground for any undesired currents that are coupled into the equipment AC Power Entry AC Power enters the instrument directly into a power entry module This provides fusing line voltage selection and RFI filtering The Building Ground often referred to as Earth Ground Shield Ground or Third Wire Gro
112. d by autotune AUTOTUNE STATUS Queries the status of the autotune process Cryocooler Filter Commands Model 34 Only CCFILTER STATUS Query Cryocooler filter status CCFILTER TYPE CCFILTER TYPE Set or query filter type Types are OFF Input or Cancel CCFILTER STEP CCFILTER STEP Set or query the filter adaptation step size CCFILTER LOOP CCFILTER LOOP Set or query the control loop number controlled by the cryocooler filter CCFILTER NTAPS CCFILTER NTAPS Set or query the number of taps in the filter CCFILTER RESET Reset the Cryocooler filter Table 37 Remote Command Summary 229 Cryo con Model 32 230 Cryo con Model 32 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 32 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 equi
113. del more susceptible to corruption by noise 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 will also corrupt the tuning result Worse it may allow application of too much heater power and may cause an over temperature condition Experience indicates that most cryogenic systems will autotune properly using a DeltaP of 10 whereas a noisy system will require 20 or more A common example of a noisy cryogenic system is one where a Silicon Diode sensor is used with a setpoint near room temperature System Noise and Tuning Modes Three modes of autotuning may be selected They are P only PI and PID 88 Cryo con Model 32 Using P only autotuning will result in the maximum value for P that will not cause oscillation The process temperature will stabilize at some point near the setpoint Using Pl or PID control will result 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 PI control should be used with all others Sensor type has a significant impact on measurement noise The Model 32 uses a ratiometric technique to measure r
114. e In the default case this means Kelvin per minute For more information on temperature ramps refer to the section on Temperature Ramping below 41 Cryo con Model 32 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 32 including setpoints heater configurations input channel data etc User Configurations Menu Selects the user configuration The 1 Confi g UserConfi g ON Model 32 has four configurations available Pressing the Enter key saves the 2 Confi g Save a instrument setup to the selected configuration number Pressing the Enter key restores a saved configuration 3 Config Restore a Table 11 User Configurations Menu To save or restore a setup select the desired configuration number on line 1 Then move the cursor to either Save or Restore and press the Enter key Configuration saved When a configuration has been saved the menu shown here willbe Press Home to exit displayed indicating that the current instrument setup has been written to the controller s FLASH memory and may be retrieved by using the Restore function If the user attempts to restore an invalid configuration an error display is shown This is usually caused by attempting to restore a configur
115. e 32 Autotune Menu nn rn nenannnnnnnn 91 Table 33 First CalGen Menu Diode Sensor i 107 Table 34 CalGen Menu 2 point Diode Sensor ccccccccccnccncncnononononononenenonenenenenos 108 Table 35 CalGen New Curve MENU nn eene 109 Table 36 Recommended GPIB Host Setup Parameters 145 Table 37 Remote Command SUMMAFYy i 229 Table 38 Factory Installed SENSors ii 234 Table 39 S700 Cable Color Codes 256 vii Cryo con Model 32 Index of Figures Figure 2 Model 32 Front Panel Layout nano ncnr rana nn 17 Figure 3 Model 32 Rear Panel Layout cnn r nano ncn rro nn 75 Figure 4 Proper Assembly of the Input Connector i TI Figure 5 Diode and Resistor Sensor Connections nana nannnnnn no 78 Figure 7 RS 232 Null Modem Cable ooooooiococcoonococcnononaccnononan cnn nonn cnn r nano ncnr nano nn 81 Figure 8 Instrument Calibration Screen 137 viii Cryo con Model 32 Cryo con Model 32 Preparing the controller for use The following steps help you verify that the controller is ready for use Supplied Items Verify that you have received the following items with your controller If anything is missing contact Cryogenic Control Systems Inc directly Model 32 32B Cryogenic Temperature Controller a User s M
116. e Bias Selections Excitation current sources used with constant voltage bias are calibrated from 1 0mA to 0 1uA so that the accuracy of resistance measurement will be 0 1 Accuracy will steadily degrade at lower excitation currents down to the minimum available output current of 10nA where the accuracy of resistance measurement is about 0 7 The tradeoff in measurement accuracy vs minimum 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 In order to minimize large jumps in self heating the Model 32 uses current sources to cover the 1 0mA to 10nA in steps of 5 power Resistance Measurement Accuracy 3 30 43KQ 430KQ 10 10KQ Table 18 NTC Resistor Measurement Accuracy Cryo con Model 32 Supported Sensor Types A complete list of the sensor types supported by the Model 32 is shown below Max Bias ee Sensor Excitation Type Voltage Type Current Typical Use Resistance R625R1MA R312R1MA R125R1MA 0 Snone 0 Disable Input Channel Pt 100 gt 800K Pt 100 lt 800K Rhodium lron _ 0 80mV thermocouple O 0 40mV thermocouple Diode Silic
117. e a booster supply with the Loop 1 output setup the controller as follows 1 Setthe Loop 1 Load Resistance to 250 by using the Heater Configuration Menu 2 On the Heater Setup Menu set the Heater Range to Low This will cause the loop to output a full scale programming current of 0 1A 3 Ifthe booster supply requires a voltage input the loop output will need a programming resistor to set the full scale programming voltage This resistor can be installed across the input terminals of the power supply 4 Connect the Loop 1 output to the booster supply to the programming input of the booster supply and set up the supply according to the manufacturer s documentation Example Many programmable power supplies require a zero to 10 Volt programming voltage The value of the programming resistor is R 10 Volts 0 1mA 100 Ohms Also note that the resistor must be capable of dissipating power Watts 10 Volts 0 1mA 1 0 Watts 98 Cryo con Model 32 Using a booster supply with Loop 2 of a Model 32 is simple since the loop outputs 0 to 10 Volts and can be connected directly to most programmable power supplies However Loop 2 of a Model 32B is more difficult since it is designed to output 10 Watts To use a booster supply with the Loop 2 of the Model 32B setup as follows 1 Loop 2 of a Model 32B outputs 450mA at up to 25 Volts Therefore to generate a zero to 10 Volt output you must use a 25 Ohm prog
118. e a range select the desired range from the range type tabs and enter the desired Gain and Offset values in the boxes given and then click the APPLY button Gain is a unit less gain factor that is scaled to a nominal value of 1 0 It is usually computed by gain UT LT UM LM where UT is the upper target and LT is the lower target UM is the upper measurement and LM is the lower measurement Gain values greater than 1 2 or less than 0 8 are rejected as out of range Offset is in units of Volts or Ohms depending on the calibration type Nominal value is 0 0 Positive or negative numbers are accepted It is usually calculated by Offset UT gain UM 138 Cryo con Model 32 Automatic Calibration Automatic calibration uses the left hand side of the calibration screen and is a four step process 1 Line 1 requires setting a upper target value on the input channel Depending on the calibration range selected this will be in Volts or Ohms First establish a voltage or resistance on the selected input channel that is near the recommended value Then enter the actual value in the box provided Click the Capture button on Line 2 The software will wait for the reading to stabilize and then will capture the reading and display it in the edit box on Line 2 While waiting for a stable reading the following dialog box will be displayed Capturing Data in Progress Capturing input data from instrument W
119. e according to the above description Fields within an entry are separated by one or more white space characters The last entry in a calibration curve must be a single semicolon Query Syntax PIDTABLE lt index gt TABLE Query Response lt Table entries gt Where lt Table entries gt are the entries of the selected PID table 206 Cryo con Model 32 CALDATA and SENTYPE Commands The CALDATA commands are used to add delete or edit user installed sensors These commands are the remote equivalent of the front panel Sensor Setup menu SENTYPE commands are used to query the name of a factory installed sensor User installed sensors are indexed from zero to 3 Factory installed sensors are indexed from zero to 60 For additional information refer to Appendix A CALDATA NAME Name for a user installed sensor Sets or queries the name of a user installed sensor Command Syntax CALDATA lt index gt NAME lt val gt Where lt index gt is the index of the user installed sensor and lt val gt the sensor s name string The name string must be surrounded with double quotation marks Query Syntax CALDATA lt index gt NAME Query Response lt name gt Where lt index gt is the index of the user installed sensor and lt name gt is the name string for the indexed sensor Query Short Form CALD lt index gt Where lt index gt is the index of the user installed sensor and lt val gt the sensor s name string Query
120. e 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 setpoint is reached ramping mode will terminate and temperature regulation will begin at the new setpoint 94 Cryo con Model 32 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 will disrupt the loop and degrade the accuracy of control If a fast PID loop is used it will attempt to track the signature which usually results in placing a waveform on the loop output heater that causes control performan
121. e changed from the front panel Sensor Type is an enumeration of all of the basic sensor types supported by the Model 32 Choices are shown in the Supported Sensor Configurations table above 51 Cryo con Model 32 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 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 Selecting the EDIT CAL CURVE field will cause the screen to go to the Calibration Curve menu for the selected sensor Here the calibration curve may be viewed or edited The Calibration Curve menu The Calibration Curve menu is the first screen used in the process of building a sensor calibration curve Note that these curves can have up to 200 points requiring the e
122. e control loop by outputting available power levels in a controlled sequence so that the average power is somewhere between the levels available in the controller s hardware Here the averaging function is performed by the system dynamics Control Accuracy Major error sources in a digital control loop are the input quantizer ADC the Digital Signal Processing mathematical operations and the output quantizer DAC Cryo con controllers use a 24 bit Analog to Digital converter This is the best available with modern components and it establishes the measurement resolution of the controller If all other functions were perfect this ADC would also establish the accuracy of the control loop In order to preserve accuracy the mathematical operations in a digital control loop must be performed to a much higher resolution than the input ADC Therefore Cryo con controllers all use 32 bit floating point arithmetic Finally a high precision loop output value reaches the output quantizer which is usually a 16 or 18 bit Digital to Analog converter Since this DAC has much less resolution than the earlier stages it generally establishes the accuracy of the accuracy of the entire loop A loop output value has been generated to a very high precision but the DAC throws away most of this precision to fit its available output levels Like the color synthesis example above signal dithering can be applied to the digital control loop so that the averag
123. e maintained in FLASH type memory and may be upgraded via the remote interface ports Instrument firmware updates are available on the Internet 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 Extrusion Machined Aluminum front and rear panels Power Requirement 100 120 220 or 240VAC 5 10 50 or 60Hz 150VA max 59 Cryo con Model 32 Input Channels There are two independent multi purpose input channels each of which can separately be configured for use with any supported sensor The Sensor Type is selected by the user via the microprocessor Values of excitation current voltage gain etc will be determined by the microprocessor and used to automatically configure the channel There are no internal jumpers or switches Constant Current Sensor Excitation Cryogenic sensors including Diode and Platinum devices require a constant current excitation To support this the Model 32 has a constant current excitation mode with three selectable outputs of 10uA 100uA and 1 0mA DC The maximum compliance of the constant current source is 2 45V Temperature is measured with diode type sensors by providing a 10uA excitation current and reading the resulting voltage The Model 32 uses a Ratiometric bridge technique to measure resistor sensors Here the measureme
124. e 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 242 Cryo con Model 32 Symptom Condition DC offset in Possible causes temperature The wrong sensor type or sensor calibration curve measurements is being used Refer to the Input Channel Setup 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 the CalGen feature to generate a new sensor calibration curve that corrects for these errors No temperature reading Review the Error Displays section above 243 Cryo con Model 32 Rem
125. e output value converges to the high precision value computed before output quantization The result is much greater control accuracy 247 Cryo con Model 32 Conventional Control Loop Output The diagram to the right shows the conventional method of generating an analog output from a digital control loop Here a high precision loop output value is computed then the value is truncated or rounded to fit the precision of the output DAC Precision above the resolution of the DAC is lost four quantization levels labeled Q1 E Qs through Q4 Dashed lines show the mid points between adjacent levels E e ene n nen ene neeeee Here the desired high precision control i QI xxx x x x x x x x loop output 0 is between levels Q2 So die and Q3 For simplicity ten output AIA Teor intervals of a DC level are shown Q2 Using an arithmetic rounding scheme if the desired output is above the mid point between two quantization levels Q1 the DAC output will be at the higher n Ann level If the value is below the mid point the DAC will output the lower level Therefore the DAC output x for the input shown will simply be Q3 As can be seen the average value of the DAC output is equal to the nearest quantization level In this example the output Q3 is slightly higher than the value required to accurately control at the selected setpoint Therefore the control loop will integrate downwards until the DAC output jumps down to
126. e the amp and keys to move up and down the list 32 Cryo con Model 32 ChA ChB Setup Menu A 77 123 KN Input channel units Temperature is displayed on the left and is in the selected 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 ASen I20 Pt100 385 N Sensor type selection Allows selection of any user or factory installed sensor The 120 shown indicates that the current sensor is factory installed sensor 20 ACalGen n Selecting this field by pressing the Enter key will take the display to the CalGen screen AHigh Alarm 200 000 Setpoint for the High Temperature alarm Use the keypad for numeric entry and then press the Enter key AHigh Enable Noh High temperature alarm enable Selections are Yes or No HLow Alarm 200 000 Setpoint for the Low Temperature alarm FALow Enable Yesh Enables latching alarms on the selected input channel HAudible Ena Yesh Enables the internal audio alarm to sound on any enabled alarm condition HLatch Enable Yesh Enables or disables latching alarm conditions A latched alarm is cleared by pressing the Alarm key followed by Home key 10 AMax 77 5232K a Continuously displays the Maximum temperature on this input channel Pressing the Enter key resets
127. e thermocouple s calibration curve The back shell of the input connector should always be installed This will minimize errors caused by local air currents Offset Calibration Offset calibration is used to calibrate the Cold Junction Compensation circuit and is recommended when a thermocouple is first installed or any time a thermocouple is changed An appropriate curve must be selected and Cold Junction Compensation must be enabled before calibration can be started 1 Connect the thermocouple 2 Locate the controller away from drafts as these may affect compensation 3 Allow the instrument to warm up for at least hour without moving or handling the sensor 4 Insert the thermocouple into the ice bath liquid nitrogen liquid helium or other know fixed temperature The temperature should be close to the measurement temperature that requires best accuracy 5 Read the displayed temperature in units of K or C then subtract the known actual temperature from the reading to determine the CJ offset value 6 Enter the CJ offset value into the controller by going to the SYS menu and scrolling down to the CJ offset field This completes the procedure Check the calibration by verifying that the correct temperature is being read 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 us
128. e two temperature control loops A status of OFF indicates that both loops are disabled and the output power levels are zero A status of ON indicates that the loops are engaged and actively controlling temperature Command Syntax N A The CONTROL command is used to engage the control loops and the STOP command is used to disengage them Query Syntax SYSTEM LOOP Query Response lt status gt Query Example SYSTEM LOOP Example Response OFF Indicating that both control loops are disengaged Short Form SYST LOOP 157 Cryo con Model 32 SYSTEM BEEP Sound the audible alarm Asserts the audible alarm for a specified number of seconds Command Syntax SYSTEM BEEP lt Sec gt Where lt Sec gt is the number of seconds to beep the audible alarm Command Example SYSTEM BEEP 10 Sounds the audible alarm for 10 seconds Short Form SYST BEEP SYSTEM DISTC Display Filter Time Constant The SYSTEM DISTC command is used to set or query the display filter time constant The display filter is applied to all reported or displayed temperature data Available time constants are 0 5 1 2 4 8 16 32 or 64 Seconds Command Syntax SYSTEM DISTC lt tc gt Where lt tc gt is the display filter time constant in seconds selected from the following list 0 5 1 2 4 8 16 32 64 Query Syntax SYSTEM DISTC Query Response lt tc gt Command Example SYSTEM DISTC 8 This command will set the display time consta
129. eadback 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 monitor is jumping up and down by about 1 This is normal and does not indicate unstable heater power The output current monitor is coarsely quantized and is displayed only for an indication of proper function The controller should be applying power but the display is showing 0 output The output indicated on the display is the actual measured output power of the control loop A reading of 0 while the controller is attempting to output power usually indicates an open heater 239 Cryo con Model 32 Symptom Condition 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 sto
130. ected control loop This is a numeric field with units of inverse seconds Allowed values are 0 off through 1000 Seconds The D gain term is applied to the selected control loop when controlling in a PID mode Note Use of the D gain term can add significant noise In most cryogenic applications it is set to zero Command Syntax LOOP lt no gt DGAIN lt value gt Where lt no gt is the loop number 1 or 2 and lt value gt is the desired D term for the selected control loop in inverse Seconds Query Syntax LOOP lt no gt DGAIN Query Response lt value gt Command Example LOOP 1 DGAIN 4 3 Sets control loop 1 differentiator feedback term to 4 3 Seconds Query Example LOOP 1 DGAIN Example Response 8 23 Indicates that the D feedback term for loop 1 is 8 23 Seconds Short Form LOOP DGA LOOP OUTPWR Control loop Output Power Queries the output power of the selected control loop This is a numeric field that is a percent of full scale Query Syntax LOOP lt no gt OUTPWR Where lt no gt is the loop number 1 or 2 Query Response lt value gt Where lt value gt is the selected control loop output power setting in percent Query Example LOOP 2 0UTP Example Response 75 000 Indicates that the control loop 2 is attempting to output 75 of full scale power Short Form LOOP OUTP 193 Cryo con Model 32 LOOP HTRREAD Heater read back current Queries the actual output power of either contro
131. ections as described above Ensure that the proper sensor has been selected Refer to the Input Channel Setup Menus 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 Sensor Setup to display the calibration curve 237 Cryo con Model 32 Display Condition Reading Record 0000 o Errors The controller s firmware has been corrupted Invalid Checksum Re load the unit s firmware Refer to the section Downloading Instrument Firmware ADC Failure The input temperature measurement circuitry has failed Contact Cryo con technical support The self test procedure detected an error in the controller s RAM memory Contact Cryo con Support 238 Cryo con Model 32 Control Loop and Heater Problems Symptom Condition Overtemp displayed The control loops were disengaged by detection of an excessive internal temperature Possible causes Shorted heater Check heater resistance Selection 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 R
132. ed 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 26 AC Power Line Fuses 76 Cryo con Model 32 Sensor Connections All sensor connections are made at the rear panel of the Model 32 using the two DIN 5 receptacles provided Standard Four Wire Sensor Connections Silicon Diode and all resistor type sensors should be connected to the Model 32 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 backshell of the connector Excitation l Sense V Do not connect O O Sense V 5 Excitation I 1 2 3 4 Table 27 Input Connector Pin out Caution To ensure proper low noise operation cable shields should be connected to the metal backshell 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 4 Proper Assembly of the Input Connector 77 Cryo con Model 32
133. ed to confirm that you really want to update calibration memory 140 Cryo con Model 32 Summary of Calibration Types Calibration data must be generated for each input channel by sequencing through the various calibration types on each channel A summary of types is given here Calibration Voltage Output Description Type Range Current P SI DiodeV 0 25V N A Voltage measurement for use with Silicon Diode temperature sensors i 10uA constant current source used SI Diog Na 10A with Silicon Diode sensors 1mA AC 10mV Autoranged 1mA range used with constant 1 25Hz voltage mode sensors 10mV 100uA range used with constant US 1 25Hz Auoranged voltage mode sensors 10uA AC 10mV Autoranged 10uA range used with constant 1 25Hz voltage mode sensors 1mA DC 0 2 5VDC 1 0mA DC measurement of 100 Platinum RTD sensors DC measurement of 1K Ohm 100uA DC 0 2 5VDC 100uA Platinum RTDs DC measurement of 10K Ohm Platinum RTDs or other resistor 100A DE JUDO tone sensors that use DC current excitation Thermocouple measurements Valid VTC80 pera N A only when optional thermocouple input is installed 141 Cryo con Model 32 Calibration of Silicon Diodes Silicon Diode sensors require the application of a precision 10pA current followed by reading the voltage drop across the device Therefore calibration of a diode requires two steps 1 Calibration of the input voltage reading and 2 C
134. eeeeteeeeees 60 Constant Voltage Sensor Excitation reee 60 Supported Sensor Types 62 Sensor Performance Summary nono nnnn nn 66 Factory Installed Sensors e 69 CalGen Calibration Curve Generator ne 69 Input Channel Statistics ennenen nener ener rnnr reerernn rennene 69 Electrical Isolation and Input Protection 69 Thermal EMF and AC Bias Issues nono 69 Gontrol QUIputs nitore io ra ani aaa 71 Control Loop 1 Primary Heater Output 71 Control Loop 2 Secondary Heater Output 72 Control TYPOS cocacola e cases A lada Ri 73 Alarm QUIputs aii elias 74 Remote Interfaces no nnnnnnnnnn nan iaaii 74 Rear Panel Connections neet 75 AC Power Connection 75 Fuse Replacement and Voltage Selection i 76 Sensor Connections a O aR E ETELE Sa 77 Loop 1 Heater Connections 80 Loop 2 Output Connections 80 IEEE 488 2 Connections et 80 RS 232 Connections 0 ariani 80 ii Cryo con Model 32 Mechanical Form Factors and Environmental 81 DIS dde art S 81 A lei aaa rear ariani 82 AG POWER vai ia nari aaa 82 Environmental and Safety CONCErns
135. el sensor bias voltage 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 Command Syntax INPUT lt channel gt VBIAS lt volts gt Where lt channel gt is the input channel parameter and lt volts gt is the bias voltage Choices are 10mV 10milliVolt 3 3mV 3 33milliVolt mv 1 0milliVolt Query Syntax INPUT lt channel gt VBIAS Where lt channel gt is the input channel indicator Query Response lt volts gt Command Example INPUT B VBIAS 3 3mV Query Example INP A VBias Example Response 1 0mV Note if the sensor on channel A is not a type ACR the response will always be N A Short Form INP VBIAS 172 Cryo con Model 32 INPUT ISENIX Installed Sensor index Sets or queries the sensor index number assigned to an input channel for factory installed sensors Sensor index zero indicates that there is no sensor connected to the selected input channel This will disable all readings on the channel Refer to Appendix A for a description of sensors indices etc Note The use of the ISENIX command to assign a factory installed sensor and the USENIX command to assign a user sensor are preferred to the use of the obsolete SENIX command
136. ement to stabilize When the measurement is stable select the Capture field next to the temperature field This will cause the Model 32 to capture the sensor reading and associate it with the specified temperature When a sensor reading has been 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 is stable at the required temperature Next the second temperature must be entered in the same way as before 108 Cryo con Model 32 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 1 15 User Sensor 1 H generated curve Numeric entry Note only the user curves can be written Pressing the Enter key will cause the E E generation of a new curve The curve 2 Save e 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 sele
137. emperature ramp control Uses PID control to perform a temperature ramp Table 5 Control Type Summary Caution The Model 32 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 SYS Auto Ctl function in the System Functions menu section 14 Cryo con Model 32 Configuring the Loop 2 Output The second control loop of a Model 32B controller is a fixed 10 Watt output that is matched to a 500 resistive load Therefore there are no load resistance or range settings to configure On the standard Model 32 the second control loop is a zero to 10 Volt output that is intended to drive a booster supply or other voltage controlled device It is not a heater output All other configuration settings are identical for both Loop 1 and Loop 2 Caution The Model 32 has an automatic control on power up feature lf enabled the controller will automatically begin controlling temperature whenever AC power is applied For a complete description of this function please see the SYS 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 2 Press and hold the Enter key while turning AC power back ON Keep the key pressed until you see
138. en With Diode Sensors i 107 Using CalGen With Platinum and Thermocouple Sensors 109 iii Cryo con Model 32 System Shielding and Grounding ISSUES i 111 Grounding SCHEME cach nali aeneon 111 The Single Point Ground i 111 AG PoWer ENYA 111 Sensor Connection ae aaa REE E ae A O 111 Control LOOPS siii sd 112 Digital GirGUits eoe r AREE iaia ani 112 Cryo con Utility Software oo aarin i 115 Installing the Utility Software i 115 Connecting to an Instrument 116 Using the Interactive Terminal 117 Downloading or Uploading a Sensor Calibration Curve 118 Using the Real Time Strip Charts 122 Bata togging ea es e Raa A pean 123 Remote I O command HELP 125 CalGen Calibration Curve Generator i 126 CalGen Initial Setup no nccnnn 126 Using CalGen With Diode SEensors i 126 Using CalGen With Resistor SEnsors i 127 Example CalGen Procedure rn 127 The Vapor Pressure Calculator 129 Downloading Instrument Firmware 131 Instrument Calibration nn nnnnnnnnnns 135 Cryo con Calibration Services cana nn 135 Galibration Intervali uscsl na aiar 135 Minimum Required Equipment 136 The Basic Calibration Sequence
139. ensor input channels Controller with one standard input and one Modeka Model S2B5t universal thermocouple input Technical Assistance Trouble shooting 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 Telephone 858 756 3900x100 FAX 858 759 3515 e mail techsupport cryocon com Cryo con Model 32 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 December 2006 the current firmware revision level for the Model 32 series is 6 10 Current Hardware Revision Level As of December 2006 the current hardware revision level for the Model 32 series is H Hardware cannot be upgraded in the field Cryo con Model 32 Options and Accessories Instrument Accessories Cryo con Part Description 4034 031 Two instrument shelf rack mount kit 4034 032 One instrument shelf rack mount kit RS 232 Null Modem Cable 6 Required for 04 0420 downloading firmware to the instrument products 4034 035 Shielded IEEE 488 2 Interface Bus Cable 6 6 4039 010 Cable Assembly 10 Pin to Modular Test Dewar 4039 009 Cable Assembly 19 Pin to Modular Test Dewar 04 0310 A
140. ensor s calibration curve It is important that Thermocouple sensors be connected directly to the input connector as described in the section below For example if the thermocouple wires were first connected to Copper wires then to the Model 32 input the Cold Junction Compensation cannot function properly and measurement errors will result The Cold Junction Compensation function may be turned On or Off for each input channel This is done by using the CJcomp field of the Input Channel Setup Menu Adding New Thermocouple Types New thermocouple types may be added to the Model 32 by adding a new user sensor type and corresponding calibration curve This procedure is described in the section below titled Adding a New Sensor Since the software Cold Junction Compensation technique used by the Model 32 depends on the thermocouple s calibration curve it is important to note that the temperature range of the curve must include room temperature Cold Junction Compensation Errors Cold Junction Compensation is required for any instrument to measure thermocouple sensors accurately The most accurate method for performing this is by using an external Ice Bath setup However this is often impractical 100 Cryo con Model 32 Cold Junction Compensation in the Model 32 controller is performed by a circuit that measures the temperature of the input connector pins This reading is then used to look up a compensating voltage from th
141. ent Status Enable Register ISE A The Standard Event Register ESA A The Standard Event Enable Register ESE 2 The Status Byte STB A The Status Enable Register SRE A Name Strings A Curve Multiplier A Curve Units A Sensor Types A Input Channel Designators o Remote Command Reference 125 Cryo con Model 32 CalGen Calibration Curve Generator The CalGen feature is used to generate new calibration curves for Silicon Diode or resistor 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 New Curves can be generated from any user selected sensor calibration curve and are written to a specified file For Diode sensors the user may specify one two or three data points CalGen will generate the new curve based on fitting the input curve to the user specified points Platinum or other resistor calibration curves require one or two data points The generated curve will be 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 instrument s measurement electronics are also effectively cancelled CalGen Initial Set
142. ents will require a password before calibration data can be saved The utility software will allow you to enter and change the password The default password is cryocon On the far right of the screen a drop down box selects the channel to be calibrated Be sure you have selected the correct channel In order to perform a complete calibration you will need to calibrate each channel individually Along the top of the screen there are tabs that show the types of calibration that are supported by the instrument To perform a complete calibration of a single input channel all calibration types must be calibrated Note the Calibration Results box on the screen The Status field will initially be set to Current and the Gain and Offset values shown will be those read from the instrument c Note If your calibration procedure requires saving historical values you will want to record the Gain and Offset values shown on the initial screen before proceeding with actual calibration 137 Cryo con Model 32 There are two methods available for calibration 1 Automatic The software will recommend voltages and resistances You can set these values on the input channel and capture the instrument s actual readings Then the software will automatically generate offset and gain values for you 2 Manual You can manually enter Offset and Gain values and send them to the instrument Manual Calibration To manually calibrat
143. erature for thermocouple sensors SYSTEM PUCONTROL SYSTEM PUCONTROL Sets or queries the power up in control mode setting SYSTEM LINEFREQ SYSTEM LINEFREQ Sets or queries the AC Power Line frequency setting SYSTEM SETUP RESTORE Saves the current instrument setup to a user setup SYSTEM NVSAVE Save the instrument configuration to flash memory so that it will be restored on the next power up SYSTEM CONTRAST SYSTEM CONTRAST Set or query the contrast of the front panel VFD display Model 34 62 Only 222 Cryo con Model 32 CONFIG commands CONFIG NAME Sets or queries the name of a user setup CONFIG SAVE Saves the current instrument setup to a user setup CONFIG RESTORE Restores a previously saved instrument configuration 223 Cryo con Model 32 Command Function Input Channel Commands INPUT Query the current temperature reading on any of the INPUT TEMPER input channels INPUT UNITS Sets or reports the display units of temperature used INPUT UNITS by the specified input channel INPUT ISENIX Sets or queries the sensor index number assigned to INPUT ISENIX an input channel Applies to factory installed sensors Refer to Appendix A INPUT USENIX Sets or queries the sensor index number assigned to INPUT USENIX an input channel Applies to user installed sensors Refer to Appendix A INPUT SENIX Obsolete Use USENI
144. erm 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 1 5 0 and D 0 0 251 Cryo con Model 32 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 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 system into temperature oscillation Care should be taken so
145. esistor sensors such as Thermistors Platinum RTDs 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 Pl 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 PI 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
146. esponse 250 000 Identifies the autotune timeout period as 250 seconds Short Form AUT TIM AUTOTUNE START Initiate Autotune Initiates the autotune sequence Command Syntax lt oc gt AUTOTUNE START Where lt oc gt is the output channel to tune and may be either LOOP 10r LOOP 2 Command Example LOOP 1 AUTOTUNE START Initiates autotuning the heater Short Form AUT STAR 212 Cryo con Model 32 AUTOTUNE EXIT Abort Autotune Aborts and exits the autotune process Command Syntax lt oc gt AUTOTUNE EXIT Where lt oc gt is the output channel to tune and may be either LOOP 10r LOOP 2 Command Example LOOP 2 AUTOTUNE EXIT Aborts autotuning Short Form AUT EXIT AUTOTUNE SAVE Save PID Coefficients When an autotune sequence has successfully completed this command will save the generated PID values to the control loop PID values and change the autotune state from complete to idle Command Syntax lt oc gt AUTOTUNE SAVE Where lt oc gt is the output channel to tune and may be either LOOP 10r LOOP 2 Command Example LOOP 2 AUTO SAVE Short Form AUT SAVE AUTOTUNE PGAIN Proportional Gain When an autotune sequence has successfully completed the AUTOTUNE PGAIN command can be used to query the generated P or P gain term Query Syntax lt oc gt AUTOTUNE PGAIN Query Response lt value gt Where lt oc gt is the output channel to tune and may be either LOOP 1 or LOOP 2 lt
147. f any current can flow back through the system grounds 112 Cryo con Model 32 The GPIB Connection The GPIB is a 24 wire communications protocol that has six control signal grounds one data signal ground and one shield ground In the Cryo con controller the control and signal grounds are connected together and used to establish the ground reference potential for the digital area The Shield ground connection is connected to the instrument s Single Point Ground through a jumper The jumper is available since some manufacturers connect the GPIB shield ground to their circuit board ground and therefore ground loops are established through the shields Removing the jumper will break this ground 113 Cryo con Model 32 114 Cryo con Model 32 Cryo con Utility Software Cryo con provides a PC compatible utility software package with all instruments This is available on CD or on the Internet Utility software can be used to control and configure any Cryo con instrument via the RS 232 LAN USB or IEEE 488 interface It runs under all versions of the Windows operating system This software provides several useful functions including 1 Real time strip charts of temperature 2 Data Logging This function allows the user to record data from the instrument at a specified sample rate The resulting file is compatible with most spreadsheet and data analysis software 3 Download or upload sensor calibration cur
148. for NTC sensors Cryo con Model 32 Sensor Type Type K Type E Type T C AuFe 07 Input Range 80mV 80mV 40mV 40mV Sensor 300K 41uV K 300K 61uV K 300K 41uV K 300K 22 4uV K Sensitivity 1500K 36uV K 1200K 76uV K 600K 60uV K 600K 23 4uV K Measurement 300K 0 6uV 300K 0 6uV 300K 0 5uV 300K 0 5uV Accuracy 1500K 6 7uV 1200K 9 0uV 600K 4 0uV 600K 2 0pV Temperature 300K 15mK 300K 11mK 300K 12mK 300K 17mK Measurement 1500K 190mK 1200K 122mK 600K 75mK 600K 90mK Accuracy Measurement 300K 0 5uV 300K 0 5uV 300K 0 4uV 300K 0 4uV Resolution 1500K 0 5uV 1200K 0 5uV 600K 0 4uV 600K 0 4uV Temperature 300K 11mK 300K 11mK 300K 12mK sone IK Resolution 1500K 13mK 1200K 13mK 600K 73mK pc xa 300K 110mK 300K 56mK 300K 60mK 300K 66mK Control Stability 1500K 100mk 1200K 55mK 600K 56mK 600K 65mK Magneto resistance Very Large Very Large Very Large Very Large Includes error from internal cold junction compensation Table 24 Sensor Performance for Thermocouple Sensors 68 Cryo con Model 32 Factory Installed Sensors For a listing of factory installed sensors refer to Appendix A CalGen Calibration Curve Generator 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 me
149. he base ten logarithm of ohms and is useful with sensors whose fundamental resistance vs temperature curve is logarithmic The LogOhm selection is only used with Negative Temperature Coefficient resistor sensors where it acts to improve the accuracy of interpolation The N field is the number of valid points in the calibration curve and is generated from the entries made during the editing process Selecting the EDIT CAL CURVE field will cause the screen to go to the Calibration Curve menu for the selected sensor Here the calibration curve may be entered or edited Calibration Curve Entry Once a sensor type is defined the calibration curve for that sensor may be entered This may be done by using the Calibration Curves Menu described above or using any of the remote I O ports or using the Model 32 Utility Software package One very efficient way to enter a new calibration curve is to use the instrument s CalGen feature to generate a new curve from an existing one Operation of this feature is described below 87 Cryo con Model 32 Autotuning The Autotune Process The Model 32 performs autotuning by applying a generated waveform to the heater output and analyzing the resulting changes in process temperature This is used to develop a process model then a PID solution It is important to note that there is a range of PID combinations that will provide accurate control for a given process Further process mode
150. heater Loop 2 is a secondary output In the Model 32 this is a 0 5V voltage output that can drive a strip chart recorder or a booster power supply Loop 2 of the Model 32B is a 10 Watt single range linear heater LOOP SOURCE Control loop Source Input Channel Sets and queries the selected control loop s controlling input channel Command Syntax LOOP lt no gt SOURCE lt chan gt Where lt no gt is the loop number 1 or 2 and lt chan gt is the designator of the controlling input channel Query Syntax LOOP lt no gt SOURCE Query Response lt chan gt Where lt chan gt is the designator of the controlling input channel Command Example LOOP 1 SOUR CHA Sets the control loop feedback loop to be controlled by input channel A Command Example LOOP 1 SOUR CHB SETPT 123 4 PGAIN 120 This command will set control loop 1 s setpoint to 123 4 the proportional gain term to 120 and the control input channel to B Query Example LOOP 2 SOURCE Example Response CHB Which indicates that the control loop 2 is being controlled by input channel B Short Form LOOP SOUR 186 Cryo con Model 32 LOOP SETPT Control loop Setpoint 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 Allowed values are OK to 1000K Command Syntax LOOP lt no gt SETPT lt temp gt Where lt no gt is the loop number 1 or 2 a
151. hite space gt lt data gt lt function gt lt white space gt lt data gt lt terminator gt Command headers immediately followed by a question mark are queries After receiving a query the instrument interrogates the requested function and places the response in it s output queue The output message remains in the queue until it is read or another command is issued Query commands are used to find out how the instrument is currently configured They are also used to get results of measurements c Note The output queue must be read before the next command is sent For example when you send the query you must follow it with an input statement Truncation of Keywords If a keyword contains more than four characters it may be truncated to four or less characters to simplify programming 148 Cryo con Model 32 The truncated 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 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 Bit7 Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0 Alarm Htr SFB SFA
152. ication 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 you select Cryo con recommends that complete re adjustment should always be performed at the calibration interval This will increase your 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 extend future calibration intervals 135 Cryo con Model 32 Minimum Required Equipment All calibrations require a computer with an RS 232 or IEEE 488 connection to the instrument Additionally reference standards are required for each input range as follows e The Silicon Diode input range Calibration Type I10UA and V10UA requires voltage references of 0 5 and 1 5 Volts DC and a resistance standard of 100KQ e The Constant Voltage AC resistance ranges Type AC10UA AC100UA and AC10UA require the use of 100KQ 10KQ 1KQ 1000 and 100 resistances e The 1000 Platinum range Type R1MA requires a 1000 and a 100 resistor e The 10000 range Type R100UA requires 1K Q and 100 Q resistors e The 10 0000 range Type R10UA requires 10KQ and 1KO resistors e The 80mV the
153. icator is OFF Command Syntax SYSTEM LOCKOUT lt status gt Where lt status gt is either ON or OFF A lt status gt of ON will lock out the front panel keypad Query Syntax SYSTEM LOCKOUT Query Response lt status gt Query Example SYSTEM LOCKOUT Example Response OFF Indicating that the front panel keypad is enabled Short Form SYST LOCK SYSTEM NVSAVE Save NVRAM to flash 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 Command Syntax SYSTEM NVSAVE Short Form SYST NVS 156 Cryo con Model 32 SYSTEM REMLED Front Panel Remote LED Sets or queries the remote LED status indicator on the Model 32 front panel The default condition for this indicator is OFF Note that the Remote LED is automatically handled by the GPIB interface but must be turned on and off when using the RS 232 interface Command Syntax SYSTEM REMLED lt status gt Where lt status gt is either ON or OFF A lt status gt of ON will illuminate the front panel Remote LED Query Syntax SYSTEM REMLED Query Response lt status gt Query Example SYSTEM REMLED Example Response OFF Indicating that the Remote LED is OFF Short Form SYST REML SYSTEM LOOP Control Loop On Off Reports the status of th
154. ield 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 Default is 1 0 for sensors with a positive temperature coefficient and 1 0 for a negative coefficient Command Syntax CALDATA lt index gt MULTIPLY lt val gt Where lt index gt is the index to user installed sensor 0 through 3 and lt val gt the multiplier lt index gt is an integer and lt val gt is floating point with a range of 100 0 Command Example CALD 1 MULT 10 1 This command sets the calibration table multiplier for user installed sensor 1 to 10 1 and identifies it as having a negative temperature coefficient Query Syntax CALDATA lt index gt MULTIPLY Query Response lt val gt Where lt index gt is the index and lt val gt is the sensor type multiplier Query Example CALD 2 MULT Example Response 1 000000 This response indicates that the sensor at index 2 has a positive temperature coefficient and a calibration curve multiplier of 1 0 Short Form CALD MULT 209 Cryo con Model 32 AUTOTUNE commands Autotuning via the remote interface requires the following sequence
155. ield with values between 0 off and 1000 The P gain term is applied to the control loop when controlling in a PID mode Command Syntax LOOP lt no gt PGAIN lt value gt Where lt no gt is the loop number 1 or 2 and lt value gt is the desired P term for the control loop Query Syntax LOOP lt no gt PGAIN Query Response lt value gt Command Example LOOP 1 PGAIN 123 Sets the heater P term to 123 Query Example LOOP 1 PGAIN Example Response 0 49723 Short Form LOOP PGA LOOP IGAIN Control Loop Integral Gain term 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 The integrator gain term is applied to the selected control loop when controlling in a PID mode Command Syntax LOOP lt no gt IGAIN lt value gt Where lt no gt is the loop number 1 or 2 and lt value gt is the desired Integral Gain term for the control loop in seconds Query Syntax LOOP lt no gt IGAIN Query Response lt value gt Command Example LOOP 1 IGAIN 12 422 Sets the Loop 1 integrator feedback term to 12 422 Seconds Query Example LOOP 2 IGAIN Example Response 18 23 Indicates that the Loop 2 channel feedback term is 18 23 Seconds Short Form LOOP IGA 192 Cryo con Model 32 LOOP DGAIN Control Loop Derivative Gain term Sets and queries the differentiator gain term used by the sel
156. ing a good quality ground point that the controller and sensor grounds are both connected to 2 Running a ground strap The preferred connection of the ground strap would be from a ground point near the sensor to the Third Wire ground connection of the controller s AC power cord If this is not available the strap can be connected to the controller s chassis 104 Cryo con Model 32 CalGen Calibration Curve Generator 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 will generate 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 will be 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 Model 3
157. ing download When the download is complete the controller will freeze and the PC will display a Download Complete dialog box Caution When a firmware download is complete the controller should automatically reset within 10 seconds Do not unplug it When the reset process is complete hold down the Enter key and power cycle the instrument from the front panel The new firmware should boot up If a non recoverable communications error occurs during firmware download the controller will power up in an error mode where it is looking for a new firmware transfer on the serial port The VFD screen will display the transfer display shown above In this case repeat the above procedure until the entire firmware transfer sequence works correctly c NOTE Factory defaults may be restored at any time by use of the following sequence 1 Turn power to the Model 32 OFF 2 Press and hold the Enter key while turning power back ON c NOTE The firmware download mode of the Model 32 may be forced by the following sequence 1 Turn power to the Model 32 OFF 2 Press and hold the Stop key while turning power back ON This sequence is intended for use when the controller is not operational and will not accept remote commands to place it in the download mode 133 Cryo con Model 32 134 Cryo con Model 32 Instrument Calibration Calibration of the Model 32 controller requires the u
158. ing of PID controllers Instrument Society of America 67 Alexander Dr PO Box 12277 Research Triangle Park NC 27709 253 Cryo con Model 32 254 Cryo con Model 32 Appendix E Sensor Calibration Curve Tables Cryocon S700 Silicon Diode The Cryocon S700 Silicon Diode sensor with a 101A excitation current 00 3004 NA 04 DSWN PO Sok kB kB SD O 00000000000 000000 00000000000 OOO OOD oOo ao q0 Volts 1633 1733 1834 1935 2038 2141 2246 2351 2458 2565 2613 2781 2891 3001 III 3222 3334 3446 3558 3671 3784 3897 125 239 353 467 581 695 808 4922 5035 5261 5373 5485 5596 5707 5900 Temp K 19 4 470 465 460 455 450 445 440 435 430 425 420 415 410 405 400 395 390 385 380 375 370 365 360 355 350 345 340 335 330 325 320 315 310 305 300 295 290 280 270 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 Os BP PB PB DB PB BB o 00 at O UTE w daa a UN n 0 daa an a a COWMWON DU RA Ov Ov OV UN E a Ov OV OV OV OD OV 0 0 JD UA Y N FE O JJ VAYA o 00 J004suN RR RR OO BO BO BO BA Ota ae Volts 6393 6586 6807 7040 123 746 768 791 813
159. iode sensors 70 Cryo con Model 32 Control 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 SOA then the output will be returned to normal operation Load resistance values of either 250 or 500 may be selected Using a 250 load the heater will be automatically configured to have a compliance voltage of 25V With a 500 load the compliance voltage is 50V In either case the maximum output current is 1 0A There are three output ranges which are manually selected in PID mode and automatically selected in the PID Table control mode The ranges are High Medium and Low Compliance Voltage Full Scale Max Output Power Range 250 500 Current 250 500 High 25 50 1 04 25 Watts 50 Watts Medium 25 50 0 333A 2 5 Watts 5 0 Watts Low 25 50 0 100A 0 25 Watts 0 50 Watts Table 25 Loop 1 Heater output ranges Care must be taken 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 connecti
160. ion may be selected by clicking Comm gt Port Select from the main menu Sensor Lurye Download FID Table Download Port Select Dialog 3 nteract Upload Data Log Select the desired communications port and then click OK 116 Cryo con Model 32 Click on the Connect button of the shortcut menu bar or on Comm gt Connect from the main menu to connect to the instrument After a short delay the connect LED should light and the instrument type will be displayed Also most of the grayed out fields on the menu bars should activate Using the Interactive Terminal The Utility Software s Interactive Terminal mode allows the user to send commands to the instrument and view the response Terminal mode is selected by selecting Comm gt Interact from the main menu or Interact from the shortcut bar This will result in the display shown below To interact with the instrument type a remote command into the dialog box and click Send The command will be transmitted to the instrument and a response if any will be displayed on the background window To exit terminal mode click the Quit button on the dialog box s Cryo con Utility Software dloader lol x Fie Comm Firmware Calibration Table PID Table View Data Logging Help Serial Terminal x Enter Command Send DN 117 Cryo con Model 32 Downloading or Uploading a Sensor Calibration Curve Sensor calibration curves may be t
161. is defined by the mask register for the STB lt 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 151 Cryo con Model 32 Remote Commands IEEE488 SCPI Common commands The Common Commands are defined by the IEEE 488 2 standard and are supported by the Model 32 on the GPIB port as well as all of the remote interface ports The common commands control some of the basic instrument functions such as instrument identification and reset They also provide an instrument status reporting mechanism CLS Clear Status Clear Status The CLS common command clears the status data structures including the device error queue and the MAV Message Available bit Command Syntax CLS Command Example CLS 152 Cryo con Model 32 ESE Event Status Enable Event Status Enable 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 ESE register will enable the corresponding bit in the SEV register A zero will disable the bit The ESE Query returns the current contents of the ESE register Command Syntax ESE lt mask gt Query Syntax ESE Command Example ESE 32 Query Response lt mask gt This will set the CME or Command Error bit enable Therefore
162. it off and refer to Appendix B Troubleshooting Guide Cryo con Model 32 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 five seconds the self test will complete and the controller will begin normal operation Cryo con Model 32 Installation General The Model 32 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 4034 032 Single instrument shelf rack mount kit 4034 031 Dual instrument shelf rack mount kit Since the controller is an industry standard size you can mount any similar size instrument next to it in the rack Note that the rack mount extends the height of the control
163. l 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 Command Syntax SYSTEM DRES lt res gt Where lt res gt is the display resolution as follows FULL 1 2 3 Command Example SYSTEM DRES 2 Causes the VFD display to show temperature with two digits to the right of the decimal point Query Syntax SYSTEM DRES Query Response lt res gt Where lt res gt is the display resolution Query Example SYSTEM DRES Example Response FULL Short Form SYST DRES 165 Cryo con Model 32 SYSTEM PUCONTROL Power up in control mode Sets or queries the controller s power up in control mode setting Reference the section on power up in control mode Default is OFF Command Syntax SYSTEM PUCONTROL lt mode gt Where lt mode gt is ON or OFF Command Example SYSTEM PUCONTROL OFF Causes the power up in control mode setting to select OFF Query Syntax SYSTEM PUCONTROL Query Response lt mode gt Where lt mode gt is ON or OFF Query Example SYSTEM PUC Example Response OFF Short Form SYST PUC 166 Cryo con Model 32 CONFIG commands The CONFIG commands are used to save and restore any of the six available user instrument setups Each setup contains the complete state of the controller CONFIG NAME User Setup Name Instrument
164. l loop The output current of the heaters in the Model 32 is continuously monitored by an independent read back circuit Read back power will be reported as a percent of full scale The absolute value of full scale is determined by the selected heater range as shown in this table Note that the read back value is a percent of full scale power To compute the output current you must first compute the square root of the read Current When using the second control loop of the Model 5 2 5 Watt 0 333A 32B the read back value is always a percentage 0 5 0 25 Watt 0 14 of 10 Watts 0 5 0 25 Watt 0 1A Query Syntax LOOP lt no gt HTRREAD Where lt no gt is the loop number 1 or 2 Query Response lt current gt Where lt current gt is the heater output current as a percent of full scale Query Example LOOP 1 HTRR Example Response 33 Indicates that the heater output current has been measured at 33 of full scale by the heater read back circuit If the heater s maximum output power is 50 Watts the output power is 50 0 33 16 5 Watts This corresponds to an output current of 1 0A sqrt 0 33 0 57A Short Form LOOP HTRR 194 Cryo con Model 32 LOOP 1 LOAD Heater Load Resistance Select 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 of the Model
165. ler from 2U 3 to 3U 5 To mount the controller first remove the plastic feet and instrument bail on the bottom of the unit Next lay the controller on the shelf and slide forward to line up with the front cutout Use four 6 1 4 screws to secure the controller using the same threaded holes as the plastic feet used Warning When rack mounting do not use screws that protrude into the bottom of instrument more than Y Otherwise they can touch internal circuitry and damage it Cryo con Model 32 Initial Setup and Configuration Before attempting to control temperature the following instrument parameters should be checked 1 The Loop 1Heater 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 250 should use the 250 setting Using the 500 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 Control Loop Setup menu section The Loop 1 heater range should be set to a range where the maximum output power will not damage your equipment To set this parameter press the Loop 1 key and refer to the Control Loop Setup menu section The controller has an over temperature disconnect feature that monitors a selected input and will disconnect both control
166. ling is a statistical method that is affected by noise and system non linearity As a result 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 will vary only in the resultant closed loop bandwidth Low bandwidth solutions will be slower to respond to changes in setpoint or load disturbances High bandwidth solutions will result be responsive but can exhibit overshoot and damped oscillation The Model 32 attempts to generate minimum overshoot solutions since many cryogenic temperature control applications require this If the process is noisy bandwidth will be minimized as much as possible If the process is very quiet a more aggressive solution will be generated subject to the minimum overshoot requirement The autotune algorithm will produce 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 that the user constrains the amplitude and duration of the heater output waveform by using the DeltaP and Timeout parameters Small values for DeltaP will force the use of small changes in heater power This will make the process mo
167. low AC line voltage Check the AC resets or resets when voltage and ensure that it matches the instrument s Control key is pressed voltage selection AC line voltage selection is described in the Fuse Replacement and Voltage Selection section Complete failure Possible cause 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 246 Cryo con Model 32 Appendix C Application Note on Signal Dither Using Dither in Digital Control Loops Dither as a signal or image processing technique is a method of extending dynamic range by first perturbing dithering then averaging The technique was first developed to enhance the performance of RADAR target algorithms and is now applied to a wide range of applications including navigation systems and consumer audio CD recordings Perhaps the most common example of a dithering technique is the synthesis of an artificial color on a computer screen by grouping available colors at adjacent pixels When viewed by the user the spatial averaging effect of the eye generates a color that is not available on the computer s color palette In Cryo con s temperature controllers dither is used to extend the dynamic range of a temperatur
168. mperature 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 45 Cryo con Model 32 Remote I O Port Configuration The RIO lines are used to configure the Remote I O interfaces including the GPIB and RS 232 Note that GPIB is used to indicate the controllers IEEE 488 2 interface Port Select RIO Port is an enumeration field that sets the active remote port The controller can only have one active port at a given time Inactive ports are disabled Choices are RS 232 and GPIB The factory default is RS 232 The address line RIO Address is a numeric field that may have a value between 1 and 31 The factory default is address 12 This field is used by the GPIB interface to select individual instruments It is the user s responsibility to configure the bus structure with unique addresses for each connected instrument RS232 Rate is an enumeration of the RS 232 baud rate Choices are 300 1200 2400 4800 9600 19k for 19 200 and 38K for 38 400 Synchronous Filter Configuration Numeric Entry Default 7 The Synchronous Filter 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 fr
169. n 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 The autotune sequence is initiated by selecting the Go field If the initialization of process modeling is successful the status display line will change from idle to Running If initialization is not successful one of the above listed conditions has not been met 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 will be 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 intervention such as pressing the Stop key 92 Cryo con Model 32 Temperature Ramping Operation The Model 32 will perform 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 will then progress to the new setpoint at the selected ramp rate Up
170. n Model 32 STATS commands Input channel statistics Temperature statistics on every enabled input channel are continuously accumulated Accumulation is initialized whenever a channel is first enabled or when a reset command is received The STATS commands include the RESET command and a TIME command that queries the duration of the accumulation Queries of statistical data are made using the INPUT commands STATS TIME Accumulation time Queries the time duration over which input channel statistics have been accumulated TIME is reset by issuing the STAT RESET command Query Syntax STATS TIME Query Response lt time gt Where lt time gt is the time in Seconds that has elapsed since the channel statistics were reset Query Example STATS TIME Example Response 232 Indicating 232 seconds have elapsed Short Form STAT TIM STATS RESET Reset Statistics Resets the accumulation of input channel statistical data Command Syntax STATS RESET Resets the accumulation of input channel statistics Command Example STATS RESET Short Form STAT RES 169 Cryo con Model 32 INPUT commands The INPUT group of commands are associated with the configuration and status of the four input channels INPUT may also be a stand alone query 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 INPU
171. n result in unacceptable measurement errors These cases will require the use of an AC bias or chopped sensor excitation in order to remove DC offsets 69 Cryo con Model 32 Sensor Wiring Diode and Platinum RTD type sensors use a DC measurement scheme Therefore the only effective method of minimizing Thermocouple DC offsets is to wire temperature sensors so that connections between dissimilar metals are grouped together For example the connection between sensor leads and cryostat wiring should be kept close together This way the Thermocouple junctions formed by the connection will have equal but opposite voltages and will cancel each other Frequently sensor leads are made from the same material as the cryostat wires Therefore there is no significant Thermocouple formed by this connection In a four wire measurement scheme only connections in the voltage sense lines can cause measurement errors So the sense wires should have adjacent contacts in a multi pin connector in order to minimize any temperature difference between them Usually the connection to copper in a cryostat is made at the top of the cryostat After this point Thermal EMFs cannot be generated AC Excitation When a sensor type of ACR or AC Resistance is selected the Model 32 uses a 1 25Hz square wave sensor excitation This eliminates DC offsets by computing the sensor resistance at two different excitation points This method will not work d
172. nd lt temp gt is the desired setpoint Query Syntax LOOP 1 SETPT Query Response lt temp gt Where lt temp gt is the setpoint temperature in units of the controlling input channel Command Example LOOP 1 SETPT 100 4 Sets loop 1 s setpoint to 100 4 If the controlling input channel units are Kelvin this command will result in a setpoint of 100 4K Multiple Command Example LOOP 2 SETPT 123 4 PGAIN 120 This command will set the loop 2 setpoint to 123 4 and the proportional gain term to 120 Query Example LOOP 1 SETPT Example Response 143 1293 Short Form LOOP SETP 187 Cryo con Model 32 LOOP TYPE Control loop Control Type 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 Command Syntax LOOP lt no gt TYPE lt type gt Where lt no gt is the loop number 1 or 2 and lt type gt is the loop s control type from the above list Query Syntax LOOP lt no gt TYPE Query Response lt type gt Where lt type gt is the loop type from the above list Command Example LOOP 1 TYPE PID Sets the loop 1 control mode to PID Query Example LOOP 1 TYPE Example Response TABLE Which indicates that the Loop 1 is controlling based on PID Table lookup Short Form LOOP TYPE 188 Cryo
173. ng download 16 revision level 1 7 154 164 222 update 115 131 fuse replacement 76 fuses 76 82 GPIB 46 74 149 151 152 159 160 Hardware Revision Level 7 163 Heater control modes 39 Dgain 37 38 fault 71 74 162 Igain 37 38 load 41 load resistance 37 71 maximum output 4 40 190 194 195 196 maximum setpoint 38 40 196 output 71 72 Pgain 37 38 Pman 37 38 range 39 48 50 71 73 190 read back 71 194 resistance selection 41 Cryo con Model 32 Safe Operating Area 71 setpoint 11 22 37 50 186 187 226 252 setpoint 38 setpoint entry 29 shut down 71 source selection 38 status 25 27 HOME key 24 IEEE 488 5 74 115 145 152 159 160 221 245 address 159 connection 80 input channels 60 170 224 INPUT commands 170 input protection 69 input setup 32 input statistics 35 Instrument Calibration 135 216 Calibration Interval 135 Calibration Services 135 Password 137 Procedure 135 Instrument Status Enable 149 Instrument Status Register 149 integrator gain term 192 ISE 149 151 ISR 149 151 keypad keys 20 Index 3 LogOhms 87 Loop 1 4 71 connection 80 control modes 39 range selection 39 setpoint entry 29 setup 36 Loop 2 36 connection 80 control modes 39 setpoint entry 29 LOOP commands 186 loop status 27 manual control mode 38 39 73 197 198 Multiplier field 52 63 86 NTC resistor 61 O
174. nput channel See the section on Temperature Displays gt 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 32 will store up to six PID Tables They are numbered zero through five 40 Cryo con Model 32 Heater Resistance Enumeration Default 250 The heater resistance field is an enumeration that sets the value of the heater load resistance Choices are 500 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 Heater Ranges table above 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 and 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 minut
175. nt 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 will be asserted Temperature is assumed to be in the display units of the selected input channel There is a 0 25K hysteresis in the assertion of a high or low temperature alarm condition Command Syntax INPUT lt channel gt ALARM LOWEST lt temp gt Where lt channel gt is the input channel indicator and lt temp gt is the alarm setpoint temperature Temperature is a floating point string that may be up to 20 characters Query Syntax INPUT lt channel gt ALARM LOWEST Query Response lt temp gt Where lt channel gt is the input channel indicator and lt temp gt is the temperature setting of the low temperature alarm for lt channel gt Temperature is reported to the full precision of 32 bit floating point Command Example INP A ALARM LOW 100 5 Sets the low temperature alarm setpoint for input channel A to 100 5 Query Example INP B ALARM LOW Example Response 25 43210 If the display units setting for input channel B are Celsius this response is also in units of Celsius Short Form INP lt channel gt ALAR LOW 178 Cryo con Model 32 INPUT ALARM HIENA Alarm High Enable Sets or queries the high temperature alarm enable for the specified input channel An alarm must be enabled before it can be asserted
176. nt is the ratio between the sensor resistance and an internal calibration standard resistance This effectively cancels the DC drift and electronic noise associated with the internal voltage reference and constant current source circuitry Resistor sensors may use any of the three constant current settings Constant Voltage Sensor Excitation A unique feature of the Model 32 is the constant voltage excitation mode where current applied to the sensor is autoranged in order to maintain a constant RMS voltage level across the sensor A constant voltage excitation is necessary since the resistance thermometers used below about 10K exhibit a negative temperature coefficient Therefore a constant voltage measurement will reduce the power dissipation in the sensor as temperature decreases By maintaining a low power levels sensor self heating errors that occur at very low temperatures are minimized In the constant voltage mode sensor excitation is a 1 25Hz bipolar square wave This provides DC offset cancellation without loss of signal energy 60 Cryo con Model 32 Available voltage selections are 10 0mV 3 33mV and 1 0mV RMS The maximum and minimum sensor resistance that can be read is a function of the selected voltage bias Power dissipation in the sensor is computed by 2 V _ bias P sensor Resistance Range Table Voltage Mi Max Bias Resistance Resistance n 3 33mV 250KQ 1 0mV 100KQ Table 17 Voltag
177. nt to 8 Seconds Query Example SYSTEM DISTC Example Response 2 Which indicates that the display filter has a 2 Second time constant Short Form SYST DIST 158 Cryo con Model 32 SYSTEM ADRS GPIB address Selects the address that the IEEE 488 2 remote interface will use The address is a numeric value between 1 and 31 The factory default is address 12 The addresses assigned to units must be unique on each GPIB bus structure Multiple units with the same address on a single bus structure will cause errors Command Syntax SYSTEM ADRS lt adrs gt Where lt adrs gt is the desired unit address The IEEE 488 2 interface on the Model 32 will be re initialized using lt adrs gt as it s address Query Syntax SYSTEM ADRS Query Response lt adrs gt Command Example SYSTEM ADRS 14 Sets the Model 32 IEEE 488 2 address to 14 Query Example SYSTEM ADRS Example Response 12 Indicates that the current GPIB address is 12 Short Form SYST ADRS 159 Cryo con Model 32 SYSTEM REMOTE Select Remote Interface Queries or selects the port that the Model 32 will use for all remote communication Available ports are GPIB for the IEEE 488 2 port RS232 for the RS 232 port Command Syntax SYSTEM REMOTE lt port gt Where lt port gt is the remote port selection The Model 32 will first disable all remote ports then initialize and re enable the selected port This command can be used as a port reset
178. nter key will select curve generation with a single point near 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 107 Cryo con Model 32 CalGen Menu 2 point Diode Sensor The exact temperature at a point near 300K is entered here Note if CalGen 1 E300 000 Capture HH hasnotbeenusedonthis channel before the word Capture will appear Otherwise the last captured sensor reading will appear Pressing the Enter key will capture the E z i existing unit reading and associate it 2 Unit 0 98257V e with the 300K point The value will be displayed on line 1 above The exact temperature at a point near 3 E 77 000 Capture 77K is entered here Pressing the Enter key will capture the E J existing unit reading and associate it 4 Unit 1 28257V with the 77K point The value will be displayed on line 3 above a Pressing the Enter key will initiate the 5 New Curve 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 measur
179. nterface 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 1 31 Secondary Address None Timeout 2S Terminate Read on EOS NO Set EOI with EOS on Writes YES EOS byte N A Table 36 Recommended GPIB Host Setup Parameters 145 Cryo con Model 32 RS 232 Configuration The user can select RS 232 Baud Rates between 300 and 38 400 The factory default is 9600 The Baud Rate can be changed from the instrument s front panel by using the SYS 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 uses a New Line or Line Feed character as a line termination In the C programming language this character is in or hexadecimal OxA When sending strings to the controller any combination of the following characters must be sent to terminate the line 1 Carriage Return Hex OxD 2 Line Feed In Hex OxA 3 Null 0 The controller will always return the n character at the end of each line r 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 c
180. ntry 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 will upload or download curves that can be created by a text editor The entry of a sensor calibration curve is essentially identical to the process used to enter PID Tables The procedure for entering or editing a calibration curve is summarized as follows 1 The sensor s calibration curve is accessed from the Sensor Setup menu detailed above 2 Data points in the selected curve are entered by first entering the entry index then values for sensor readings vs corresponding Temperature 3 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 either the temperature field The first four characters of a Calibration Curve Menu show the two digit sensor index followed by either the sequence gt gt 52 Cryo con Model 32 Calibration Curve Menu 1 18 gt gt IX 123 Sets the current index to an entry within the current table Values are 0 to 159 When the Enter key is pressed the following lines will display any data corresponding to the selected entry 2 18 gt gt T 23
181. of pre tuning is to use PID control with a small 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 will reduce the offset amount When P is too large the system will oscillate 89 Cryo con Model 32 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 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 by 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 will be 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 32 must be in Control mode 2 Both the output power and the process tempe
182. om 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 Power up in Control Mode Default Off The SYS 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 SYS Auto Ctl is ON the controller will power up then after ten seconds will automatically engage the control loops 46 Cryo con Model 32 Remote l O transactions The last two lines of the SYS menu are the Remote I O input and output lines These are used to assist in debugging programs that use the controller over one of its remote interfaces The remote input line gt shows the last complete command received and parsed by the controller The remote output line lt shows the response that the command generated 47 Cryo con Model 32 PID Tables Menu The Model 32 can s
183. om in on the temperature You should be able to see the signature with the chart set to the base temperature plus or minus about 0 5K In order to see the cooler signature you will need to set the Sync Filt Taps field to zero This will disable the removal of the signature From here you can enter various values in order to see the affect of the synchronous filter Cryo con Model 32 Shown here is an example of a Cryomech PT403 pulse tube refrigerator with 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 7 taps 41 Cha Auto 20 Manual In most cases a tap setting may be found that completely eliminates the signature 97 Cryo con Model 32 Using an external power booster Some systems require more power than the Model 32 can provide or require a higher power secondary control loop An auxiliary DC power supply or amplifier can be used for this purpose Programmable power supplies that can be programmed by an input voltage or current can be interfaced to either control loop of the Model 32 Both control loops of the Model 32B are unipolar current source outputs This means that they will not have the zero voltage drift problems that bipolar voltage source outputs exhibit Since both loops are current source outputs a programming resistor may be required to develop the voltage needed by the booster supply To us
184. om the current barometric pressure Once the dialog box has been completed click OK to proceed To finish the process you will be prompted to save the modified calibration curve to a file Once complete the file can be transferred to any Cryo con instrument 128 Cryo con Model 32 The Vapor Pressure Calculator The Vapor Pressure Calculator is a convenient aid that computes the actual temperature of most cryogens given the current barometric pressure It can be launched directly off of the utility disk by executing Vapor Pressure Calculator exe or from the CalGen dialog as shown above A typical calculation is shown here Vapor Pressure Calculator x Substance Water Pressure 760 Torr Temperature Units K Temperature 373 1521 K You must select the Substance from a drop down list and then select the barometric pressure and temperature units 129 Cryo con Model 32 Substance selections are shown here Vapor Pressure Calculator Heliurn 4 a EER EJ 130 Cryo con Model 32 Downloading Instrument Firmware A primary feature common to all of Cryo con s instruments is the ability to download new firmware Firmware must be matched to the product s model number and hardware revision level For that reason please contact Cryo con via e mail or telephone for the most recent firmware Firmware updates include the addition of new features as well as b
185. on Diode GaAs Diode 1 0mA to NTC resistors including Ai 10 to IMQ Ruthenium Oxide Cernox NTC resistors including R250K10UA 250KQ CI 101 A Ruthenium Oxide Cernox NTC resistors including R125K10UA 125KQ Cl 10nA Ruthenium Oxide Cernox NTC resistors including R62K10UA 62KO Cl 101A Ruthenium Oxide Cernox R16K10UA PTC NTC Resistors R8K10UA PTC NTC Resistors R6K100UA 1004A Platinum 1000 R2K100UA 100uA Platinum 1000 Table 19 Supported Sensor Configurations Bias types are Cl Constant Current sensor excitation Cryo con Model 32 CV Constant Voltage sensor excitation Voltages of 10 0mV 3 3mV and 1 0mV RMS may be selected Excitation current autoranges from 1 0mA to 10nA in order to maintain the selected voltage Silicon Diode Sensors Silicon Diode sensors 2 volt diodes are configured with a 10uA current source excitation and a 2 5 Volt unipolar input voltage range Gallium Arsenide Diode Sensors Gallium Arsenide Diodes or 6 Volt Diodes can be used down to a minimum temperature of about 25K This limitation is imposed by the fact that the controller s maximum input voltage is 2 25 Volts Gallium Arsenide sensors do not fit standard calibration curves therefore the user must provide a sensor specific curve before using this type sensor To use diodes Gallium Arsenide select the Diode input sensor type PTC Resistor Sensor RTDs The Model 32 supports all types of Positive Tempera
186. on reaching the new setpoint ramp mode will be 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 SettheRamp 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 a ramping Control Mode There are two types 1 RampP which will perform a ramp using the current PID parameters and 2 RampT which will ramp using PID parameters derived from a specified PID Table The RampP mode will perform a ramp and then perform temperature regulation using the standard PID mode The RampT function will perform a ramp then perform regulation using the PID Table control mode 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 will terminate 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
187. on to a 500 load while setting a 250 load will result in only one half of the indicated heater power being dissipated 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 can be detected and their corresponding alarms asserted The temperature of the internal heater heat sink is continuously monitored used to generate over temperature fault conditions that will result in shut down of the control loop 71 Cryo con Model 32 The absolute resolution of output heater current is 0 0015 of full scale Sixteen bits However this resolution is significantly extended through the use of a dither signal that is applied to the Digital to Analog Converter and averaged by analog filtering in the output stage The resulting output is an interpolation between the available quantization levels See Appendix C Application Note on Signal Dither for details c 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 curren
188. ons 35 enable 33 179 high setpoint 33 hysteresis 35 hysterisis 176 177 178 latched 33 35 LED 23 low setpoint 33 output 74 sensor fault 181 Index 1 setpoint 33 177 178 180 setup 35 status 20 176 viewing 30 ASCII 147 154 autocalibrate 161 222 Autotune 73 211 212 213 214 215 229 remote commands 210 Autotuning 88 modes 89 pre tuning 89 setup 90 Beep command 158 bias voltage selection 35 CALCUR commands 200 CALDATA commands 207 CalGen 35 69 102 105 115 126 Diode Sensor 107 Pt Sensor 109 setup 105 thermocouple 109 calibration curve 52 100 115 202 205 206 227 CONFIG commands 167 constant voltage 60 CONTROL command 155 157 CONTROL key 11 Cryo con Model 32 Control LED 23 control type selection 39 control types 188 CRV 115 118 Cryocooler synchronous subtraction 95 thermal signature 95 current excitation 60 Curve 340 115 118 data logging 115 123 configuration 123 Derivative gain 38 differentiator gain term 193 Display brightness 45 configuration 24 31 Dual Input Status 31 Dual Loop Status 31 Loop Status 31 resolution 25 45 165 222 Statistics 31 time constant 44 Dither 72 Electrical Isolation 69 Enclosure 82 dimensions 59 weight 59 ENTER key 20 enumeration fields 20 Index 2 ESC key 20 ESE 150 151 153 221 ESR 150 153 221 Factory Defaults 5 restoring 15 firmware forci
189. ons and press the Enter key to make the selection Press the key to go down to the Sen filed Here you will use the k or 4 key 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 four user installed selections will be shown The default name for these is User Sensor N However 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 and the Home key can be pressed to return to the Home Status display The exceptions are NTC resistor sensors that use constant voltage AC excitation With these types of sensors you will need to scroll down to the Bias Voltage field and select the desired constant voltage excitation level r Note NTC resistor sensors require the selection of a Bias Voltage Selections are 10mV 3 3mV and 1 0mV Generally 10mV works well for most sensors down to about 1K Below that the lower settings may be used to minimize errors from sensor self heating However use of a lower voltage limits the maximum resistance range and significantly increases measurement noise Once sensor configuration is complete review the section on Sensor Connections to connect the sensor to the instrument 85 Cryo con Model 32
190. or 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 k or 4 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 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 34 Cryo con Model 32 CalGen Selection of the CalGen field initiates the calibration curve generator feature This feature is described in the section CalGen Calibration Curve Generator Setting a Temperature Alarm The Alarm lines are used to setup alarm conditions The Model 32 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
191. ote 1 0 problems Symptom Condition Can t talk to RS 232 Possible causes interface Ensure that the RS 232 port is selected Press the Sys 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 Sys 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 Possible causes RS 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 with the shield connected to a metal backshell at both ends Don t send reset RST commands to the controller before reading
192. own 25 Cryo con Model 32 Temperature units are selected in the individual input channel setup menus ChA or ChB Temperature Units may be K C or F When Sensor Units S is selected the raw input readings are displayed These will be in Volts or Table 7 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 shorted CES 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 characters is shown c 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 26 Cryo con Model 32 Loop Status Displays When the Model 32 is not controlling temperature the status of the Loop output is shown The first character of the Loop Status Display is always the loop number which will be either a superscripted 1 or 2 corresponding to Loop 1 or Loop 2 The Loop number will be followed by the heater status as follows 1 OFF Indicates that heater output is functional and the control loop is off or disabled 1 OFF Low For the primary
193. perature Controller Esc ChA A123 456K B321 234K WOOD 1 15 HI 26510 Auto Sensors Table Tune o S Mt Power Stop Control Home Enter Display Alarm Set Pt CI GORE Figure 2 Model 32 Front Panel Layout The Keypad Function Keys The Function Keys on the Model 32 are Power Stopj Control Home and Enter as shown here Power Sto Control Home Enter CO 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 Cryo con Model 32 c Note The Model 32 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 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 both off To enable or disable an individual loop go to the Control Loop Setup menu and select the desired Type
194. pment 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 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 VIT Guy D Covert President Cryogenic Control Systems Inc October 15 2005 231 Cryo con Model 32 232 Cryo con Model 32 Appendix A Installed Curves Factory Installed Curves The following is a list of factory installed sensors and the corresponding sensor index ISENIX 233 Cryo con Model 32 isenix Name Description 0 None Input disabled 4 Cryocon S700 Cryo con 700 series Silicon Diode Range 1 4 to 380K 10uA constant current excitation 2 LS DT 670 Lakeshore Silicon Diode Curve 11 for DT 670 series diodes Range 1 4 to 500K 10uA constant current excitation 3 LS DT 470 Lakeshore Silicon Diode Curve 10 for DT470 series diodes Range 1 4 7 to 495K 10pA constant current excitation 4 CD 12A Diode Cryo Industries CD 12A Silicon Diode Range 1 4 to 325K 104 A constant current excitation A Scientific Instruments Inc 41
195. pped 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 240 Cryo con Model 32 Symptom Condition Autotune indicates a status of Abort or Fail Autotune will only abort if the control loops are not engaged or there is an invalid temperature reading on the control input channel If
196. pt Headers There are three types of headers Simple Command Compound Command and Common Command Simple command headers contain a single keyword CONTROL and STOP are examples of single command headers The syntax is lt function gt lt terminator gt 147 Cryo con Model 32 When parameters indicated by lt data gt must be included with the simple command header for example INPUT CHA the syntax is lt function gt lt white space gt lt data gt lt terminator gt Compound command headers are a combination of two or more keywords The first keyword selects the subsystem and the last keyword selects the function within that subsystem Sometimes you may need to list more than one subsystem before being allowed to specify the function The keywords within the compound header are separated by colons For example SYSTEM AMBIENT To execute a single function within a subsystem use the following lt subsystem gt lt function gt lt white space gt lt data gt lt terminator gt Command headers control IEEE 488 2 defined functions within the instrument such as clear status etc Their syntax is lt command header gt lt terminator gt No space or separator is allowed between the asterisk and the command header CLS is an example of a common command header To execute more than one function within the same subsystem a semi colon is used to separate the functions lt subsystem gt lt function gt lt w
197. ramming resistor that can dissipate at least 10 Watts Therefore this resistor will get very hot during normal operation 2 Connect the Loop 2 output to the booster supply s programming and set up the supply according to the manufacturer s documentation Some inexpensive booster supplies that have been used with the Model 32 are Tenma 72 2005 18V 3A 159 2005 price Tenma 72 2020 30V 3A 219 2005 price Tenma 72 2015 60V 1A 229 2005 price 99 Cryo con Model 32 Using Thermocouple Sensors Thermocouple sensors have low sensitivity and are very susceptible to electrical noise Therefore they are often difficult to apply In order to obtain the best possible measurement accuracy the recommendations given here should be carefully applied Direct Connection The Model 32 supports direct connection to Thermocouple sensors by using a software based Cold Junction Compensation scheme as follows 1 The sensor input connection on the rear panel of the instrument is thermally anchored to a temperature sensor that is used for Cold Junction Compensation 2 The Cold Junction Temperature is continuously monitored and converted to a Cold Junction Voltage by a performing a reverse lookup of the sensor s calibration curve 3 When a sensor reading is taken the Cold Junction Voltage is subtracted from the measured voltage The result is used to compute actual sensor temperature by using a forward lookup on the s
198. ramping mode without exiting the control loop This 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 93 Cryo con Model 32 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 A ramping control mode must also be set Ramping modes are RampP or RampT These modes are also selected in the Control Loop Setup menu 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 don
199. ransferred between the PC and the instrument by using the Calibration Table menu To download a curve send it from the PC to the instrument either select Sensor Curve Download from the shortcut bar or Operations gt Sensor Curve gt Download ES Look in a Model 34 e ex Ed El aufeD cr crw El pt1003902 crw Gil TCTypeT crw E CryocalD3 crw El PT1K375 crv Ea curve10 cry El PT1K385 crw Bi Curvell crv El 51410 crw CX1O3DE1 crv E TCTypeE crv PT100385 crv E TCTypeKk crv File name Files of type Curve Files crv 340 y Cancel Z from the main menu This will cause a file selection dialog box to appear as follows From this screen the desired calibration curve is selected Cryo con calibration curves have the file extension of CRV Lakeshore curves with the extension 340 may also be selected Scientific Instruments txt files may be downloaded by first selecting a file type of and then selecting the desired calibration curve file Cryo con CRV files are ASCII text files that may be edited by any text editor 118 Cryo con Model 32 After selecting the file and clicking on Open the selected file will be read and the Edit Curve Header dialog box will appear This box contains information extracted from the curve file header that can be modified if desired before the curve is downloaded xl Sensor Name TCAuFe pct Sensor Type reso y Multiplier 1 Unit Volts
200. rature must be stable The user must stabilize 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 32 can be manually tuned using sensor units but autotuning cannot be performed 90 Cryo con Model 32 Autotune Menu Sets the loop number for autotuning Each control loop must be tuned 1 tAutotune Loop 2 hy separately Choices are Loop 1 and Loop 2 The selected loop is displayed in all following lines of this menu Sets the maximum power delta allowed 2 ZAT DeltaP 20 H during the tuning process Value is a percent of full scale output power for the selected loop Sets autotuning mode Choices are P 3 ZAT Mode PI ky PI or PID PI is recommended for most systems Sets the autotune timeout in seconds If 4 ZAT Timeout 180S HE the process model has not converged within this time tuning is aborted Real time display of the temperature on 5 2308 112K the input channel being tuned Pressing Enter will initiate the autotune 6 ZAT GO e sequence 7 ZAT Idle Autotune status Display only Proportional gain term generated by 8 ZAT P autotune This field will be blank until a succes
201. rmocouple optional range requires voltages of 0 075 and 0 075 Volts The test equipment recommended for complete calibration is a Fluke 5700A DMM calibrator The Basic Calibration Sequence You must first connect the Model 32 to a computer via the RS 232 Serial or IEEE 488 GPIB interface and then run the Utility Software provided with the controller The Utility Software must be version 7 4 2 or higher From the start up menu of the Utility Software click the Connect button in the bottom of the Short Cuts toolbar The software will connect to the instrument and display the connection status below the button In case of an error please correct the port connection settings and try again From the main menu select Operations gt Unit Cal The program will read the current calibration values from the instrument and display a calibration screen as shown below All calibration operations can be performed by using this screen 136 Cryo con Model 32 x Si Diode V Si Diode Im amp DC 10044 DC 1044 DC 1044 AC 10044 AC ima AC T of MET Steps r Calibration Reuts Channel la H Current Step Calibrating CHA Silicon Diode Volt Calibrate Ai 1 9 Apply 1 9 and enter actual volt Status Curent pi Capture Gan a 05 Apply 0 5 and enter actual volt Offset uo 4 Capture Abor Cancel Figure 8 Instrument Calibration Screen c Note Newer Cryo con instrum
202. rms may be viewed by pressing the Alarm key A display like this one will be shown HAlarm LO L Alarms are set for each input channel using the Input Channel Setup menu described below EAlarm HI 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 asserted until it is manually cleared by the user c 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 30 Cryo con Model 32 The Display Configuration Menu The display configuration menu is accessed by pressing the Display key When accessed the menu will appear as a list of possible configurations The cursor indicated by a M character will be located at the current configuration Use the dk and keys to move up and down the list Display configurations are Default Input channel status Displays temperature of both input channels and the status of any control loop assigned to the inputs Detailed status of control loop 1 Temperature of controlling input channel set point heater status
203. s for resistor sensors Input Channel Statistics INPUT MINIMUM Queries the minimum temperature that has occurred on an input channel since the STATS RESET command was issued INPUT MAXIMUM Queries the Maximum temperature that has occurred on an input channel since the STATS RESET command was issued INPUT VARIANCE Queries the temperature variance that has occurred on an input channel since the STATS RESET command was issued INPUT 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 STATS RESET command was issued INPUT OFFSET Queries the input channel statistics OFFSET is the offset of the best fit straight line passing through all temperature samples that have been collected since the STATS RESET command was issued STATS TIME Queries the time duration over which input channel statistics have been accumulated STATS RESET Resets the accumulation of input channel statistical data 225 Cryo con Model 32 Command Function LOOP Commands LOOP SOURCE Sets and queries the selected control loop s controlling input LOOP SOURCE channel LOOP SETPT Sets and queries the selected control loop s setpoint LOOP SETPT LOOP TYPE Sets and queries the selected control loop s control type LOOP TYPE LOOP 1 RANGE LOOP 1 RANGE
204. s or perform any unauthorized modification to the product For service or repair return the product to Cryo con or an authorized service center Cryo con Model 32 Contents Preparing the controller for USE nana crcnnr narco 1 Supplied Items aiii aid alee Et 1 Verify the AC Power Line Voltage Selection i 1 Apply Power to the Controller 1 Installation iii Lie 3 General iio E E 3 Rack Mounting arrneo aa a ares iaie i RNA r rriei 3 Initial Setup and Configuration canon rnnna no 4 Factory Default SEetup i 5 Model Identification i 6 Ordering Information i 6 Options and Accessories tennen 8 Instrument Accessories cnc nana ncncnnnnncccnnns 8 Cryogenic AccEessories nn nr nnnnnnnrrnnn narran 9 Returning Equipment nesteet 10 A Quick Start Gude eana aenieei ia 11 A Quick Start Guide to the User Interface 11 The Home Status Display ii 11 Accessing the heater Setpoint i 11 Configuring a temperature SEnSor i 11 Configuring the Loop 1 Output 13 Configuring the Loop 2 Output 15 Restoring Factory Defaults oooooonnncccnnnnicccnnnococcnnnorccnnonarrc cnn 15 Forcing a Firmware Download non 16 Front Panel Operation
205. sconnect 8 OTD T 300 000 setpoint temperature r Selects the port for remote I O 9 RIO Port RS232M Selections are RS232 or GPIB Sets GPIB I O address It is a numeric 10 RIO Address 12 HE entry with a range of 1 to 31 Default is 12 5 Sets RS 232 port baud rate Selections 11 RIO RS232 19K M range from 300 to 38K baud Advanced configuration Number of taps 12 Sync Filt Taps O78 inthe synchronous filter Normally set to a value of 7 13 SYS AC Line 60 K AC line frequency Select 50 or 60Hz Power Up Mode Off for normal operation On to engage the control 14 SYS Auto Ctl Off loops 10 seconds after power has been turned on 15 gt Remote I O Last command received 16 lt Remote I O Last response Table 12 System Functions Menu Display Time Constant Enumeration Default 2 Seconds The SYS 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 44 Cryo con Model 32 Display Resolution Enumeration Default 3 The Display Resolution line SYS Display RS is used to set the temperature resolution of the front panel display Settings of 1 2
206. se of a mechanical stripper scrapping and passing the wire over a low level flame Ribbon Cable Color Codes V Clear V Green I Black l Red Thermocouple Sensor Connections Thermocouple sensors require the factory installed thermocouple option All thermocouple connections must be made at the sensor input connector since this connector is thermally anchored to an internal sensor that is used for Cold Junction compensation Thermocouple sensors are connected to the Model 32 by use of the special connector provided with the controller Sensor connection is made at the screw terminals Proper polarity of the sensor wires is required Polarity is marked on the input connector and a summary of common thermocouple polarities is given in the table below The input connector should have its backshell and rubber grommet installed in order to prevent local air currents from generating errors in the cold junction circuitry It is recommended that the Thermocouple sensor be electrically isolated or floating from any surrounding circuits or grounds This will ensure the highest possible measurement accuracy Figure 6 Thermocouple Input Connector 79 Cryo con Model 32 Additional discussion on Thermocouple and grounding issues can be found below in the Using Thermocouple Sensors section below Type Color Terminal Terminal E Purple Chrome Constantan K Yellow
207. se of various voltage and resistance standards in order to generate calibration factors for the many measurement ranges available Calibration is Closed Case There are no internal mechanical adjustments required The Model 32 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 Calibration of a measurement range is the simple process of generating an offset and gain value However since there are several input ranges available on each sensor input the process can be time consuming Caution Any calibration procedure will require the adjustment of internal data that can significantly affect the accuracy of the instrument Failure to completely follow the instructions in this chapter may result in degraded instrument performance The Cryo con utility software used in this procedure will first read all calibration data out of the instrument before any modifications It is good practice to record these values for future reference and backup Cryo con Calibration Services When the controller is due for calibration contact Cryo con for low cost recalibration The Model 32 is supported on our automated calibration systems which allow Cryo con to provide this service at competitive prices Calibration Interval The Model 32 should be calibrated on a regular interval determined by the measurement accuracy requirements of your appl
208. setups can be named for user convenience The CONFIG NAME command sets and queries the user configuration names Command Syntax CONFIG lt ix gt NAME lt name gt Where lt ix gt is the index number of the desired instrument setup Values may be 0 through 3 lt name gt is the desired name string and is a maximum of 15 ASCII characters Command Example CONFIG 3 NAME Product Alpha This assigns the name Product Alpha to instrument setup 3 Query Syntax CONFIG lt ix gt NAME Query Response lt name gt Where lt name gt is the temperature of the internal heater output stage s heat sink in Celsius Query Example CONFIG 0 NAME Example Response Dewar Two Short Form CONFIG NAM 167 Cryo con Model 32 CONFIG SAVE Save User Configuration Saves an the current instrument setup to a user setup Command Syntax CONFIG lt ix gt SAVE Where lt ix gt is the index number of the desired instrument setup Values may be 0 through 5 Command Example CONFIG 1 SAVE Saves the controller s current setup to user setup 1 Short Form CONFIG SAV CONFIG RESTORE Restore User Configuration Restores a previously stored user instrument setup Command Syntax CONFIG lt ix gt RESTORE Where lt ix gt is the index number of the desired instrument setup Values may be 0 through 5 Command Example CONFIG 0 RESTORE Restores the controller s setup from user setup 0 Short Form CONFIG REST 168 Cryo co
209. sful autotune is completed Integral gain term generated by 9 ZAT I autotune This field will be blank until a successful autotune is completed Derivative gain term generated by 10 ZAT D autotune This field will be blank until a successful autotune is completed Pressing cause the controller to y transfer the generated PID coefficients 11 AT Save Exit to the selected loop initiate control with the new parameters and exit to the Home Operate Display Table 32 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 will allow use full scale power increments A value of 20 will use 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 91 Cryo con Model 32 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 c 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 concer
210. sors Table Tune ChA Go to the Input Channel A setup menu Loop 2 7 CJ a ChB Go to the Input Channel B setup menu Display Alarm SetPt Loop 1 Go to the Loop 1 or primary heater output se setup menu Go to the Loop 2 or secondary heater output 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 Display Sys Go to the System Functions menu This includes fields for Remote Input Output Display filters and the Over Temperature Disconnect feature Go to the Display setup menu This allows configuration of the front panel display from a list of options Cryo con Model 32 Alarm Go to the Alarm Status menu Set Pt Set the setpoint values for both control loops The Selection Keys and Enumeration Fields Enumeration fields are display fields where the value is one of several specific choices For example 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 An enumeration field is always indicated by the M character in the last column of the
211. splay is similar to the Dual Input Status display described above However on this display control loop 1 is always on the left side and loop 2 is always on the right Channel A and B Statistics Display The Channel A and B statistics displays show the selected input channel temperature the slope of the temperature history the minimum and maximum temperatures E17 4567K M 1 0322 The slope of the temperature history gt 18 0022K lt 16 0322K M is given in Display Units per Minute In this example Display Units are Kelvin Temperature Displays A typical Input Channel Temperature Display is shown here It consists of the input channel designator a Temperature reading and the current temperature units The input channel designator is a superscripted A or B The temperature is a seven character field and is affected by the Display Resolution setting in the Sys menu This setting H87 4567K 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 display 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 beyond the sensor s actual resolution If the Input Channel has been disabled a blank display is sh
212. stants 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 this case the Integral t
213. t Connection to the heater output is made on the rear panel using the banana plug block provided Caution The Model 32 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 SYS Auto Ctl function in the System Functions menu section Control Loop 2 Secondary Heater Output For a standard Model 32 control loop 2 is a voltage output with a 6000 output impedance Range is zero to 10 0 Volts In the Model 32B control loop 2 is a constant current source similar to the Loop 1 heater It has a single output range of zero to 450mA and a compliance of 25V This will result in an output power of 10 Watts into a 500 load The absolute resolution of Loop 2 is 0 0015 of full scale Sixteen bits However this extended through the use of a dither signal See Appendix C Application Note on Signal Dither for details Connection to the Analog Output is made on the rear panel using the pluggable terminal block provided 72 Cryo con Model 32 Control Types There are four control types available in the Model 32 They are Manual PID PID Table and Ramp All modes are available on both 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
214. t They should not be included when using the GPIB interface The maximum number of entries in a curve is 200 and the minimum is 2 lt index gt is a numeric index to the user calibration curve list Values are 1 through 4 in the Model 32 and 1 through 12 in the Model 34 and 62 lt curve name gt is a name to be assigned to the calibration curve It is a minimum of 4 and a maximum of 15 ASCII characters lt sensor type gt is from the following list Diode ACR 31kR 3 1kR 312R 625R TC80 TC40 and None If the sensor type cannot be identified Diode is used Sensor Types are described in the section on Supported Sensor Configurations above lt multiplier gt is the temperature coefficient and curve multiplier If this field cannot be identified a value of 1 0 is assumed This field is described in the section Sensor Setup Menu above lt curve units gt is the units of the curve Choices are OHMS VOLTS or LOGOHM The last entry in a calibration curve must be a single semicolon Query Syntax CALCUR lt index gt Query Response lt calibration curve gt Short Form CALC 202 Cryo con Model 32 PIDTABLE commands The PIDTABLE commands are used to transfer PID tables between the Model 32 and the host controller PID Tables are referenced by their index number which is between 0 and 5 Table data corresponding to a specific index may be identified using the PIDTABLE query There is a maximum of 16 entries
215. t A setup menu 2 ChB Sensor input B setup menu 3 LOOP 1 Primary control loop setup Loop 1 4 Config User configuration save and restore 5 Sys System functions menu 6 Loop 2 Loop 2 setup menu 7 Sensors Sensor data and calibration curve menu 8 PID Table PID table menu 9 Auto Tunel Autotune menu Table 6 Keypad key functions 22 Cryo con Model 32 The LED indicators and Audible Alarm There are three LED indicators located just below the main display as shown here Control Alarm Remote Power Control Home Enter The Green 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 has been triggered To clear the alarm the enabled event that is asserting the alarm must be disabled 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 23 Cryo con Model 32 The VFD 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 the instrument s menu tree by pressing the Home key The list of display configurations is accessed by pressing the Display key Dual Input Status default Loop 1 Status Loop 2 S
216. t Firmware gt Download from the Utility Software s main menu If the Download item is grayed out you must exit the utility software and re start it with the correct command line switches as noted in the caution above Selecting a firmware download will result in the display of a file selection dialog box as shown below 10 x gt Cryo con Utility Software dloader File Comm Firmware Calibration Table PID Table View DataLogging Help Ce Zl aa m623r10 bin File name Files of type BIN Files bin y Cancel 4 In this dialog box firmware file names are coded as shown below MmmRev BIN Where mm is the Model Number eg 32 34 62 etc and Rev is the revision code in the format XrXX where the lower case r indicates a period character The file extension is always BIN From the file dialog box find and select the desired firmware file Then click on the Open button in order to initiate the firmware download Firmware download will be initiated immediately after the Open button is clicked Once download has started you should not attempt to stop it 132 Cryo con Model 32 When a firmware download has successfully started the VFD display will continuously display the number of records transmitted as shown here There are 1008 records in a complete Record 001 of 502 firmware download The process should Errors 000 take about 15 minutes The PC screen will show a bar graph of progress dur
217. t started Running Autotune is running Complete Autotune successfully completed Failed Unable to generate PID values Abort Aborted by operator intervention Query Syntax lt oc gt AUTOTUNE STATUS Query Response lt status gt Where lt oc gt is the output channel to tune and may be either LOOP 1or LOOP 2 lt status gt is the current status of the autotune process from the above list Query Example LOOP 1 AUTO STATUS Example Response COMPLETE Indicates that autotune has successfully completed and generated values for PID are available Short Form AUT STAT 215 Cryo con Model 32 INSTCAL commands The INSTCAL commands are used to calibrate the Model 32 input sensor measurement circuitry They should only be used in association with the instrument s calibration procedure Instrument calibration requires the use of various transfer standard resistance and voltage references In order to calibrate the Model 32 the calibration mode must first be turned on by using the INST MODE ON command Issuing this command will cause the unit to copy the actual calibration data from flash memory to temporary RAM Further the unit will display raw voltage data that has had the RAM calibration coefficients applied The temporary RAM calibration data is manipulated using the OFFSET and GAIN and TYPE commands for each input channel RAM is copied back to the actual FLASH memory calibration data table using the SAVE command
218. t the current temperature of the Model 32 s internal voltage reference is 25 C Short Form SYST AMB Where AMBIENT is truncated to four characters then to three since the fourth character is a vowel SYSTEM AUTOCAL Automatically recalibrate the input channels This command causes the Model 32 to execute an internal recalibration of both input channels It is useful when the operating temperature has changed significantly The process takes about Y second to complete Autocalibrate should not be executed when the Model 32 is controlling temperature because it may cause the control loops to disengage Command Syntax SYSTEM AUTOCAL Short Form SYST AUT Where AUTOCAL is truncated to four characters then to three since the fourth character is a vowel 161 Cryo con Model 32 SYSTEM HTRHST Heater heat sink temperature The temperature of the Model 32 s internal heater circuit heat sink is continuously monitored and used to initiate the automatic shutdown sequence when a heater fault is detected This temperature may be queried using the SYSTEM HTRHST command Query Syntax SYSTEM HTRHST Query Response lt temp gt Where lt temp gt is the temperature of the internal heater output stage s heat sink in Celsius Query Example SYSTEM HTRH Example Response 62C Indicates that the heat sink is at 62 C Short Form SYST HTRH SYSTEM HOME Display Operate Screen Causes the VFD display on the front
219. tatus Dual Loop Status Ch A Statistics Ch B Statistics Da Select the desired configuration and press the Enter to return to the Home display Dual Input Status Display This is the factory default display It shows the status and current input temperature for both control loops Input channel A is shown on the left and channel B on the right A87 4567K E104 932K The second line of the display 1 15 Hi z 28 10W shows the Loop Status Display Directly above each Loop Status is a temperature for the controlling input channel In the example here Loop 1 is being controlled by input channel A and Loop 2 is being controlled by input channel B Please note that either loop may be controlled by either input The display will be adjusted to show the control loop directly below the controlling input channel The next example shows the control inputs reversed Loop 1 controlling in the low power range and Loop 2 off A17 4567K E 24 932K 1 15 Low z Off 5V 24 Cryo con Model 32 Loop 1 and Loop 2 Status Displays These displays show the current status of a selected single control loop Information includes the E17 4567K 30 10W controlling input channel 17 0000K temperature setpoint heater status and heater bar chart In the example shown here for Loop 2 the loop is controlling from input B with 30 output power and the setpoint is 17 0000K Dual Loop Status The Dual Loop Status di
220. that this oscillation does not cause damage Enable the Over Temperature Disconnect feature of the controller if you are concerned about 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 your equipment Set initial PID values of Pgain 0 1 Igain 0 and Dgain 0 2 Engage the control loops by pressing the Control key 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 Setthe PID values according to the following table Control l 3 Pgain Igain Dgain Type P only 0 5 Kc 0 0 PI only 0 4 Kc 0 8 Tc 0 PID 0 6 Kc 0 5 Tc 0 85 Tc 252 Cryo con Model 32 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 c 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 Tun
221. the operator and surrounding area Indoor use only Altitude to 2000 meters Temperature for safe operation 5 C to 40 C Maximum relative humidity 80 for temperature up to 31 C decreasing linearly to 50 at 40 C Power supply voltage fluctuations not to exceed 10 of the nominal voltage Over voltage category Il Pollution degree 2 Ventilation The instrument has ventilation holes in its side covers Do not block these holes when the instrument is operating Do not operate the instrument in the presence of flammable gases or fumes Operation of any electrical instrument in such an environment is a definite safety hazard 84 Cryo con Model 32 Basic Setup and Operating Procedures Configuring a sensor Before connecting a new sensor to the Model 32 the instrument should be configured to support it Most common sensors are factory installed 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 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 F or 4 keys to sequence through the available opti
222. the power up display indicating that defaults have been restored c NOTE Factory defaults may be restored at any time by use of the following sequence 1 Turn power to the Model 32 OFF 2 Press and hold the Enter key while turning power back ON Cryo con Model 32 Forcing a Firmware Download The Model 32 may be powered up in a mode where it will wait for a firmware update via the serial port This is not normally necessary because the Cryo con utility software will set this mode when a firmware update is being processed However if the instrument has crashed during a firmware download or has otherwise become corrupted following this procedure will set the firmware download mode 1 Turn AC power OFF 2 Press and hold the STOP key while turning the AC power back ON Keep the key pressed until the firmware download display is seen The initial firmware download screen Record 000 of 502 is shown here Errors 000 3 Use the Utility Software package to download new firmware over the RS 232 port Instructions are detailed in the section Downloading Instrument Firmware 16 Cryo con Model 32 Front Panel Operation The user interface of the Model 32 Cryogenic Temperature Controller consists of a two line by 20 character Vacuum Florescent display and a keypad All features and functions of the instrument are accessed via this simple and intuitive menu driven interface GRUO con 32 Tem
223. the proper load resistance and output range be selected This is done using the Control Loop Setup menu as follows a Press the Loop 1 key to go to the Control Loop Setup menu for Loop 1 Q Use the up arrow and down arrow keys d and to scroll to the Htr Resistance field An example is shown here 1Htr Resistance 500 a Use the left and right arrow keys P or 4 to select between a 50 Ohm and a 25 Ohm heater and then press the Enter key Q Use the up arrow and down arrow keys 4 and to scroll to the Range field and then 1Range HI N select Hi Mid or Low 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 Low 0 25 Watts 0 50 Watts Table 4 Loop 1 Output Summary Next the control type should be set by scrolling to the Type field and iType PID hy selecting the desired loop operating mode 13 Cryo con Model 32 A summary of control types is given here Type Off Man Table PID RampP Description Control loop is disabled Manual control mode Here a constant heater output power is applied The Pman field selects the output power as a percentage of full scale PID control mode where the PID coefficients are generated from a stored user supplied PID table Standard PID control T
224. tions nono nan r nan rro rar r rr rnrrnnn 31 Table 9 Input Channel Setup Menus 34 Table 10 Control Loop Setup Menus 37 Table 11 User Configurations MENU ii 42 Table 12 System Functions MENU 44 Table 13 PID table Menu i 49 Table 14 PID Table Edit Menu 50 Table 15 Sensor Setup Menu 51 Table 16 Calibration Curve Menu 53 Table 17 Voltage Bias Selections i 61 Table 18 NTC Resistor Measurement ACCUracy ii 61 Table 19 Supported Sensor Configurations 62 Table 20 PTC Resistor Sensor Configuration i 64 Table 21 NTC Resistor Sensor Configuration i 64 Table 22 Sensor Performance for Diodes and Pt Sensors neren 66 Table 23 Sensor Performance for NTC sensors 67 Table 24 Sensor Performance for Thermocouple Sensors 68 Table 25 Loop 1 Heater output ranges eenn 71 Table 26 AC Power Line FuseS nenne neneent 76 Table 27 Input Connector Pin OUt nn nn nnnnnnanannnnnnncnnn 77 Table 28 Dual Sensor Cable Color Codes 78 Table 29 Thermocouple TypesS neen eent 80 Table 30 RS 232 DB 9 Connector Pinout cece eeeeeeeceeeeeceeeeeeetennneaeeees 81 Table 31 Sensor Setup Menu 86 Tabl
225. to 321 Query Syntax INSTCAL lt chan gt OFFSET Where lt chan gt is the input channel indicator Query Response lt offset gt Where lt offset gt is the offset calibration factor Query Example INSTCAL B OFFSET Example Response 23 Indicates that the offset calibration factor for input channel B is 23 Short Form INST lt chan gt OFFS 220 Cryo con Model 32 Remote Command Summary Command Function IEEE Common Commands ESE The ESE command sets and queries the Standard Event ESE Status Enable ESE Register bits ESR Returns the Standard Event SEV register IDN Returns Instrument Identification String OPC Set the operation complete bit in the Standard Event SEV status register when all pending device operations have finished RST Reset the controller Control Loop Start Stop commands STOP Disengage all control loops CONTROL Engage all control Loops Query if the loops are CONTROL engaged SYSTEM commands SYSTEM LOCKOUT SYSTEM LOCKOUT Sets or queries the remote lockout status indicator SYSTEM BEEP Asserts the audible alarm SYSTEM REMLED SYSTEM REMLED Sets or queries the remote LED status indicator on the front panel SYSTEM LOOP Reports the status of the two temperature control loops SYSTEM DISTC SYSTEM DISTC Set or query the display filter time constant Available time constants are 0
226. tore four 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 I D and full scale heater range When controlling in the Table mode the Model 32 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 interfaces 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 line entry 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
227. tors sensors is shown here Taoa Sensor Sensor TC Calibration yP Type Excitation Units Carbon Glass ACR 1 0 to 10 0mV AC LogOhm Germanium ACR 1 0 to 10 0mV AC LogOhm ACR 1 0to 10 0mVAC Logohm Ruthenium Oxide ACR 1 0 to 10 0mVAC LogOhm ACR 1 0 to 10 0mV AC LogOhm Table 21 NTC Resistor Sensor Configuration 64 Cryo con Model 32 Thermocouple Sensors The Model 32 can be ordered with optional thermocouple support Thermocouple inputs on the Model 32 feature e Universal thermocouple input supports all types including user supplied e High accuracy built in Cold Junction compensation e Open sensor detection For more information on using thermocouples please refer to the sections Thermocouple Sensor Connections and Using Thermocouple Sensors 65 Cryo con Model 32 Sensor Performance Summary 1000 Platinum 10000 Platinum 10KQ Platinum DIN43760 DIN43760 DIN43760 Input Configuration 2 5V 10u4A 6250 1 0mA 31250 1004A 16KQ 104A 300K 2 4mV K 800K 0 360 K 600K 3 70 K 300K 390 K Sensor Sensitivity 77K 1 9mV K i sd o li 77K 42Q K 4 2K 30mV K a i 30K 190 K 30K 0 19Q K 30K 1 90 K Sensor Type Silicon Diode 300K 380mQ a 77K 50m0 y 30K 50ma Temperature 300K 6 2mK Measurement 77K 2 8mK Accuracy 30K 9 8mK Measurement 300K 150m0 Resoluti n fe NA 30K 1 8mQ T 300K 4mK emperature 77K 0 5mk Resolution 30K 1 0mK 800K
228. try The temperature of the controlling input is shown on the left and is continuously updated Use the keypad to enter a new setpoint and then press the Enter key Control loop setpoints may also be accessed from the Set Pt key iPgain 25 0000 Proportional gain or P term for PID control llgain 71 0000S Integrator gain term in Seconds for PID control iDgain 71 0000 S Derivative gain term in inverse Seconds for PID control iPman 25 00 Output power as a percent of full scale when controlling in the Manual mode TH RR lInput ChA Control input channel ChA or ChB lRange HI N Output power range For loop 1 this will be HI Mid or Low For loop 2 on a Model 32 it will be10V and for a Model 32B it will be 10W iType PID N Control Type Selections are Off Man PID RampT RampP and Table iPower Limit 100 Power limit as a percent of full scale On loop 1 this limit only applies to the HI range 10 iMax Setpt 1000 00K f Maximum value allowed for the setpoint on this loop 11 1PID Table index O Table number for control in Table mode The Model 32 has six PID tables numbered from zero through five 12 iHtr Resistance 50Q4 Sets the heater load resistance Selections are 25 and 50 13 iRamp 0 10 min Ramp rate in temperature units per minute Table 10 Control Loop Setup
229. ture Coefficient PTC resistive sensors Various combinations of excitation current and full scale input voltage allow the user to trade off accuracy vs sensor self heating The Supported Sensor Configurations table above gives a complete list of combinations that can be selected Standard calibration curves are provided for DIN43760 and IEC751 Platinum sensors While these curves are based on a 1000 sensor they may easily be extended to other resistance values by using the Multiplier field of the sensor setup 63 Cryo con Model 32 A table of recommended setups for various types of PTC resistor sensors is shown here Toe Sensor Sensor TC Calibration yp Type Excitation Units Platinum 1009 R625R1MA 1 0mA AC DC Platinum 10009 R6K100UA 1004A AC DC Platinum 10KQ lt 425K R16K10UA 10uA AC DC Ohms Rhodium lron R125R1MA 1 0mA AC DC Table 20 PTC Resistor Sensor Configuration Ohms NTC Resistor Sensor Devices The Model 32 also supports almost all types of Negative Temperature Coefficient NTC resistive sensors Using AC constant voltage excitation these sensors can be used down to extremely low temperatures Examples of NTC resistor sensors include Ruthenium Oxide Cernox Carbon Glass Germanium and Thermistors Calibration tables may be entered either directly in Ohms or in base 10 Log of Ohms A table of recommended setups for various types of NTC resis
230. ture points Thermocouples Factory installed option on one channel only Input Connector Universal mini spade type thermocouple connector with screw terminals for direct connection to thermocouple wires Input Range 80mV Resolution 0 4pV Electronic Accuracy 1 0uV 0 05 Installed Types K E T and Chromel AuFe 0 07 plus four user supplied curves Cold Junction Compensation Internal enable disable 56 Cryo con Model 32 Control Outputs Number of Loops Two Control Input Either sensor input Loop Update Rate 10Hz per loop Control Type PID table Enhanced PID Ramp or Manual Autotune Minimum bandwidth PID loop design PID Tables Two 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 current source Maximum compliance is 50V Connection Dual Banana Plug 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 500 load Load Resistance 250 or 500 Heaters down to 109 can be used with the 250 range Minimum
231. ually 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 For example if calibration errors for a Type K thermocouple are zeroed at room temperature a reading near Liquid Nitrogen temperatures may have an error of 5K Correction of Calibration Errors over a wide range of temperature can be made by using the Model 32 s CalGen feature Here the controller should be stabilized at 101 Cryo con Model 32 both temperature extremes Then CalGen will generate a new sensor calibration curve that best fits the two points to the actual sensor voltage readings Often CalGen is be done by taking a reading at room temperature then a second reading with the sensor in Liquid Nitrogen Since a thermocouple s sensitivity is relatively constant above room temperature this procedure will give good accuracy over a wide range of temperature 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 Thermocouples have relatively high resistance leads and each lead is made from a different material Therefore they are much more sensitive to AC pickup than sensors using copper wires A ground loop will cause
232. ug fixes Installing a new revision writes to all of the available FLASH type memory in the instrument Therefore existing calibration curves instrument setups and PID tables are reset to factory defaults If user information such as sensor calibration curves has been installed it is recommended that these be uploaded to the computer before new firmware is installed This way they can be re installed after the new firmware Firmware download does NOT erase the instrument s calibration data Note that FLASH memory is inherently non volatile and may be re written in excess of 100 000 times Therefore the user need not be concerned about excessive re writing c Note Firmware can only be downloading using the RS 232 serial interface It cannot be downloaded via the GPIB Therefore make sure that you have a null modem RS 232 cable attached to the controller and that the Utility Software is configured to use RS 232 at a baud rate of 9600 Do NOT use baud rates above 9600 since the firmware update speed is limited by the programming speed of the flash memories Caution To protect the instrument from casual downloads and possible corruption the Utility software must be executed with a command line argument of f for a firmware download and d for a firmware upload The utility disk contains a shortcut named UtilityFD that contains these command line arguments 131 Cryo con Model 32 To download new firmware selec
233. und is connected to the shield of the Power Entry RFI filter then to the instrument s Single Point Ground Since the grounding and shielding scheme depends on having a good quality ground this Earth Ground connection is extremely important Noise and ground loop problems are often traced to how this connection is made If your facility does not provide a building ground it is strongly recommended that one be fabricated Sensor Connection For best performance all sensors connected to the instrument should be electrically isolated floating from any other grounds Sensors used in cryogenic thermometry are often high impedance For example a Silicon Diode temperature sensor will have about 160K ohms of impedance at 5K Because of this a very efficient antenna can develop around the sensor and its connections Requiring these sensors to be floating and providing a low impedance path to ground is the most effective way to eliminate noise pickup from this antenna effect 111 Cryo con Model 32 To ensure that the instrument s grounding scheme is working effectively 1 Make sure that the sensors are floating 2 Make sure that the input cable shields are connected to the connector s metal backshell using the shield clip provided with the connector 3 Make sure that the Third Wire Ground is good quality and not conducting current Control Loops The circuitry in the Control Loop Area provides power to external heater elements
234. up To start the CalGen process either select CalGen from the shortcut bar or select Operations gt CalGen from the main menu This will initiate the process of generating a new sensor curve Using CalGen With Diode Sensors Options for generating Diode calibration curves are 5 One point near 300K The portion of a Diode Sensor curve above 30K will be 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 6 Two points 300K and 77K Here two user specified points are taken to fit the diode curve region above 30K The entire curve is offset to match the 77K point then the gt 30K region is fit to the two points 7 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 8 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 126 Cryo con Model 32 Using CalGen With Resistor Sensors The calibration curve generation procedure for Platinum or other resistor sensors is the same as for the diode However these sensor curves are generated using two user specified points Therefore the selection of the number of points is not required Example CalGen Procedure
235. up Menu To access this menu for input A press the ChA key or for input B the ChB key The first line of this 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 example is shown here A 77 123 K To change the sensor units use the right and left arrow keys Y or 4 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 key This field is ASen Pt100 385 M used to select the actual sensor type In the example shown here the input channel is currently configured for a standard Platinum 100 sensor Use the right and left arrow keys Y or 4 to scroll through the available options When the desired sensor is shown press the Enter key to make the selection A summary of sensor selections is shown here Cryo con Model 32 Sensor Description None Input disabled Cryocon S700 Cryo con S700 series Silicon Diode Range 1 4 to 495K Lakeshore Silicon Diode Curve 11 for DT 670 series diodes Range Boe rere 1 4 to 500K LS DT 470 Lakeshore Silicon Diode Curve 10 for DT470 series diodes Range 1 4 to 495K CD 12A Diode Cryo Industries CD 12A Silicon Diode Range 1 4 to
236. us Filter 95 Configuration 46 Setup 96 Viewing 96 SYS Auto Ctl 46 SYSTEM commands 156 Table control mode 40 48 73 Temperature coefficient 52 history 35 ramp 191 226 units selection 34 variance 35 zones 73 Temperature Sensors Carbon Glass 64 CD 12A 12 234 Cernox 55 62 64 67 236 Diode 62 DT 470 12 234 DT 670 12 234 Gallium Arsenide 63 Germanium 64 NTC 62 NTC resistor 64 Platinum 63 PT100 12 234 PT10K 12 234 PT1K 12 234 Rhodium lron 12 62 234 RO 105 12 234 RO 600 12 234 RTD 12 62 63 234 Ruthenium Oxide 12 62 64 234 S700 12 234 SI 410 12 234 Silicon Diode 62 63 234 Thermistors 64 thermocouple 62 Thermocouple 100 103 106 127 222 Adding new types 100 Calibration Errors 101 Cold Junction Compensation 100 connection 79 100 Errors 100 Grounded 103 Offset Calibration 101 Options 6 types 80 Unit Name 163 User Configurations 19 42 restore 42 save 42 select 42 Cryo con Model 32 Utility Software 87 zone table 48 VFD display 17 Index 6
237. value gt is the generated P gain feedback coefficient Query Example LOOP 2 AUTO PGA Example Response 125 0000 Indicates that the generated P gain term is 125 Short Form AUT PGA 213 Cryo con Model 32 AUTOTUNE IGAIN Integral Gain When an autotune sequence has successfully completed the AUTOTUNE IGAIN command can be used to query the generated I or integrator gain term Query Syntax lt oc gt AUTOTUNE IGAIN Query Response lt value gt Where lt oc gt is the output channel to tune and may be either LOOP 1 or LOOP 2 lt value gt is the generated feedback term in Seconds Query Example LOOP 1 AUTO IGA Example Response 225 0000 Indicates that the generated gain term is 225 Seconds Short Form AUT IGA AUTOTUNE DGAIN Derivative Gain When an autotune sequence has successfully completed the AUTOTUNE DGAIN command can be used to query the generated D or differentiator gain term Query Syntax lt oc gt AUTOTUNE GAIN Query Response lt value gt Where lt oc gt is the output channel to tune and may be either LOOP 10r LOOP 2 lt value gt is the generated D feedback term in inverse Seconds Query Example LOOP 2 AUTO DGA Example Response 22 0000 Indicates that the generated D gain term is 22 Seconds Short Form AUT DGA 214 Cryo con Model 32 AUTOTUNE STATUS Autotune Status Queries the status of the autotune process Return values are Idle Autotune has no
238. ves The software will accept curves in Cryo con CRV Lakeshore 340 or Scientific Instrument s txt format In fact it will read almost any table of temperature vs sensor units 4 Cryo con s CalGen function is implemented This function allows the user to fit an existing sensor calibration curve to one two or three user specified points The result is a high accuracy sensor calibration at low cost 5 Upload and download PID tables to a Cryo con temperature controller These tables can be generated by using a simple text editor and downloaded to the controller Configuration of any of the instrument s remote interfaces Flexible Help interface that documents all instrument remote commands with a cut and paste type interface 8 Interactive Mode provides interactive communication with the instrument over any of the remote interfaces 9 Instrument calibration using a simple step by step menu driven process 10 Uploading and downloading instrument firmware Updates may be obtained on CD or on the Internet Installing the Utility Software From a CD the utility software package does not require installation It can be executed from the CD directly by running the UTILITY EXE program When the software is downloaded off of the Internet it is in a self extracting ZIP format and must first be un zipped onto hard disk 115 Cryo con Model 32 Connecting to an Instrument The desired remote interface connect
239. ware revision level Query Syntax SYSTEM HWREV Query Example SYSTEM HWREV Example Response A Indicating that the instrument s hardware is revision level A Short Form SYST HWR 163 Cryo con Model 32 SYSTEM FWREV Instrument Firmware Revision Level Queries the instrument s firmware revision level Query Syntax SYSTEM FWREV Query Example SYSTEM FWREV Example Response 3 18 Indicating that the instrument s firmware is revision level 3 18 Short Form SYST FWR SYSTEM LINEFREQ AC Power Line Frequency Sets or queries the AC Power Line frequency setting Command Syntax SYSTEM LINEFREQ lt freq gt Where lt freq gt is the AC Power Line Frequency and may be either 50 or 60 for 50Hz or 60Hz Command Example SYSTEM LINEFREQ 60 Sets the AC Power Line Frequency setting to 60 Hz Query Syntax SYSTEM LINEFREQ Query Response lt freq gt Where lt freq gt is the line frequency setting Query Example SYSTEM LINEFREQ Example Response 50 Short Form SYST LIN 164 Cryo con Model 32 SYSTEM DRES Display Resolution Sets or queries the controller s display resolution Choices are FULL The VFD will display temperature with the maximum possible resolution 1 2 or 3 The VFD display will display 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 VFD It does NOT affect the interna
240. when a command error occurs the event summary bit ESB in the Status Byte Register will also be set Query Example ESE Query Response 16 Bit 4 or the Execution Error bit has been enabled All other standard events are disabled ESR Query Event Status Register Query Event Status Register The ESR query returns the contents of the Standard Event SEV status register Query Syntax ESR Query Response lt status gt Where status is a number between 0 and 255 153 Cryo con Model 32 IDN Query unit Identification Query unit identification string The IDN Query will cause the instrument to identify itself The Model 32 will return the following string Cryocon Model 32 Rev lt fimware rev code gt lt hardware rev code gt Where lt fimware rev code gt is the revision level of the unit s firmware and lt hardware rev code gt is the hardware revision code Query Syntax IDN Query Response lt Instrument Identification String gt OPC Operation Complete The OPC command will cause 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 Command Syntax OPC Query Syntax OPC Query Response 1 RST Reset Reset the controller This will cause a hardware reset in the Model 32 The

Model 32 / 32B User`s Manual - Cryogenic Control Systems, Inc.

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