Model 42/44 Cryogenic Temperature Controllers
Contents
1. _ zi s I a o d af f za i e a a I Aa oe Ei x 2 A a z T 2 os M Innovative Solutions in i Cryogenic Instrumentation me ri r x y Cryogenic Temperature Controller applications Maximum flexibility Two or four multipurpose input channels support Diode Platinum RTD and virtually all cryogenic NTC resistive temperature sensors Operation from lt 100mK to over 1020K with appropriate sensor Constant Voltage AC excitation extends the useful temperature range of resistive sensors Unique synchronous filter improves control accuracy and stability in cryocooler based systems E a Fe 5 14 Lia A mi Model 42 44 The Model 42 44 cryogenic temperature controllers are the first instruments in their class to extend operation to ultra low temperature providing robust support for He3 refrigerators at a very cost effective price The Model 42 has two multi purpose inputs and the Model 44 has four Each input is capable of temperature measurement to below 100mK by using a sophisticated 100V ratiometric resistance bridge For general purpose thermometry applications the inputs support a wide variety of standard sensors The dual output control loop circuits features power levels as high as 50W and as low as 50mW full scale in order to support ultra low temperature operation Cryo2. curves with up to 200 entries each Interpolation is performed using a Cubic Spline CalGen Calibration curve generator fits any Diode or resistor sensor curve at 1 2 or 3 user specified temperature points Control Outputs Number of Independent Control Loops Two Control Input Any sensor input Loop Update Rate 15Hz per loop Isolation Control loop circuitry is electrically isolated from all other internal circuitry Control Type PID table Enhanced PID Ramp or Manual Autotune Minimum bandwidth PID loop design PID Tables Six user PID tables available for storage of setpoint and heater range vs PID and heater range 16 entries table Set point 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 Contact Information Cryogenic Control Systems Inc PO Box 7012 Rancho Santa Fe CA 92067 Tel 858 756 3900 Fax 858 759 3515 E mail sales cryocon com Web www cryocon com Loop 1 Primary Heater Output Type 50 Watt short circuit protected linear current source Maximum compliance is selectable at 25V or 50V Ranges Four output ranges of 1 0A 333mA 100mA and 33mA full scale which correspond to 50W 5 0W 0 5W and 50mW when used with a 50Q load Load Resistan
3. standard PID type regulation will be performed Cryostat Protection Damage to a cryostat or critical sample is a serious problem with any cryogenic system The Model 42 44 implements the most robust set of protection features in the industry The Over Temperature Disconnect feature will disable the heater if an over temperature condition exists on any selected input channel A fail safe mechanical relay is used to disconnect the controller s heater thereby ensuring that the user s equipment is always protected The Maximum Setpoint feature is used to prevent the user from inadvertently entering a higher setpoint than the equipment can tolerate Setting the Maximum Power Limit will ensure that the controller can never output a heater power above the set limit Alarms The Model 42 44 supports visual remote and audible alarms Each may be independently programmed to assert or clear based on a high or low temperature condition or a detected sensor fault Latched alarms are asserted on an alarm condition and will remain asserted until cleared by the user Lowest Noise The Model 42 44 was designed for use in extremely low noise environments that cryogenic systems often require Linear mode power supplies are used throughout and sensor excitation current sources are not multiplexed Modern components and proven noise management techniques were carefully applied to every sensor excitation and heater output circuit in order to minimi
4. 0 standard curves for 100 1 000 or 10KQ devices This curve is used for temperatures from 70K to 1020K and is extended down to 30K for cryogenic use Operation to about 14K is possible with user Supplied curves The Model 42 44 provides robust support for the Negative Temperature Coefficient NTC sensors commonly used by cryogenic applications They include Ruthenium oxide Carbon Glass Cernox Carbon Ceramic Germanium and several others Since these sensors have a negative temperature coefficient the use of a constant voltage measurement method will reduce rather than increase power dissipation in the sensor as temperature decreases By maintaining the lowest possible power level sensor self heating is minimized and useful temperature range is greatly increased An additional advantage to constant voltage excitation is that NTC resistors lose sensitivity in the upper part of their range By auto ranging excitation current to maintain a constant voltage sensitivity and noise immunity in that range is greatly improved Sensor excitation used with all resistor sensors is a 3 25Hz bipolar square wave This effectively cancels thermal EMF induced offset errors that sometimes occur in cryogenic NTC Sensor Resistance Ranges systems Voltage Min Max Bias Resistance Resistance 100mV 1 0MQ 10 0mV 1 0MO The excitation source in the Model 42 44 is continuously 1 0mV 333KQ variable so there 100uV 33KQ are no s
5. 40VAC with detachable universal Euro line cord Specifications User Interface Display Type 20 x 2 character VFD 9mm character height Number of Inputs Displayed One to Four Keypad Sealed Silicon Rubber Temperature Display Six significant digits auto ranged 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 Model 42 or four Model 44 input channels each of which may be independently configured for any of the supported sensor types Sensor Connection 4 wire differential DIN 6 Connector Sensor Types See Supported Sensor Table Sensor Selection Front Panel or remote interface There are no internal jumpers or switches Input Configurations See input specifications table Bridge Modes Passive Constant Current Constant Voltage Bridge type Ratiometric resistance 2 bridge Differential excitation DC coupled AC Excitation Frequency All resistor sensors 3 25Hz bipolar square wave Sample Rate 15Hz per channel Digital Resolution 24 bits Measurement Accuracy See input specifications table Measurement Drift 15ppm C 25ppm C in the Meg ohm resistance range Isolation Input channel circuits are electrically isolated from all other internal circuitry Measurement Filter 0 5 1 2 4 8 16 32 and 64 Seconds Calibration Curves Built in curves for industry standard sensors plus six user
6. I An Applications Program Interface API package is supplied that facilitates communication with the instrument using the TCP IP interface It is supplied as a Microsoft Windows DLL that is easily linked with C C or Basic programs Rear Panel Connections Crragenia Gani systems ing O Modal 44 Tarmperolurea Controller TEKR 240 AC SD SO0Hr 175W box Made In Wa IEEE 485 2 Q AS 2 LAN c elnput Connectors DIN 6 recepticals provide 4 wire measurement connection plus shield eLoop 1 Heater output DIN 3 receptacle eLoop 2 Heater output DIN 3 receptacle eEthernet RJ 45 with LAN activity indicator LEDs elEEE 488 Standard IEEE 488 2 GPIB connector eRS 232 Null modem connector DB 9 pins eAC Power RFI filtered Power Entry Module including fuse drawer and line voltage selector Ordering Information Product Description S Model 42 Controller with two multi function sensor input channels and two control loops Model 44 Controller with four multi function sensor input channels and two control loops Controllers include User s Manual Cryo con software CD Two or Four input connectors two heater connectors a detachable line cord and a certificate of calibration Options Description o Configured for 90 100VAC with detachable USA power cord Configured for 110 120VAC with detachable USA power cord Configured for 220VAC with detachable universal Euro line cord Configured for 2
7. ce Selectable at 25Q or 50Q Minimum Load 10Q in 25W setting 40Q in 50W setting Resolution 1 0ppm of full scale power 20 bits Readbacks Heater output power Heatsink temperature Loop 2 Heater Output Type 10 Watt short circuit protected linear current source Maximum compliance is 25V Ranges Two output ranges of 450mA and 140mA full scale which correspond to 10W and 1 0W into a 50Q load Load Resistance 50Q for 10 Watt output Minimum Load 10Q Resolution 1 0ppm of full scale power 20 bits Readbacks Heater output power Heatsink temperature Status Outputs Audible and Visual Alarms Independent audible remote 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 Ethernet Connects to any Ethernet type Local Area Network Electrically isolated TCP IP user data socket provides remote control by using an ASCII command language HTTP provides built in web server for configuration via any web browser SMTP sends e mail based on alarm conditions RS 232 Serial port is an RS 232 standard null modem Data rates are 9600 19 200 38 400 and 57 200 Baud IEEE 488 GPIB Full IEEE 488 2 compliant Remote Programming Language IEEE 488 2 SCPI compliant LabVIEW drivers available for all interfaces User Setups Four User Setups are available that save and restore the complet
8. con s Model 42 44 are the first temperature controllers to incorporate Ethernet connectivity which adds a new dimension of flexibility to industrial and laboratory Major highlights of the Model 42 44 Dual loop control Loop 1 50 Watt four range Loop 2 10 Watt two range Fail safe cryostat protection features protect user equipment from damage Ethernet interface implements a remote command language in addition to an embedded web server and e mail Remote interfaces include Ethernet RS 232 and IEEE 488 2 GPIB LabView drivers available fad it AAV SE Input Flexibility The Model 42 has two sensor inputs whereas the Model 44 has four Each input can be easily configured to support virtually any type of cryogenic thermometer Configuration is performed from the instrument s front panel or a remote interface Silicon Diode sensors from Cryo con or any other manufacturer are directly supported over their full 1 4 to 500K range using built in calibration curves and sensor data Plus non volatile Flash memory is available for several custom or calibrated sensors A unique feature of the Model 42 44 is the use of a ratiometric AC resistance bridge technique to measure Positive Temperature Coefficient PTC resistor sensors including Platinum and Rhodium tlron RTDs This significantly reduces low frequency noise and drift to provide rock solid measurements Platinum RTD sensors use a built in DIN 43760 IEC 75
9. e configuration of the instrument General Ambient Temperature 25 C 5 C for specified accuracy Mechanical 8 5 W x 3 5 H x 12 D One half width 2U rack Instrument bail standard rack mount kit optional Weight 9 Lbs Power Requirement 100 120 220 or 240VAC 5 10 50 or 60Hz 150VA Conformity European CE certified Calibration NIST tracable 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 Cryogenic Control Systems Inc 2008 M42c0208 Specifications subject to change without notice
10. ignificant steps in sensor self heating Model 42 44 Supported Sensors ange Cryo con S900 S800 Diode 1 4 500K SI 440 430 410 Lakeshore DT 670 470 Cryo con CP 100 i Cryo con GP 100 Platinum RTD 14 1200K Cryo con XP 100 Cryo con XP 1K Rhodium lron 1 4 800K Oxford PHZ 0002 lt 100mK Germanium 100K Lakeshore GR 200A Carbon Glass 1 4 325K Lakeshore CGR 1 500 100mK 325K Lakeshore all types 100mK 300K TMi A1 Ruthenium Cryo con R400 Measurement accuracy is obtained by using 24 bit analog to digital conversion at a minimum sample rate of 15Hz per channel and is further enhanced by extensive use of Digital Signal Processing DSP Conversion of a sensor measurement into temperature is performed by using a Cubic Spline interpolation algorithm In addition to providing higher accuracy than conventional linear interpolation the Spline function eliminates discontinuities during temperature ramps or sweeps by ensuring that the first and second derivatives are continuous Input Specifications Diode sensors PTC resistor sensors NTC resistor sensors Excitation Mode DC Constant Current Passive AC Resistance Bridge Constant Voltage AC Resistance Bridge Ranges 2 25V 3909 3 9KQ 39KQ 1 0KQ 10KQ 100KQ 1 0MegQ Auto or range hold Accuracy 0 0 of Rdg of Range 0 005 0 0003 0 01 0 0005 4 to 30K 0 05 0 05 0 04 to 1M 0 15 0 15 Resol
11. into a 50Q load Loop 1 and Loop 2 heaters are completely independent and either heater can be controlled by any sensor input Control modes are Manual PID Ramp and PID Table The industry standard Proportional Integral Derivative or PID control loop is implemented as a DSP algorithm and is enhanced to minimize set point overshoot and differentiator noise The direction of the control loop can be easily reversed to accommodate thermoelectric type coolers where power is applied to cool rather than heat The field proven Autotune function of the Model 42 44 involves the use of a specific output waveform to first develop a process model then generate the optimum P and D coefficients Cryogenic systems often require stable control over a wide range of temperatures Here control loop tuning parameters can be significantly different at different temperatures For this reason the Model 42 44 offers PID tables that store optimum tuning parameters and heater range vs setpoint temperature Six PID tables are available Each contains PID and heater range settings for up to 16 temperature setpoints The Model 42 44 will perform a temperature ramp function using a specified maximum 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 Upon reaching the new setpoint ramp mode will be terminated and
12. lows stable precise cost effective measurements in laboratory or industrial environments as well as in remote distributed data acquisition systems Using the Ethernet HTTP protocol the instrument s embedded web server allows the instrument to be viewed and configured from any web browser Using the Ethernet SMTP protocol the controller will send e mail based on selected alarm conditions E mail is configured by using the web page interface The TCP IP data port server brings fast Ethernet connectivity to all common data acquisition software programs including LabView TCP IP protocol is used to implement an ASCII text based command language like those commonly used with IEEE 488 or RS 232 interfaces This is the primary way that user software interfaces to the instrument The remote command language is SCPI compliant according to the IEEE 488 2 specification With Ethernet connectivity the user has complete control of the instrument by using any web enabled device from desktop PC to a wireless Pocket PC It is platform and operating system independent working equally well with Windows Linux or Macintosh based computers There are no expensive cards or cables and best of all no confusing configuration requirements Utility Software Utility software is provided that connects any Windows based personal computer to the Model 42 44 via either of its remote interfaces This software provides a graphical control panel tha
13. t greatly simplifies instrument setup and configuration Features include e Continuous strip chart monitoring of all inputs and outputs e Downloading uploading viewing and editing of sensor calibration curves Most file formats are directly supported and can be easily converted to Cryo con s standard format e Downloading or uploading PID temperature zone tables e A Terminal mode to communicate with the controller e Full instrument calibration capability E Cryo Con Model 14 Temperature Monitor Microsoft Internet Explorer File Edit View Favorites Tools Help ay Ry Back GQ x a TN JO search 5 Favorites O do Sa Address g Cad1 backupquyi UsersManuals M42 TMPabmk1le7kyj htm Innovative Solutions in Cryogenic Instrumentation er sis e p Cryo con Model 44 Cryogenic Temperature Controller Temperature Cold Plate 0 153K Second Stage 1 403K Sorb Pump 55 632K Rad Shield 127 556K High Alarm Control Loops Loop 1 Source ChA Status 4 326mW Loop 2 Source Chc Status 0 853W Date 02 15 07 Time 13 45 Cryocon Model 42 203946 1 04 MAC Address 00 06 3C 1B8 00 3D E ee a te Local intranet WY LabView LabView drivers are supplied for the Ethernet TCP IP IEEE 488 and RS 232 interfaces Conversion of LabView programs from IEEE 488 or RS 232 to Ethernet TCP IP is as easy as changing the interface setting in the open VI Ethernet AP
14. ution of Range 0 00004 0 0003 0 0003 Excitation Current 10uA DC 1 0mA 100A 10uA Max 2 5mA to 2 0nA continuous auto ranged Sensor Curves The Model 42 44 includes built in curves that support most industry standard temperature sensors Additionally six user calibration curves are available for custom or calibrated sensors Each user curve may have up to 200 entries and may be entered from the front panel or transferred via any of the available remote interfaces New calibration curves may be generated using the CalGen feature to fit any existing Diode Platinum or NTC resistor calibration curve at up to three user specified temperature points This provides an easy and effective method for obtaining higher accuracy temperature measurements without expensive sensor calibrations The Model 42 44 continuously tracks temperature history independently on each input channel and provides a Statistical summary that indicates the channel s minimum maximum average and standard deviation Also shown are the slope and the offset of the best fit straight line of temperature history data Dual Control Loops The Loop 1 heater output is a linear low noise RFI filtered current source that can provide up to 1 0 Ampere into 50Q or 250 resistive loads Four full scale ranges are available in decade increments down to 50mW The Loop 2 heater output has two output ranges of 10 Watts and 1 0 Waitt full scale
15. ze conducted noise Electrical isolation is used to prevent noise pickup by sensitive analog circuits and to eliminate ground loops The enclosure of the Model 42 44 is all Aluminum with wide conductive overlaps on all mating metal surfaces so that radiated RFI noise is virtually eliminated An effective shielding and grounding scheme further allows the user to minimize both conducted and radiated noise Easy to Use The Model 42 44 s user interface consists of a large bright Vacuum Fluorescent display and a full 20 key keypad All features and functions of the instrument can be accessed via this simple and intuitive menu driven interface Accessing primary instrument functions such as display units and heater setpoint require only a single key press More complex features can be accessed by scrolling through short menus Temperature displays are autoranged to show the most number of significant digits Built in filters can be used to smooth temperature data and display resolution can be selected for optimum viewing Units of K C F Volts or Ohms may be selected Power switch is on the front panel for easy access Remote Control Standard Remote Interfaces include Ethernet RS 232 and IEEE 488 GPIB All interfaces are electrically isolated to prevent ground loops The Model 42 44 connects directly to any Ethernet Local Area Network LAN to make measurements easily and economically Connection to any existing LAN al
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