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350 Manual - Lake Shore Cryotronics, Inc.

1. Lake Shore Cryotronics Instrument Service Department Mailing address 575 McCorkle Blvd Westerville Ohio USA 43082 8888 h sales lakeshore com Sales E mail mall address service lakeshore com Instrument Service Telephone 614 891 2244 Sales P 614 891 2243 select the option for service Instrument Service Fax 614 818 1600 Sales s 614 818 1609 Instrument Service Online request for service http www lakesh ore com service Pages Instrument Service Request For Service aspx TABLE 8 10 Contact information Model 350 Temperature Controller 8 14 2 Return of Equipment 8 14 3 RMA Valid Period 8 14 4 Shipping Charges 8 14 5 Restocking Fee 8 14 2 ReturnofEquipment 177 The temperature controller is packaged to protect it during shipment The user should retain any shipping carton s in which equipment is originally received in the event that any equipment needs to be returned If the original packaging is not available a minimum of 76 2 mm 3 in of shock adsorbent packing material should be placed snugly on all sides ofthe instrument in a sturdy corrugated cardboard box Please use reasonable care when removing the temperature controller from its protective packaging and inspect it carefully for damage If itshows any sign of damage please file a claim with the carrier immediately Do not destroy the shipping container it will be required by the carrier as evidence to support claims Call Lake Shore for return a
2. Ramp Rate Control Input 0 1 100 K min Default A LIB OC OD Upper boundary K Ramp Rate Control Input 0 1 100 K min Default Upper boundary Ramp Rate Control Input 0 1 100 K min Default A OB OC OD Upper boundary K Ramp Rate Control Input 0 1 100 K min Default gt UJ o oS A gt w O z A gt ow O S ZA iv o o A Upper boundary Ramp Rate 0 1 100 K min Control Input fault De Upper boundary Ramp Rate 0 1 100 K min Control Input fault De Upper boundary Ramp Rate 0 1 100 K min Control Input fault De Upper boundary Ramp Rate 0 1 100 K min Control Input fault De A B C ID OK 5 4 Bipolar Control 5 5 Warm Up Supply 5 5 1 Warm Up Percentage 5 4 BipolarControl 89 The most common type of temperature control output device is a resistive heater which requires only unipolar output since they will add heat regardless of the polar ity of the excitation voltage There are however temperature control devices that are bipolar These devices such as thermoelectric devices can work in both polarities moving heat from one side of the device to the other when a current is applied T
3. To event summary Standardevent 7 6 5 4 3 2 1 0 Bi bit ESB of status Ao o lus er sre e 4 212 ecimal e Riera row usea cme ee usea ave usea oF FIGURE 6 2 Standard event status register Name 6 2 5 2 Operation Event Register Set The Operation Event Register reports the interface related instrument events listed below Any or all of these events may be reported in the operation event summary bit through the enable register FIGURE 6 3 The Operation Event Enable command OPSTE programs the enable register and the query command OPSTE reads it OPSTR reads and clears the Operation Event Register OPST reads the Operation Condition register The used bits of the Operation Event Register are described as fol lows m Processor Communication Error COM Bit 7 this bit is set when the main pro cessor cannot communicate with the sensor input processor m Calibration Error CAL Bit 6 this bitis set if the instrument is not calibrated or the calibration data has been corrupted m Autotune Done ATUNE Bit 5 this bitis set when the Autotuning algorithm is NOT active m New Sensor Reading NRDG Bit 4 this bitis set when there is a new sensor reading m Loop 1 Ramp Done RAMP1 Bit 3 this bit is set when a loop 1 setpoint ramp is completed m Loop 2 Ramp Done RAMP2 Bit 2 this bit is set when a loop 2 setpoint ramp is completed m Sensor Overload OVLD Bit 1 this bit is set
4. 00 cece cece rasin me 4 1 4 5 Use Additional Input Types with Option Cards 0 cece cece eee e eens 4 SEMSOPSEICCE OM s oscar ore EEE AEAEE ATE EAEE EAEE 4 Model 350 Specifications cc cece ccc eee eene 7 1 6 1 Input Specifications 6 cece eee cece ee e meme 7 1 6 2 Sensor Input Configuration essersi so ccc c cece cece eee e e 8 1 6 3 Th ntriOImetty c cu ius vedic en esr rro anaE AANE EENE AEREA EER EA 8 Ne SEG dro MEAE 9 1 6 4 1 Heater Outputs Outputs 1 and 2 0c ee ees 9 1 6 4 2 Analog Outputs Outputs 3 and 4 ccc ee ees 10 16 5 Front Panel serene er ee pure pati ise dada cba d TER E MUR 10 1 6 6 lin bela Oe ces rds erunt ten bae A aA Nia a T TEE d EE 11 1 6 7 Gell kalzcebracetei tust MR RN 11 Safety Summary and Symbols siserernrerer priini tent tirna ESNA EONA EAAS Na ened 12 GENEL m E 15 Useful Temperature Range ccc cece cece eee e e eem 15 Cryogenic Cooling System Terminology csssssss e 15 2 3 1 Dilution Refrigerator Terminology essy sissessrdexaecarranirar inrter erkin 15 23 2 JHE COSTAE iocus e irr xe EEN ENE PESAR EEE M RIDE E RE EE 17 Model 350 Theory of Operation 00 0 e cece eee een n 18 2 4 1 Sensor Resistance Measurement sssssssssssssssssse n 18 2 4 2 Excitation Modes isssssssssssssssssssssssseee esee eee eee ena 19 2 4 2 1 Autorange Excitation Mode issssssssssss 19 2 4 2 2 Manual Excitation Mode s
5. 2 11 1 4 Outputs 3 and 4 Outputs 3 and 4 are analog voltage outputs that can be used for various purposes including closed loop PID control and still heater applications For more information on these outputs refer to section 3 6 For best temperature measurement accuracy position the heater so that tempera ture gradients across the sample is minimized For best control the heater should be in close thermal contact with the cooling power Geometry ofthe load can make one or both of these difficult to achieve That is why there are several heater shapes and sizes Resistive wire like nichrome is the most flexible type of heater available The wire can be purchased with electrical insulation and has a predictable resistance per given length This type of heater wire can be wrapped around a load to give balanced even heating ofthe area Similarto sensor lead wire the entire length ofthe heater wire should be in good thermal contact with the load to allow for thermal transfer Ther mal anchoring also protects the wire from over heating and burning out Resistive heater wire is also wound into cartridge heaters Cartridge heaters are more convenient but are bulky and more difficult to place on small loads A typical car tridge is 6 35 mm 0 25 in in diameter and 25 4 mm 1 in long The cartridge should be snugly held in a hole in the load or clamped to a flat surface Thermal anchoring for good thermal contact is again important La
6. 4 5 2 1 Warm Up Supply Warm Up Supply mode is designed for controlling an external power supply used for rapidly increasing the temperature in the controlled system for example to bring a system to room temperature in order to change samples Refer to section 5 5 for more information on warm up supply operation Refer to section 3 6 5 for the procedure to install an external power supply for warm up supply mode 4 5 2 2 Monitor Out Refer to section 5 6 for more information on Monitor Out mode The Model 350 hasthree computer interfaces IEEE 488 USB and Ethernet Only one ofthese interfaces can be active at one time Use the Interface menu to configure which interface is active and to configure the parameters related to the selected interface Menu Navigation Interface Enabled USB Ethernet IEEE 488 Default USB Lake Shore www lakeshore com CRYOTRONICS 84 CHAPTER 4 Operation 4 6 1 USB 4 6 2 Ethernet 4 6 3 IEEE 488 4 7 Locking and Unlocking the Keypad Model 350 Temperature Controller The USB interface is provided as a convenient way to connect to most modern com puters as a USB interface is provided on nearly all new PCs as of the writing of this manual The Model 350 USB driver which must be installed before using the inter face section 6 3 3 creates a virtual serial com port which can be used in the same way as a traditional serial com port Refer to Chapter 6 for details on computer inter fac
7. 6 3 3 Installing the USB Driver Model 350 Temperature Controller The Model 350 USB interface provides a convenient way to connect to most modern computers as a USB interface is provided on nearly all new PCs as of the writing of this manual The USB interface is implemented as a virtual serial com port connec tion This implementation provides a simple migration path for modifying existing RS 232 based remote interface software It also provides a simpler means of commu nicating than a standard USB implementation The Model 350 has a B type USB connector on the rear panel This is the standard connector used on USB peripheral devices and it allows the common USB A type to B type cable to be used to connect the Model 350 toa host PC The pin assignments for A type and B type connectors are shown in section 8 10 The maximum length of a USB cable as defined by the USB 2 0 standard is 5 m 16 4 ft This length can be extended using USB hubs every 5 m 16 4 ft up to five times for a maximum total length of 30 m 98 4 ft The USB interface emulates an RS 232 serial port at a fixed 57 600 baud rate but with the physical connections of a USB This programming interface requires a cer tain configuration to communicate properly with the Model 350 The proper configu ration parameters are listed in TABLE 6 5 Baud rate 57 600 Data bits 7 Start bits 1 Stop bits 1 Parity Odd Flow control None Handshaking None
8. Proportional Integral Derivative MHP Output 0 1 1000 0 11000 0 200 0 100 Proportional Integral Derivative MHP Output 0 1 1000 0 1 1000 0 200 0 100 Proportional Integral Derivative MHP Output 0 1 1000 0 1 1000 0 200 0 100 Proportional Integral Derivative MHP Output 0 1 1000 0 1 1000 0 200 0 100 Proportional Integral Derivative MHP Output 0 11000 0 1 1000 0 200 0 100 Proportional Integral Derivative MHP Output 0 1 1000 0 1 1000 0 200 0 100 Model 350 Temperature Controller Heater Range 1 Off Med Low High Heater Range 1Off Med Low High Heater Range 1Off Med Low High Heater Range 1Off Med Low High Heater Range 1Off Med Low High Heater Range 1Off Med Low High Heater Range 1Off Med Low High Heater Range 1Off Med Low High Heater Range 1Off Med Low High Heater Range 1Off Med Low High FIGURE 5 1 Record of Zone settings Menu Navigation Zones Output 1 or 2 zones 1 to 10 Interface Command ZONE UJ o oS ZA w O oS Aw gt w O oS A Upper boundary Ramp Rate 0 1 100 K min Control Input fault De Upper boundary Ramp Rate 0 1 100 K min Control Input fault De Upper boundary
9. TABLE 6 5 Host com port configuration The USB hardware connection uses the full speed 12 000 000 bits sec profile of the USB 2 0 standard however since the interface uses a virtual serial com port at a fixed data rate the data throughput is still limited to a baud rate of 57 600 bits s The Model 350 USB driver has been made available through Windows Update This is the recommended method for installing the driver as it will ensure that you always have the latest version of the driver installed If you are unable to install the driver from Windows Update refer to section 6 3 3 3 to install the driver from the web or from the disc provided with the Model 350 These procedures assume that you are logged into a user account that has adminis trator privileges 6 3 3 1 Installing the Driver From Windows Update in Windows 7 and Vista 1 Connectthe USB cable from the Model 350 to the computer 2 Turn on the Model 350 3 Whenthe Found New Hardware wizard appears select Locate and install driver software recommended 4 If User Account Control UAC is enabled a UAC dialog box may appear asking if you want to continue Click Continue 5 The Found New Hardware wizard should automatically connect to Windows Update and install the drivers 6 3 3 Installingthe USB Driver 117 If the Found New Hardware wizard is unable to connect to Windows Update or find the drivers a message to Insert the disc that came with your Lake Shor
10. Alpha Numeric Entry and Setting Selection Referto the respective entry mode descriptions below During menu navigation press Escape Exit Menu to per form the Exit Menu function this will not cancel any setting changes m Number Entry allows you to enter number data using the number pad keys Num ber pad keys include the numbers 0 9 and the decimal point The propor tional control parameter is an example of a parameter that requires number entry During a number entry sequence use the number entry keys to enter the number value press Enterto accept the new data Press Escape once to clearthe entry and twice to return to the Menu Navigation mode m Alpha Numeric Entry allows you to enter character data using the number pad keys and the A and W keys The input sensor name is an example of a parameter that requires Alpha Numeric Entry Press A or Wto cycle through the upper and lower case English alphabet numerals O through 9 and a small selection of com mon symbols Press Enter toadvance the cursorto the next position orto save the string and return from Alpha Numeric Entry mode if in the last position Press Escape to move the cursor back one position or tocancel all changes and return from Alpha Numeric Entry mode if at the first position Press any ofthe number pad keys except for to enter that character into the string and advance the cursor to the next position automatically or to save the string and return to Menu
11. Embedded Curve Handler utility d Lake Shore Embedded Curve Handler Utity meram x RE Genicot Weine White Toisen zDeeisrromdnsiument Cue ame PT 1000 HU LakeShore Curve Handler A 2 a Duis Fe vin STANDARD 3000 1 sos pso 2m E pe2 30 0 2500 je o 2 280 2000 7 nm fzo d 1700 ohms 1 500 ogag eee par wo 200 300 aw so 600 700 800 is usn 515 0 E mus sso E Kelvin FIGURE 6 9 Screen shot of the Curve Handler The Ethernet Firmware Updater utility provides a means of updating the firmware that controls the Ethernet functionality of the Model 350 It also updates the embed ded website and the Java utilities found on the Utilities web page Please visit www lakeshore com for the latest firmware updates Zi lake Shore Ethernet Firmware Updater Unity LET Uploading firmware fles EthernetFirmwareUpdater jar FIGURE 6 10 Screenshot of the Ethernet Firmware Updater This utility only updates the Ethernet firmware and notthe instrument firmware Another utility is provided at the Lake Shore website www lakeshore com for updating the instrument firmware To use the Ethernet Firmware Updater utility first ensure that your Java Runtime Environment is at version 1 6 0 or higher and then use this procedure to download the Ethernet firmware Updater utility 1 Download the latest Model 350 Ethernet Firmware file from
12. FILTER B 1 10 2 term filter input B data through 10 readings with 2 of full scale window Input Filter Parameter Query FILTER input term a input Specifies input to query A D D1 D5 for 3062 option off on gt lt points gt lt window gt term n nn nn refer to command for description Heater Output Query HTR output term n output Heater output to query 1 Output 1 2 Output 2 heater value term nnn n lt heater value gt Heater output in percent HTR is for the Heater Outputs 1 and 2 only Use AOUT for Outputs 3 and 4 Lake Shore www lakeshore com CRYOTRONICS 146 HTRSET Input Format Example HTRSET Input Format Returned Format HTRST Input Format Returned Format Remarks IEEE Input Format Example IEEE Input Returned Format Model 350 Temperature Controller CHAPTER 6 Computer Interface Operation Heater Setup Command HTRSET output heater resistance max current max user current gt lt current power gt term n n n n nnn n lt output gt lt htr resistance gt Specifies which heater output to configure 1 or 2 Heater Resistance Setting output 1 only 1 25 0 2 500 Specifies the maximum heater output current output 1 only O User Specified 1 0 707A 2 1A 3 1 141A 4 2A Specifies the maximum heater output current if max current is set to User Specified output 1 only Specifies whet
13. Interface Enabled Ethernet There are several parameters for configuring the Model 350 Ethernet interface and three methods for configuring these parameters This section contains a brief expla nation of each of these A comprehensive discussion of computer networking is beyond the scope ofthis manual These settings may depend on your network config uration contact your network administrator for assistance 6 4 1 1 Network Address Parameters Network address parameters include the IP address the subnet mask and the gate way address The network address parameters of the Model 350 can be configured using one of three methods DHCP Auto IP or Static IP See section 6 4 1 2 for details on each ofthese configuration methods m IPAddress an IP address is required for a device to communicate using TCP IP which is the protocol generally used for Ethernet devices and the Model 350 The IP version used by the Model 350 is IPv4 The IPv6 standard is not supported All references to the IP protocol from this point forward will be referring to IPv4 An IP address is a 32 bit logical address used to differentiate devices on a net work It is most often given in dotted decimal notation such as nnn nnn nnn nnn where nnn is a decimal number from 0 to 255 m Subnet Mask a sub network or subnet is a group of devices within a network that have a common designated IP address routing prefix A subnet mask is a 32 bit bit mask that signifies whic
14. NRDG RAMP1 RAMP2 OVLD ALARM Name COM Processor communication error CAL Calibration error ATUNE Autotune process completed NRDG New sensor reading RAMP1 Loop 1 ramp done RAMP2 Loop 2 ramp done OVLD Sensor overload ALARM Sensor alarming FIGURE 6 1 Model 350 status system Lake Shore www lakeshore com CRYOTRONICS 110 CHAPTER 6 Computer Interface Operation Model 350 Temperature Controller 6 2 4 4 Status Byte Register The Status Byte register typically referred to as the Status Byte is a non latching read only register that contains all ofthe summary bits from the register sets The status ofthe summary bits are controlled from the register sets as explained in sec tion 6 2 4 1 to section 6 2 4 3 The Status Byte also contains the Request for Service RQS Master Summary Status MSS bit This bitis used to control the Service Request hardware line on the bus and to report if any ofthe summary bits are set via the STB command The status ofthe RQS MSS bit is controlled by the summary bits and the Service Request Enable Register 6 2 4 5 Service Request Enable Register The Service Request Enable Register determines which summary bits in the Status Byte will set the RQS MSS bit of the Status Byte You may write to or read from the Ser vice Request Enable Register Each Status Byte summary bit is logically ANDed to the corresponding enable bit of the Service Request Enable Register When you
15. 2 7 Operating Trade OFS scusines te eee ee re Rn Ren EEEREN tee RR CEA URS 24 2 7 1 Sensor Self Heating versus Excitation ssssssssssssssssssssesssseees 24 2 7 2 Excitation vs Signal to Noise ssssssssssssssssssssseee eene 24 2 7 3 Considerations When Measuring Ultra Low Temperatures Below 300 mK 25 2 8 Temperature Sensor Selection 5 5 eese desse e con e nex EL TUR ERRARE eens 28 28 Teimperat re Range pror e ei v pet Yt RE Secdm FRE CUR PIS 28 2 8 2 Sensor SernsItlVIty serseri hetero e RR DUE ERRRdberp xe EE OUR RE UNE 28 2 8 3 Environmental Conditions csse eene 28 2 8 4 MeasurementACcculacy coe re I ye a EA rr Ra re b x en 28 28 5 Sensor Package ee eter ina A ESADE EAREN TRA Ya Fed eed 29 2 9 Sensor CaliDrations separen ecce exert EE RARI RE UE PERUTREARIEEPNEMP RP geen 29 2 9 1 Precision Calibration emen 29 AACHEN 30 2 9 3 Sensors Using Standard CUIVES 0 00 c cece eee cece cece ee ee eee 30 29 4 Curve Handler M iis once outer eee ee tor Eod bcp d agace PIE EE denen 30 2 10 Sensor installation wis coiere E ber IER ERO RIS IG eR PR uq ecEEISE 30 2 10 1 Mounting Materials csse m 31 2 10 2 SensorLocatloh io ier a RE ERE EY ERR ex sada A RIA 31 2 10 3 Thermal Conductivity 00 cece cece eect nee eee en ee eee e enna 31 2 10 44 ColitaCL ATedi cist onercisaciacee mu seaiadeteesecseanneis RUE EN IWOR ERE AR 31 2 10 5 Contact PreSSUTe use ees et uses deat a OUR RE EM RN E Ren eb SEO
16. 3 Input D 4 Custom 5 Four Loop 6 All Inputs 7 Input D2 8 Input D3 9 Input D4 10 Input D5 for 3062 option lt num fields gt When mode is set to Custom specifies number of fields display locations to display O 2 large 1 4 large 2 8 small When mode is set to All Inputs specifies size of readings O small with input names 1 large without input names displayed output Specifies which output and associated loop information to display in the bottom half ofthe custom display screen 1 Output 1 2 Output 2 3 Output 3 4 Output 4 DISPLAY 4 0 1 term set display mode to Custom with 2 large display fields and set custom output display source to Output 1 The num fields and displayed output commands are ignored in all display modes except for Custom Display Setup Query DISPLAY term lt mode gt lt num fields output source term n n n refer to command for description Input Filter Parameter Command FILTER input off on points window term a n nn nn input Specifies inputto configure A D D1 D5 for 3062 option off on Specifies whether the filter function is O Offor 1 On points Specifies how many data points the filtering function uses Valid range 2 to 64 lt window gt Specifies what percent of full scale reading limits the filtering function Reading changes greater than this percentage reset the filter Valid range 1to 10
17. 3 DIO 3 Data input output line 3 4 DIO4 Data input output line 4 5 EOI End or identify 6 DAV Data valid 7 NRFD Not ready for data 8 NDAC No data accepted 9 IFC Interface clear 10 SRQ Service request 11 ATN Attention 12 SHIELD Cable shield 13 DIO 5 Data input output line 5 14 DIO 6 Data input output line 6 15 DIO7 Data input output line 7 16 DIO8 Data input output line 8 17 REN Remote enable 18 GND6 Ground wire twisted pair with DAV 19 GND7 Ground wire twisted pair with NRFD 20 GND8 Ground wire twisted pair with NDAC 21 GND9 Ground wire twisted pair with IFC 22 GND 10 Ground wire twisted pair with SRQ 23 GND 11 Ground wire twisted pair with ATN 24 GND Logic ground TABLE8 7 IEEE 488 rear panel connector details Electrostatic Discharge ESD may damage electronic parts assemblies and equip ment ESD is a transfer of electrostatic charge between bodies at different electro static potentials caused by direct contact or induced by an electrostatic field The low energy source that most commonly destroys Electrostatic Discharge sensitive devices is the human body which generates and retains static electricity Simply walking across a carpet in low humidity may generate up to 35 000 V of static electricity Current technology trends toward greater complexity increased packaging density and thinner dielectrics between active elements which results in electronic devices with even more ESD sensitivity Some
18. 6 2 4 Status System Overview Model 350 Temperature Controller The Model 350 implements a status system compliant with the IEEE 488 2 standard The status system provides a method of recording and reporting instrument informa tion and istypically used to control the Service Request SRQ interrupt line A dia gram ofthe status system is shown in FIGURE 6 1 The status system is made up of status register sets the Status Byte register and the Service Request Enable register Each register set consists of three types of registers condition event and enable 6 2 4 1 Condition Registers Each register set except the Standard Event Register set includes a condition regis ter as shown in FIGURE 6 1 The condition register constantly monitors the instru ment status The data bits are real time and are not latched or buffered The register is read only 6 2 4 2 Event Registers Each register set includes an event register as shown in FIGURE 6 1 Bits in the event register correspond to various system events and latch when the event occurs When an event bit is set subsequent events corresponding to that bit are ignored Set bits remain latched until the register is cleared by a query command such as ESR ora CLS command The register is read only 6 2 4 3 Enable Registers Each register set includes an enable register as shown in FIGURE 6 1 An enable regis ter determines which bits in the corresponding event register will set the
19. CX 1050 HT 1 4K to 420 Ki T gt 2K amp BS19T Cernox CX 1070 HT 4 Kto 420 K1 T gt 2K amp B lt 19T Cernox CX 1080 HT 20 K to 420 K1 T gt 2K amp B lt 19T Germanium GR 300 AA 0 35 K to 100 K Not recommended Germanium GR 1400 AA 1 8 K to 100 K Not recommended Rox RX 102B 0 1 Kto 40 K T gt 2K amp B lt 10T Rox RX 103 1 4 Kto 40K T gt 2K amp B lt 10T Rox RX 202 0 5 K to 40 K T gt 2K amp B lt 10T ae 100 Q platinum PT 102 3 14Kto873K T 40K amp B 2 5T Ea eae aes 100 Q platinum PT 111 14K to 673K T gt 40K amp BS2 5T Rhodium iron RF 800 4 1 4K to 500 K T gt 77K amp BS8T Diodes Silicon Diode DT 670 SD 1 4K to 500 K T260K amp BS3T 3062 Silicon Diode DT 670E BR 30K to 500K T260K amp BS3T Silicon Diode DT 414 1 4K to 375K T260K amp BS3T Silicon Diode DT 421 1 4K to 325K T260K amp BS3T Silicon Diode DT 470 SD 1 4K to 500 K T260K amp BS3T Silicon Diode DT 471 SD 10 K to 500 K T260K amp BS3T GaAlAs Diode TG 120 P 1 4K to 325K T 4 2K amp BX5T GaAlAs Diode TG 120 PL 1 4 K to 325 K T gt 4 2K amp B lt 5T GaAlAs Diode TG 120 SD 1 4 K to 500 K T gt 4 2K amp B lt 5T Capacitance 3061 CS 501 1 4 K to 290 K T gt 4 2K amp B lt 18 7T Thermocouples Type K 9006 006 3 2 Kto 1505 K Not recommended 3060 Type E 9006 004 3 2 K to 934K Not recommended Chromel AuFe 0 07 9006 002 1 2 Kto 610 K Not recommended 1 Non HT version maximum temperature 325 K TABLE 1 1 Sensor temperature range sensors sold separately Lake Shore www lakeshore com CRYO
20. Gateway Gateway address for static configuration Pri DNS gt Primary DNS address for static configuration Sec DNS gt Secondary DNS address for static configuration Pref Host Preferred Hostname 15 character maximum Pref Domain Preferred Domain name 64 character maximum Description Instrument description 32 character maximum Network Settings Query NET term lt DHCP gt lt AUTO IP gt lt IP gt lt Sub Mask gt lt Gateway gt lt Pri DNS gt lt Sec DNS gt lt Pref Host gt lt Pref Domain gt lt Description gt term n n dd dd dd dd dd s 15 s 64 s 32 refer to command for description Network Configuration Query NETID term lan status gt lt IP gt lt sub mask gt lt gateway gt lt pri DNS gt lt sec DNS gt lt mac addr gt lt actual host name gt lt actual domain gt term n dd dd dd dd dd hh hh hh hh hh hh s 15 s 32 lt lan status gt Current status of Ethernet connection 0 Connected Using Static IP 1 Connected Using DHCP 2 Connected Using Auto IP 3 Address Not Acquired Error 4 Duplicate Initial IP Address Error 5 Duplicate Ongoing IP Address Error 6 Cable Unplugged 7 Module Error 8 Acquiring Address 9 Ethernet Disabled Refer to section 6 4 2 1 for details on lan status IP Configured IP address sub mask gt Configured subnet mask gateway Configured gateway address pri DNS gt Configured primary DNS address sec DNS gt Configured sec
21. However once data acquisition has begun the Start button becomes a Stop button and data acquisition can be terminated by pressing Stop but ton If you are not logging to a file data acquisition will continue until you press Stop 6 5 4 3 Chart Functionality By default the chart 6 will autoscale in both the x and y axis The time scale slider 7 is provided to adjustthe time scale window x axis scaling When less than one hour of data has been logged the slider will allow a time window between 1 and 60 min in increments of 1 min As the total elapsed time increases the values on the time scale slider will also increase to allow time windows proportional to the elapsed time A y axis is added foreach unique measurement unit ofthe selected readings Each y axis will be autoscaled so if more than one reading is being taken in the same unit the scale for the associated axis will be set such thatthe largest values of all readings are at the extremes Data that is charted on the same axis butthat is far apart in magnitude will result in low resolution for each data series Manual zooming ofthe chart can be achieved either by using the mouse wheel or by clicking and dragging a box around the area ofthe chart to zoom to Manual panning can be achieved by holding the Ctrl key then clicking and dragging the chart After manually zooming or panning autoscaling in both axes is turned off and Reset Zoom Pan becomes active To return to autos
22. Symbols Model 350 Temperature Controller Observe these general safety precautions during all phases of instrument operation service and repair Failure to comply with these precautions or with specific warn ings elsewhere in this manual violates safety standards of design manufacture and intended instrument use Lake Shore Cryotronics Inc assumes no liability for Cus tomer failure to comply with these requirements The Model 350 protects the operator and surrounding area from electric shock or burn mechanical hazards excessive temperature and spread offire from the instru ment Environmental conditions outside of the conditions below may pose a hazard to the operator and surrounding area m Indooruse Altitude to 2000 m Temperature for safe operation 5 9C 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 Overvoltage category II Pollution degree 2 IPXO not protected against harmful ingress of water Ground the Instrument To minimize shock hazard the instrument is equipped with a 3 conductor AC power cable Plug the power cable into an approved 3 contact electrical outlet or use a 3 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 a
23. The bottom half ofthe display contains information related to the control loop that is using the sensor input provided in the top half of the display as its Control Input parameter Only the items applicable to the control loop will be displayed Specifi cally the number ofthe control loop output followed by the Output Mode setting is displayed The P 1 D Manual Output Setpoint and Heater Output information ofthe control loop are also displayed If no control loop uses the sensor input then no infor mation is applicable The input display modes are unique in that they can be set temporarily by pressing the A B C or D front panel keys After the key is pressed the respective input display mode becomes active for approximately 10 s before returning to the configured dis play mode This provides quick access to each input and each associated control loop forgathering information or changing control loop parameters Press any active keys while the temporary display mode is active to reset the timeout period ofthe tempo rary display Press Escape or the same temporary display key again to manually return the display to the configured display mode Press and hold a temporary display key until an audible beep is heard about 3 s to cause the configured display mode to change to the input display mode associated with that key Menu Navigation Display Setup Display Mode nput A B C D Each input can also be accessed by pressing
24. The following sections describe the data points you need to supply and the expected accuracy ofthe resulting curves A feature similar to SoftCal is available for compensating thermocouples using the Curve Handler program Both DT 400 Series and platinum SoftCal algorithms require a standard curve that is already present in the Model 350 When you enterthe type of sensor being cali brated the correct standard curve must be selected When calibration is complete you must assign the new curve to an input The Model 350 does not automatically assign the newly generated curve to either input Calibration data points must be entered into the Model 350 These calibration points are normally measured at easily obtained temperatures like the boiling point of cryo gens Each algorithm operates with 1 2 or 3 calibration points The range of improved accuracy increases with more points There are two ways to get SoftCal calibration data points you can record the response of an unknown sensor at well controlled temperatures or you can purchase a SoftCal calibrated sensor from Lake Shore There are advantages to both methods m User when you can provide stable calibration temperatures with the sensor installed SoftCal calibration eliminates errors in the sensor measurement as well asthe sensor Thermal gradients instrument accuracy and other measure ment errors can be significant to some users Calibration can be no betterthan us
25. WEBLOG user pass sets the username to user and the password to pass Strings can be sent with or without quotation marks but to send a string that con tains spaces commas or semi colons quotation marks must be used to differentiate the actual parameter separator Website Login Parameter Query WEBLOG term username password term s 15 s 15 refer to command for description Note that all strings returned by the Model 350 will be padded with spaces to main tain a constant number of characters Lake Shore www lakeshore com CRYOTRONICS 158 CHAPTER 6 Computer Interface Operation ZONE Input Format Remarks Example ZONE Input Format Returned Format Model 350 Temperature Controller Control Loop Zone Table Parameter Command ZONE lt output gt lt zone gt lt upper bound gt lt P value gt lt I value lt D value gt lt mout value gt lt range gt lt input gt lt rate gt term n nn nnnnn nnnnn nnnnn nnnn nnnnn n n nnnn term lt output gt Specifies which heater output to configure 1 4 zone Specifies which zone in the table to configure Valid entries are 1 10 upper bound Specifies the upper Setpoint boundary ofthis zone in kelvin P value Specifies the P for this zone 0 1 to 1000 lt l value Specifies the I for this zone 0 1 to 1000 D value Specifies the D for this zone 0 to 200 lt mout value gt Specifies the manual output f
26. and fuse 5 Slide outthe removable plastic fuse holder from the drawer 6 Rotatethe fuse holder until the proper voltage indicator shows through the window 7 Re assemblethe line input assembly in the reverse order 8 Verifythe voltage indicator in the window ofthe line input assembly 9 Connectthe instrument power cord 10 Turn the line power switch On I Refer to FIGURE 8 2 N 100 120 220 240 V 10 Voltage 50 60 Hz 220 VA MAX 8 6 Fuse Replacement YTV Te C CAUTION 8 7 Factory Reset Menu 8 6 FuseReplacement 167 Line cord input Fuse 3 15 AT 250V 5x20mm FIGURE 8 2 Power fuse access Power switch Screwdriver o off i on slot Use this procedure to remove and replace a line fuse To avoid potentially lethal shocks turn off controller and disconnect it from AC power before performing these procedures For continued protection against fire hazard replace only with the same fuse type and rating specified for the line voltage selected Test fuse with an ohmmeter Do not rely on visual inspection of fuse Locate the line input assembly on the instrument rear panel See FIGURE 8 2 Turn the power switch Off 0 Remove the instrument power cord With a small screwdriver release the drawer holding the line voltage selector and fuse 5 Remove existing fuse s Replace with proper Slow Blow time delay fuse ratings as follows POD 100 120 220 240V 3 14AT250V 5x20 mm Re assemble the lin
27. rear rear plastic bottom bezel cover screw Loosen unshown bottom rear side cover Remove top screws cover screws both sides To remove Remove top top cover qu slide it to the rear both sides onthe tracks ol o FIGURE 7 3 Cover and option plate screws 3 Usea small Phillips screwdriver to remove the 2 top cover screws and 1 rear bottom screw FIGURE 7 3 4 Remove the rear plastic bezel The cover is tracked Slide the top cover to the rear onthe track to remove it 5 Remove the rear panel option plate screws and set aside Remove the rear panel option plate 6 With the instrument still standing on its face turn it to view the inside circuit board 7 Placethe option card into its position in the rear panel from inside the instru ment Orient the card so that the text printed on the option card panel is right side up when you view the Model 350 from the rear FIGURE 7 4 FIGURE 7 4 Correctly orient the option card thermocouple input option card shown 8 Attachthe card by starting both screws in a few threads before tightening either 9 Fully tighten both screws Model 350 Temperature Controller 10 D 0 5 D Attach connector SO arrow is on top 11 12 13 14 15 16 17 7 4 2 Option Card Installation 163 This step is not applicable to the 3062 option card Insert the 14 pin ribbon cable con ne
28. scanned input channels are scanned at a rate of 10 rdg s 100 ms rdg with the exception of any channel that is configured for 100 kO NTC RTD Channels configured for 100 kO NTC RTD are scanned at a rate of 5 rdg s 200 ms rdg when other channels are enabled or if it is reversing See TABLE 4 10 Number of scanner channels enabled Update vave 1 10 rdg s 100 ms rdg 2 5 rdg s 200 ms rdg 3 3 V rdg s 300 ms rdg 4 2 V rdg s 400 ms rdg 5 2 rdg s 500 ms rdg TABLE 4 10 Model 3062 4 channel scanner option reading update rate System control performance may be affected by a decreased update rate Filtering is affected by a decreased update rate Refer to section 4 4 9 for more information The Model 350 supports a variety of temperature sensors manufactured by Lake Shore and other manufacturers After the appropriate sensor type is selected section 2 2 an appropriate curve may be selected The Model 350 can use curves from several sources Standard curves are preloaded with every instrument and num bered 1 to 20 User curves numbered 21 to 59 can be used when a Sensor does not match a standard curve SoftCal calibrations are stored as user curves or you can enter your own curves from the front panel section 5 8 or computer interface sec tion 6 2 The complete list of sensor curves preloaded in the Model 350 is provided in TABLE 4 11 Lake Shore www lakeshore com
29. temperature controller Output 1 is designed for bulk heating and control at higher temperatures and can provide up to 75 W Output 2 is designed for control at very low temperatures and can provide up to 1 W They each include a large set of hard ware and software features making them very flexible and easy to use The heater outputs are well regulated DC outputs This provides quiet stable control for a broad range of temperature control systems in a fully integrated package The power ranges for each output provide decade steps in power 4 5 1 1 Max Current and Heater Resistance Output 1 Only The Model 350 heater output is designed to work optimally into a 25 O or 500 heater The Heater Resistance and Max Current parameters work together to limit the maximum available power into the heater This is useful for preventing heater dam age or limiting the maximum heater power into the system When using a 25 Q or 50 O heater set the Heater Resistance parameter accordingly The Max Current set ting will then provide multiple discrete current limit values that correspond to com mon heater power ratings The available current limits keep the output operating within the voltage compliance limit to ensure the best possible resolution These parameters work with the Heater Range parameter section 4 5 1 5 8 to provide safety and flexibility If you are not using a standard heater resistance set the Heater Resistance setting to 25 Oforanyresistan
30. the heater are turned off If Ramp is on and the setpoint is set to sensor units the ramping function will remain on but when another setpoint is entered the setpoint goes directly to the new setpoint value To bypass ramping and load the setpoint with the current temperature with the control loop displayed press and hold the Setpoint button for 3 s Menu Navigation Output Setup Output 1 2 3 or 4 Setpoint Ramping Off or On Default Off Interface Command RAMP To stop a ramp when the desired control loop is displayed press Setpoint then immediately press Enter This stops the ramp at the current setpoint but leaves the ramping function activated To continue the ramp enter a new setpoint Refer to sec tion 4 5 1 5 6 for details on setting the Setpoint parameter 4 5 1 5 8 Heater Range The Heater Range setting is used forturning a control output on as well as setting the output power range for the heater outputs All four outputs provide an Off setting for turning the output off The heater outputs 1 and 2 provide five ranges of settings which provide decade steps in power based on the maximum output power available to the connected heater Range 5 provides the maximum power and each successive lower range provides 10 times less power than the last Refer to section 2 14 1 for details on how to calculate the maximum output power The analog outputs 3 and 4 do not have multiple output ranges and only provide an
31. 1 6 Theload temperature should stabilize at a temperature below the setpoint The heater display should show a value greater than 0 and less than 100 If the load temperature does not stabilize below the setpoint do one ofthe following a Ifthe load temperature and heater display reading swing rapidly the proportional setting or possibly the heater range may be set too high Reduce the proportional setting orthe heater range and go back to step 6 b Iftheload temperature and heater display reading change very slowly a condition described as drift it is an indication of a proportional setting that is too low Increase the proportional setting and go back to step 6 2 14 3 Tuning Integral 2 14 3 TuningIntegral 41 7 Gradually increase the proportional setting by doubling it each time At each new setting allow time forthe temperature ofthe load to stabilize 8 Repeatstep 7 until you reach a setting in which the load temperature begins a sustained and predictable oscillation rising and falling in a consistent period of time See FIGURE 2 4 a The goal is to find the proportional value in which the oscillation begins do not turn the setting so high that temperature and heater output changes become extreme 9 Ifstep 8 is achieved complete steps 10 and 11 if not skip to step 12 10 Record the proportional setting and the amount oftime it takes for the load to change from one temperature peak to the next The time is calle
32. 1 Sensor Input Connector and Pinout sssssssssssssssssssese eee 47 3 5 2 Sensor lead Cable ceste tssiri Crnota EE rE I ala i eR RA NARRA 48 3 5 3 Grounding and Shielding Sensor Leads sss 48 3 5 4 Four Lead Sensor Measurement issues 48 3 5 5 Two Lead Sensor Measurement ce eee eee eee eee eee en 49 3 5 6 Lowering Measurement Noise 0c cece ccc e eee e eee cette eeennn nee 49 3 5 7 Sensor Polatity ceo n e eee eR Uc ERR ORNA AE eR ts 50 3 5 8 Capacitance Sensor Inputs Model 3061 ccc eee c cece cee e eee ees 50 3 5 8 1 Wiring Guarding and Shielding cc cee ee eeeee eee eee ene 51 3 5 9 Thermocouple Sensor Inputs Thermocouple Model 3060 51 3 5 9 1 Sensor Input Terminals 51 3 5 9 2 Thermocouple Installation 0 ccc ccc cece cece cece cece ee nnees 52 3 5 9 3 Grounding and Shielding 0 00 c cece eee ee ee ene eee enna nes 52 3 6 Heater Output Setup z diiuseneicte isa etae ume ia e babe R EE TE bee p pep ti a 52 3 6 1 Heater Output Description sss 52 3 6 1 1 OUTPUT oseeeeecotese n eed EE Cebu tt eie epe bPPMEHI E PR S 53 3 61 2 OUtpUE 2 ois pose Ree e IDE RO RODA EAEE AATE EA LOT A ER 53 3 6 2 Heater Output Connectors eccesso exe vaca na ESPERE DE GI es 53 3 6 3 HeaterO utput Wiring cxt eet io E Eanan eh ER EORR REY SERE EN edad 54 3 6 4 Heater Output NOISE icio pen eios exper ers ere RP REERE P EE RES 5
33. 166 8 6 Fuse Replacements isses orbes E ERRDPU IRE RR TIS YG EAR POS PC EAER 167 8 7 Factory Reset MEN sies io E Ee I EORR du e Ra re ERE Lada ERR 167 8 3 Default VAlWES ccveicsiceudnav eda XR EXE bx EN RR RR Y RE ROSE 168 8 7 2 Product Information ccc cece cece cece cece eeeeeeeeeeeeeennnannaa 169 8 3 Erro MESSIES iusso UR came aren adiavelads anon REED ER Ee STR exes 169 8 9 Calibration PEOCEQUFe eee e eue ERU pe EE a EERE Y ERRATA SAGEN 169 8 10 Rear Panel Connector Definition ssssssssssssssssss e 170 8 10 1 IEEE 488 Interface Connector sss 172 8 11 Electrostatic Discharge cusecesei espesor e er icon Yale EES ETE e bete aces 173 8 11 1 Identification of Electrostatic Discharge Sensitive Components 173 8 11 2 Handling Electrostatic Discharge Sensitive Components 174 8 12 Enclosure Top Remove and Replace Procedure cece cece eens 174 8 13 Record of Updates Made to the Firmware sse 176 8 14 Technical AGUIPIES o odor DERI Y bete RE Ue TRAE ERU 176 8 14 1 Contacting Lake Shore sssssssssssssssssss eee eee 176 8 14 2 Return of Equipment ssssssssssssssssssssssssee eee ee eee 177 8 14 3 RMA Valid Period prt it Rep t iO NRE EEEE ESPERA 177 8 14 4 Shipping Charges esirin riarann EE cece cece e eee eee eee 177 8 145 Restocking FEC ince RARE HS ERA RR YA EX E en 177 Lake Shore www lakeshore com CRYOTRONICS Model 350 Tempera
34. 3 2 Common Commands Common commands are addressed commands that create commonality between instruments on the bus All instruments that comply with the IEEE 488 standard share these commands andtheir format Common commands all begin with an aster isk They generally relate to bus and instrument status and identification Common query commands end with a question mark Model 350 common commands are detailed in section 6 6 1 and summarized in TABLE 6 6 6 2 3 3 Device Specific Commands Device specific commands are addressed commands The Model 350 supports a vari ety of device specific commands to program instruments remotely from a digital computer and to transfer measurements to the computer Most device specific com mands also work if performed from the front panel Model 350 device specific com mands are detailed in section 6 6 1 and summarized in TABLE 6 6 6 2 3 4 Message Strings A message string is a group of characters assembled to perform an interface function There are three types of message strings commands queries and responses The computer issues command and query strings through user programs and the instru ment issues responses Two or more command strings or queries can be chained together in one communication but they must be separated by a semi colon The total communication string must not exceed 255 characters in length A command string is issued by the computer and instructs the instrument to perform af
35. 31 2 10 65 Lead WITe i ioco HER RR PER Ip TOM RI LI ERE 32 2 10 7 lead Soldering ues u reor etr eee e TE E e FE RAV er E aspe 32 2 10 8 Thermal Anchoring Leads ssssssssssssssss e nett eee nena 33 21 0 9 Thermal Radlatioli e ces cite or E USER IPAE NER 33 2 10 10 Resistor Self Heating Versus Excitation c cece eee eee eee eens 33 2 11 Heater Selection and Installation cc cece cece e teen eens 34 2 11 1 Heater Resistance and POWEP 0 e cece eect eee eeeenn es 34 2 11 1 1 Main Heater Warmup Output 1 2 ccc e eee 34 2 11 1 2 Sample Heater Output 2 2 0 cece eens 34 2 11 1 3 Calculating Power Limits sess 34 211 14 Outputs 3 and4 i i ise tert e fa RP UER REINO TS 35 2 11 2 Heater EoCatlOn oso prec E Deb ba e ka ws En OC LU OE 35 2 113 Heater TYPES iecore y dome eq et IE oe enr E e ER niente 35 2 11 4 Heater WINING cere eere ctor ER a POR RARI VERRE LANDS 36 2 12 Consideration for Good Control ssssssssssssssssss tenes 36 2 12 1 Thermal Cond uctiVIty iix e cete nee rer xh eter dent e e genes 36 2 12 2 Thermal Lag sssr eese ese tede voe eee TR EARN YI Es Eee a seeders 36 2 12 3 Two Sensor Approach sssssssssessessrsseesressessesereresreesresees 36 2 12 4 Thermal MaSS perroner risens ten E a EIER A EE eene eene 36 2 12 5 System Mensis 37 2 13 PID CODEFO see ap enni senna ane ceateane PED RE herbis e a ns DRE sana e keh 37 2 13 1 Proportiona
36. 350 is attempting to configure the IP address parameters using the enabled methods 6 4 2 2 MAC Address The Media Access Controller MAC Address is a physical hardware address assigned to all Ethernet devices MAC addresses are 48 bits and are generally written as six groups of two hexidecimal digits separated by colons for example 01 23 45 67 89 AB Unlike IP addresses MAC addresses are tied to the device hard ware and cannot be changed Menu Navigation Read Only Interface View IP Config MAC Address 6 4 2 3 Viewing Network Configuration Parameters and DNS Parameters The currently configured network parameters are displayed individually in the View IP Config submenu These parameters could have been configured using either DHCP Auto IP or Static IP The LAN Status parameter shows which method was used for the current configuration When in an error state or in the intermediate Acquiring Address state the network configuration parameters will all be displayed as 0 0 0 0 Refer to section 6 4 1 1 through section 6 4 1 3 for details on network configuration parameters and DNS parameters Menu Navigation Read Only Interface Vieu IP Config P Interface View IP Config Subnet Mask Interface View IP Config Gateway IP Interface View IP Config Primary DNS IP Interface View IP Config Secondary DNS IP Interface View IP Config Actual Hostname Interface Vieu IP Config TCP Socket Port ATCP socket connection interface is
37. 5 2 for a list of operational status bits Operational Status Register Query OPSTR term bit weighting term nnn The integers returned represent the sum ofthe bit weighting ofthe operational sta tus bits These status bits are latched when the condition is detected This register is cleared when it is read Refer to section 6 2 5 2 for a list of operational status bits Output Mode Command OUTMODE output mode input powerup enable term n n n n output Specifies which output to configure 1 4 mode Specifies the control mode Valid entries O Off 1 Closed Loop PID 2 Zone 3 Open Loop 4 Monitor out 5 Warmup Supply lt input gt Specifies which input to use for control 0 None 1 A 2 B 3 C 4 D 5 Input D2 6 Input D3 7 Input DA 8 Input D5 for 3062 option Specifies whether the output remains on or shuts off after power cycle Valid entries O powerup enable off 1 powerup enable on lt powerup enable gt OUTMODE 1 2 1 0 term Output 1 configured for Zone control mode using Input A for the control input sensor and will turn the output off when power is cycled Modes 4 and 5 are only valid for Analog Outputs 3 and 4 Output Mode Query OUTMODE lt output gt term n output Specifies which output to query 1 4 lt mode gt lt input gt lt powerup enable term n n n referto command for description PID Input Format Remarks Example P
38. 50V 50V Heater load for max power 250 500 Heater load range 10 Q to 1000 Ranges 5 decade steps in power Heater noise 1 2 uA RMS dominated by line frequency and its harmonics Grounding Output referenced to chassis ground Heater connector Dual banana Safety limits Curve temperature power up heater off short circuit protection TABLE 1 5 Output 1 Type Variable DC current source D A resolution 16 bit Max power 1W Max current 100 mA Voltage compliance min 10V Heater load for max power 1000 Heater load range 25 Q to2k 0 Ranges 100 Q load 1 W 100 mW 10 mW 1 mW 100 pW Heater noise 0 00526 of range Grounding Output referenced to measurement common Heater connector Dual banana Safety limits Curve temperature power up heater off short circuit protection TABLE 1 6 Output 2 Lake Shore www lakeshore com CRYOTRONICS 10 CHAPTER 1 Introduction 1 6 5 Front Panel Model 350 Temperature Controller 1 6 4 2 Analog Outputs Outputs 3 and 4 Control type Warm up heater mode settings Warm up percentage Warm up mode Monitor Out settings Scale Data source Settings Type Update rate Range Resolution Accuracy Noise Maximum current Maximum power Minimum load resistance Connector Display Number of reading displays Display units Reading source Display update rate Temperature display resolution Sensor units display reso
39. B Sensor input B C Sensor input C D Sensor input D D1 Sensor input D channel 1 D2 Sensor input D channel 2 D3 Sensor input D channel 3 D4 Sensor input D channel 4 D5 Sensor input D channel 5 K Temperature in kelvin c Temperature in degrees Celsius V Sensor units of volts Q Sensor units of ohms kQ Sensor units of kilohms mV Sensor units of millivolts nF Sensor units of nanofarads TABLE 4 5 Display annunciators 4 2 3 General Keypad There are five basic keypad operations direct operation menu navigation number Operation entry alpha numeric entry and setting selection m Direct Operation the key function occurs as soon as you press the key these include the Setpoint P D Manual Out and All Off keys m Menu Navigation each menu has a list of configurable parameters Menus that apply to multiple entities for example Input Setup could apply to Input A B C or D have a first level selection to determine which entity to configure for instance Input C Once the first level selection is made the list of menu parameters is dis played The parameter labels are displayed on the left and the current value of each parameter is displayed on the right In this screen use the A and W keys to move the highlight up or down respectively Press Enter to enter the setting mode forthe highlighted parameter The type of setting mode depends on the type of parameter highlighted The possible setting modes are Number Entry
40. CHAPTER 8 Service 8 10 Rear Panel Connector Definition Model 350 Temperature Controller The sensor input heater output terminal block USB Ethernet and IEEE 488 connec tors are defined in FIGURE 8 3 through FIGURE 8 8 For thermocouple connector details referto FIGURE 3 8 FIGURE 8 3 Sensor input A through D 1 l Current 2 V Voltage 3 None Shield 4 V Voltage 5 I Current 6 None Shield TABLE 8 3 Sensor input A through D connector details OUTPUT 1 HEATER GND OUTPUT 2 HEATER HI LO HI LO 75 WMAX 1WMAX FIGURE 8 4 Heater output connectors 8 10 RearPanelConnectorDefinition 171 Use screwdriver to lock or unlock wires Slides into slot at rear of Model 350 Insert wire into slot FIGURE 8 5 Terminal block for relays and Output 3 and 4 Description Output 3 Output 3 Output 4 Output 4 Relay 1 normally closed Relay 1 common Relay 1 normally open Relay 2 normally closed Relay 2 common ne Relay 2 normally open TABLE 8 4 Terminal block pinand connector details 21 Tl 3 4 FIGURE 8 6 USB pin and connector details Description 1 vec 5 VDC 2 D Data 3 D Data 4 GND Ground TABLE 8 5 USB pin and connector details Lake Shore www lakeshore com CRYOTRONICS 172 CHAPTER 8 Service 8 10 1 IEEE 488 Interface Connector Model 350 Temperature Controller FIGURE
41. Cards for More Inputs and a Wider Range of Applications 1 2 3 Four PID Controlled Outputs Model 350 Temperature Controller In short the Model 350 cryogenic temperature controller brings a new level of power precision and performance to critical low temperature physics research Itis ideal for use with He 3 systems adiabatic demagnetization refrigerators ADRs certain dilu tion refrigerators and many other applications demanding low thermal power and high measurement precision Designed to support a broad range of sensortypes the Model 350 is performance optimized for use over the entire temperature range of Cernox sensors making it the instrument of choice for ULT environments as well as other cryogenic systems where errors due to magneto resistive or radiation effects need to be minimized The Model 350 comes with four standard sensor inputs supporting Cernox ruthe nium oxide platinum RTDs and other NTC RTD sensors Inputs can be configured to accept any ofthe supported input types Each sensor input channel has its own cur rent source providing fast settling times The four sensor inputs are optically isolated from other circuits to reduce noise and to provide repeatable sensor measurements Current reversal eliminates thermal electromotive force EMF errors in resistance sensors Nine excitation currents facilitate temperature measurement and control down to 100 mK with the nominal temperature range using Cernox
42. Definition of returned parameter Syntax of returned parameter INCRV Input Format Format Brief description of query Input Curve Number Query INCRV input term a input Specify input A D Returned lt curve number gt term nn FIGURE 6 13 Sample query format Model 350 Temperature Controller 6 6 CommandSummary 137 Function Command Function Page CLS Clear Interface Cmd 138 INNAME Sensor Input Name Query 147 kESE Event Status Enable Register Cmd 138 INTSEL Interface Select Cmd 147 KESE Event Status Enable Register Query 138 INTSEL Interface Select Query 147 kESR Standard Event Status Register Query 138 INTYPE Input Type Parameter Cmd 148 kIDN Identification Query 139 INTYPE Input Type Parameter Query 149 kOPC Operation Complete Cmd 139 KRDG Kelvin Reading Query 149 OPC Operation Complete Query 139 LEDS Front Panel LEDS Cmd 149 kRST Reset Instrument Cmd 139 LEDS Front Panel LEDS Query 149 kSRE Service Request Enable Register Cmd 139 LOCK Front Panel Keyboard Lock Cmd 149 KSRE Service Request Enable Register Query 139 LOCK Front Panel Keyboard Lock Query 149 STB Status Byte Query 140 MDAT Minimum Maximum Data Query 150 TST Self Test Query 140 MNMXRST Minimum and Maximum Function Reset Cmd 150 KWAI Wait to Continue Cmd 140 M
43. InputA 2 4 001K 7K 70 0 40 0 0 0 0 Low 0 7 K Min InputA 1 OK 4K 50 0 50 0 0 0 0 Low 0 5 K Min InputA TABLE 5 2 Zone settings example Sensor accuracy and placement will affect how smoothly the transition from one feed back sensor to another is performed A large difference between the temperature read ings of each sensor at the time of transition could cause a temporary instability in the temperature control due to the sudden large error introduced into the control equation It is highly recommended to use the Setpoint Ramping feature when using the Control Input zone parameter to change sensor inputs Otherwise a setpoint change may cause a control input sensor to be used outside of its usable range which will cause an overload condition to shut down the control loop Lake Shore www lakeshore com CRYOTRONICS 88 CHAPTER 5 Advanced Operation Zone 10 Zone 09 Zone 08 Zone 07 Zone 06 Zone 05 Zone 04 Zone 03 Zone 02 Zone 01 Proportional Integral Derivative MHP Output 0 1 1000 0 1 1000 0 200 0 100 Proportional Integral Derivative MHP Output 0 1 1000 0 1 1000 0 200 0 100 Proportional Integral Derivative MHP Output 0 11000 0 1 1000 0 200 0 100 Proportional Integral Derivative MHP Output 0 1 1000 0 11000 0 200 0 100
44. Model350 to bipolar mode m Some power supplies can be damaged if there is a programming voltage present attheir input when they are turned off This can happen ifthe Model 350 and power supply use a different source of line powerorare turned on and off individ ually It can be avoided if the two instruments share a switched power strip B The heater and wiring in the system must be rated for both the maximum current and maximum voltage provided by the power supply The Model 350 can be set to warm up using lessthan full power ifthe load will nottolerate the full power of the supply 3 6 5 3 Connecting to the Model 350 The voltage programming cable attaches to the removable terminal block on the rear panel of the Model 350 FIGURE 3 10 Output number and polarity ofthe output leads are indicated on the silk screen The negative terminals are connected inter nally to the instrument chassis to provide a ground reference b od OUTPUTS 30VDC 3A ANALOG RELAY1 RELAY2 FIGURE 3 10 Output terminal block Inthe most basic configuration a two conductor cable connects directly from the output terminals to the power supply programming input Copper wire size 20 AWG to 26 AWG is recommended Lake Shore www lakeshore com CRYOTRONICS 56 CHAPTER 3 Installation Model 350 Temperature Controller 3 6 5 4 Programming Voltages Under 10 V A voltage divider FIGURE 3 11 can be used to reduce the control output voltage if the p
45. Navigation mode if in the last position Use the key to enter the whitespace character Model 350 Temperature Controller 4 3 Display Setup 4 3 1 Display Modes 4 3 DisplaySetup 61 m Setting Selection allows you to select from a list of values During a selection sequence use the A or V keys to select a parameter value To select the high lighted parameter as the new setting press Ente the setting is saved and the mode returns to Menu Navigation Press Escape at any time while the parameter list is displayed tocancel any changes and return to Menu Navigation mode The intuitive front panel layout and keypad logic bright graphic display and LED indicators enhance the user friendly front panel interface of the Model 350 The Model 350 offers a bright graphic liquid crystal display with an LED backlight that simultaneously displays up to eight readings The Model 350 provides several display modes designed to accommodate different instrument configurations and user preferences The Four Loop display mode offers large format sensor readings of each ofthe four sensor inputs as well as setpoint and heater output information for associated outputs all on one screen The Input display modes provide detailed information about the relevant sensor input and the associ ated output The Custom display mode provides a means for you to assign different types of information to specific sections ofthe display Menu Navigation Displa
46. R limiting the effect of self heating In autorange mode the sensor excitation setting is the max imum not the actual voltage The autorange algorithm includes a hysteresis band to prevent instability when the sensor resistance is at a range boundary Itis possible forthe instrument to choose a different excitation current when approaching a value from below than it chooses when approaching from above Autorange should not be used when a specific exci tation current is critical 2 4 2 2 Manual Excitation Mode The user specifies a fixed resistance range which defines the excitation current The instrument selects the appropriate voltage gain forthe selected resistance range The instrument keeps the current and resistance range constant when a manual range is selected In this mode it is easier to calculate the actual power in the sensor P I x R because the true current is displayed alongside the resistance range in the menu The Model 350 has full scale resistance ranges from 10 O to 300 kO Most ranges are available with either a 10 mV or 1 mV excitation The goal is to use enough excitation to maintain reasonable accuracy resolution and settling time without putting too much heat into the sensor Usually the 10 mV autorange excitation mode results in the best performance but as temperatures decrease the 1 mV autorange excitation mode may result in better performance by limiting the self heating ofthe sensor As temperatures further d
47. Shore temperature monitors and controllers The ANALOG com mand name is also named as such for backward compatibility Lake Shore www lakeshore com CRYOTRONICS 142 ANALOG Input Format Returned Format AOUT Input Format Returned Format Remarks ATUNE Input Format Example Remarks BRIGT Input Format Remarks BRIGT Input Returned Format CRDG Input Format Returned Format Remarks Model 350 Temperature Controller CHAPTER 6 Computer Interface Operation Monitor Out Parameter Query ANALOG output term n output Specifies which unpowered analog output to query the Monitor Out parameters for 3 or 4 lt input gt lt units gt lt high value gt lt low value polarity term n n tnnnnn tnnnnn n refer to command for definition Analog Output Data Query AOUT output term n output Specifies which unpowered analog output to query 3 or 4 output percentage term tnnn n Returns the output percentage of the unpowered analog output Autotune Command ATUNE lt output gt lt mode gt term n n output Specifies the output associated with the loop to be Autotuned 1 4 lt mode gt Specifies the Autotune mode Valid entries O P Only 1 P and l 2 P l andD ATUNE 2 1 term initiates Autotuning of control loop associated with output 2 in P and I mode If initial conditions required to Autotune the specified loop are not met an Autotun
48. SoftCal Curve Cmd 155 DISPLAY Display Setup Query 145 SETP Control Setpoint Cmd 155 FILTER Input Filter Parameter Cmd 145 SETP Control Setpoint Query 155 FILTER Input Filter Parameter Query 145 SRDG Sensor Units Input Reading Query 156 HTR Heater Output Query 145 TEMP Thermocouple Junction Temperature Query 156 HTRSET Heater Setup Cmd 146 TLIMIT Temperature Limit Cmd 156 HTRSET Heater Setup Query 146 TLIMIT Temperature Limit Query 156 HTRST Heater Status Query 146 TUNEST Control Tuning Status Query 156 IEEE IEEE 488 Parameter Cmd 146 WARMUP Warmup Supply Parameter Cmd 157 IEEE IEEE 488 Interface Parameter Query 146 WARMUP Warmup Supply Parameter Query 157 INCRV Input Curve Number Cmd 147 WEBLOG Website Login Parameters 157 INCRV Input Curve Number Query 147 WEBLOG Website Login Parameter Query 157 INNAME Sensor Input Name Cmd 147 ZONE Control Loop Zone Table Parameter Cmd 158 ZONE Output Zone Table Parameter Query 158 TABLE 6 6 Command summary Lake Shore www lakeshore com CRYOTRONICS 138 CHAPTER 6 Computer Interface Operation 6 6 1 Interface Commands KCLS Input Remarks ESE Input Format Remarks Example X ESE Input Returned Format ESR Input Returned Format Remarks Model 350 Temperature Controller This section lists the interface commands in alphabetical order Begins common interface command Required to identify qu
49. Thermocouple NE Input Option Card Static Primary DNS 0 0 0 0 Room comp On Static Secondary DNS 0 0 0 0 Room cal Cleared Preferred hostname LSCI 350 Input Setup Capacitance Option Card Webiusername TU Web password Temperature coefficient Positive Default Output mode Closed loop PID off for Output 3 and 4 Input A for Output 1 Input B for Output 2 Control input P Rane EM d dand4 p Relay Off Power up enable Off Mode Unlocked Heater out display Current Lock code 123 Proportional P 50 0 Display mode Custom Integral I 20 0 Number of locations 2 large Derivative D 0 0 Location 1 source InputA Manual Output 0 000 Location 2 source Input B Heater range Off Location 3 source Input C Setpoint value 0 000K Location 4 source Input D Remote Local Local Location 5 source InputA Upper boundary 0 000 K Location 5 units Sensor Proportional P 50 0 Location 6 source Input B Integral I 20 0 Location 6 units Sensor Derivative D 0 00 Location 7 source Input C Manual output 0 000 Location 7 units Sensor Range Off Location 8 source Input D Ramp rate 0 100 K min Location 8 units Sensor Control input Default Contrast 28 TABLE 8 1 Default values Model 350 Temperature Controller 8 7 2 Product Information 8 8 Error Messages 8 9 Calibration Procedure 8 7 2 ProductInformation 169 Product information for your instrum
50. a controller that has a bipolaroutput to take full advantage ofthis The Model 350 can be configured for bipolar control on Outputs 3 and 4 Closed loop PID control works the same in bipolar mode as it does in unipolar mode except that the output can go negative instead of stopping at zero Refer to section 5 4 to setup Output 3 and 4 in bipolar mode The Model 350 cannot drive a thermoelectric device directly Most thermoelectric devices require high current approximately 3 A and low voltage typically 10 V Output 3 and 4 are capable of 10 V and 100 mA An external power amplifier is nec essary to boost the power up to a level that will effectively control the thermoelectric device Refer to section 3 6 5 for more information on using an external power ampli fier with Outputs 3 and 4 Lake Shore www lakeshore com CRYOTRONICS 44 CHAPTER 2 Cooling System Design and Temperature Control Model 350 Temperature Controller 3 1General 45 Chapter 3 Installation 3 1 General 3 2 Inspection and Unpacking 3 3 Rear Panel Definition This chapter provides general installation instructions forthe Model 350 tempera ture controller Please read this entire chapter before installing the instrument and powering iton to ensure the best possible performance and maintain operator safety For instrument operating instructions referto Chapter 4 and Chapter 5 For computer interface installation and operation refer to Chapter 6 I
51. and holding A B C or D Interface Command DISPLAY 4 3 1 DisplayModes 63 4 3 1 4 Custom Display Mode The custom display mode provides the ability to customize the displayed front panel information to your preference As with the input display modes the custom display mode shows sensor input information in the top half of the screen and control loop information in the bottom half The sensor input information can be customized to display two large character sensor readings with names four large character sensor readings without names or eight small character format sensor readings without names Each displayed reading can use any sensor asthe input and can be displayed in units of kelvin Celsius sensor min or max Menu Navigation Display Setup Display Mode Custom Interface Command DISPLAY m Locations depending on the Number of Displays parameter there can be any where from two to eight display locations for displaying sensor readings The placement of a given display location on the front panel LCD depends on the Number of Displays setting FIGURE 4 5 of Off FIGURE 4 5 lop to bottom Model 35U screen images showing 2 4 and 8 display locations m Number of Custom display locations the Number of Displays parameter determines how many sensor readings are displayed as well as the character size of the dis played readings If 2 Large is selected then two large character readings are displayed along wi
52. are listed in TABLE 5 3 Typical curve parameters for common sensors are listed in TABLE 5 4 Read this section completely and gather all necessary data before beginning the process If the curve you wish to enter has similar parameters as an existing curve first copy the similar curve as described in Section 5 2 4 to a new location then edit the curve to the desired parameters 5 9 1 EditCurve 97 To perform the Edit Curve operation follow this procedure 1 Press Curve Entry 2 Scrollto Edit Curve and press Enter 3 Scrolltothe desired curve and press Enter again 4 Editthe curve header parameters using the standard keypad operation methods described in section 4 2 3 The curve breakpoints are entered in a slightly differ ent way than other menu parameters 5 Toaccessthe breakpoint data highlight Curve Points in the Curve Edit menu screen and press Enter to enter the Curve Point entry screen The Curve Point entry screen contains a scrollable list of all curve breakpoint pairs in the selected curve There are three columns in the list From leftto right the columns are breakpoint number breakpoint sensor value breakpoint temperature value Ini tially the highlight is on the first breakpoint number Menu Navigation Curve Entry Edit Curve Interface Command CRVHDR 5 9 1 1 Edit a Breakpoint Pair To edit a breakpoint pair follow this procedure 1 Select a breakpoint pairto edit Do this by scrolling to the desired
53. be any breakpoint locations left blank in the middle ofa curve The search routine in the Model 350 interprets a blank breakpoint as the end of the curve There are five operations associated with front panel curve entry Edit curve View Curve Erase Curve Copy Curve and SoftCal as detailed below Description F Edit Curve allows you to edit curves at any user curve location Stan Edit Curve 5 9 1 dard curves cannot be changed View Curve allows you to view any curv ny curve location N VieWEUIve ew Curve allows you to view any curve at any curve loc 0 592 curves can be changed Erase Curve allows you to delete a curve from any user curve location Erase Curve 5 9 3 Standard curves cannot be erased Copy Curve allows you to copy a curve from any location to any user Copy Curve Py d y PY MEM M ded any ig 5 9 4 curve location Curves cannot be copied into standard curve locations SoftCal allows you to create a new temperature curve from a standard SoftCal 5 10 curve and known data points entered by the user TABLE 5 5 Front panel curve entry operations Menu Navigation Curve Entry gt Edit Curve View Curve Erase Curve Copy Curve SoftCal Use the Edit Curve operation to enter a new curve or edit an existing user curve Only user curves 21to 59 can be edited Entering the identification parameters associ ated with the curve is as important as entering the breakpoints Curve header param eters
54. cooling system can be much different from what is used inside Between the instrument and vacuum shroud heat leak is not a concern In this case choose cabling to minimize error and noise pick up Larger con ductor 22 AWG to 28 AWG stranded copper wire is recommended because it has low resistance yet remains flexible when several wires are bundled in a cable The arrangement of wires in a cable is also important For best results voltage leads V and V should be twisted together and current leads I and l should be twisted together The twisted pairs of voltage and current leads should then be covered with a braided or foil shield that is connected to the shield pin of the instrument This type of cable is available through local electronics suppliers Instrument specifications are given assuming 3 m 10 ft of sensor cable Longer cables 30 m 100 ft or more can be used but environmental conditions may degrade accuracy and noise specifica tions Refer to section 2 10 6 for information about wiring inside the cryostat The sensor inputs are isolated from earth ground to reduce the amount of earth ground referenced noise that is present on the measurement leads Connecting sen sor leads to earth ground on the chassis of the instrument or in the cooling system will defeat that isolation Grounding leads on more than one sensor prevents the sen sor excitation current sources from operating Shielding the sensor lead cable is important to kee
55. electronic parts are more ESD sensitve than others ESD levels of only a few hundred volts may damage electronic components such as semiconductors thick and thin film resistors and piezoelectric crystals during testing handling repair or assembly Discharge voltages below 4000 V cannot be seen felt or heard The following are various industry symbols used to label components as ESD sensitive gt A CRUTION FO tas auiem FIGURE 8 9 Symbols indicating ESD sensitivity Lake Shore www lakeshore com CRYOTRONICS 174 CHAPTER 8 Service 8 11 2 Handling Electrostatic Discharge Sensitive Components 8 12 Enclosure Top Remove and Replace Procedure A WARNING C CAUTION Model 350 Temperature Controller Observe all precautions necessary to prevent damage to ESDS components before attempting installation Bring the device and everything that contacts it to ground potential by providing a conductive surface and discharge paths As a minimum observe these precautions m De energize or disconnect all power and signal sources and loads used with unit m Place the unit on a grounded conductive work surface m Thetechnician should be grounded through a conductive wrist strap or other device using 1 M series resistor to protect operator m Ground any tools such as soldering equipment that will contact the unit Con tact with the operator s hands provides a sufficient ground for tools that are oth erwise electrically
56. enables automatic switching of sensor inputs and scales current excitation through ten different preloaded temperature zones the Model 350 provides continuous mea surement and control over the entire temperature range required With remote control and automated features the Model 350 will simplify your tem perature control processes and increase your productivity in the laboratory The Model 350 temperature controller includes Ethernet USB and IEEE 488 inter faces In addition to gathering data nearly every function ofthe instrument can be controlled through a computer interface Ethernet provides the ability to access and monitor instrument activities via the internet from anywhere in the world allowing distributed sharing ofthe controller and the controlled system You can download the Lake Shore curve handler software to your computer to easily enter and manipulate sensor calibration curves for storage in the instrument s nonvolatile flash memory Each sensor input has a high and low alarm that offer latching and non latching oper ation The two relays can be used in conjunction with the alarms to alert you of a fault condition and perform simple on off control Relays can be assigned to any alarm or operated manually Choosing appropriate PID control settings for a closed loop sys tem can be tedious but the Model 350 provides the temperature control loop auto tuning feature to simplify the process It s an automated process that measur
57. error in sensor measurements that comes from within Self heating will occur when the power from excitation current is large enough to warm the sensor above the temperature of its surroundings The effect is most noticeable at low tem peratures because the thermal conduction becomes very poor The self heating error can be determined by either calculating the error using the thermal resistance of the sensor or by lowering the excitation current until self heating does not cause change in measured resistance To measure the effect of self heating use the current ranges available in the Model 350 Begin by cooling the sensor to the desired temperature and measure its value using the highest current excitation available for the sensor being measured Step up one resistance range dropping the current by about 2 3 and measure the sensor resistance again A change in measured value indicates self heating was present on the higher current range Continue increasing the resistance range decreasing the current until the change is no longer significant If there is still a measured change at the lowest current setting then a different sensor may need to be chosen A variety of sensor packages and typical resistances are available so a sensor with a lower typical resistance or more thermal resistance at the desired temperature may be required Thermal resistance changes with temperature so this process must be repeated at several temperatures Not everyone
58. feature captures and stores the highest Max and lowest Min reading taken since the last reset The Preferred Units parameter underthe Input Setup menu determines the units used for capturing Max and Min Max and Min are always being captured so there is no need to turn the feature on or off The readings are reset when the instrument is turned off sensor input parameters are changed or the Max Min Reset key is pressed Menu Navigation Max Min Reset Once the sensor inputs have been configured section 4 4 the outputs can be config ured The Output Setup menu is used to create control loops for controlling tempera ture whether using feedback closed loop or manually setting the output open loop This section describes how to operate the output and control features and how to set control parameters Each control parameter should be considered before turn ing on a control loop output or the instrument may not be able to perform the most simple control functions A good starting point is deciding which control loop to use whether to operate in open or closed control mode and which tuning mode is best for the application Other parameters fall into place once these have been chosen Section 2 13 ofthis manual describes the principals of closed loop proportional inte gral and derivative PID control 4 5 1 Heater Outputs 4 5 1 HeaterOutputs 75 Heater Outputs 1 and 2 are traditional control loop heater outputs for a cryogenic
59. gt Specifies the curve temperature limit in kelvin lt coefficient gt Specifies the curves temperature coefficient Valid entries 1 negative 2 positive Configures the user curve header The coefficient parameter will be calculated auto matically based on the first 2 curve datapoints It is included as a parameter for com patability with the CRVHDR query CRVHDR 21 DT 470 00011134 2 325 0 1 term configures User Curve 21 with a name of DT 470 serial number of 00011134 data format of volts versus kelvin upper temperature limit of 325 K and negative coefficient Curve Header Query CRVHDR curve term nn curve Valid entries 1 59 lt name gt lt SN gt lt format gt lt limit value gt lt coefficient gt term s 15 s 10 n nnn nnn n refer to command for description Curve Data Point Command CRVPT lt curve gt lt index gt lt units value gt lt temp value term nn nnn Ennnnnn rnnnnnn curve Specifies which curve to configure Valid entries 21 59 index Specifies the points index in the curve Valid entries 1 200 units value Specifies sensor units for this point to 6 digits temp value Specifies the corresponding temperature in kelvin for this point to 6 digits Configures a user curve data point CRVPT 21 2 0 10191 470 000 N term sets User Curve 21 second data point to 0 10191 sensor units and 470 000 K Curve Data Point Query CRVPT curve index term nn nnn cur
60. heating begins to dominate overall measurement uncertainty There are several ways to decrease self heating such as increasing the sensor s ther mal transfer selecting a sensor with lower resistance lower power dissipation and reducing the excitation current by changing the instrument range Many times the sensor thermal characteristics are defined by the type of sensor selected and cannot be changed Magnetic fields sensitivity requirements noise performance mounting considerations cost and availability may drive a sensor selection Once a sensor is selected the excitation current should be chosen to balance errors from self heating and other sources of resolution and uncertainty Self heating calculations are explained in section 2 x x Fora typical CX 1010 at 100 mK with electronic resistance R equal to 21 3890 the thermal resistance R is 2E 9Q see Appendix E Temperature Measurement System in the Temperature Control Catolog At 10 nA excitation current the typical self heating error would be ATg 2ReRy 10 nA2 21 389 2E 9 44 3mK Instrument electronic accuracy can be calculated from the specifications listed in TABLE 1 3 The accuracy depends on the range selected and the sensor reading TABLE 1 3 lists this as a reading and range error such as 100 0 0 04 rdg for NTC RTD 1mV 0 Q to 100 kQ input range 10nA excitation current The accuracy in ohms can then be converted to temperature using the sensitivity
61. include a menu navigation section Menu Navigation This section is intended to be a quick guide through the necessary key presses to arrive at and set the desired features See FIGURE 4 2 and TABLE 4 1 for an explana tion ofthe conventions used in the menu navigation A B C D E MEME Input Setup gt Input A B C or D Enter gt Room Compensation Off or On FIGURE 4 2 Menu navigation example Item Convention Explanation Typically the first word in the menu navigation is in bold type which indicates the first A Bold key you will need to press The arrow indicates that the screen is advancing to the next screen In the menu navi B gt gation the item that follows the arrow is the next item you would see on the screen or the next action that you will need to perform Often the words that follow the arrow are in italic type The italic type indicates that C Italic type p there is a setting that needs to be selected The items that follow the italicized word and which are in parentheses are the avail D Parentheses i able selections to which you can set the desired feature E Enter Press Enter on the keypad TABLE 4 1 Menu navigation key Lake Shore www lakeshore com CRYOTRONICS 58 CHAPTER 4 Operation 4 2 Front Panel This section provides a description of the front panel controls and indicators for the Description Mgdetase 4 2 1 Keypad The keypad is divided into two sections The Direct Oper
62. m SRQ Service Request tells the bus controller that the Model 350 needs interface service A multiline command asserts a group of signal lines All devices equipped to imple ment such commands do so simultaneously upon command transmission These commands transmit with the Attention ATN line asserted low The Model 350 recog nizes two multiline commands m LLO Local Lockout prevents the use of instrument front panel controls m DCL Device Clear clears Model 350 interface activity and puts it into a bus idle state Finally addressed bus control commands are multiline commands that must include the Model 350 listen address before the instrument responds Only the addressed device responds to these commands The Model 350 recognizes three ofthe addressed bus control commands m SDC Selective Device Clear the SDC command performs essentially the same function as the DCL command except that only the addressed device responds m GTL Go To Local the GTL command is used to remove instruments from the remote mode With some instruments GTL also unlocks front panel controls if they were previously locked out with the LLO command 6 2 3 IEEE 488 2 Command Structure 107 m SPE Serial Poll Enable and SPD Serial Poll Disable serial polling accesses the Service Request Status Byte Register This status register contains important operational information from the unit requesting service The SPD command endsthe polling sequence 6 2
63. of additional Cernox sensors for supplemental monitoring For convenient integration into a wide range of systems the Model 350 offers four PID controlled outputs Variable DC current source outputs include a 75 W output for direct control ofthe typical main warm up heater and a 1 W output for fine control of the sample heater Two additional 1 W variable DC voltage source outputs can be used to power auxiliary devices like a still heater in a dilution refrigerator or to con trol a magnet power supply driving an ADR The ability to dynamically select an input to associate with the controlled output provides additional flexibility in setting up the control scheme 1 2 4 Precision Temperature Control 1 3 Simple and Increased Productivity 1 3 1 Three Interfaces for Remote Control 1 3 2 Simple Automation 1 4 Performance You Can Count On 1 4 1 Balanced Current Source 1 4 2 Common Mode Reduction Circuit 1 2 4 Precision Temperature Control 3 The Model 350 calculates the precise control output based on your temperature set point and feedback from the control sensor You can manually set the PID values for fine control orthe temperature control loop autotuning feature can automate the tuning process for you The setpoint ramp feature provides smooth continuous set point changes and predictable setpoint approaches without the worry of overshoot or excessive settling times When combined with the zone setting feature which
64. of the following equations Sqrt P R and 50V R whereP is the maximum allowable power R is the heater resistance The load power limit and voltage compliance limit of the heater output 50 V are in place at the same time so the lower calculated current is the correct Max Current setting Lake Shore www lakeshore com CRYOTRONICS 76 CHAPTER 4 Operation Example 1 A 50 O 30 W heater is connected to Output 1 Power Limit Voltage Compliance Limit Squrt P R 2 50 V R Squrt 30 W 50Q 1250V 500 120 77A I 1A User Max Current should be set to the smaller of the two or 0 77 A In this example the desired 30 W of power is available to the heater Example 2 A75 Q 50 W heater is connected to Output 1 Power Limit Voltage Compliance Limit Squrt P R 12 50 V R Squrt 50 W 75Q 1250V 750 1 0 81A 1 0 66A User Max Current should be set to the smaller of the two or 0 66 A In this example only 33 W of the desired 50 W of power is available to the heater To enter a User Max Current first set the Heater Resistance setting to 25 O for any resistance less than 50 O orto 50 O for any higher heater resistance Set the Max Cur rent setting to User The User Max Current setting now becomes available in the Out put Setup menu Enter the calculated current limit value in the User Max Current parameter Heater Resistance Max Current 100 250 300 1 732A 430W 75W x x x X 1 667
65. ofthe instrument and the safety of operators S 100 120 220 240 V 10 Voltage 3 15 AT 250V 50 60 Hz 220 VA MAX 5x20mm FIGURE 3 2 Line input assembly 3 4 1 Line Voltage The Model 350 has four different AC line voltage configurations so that it can be oper ated from line power anywhere in the world The nominal voltage and voltage range of each configuration is shown below The recommended setting for 230 V operation is 240 V Nominal Minimum Maximum 100V 90V 110V 120V 108V 132V 220V 198V 242V 240V 216V 264V TABLE 3 1 Line voltage 1 CAUTIO N AC line voltage is set at Lake Shore but it is good to verify that the AC line voltage indica tor in the fuse drawer window is appropriate before turning the instrument on The instrument may be damaged if turned on with the wrong voltage selected Also remove and verify that the proper fuse is installed before plugging in and turning on the instru ment Refer to section 8 5 for instructions on changing the line voltage configuration 3 4 2 Line Fuse and The line fuse is an important safety feature of the Model 350 If a fuse ever fails it is Fuse Holder important to replace it with the value and type indicated on the rear panel for the line voltage setting The letter T on the fuse rating indicates that the instrument requires a time delay or slow blow fuse Fuse values should be verified any time line voltage configuration is changed Refer to sec
66. parameters when choosing a sensor The first is experimental temperature range Some sensors can be damaged by tempera tures that are eithertoo high ortoo low Manufacturer recommendations should always be followed Sensor sensitivity changes with temperature and can limitthe useful range of a sen sor Itis important not to specify a range largerthan necessary If you perform an experiment at liquid helium temperature a very high sensitivity is needed for good measurement resolution at that temperature That same resolution may not be required to monitor warm up to room temperature Two different sensors may be required to tightly cover the range from base temperature to room temperature but lowering the resolution requirement on warm up may allow a less expensive 1 sensor solution Anotherthing to consider when choosing a temperature sensor is that instruments like the Model 350 are not able to read some sensors over their entire temperature range Lake Shore sells calibrated sensors that operate down to 20 millikelvin mK but the Model 350 is limited to above 100 mK in its standard configuration Temperature sensor sensitivity is a measure of how much a sensor signal changes when the temperature changes It is an important sensor characteristic because so many measurement parameters are related to it Resolution accuracy noise floor and even control stability depend on sensitivity Many sensors have different sensitiv ities at differen
67. point Loops are also the primary means of coupling H field noise Conductive shields do not reduce the effects of H fields Two ways to minimize H field coupling are to reduce the loop area or breakthe loop as described with ground loops Loop area can be minimized by tightly twisting lead pairs both voltage and current within the shielded cables This reduces loop area and exposes both leads to the same common mode effects which are rejected by the measurement input 2 4 4 2 Shields Shields provide a low impedance path to measurement common to block E field noise from getting to the signal leads Shield pins are provided in the input connectors as attachment points for the shield conductors in lead cables Shielding individual leads inside a cryostat is difficult because of limited space and the potential for heat leak Cable shields are usually connected to the experimental Dewar to create a fara day shield around the measurement 2 4 4 3 Electrical Isolation The precision analog front end is electrically isolated from digital circuitry and chassis ofthe instrument by optocouplers This can improve measurements in two ways First isolation makes it more difficult for digital noise from control circuits and com puter interfaces to affect the measurement leads Second isolation separates the instrument measurement from Earth ground to break potential ground loops 2 4 5 Measurement Speed and Filtering 2 5 Noise Sources 2 5 1 In
68. rdg 10mV 00to300 300 pA 0 1mQ 0 3 mQ 10 0020 0 03 mQ O 001960frdg C 0 6 mQ 0 06 of rdg 00 to 1000 100 pA 1mQ 1mQ 0 01 0 0 1 mQ 0 001 of rdg C 2mQ 0 04 of rdg 00to3000 30 pA9 1mQ 3mQ 10 010 0 3 mO 0 001 ofrdg C 6mo 0 04 of rdg 00to1kO 10 pA 10 mQ 10 mQ 0 10 1mQ 0 001 of rdg C 20 mQ 0 04 of rdg 00to3kO 3 pA 10 mQ 30 mQ 0 10 3 mO 0 001 of rdg C 60 mQ 0 04 of rdg 0Qto10kQ 1 pA 100 mQ 100 mQ 1 0 Q 0 04 10 mQ 0O 001960frdg C 200 mQ ofrdg 0Qto30kQ 300 nA 100 mQ 300 mQ 2 0 OQ 0 04 30 mO 0 001 of rdg C 600 mQ of rdg 0Qto100kQ 100 nA 10 10 10 0 O 0 04 100 mQ 0 001 of rdg C 20 of rdg 00 to 300kO 30 nA 10 30 300 0 04 300 mQ 0 001 of rdg C 60 of rdg NTC RTD Negative 00to100 100 pA9 0 1mQ 1mQ 0 010 0 04 0 1 mQ 0 001 of rdg C 2 mQ 1mV ofrdg 00to300 30 pA 0 1mQ 3mQ 0 01 Q 0 04 0 3 mQ 0 001 of rdg C 6 mQ of rdg 00to1000 10 pA 1mQ 10 mQ 0 1 Q 0 04 1 mO 0 001 of rdg C 20 mQ of rdg 00to3000 3pA 1mQ 30mQ X0 1 Q 40 04 3 mO 0 00196 of rdg C 60 mQ ofrdg OQtolkQ 1 pA 10 mQ 100 mQ 1 0 Q 0 04 10 mQ 0 001 ofrdg C 200 mQ ofrdg 0Qto3kQ 300 nA 10 mQ 300 mQ 2 0 Q 0 04 30mQ 0 001 ofrdg C 600 mQ ofrdg 0Qto10kQ 100 nA 100 mQ 10 10 0 Q 0 04 100 mQ 0 001 of rdg C 20 of rdg 00 to 30kO 30 nA 100 mQ 30 300 0 04 300 mO 0 001 of rdg C teo of rdg 00 to 100 KQ 10 nA 10 100 100 Q 4
69. reduce accu racy Be sure to account for errors induced by both the sensor and the instrumenta tion when computing accuracy The instrument has measurement error in reading the sensor signal and error in calculating a temperature using a temperature response curve Error results when the sensor is compared to a calibration standard and the temperature response of a sensor will shift with time and with repeated 2 8 5 Sensor Package 2 9 Sensor Calibrations 2 9 1 Precision Calibration 2 8 5 SensorPackage 29 thermal cycling from very cold temperatures to room temperature Instrument and sensor manufacturers specify these errors but there are things you can do to main tain good accuracy For example choose a sensorthat has good sensitivity in the most critical temperature range as sensitivity can minimize the effect of most error sources Install the sensor properly following guidelines in section 2 10 Calibrate the sensorand instrument periodically or in some other way null the time dependent errors Use a sensor calibration that is appropriate for the accuracy requirement There are different packages for the various types of sensors Some types of sensors can even be purchased as bare chips without any package A sensor package generally determines its size thermal and electrical contact to the outside and sometimes lim its temperature range When different packages are available for a sensor you should consider the mounting su
70. repeated at several temperatures Lake Shore www lakeshore com CRYOTRONICS 34 CHAPTER 2 Cooling System Design and Temperature Control 2 11 Heater Selection and Installation 2 11 1Heater Resistance and Power Model 350 Temperature Controller Not everyone uses the lowest excitation range available This is due to noise or more appropriately signal to noise Noise from a variety of sources affects the small signals used to make resistance measurements Lowering excitation makes the signals even smaller but unfortunately doesn t decrease the noise Even with careful installation noise effects cannot be eliminated The goal of most low temperature measurements is to choose an excitation that is the best compromise between self heating and sig nal to noise There is a variety of resistive heaters that can be used asthe controlled heating source fortemperature control The mostly metal alloys like nichrome are usually wire orfoil Shapes and sizes vary to permit installation into different systems Cryogenic cooling systems have a wide range of cooling power The resistive heater must be able to provide sufficient heating powerto warm the system 2 11 1 1 Main Heater Warmup Output 1 The Model 350 can provide up to 75 W of power from Output 1 Output 1 is designed to provide large amounts of heat for controlling at higher temperatures or for war mup TABLE 2 3 provides the current and voltage limits for Output 1 as well asthe
71. resulting maximum power for Output 1 for the 25 Q and 50 Q settings using nominal heater load values 250 setting 25 O heater 50 0 setting 50 Q heater Current limit 1 732A 1A Output 1 Voltage limit 50V 50V Max power 75W 50W TABLE 2 3 Output 1 current and voltage limits with resulting max power 2 11 1 2 Sample Heater Output 2 The Model 350 can provide up to 1 W of power from Output 2 Output 2 is designed to provide small amounts of heat for fine control of a sample stage at very low tempera tures Current limit 100 mA Output 2 Voltage limit 10V Max power 1w TABLE 2 4 Output 2 current and voltage limits with resulting max power 2 11 1 3 Calculating Power Limits Even though the Model 350 heater outputs are current sources they are limited in voltage by the voltage compliance limit This compliance voltage also limits maxi mum power So for heater values other than 25 Q or 50 Q and for values other than 100 Q on Output 2 calculate the maximum power using the following equations P I2R and P V2 R where P is maximum power is max current V is max voltage and R isthe heater resistance The current and voltage limits are in place at the same time so the smaller of the two computations gives the maximum power available to the heater 2 11 2 Heater Location 2 11 3 Heater Types 2 11 2 HeaterLocation 35 Example 1 A 20 Q heater is connected to Output 1 and the heater resistance
72. setting is setto 25 O which can provide up to 2 A of current and up to 50 V Current Limit Voltage Limit P PR P V2 R P 1 732 A 2x 200 P 50V 2 20Q P 60W P 125W The power limit is the smaller of the two or 60 W limited by current Example 2 A 120 Q heater is connected to Output 2 which is designed to provide maximum power of 1 W at 100 O by sourcing 100 mA of current Current Limit Voltage Limit P PR P V2 R P 0 1 A x 120 Q P 10 V 2 120 Q P 1 2W P 0 83 W The power limit is the smaller of the two or 0 83 W limited by voltage It is possible to choose a heater value that results in a maximum power greater than the power rating of 75 W for output 1 but doing so can cause the Model 350 to work improp erly In this situation the max user current setting should be used to limit the power Refer to section 4 5 1 1 1 for details on using the max user current setting The resistor chosen as a heater must be able to withstand the power being dissipated in it Pre packaged resistors have a power specification that is usually given for the resistor in free air This power may need to be derated if used in a vacuum where con vection cooling cannot take place and itis not adequately anchored to a cooled sur face The Model 350 has a current limit feature which allows you to specify the maximum output current for Output 1 section 4 5 1 1 which when set appropri ately will help protect the heater from being over heated
73. simplify thermal anchoring Thermal black body radiation is one ofthe ways heat is transferred Warm surfaces radiate heat to cold surfaces even through a vacuum The difference in temperature between the surfaces is one thing that determines how much heat is transferred Thermal radiation causes thermal gradients and reduces measurement accuracy Many cooling systems include a radiation shield The purpose ofthe shield is to sur round the sample stage sample and sensor with a surface that is ator neartheirtem perature to minimize radiation The shield is exposed to the room temperature surface ofthe vacuum shroud on its outer surface so some cooling power must be directed to the shield to keep it near the load temperature If the cooling system does not include an integrated radiation shield or one cannot be easily made one alternative is to wrap several layers of super insulation aluminized mylar loosely between the vacuum shroud and load This reduces radiation transfer to the sample space Even after leads are properly heat sunk and noise is effectively shielded there can bea temperature error in resistance measurements that comes from within Self heating will occur when the power from excitation current is large enough to warm the resis tor above the temperature of its surroundings The effect is most noticeable at low temperatures because the thermal conduction becomes very poor The self heating error can be determined by either c
74. sound when the alarm activates The two relays on the Model 350 can also be tied to alarm functions as described in section 5 7 2 You may want to set the Visible parameter to Off if there is no need for showing the alarm state on the front panel for instance if you are using the alarm function to trig gera relay The Audible parameter can be set to Off as well to keep the audible alarm from sounding when an alarm istriggered Menu Navigation Alarm lnput A B C D Visible Off On Alarm Input A B C D gt Audible Off On Default Visible On Audible gt On Interface Command ALARM 5 7 1 2 Alarm Latching m Latching Alarms often used to detect faults in a system or experiment that requires operator intervention The alarm state remains visible to the operator for diagnostics even if the alarm condition is removed Relays often signal remote monitors or for added safety take critical equipment off line You can cleara latched alarm by pressing Alarm and selecting Yes to the Reset Alarm prompt Select No to the Reset Alarm prompt to enter the Alarm Setup menu m Non Latching Alarms often tied to relay operation to control part of a system or experiment The alarm state follows the reading value The dead band parameter can prevent relays from turning on and off repeatedly when the sensor input reading is near an alarm setpoint 5 7 1 Alarms 93 FIGURE 5 5 illustrates the interaction between alarm setpoint and dead band
75. uses the lowest excitation range available This is due to noise or more appropriately signal to noise Noise from a variety of sources affects the small signals used to make measurements Lowering excitation makes the signals even smaller but unfortunately doesn t decrease the noise Even with careful installation noise effects cannot be eliminated The goal of most low temperature measurements is to choose an excitation that is the best compromise between self heating and signal to noise 2 7 3 Considerations When Measuring Ultra Low Temperatures Below 300 mK 2 7 3 Considerations When Measuring Ultra Low Temperatures Below 300 mK 25 Temperature measurement becomes more difficult as temperatures approach the bottom ofthe Model 350 s measurement range When measuring temperatures down to about 300 mK the 1 mV autorange setting usually results in excellent per formance At even lower temperatures you may have to manually select a current rangeto minimize measurement errors Measurementerrors come from self heating instrument resolution noise instrument uncertainty and sensor calibration uncertainty When measuring a sensor a user should choose the highest excitation current possi ble without causing significant self heating in the sensor Higher current results in the largest signal which creates the best signal to noise ratio and gives the highest instrument accuracy As the temperature approaches 100 mK self heating via I2 R Joule
76. vs kelvin for 4100 mV 0 0001 mV thermocouple sensors TABLE 5 3 Curve header parameter m Setpoint Limit limits the control setpoint to values less than or equal to this set ting A setpoint limit can be included with every curve Default is 375 K Enter a setting of 9999 K if no limit is needed m Temperature Coefficient the temperature coefficient is derived by the Model 350 from the first two breakpoints The user does not enter this setting If it is not cor rect check for proper entry ofthe first two breakpoints A positive coefficient indicates that the sensor signal increases with increasing temperature A negative coefficient indicates that the sensor signal decreases with increasing temperature Temperature response data of a calibrated sensor must be reduced to a table of breakpoints before entering it into the instrument A curve consists of 2 to 200 break points and each breakpoint consists of one value in sensor units and one temperature value in kelvin The Model 350 uses linear interpolation to calculate temperature between breakpoints The instrument will show T OVER or UNDER on the display if the sensor reading is outside the range of the breakpoints Sensor units are defined by the format setting in TABLE 5 3 Breakpoint setting resolution is six digits in temperature Most temperature values are entered with 0 001 resolution Temperature values of 1000 K and greater can be entered to 0 01 resolution Tempera
77. when a sensor reading is in the over load condition m Alarming ALARM Bit 0 this bit is set when an input is in an alarming state and the Alarm Visible parameter is on 6 2 6 Status System Detail Status Byte Register and Service Request 6 2 6 Status System Detail Status Byte Register and Service Request 113 Operation i27 6 5 4 3 2 1 0 Bit condition register 128 64 32 16 8 4 2 1 Decimal OPST e n bor jsp nafs name poy Y v v d Operation i2 6 5 4 3 2 1 0 Bit eventregister 128 64 32 16 8 4 2 1 becima OPSTR ATUNE NRDG RAMP1 RAMP2 OVLD ALARM OPSTR reads and clears the register To operation event summary Operationevent LZ 6151413 212 0 bit OSB of enable register 128 64 32 16 18 4 2 1 Decimal Qe FIGURE 6 3 Operation event register As shown in FIGURE 6 1 the Status Byte Register receives the summary bits from the two status register sets and the message available summary bit from the output buffer The status byte is used to generate a service request SRQ The selection of summary bits that will generate an SRQ is controlled by the Service Request Enable Register 6 2 6 1 Status Byte Register The summary messages from the event registers and output buffer set or clearthe summary bits of the Status Byte Register FIGURE 6 4 These summary bits are not latched Clearing an event register will clear the corresponding summary bit i
78. when sending strings otherwise characters such as spaces and other non alpha numeric characters will be interpreted as a delimiter and the full string will not be accepted It is not recommended to use commas or semi colons in sensor input names as these characters are used as delimiters for query responses Sensor Input Name Query INNAME input term a input Specifies input to query A D D1 D5 for 3062 option name term s 15 referto command for description Interface Select Command INTSEL interface term n interface Specifies the remote interface to enable O USB 1 Ethernet 2 IEEE 488 The Ethernet interface will attempt to configure itself based on the current configu ration parameters which can be set using the NET command Configuring the Ether net interface parameters prior to enabling the interface is recommended Interface Select Query INTSEL term lt interface gt term n refer to command for description Lake Shore www lakeshore com CRYOTRONICS 148 CHAPTER 6 Computer Interface Operation INTYPE Input Type Parameter Command Input INTYPE lt input gt lt sensor type gt lt autorange gt lt range gt lt compensa tion gt lt units gt lt sensor excitation gt term Format a n n n n n lt input gt Specifies input to configure A D D1 D5 for 3062 option lt sensortype gt Specifies input sensor type 0 Disabled 1 Diode 3062 option only 2
79. www lakeshore com 2 Once the firmware files have been downloaded connect to the embedded web site section 6 4 4 and navigate to the Utilities page 3 Click Launch Ethernet Firmware Updater 4 Acceptany security warning messages that are presented referto section 6 5 for an explanation of these security warnings The Ethernet Firmware Updater application window should now be open Click Upload New Ethernet Firmware and a file browser window will open 6 Navigate to the directory where the Model 350 Ethernet firmware is stored Selectthe file and click Open ot At this point the application should check to see if the firmware you are attempting to update to is newer than what is already installed on the Model 350 If it is then the firmware should immediately begin uploading and the progress of the firmware update operation should be displayed using the two progress bars in the application window Lake Shore www lakeshore com CRYOTRONICS 132 CHAPTER 6 Computer Interface Operation 6 5 3 Instrument Configuration Backup Utility Model 350 Temperature Controller The instrument configuration backup utility provides the meansto exportthe current configuration ofthe Model 350 to a file orto import a saved configuration from a file to the Model 350 The utility is useful in situations where the instrument is shared with users who require different configurations or when the instrument is often moved between syste
80. 0 04 10 0 00156 of rdg C 200 of rdg Diode Negative OVto2 5V 10 pA 0 05 8 100 pV 10 pV 80 uV 0 005 10 uV 0 0005 ofrdg C 20 pV of rdg Negative OVto10V 10 pA 0 05 8 100 pV 20 pV 320 uV 0 01 20 pV 0 0005 of rdg C 40 uV of rdg Thermocouple Positive 50 mV NA 0 1 uV 0 4uV 1 pV 40 05 0 1 pV 0 001 of rdg C 0 8yV of rdgi0 Capacitance Positive or 0 1 to 15 nf 3 496 kHz 0 1 pF 0 2 pF 30 pF 0 1 of 2 5 pF C 0 4 pF Negative 1mA square wave rdg 1to150nF 3 496 kHz 1pF 2 pF 300 pF 0 1 of 5 pF C 4 pF 10 mA square wave rdg 6 Measurement resolution of the electronics only not includingthermal noise of the resistor Control stability of the electronics only in ideal thermal system 8 Current source error has negligible effect on measurement accuracy Current source error is removed during calibration 1 Accuracy specification does not include errors from room temperature compensation 11 Option card required TABLE 1 3 Input specifications Lake Shore www lakeshore com CRYOTRONICS 8 CHAPTER 1 Introduction 1 6 2 Sensor Input Configuration 1 6 3 Thermometry Model 350 Temperature Controller RTD Diode Thermocouple Capacitance option option opt Measure B Adeadgit lead differential a ead differential 4 lead differential room temperature menttype ferential variable duty cycle compensated Constant current with 10 pA Constant current Excitation AE con
81. 0 Temperature Controller Once the total uncertainty is calculated the noise or instrument measurement reso lution can be factored in The instrument noise is calculated using the measurement resolution listed in TABLE 1 3 The temperature equivalent noise is calculated by dividing the measurement resolution by the sensor s sensitivity at the temperature of interest For a typical CX 1010 at 100 mK the measurement resolution from TABLE 1 3 is listed at 10 Q This results in 18 uK of noise 10 Q 558 110 Q K 18 pK Knowing the noise and uncertainties ofthe sensors at different excitations can help in the selection and design of the overall measurement Note that in TABLE 2 1 the self heating is only a rough estimate as the thermal resis tance electrical resistance and sensitivity are all strong nonlinear functions of tem perature and will change rapidly as you self heat away from the zero power resistance Conversely self heating is a reproducible error so if self heating can be accurately calculated or measured the self heating offset can be calibrated out The optimum excitation is a balance between minimizing self heating errors low excitation and maximizing resolution and accuracy large excitation TABLE 2 1 illustrates the tradeoffs that need to be made when selecting a sensor and excitation current Lowering excitation current can dramatically decrease the error due to self heating but sometimes reducing the current can act
82. 0 pW 1mA 300 30 pW 300 pA 100 Q 100 pW 100 pA PTC RTD Platinum n a 300 Q 300 pW 30 pA 1kQ 1mW 10 pA 3kQ 3mW 3yA 10kO 10 mW 1pA 100 10 pW 1mA 300 2 7 uW 300 pA 1000 1yW 100 pA 3000 270 nW 30 pA 1kQ 100 nW 10 pA 10 mV 3 kQ 27 nW 3 pA 10 kQ 10 nW 1 pA 30 kQ 2 7 nW 300 nA NTC RTD Cernox 100 kQ 1nw 100 nA 300 KQ 270 fW 30nA 100 100 nW 100 pA 300 27 nw 30 pA 1000 10nW 10 pA 1mV 3000 2 nW 3 pA 1kQ 1nW 1pA 3 kQ 270 fW 300 nA TABLE 4 8 Range and sensor power To keep power low and avoid sensor self heating the sensor excitation is kept low There are two major problems that occur when measuring the resulting small DC voltages The first is external noise entering the measurement through the sensor leads which is discussed with sensor setup The second is the presence of thermal EMF voltages or thermocouple voltages in the lead wiring Thermal EMF voltages appear when there is a temperature gradient across a piece of voltage lead Thermal EMF voltages must exist because the sensor is almost never the same temperature as the instrument To minimize them use careful wiring make sure the voltage leads are symmetrical in the type of metal used and how they are joined and keep unnecessary heat sources away from the leads Even in a well designed system thermal EMF volt ages can be an appreciable part of a low voltage sensor measurement The Model 350 can help with a thermal compensation algorithm The instrument will au
83. 0 temperature controller BH 1Model350instrument 1 Model 350 user s manual 4 sensor input mating connector 6 pin DIN G 106 233 2 heater output connectors dual banana for heater Outputs 1 and 2 1terminal block mating connector 10 pin terminal block for Outputs 3 and 4 and relays 1 and 2 1 line power cord m line power cord for alternative voltage Included only when purchased with VAC 120 ALL power option This section provides a description of the Model 350 rear panel connections The rear panel consists of the Input A B C and D sensor input connectors 1 in FIGURE 3 1 Output 3 and 4 analog voltage output and relays 1 and 2 terminal block connector 2 RJ 45 ethernet connector 3 USB B type connector 4 IEEE 488 interface con nector 5 line input assembly 6 Output 1 and 2 heater output connectors 7 and 8 and the thermocouple option card inputs 9 Refer to section 8 10 for rear panel con nector pin out details Lake Shore www lakeshore com CRYOTRONICS 46 CHAPTER 3 Installation Always turn off the instrument before making any rear panel connections This is espe Qo CAUTION cially critical when making sensor to instrument connections CE Be A A BEEN LakeSnore Won ETHERNET 3500005 FIGURE 3 1 Model 350 rear panel 3 4 Line Input This section describes how to properly connect the Model 350 to line power Please Assembly follow these instructions carefully to ensure proper operation
84. 1 and the output stays on until the control inputtemperature reaches the control setpoint The output will then be turned off O V and the Heater Range setting will automatically be set to Off effectively turning off all temperature control for the control loop If the Heater Range is again manually set to On the cycle will begin again and the output will turn on and stay on until the control input temperature reaches the setpoint again Menu Navigation Output Setup Output 3 or 4 Warmup Mode Auto Off m Continuous this mode implements what is often referred to as On Off control Once the Heater Range is setto on the Warm Up Percentage voltage is applied to the output until the control input temperature reaches the setpoint Then the output will turn off O V until the temperature falls 1 K below the setpoint at which point the the Warm Up Percentage voltage is again applied to the output The Heater Range will never be automatically set to Off in this mode Menu Navigation Output Setup Output 3 or 4 Warm Up Control Auto Off Continuous Default Continuous Interface Command WARMUP In Monitor Out mode the unpowered analog output 3 or 4 will track the assigned control input according to the scaling parameters you enter A common use for this function would be to send a voltage proportional to temperature to a data acquisition system The Control Input parameter setting determines which sensor input is tracked by the ou
85. 10 V 1000 K Interface Command ANALOG Lake Shore www lakeshore com CRYOTRONICS 92 CHAPTER 5 Advanced Operation 5 7 Alarms and Relays 5 7 1 Alarms Model 350 Temperature Controller Each input of the Model 350 has high and low alarm capability Input reading data from any source can be compared to the alarm setpoint values A reading higher than the high alarm setpoint triggers the high alarm for that input A reading lower than the low alarm setpoint triggers the low alarm for that input Menu Navigation Alarm Input A B C D Alarm Off On Alarm lnput A B C D Low Setpoint see note below Alarm lnput A B C D High Setpoint see note below Low and High Setpoint limits are determined by the Preferred Units ofthe associated sen sor input Defaults Alarm Off Low Setpoint 0 0000 K High Setpoint 231000 K Interface Command ALARM 5 7 1 1 Alarm Annunciators The Alarm LED annunciator steadily displays when any alarm that is enabled also has the Visible parameter enabled The annunciator flashes when any alarm that has the Visible parameter enabled activates An input need not be displayed for the system Alarm annunciator to indicate input alarm status but if the input is displayed on the front panel then the reading will alternate between the alarm status message and the actual reading If the Audible parameter is set to On for an enabled alarm then the beeper inside the instrument will
86. 10 mA 1mW 10 mw 100 mw 20 mW Range 2 3 16 mA 100 pW 1mW 10 mw 20 mW Range 1 1mA 10 pW 100 pW 1mW 5mW TABLE 3 3 Heater resistance 3 6 2 Heater Output Dual banana jacks on the rear panel ofthe instrument are used for connecting wires Connectors to the heater outputs Two standard dual banana plug mating connectors are included in the connector kit shipped with the instrument This isa common jack and additional mating connectors can be purchased from local electronic suppliers or from Lake Shore as P N 106 009 The heater is connected between the HI and LO terminals OUTPUT 1 HEATER GND OUTPUT 2 HEATER HI LO HI LO 75 W MAX 1 WMAX FIGURE 3 9 Rear panel showing heater output connectors Lake Shore www lakeshore com CRYOTRONICS 54 CHAPTER 3 Installation 3 6 3 Heater Output Wiring 3 6 4 Heater Output Noise 3 6 5 Powering Outputs 3 and 4 Using an External Power Supply CAUTION Model 350 Temperature Controller Heater output current is what determines the size gauge of wire needed to connect the heater The maximum current that can be sourced from heater Output 1 is 1 732 A When less current is needed to power a cooling system it can be limited with range settings When setting up a temperature control system the lead wire for the heater must be capable of carrying a continuous current that is greater than the maximum current Wire manufacturers recommend 26 AWG or larger wire to carry 1 732 A of current
87. 2 Scrollto the desired curve and press Enter again to view the curve header infor mation 3 Toview the curve breakpoints highlight the Curve Points parameter and press Enter The list of breakpoint pairs is scrollable but data cannot be edited 4 PressEscape Exit Menu to return to the curve header parameter list 5 Press Escape Exit Menu again to exit the Curve Entry menu and return to nor mal operation Menu Navigation Curve Entry View Curve Interface Command CRVHDR CRVPT You can erase user curves that are no longer needed Erase Curve sets all identifica tion parameters to default and blanks all breakpoint values To perform the Erase Curve operation follow this procedure 1 Press Curve Entry scroll to Erase Curve then press Enter 2 Scroll to the desired curve and press Enter 3 Choose Yes at the confirmation message to finalize the operation 4 Tocancel the operation either choose No to the confirmation message or press Escape Menu Navigation Curve Entry Erase Curve 21 59 Interface Command CRDEL Temperature curves can be copied from one location inside the Model 350 to another This is a good way to make small changes to an existing curve Curve copy may also be necessary if you need the same curve with two different temperature limits or if you need to extend the range of a standard curve The curve that is copied from is always preserved The copy routine allows you to overwrite an existing
88. 2 12 3 Good thermal conductivity is important in any part of a cryogenic system that is intended to be at the same temperature Most systems begin with materials that have good conductivity themselves but as sensors heaters sample holders etc are added to an ever more crowded space the junctions between parts are often over looked In order for control to work well junctions between the elements ofthe con trol loop must be in close thermal contact and have good thermal conductivity Gasket materials should always be used along with reasonable pressure section 2 10 4 and section 2 10 5 Poor thermal conductivity causes thermal gradients that reduce accuracy and also cause thermal lag that make it difficult for controllers to do their job Thermal lag is the time ittakes for a change in heating or cooling powerto propagate through the load and getto the feedback sensor Because the feedback sensor is the only thing that lets the controller know what is happening in the system slow information to the sensor slows the response time For example if the temperature at the load drops slightly below the setpoint the controller gradually increases heating power If the feedback information is slow the controller puts too much heat into the system before it is told to reduce heat The excess heat causes a temperature overshoot which degrades control stability The best way to improve thermal lag is to pay close attention to thermal conductivity
89. 4 3 6 5 Powering Outputs 3 and 4 Using an External Power Supply 54 3 6 5 1 Choosing a Power Supply seeressrsrrerierir tarti teeta een e eect enna 54 3 6 5 2 PowerSupplySetup sssssssssss 55 3 6 5 3 Connecting to the Model 350 ssssessssssssssssee 55 3 6 5 4 Programming Voltages Under 10V cc cece eee eee eee e eens 56 Al General m r 57 4 1 1 Understanding Menu Navigation ccs 57 4 2 Front Panel Description sssssssssssssssss I ses 58 4 2 1 Keypad Definitions cece cece eee nee nemen 58 4 2 1 1 Direct Operation Keys sssssssssssss eee teen eee i naai 58 4 2 1 2 Menu Number Pad Keys 0cceeeeee tenet eeee ee 59 4 2 2 ANNUNGIALONS a iussis pe reet Phe ev RR edu cnts aad cannes SE LO eR KR ES 59 4 2 3 General Keypad Operation sssssssssssssss eect eee eee eeeeeeees 60 4 3 Display Setup ics temer ete R3 RE RR x RR ER ER eR RR RE EE ERE RRE 61 4 3 1 Display MOdes iiis creer exa emer ei er nE ver so etc ek e eot CER Re ce 61 4 3 1 1 FourLoop Mode iisssssssssssssssssssss ees 61 4 3 1 2 AllInputs Mode issssssssssssssssssssee ens 61 4 3 1 3 Input Display Modes 00 ccc ec eee eee eee eee e eect ee eee eens 62 4 3 1 4 Custom Display Mode ssssssssssss e teste enneeeeeees 63 4 3 2 Display Contrast 2 0 eee cece een ee eee 65 4 4 Input Setup a iussocuece reve Rettore Cerne ChEUrm E a
90. 4 Press this key to enter numeric data This includes a key to toggle plus orminus anda 4 2 3 c key for entry of a decimal point TABLE 4 3 Menu number pad keys 4 2 2 Annunciators LED annunciators three blue four red LED annunciators are included to provide visual Remote feedback ofthe following operation On steady when the instrument is in Remote mode may be controlled via the IEEE 488 Interface If the LED is not illuminated the instrument is in Local mode Refer to section 4 6 3 1 Ethernet On steady when Ethernet is connected and properly configured Blinks at a slow pace when attempting to acquire an IP address Blinks rapidly when in an error state 4 6 2 Alarm On steady when the alarm feature for any sensor input is turned on and the input s Visual parame teris setto On Blinks when any input sensor alarms are in the alarming state and the alarming input s Visual parameter is setto On 5 7 Control outputs On steady when the corresponding output is in the On state does not apply to Monitor Out mode Off when corresponding output is in the Off state or when it is set to Monitor Out mode 4 5 1 4 TABLE 4 4 LED annunciators Lake Shore www lakeshore com CRYOTRONICS 60 CHAPTER 4 Operation Display annunciators include symbols for sensor inputs and their respective tempera tures and units A Sensor input A
91. 4 RTD inputs and 4 control outputs TABLE 7 1 Model description Power configurations the instrument is configured atthe factory for customer selected power as follows 100 V US NEMA 5 15 120 V US NEMA 5 15 220 V EU CEE 717 240 V EU CEE 717 240 V UK BS 1363 240 V Swiss SEV 1011 NO Uc PWN HB 220 V China GB 1002 Options TABLE 7 2 Power configurations The Model 350 includes an expansion port for various inputoption cards that provide additional sensor reading capabilities Currently the following input option cards are available Description of Options 3060 Dual thermocouple input option card Adds 2 thermocouple inputs to the Model 350 3061 Capacitance input option card Adds one capacitive sensor input to the Model 350 3062 Diode RTD expansion input option card Adds 4 scanned diode RTD inputs to the Model 350 TABLE 7 3 Model description Accessories are devices that perform a secondary duty as an aid or refinement to the primary unit Refer to the Lake Shore Temperature Measurement and Control Catalog for details A list of accessories available for the Model 350 is as follows Description of Accessories 106 009 1 Heater Output Connector Dual banana jack for heater output G 106 233 Sensor Input Mating Connector 6 pin DIN plug 4 included G 106 755 1 Terminal Block Mating Connector 10 pin terminal blockfor relays and Outputs 3 an
92. 5 2 Analog OUtputs ee oett re Y p TER ARR ERATES EAR ER UI A ELA EGG 83 4 5 2 1 Warm Up Supply sssssssssssss meme 83 4 5 2 2 MORITtOCOULE recorram r EG ER EDEN YER E S 83 NTE ACE ise tes v exe pater XEM Disbersermesduus ient et 83 4 6 1 USB ERE Eaa HEN Dede ers beak nre DOR P TOTIS 84 4 6 2 ELlBED GE svaceheneyecsge nti aicthiaiuhentanast gene ttdeer eta d E RI bre 84 4 6 3 IEEE 488 Lese ett ARARE REOR EPEENERRROUDUC EN ELI LC TR FRERQDILSS 84 4 6 3 1 Rerfiote loc l 0 ree aces an eto EE ear quera Ra Ie TUER ORA 84 Locking and Unlocking the Keypad ccc cece cece eee eee eee nn teen eee nnneas 84 General cxt aL LC MEI EL Eu 85 pede cM 85 veras PM 87 Bipolar Cohtrol 222 eese dee odes e Pe etbesteutui ates ead aliu de idea gn 89 Warm Up Supply 0 ccc cece cece cece cere II emen e nes 89 5 9 1 Warm Up Percentage eese yr teret EL coats REDE nes EEEE 89 5 5 2 Warm UP Control catorce rre e rade EATE RAE 90 Chapter 6 Computer Interface Operation 5 6 Monitor OU cocci dup 3e qd NA YA YER OE ER indeed EDUEVRIER E Y YT qd 90 5 6 1 MONOT nlts seccieisnnerece sea rh EL IRE RIA PU RE EU E EEbLen Rega 90 5 6 1 1 Polarity and Monitor Out Scaling Parameters ssss 91 5 7 Alarms and Relays cius rete resp m e CER EU ER A TRE e Pte 92 SAT AlANMS 28d 2 T E EEE ATE E A TAA EEAS E ESEA 92 5 7 11 Alarm Annunciators cerco ttt rane e ete aa na AEE 92 5 7 1 2 Alarm Latching iiis esee reote Ioco De e
93. 760 curve SoftCal Point One SoftCal Point Two SoftCal Point Three Liquid nitrogen Room temperature High temperature boiling point point point 77 35K 305K 480K f E ae ee I 0 50 100 150 200 250 300 350 400 450 500 550 600 650 50 100 K 200 325 K 400 600 K FIGURE 5 9 Acceptable temperature range for platinum SoftCal sensors One two or three calibration data points can be used If you are using one point the algorithm shifts the entire curve up or down to meet the single point If you are using two points the algorithm has enough information to tilt the curve achieving good accuracy between the data points The third point extends the improved accuracy to span all three points m Point 1 calibration data point at or near the boiling point of nitrogen 77 35 K Acceptable temperature entries are 50 K to 100 K m Point 2 calibration data point near room temperature 305 K Acceptable tem perature entries are 200 K to 300 K m Point 3 calibration data point at a higher temperature 480 K Acceptable tem perature entries are 400 K to 600 K A SoftCal calibration is only as good as the accuracy of the calibration points The accuracies listed for SoftCal assume 0 05 K for 77 35 K liquid nitrogen and 305 K room temperature points If you are performing the SoftCal with Lake Shore instruments note that the boiling point of liquid cryogen though accurate is affected by atmospheric pressure Use calibrated s
94. 8 7 Ethernet pin and connector details NEN 1 TXD4 Transmit data 2 TXD Transmit data 3 RXD Receive data 4 EPWR Power from switch not used 5 EPWR Power from switch not used 6 RXD Receive data 7 EPWR Power from switch not used 8 EPWR Power from switch not used TABLE 8 6 Ethernet pin and connector details Connect to the IEEE 488 Interface connector on the Model 350 rear with cables spec ified in the IEEE 488 standard The cable has 24 conductors with an outer shield The connectors are 24 way Amphenol 57 Series or equivalent with piggyback recepta cles to allow daisy chaining in multiple device systems The connectors are secured in the receptacles by 2 captive locking screws with metric threads The total length of cable allowed in a system is 2 m for each device on the bus or 20 m maximum The Model 350 can drive a bus of up to 10 devices A connector extender is required to use the IEEE 488 interface and relay terminal block at the same time FIGURE 8 8 shows the IEEE 488 interface connector pin location and signal names as viewed from the Model 350 rear panel FIGURE 8 8 IEEE 488 interface 8 11 Electrostatic Discharge 8 11 1 Identification of Electrostatic Discharge Sensitive Components 8 11 ElectrostaticDischarge 173 TEENS 1 DIO 1 Data input output line 1 2 DIO2 Data input output line 2
95. A User 28W 69 5 W 83W X x X 1414A 20W 50W 60W x x x 1 25 A User 15W 39W 46W 62 5 W x X 1A 10W 25W 30W 40W 50W 0 707 A SW 12 5W 15W 20W 25W EE 0 5 A User 2 5 W 6W 7 5 W 10W 12 5W 25W Shaded black Max current too high for these resistances due to voltage compliance limit Bold Discrete options available for 25 Q and 50 Q heaters under the Max Current setting Model 350 Temperature Controller TABLE 4 14 User Max Current Menu Navigation Output Setup Output 1 User Max Current 0 1 A to 1 732 A Default User Max Current gt 1 732 A 4 5 1 2 Power Up Enable All configuration parameters ofthe Model 350 can beretained through a power cycle Some systems require that the Heater Range is turned off when power is restored The power up enable feature allows you to choose whether or not the heater range is turned off each time the instrument power is cycled Set the Power Up Enable param eter to Off to ensure that the heater range is turned off on power up Set it to On to return the Heater Range to its previous setting when power is restored Menu Navigation Output Setup Output 1 2 3 or 4 Power Up Enable Off or On Default Off Interface Command OUTMODE 4 5 1 HeaterOutputs 77 4 5 1 3 Heater Out Display The heater output can be displayed in units of percent offull scale current or percent of full scale power The heater output display on the front panel is displayed in these units an
96. CRYOTRONICS 72 CHAPTER 4 Operation During normal operation only the curves that share the inputtype you have selected are displayed If the curve you wish to select does not appear in the selection sequence make sure the curve format matches the recommended format for the input type selected Refer to TABLE 4 7 The sensor reading of the instrument can always be displayed in sensor units If a tem perature response curve is selected for an input its readings may also be displayed in temperature 01 DT 470 Diode DT 470 1 4 475K Table D 1 02 DT 670 Diode DT 670 1 4 500K Table D 2 03 DT 500 D Diode DT 500 D 1 4 365K Table D 3 04 DT 500 E1 Diode DT 500 E1 1 1 330K Table D 3 05 Reserved 06 PT 100 PTC RTD PT 100 30 800K Table D 4 07 PT 1000 PTC RTD PT 1000 30 800K Table D 4 08 RX 102A AA NTC RTD Rox RX 102A 0 05 40 K Table D 5 09 RX 202A AA NTC RTD Rox RX 202A 0 05 40 K Table D 6 10 Reserved m Reserved 12 Type K Thermocouple Type K 3 1645 K Table D 7 13 Type E Thermocouple Type E 3 1274K Table D 8 14 Type T Thermocouple Type T 3 670K Table D 9 15 AuFe 0 03 Thermocouple AuFe 0 03 3 5 500K Table D 10 16 AuFe 0 07 Thermocouple AuFe 0 07 3 15 610K Table D 11 17 Reserved 18 Reserved 19 Reserved 20 Reserved 21 59 User Curves No
97. E Input Format Returned Format Remarks KRDG Input Format Returned Format Remarks LEDS Input Format Remarks Example LEDS Input Returned Format LOCK Input Format Remarks Example LOCK Input Returned Format 6 6 1 Interface Commands 149 The lt autorange gt parameter does not apply to diode thermocouple or capacitance sensor types the lt range gt parameter does not apply to the thermocouple sensor type the lt compensation gt parameter does not apply to the diode sensor type and the lt sen sor excitation gt parameter only applies to the NTC RTD sensor type When configuring sensor inputs all parameters must be included but non applicable parameters are ignored A setting of O for each is recommended in this case Input Type Parameter Query INTYPE lt input gt term a lt input gt Specifies input to query A D D1 D5 for 3062 option lt sensor type gt lt autorange gt lt range gt lt compensation gt lt units gt lt sensor excitation gt term n n n n n refer to command for description If autorange is on the returned range parameter is the currently auto selected range Kelvin Reading Query KRDG lt input gt term a lt input gt Specifies which input to query A D D1 D5 for 3062 option lt kelvin value gt term tnnnnnn Also see the RDGST command Front Panel LEDS Command LEDS off on term n off on O LEDs Off 1 L
98. EDs On If set to O front panel LEDs will not be functional Function can be used when display brightness is a problem LED O term turns all front panel LED functionality off Front Panel LEDS Query LEDS term off on term n referto command for description Front Panel Keyboard Lock Command LOCK state code term n nnn state 0 Unlocked 1 Locked code Specifies lock out code Valid entries are 000 999 Locks out all front panel entries except pressing the All Off key to immediately turn off all heater outputs Refer to section 4 7 LOCK 1 123 term enables keypad lock and sets the code to 123 Front Panel Keyboard Lock Query LOCK term lt state gt lt code gt term n nnn refer to command for description Lake Shore www lakeshore com CRYOTRONICS 150 CHAPTER 6 Computer Interface Operation MDAT Input Format Returned Format Remarks MNMXRST Input Remarks MODE Input Format Example MODE Input Returned Format MOUT Input Format Example Remarks MOUT Input Format Returned Format NET Input Format Model 350 Temperature Controller Minimum Maximum Data Query MDAT lt input gt term a input Specifies which input to query A D D1 D5 for 3062 option lt min value gt lt max value gt term tnnnnnn tnnnnnn Returns the minimum and maximum input data Also see the RDGST command Minimum and Maximum Function Reset Com
99. ERISERISRM UPPER beep cadeeenaee Mebbbe dines 105 6 2 EEE 488 Interface ecce exe ca ette e CELER n a s E REOR E Ing 105 6 2 1 Changing IEEE 488 Interface Parameters sss 106 6 2 2 Remote Local Operation isssssssssssssssssss eee 106 6 2 3 IEEE 488 2 Command Structure 0 cece cece e teen ees 106 6 2 3 1 Bus Control Commands sss 106 6 2 3 2 Common Commands sss een 107 6 2 3 3 Device Specific Commands ssssssssssssss 107 6 2 3 4 Message Strings iiu aoi ERR EEDAER E EN RUE EEERENDUERT FER 107 6 2 4 Status System Overview sssssssssssss e emen 108 6 2 4 1 Condition Registers 0 0 cece cece eee eect ee krian RAER ene 108 6 2 4 2 EVerIERegISEGIS dr eva dd ex cape ah bee ex eR Erbe RP RR ERE Eee 108 6 2 4 3 Enable Registers ccc ce eesest rese hence ree ree hr eed ed SEEN 108 6 2 4 4 Status Byte Register siucsoise steterit ee Ra epe Pe a EORR 110 6 2 4 5 Service Request Enable Register esses 110 6 2 4 6 Reading Registers isses eene 110 6 2 4 7 Programming Registers cssssssssss n 110 6 2 4 8 Clearing Registers aisaiviva saves d EE RIS EY ERR S RT RTE RA GRON 111 6 2 5 Status System Detail Status Register Sets 111 6 2 5 1 Standard Event Status Register Set sssssssssssssssss 111 6 2 5 2 Operation Event Register Set c sss 112 6 2 6 Status System Detail Status Byte Register and Service Request 113 6 2 6 1 Status B
100. ID Input Format Returned Format RAMP Input Format Example Remarks RAMP Input Format Returned Format RAMPST Input Format Returned Format 6 6 1 InterfaceCommands 153 Control Loop PID Values Command PID lt output gt lt P value gt lt I value gt lt D value term n nnnnn nnnnn nnnn lt output gt Specifies which output s control loop to configure 1 4 P value The value for output Proportional gain 0 1 to 1000 lt l value The value for output Integral reset 0 1 to 1000 D value The value for output Derivative rate O to 200 Control settings P l D and Setpoint are assigned to outputs which results in the settings being applied to any loop formed by the output and its control input PID 1 10 50 0 term Output 1 P is 10 I is 50 and Dis 0 Control Loop PID Values Query PID lt output gt term n lt output gt Specifies which output s control loop to query 1 4 P value l value gt lt D value term nnnnn tnnnnn nnnn referto command for description Control Setpoint Ramp Parameter Command RAMP output off on rate value term n n nnnn output Specifies which output s control loop to configure 1 4 off on Specifies whether ramping is O Off or 1 On rate value Specifies setpoint ramp rate in kelvin per minute from 0 1to 100 The rate is always positive but will respond to ramps up or down A rate of 0 is inte
101. IGURE 2 4 e A derivative setting of O off is recommended when the con trol system is seldom changed and data is taken when the load is at steady state The derivative setting is entered into the Model 350 as a percentage of the integral time constant The setting range is 0 200 where 100 1 4 seconds Start with a setting of 50 to 100 Again do not be afraid to make some small setpoint changes halving or doubling this setting to watch the affect Expect positive setpoint changes to react differently from negative setpoint changes Choosing appropriate PID control settings can be tedious Systems can take several minutes to complete a setpoint change making it difficult to watch the display for oscillation periods and signs of instability With the Autotune feature the Model 350 automates the tuning process by measuring system characteristics and along with some assumptions about typical cryogenic systems computes setting values for P and D Autotune works only with one control loop at a time and does not set the man ual output or heater range Setting an inappropriate heater range is potentially dan gerous to some loads so the Model 350 does not automate that step of the tuning process When Autotune is initiated step changes are applied to the setpoint and the system response is observed to determine the best tuning parameters The Autotuning message appears when autotuning and the display is configured to show the out
102. Inc of Santa Clara CA LabVIEW is a registered trademark of National Instruments Mac is a registered trademark of Apple Inc registered in the U S and other countries Microsoft Windows Excel and Windows Vista are registered trademarks of Microsoft Corporation in the United States and other countries Copyright 2012 14 Lake Shore Cryotronics Inc All rights reserved No portion of this manual may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without the express written permission of Lake Shore Lake Shore CRVOTBONICS www lakeshore com CE DECLARATION OF CONFORMITY We Lake Shore Cryotronics Inc 575 McCorkle Blvd Westerville OH 43082 USA hereby declare that the equipment specified conforms to the following Directives and Standards Application of Council Directives 2006 95 EC LVD 2004 108 EC EMC 2011 65 EU RoHS Standards to which Conformity is declared EN 61010 1 2010 Overvoltage II Pollution Degree 2 EN 61326 1 2013 Class A Annex B EN 50581 2012 Model NUMMBOF cccncces ua aerea rnnt hme rnm nn 350 E A Au lezoi At j OIN Scott Ayer Director of Quality and Compliance Position Model 350 Temperature Controller Electromagnetic Compatibility EMC for the Model 350 Temperature Controller Electromagnetic Compatibility EMC of electronic equipment is
103. K 179 mK 216 mK 32 3 mK GaAlAs Diode with 1 4H ener 300 0 8978V 2 85mV K 7mk 60 mK 95mK 14 0 mK 475 0 3778V 3 15 mV K 6 3 mK 37 mK 86 mK 12 7 mK 4 2 6 0nF 27pF K 74mK Calibrationnot 14 8 mK Capacitance Cs 501 77 9 1 nF 52 pF K 39mK NA available from 7 7 mK 200 19 2 nF 174 pF K 12 mK Lake Shore 23 mK i 75 5862 9uV 15 6uV K 26mK Ecc e 513mK E ETT SK 300 1075 3uV 40 6 pV K 9 9 mK 38 mK5 availablefomm tuo7 mi p yp 600 13325gV 4 7 V K 9 6 mK 184 mlG e 19 2 mK 1500 498134V 36 1jV K 11mK 718 mK5 22 2 mK 2 Typical sensor sensitivities were taken from representative calibrations for the sensor listed 3 Control stability of the electronics only in an ideal thermal system 4 Non HT version maximum temperature 325 K 5 Accuracy specification does not include errors from room temperature compensation TABLE 1 2 Typical sensor performance Model 350 Temperature Controller 1 6 Model 350 Specifications 1 6 1 Input Specifications Sensor Temperature Coefficient Input Range Excitation Current DIED Resolution Measurement Resolutions 1 6 Model 350Specifications Electronic Accuracy at 25 C Measurement Temperature Coefficient Electronic Stability NTC RTD Negative 00to100 1mA 0 1mQ 0 1mQ 0 002 Q 0 01 mQ 0 001 of rdg C 0 2 mQ PTC RTD Positive 0 06 of
104. Lake Shore Model 350 it might be displayed as USB Device If neitherare displayed click Action and then select Scan for hardware changes which may open the Found New Hardware wizard automatically If the Found New Hardware wizard opens continue to step 4 d Right click on Lake Shore Model 350 and click Update Driver 4 Select No notatthis time and click Next 5 Select Search for the best driver in these locations click to clear the Search removable media floppy CD ROM check box and click the Include this loca tion in the search check box 6 Click Browse and open the location of the extracted driver Click Next 8 Whenthe driver finishes installing a confirmation message stating The wizard has finished installing the software for Lake Shore Model 350 Temperature Con troller should appear Click Finish to complete the installation M 6 3 3 4 Installing the USB Driver from the Included CD The Model 350 USB driver is available on the included CD The following section describes the process of installing the driverfrom the CD To install the driver you must be logged into a user account that has administrator privileges For Windows 7 and Vista 1 Insertthe CD into the computer 2 Follow steps 1 9 ofthe Windows Vista procedure in section 6 3 3 3 3 3 Click Browse and selectthe drive containing the included CD 4 Ensure the Include subfolders check box is selected and click Next 5 Whenthe driver finishes insta
105. ODE Remote Interface Mode Cmd 150 ALARM Input Alarm Parameter Cmd 140 MODE Remote Interface Mode Query 150 ALARM Input Alarm Parameter Query 141 MOUT Manual Output Cmd 150 ALARMST Input Alarm Status Query 141 MOUT Output Manual Heater Power MHP Output Query 150 ALMRST Reset Alarm Status Cmd 141 NET Network Settings Cmd 150 ANALOG Monitor Out Parameter Cmd 141 NET Network Settings Query 151 ANALOG Monitor Out Parameter Query 142 NETID Network Configuration Query 151 AOUT Analog Output Data Query 142 OUTMODE Output Mode Command 152 ATUNE Autotune Cmd 142 OUTMODE Output Mode Query 152 BRIGT Display Contrast Cmd 142 PID Control Loop PID Values Cmd 153 BRIGT Display Contrast Query 142 PID Control Loop PID Values Query 153 CRDG Celsius Reading Query 142 RAMP Control Setpoint Ramp Parameter Cmd 153 CRVDEL Curve Delete Cmd 143 RAMP Control Setpoint Ramp Parameter Query 153 CRVHDR Curve Header Cmd 143 RAMPST Control Setpoint Ramp Status Query 153 CRVHDR Curve Header Query 143 RANGE Heater Range Cmd 154 CRVPT Curve Data Point Cmd 143 RANGE Heater Range Query 154 CRVPT Curve Data Point Query 143 RDGST Input Reading Status Query 154 DFLT Factory Defaults Cmd 144 RELAY Relay Control Parameter Cmd 154 DISPFLD Custom ModeDisplay Field Cmd 144 RELAY Relay Control Parameter Query 154 DISPFLD Custom Mode Display Field Query 144 RELAYST Relay Status Query 155 DISPLAY Display Setup Cmd 145 SCAL Generate
106. OPC ofthe Standard Event Sta tus Register If OPC is sent as the last command in a command sequence bit 0 will be set when the instrument completes the operation that was initiated by the command sequence Additional commands may be sent between the instrument and the bus controller while waiting forthe initial pending operation to complete A typical use of this function would be to enable the OPC bitto generate an SRQ and include the OPC command when programming the instrument The bus controller could then be instructed to look for an SRQ allowing additional communication with the instru ment while the initial process executes The OPC query has no interaction with bit O OPC ofthe Standard Event Status Reg ister If the OPC query is sent at the end of a command sequence the bus will be held until the instrument completes the operation that was initiated by the com mand sequence Additional commands except RST should not be sent until the operation is complete as erratic operation will occur Once the sequence is complete a1will be placed in the output buffer This function is typically used to signal a com pleted operation without monitoring the SRQ It is also used when itis important to prevent any additional communication on the bus during a pending operation Lake Shore www lakeshore com CRYOTRONICS 116 CHAPTER 6 Computer Interface Operation 6 3 USB Interface 6 3 1 Physical Connection 6 3 2 Hardware Support
107. OTRONICS 104 CHAPTER 5 Advanced Operation Model 350 Temperature Controller 6 1General 105 Chapter 6 Computer Interface 6 1 General 6 2 IEEE 488 Interface Operation This chapter provides operational instructions for the computer interface for the Lake Shore Model 350 temperature controller Each of the three computer interfaces provided with the Model 350 permit remote operation The first is the IEEE 488 interface described in section 6 2 The second is the USB interface described in section 6 3 The third isthe Ethernet interface described in section 6 4 The three interfaces share a common set of commands detailed in section 6 6 Only one ofthe interfaces can be used at a time The IEEE 488 interface is an instrumentation bus with hardware and programming standards that simplify instrument interfacing The Model 350 IEEE 488 interface complies with the IEEE 488 2 standard and incorporates its functional electrical and mechanical specifications unless otherwise specified in this manual All instruments on the interface bus perform one or more ofthe interface functions of Talker Listener or Bus Controller A Talker transmits data onto the bus to other devices A Listener receives data from other devices through the bus The Bus Control ler designates to the devices on the bus which function to perform The Model 350 performs the functions of Talker and Listener but it cannot be a Bus Controller The Bus Controller is the
108. On setting for enabling the output While controlling tempertature the following will cause the heater range to automati cally turn off m Exceeding the Temperature Limit setting m Setup changes to the control input WB Power loss with Power Up Enable feature turned off m Input errors such as T Over T Under S Over and S Under Available full scale current and power for output 1 are determined by the heater resis tance Max Current setting and Heater Range Specifications ofthe heater outputs are provided in section 1 6 Heater theory of operation is provided in section 2 4 Various heater installation considerations are provided in section 3 6 4 5 2 Analog Outputs 4 6 Interface 4 5 2 AnalogOutputs 83 To set Heater Range first configure the front panel display to show the desired control loop information then use the Heater Range key on the front panel A quick way to access the setting if the control loop information is not already being displayed is to press A B C or D on the front panel to temporarily display the control loop informa tion while the new setting is entered Refer to section 4 2 for details on configuring the front panel display Menu Navigation Heater Range Off On Range 1 Range 2 Range 3 Range 4 Range 5 Default Off Interface Command RANGE 4 5 1 5 9 ALL OFF The ALL OFF key is provided as a means of shutting down all control outputs with one key It is equivalent to setting the H
109. Output 1 2 3 or 4 Control Input None Input A Input B Input C Input D Default Output 1 Control Input Input A Output 2 Control Input Input B Output 3 4 Off Interface Command HTRSET 4 5 1 5 2 Proportional P The proportional parameter also called gain is the P part of the PID control equation It has a range of O to 1000 with a resolution of 0 1 The default value is 50 Enter a value greater than O for P when using closed loop control To set P first configure the front panel display to show the desired control loop infor mation then use the P key on the front panel A quick way to access the setting if the control loop information is not already being displayed is to press A B C or Don the front panel to temporarily display the control loop information while the new setting is entered Refer to section 4 3 for details on configuring the front panel display Menu Navigation P 0 to 9999 Default 50 Interface Command PID 4 5 1 5 3 Integral I The integral parameter also called reset is the part of the PID control equation It has a range of O to 1000 with a resolution of 0 1 The default value is 20 Setting to O turns the reset function off The I setting is related to seconds by setting 1000 lseconds For example a reset number setting of 20 corresponds to a time constant of 50 s A system will normally take several time constants to settle into the setpoint The 50 s time con
110. OutputConnectors 53 3 6 1 1 Output 1 Output 1 is a traditional control output for a cryogenic temperature controller It is a DC current source with software settable ranges and limits It is designed for high power up to 75 W providing control at higher temperatures and fast warmup capa bility Output 1 is configurable for optimization using either a 25 Q ora 50 Q heater resistance At the 50 Q setting it is limited to a maximum output current of 1A and at the 25 Q setting the maximum heater output current is 1 73 A The compliance volt age is 50V minimum but can reach as high as 58 V if the heater resistance is higher than the nominal setting Heater power is applied in one of five ranges Each range is one decade lower in power Refer to TABLE 3 3 for maximum current and power rat ings into different heater resistances 3 6 1 2 Output 2 Output 2 is also a DC current source but is designed for low power up to 1 W provid ing stable control at very low temperatures It is limited to a maximum output current of 100 mA and a compliance voltage of at least 10 V but can be as high as approxi mately 13 V Output 2 also has five ranges each one decade lower in powerthan the last Referto TABLE 3 3 for maximum current and power ratings into different heater resistances 100 1000 1000 Q 5000 Q Range 5 100 mA 100 mw 1W 100 mw 20mW Range4 31 6 mA 10 mw 100 mw 100 mw 20 mW Output range Range 3
111. Platinum RTD 3 NTCRTD 4 Thermocouple 3060 option only 5 Capacitance 3061 option only lt autorange gt Specifies autoranging 0 off and 1 on lt range gt Specifies input range when autorange is off Sensor Sensor type ae yP excitation Diode 3062 option only ng Range 0 2 5V 1 10V PTC RTD 10 mV 2 1000 3 3000 6 10kQ 0 100 1 300 4 1kO 5 3kO 10 mV or 1 mV NTC RTD 2 1000 3 3000 6 10kQ 7 30kQ 8 100kO 0 100 1 300 4 1kO 5 3kO 10 mV 9 300kQ Thermocouple na 0250mV Capacitance na 1 150nF 0 15nF TABLE 6 8 Input range lt compensation gt Specifies input compensation where 0 off and 1 on Reversal for thermal EMF compensation if input is resistive room com pensation if input is thermocouple Also used to set tempera ture coefficient for capacitance sensors where 0 negative and 1 positive Always 0 if input is a diode 3062 option only lt units gt Specifies the preferred units parameter for sensor readings and for the control setpoint 1 kelvin 2 Celsius 3 Sensor lt sensorexcitation gt Specifies the sensor excitation voltage level to maintain for the NTC RTD sensor type 0 1 mV and 1 10 mV Example INTYPE A 3 1 0 1 1 1 term sets Input A sensor type to NTC RTD autorange on thermal compensation on preferred units to kelvin and sensor excitation to 1 mV Model 350 Temperature Controller Remarks INTYP
112. Ports COM amp LPT 5 Check that the USB driver is installed properly and that the device is functioning In Microsoft Windows the device status can be checked using Device Manager by right clicking Lake Shore Model 350 Temperature Controller under Ports COM amp LPT or Other Devices and then clicking Properties 8 2 3 Intermittent 1 Check cable connections and length Lockups 2 Increase the delay between all commands to 100 ms to make sure the instru ment is not being overloaded 3 Ensure that the USB cable is not unplugged and that the Model 350 is not pow ered down while the com port is open The USB driver creates a com port when the USB connection is detected and removes the com port when the USB connec tion is no longer detected Removing the com port while in use by software can cause the software to lock up or crash Lake Shore www lakeshore com CRYOTRONICS 166 CHAPTER 8 Service 8 3 IEEE Interface Troubleshooting 8 3 1 New Installation 8 3 2 Existing Installation No Longer Working 8 3 3 Intermittent Lockups 8 4 Fuse Drawer 8 5 Line Voltage Selection AWARNING Model 350 Temperature Controller This section provides IEEE interface troubleshooting for issues that arise with new installations old installations and intermittent lockups Check the instrument address Always send a message terminator Send the entire message string at one time including the terminator Send only one simpl
113. TRONICS 6 CHAPTER 1 Introduction Temperature Accuracy Electronic Including Control Electronic Stability3 Accuracy Temperature CalCurve and Equivalents Calibrated Sensor Measurement Electronic Resolution Accuracy Temperature Temperature Equivalents Equivalents Example Nominal Typical Resistance Sensor Voltage Sensitivity2 Temperature Lake Shore K Sensor 213890 5581100 K 4 5 4K 69 uK 4 1mK 10 8 uK GEM CX 1010 SD 0 3 2322 40 10785 Q K 28 uK 272 uK 4 3 mK 55 6 uK mV with 0 1L 0 5 124820 2665 2 Q K 113 pK 938 uK 4 9 mK 225 uK calibration 4 2 277 3300 32 209 Q K 931 yK 6 5 mK 11mK 190 uK 300 30 3920 0 0654 Q K 153 mK 1 7K 18 K 306 mK IE m E nume 14 26566 Q 48449 QJK 6 2uK 261 uK 4 3 mK 12 4 uK Cernox Wilfrid 4 2 350720 1120 8 Q K 89 uK 2 1mK 6 1mK 178 UK 10 mv calibration 77 205 670 2 4116 Q K 1 2 mK 38 mK 50 mK 2 5 mK 420 45 030 0 0829 Q K 12 mK 338 mK 412 mK 24 1mK 0 1 23370 718580 K 4 2K 21uK 4 0 mK 8 3 UK 0 3 1640 964 O K 31 1 4K 130 uK 4 1 mK 62 2 uK a eae ecc 0 5 7380 20290 K 493yK 244 uK 4 2 mK 98 6 UK i 14 2470 13 15 Q K 228 uK 1 2 mK 5 2mK 456 uK 4 2 1370 1 036 Q K 2 9 mK 11 mK 15 mK 5 8mK 0 3 351800 512200 Q K 2 uK 47 uK 4 0 mK 3 9 uK Germanium GR 300 AA with 1 4 448 60 581 3 Q K 17 UK 481 uK 4 5 mK 34 4 uK 10 mv 0 3D calibra
114. The network address parameters of the Model 350 can be configured using one of three methods DHCP Auto IP or Static IP DHCP and Auto IP are automatic configu ration methods and Static IP requires manual configuration If supported by the server DHCP can also be used to automatically configure DNS server addresses as well as IP address parameters An order of precedence is followed when the Model 350 attempts to acquire IP address parameters If enabled the DHCP method will be used first If DHCP is dis abled or ifthe attempt to acquire parameters from the DHCP server fails the Model 350 then checks if Auto IP is enabled If Auto IP is enabled this method will be used If disabled or if this attempt fails the Static IP method will be used If the Static IP method fails the IP address parameters will not be configured and the Ethernet status will enter an error state Refer to section 6 4 2 1 if you receive an error message Dynamic Host Configuration Protocol DHCP DHCP is a method of automatically configur ing the IP address subnet mask and gateway of Ethernet devices on a network This method provides simple automatic configuration for users connecting to a network that provides a DHCP server The network DHCP server will provide an IP address sub net mask and gateway address Depending on the DHCP server configuration it may also provide primary DNS and secondary DNS addresses as well DHCP is the simplest method of IP config
115. User s Manual Model 350 Temperature Controller Lake Shore Cryotronics Inc sales lakeshore com 575 McCorkle Blvd service lakeshore com Fax 614 891 1392 Westerville Ohio 43082 8888 USA www lakeshore com Telephone 614 891 2243 Methods and apparatus disclosed and described herein have been developed solely on company funds of Lake Shore Cryotronics Inc No government or other contractual support or relationship whatsoever has existed which in any way affects or mitigates proprietary rights of Lake Shore Cryotronics Inc in these developments Methods and appa ratus disclosed herein may be subject to U S Patents existing or applied for Lake Shore Cryotronics Inc reserves the right to add improve modify or withdraw functions design modifications or products at any time without notice Lake Shore shall not be liable for errors contained herein or for incidental or consequential damages in connection with furnishing performance or use of this material Rev 1 3 P N 119 057 09 January 2014 Lake Shore www lakeshore com CRYOTRONICS LIMITED WARRANTY STATEMENT WARRANTY PERIOD THREE 3 YEARS 1 Lake Shore warrants that products manufactured by Lake Shore the Product will be free from defects in materials and workmanship for three years from the date of Purchaser s physical receipt of the Prod uct the Warranty Period If Lake Shore receives notice of any such defects during the Warranty Period and the defecti
116. a growing concern worldwide Emissions of and immunity to electromagnetic interference is now part of the design and manufacture of most electronics To qualify forthe CE Mark the Model 350 meets or exceeds the requirements of the European EMC Directive 89 336 EEC as a CLASS A product A Class A product is allowed to radiate more RF than a Class B product and must include the follow ing warning WARNING This is a Class A product In a domestic environment this product may cause radio interference in which case the user may be required to take adequate measures The instrument was tested under normal operating conditions with sensor and interface cables attached If the installation and operating instructions in the User s Manual are followed there should be no degradation in EMC performance This instrument is not intended for use in close proximity to RF Transmitters such as two way radios and cell phones Exposure to RF interference greater than that found in a typical laboratory environment may disturb the sensitive measurement circuitry ofthe instrument Pay special attention to instrument cabling Improperly installed cabling may defeat even the best EMC protection Forthe best performance from any precision instrument follow the grounding and shielding instructions in the User s Manual In addition the installer of the Model 350 should consider the following Shield measurement and computer interface cables Leave no unused or untermina
117. ailable when controlling in temperature units to provide smooth continuous control from one temperature to the next Refer to section 4 4 for details on Input Setup Refer to sec tion 4 5 1 5 1 for details on assigning a Control Input Refer to section 4 5 1 5 7 for details on the Setpoint Ramping feature 4 5 1 HeaterOutputs 81 Most applications require control in units of temperature To control in units of tem perature set the Preferred Units parameter of the control input sensor to either kel vin or Celsius When controlling in temperature the available setting range of the setpoint is limited by the Setpoint Limit parameter of the assigned temperature curve Referto section 4 4 12 for details on setting the Preferred Units parameter Refer to section 5 8 1 for details on setting a curve Setpoint Limit The Setpoint Limit feature only limits the Setpoint entry For even greater protection the Temperature Limit feature can be used to turn off all heater outputs if a sensor reading above the specified temperature is observed Refer to section 4 4 11 for details on the Temperature Limit feature There are some instances when temperature control in sensor units may be desired for example when a temperature curve is not available For these applications the Model 350 can control temperature in sensor units To control in sensor units set the Preferred Units parameter to Sensor When controlling in sensor units the Setpoint resolution match
118. alculating the error using the thermal resistance ofthe sensoror by lowering the excitation current until self heating does not cause change in measured resistance To calculate the self heating first determine the thermal resistance ofthe sensor and package at the desired temperature contact Lake Shore for typical thermal resis tances of common sensors Second calculate the self heating according to the equa tion ATs 4 I2R R where ATsp is the error due to self heating is the excitation current R is the electrical resistance and R is the thermal resistance To measure the effect of self heating use the current ranges available in the Model 350 Begin by cooling the resistor to the desired temperature and measure its value using the highest current excitation available for the resistor being measured Step up one resistance range dropping the current by about 2 3 and measure resis tance again A change in measured value indicates self heating was present on the higher range Continue increasing the resistance range until the change is no longer significant to the measurement If there is still a measured change at the lowest cur rent setting then a different sensor may need to be chosen A variety of sensor pack ages and typical resistances are available so a sensor with a lower typical resistance or more thermal resistance at the desired temperature may be required Thermal resistance changes with temperature so this process must be
119. alibration data point X where X can be point 1 2 or 3 If only 1 or 2 data points were acquired only enter those data points and leave the others at their default values Note the acceptable temperature ranges for each calibration data point in FIGURE 5 8 and FIGURE 5 9 If a temperature value outside of the acceptable range is entered the value will be limited to the closest acceptable value Once the data points are entered highlight Generate Softcal and press Enter Choose Yes atthe confirmation message to finalize the operation To cancel the operation either choose No to the confirmation message or press Escape When the Softcal curve has been generated the following message will appear on the display SoftCal curve has been generated The Generate Softcal operation will overwrite an existing user curve Please ensure the curve number you are writing to is correct before generating the calibrated curve You can checkthe new curve using the View Curve instructions in section 5 9 2 The curve is not automatically assigned to any input so you will need to assign itto an input Refer to section 4 4 8 for details on assigning a curve to a sensor input Menu Navigation Curve Entry gt Softcal DT 470 Platinum 100 Platinum 1000 Data Entry see note below gt Generate Softcal Yes Interface Command SCAL Data entry includes new curve serial number and calibration points Lake Shore www lakeshore com CRY
120. ameter data gt lt terminators gt Command mnemonics and parameter data necessary for each one is described in section 6 6 Terminators must be sent with every message string A query string is issued by the computer and instructs the instrument to send a response The query format is query mnemonic gt lt gt lt space gt lt parameter data gt lt terminators gt Query mnemonics are often the same as commands with the addition of a question mark Parameter data is often unnecessary when sending queries Query mnemonics and parameter data if necessary is described in section 6 6 Terminators must be sent with every message string The computer should expect a response very soon after a query is sent Aresponse string is the instrument s response or answerto a query string The response can be a reading value status report or the present value of a parameter Response data formats are listed along with the associated queries in section 6 6 The response is sent as soon as possible after the instrument receives the query Itis important to rememberthat the user program is in charge ofthe USB communi cation at all times The instrument cannot initiate communication determine which device should be transmitting at a given time or guarantee timing between mes sages All of this is the responsibility of the user program When issuing commands the user program alone should m Properly format and transmit the command including the termin
121. amically adjusts the current source output operation point to minimize common mode voltage at the measure ment input Active common mode reduction allows the Model 350 to operate in envi ronments that would otherwise be difficult to achieve the required measurement Lake Shore www lakeshore com CRYOTRONICS 4 CHAPTER 1 Introduction 1 4 3 Measurement Isolation 1 4 4 Configurable Display Samele e vj Optocouplers isolate the analog front end ofthe Model 350 from digital circuitry and the instrument chassis Optical isolation minimizes the effect of digital noise on the measurement and breaks ground loops The Model 350 offers a bright graphic liquid crystal display with an LED backlight that simultaneously displays up to eight readings You can show all four loops all inputs or if you need to monitor one input you can display just that one in greater detail Or you can custom configure each display location to suit your experiment Data from any input can be assigned to any of the locations and your choice of tem perature or sensor units can be displayed For added convenience you can also cus tom label each sensor input eliminating the guesswork in remembering or determining the location to which a sensor input is associated amp Rad Shield 27 8645 1 4 5 Use Additional Input Types with Option Cards 1 5 Sensor Selection Model 350 Temperature Controller The field installable input option cards a
122. and ESE 145 term 145 is the sum of the bit weighting for each bit Bit Bit Weighting Event Name 0 1 OPC 2 4 QXE 4 16 EXE 5 32 CME 7 128 PON Total 181 Event Status Enable Register Query KESE term bit weighting term nnn Referto section 6 2 5 for a list of event flags Standard Event Status Register Query KESR term bit weighting nnn The integer returned represents the sum ofthe bit weighting of the event flag bits in the Standard Event Status Register Refer to section 6 2 5 for a list of event flags IDN Input Returned Format Example OPC Input Remarks OPC Returned Remarks kRST Input Remarks kSRE Input Format Remarks Example kSRE Input Returned Format 6 6 1 InterfaceCommands 139 Identification Query IDN term lt manufacturer gt lt model gt lt instrument serial gt lt option serial gt lt firmware version gt term s 4 s 8 s 7 s 7 n n manufacturer Manufacturer ID model Instrument model number instrument serial Instrument serial number option card serial Option card serial number firmware version Instrument firmware version LSCI MODEL350 1234567 1234567 1 0 Operation Complete Command koPC term Generates an Operation Complete event in the Event Status Register upon comple tion of all pending selected device operations Send it as the last command in a com mand string Operation Complete Qu
123. ary and Symbols 13 Equipment protected throughout by double insulation or reinforces insulation equivalent to Class II of IEC 536 see Annex H CAUTION High voltages danger of electric shock background color yellow symbol and outline black CAUTION or WARNING See instrument documentation background color yellow symbol and outline black Lake Shore www lakeshore com CRYOTRONICS 14 CHAPTER 1 Introduction Model 350 Temperature Controller 2 3 1 DilutionRefrigeratorTerminology 15 Chapter 2 Cooling System Design and Temperature Control 2 1 General 2 2 Useful Temperature Range 2 3 Cryogenic Cooling System Terminology 2 3 1 Dilution Refrigerator Terminology Selecting the proper cryostat or cooling source is probably the most important deci sion in designing a temperature control system The cooling source defines minimum temperature cool down time and cooling power Information on choosing a cooling source is beyond the scope ofthis manual This chapter provides information on how to get the best temperature measurement and control from cooling sources with proper setup including sensor and heater installation The lowest temperature at which the Model 350 can make useful temperature mea surements is difficult to define In a practical sense the instrument is limited by its need for four electrically conductive leads to be attached to a sensor and that sensor attached to a cold surface Heat con
124. ation section includes all keys Definitions to the left of the number pad and the Menu Number Pad section includes the standard 12 number pad keys and the Up Down Escape and Enter keys FIGURE 4 1 The Direct Operation keys provide one touch access to the most often used functions of the Model 350 The Number Pad keys with the exception ofthe dec imal point key are dual function keys If the instrument is in the number entry mode the keys are used to enter numbers If itisin normal operating mode the number keys provide menu entry points An abbreviated description of each key is provided as fol lows A more detailed description of each function is provided in section 4 3 to section 4 5 4 2 1 1 Direct Operation Keys Press these keys for quick access to the display screens for the associated sensor input or Input Display mode Press once for a temporary display that will time out in 10 s at which point the dis play returns to the assigned Display Mode setting Press the same key again or press Escapebe A B C andD fore the timeout period to return the display to the previous Display Mode setting Pressing and 4313 ied holding one of these keys for 3 s causes the associated Input Display to become the new perma ES nent Display Mode setting indicated by an audible beep When the Model 3062 4 channel scanner option is installed pressing the D button cycles the dis play through the display screens for each o
125. ator as 1 string m Guarantee that no other communication is started for 50 ms after the last char acter is transmitted m Notinitiate communication more than 20 times per second 6 4 Ethernet Interface 6 4 1 Ethernet Configuration 6 4 EthernetInterface 121 When issuing queries or queries and commands together the user program should m Properly format and transmit the query including the terminator as 1 string m Prepare to receive a response immediately m Receive the entire response from the instrument including the terminator m Guarantee that no other communication is started during the response or for 50 ms after it completes m Notinitiate communication more than 20 times per second Failure to follow these simple rules will result in inability to establish communication with the instrument or intermittent failures in communication The Ethernet interface provides a means of connecting the Model 350 to an Ethernet based computer network Ethernet networks provide the ability to communicate across large distances often using existing equipment the internet pre existing local networks The Ethernet interface of the Model 350 provides the ability to use TCP socket connections section 6 4 3 to send commands and queries to the instru ment using the common command set detailed in section 6 6 The Model 350 has an embedded web interface that provides status information and additional utilities section 6 5 Menu Navigation
126. be used when the capacitance option is installed butthe capacitance and standard inputs cannot be used simultaneously Refer to section 7 4 2 to install the Model 3061 Capacitive sensors in the Model 350 do not support temperature conversion there fore temperature response curves cannot be selected Any feature ofthe Model 350 that requires temperature to operate is not supported with the option card Refer to section 3 5 8 for more information on using the Model 3061 4 4 6 1 Range Selection The capacitance option input has two input voltage ranges 15 nF and 150 nF The lowerrange is specified to 15 nF but can read up to 25 nF and is recommended for CS 401 series sensors The higher range is specified to 150 nF but can read up to 250 nF and is recommended for CS 510 series sensors Menu Navigation Input Setup nput D Sensor Type Capacitance Interface Command INTYPE Lake Shore www lakeshore com CRYOTRONICS 70 CHAPTER 4 Operation 4 4 7 4 Channel Scanner Input Setup Model 3062 Only Model 350 Temperature Controller 4 4 6 2 Temperature Coefficient Selection Capacitance sensors can have both a positive and negative temperature coefficient slope They have a positive temperature coefficient at very low temperatures and a negative temperature coefficient at warmer temperature Sensor data sheets detail where the coefficient changes There is often a temperature range where the sensor is not usable Temperatu
127. both in the parts used and their junctions There is a conflict between the best sensor location for measurement accuracy and the best sensor location for control For measurement accuracy the sensor should be very near the sample being measured which is away from the heating and cooling sources to reduce heat flow across the sample and thermal gradients The best con trol stability is achieved when the feedback sensor is near both the heater and cooling source to reduce thermal lag If both control stability and measurement accuracy are critical it may be necessary to use two sensors one for each function Many tempera ture controllers including the Model 350 have multiple sensor inputs for this reason Cryogenic designers understandably want to keep the thermal mass of the load as small as possible so the system can cool quickly and improve cycle time Small mass can also have the advantage of reduced thermal gradients Controlling a very small mass is difficult because there is no buffer to adsorb small changes in the system Without buffering small disturbances can very quickly create large temperature changes In some systems it is necessary to add a small amount of thermal mass such as acopper block in order to improve control stability 2 12 5 System Non Linearity 2 13 PID Control 2 13 1 Proportional P 2 13 2 Integral I 2 12 5 SystemNon Linearity 37 Because of nonlinearities a system controlling well at one temperature ma
128. breakpoint number and press Enter The highlight moves to the sensor value ofthe selected pair 2 Usethe Number Entry method to edit the value Refer to section 4 2 1 2 for details on the Number Entry method 3 Oncethe new sensor value is entered press Enterto highlight the temperature value 4 Usethe Number Entry method to enterthe new temperature value Press Enter atthis pointto store the new breakpoint pair 6 Press Escape at any time when a sensor ortemperature value is highlighted to cancel any changes to either ofthe values and return the highlightto the break point number n If the sensor value entered is not between the previous breakpoint sensor value and the following breakpoint sensor value then the new breakpoint pair will be moved to the position in the curve that bounds the sensor value of the new breakpoint pair If the pair is moved a message will be displayed to indicate to the location to which the breakpoint pair was moved Curve Entru Curue Entru 45 Ak ct J k k k k i K NEC i aaa a 14s 50 000 Kw Y FIGURE 5 7 Left Scroll to highlight a breakpoint number Middle Press the enter key to highlight the sensor value of the selected pair Right Press the enter key again and the temperature value is highlighted Menu Navigation Curve Entry Edit Curve 21 59 Curve Points 1 200 Interface Command CRVPT Lake Shore www lakeshore com CRYOTRONICS 98 CHAPTER 5 Advanced Operat
129. but there is little advantage in using wire smaller than 20 AWG to 22 AWG outside the cryostat Inside the cryostat smaller gauge wire is often desirable It is recommended to use twisted heater leads Large changes in heater current can induce noise in measurement leads and twisting reduces the effect It is also recom mended to run heater leads in a separate cable from the measurement leads to fur ther reduce interaction There is a chassis ground point at the rear panel of the instrument for shielding the heater cable if necessary The cable shield can be tied to this point using a 3 18 mm 4 spade terminal or ring connector The shield should not be connected at the opposite end of the cable and should never be tied to the heater output leads For best noise performance do not connect the resistive heater or its leads to ground Also avoid connecting heater leads to sensor leads or any other instrument inputs or outputs The heater output circuitry in the Model 350 is capable of sourcing 75 W of power This type of circuitry can generate some electrical noise The Model 350 was designed to generate as little noise as possible but even noise that is a small percentage of the output voltage or current can be too much when sensitive measurements are being made near by Heater output noise can be most detrimental when controlling at very low temperatures Heater Output 2 uses a fully linear power supply to minimize heater noise The switchi
130. by itself but itis even more powerful when used with otherfeatures We recommend using zone mode with setpoint ramping section 4 5 1 5 7 Referto section 5 3 for detailson setting up zones Referto section 2 13 for a detailed discussion of PID control Menu Navigation Output Setup Output 1 2 3 or 4 0utput Mode Zone 4 5 1 4 3 Open Loop Mode Open Loop output mode allows you to directly set the output using only the Manual Output and Range parameters This guarantees constant current to the load but it does not actively control temperature Any change in the characteristics of the load will cause a change in temperature You can configure any output to Open Loop mode When an output is configured in this mode the Manual Output and Heater Range parameters become available in the Output Setup menu for setting the output For convenience the Control Input param eter can be used to assign a sensor input which then allows the output to be dis played on the front panel when using that sensor input s display mode When displayed on the front panel the Manual Output and Heater Range direct operation keys can be used for one touch access to these settings Refer to section 4 3 1 for details on configuring display modes Since there is no sensor feedback in open loop mode there is nothing to prevent the sys tem from being overheated We recommend using the Temperature Limit feature to help protect the system from overheating Refer to
131. cale mode click Reset Zoom Pan Ascreenshot ofthe currently displayed chart can be copied to the clipboard saved in the PNG image format or printed directly to a printer using the context menu that appears when right clicking on the chart Other chart properties such as colors and fonts can be customized through this context menu by clicking Properties Note that changes to these chart properties are not saved when the application is closed so the default values will be restored when reopening the chart recorder utility 6 5 4 4 Utilities Panel The utilities panel 11 provides added functionality to assist the user in various com mon tasks associated with user applications Three tabs provide a means of selecting between the three utili ties Command Line provides command line access for sending commands and queries to the instrument To send a command or query type the command or query into the Command text box and click Send Query responses are displayed in the Response box below Click Command Summary to pull up the list of command line commands and queries supported by the instrument 6 5 4 EmbeddedChartRecorder 135 Notes provides a means of adding notes to the log file while logging data The note will be added to the notes column ofthe log file at the row associated with the most recently acquired data point To add a note simply add text to the text box next to the Save Note button then click Save Note Notes will be appende
132. ce less than 50 O orto 50 O forany higher heater resistance The user max current setting is useful when using a non standard heater resistance value Refer to section 4 5 1 1 1 for more information on User Max Current TABLE 4 14 pro vides examples of different heater resistances and max current settings and the resulting maximum heater power The maximum heater powers in bold representthe discrete current limits available under the Max Current setting for 25 O and 500 heaters Menu Navigation Output Setup Output 1 Heater Resistance 25 Q or 50 Q Output Setup Output 1 Max Current User 0 707 A 1A 1 414 A or 2 A Default Heater Resistance25 Q Output 1 Max Current gt 2 A Output 2 Max Current gt 1 414 A Interface Command HTRSET 4 5 1 1 1 User Max Current When using a heater that is not 25 Q 100 W or 50 Q 50 W the provided discrete cur rent limits may not be appropriate The User Max Current setting is available for this case The optimal maximum current value should be calculated based on the heater s power rating or the maximum desired heater output power whichever is lower The heater output compliance voltage 50 V for both heater outputs should also be taken into account in orderto maximize heater setting resolution This calculated current limit can then be entered using the User Max Current setting To calculate the Max Current setting based on a heater or load power limit calculate current I using both
133. configured with the capacitance sensor input option card Capacitance inputs are not installed on the standard Model 350 but it can be added by purchasing the Model 3061 capacitance input option Refer to section 7 4 for installation of the Model 3061 The Model 3061 adds a capacitance input to the Model 350 appearing on the display as input D The card has separate voltage feedback and current excitation for the sen sor The Model 3061 is intended to control temperature in strong magnetic fields using a Lake Shore Model CS 501 capacitance temperature sensor The standard inputs remain in the instrument and are fully functional Upon changing control to the capacitive sensor the PID values will need to be optimized The Model 350 does not support temperature conversion for the capacitance input Thetemperature response of capacitance sensors shifts with thermal cycling making calibration unpredictable All Model 3061 option measurement and control must be done in sensor units With this option two sensors should be installed at the control point Use a resistive sensor in one ofthe standard inputs to establish a control tem perature and stabilize the system in a low magnetic field Before increasing the field strength shift control to the capacitance sensor to maintain the current temperature 3 5 9 Thermocouple Sensor Inputs Thermocouple Model 3060 3 5 9 Thermocouple Sensor Inputs Thermocouple Model 3060 51 3 5 8 1 Wiring Guard
134. ctionality for the next data acquisition task When Start is pressed the parame ters in the configuration panel are used to determine m Sample period 13 the rate at which to acquire readings from the instrument in milli seconds Number of data points to log 14 the number of data points to log if logging to a file Log file 15 the path ofthe file to use for logging data if logging to a file Chart only 16 if selected acquired data is only charted and is not logged to a file Readings 17 the readings and units where applicable to take during data acquisition Lake Shore www lakeshore com CRYOTRONICS 134 CHAPTER 6 Computer Interface Operation Model 350 Temperature Controller The configuration panel can be collapsed to increase the size ofthe chart To collapse the configuration panel simply click on Collapse configuration panel 12 When col lapsed the same button becomes an Expand Configuration Panel button that can be used to restore the configuration panel on the form When data acquisition is in prog ress the configuration panel controls are disabled butthe current settings can still be seen 6 5 4 2 Starting Data Acquisition Once the parameters in the configuration panel are set as desired simply click Start to begin data acquisition If you are logging data to a file the Number of Data Points to Log parameter is used to determine how many data points to take before terminat ing data acquisition
135. ctor plug into the socket on the option board Orient the ribbon cable connec tor plug so that the arrow nub slides into the plug slot and the ribbon cable exits downward FIGURE 7 5 Plug the other end ofthe cable into the main board option connector J12 FIGURE 8 11 Slide the top panel forward in the track provided on each side ofthe unit Replace the rear plastic bezel by sliding itstraight into the unit Use a small Phillips screwdriver to replace the two top cover screws and the one bottom cover screw Use the hex driver to replace the 4 screws on the sides ofthe top covers Tighten the two rear bottom screws Replace the power cord in the rear ofthe unit and set the power switch to On To verify option card installation check the instrument information by pressing and holding the Escape key Refer to section 8 7 2 for more information on instru ment information Lake Shore www lakeshore com CRYOTRONICS 164 CHAPTER 7 Options and Accessories Model 350 Temperature Controller E Chapter 8 Service 8 1 General This chapter provides basic service information for the Model 350 temperature con troller Customer service of the productis limited to the information presented in this chapter Factory trained service personnel should be consulted if the instrument requires repair 8 2 USB This section provides USB interface troubleshooting for issues that arise with new Troubleshooting installations existing installation
136. d 28 K Points 2 and 3 improve temperatures above 28 K m Point 2 calibration data point at or near the boiling point of nitrogen 77 35 K Temperatures outside 50 K to 100 K are not allowed This data point improves accuracy between 28 K and 100 K Points 2 and 3 together improve accuracy to room temperature and above m Point 3 calibration data point near room temperature 305 K Temperatures out side the range of 200 K to 350 K are not allowed 5 10 2 SoftCal Accuracy With DT 400 Series Silicon Diode Sensors 5 10 2 SoftCal Accuracy With DT 400 Series Silicon Diode Sensors 101 SoftCal Point One SoftCal Point Two SoftCal Point Three Liquid helium Liquid nitrogen Room temperature boiling point boiling point point 4 2K 77 35K 305K Ff ES 0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 2 10K 50 100K 200 325K FIGURE 5 8 Acceptable temperature range for DT 400 series silicon diode SoftCal sensors A SoftCal calibration is only as good as the accuracy ofthe calibration points The accuracies listed for SoftCal assume 0 01 K for 4 2 K liquid helium 0 05 K for 77 35 K liquid nitrogen and 305 K room temperature points Users performing the SoftCal with Lake Shore instruments should note that the boiling point of liquid cryogen though accurate is affected by atmospheric pressure Use calibrated stan dard sensors if possible One point SoftCal calibrations for applications under 30 K ar
137. d 4 115 006 T Detachable 120 VAC Line Cord MAN 350 Model 350 Temperature Controller User s Manual Sensor Heater Cable Assembly 10 Feet Cable assembly for 2 sensor inputs and 1 heater out G 112 325 put Approximately 3 m 10 ft long Requires 2 to use 4 sensors and 2 heaters Refer to FIGURE 7 1 Sensor Heater Cable Assembly 20 Feet Cable assembly for 2 sensor inputs and 1 heater out G 112 326 put Approximately 6 m 20 ft long Requires 2 to use 4 sensors and 2 heaters Refer to FIGURE 7 1 6201 IEEE 488 Cable 1 m 3 ft long IEEE 488 computer interface cable CAL 350 CERT1 Instrument calibration recalibration with certificate TABLE 7 4 Accessories Lake Shore www lakeshore com CRYOTRONICS 160 CHAPTER 7 Options and Accessories CAL 350 DATA Description of Accessories Instrument calibration recalibration with certificate and data ES 2 20 Stycast Epoxy 2850 FT Catalyst 9 20 packets 2 g each Stycast is a common highly versa tile nonconductive epoxy resin system for cryogenic use The primary use for Stycast is for vacuum feedthroughs or permanent thermal anchors Stycast is an alternative to Apiezon N Grease when permanent sensor mountings are desired ID 10 XX Indium Solder Disks Quantity 10 Indium is a semi precious non ferrous metal softer than lead and extremely malleable and ductile It stays soft and workable down to cryogenic tem peratures Indium can be u
138. d is often used as a calorimeter cement When soaked into cigarette paper it makes a good high thermal conductivity low electrical conductivity heat sinking layer Maximum operating temperature 423 K 150 C Wire Lake Shore Cryogenic Wire Lake Shore sells the following types of cryogenic wire DT Duo Twist MN Single Strand MW Manganin NC Nichrome Heater ND Heavy Duty QL Quad Lead and QT Quad Twist Lake Shore Coaxial Cable Lake Shore sells the following types of coaxial cable CC Ultra Miniature Coaxial Cable SR Semi Rigid Coaxial Cable CRYC CryoCable Accessories included with a new Model 350 TROHS compliant Model 350 Temperature Controller TABLE 7 4 Accessories 7 4 FieldInstallation 161 BLK GREEN S OCX REN rum VENE POKER WA FIGURE 7 1 Model 350 sensor and heater cable assembly 10 ft P N G 112 325 20 ft P N G 112 326 7 4 Field This section provides procedures for field installing the rack mount and the option Installation cards 7 4 1 Rack Mounting The Model 350 can be installed into a 482 6 mm 19 in rack mount cabinet using the optional Lake Shore Model RM 1 Rack Mount Kit The kit contains mounting ears handles and screws that adapt the front of the instrument to fit into a 88 9 mm 3 5 in tall full rack space Additional support may be required in the rear of the instrument and to relieve strain on heavy cables The mounting ears are painted and do
139. d noise It is also effective to move the instrument and leads away from noise sources because field strength reduces by the inverse cube of distance Even with proper installation itis impossible to eliminate induced noise High resis tance ranges are affected more because the leads create a more efficient antenna when they are terminated at a high resistance Ground loops produce noise that acts similar to induced noise but the cause of the noise is different Current is generated in any conductive circuit or loop when that loop contains changing current or magnetic field In measurements this problem is commonly referred to as a ground loop and generally results when improperly grounded instruments are exposed to AC line current Isolation reduces ground loop noise by breaking the loop or circuit The Model 350 has a well designed power sup ply and uses optical isolation between the instrument chassis and measurement cir cuits Careful installation is necessary to take advantage ofthe isolation The current source and amplifiers inside the Model 350 make a contribution to mea surement noise Circuits were carefully chosen to maintain good noise performance over a wide resistance range without generating high leakage currents that could self heat sensors Instrument noise specified in TABLE 1 3 is dominated by amplifier noise When high resistance sensors 10 kO are measured the noise measured becomes dominated by the thermal noise ofthe re
140. d the Manual Output parameter is set in these units Available full scale cur rent and power are determined by the heater resistance max current setting and heater range The heater output display is a calculated value intended to aid in system setup and tun ing It is not a measured value and may not accurately represent actual power in the heater Menu Navigation Output Setup Output 1 2 Heater Out Display Current or Power Default Current Interface Command HTRSET 4 5 1 4 Output Modes The heater outputs can be configured in one offour output modes Off Closed Loop PID Zone or Open Loop The Off mode prevents current from being sourced to the given output Closed Loop PID is the mode most often used for controlling tempera ture Zone mode builds on the Closed Loop mode by providing automatic changing of control parameters at up to ten different temperature zones Open Loop mode pro vides a means of applying a constant current or voltage for outoputs 3 and 4 to the output Menu Navigation Output Setup Output 1 2 3 or 4 0utput Mode Off Closed Loop PID Zone Open Loop Default Off Interface Command OUTMODE 4 5 1 4 1 Closed Loop PID Mode The Closed Loop PID mode is the most commonly used closed loop control mode for tightly controlling temperature using the heater outputs of the Model 350 In this mode the controller attempts to keep the load at exactly the user entered setpoint temperature To d
141. d the oscillation period ofthe load It helps describe the dominanttime constant ofthe load which is used in setting integral 11 Reduce the proportional setting by half The appropriate proportional setting is one half of the value required for sustained oscillation in step 8 See FIGURE 2 4 b Continue to Tuning Integral section 2 14 3 12 There are a few systems that will stabilize and not oscillate with a very high pro portional setting and a proper heater range setting For these systems setting a proportional setting of one half ofthe highest setting is a good starting point Continue to the Tuning Integral section 2 14 3 When the proportional setting is chosen and the integral is set to O off the Model 350 controls the load temperature below the setpoint Setting the integral allows the Model 350 control algorithm to gradually eliminate the difference in tem perature by integrating the error over time See FIGURE 2 4 d An integral setting that is too low causes the load to take too long to reach the setpoint An integral setting that is too high creates instability and can cause the load temperature to oscillate 1 Beginthis part ofthe tuning process with the system controlling in proportional only mode 2 Usetheoscillation period ofthe load that was measured in section 2 14 2 in sec onds Divide 1000 by the oscillation period to getthe integral setting 3 Enterthe integral setting into the Model 350 and watch the load te
142. d to the note history text box along with a time stamp If a note is saved while not currently logging data to a file the note will only appear in the note history text box and will only be avail able while the application is running Control provides easy access to the control functions ofthe instrument The P I D Manual Output Setpoint and Heater Range settings can be configured here for each control loop on the instrument The current configuration ofthe given control loop is displayed when the Loop radio button is selected To update these parameters on the instrument first select the loop to update by choosing a Loop radio button Then update the values in the Control panel and click Send Each control loop must be updated independently so once the values in the Control panel are updated click Send before clicking another Loop radio button The utilities panel can be collapsed to increase the size ofthe chart To collapse the utilities panel click Collapse Utilities Panel 10 When collapsed the same button becomes an Expand Utilities Panel button that can be used to restore the utilities panel on the form 6 5 4 5 Menu The standard dropdown menu includes the following sections File 1 m Interface Configuration can be used to configure the remote interface connec tion to the instrument m Exit closes the Chart Recorder application Log Chart 2 m Configure Log Chart simply expands the configuration panel if c
143. dd additional input types The Model 3060 adds thermocouple capability The Model 3061 adds capacitance sensor inputs The Model 3062 adds 4 Cernox platinum diode input channels While the option cards can be easily removed it is not necessary as the standard inputs remain functional when the options are not being used Cernox thin film RTDs offer high sensitivity and low magnetic field induced errors over the 0 1 K to 420 K temperature range Cernox sensors require calibration Platinum RTDs offer high uniform sensitivity from 30 K to over 800 K With excellent reproducibility they are useful as thermometry standards They follow a standard curveabove 70 K and are interchangeable in many applications Silicon diodes are the best choice for general cryogenic use from 1 4 K to above room temperature Silicon diodes are economical to use because they follow a standard curve and are interchangeable in many applications They are not suitable for use in ionizing radiation or magnetic fields Capacitance sensors are ideally suited for use in strong magnetic fields because they exhibit virtually no magnetic field dependence They can be used from 1 4 K to 290 K 1 5 SensorSelection Model Useful range Magnetic field use Negative Cernox CX 1010 0 1K to 325 K1 T gt 2K amp BS19T Temperature Cernox CX 1030 HT 0 3 K to 420 K1 T gt 2K amp BS19T SSL TCU ES Cernox
144. des of the sensor being measured ensur ing that common mode voltages are not turned into normal mode voltages voltages are present between measurement leads The Model 350 has a built in hardware low pass filter with a 3dB frequency of 16 Hz Additional filtering is done in the instrument firmware as a linear average The input hardware settles about 100 milliseconds after a temperature sensor resis tance change if no range change is required When the firmware filter is turned on that filter settling time must be added to the hardware settling time to approximate overall settling The firmware filter can be set from 2 point to 64 points See section 4 4 10 for more details Range change requires additional settling because the internal circuits need time to reestablish their operating point The instruments A D sampling update rate is 10 readings per second and all read ings are available over the computer interface This rate allows the A D to capture any sensor changes that are able to pass through the input hardware The temperature control loop analog voltage outputs and max min capture are updated with each A D reading The effect of electrical noise is usually small and can be ignored when making routine measurements but noise can become important when measuring low temperatures The following paragraphs describe the most common noise source encountered with small signal measurements and some techniques that can help reduce the
145. digital computer that tells the Model 350 which functions to perform TABLE 6 1 defines the IEEE 488 capabilities and subsets for the Model 350 see res SH1 Source handshake capability RL1 Complete remote local capability DC1 Full device clear capability DTO No device trigger capability C0 No system controller capability T5 Basic Talker serial poll capability talk only unaddressed to talk if addressed to listen L4 Basic Listener unaddressed to listen if addressed to talk SRI Service request capability AH1 Acceptor handshake capability PPO No parallel poll capability E1 Open collector electronics TABLE 6 1 Model 350 IEEE 488 interface capabilities and their subsets Instruments are connected to the IEEE 488 bus by a 24 conductor connector cable as specified by the standard section 8 10 1 Cables can be ordered from Lake Shore as IEEE 488 Cable Kit 4005 or they can be purchased from other electronic suppliers Cable lengths are limited to 2 m 6 6 ft for each device and 20 m 65 6 ft forthe entire bus The Model 350 can drive a bus with up to ten loads If more instruments or cable length is required a bus expander must be used Lake Shore www lakeshore com CRYOTRONICS 106 CHAPTER 6 Computer Interface Operation 6 2 1 Changing IEEE 488 Interface Parameters 6 2 2 Remote Local Operation 6 2 3 IEEE 488 2 Command Structure Model 350 Temperature Controller Th
146. duced Electrical Noise 2 4 5 Measurement Speed and Filtering 21 2 4 4 4 Active Common Mode Reduction It is common for precision measurement equipment to use a differential input as the first stage of signal conditioning The differential input offers high impedance on both input voltage terminals to reduce the effect of common mode voltage voltage that acts on both leads at the same time Common mode voltage can come from many sources including external noise coupling into the lead wires and the instrument s own current source To reduce the effect of common mode voltage further the Model 350 includes an active common mode reduction circuit This circuit dynami cally adjusts the operation point of the current source output to minimize the com mon mode voltage seen at the measurement input 2 4 4 5 Matched Impedance Current Source The two current source output terminals on the Model 350 have the same source impedance similar to the voltage input terminals of a differential input that have the same input impedance The sensor being measured and all noise sources in the envi ronment see the same impedance on both current source leads when looking back into the instrument Traditional current sources with different impedance on each lead one lead grounded can lessen the common mode rejection of a differential input especially when measuring sensors with large resistances The common mode noise sources have the same effect on both si
147. duction and noise pick up in the sensor leads limitthe lowest temperature that can be achieved in this environment even before an instrument is attached The diminishing thermal contact between the sensor and cold surface at low temperatures exaggerate the problem In general the Model 350 was designed for measurements down to 100 mK There are many different cryogenic cooling systems used in laboratories today and it would be impossible to describe them all in this manual This section briefly illus trates the three most common cooling systems capable of reaching temperatures below 1 K This is an attempt to demonstrate how the Model 350 can be integrated into these systems for resistance measurement temperature measurement and tem perature control It is hoped that from these examples those knowledgeable in cryo genic techniques will become familiar with the terminology used throughout this manual and the intended operation of many ofthe instrument features Dilution refrigerators remain the workhorse of low temperature research down to approximately 5 mK to 10 mK So many variations of factory and home built units exist that it is unlikely that any two are identical FIGURE 2 1 illustrates only the most basic features Lake Shore www lakeshore com CRYOTRONICS 16 CHAPTER 2 Cooling System Design and Temperature Control Model 350 Temperature Controller 4 Helium Dewar Vacuum insulation He Reservoir Vacuum space 1K po
148. e www lakeshore com CRYOTRONICS 18 CHAPTER 2 Cooling System Design and Temperature Control 2 4 Model 350 Theory of Operation 2 4 1 Sensor Resistance Measurement Model 350 Temperature Controller 4He reservoir reservoir of liquid He at atmospheric pressure that provides bulk cooling down to 4 2 K Pre cools gasses entering the vacuum space and acts as a radiation shield for refrigeration components Vacuum space insulates refrigeration components and provides a clear workspace 1Kpot He evaporator pumped reservoir of He maintained at 1 K Used in the process of condensing 3He gas returning from pumping system Also used as a heat sink for measurement leads Good location for a temperature sensor for cool down monitor ing and troubleshooting Heat exchangers one or more heat exchangers serve to cool returning 3He liquid to nearthe temperature ofthe 3He evaporator Also used to heat sink measurement leads 3He Evaporator chamber where cooling action takes place Liquid 3He is pumped under vacuum to reduce its boiling pointto approximately 300 mK This is the best location for temperature control sensor and resistive heater The heater output can control temperature by driving the heater under closed loop PID control or open loop control Load sample holder end of the 3He evaporator where experiments can take place May either be part of or attached to the evaporator and is often designed for a unique pur pose Req
149. e initialization error will occur and the Autotune process will not be performed The TUNEST query can be used to check if an Autotune error occurred Display Contrast Command BRIGT contrast value term nn contrast value 1 32 Sets the display contrast for the front panel LCD Display Contrast Query BRIGT term lt contrast value gt term nn refer to command for description Celsius Reading Query CRDG lt input gt term a input A D D1 D5 for 3062 option lt temp value gt term tnnnnnn Also see the RDGST command CRVDEL Input Format Example CRVHDR Input Format Remarks Example CRVHDR Input Format Returned Format CRVPT Input Format Remarks Example CRVPT Input Format Returned Format Remarks 6 6 1 InterfaceCommands 143 Curve Delete Command CRVDEL curve term nn curve Specifies a user curve to delete Valid entries 21 59 CRVDEL 21 term deletes User Curve 21 Curve Header Command CRVHDR lt curve gt lt name gt lt SN gt lt format gt lt limit value gt lt coeffi cient gt term nn s 15 s 10 n nnn nnn n lt curve gt Specifies which curve to configure Valid entries 21 59 lt name gt Specifies curve name Limited to 15 characters lt SN gt Specifies the curve serial number Limited to 10 characters format Specifies the curve data format Valid entries 1 mV K 2 V K 3 Q K 4 log Q K lt limit value
150. e IEEE 488 address must be set from the front panel before communication with the instrument can be established Menu Navigation InterfaceS EnabledIEEE 488 Interface EEE 488 Address 1 to 31 Default IEEE 488 Normal operations from the keypad are referred to as local operations The Model 350 can also be configured for remote operations via the IEEE 488 interface or the Remote Local key The Remote Local key will toggle between remote and local operation During remote operations the remote annunciator LED will be illumi nated and operations from the keypad will be disabled The Model 350 supports several command types These commands are divided into four groups 1 BusControl section 6 2 3 1 a Universal m Uniline m Multiline b Addressed bus control 2 Common section 6 2 3 2 3 Device Specific section 6 2 3 3 4 Message Strings section 6 2 3 4 6 2 3 1 Bus Control Commands A bus control command can either be a universal or an addressed bus control A uni versal command addresses all devices on the bus Universal commands include uni line and multiline commands A uniline command message asserts only a single signal line The Model 350 recognizes two of these messages from the Bus Controller Remote REN and Interface Clear IFC The Model 350 sends one uniline command Service Request SRQ m REN Remote puts the Model 350 into remote mode m IFC Interface Clear stops current operation on the bus
151. e Model 350 will be displayed Click Cancel and refer to section 6 3 3 3 to install the driver from the web 6 Whenthe Found New Hardware wizard finishes installing the driver a confirma tion message stating the software forthis device has been successfully installed will appear Click Close to complete the installation 6 3 3 2 Installing the Driver From Windows Update in Windows XP 1 Connectthe USB cable from the Model 350 to the computer 2 Turn on the Model 350 3 Whenthe Found New Hardware wizard appears select Yes this time only and click Next 4 Select Install the software automatically Recommended and click Next 5 The Found New Hardware wizard should automatically connect to Windows Update and install the drivers If the Found New Hardware wizard is unable to connect to Windows Update or find the drivers a message saying Cannot Install this Hardware will be displayed Click the Cancel button and refer to section 6 3 3 3 to install the driver from the web 6 Whenthe Found New Hardware wizard finishes installing the driver a confirma tion message stating the wizard has finished installing the software for Lake Shore Model 350 Temperature Controller will appear Click Finish to com plete the installation 6 3 3 3 Installing the Driver From the Web The Model 350 USB driver is available on the Lake Shore website To install the driver it must be downloaded from the website and extracted Use the procedure i
152. e command ata time until communication is established Be sure to spell commands correctly and use proper syntax Attempt both Talk and Listen functions If one works but not the other the hard ware connection is working so look at syntax terminator and command format DPPH p Powerthe instrument off then on again to see ifitis a soft failure Power the computer off then on again to see if the IEEE card is locked up Verify that the address has not been changed on the instrument during a memory reset 4 Checkall cable connections w N 1 Check cable connections and length 2 Increase the delay between all commands to 50 ms to make sure the instrument is not being overloaded The fuse drawer supplied with the Model 350 holdsthe instrument line fuses and line voltage selection module The drawer holds two 5 mm x 20 mm 0 2 in x 79 in time delay fuses It requires two good fuses ofthe same rating to operate safely Refer to section 8 6 for details 120 Fuse FIGURE 8 1 Fuse drawer Use the following procedure to change the instrument line voltage selector To avoid potentially lethal shocks turn off the controller and disconnect it from AC power before performing these procedures 1 Identifythe line input assembly on the instrument rear panel See FIGURE 8 2 2 Turnthe line power switch OFF O 3 Remove the instrument power cord 4 With a small screwdriver release the drawer holding the line voltage selector
153. e input assembly in reverse order Verify voltage indicator in the line input assembly window Connect the instrument power cord Turn the power switch On I Q0 00 04 Y It is sometimes necessary to reset instrument parameter values or clear the contents of curve memory Both are stored in nonvolatile memory called NOVRAM but they can be cleared individually Instrument calibration is not affected except for Room Temperature Calibration which should be recalibrated after parameters are set to default values or any time the thermocouple curve is changed Lake Shore www lakeshore com CRYOTRONICS 168 CHAPTER 8 Service 8 7 1 Default Values The factory defaults can be reset and the user curves cleared using the Factory Reset menu To access the Factory Reset menu press and hold the Escape key for 5 s Once the menu appears set either Reset to Defaults or Clear Curves or both to Yes then highlight Execute and press Enter Input Setup General Interface Setup General Sensortype NTCRTD Sensor excitation 1mV Enabled id Filter Off Interface Setup IEEE Input name Input A B C D IEEE Address 12 Temperature limit OK Off Interface Setup Ethernet Default Input units Kelvin DHCP On Curve None Auto IP Off Input Setup Autorange On Static Subnet Mask 255 255 255 0 Current reversal On Static Gateway 192 168 0 1 Input Setup
154. e lowest range and write down the temperature rise if any Select the next highest heater range and continue the process until the load warms up to room temperature Do not leave the system unattended the heater may have to be turned off manually to prevent overheating If the load never reaches room tempera ture some adjustment may be needed in heater resistance or load The list of heater range versus load temperature is a good reference for selecting the proper heater range It is common for systems to require two or more heater ranges for good control over their full temperature Lower heater ranges are normally needed for lower temperature The Model 350 is of no use controlling at or below the temperature reached when the heater was off Many systems can be tuned to control within a degree or two above that temperature The proportional setting is so closely tied to heater range that they can be thought of as fine and course adjustments of the same setting An appropriate heater range must be known before moving on to the proportional setting 1 Allow the cooling system to cool and stabilize with the heater off 2 Place the Model 350 in closed loop PID mode tuning 3 Turn integral derivative and manual output settings to O 4 Enterasetpoint several degrees above the cooling system s lowest temperature 5 Entera low proportional setting of approximately 5 or 10 and enter the appro priate heater range as described in section 2 14
155. e operation Menu Navigation Interface gt Enabled USB The Ethernet interface is provided to allow the Model 350 to connect to a computer network A direct connection to a PC can also be achieved using a cross over Ethernet cable The advantages of using the Ethernet interface include the ability to communi cate directly with the Model 350 from any PC on the same local network and even from around the world via the Internet Refer to section 6 4 1 for details on Ethernet configuration Menu Navigation Interface gt Enabled Ethernet An IEEE 488 GPIB interface is provided for compatibility with legacy systems Refer to Chapter 6 for details on computer interface operation Menu Navigation Interface gt Enabled IEEE 488 4 6 3 1 Remote Local Local refers to operating the Model 350 from the front panel Remote refers to oper ating the controller via the IEEE 488 Interface The keypad is disabled during remote operation except for the Remote Local key and the All Off key When in remote mode the Remote front panel LED will be illuminated When in local mode the Remote LED will not be illuminated Menu Navigation Remote Local LED On Remote mode LED Off Local mode The keypad lock feature prevents accidental changes to parameter values When the keypad is locked some parameter values may be viewed but most cannot be changed from the front panel All Off is the only keypad function that remains active when the keypad i
156. e performed at liquid helium 4 2 K temperature Accuracy for the DT 470 SD 13 diode is 0 5 K from 2 K to 30 K with no accuracy change above 30 K Two point SoftCal calibrations for applications above 30 K are performed at liquid nitrogen 77 35 K and room temperature 305 K Accuracy for the DT 470 SD 13 diode sensor is as follows 1 0K 2 K to lt 30 K no change below 30 K 0 25 K 30 K to lt 60 K 0 15 K 60 K to lt 345 K 0 25 K 345 K to lt 375 K 1 0K 375 to 475 K TABLE 5 6 2 point SoftCal calibration accuracy for DT 470 SD 13 diode sensors Three point SoftCal calibrations are performed at liquid helium 4 2 K liquid nitro gen 77 35 K and room temperature 305 K Accuracy for the DT 470 SD 13 diode sensor is as follows 0 5K 2 Kto lt 30K 0 25 K 30 K to lt 60 K 0 15 K 60 K to lt 345 K 0 25 K 345 K to lt 375 K 1 0K 375to475K TABLE 5 7 3 point SoftCal calibration accuracy for DT 470 SD 13 diode sensors Lake Shore www lakeshore com CRYOTRONICS 102 CHAPTER 5 Advanced Operation 5 10 3 SoftCal With Platinum Sensors 5 10 4 SoftCal Accuracy With Platinum Sensors Model 350 Temperature Controller The platinum sensor is a well accepted temperature standard because of its consis tent and repeatable temperature response above 30 K SoftCal gives platinum sen sors better accuracy than their nominal matching to the DIN 43
157. ead measurement whenever possible Do not connect sensor leads to chassis or earth ground Use twisted shielded cable outside the cooling system Attach the shield pin on the sensor connector to the cable shield Do not attach more than one cable shield at the other end ofthe cable Lake Shore www lakeshore com CRYOTRONICS 50 CHAPTER 3 Installation 3 5 7 Sensor Polarity 3 5 8 Capacitance Sensor Inputs Model 3061 Model 350 Temperature Controller Run different inputs and outputs in their own shielded cable Use twisted wire inside the cooling system Use similar technique for heater leads Use a grounded receptacle for the instrument power cord Consider ground strapping the instrument chassis to other instruments or computers This section describes the diode resistor sensor inputs Lake Shore sensors are shipped with instructions that indicate which sensor leads are which It is important to follow these instructions for plus and minus leads polarity as well as voltage and current when applicable Two lead resistors can operate with any lead arrangement and the sensor instructions may not specify Four lead resis tors can be more dependent on lead arrangement Follow any specified lead assign ment for four lead resistors Mixing leads could give a reading that appears correct but is not the most accurate Cathode P di 7 Anode FIGURE 3 6 DT 670 SD Diode sensor leads This section provides information for a Model 350
158. ead only parameter can be accessed using the View IP Config menu The possible LAN Status states are m Connected Static the IP address parameters have been successfully configured using the Static IP method m Connected DHCP the IP address parameters have been successfully configured using the DHCP method m Connected AutolP the IP address parameters have been successfully configured using the AutoIP method m Addr Not Acquired the IP address parameters were not successfully configured m Duplicate Init IP when initially attempting to connect to the network the Static IP address was found to be in use by another device already configured on the network The Model 350 interface will remain unconfigured until an available Static IP address is entered m Duplicate Ong IP an ongoing conflict occurred after being successfully con nected to the network because another device on the network was configured using the same IP address The Model 350 will automatically unconfigure and remain unconfigured until an available IP address is entered m Cable Unplugged the Ethernet cable is either unplugged at one end or has been damaged Lake Shore www lakeshore com CRYOTRONICS 126 CHAPTER 6 Computer Interface Operation 6 4 3 TCP Socket Communication Model 350 Temperature Controller m Module Error the Model 350 has lost contact with the Ethernet module this may indicate a damaged Ethernet module m Acquiring Address the Model
159. easure ment to be valid Some installation suggestions for temperature sensors are given in section 3 5 A sensor self heats when the electrical power being put into the measured sensor resistance is large enough to warm the sensor above the temperature of its surround ings Electrical power gets into the sensor from both the necessary excitation current and undesirable noise Errors from self heating are dangerous because they can eas ily go undetected One strategy for detecting these errors is to understand the ther mal resistance of the sensor and predict its reaction to excitation and noise Self heating ATsp is a product of the sensor thermal resistance R expressed in kel vin per watt K W and excitation power P expressed in watts ATc R Ps P can be calculated as excitation current squared times measured resistance Re P I2R Lake Shore www lakeshore com CRYOTRONICS 24 CHAPTER 2 Cooling System Design and Temperature Control 2 6 4 Lead Resistance 2 7 Operating Trade Offs 2 7 1 Sensor Self Heating versus Excitation 2 7 2 Excitation vs Signal to Noise Model 350 Temperature Controller Section 1 5 includes typical sensor characteristics for Cernox Germanium Ruthe nium Oxide RTD s at 100 mK Estimates of the thermal resistance of typical sensors are used to demonstrate how excitation current must be reduced to compensate for the increase in thermal resistance at lower temperature Otherwise se
160. eater Range parameter of all outputs to Off This function is always active even if the keypad is locked or when it is in remote mode The analog outputs 3 and 4 are variable DC voltage sources that have a range from 10 V to 10 V The voltage is generated by a 16 bit D A converter with resolution of 0 3 mV or 0 003 of full scale This output can be configured to a Closed Loop PID Zone Open Loop Warm Up Supply or Monitor Out mode The Closed Loop PID mode can be used to control temperature It can also be set up for bipolar PID control which is useful when controlling a thermoelectric device Refer to section 5 4 for more infor mation on setting up thermoelectric devices The Open Loop mode can be used to set the output to a specific constant value Refer to section 4 5 1 4 3 for details on Open Loop Mode The Warm Up Supply mode uses the output to drive the programming inputfor an external power supply for the purpose of rapidly warming a system to a user specified temperature The Monitor Out mode uses the output to provide a volt age proportional to an input sensor reading to be used by an external device such as a data logger The voltage output is designed to provide up to 1 W into a 100 Q heater The output is cur rent limited to slightly over 100 mA and therefore a heater value less than 100 O can drive the output into current limit This condition will not damage the output but it can result in discontinuous temperature control
161. ecifies which relay to query 1 or 2 lt mode gt lt input alarm gt lt alarm type term n a n refer to command for description RELAYST Input Format Returned Format SCAL Input Format Remarks Example SETP Input Format Example Remarks SETP Input Format Returned Format 6 6 1 InterfaceCommands 155 Relay Status Query RELAYST relay number term n relay number Specifies which relay to query 1 or 2 status term n 0 Off 1 2 On Generate SoftCal Curve Command SCAL std dest SN 5 T1 value U1 value gt lt T2 value gt lt U2 value gt lt T3 value gt lt U3 value term n nn S 10 2nnnnnn nnnnnn snnnnnn Ennnnnn snnnnnn Ennnnnn std Specifies the standard curve from which to generate a SoftCal curve Valid entries 1 6 7 dest Specifies the user curve to store the SoftCal curve Valid entries 21 59 SN Specifies the curve serial number Limited to 10 characters T1 value Specifies first temperature point in kelvin U1 value Specifies first sensor units point T2 value Specifies second temperature point in kelvin U2 value Specifies second sensor units point lt T3 value gt Specifies third temperature point in kelvin lt U3 value gt Specifies third sensor units point Generates a SoftCal curve Refer to Paragraph 5 3 SCAL 1 21 1234567890 4 2 1 6260 77 32 1 0205 300 0 0 5189 term generates a three point SoftCal c
162. ecrease the manual excitation mode may be required to achieve the optimal performance The autorange feature of the Model 350 will increase the resistance range any time the sensor resistance is greater than full scale forthe range and it will decrease the range any time the measured resistance is below 20 of full scale The manual exci tation mode allows the user to choose the excitation current and the instrument does not change ranges automatically Small signal measurement instruments require special consideration during installa tion The following sections illustrate how to treat the instrument and its environ ment as a measurement circuit and in general how to integrate instruments like the Model 350 The circuit analogy is appropriate because almost anything electrical or electronic in a laboratory has the potential to induce electric field E field or mag netic field H field noise on the measurement Lake Shore www lakeshore com CRYOTRONICS 20 CHAPTER 2 Cooling System Design and Temperature Control Model 350 Temperature Controller Since electrical noise is everywhere itis betterto begin each installation with a good instrumentation strategy than itis to deal with noise after measurements are com promised Most parts of a good strategy are obvious some are not and even the best plans do not work all the time The Model 350 offers several features that help control noise and maintain signal integrity Specific recomm
163. ectors is often necessary in cryogenic systems Remember the thermocouple wire is the sensor any time it joins or contacts other metal there is potential for error B Temperature verification and calibration of room temperature compensation is difficult after the sensor is installed When possible keep a piece of scrap wire from each installation for future use m Thermocouples can be spot welded to the cryostat for good thermal anchoring as long as the cryostat has a potential close to earth ground 3 5 9 3 Grounding and Shielding Care must be taken to minimize the amount of noise contributed by ground loops when grounding thermocouple inputs For lowest measurement noise do not ground thermocouple sensors The instrument operates with slightly more noise if one of the thermocouples is grounded Be sure to minimize loop area when grounding both thermocouples The instrument does not offer a shield connection on the terminal block Twisting the thermocouple wires helps reject noise If shielding is necessary extend the shield from the oven or cryostat to cover the thermocouple wire but do not attach the shield to the instrument The following section covers the heater wiring from the vacuum shroud to the instru ment for both heater outputs Specifications are detailed in section 1 6 For help on choosing and installing an appropriate resistive heater refer to section 2 11 This section describes Output 1 and Output 2 3 6 2 Heater
164. ed for the system to range increase initial change using new control parameters stage of Pl and PID Autotuning Autotune heater range Model 350 Temperature Controller TABLE 5 1 Autotune stages Menu Navigation Autotune nput A B C D gt Autotune P Autotune PI Autotune PID 5 3 Zone Settings Lower Boundary Upper D ERTTEII pem ii Output Range Ramp Rate Control Input 5 3 ZoneSettings 87 The Model 350 allows you to establish up to ten custom contiguous temperature zones where the controller will automatically use pre programmed values for PID heater range manual output ramp rate and control input Zone control can be active for both control loops at the same time Configure the zones using 1 asthe lowest to 10asthe highest zone Zone boundaries are always specified in kelvin K The bottom ofthe first zone is always O K therefore only the upper limit is required for all subse quent zones Make a copy of FIGURE 5 1 to plan your zones To use the programmed zones the output mode must be set to Zone referto section 4 5 1 4 2 to set up Zone mode In Zone mode the instrument will update the control settings each time the setpoint crosses into a new zone If you change the settings manually the controller will use the new setting while itis in the same zone and will update to the programmed zone table settings when the setpoint crosses into a new zone The zone settings include a Control I
165. ed when a sensor does not follow a standard curve if you wish to display in temperature Otherwise the Model 350 will operate in sensor units like ohms or volts The Model 350 may not work over the full temperature range of some sensors The standard inputs are limited to operation above 100 mK even with sensors that can be calibrated to 20 mK SoftCal is a good solution for applications that do not require the accuracy of a pre cision calibration The SoftCal algorithm uses the well behaved nature of sensors thatfollow a standard curve to improve the accuracy of individual sensors A few known temperature points are required to perform SoftCal The Model 350 can also perform a SoftCal calibration You need to provide one two or three known tem perature reference points The range and accuracy ofthe calibration is based on these points section 5 10 Lake Shore offers two or three point SoftCal calibrated sensors that include both the large interpolation table and the smaller breakpoint interpolation table for 400 series diode and Platinum sensors Some types of sensors behave in a very predictable manner and a standard tempera ture response curve can be created for them Standard curves are a convenient and inexpensive way to get reasonable temperature accuracy Sensors that have a stan dard curve are often used when interchangeability is important Some individual sen sors are selected for their ability to match a published sta
166. ee ema ias 92 LENA EI ETT 94 5 8 Curve Numbers and Storage cece trei eect eee e ee heme 94 5 8 1 Curve Header Parameters 0 00 ccc cece cece cece cece teense eens 95 5 8 2 CUE BrEaKPOINtS sione merririseri tini RR lagna een baddies omeaware nd eneees 95 5 9 Front Panel Curve Entry Operations 6ccc cece cece e ee eee eee e ee eeeee 96 5 951 Edit CUNE sco ose e o a oe Ea RUPEE tenes oes 96 5 9 1 1 Edita Breakpoint Pair cece cece cece cee eee e eee e eee ees 97 5 9 1 2 Add a New Breakpoint Pair 0 0 cece cece cece cece eect e eee e tees 98 5 9 1 3 Delete a Breakpoint Pair 98 5 9 1 4 Thermocouple Curve Considerations s sse 98 5 9 2 VIEW CUIVE iu donee re EORR EUERDEEREPCpCHU ERES UE CE ER ELNE ET 99 5 9 3 Erase CUNE potaro i Ee ee e e ex ERO OX V qup oet RU PI RENE DOR ERE 99 5 94 COPY CURVE ie scious rtt esse ERE E OPE E ua apre DOO E D EN Mas 99 5 10 SoftCal M escis LER ree Ye E Rep Der IR dr n eese fern RE due 100 5 10 1 SoftCal With Silicon Diode Sensors sssssssssssssssssssssseeeee 100 5 10 2 SoftCal Accuracy With DT 400 Series Silicon Diode Sensors 101 5 10 3 SoftCal With Platinum Sensors 0 00 cece cece cece cece eens 102 5 10 4 SoftCal Accuracy With Platinum Sensors cece cece eee e eee 102 5 10 5 SoftCal CalibrationCurve Creation 2 0 0 0 00 cece cece cece eee e eens 103 6L General iiis few tL E BUR REE
167. ee esie 74 4 4 11 Temperature Limit pecsrires yerse p nip iA E e e EAEE S 74 4 4 12 Preferred Units ssssssssssssssssssssssseeeee eee emen 74 AAAS Max MIT oes sesto ee Rc EEE URL Id cela Tu Faeevat and UA NA 74 Output and Control SQtup ssc ore eer wie ge saved EE e E YR Y CIE RETI 74 454L Heater OUtDUtsS etre rende EE RI PI RF PRSE pero TpU ERU PEDRERSDDINNM 75 4 5 1 1 Max Current and Heater Resistance Output 1 Only 75 4 5 1 1 1 User Max CUIT DE cese eter exhi prix ES REX 75 4 5 1 2 Power Up Enable essi dti HERE HA RR EAE ERAS 76 4 5 1 3 Heater Out Display cece c cece eee eee rk inar 77 4 5 1 4 Output Modes cece eect eee e eee e een e ee een ed 77 4 5 1 4 1 Closed Loop PID MOde ccscececeneeceneneeceneeeeaenenes 77 45 142 Zone Mode iier Heer EP REI UA HE ERN TS 77 4 5 1 4 3 Open Loop Mode isssssssssssss ee 78 4 5 1 5 Control Parameters i ser tete EXPERS IU EAR Rd UC 78 4 5 1 5 1 Control Inputs iceex is e E AAEE EeEDUNM 78 4 5 1 5 2 Proportional P sss 79 4 5 1 5 3 Integral I i esee tace n ai e ete io bete 79 4 5 1 5 4 Derivative D ssssssssssssssssse e eee e eens 79 4 5 1 5 5 Manual OUtPUt cece cece aAa 80 4 5 1 5 6 SETPOINT i ccs e n tone euer p REF IHREN PERRA 80 4 5 1 5 7 Setpoint Ramping ssssssssssssssss teens 81 4 5 1 5 8 HeaterRanges isis phe er Gap DRPe rv POI 82 4 5 1 5 9 ALL OFF 7 eode i Ebr Ra REIN DEAE RR 83 4
168. endations on installation and lead wiring are given in Chapter 3 2 4 4 1 Shielding and Grounding Theory Begin any installation by separating noise sources from their targets Sources of E field and H field noise can be just about anything butthe targets are most often sig nal leads and other wires and cables H field coupling can be dramatically reduced with an inch or less of separation E field noise requires more separation but is also more easily shielded The best defense against E field noise is a conductive shield around the measure ment The more complete the shield the better Ideally it should extend from the instrument measurement circuits through the cables and down to the sensor This ideal approach is impractical in all but a few cryogenic systems The practical approach is to connect the shield from the measurement circuits through the room temperature cables to the conductive Dewar or vacuum chamber This creates a fara day shield around the entire measurement circuit If the shield or any other part of the measurement circuit is connected to Earth ground it is necessary to prevent ground loops that couple line frequency noise into the measurement A ground loop is created when measurement common is tied to Earth ground at more than one point The isolation ofthe instrument breaks the loop between the instrument power cord and the measurement common No loop is formed if measurement common is tied to Earth ground at only one
169. ent is also found in the Factory Reset menu The following information is provided Firmware date Serial number Option card type Ethernet version Firmware version Option card serial number The following are error messages that may be displayed by the Model 350 during operation Message Description DISABL Input is disabled Refer to section 4 4 NOCURV Input has no curve Refer to section 4 4 8 S OVER Input is at or over full scale sensor units S UNDER Input is at or under negative full scale sensor units T OVER Input at or over the high end of the curve T UNDER Input at or under the low end of the curve Cannot Communicate with Input uP The main microprocessor has lost communication with the sensor input microprocessor NOVRAM Corrupt Invalid data or contents in NOVRAM when this message appears options are provided for resetting the instrument to default values and for clearing all user curve locations 21 59 To perform the reset set the desired parameters to Yes then choose the Execute option Atemperature limit has been exceeded The temperature reading on a sensor input has exceeded the Temperature Limit set ting A detailed message will follow which includes a reference to which sensor input s temperature limit has been exceeded Keypad Locked An attempt has been made to change a parameter while the keypad is locked Refer to section 4 7 Heat
170. er Short Circuit Detected Ashort circuit condition has been observed on heater output 1 A detailed message will follow which includes a reference to which output caused the condition The output will be turned off when this occurs Heater Open Circuit Detected An open circuit condition has been observed on heater output 1 A detailed message will follow which includes a reference to which output caused the condition The output will be turned off when this occurs Heater Compliance TBD Invalid Calibration The calibration memory is either corrupt or is at the default uncalibrated state This message appears when the Model 350 is first powered on To clear the message and continue with instrument start up press the Escape and Enter keys simultaneously Invalid Option Card Calibration The installed option card calibration memory is either corrupt or is atthe default uncalibrated state This message appears when the Model 350 is first powered on To clearthe message and continue with instrument start up press the Escape and Enter keys simultaneously Firmware Update in Progress This indicates that the Model 350 is in firmware update mode TABLE 8 2 Error messages Instrument calibration can be obtained through Lake Shore Service Refer to section 8 14 for technical inquiries and contact information Lake Shore www lakeshore com CRYOTRONICS 170
171. er supplied data m Purchased Lake Shore sensors with SoftCal calibration include a set of calibra tion points in the calibration report The SoftCal calibration points are gener ated in a controlled calibration facility at Lake Shore for best accuracy The calibration points can be entered into the Model 350 so it can generate a curve If the CalCurve service is purchased with the calibrated sensor the curve is also generated at the factory and can be entered like any other curve Lake Shore silicon diode sensors incorporate remarkably uniform sensing elements that exhibit precise monotonic and repeatable temperature response For example the Lake Shore DT 400 Series of silicon diode sensors have a repeatable temperature response from 2 K to 475 K These sensors closely follow a standard curve SoftCal is an inexpensive way to improve the accuracy of an already predictable sensor Aunique characteristic of DT 400 Series diodes is that their temperature responses pass through 28 K at almost exactly the same voltage This improves SoftCal algo rithm operation by providing an extra calibration data point It also explains why SoftCal calibration specifications are divided into two temperature ranges above and below 28 K See FIGURE 5 8 m Point 1 calibration data point at or near the boiling point of helium 4 2 K Accept able temperature entries are 2 K to 10 K This data point improves between the calibration data point an
172. eries String of alphanumeric characters with length n Send these strings using surrounding quotes Quotes enable characters such as commas and spaces to be used withoutthe instrument interpreting them as delimiters nn String of number characters that may include a decimal point s n Dotted decimal format common with IP addresses Always contains 4 dot separated 3 digit decimal numbers such as 192 168 000 012 term Terminator characters Indicated a parameter field many are command specific state Parameter field with only On Off or Enable Disable states Floating point values have varying resolution depending on the type of command or query issued dd value TABLE 6 7 Interface commands key Clear Interface Command XCLS term Clears the bits in the Status Byte Register Standard Event Status Register and Opera tion Event Register and terminates all pending operations Clears the interface but not the controller The related controller command is RST Event Status Enable Register Command KESE bit weighting term nnn Each bit is assigned a bit weighting and represents the enable disable mask of the corresponding event flag bit in the Standard Event Status Register To enable an event flag bit send the command KESE with the sum ofthe bit weighting for each desired bit Refer to section 6 2 5 fora list of event flags To enable event flags 0 4 and 7 send the comm
173. ery OPC term 1 term Places a 1 in the controller output queue upon completion of all pending selected device operations Send as the last command in a command string Not the same as OPC Reset Instrument Command RST term Sets controller parameters to power up settings Service Request Enable Register Command SRE lt bit weighting gt term nnn Each bit has a bit weighting and represents the enable disable mask of the corre sponding status flag bit in the Status Byte Register To enable a status flag bit send the command SRE with the sum of the bit weighting for each desired bit Refer to section 6 2 6 for a list of status flags To enable status flags 4 5 and 7 send the command SRE 208 term 208 is the sum ofthe bit weighting for each bit Bit Bit Weighting Event Name 4 16 MAV 5 64 ESB 7 128 OSB Total 208 Service Request Enable Register Query SRE term lt bit weighting gt term nnn Refer to section 6 2 6 for a list of status flags Lake Shore www lakeshore com CRYOTRONICS 140 CHAPTER 6 Computer Interface Operation STB Input Returned Format Remarks TST Input Returned Format Remarks WAI Input Remarks ALARM Input Format Remarks Example Model 350 Temperature Controller Status Byte Query STB term bit weighting term nnn Acts like a serial poll but does not resetthe registerto all zeros The integer returned represents the sum o
174. es system characteristics and computes setting values for P I and D for you Once PID tuning parameters are chosen for a given setpoint the zone tuning feature automati cally switches sensor inputs for new setpoints enabling you to control temperatures from 100 mK to over 1000 K without interrupting your experiment As with all Lake Shore products the Model 350 product specifications are docu mented and verifiable in keeping with Lake Shore s tradition of performance assur ance even at application extremes The product is supported by a 3 year standard warranty our confirmation of quality and commitment for the long term Choosing the Model 350 for your ultra low temperature application means you ll have the ulti mate confidence in meeting your integration measurement and control needs now and into the future The Model 350 provides a unique patented matched impedance current source as its first defense against common mode noise Just as voltage input terminals for a dif ferential input have the same input impedance the two current source output termi nals of the Model 350 have the same source impedance This matched impedance ensures that common mode voltages do not become normal mode voltages With this strategy the differential input remains truly differential for accurate resistance mea surement To further reduce the effect of common mode voltage the Model 350 includes an active common mode reduction circuit This circuit dyn
175. es the display resolution for the sensor input type given in the speci fications section 1 6 1 Temperature control in sensor units can be unpredictable since most sensors do not have alinear response to temperature and therefore have can have different sensitivity in dif ferent temperature ranges If you change the Preferred Units from Sensorto temperature Kelvin or Celsius or from temperature to Sensor the Model 350 uses the assigned temperature curve to convert the Setpointto the new control units This provides minimal disruption in the control output if you change the Preferred Units parameter while the control loop is active Menu Navigation Setpoint See note below Default 0 0000 K Interface Command SETP When controlling in temperature setpoint is limited by the control input temperature curve s Setpoint Limit When controlling in sensor units setpoint is limited by the limits of the configured control sensor 4 5 1 5 7 Setpoint Ramping The Model 350 can generate a smooth setpoint ramp when the setpoint units are expressed in temperature You can set a ramp rate in degrees per minute with a range of Oto 100 and a resolution of 0 1 Once the ramping feature is turned on its action is initiated by a setpoint change When you enter a new setpoint the instrument changes the setpoint temperature from the old value to the new value atthe ramp rate A positive ramp rate is always entered it is used by the instrument to
176. f Lake Shore Cryotronics Inc The utilities embedded on the Model 350 are written using the Java programming language This theoretically allows the applications to run properly on many different platforms Windows Mac Linux etc although the applications are only sup ported on Microsoft Windows XP or Windows Vista and have been designed to work with the Java Runtime Environment JRE version 1 6 To download Java JRE please visit www java com Please note that without the proper JRE installed the utilities will not run properly Lake Shore www lakeshore com CRYOTRONICS 130 CHAPTER 6 Computer Interface Operation 6 5 1 Embedded Curve Handler Model 350 Temperature Controller The applications are launched from the Utilities web page using Java Web Start technology This allows the application to run outside ofthe web browser in a stand alone window The application can only be launched using the link in the embedded web page and cannot be permanently installed When launching the application multiple security warning messages may appear These messages are meant to pro tect youfrom malicious software that can cause harm to or compromise the security of your computer or your data The applications have been thoroughly tested and are considered by Lake Shore to be safe All software is imperfect and any software may be used by a malicious user for malicious purposes The Embedded Curve Handler util
177. for devices on a net work As an example when a web browser attempts to retrieve the web page at www lakeshore com the browser first performs a forward lookup on the assigned DNS server to attempt to retrieve the IP address that is represented by the name www lakeshore com If successful the web browserthen usesthe retrieved IP address to communicate with the web server that hosts the website at www lakeshore com Lake Shore www lakeshore com CRYOTRONICS 124 CHAPTER 6 Computer Interface Operation Model 350 Temperature Controller The Model 350 can be configured to communicate with a primary and a secondary DNS server using the Primary DNS Address and the Secondary DNS Address parame ters Multiple DNS servers are sometimes used for redundancy but multiple servers are not required and not all networks provide a DNS server DNS addresses can be configured automatically using the DHCP method if the network DHCP server is con figured to do so Your DHCP server must be configured appropriately to provide DNS server addresses Not all DHCP servers provide this functionality on your network Hostname A hostname is a name that is assigned to a device on a network On a Domain Name System DNS enabled network a hostname can be used alone when connecting from another device on the same domain orit can be combined with a domain name to connect to devices outside of the local domain For example www lakeshore com refers to the Lake Sho
178. from 2 to 200 data pairs breakpoints including a value in sensor units and a corresponding value in kelvin Using fewer than 200 breakpoints will not increase the number of available curve locations SoftCal generated curves are stored in user curve locations Each curve has parameters that are used for identification and to allow the instru ment to use the curve effectively The parameters must be set correctly before a curve can be used for temperature conversion or temperature control m Curve Number 1 to 59 m Name defaultsto the name User Curve for front panel entry A curve name of up to fifteen characters can be entered from eitherthe front panel or from the com puter interface Refer to section 4 2 3 for Alpha Numeric entry m Serial Number a sensor serial number of up to ten characters letters or numbers can be entered from either the front panel or from the computer interface Refer to section 4 2 3 for Alpha Numeric entry The default is blank m Format the format parameter tells the instrument what breakpoint data format to expect Different sensor types require different formats Formats for Lake Shore sensors are described in TABLE 5 3 Destriptlon Sensor Units Sensor Units P Full Scale Range Maximum Resolution VIK Volts vs kelvin 10V 0 00001 V alk Resistance vs kelvin for 10KQ 0 0010 platinum RTD sensors Log resistance vs kelvin for Vs NTC resistive sensors 4logQ 0 00001 log Q mv K Millivolts
179. front panel display to show the desired con trol loop information and then press Manual Output on the front panel A quick way to access the setting if the control loop information is not already being displayed is to press A B C or D on the front panel to temporarily display the control loop infor mation while the new setting is entered Referto section 4 3 for details on configuring the front panel display When an output is configured for Open Loop mode the Manual Output setting is available in the Output Setup menu This is because in the Open Loop mode no Con trol Input feedback sensor is required and if none is set then there would be no way to use the Manual Output front panel key to set the output unless using the Custom Display mode The Control Input parameter can be assigned to a sensor input that is not being used for control as a means of quickly accessing the Manual Output setting using the Manual Output front panel key Menu Navigation Manual Output 076 to 100 Default 0 Interface Command MOUT 4 5 1 5 6 Setpoint Use the Setpoint parameterto set the desired load temperature for a control loop Before entering a setpoint a control loop must be created by configuring an input sensor and assigning it to a control output using the Control Input parameter The Setpoint can be entered in either temperature units or sensor units based on the sen sor input s Preferred Units setting The Setpoint Ramping feature is av
180. fthe 5 input D channels Setpoint Press this key to enter the control setpoint for the currently displayed loop if applicable 4 5 1 5 6 Proportional P Press this key to manually adjust the Proportional control parameter for the currently displayed 45 152 loop if applicable Integral I Press this key to manually adjust the Integral control parameter for the currently displayed loop if 45 153 applicable Derivative D Press this key to manually adjust the Derivative control parameter for the currently displayed 45 154 loop if applicable For Outputs 1 and 2 this key allows selection of heater range 1 through 5 For Outputs 3 and 4 this j 4 5 1 5 8 Heater henge key allows selection of Output On Off except when in Monitor Out mode Manual Out Press this key to adjust the Manual Output setting of the currently displayed output if applicable 4 5 1 5 5 All Off Press this key to set the range for all Outputs to Off not applicable for Monitor Out mode 4 5 TABLE 4 2 Direct operation keys Model 350 Temperature Controller 4 2 1 2 Menu Number Pad Keys 4 2 2 Annunciators 59 Key Refer to section Press this key to configure features related to the inputs 4 4 for sensor input setup Input setup 3 4 4 8 for curve selection Press this key t fi feat lated to th ts includi fi ion of Output setup ress this key to configure features related to the outputs including configuration
181. fthe bit weighting ofthe status flag bits that are set in the Status Byte Register Refer to section 6 2 6 for a list of status flags Self Test Query TST term lt status gt term n lt status gt 0 no errors found 1 errors found The Model 350 reports status based on test done at power up Wait to Continue Command KWAI term Causes the IEEE 488 interface to hold offuntil all pending operations have been com pleted This is the same function as the OPC command except that it does not set the Operation Complete event bit in the Event Status Register Input Alarm Parameter Command ALARM lt input gt lt off on gt lt high value gt lt low value gt lt deadband gt lt latch enable gt lt audible gt lt visible gt term a n tnnnnnn nnnnnn nnnnnn n n n lt input gt Specifies which input to configure A D D1 D5 for 3062 option lt off on gt Determines whether the instrument checks the alarm for this input where 0 off and 1 on lt high setpoint gt Sets the value the source is checked against to activate the high alarm lt low setpoint gt Sets the value the source is checked against to activate low alarm lt deadband gt Sets the value that the source must change outside of an alarm condition to deactivate an unlatched alarm latch enable Specifies a latched alarm remains active after alarm condition correction where 0 off no latch and 1 on lt audible gt Specifies if the interna
182. g instability in the control parameter adjustment Observing system response to Control parameters are changed again System response is too slow to Autotune If not already using High 6 setpoint change using new control based on observation This is the final or the heater is too underpowered for the range increase initial parameters stage of P only Autotuning system to Autotune heater range Waiting for temperature to settle System response is too slow to Autotune 7 after returning setpoint to original Provides a baseline for subsequent stages or the new control parameters are caus Use a smaller initial P value value ing instability in the control Ensures that there is no temperature Seas Nus System response is too slow to Autotune 3 oscillation or excessive noise in the tem 8 Testing for temperature stability or the new control parameters are caus Use a smaller initial P value perature reading after control parameter Sae ing instability in the control adjustment First of 2 stages of observing system response to setpoint Compiles data for characterizin Vide 9 ys ee P SISTER Will not fail in this stage Not applicable change using new control the system parameters Second of 2 stages of observin P TOERIS 8 8 Control parameters are changed again System response is too slow or the heater If not already using High system response to setpoint a Bis 10 based on observation This is the final is too underpower
183. gb ot EUER RE PUO dade Re 65 Lake Shore www lakeshore com CRYOTRONICS Chapter 5 Advanced Operation Model 350 Temperature Controller 4 5 4 6 4 7 5 1 5 2 5 3 5 4 5 5 4 4 1 Negative Temperature Coefficient NTC Resistor Sensor Input Setup 66 4 4 2 Positive Temperature Coefficient PTC Resistor Sensor Input Setup 66 44 3 Range Seletin ient NARAON EN RE EEIT 66 4 4 4 Thermal Electromotive Force EMF Compensation sssssssssses 67 4 4 5 Thermocouple Sensor Input Setup Model 3060 Only 065 68 4 4 5 1 Internal Room Temperature Compensation 00e eee 68 4 4 5 2 Internal Room Temperature Compensation Calibration Procedure 68 4 4 6 Capacitance Sensor Input Setup Model 3061 Only ssssssssss 69 44 6 1 Range Selection i cceo ciere REED YRXERS URDAA RE ENNS 69 4 4 6 2 Temperature Coefficient Selection 0 cece cece rriren 70 4 4 6 3 Control Channel Changes cccceeee cece eect eee eeeaee ees 70 4 4 7 4 Channel Scanner Input Setup Model 3062 Only 00 cece ee 70 4 4 7 1 Type and Range Selection cece cece e eee ee eee eee ene eens 70 44 7 2 Update Rate aie Uta ERR dev nio peek p DP REL DINER 71 4 4 8 C rve Selection ioc EUR RR TEEIRORDEN NT EXP RECITYA URS RET 71 AAO Ellter ooetci ete pn a ea st ENSEM T RO EU estar er RO UA EU OSA 72 24 10 Inp t Nalrle 1sscsocceuosssspee e rE n e RN ROUX Ve sta eR R
184. ging is enabled the range will be automatically selected so that the excitation voltage is below 10 mV Refer to section 4 4 3 for details on manually selecting the range Current Reversal is also enabled by default in order to compensate for thermal EMF voltages Refer to section 4 4 4 for details on the Thermal EMF Compensation Current Reversal feature Menu Navigation Input Setup nput A B C or D Sensor Type PTC RTD Platinum Interface Command INTYPE The Model 350 is equipped with an autoranging feature that will automatically select the appropriate resistance range for the connected resistive temperature device In some cases it may be desirable to manually select the resistance range To manually select a resistance range set the Autorange parameter to Off then use the Range parameterto select the desired range Autorange will be On by default when everthe Sensor Type parameter is set to PTC RTD or NTC RTD Autorange is not avail able for the Diode sensor type 4 4 4 Thermal Electromotive Force EMF Compensation 4 4 4 Thermal Electromotive Force EMF Compensation 67 Menu Navigation Input Setup nput A B C or D Autorange Off or On Input Setup nput A B C or D CsRange See table below Default On Interface Command INTYPE SEITE Available Sensor Type ADE Range Maximum Sensor Power Current Excitation Excitation B Settings 100 1
185. h part ofthe IP address represents the subnet rout ing prefix and which part represents the device s address on the subnet Asubnet mask is most often given in dotted decimal notation such as nnn nnn nnn nnn where nnn is a decimal number from 0 to 255 When converted to a binary nota tion the 32 bit subnet mask should consist of a contiguous group of ones fol lowed by a contiguous group of zeros The ones represent which bits in the IP address refer to the subnet and the zeros represent which bits refer to the device address For example the default Static IP Address of the Model 350 is 192 168 0 12 and the default Static Subnet Mask is 255 255 255 0 Converting this subnet mask to binary shows that the first 24 bits are ones and the last 8 bits Lake Shore www lakeshore com CRYOTRONICS 122 CHAPTER 6 Computer Interface Operation Model 350 Temperature Controller are zeros This means that the first 24 bits of the Static IP Address 192 168 0 represent the subnet and the last 8 bits 12 represent the device m Gateway Address a gateway is a network traffic routing device that is used to route communication between networks If a gateway is not used then devices on a network can only communicate with other devices on that same network A Gateway Address is the IP address of the gateway on a network Contact the net work administrator for the gateway address for your network 6 4 1 2 Network Address Configuration Methods
186. he front panel display must be configured to show the Warm Up control loop for the Set point and Heater Range keys to be used Refer to section 4 2 and section 4 3 for details on front panel keypad operation and display setup The Power Up Enable feature determines if the output will remain on after power is cycled Refer to section 4 5 1 2 for details on the Power Up Enable feature Menu Navigation Output Setup Output 3 or 4 0utput Mode Warm Up Supply Interface Command OUTMODE The Warm Up Percentage parameter is used to determine the amount of voltage to apply to the unpowered output 3 or 4 when using Warm Up mode to control an external power supply The voltage applied will be the full scale output 10 V times the Warm Up Percentage For example if the Warm Up Percentage is set to 50 the control output voltage for the given unpowered output will be 50 of 10 V or 5 V when the output is on Menu Navigation Output Setup Output 3 or 4 Warm Up Percentage gt 0 to 100 Default 100 Interface Command WARMUP Lake Shore www lakeshore com CRYOTRONICS 90 CHAPTER 5 Advanced Operation 5 5 2 Warm Up Control 5 6 Monitor Out 5 6 1 Monitor Units Model 350 Temperature Controller The Warm Up Control parameter determines what happens when the control set point is reached The options are m Auto Off once the Heater Range is set to on the Warm Up Percentage voltage is applied to the output section 5 5
187. he standard event summary bit through the enable register FIGURE 6 2 The Standard Event Status Enable command ESE programs the enable register and the query command ESE reads it ESR reads and clears the Standard Event Status Register The used bits of the Standard Event Register are described as follows m Power On PON Bit 7 this bit is set to indicate an instrument off on transition m Command Error CME Bit 5 this bit is set ifa command error has been detected since the last reading This means that the instrument could not interpret the command due to a syntax error an unrecognized header unrecognized termina tors or an unsupported command m Execution Error EXE Bit 4 this bit is set ifan execution error has been detected This occurs when the instrument is instructed to do something not within its capabilities m Query Error QYE Bit 2 this bit indicates a query error It occurs rarely and involves loss of data because the output queue is full m Operation Complete OPC Bit 0 when OPC is sent this bit will be set when the instrument has completed all pending operations The operation of this bit is not related to the OPC command which is a separate interface feature section 6 2 6 6 Lake Shore www lakeshore com CRYOTRONICS 112 CHAPTER 6 Computer Interface Operation Model 350 Temperature Controller Standard event Status register ESR ESR reads and clears the register
188. he self heating is accurately known then higher excitations with the reading adjusted for self heating may be better As previously stated another important trade off is instrument measurement noise In TABLE 2 1 instrument noise is not a dominate factor in the total uncertainty but is a factor in temperature stability Many times the speed of measurement is important and long averages are impractical therefore if keeping the temperature constant is more important than knowing the exact temperature then higher excitation currents may be best for a particular experiment Increasing signal to noise can also be import ant when dealing with other sources of noise such as cooling system noise sensor thermal noise vibration noise and induced electrical noise Lake Shore www lakeshore com CRYOTRONICS 28 CHAPTER 2 Cooling System Design and Temperature Control 2 8 Temperature Sensor Selection 2 8 1 Temperature Range 2 8 2 Sensor Sensitivity 2 8 3 Environmental Conditions 2 8 4 Measurement Accuracy Model 350 Temperature Controller This section attempts to answer some ofthe basic questions concerning temperature sensor selection Additional useful information on temperature sensor selection is available in the Lake Shore Temperature Measurement and Control Catalog The cat alog has a large reference section that includes sensor characteristics and sensor selection criteria You must consider several important sensor
189. her the heater output displays in current or power Valid entries 1 current 2 power HTRSET 1 1 2 0 1 term Heater output 1 will use the 25 O heater setting hasa maximum current of 1A the maximum user current is set to O A because it is not going to be used since a discrete value has been chosen and the heater output will be displayed in units of current lt max current gt max user current current power Heater Setup Query HTRSET output term n output Specifies which heater output to query 1 or 2 htr resistance gt lt max current gt lt max user current current power term n n n nnn n Heater Status Query HTRST lt output gt term n output error code term n error code Heater error code O no error 1 heater open load 2 heater short for output 1 or heater compliance for output 2 Error condition is cleared upon querying the heater status except for the heater com pliance error for output 2 which does not latch querying the heater status will also clearthe front panel error message for heater open or heater short error messages Specifies which heater output to query 1 or 2 IEEE 488 Interface Parameter Command IEEE address term nn address Specifies the IEEE address 1 30 Address O and 31 are reserved IEEE 4 term after receipt of the current terminator the instrument responds to address 4 IEEE 488 Interface Parameter Query IEEE
190. here fore a surface can be heated or cooled using a bipolar temperature control device For these types of bipolar devices the Model 350 features a bipolar control mode In this mode the Model 350 is configured to drive these devices to control temperature using Outputs 3 and 4 Refer to section 2 17 for more information about thermoelec tric devices To use Outputs 3 and 4 for bipolar control set the polarity to Bipolar The Closed Loop PID control mode can then be used to control a thermoelectric device providing a control output of 10 V to 10 V Refer to section 2 11 for information on thermoelec tric devices Referto section 3 6 5 4 for information on scaling the output for voltages less than 10 V Menu Navigation Output Setup Output 3 or 4 Polarity Bipolar Interface Command ANALOG Warm Up Supply mode is designed for controlling an external power supply used for rapidly increasing the temperature in the controlled system for example to bring a system to room temperature in order to change samples Refer to section 3 6 5 for information on using an external power supply for warm up supply mode The Control Input parameter determines which sensor is used for feedback in the Warm Up Supply mode Refer to section 4 5 1 5 for details on the Control Input parameter Once Warm Up Supply Mode is configured press Setpoint and set the desired tem perature then press Heater Range and set the range to On to activate the output T
191. hernet Function Connector Reading rate Software support Alarms Number Data source Settings Actuators Relays Number Contacts Contact rating Operation Connector Ambient temperature Power requirement Size Weight Approval 1 6 6 Interface 11 SH1 AH1 T5 L4 SR1 RL1 PPO DC1 DTO CO E1 To 10 rdg s on each input LabVIEW driver contact Lake Shore for availability Emulates a standard RS 232 serial port 57 600 B type USB connector To 10 rdg s on each input LabVIEW driver contact Lake Shore for availability TCP IP web interface curve handler configuration backup RJ 45 Top 10 rdg s on each input LabVIEW driver contact Lake Shore for availability 4 high and low for each input Temperature or sensor units Source high setpoint low setpoint deadband latching or non latching audible on off and visible on off Display annunciator beeper and relays 2 Normally open NO normally closed NC and common C 30VDCat3A Activate relays on high low or both alarms for any input or manual mode Detachable terminal block 15 C to 35 C at rated accuracy 5 C to 40 C at reduced accuracy 100 120 220 240 VAC 10 50 or 60 Hz 220 VA 435mm W x 89 mm H x 368 mm D 17 in x 3 5 in x 14 5 in full rack 7 6 kg 16 8 Ib CE mark contact Lake Shore for availability Lake Shore www lakeshore com CRYOTRONICS 12 CHAPTER 1 Introduction 1 7 Safety Summary and
192. hernetConfiguration 123 communicate with outside networks and by definition Auto IP only works on link local networks A disadvantage of Auto IP is the limitation of only working with a link local network which cannot connect to other networks including the internet Another disadvantage lies in the fact that an Auto IP assigned address will not be pre served through a device reconfiguration such as a power cycle To use Auto IP to automatically configure a link local IP address and subnet mask set the DHCP parameter to Off then set the Auto IP parameterto On By default the Auto IP feature ofthe Model 350 is Off Menu Navigation Interface Modify IP Config gt Auto P Off or On Static IP Static IP is a method of manually configuring the IP address subnet mask and gateway of Ethernet enabled devices When using the Static IP method the IP address subnet mask and gateway must be configured appropriately for the con nected network or for the connected PC in order to establish connection to the net work A major advantage to the Static IP method is that the IP address will not change during device reconfiguration power cycle Disadvantages of using the Static IP method include the requirement of knowing how your network is config ured in orderto choose the correct configuration parameters The Static IP method is always enabled and therefore will defaultto this method when both automatic configuration methods DHCP and Au
193. hore maintenance repair or calibra tion b fuses software power surges lightning and non recharge able batteries c software interfacing parts or other supplies not furnished by Lake Shore d unauthorized modification or misuse e operation outside ofthe published specifications f improper site preparation or site maintenance g natural disasters such as flood fire wind or earthquake or h damage during shipment other than original shipment to you if shipped through a Lake Shore carrier 6 This limited warranty does not cover a regularly scheduled or ordi nary and expected recalibrations of the Product b accessories to the Product such as probe tips and cables holders wire grease varnish feed throughs etc c consumables used in conjunction with the Product such as probe tips and cables probe holders sample tails rods and holders ceramic putty for mounting samples Hall sample cards Hall sample enclosures etc or d non Lake Shore branded Products that are integrated with the Product 7 To the extent allowed by applicable law this limited warranty is the only warranty applicable to the Product and replaces all other war ranties or conditions express or implied including but not limited to the implied warranties or conditions of merchantability and fitness for a particular purpose Specifically except as provided herein Model 350 Temperature Controller LakeShore undertakes no responsibi
194. hort inputs when not in use 3 5 9 1 Sensor Input Terminals Attach sensor leads to the screws on the off white ceramic terminal blocks Sensor connection is important when using thermocouples because the measured signal is small Many measurement errors can be avoided with proper sensor installation The block has two thermocouple inputs and each input has two screw terminals one pos itive one negative See FIGURE 3 8 Lake Shore www lakeshore com CRYOTRONICS 52 CHAPTER 3 Installation 3 6 Heater Output Setup 3 6 1 Heater Output Description Model 350 Temperature Controller Remove all insulation then tighten the screws on the thermocouple wires Keep the ceramic terminal blocks away from heat sources including sunlight and shield them from fans or room drafts INPUTC INPUT D FIGURE 3 8 Thermocouple input definition and common connector polarities inputs shown shorted 3 5 9 2 Thermocouple Installation Thermocouples are commonly used in high temperature applications Cryogenic use of thermocouples offers some unique challenges A general installation guideline is provided in section 2 10 Considerthe following when using thermocouples at low temperatures m Thermocouple wire is generally more thermally conductive than other sensor lead wire Smaller gauge wire and more thermal anchoring may be needed to prevent leads from heating the sample m Attaching lead wires and passing them through vacuum tight conn
195. ice versa but it does not allow manipulation of curve data and only works using the Ethernet interface Refer to section 6 4 4 for details on connecting to the web interface and opening the embedded Curve Handler application This section highlights some of the important elements of proper sensor installation For more detailed information Lake Shore sensors are shipped with installation instructions that cover that specific sensor type and package The Lake Shore Tem perature Measurement and Control Catalog includes an installation section as well To further help you properly install sensors Lake Shore offers a line of cryogenic accessories Many ofthe materials discussed are available through Lake Shore and can be ordered with sensors or instruments 2 10 1 Mounting Materials 2 10 2 Sensor Location 2 10 3 Thermal Conductivity 2 10 4 Contact Area 2 10 5 Contact Pressure 2 10 1 Mounting Materials 31 Choosing appropriate mounting materials is very important in a cryogenic environ ment The high vacuum used to insulate cryostats is one consideration Materials used in these applications should have a low vapor pressure so they do not evaporate or out gas and spoil the vacuum insulation Metals and ceramics do not have this problem but greases and varnishes must be checked Another consideration is the wide extremes in temperature most sensors are exposed to The linear expansion coefficient of materials becomes important when te
196. if an output is in the Off mode and does not apply to an output in Monitor Out mode An output in Monitor Out mode is always on Heater Range Query RANGE lt output gt term n lt output gt Specifies which output to query 1 4 lt range gt term n refer to command for description Input Reading Status Query RDGST lt input gt term a lt input gt Specifies which input to query A D D1 D5 for 3062 option status bit weighting term nnn The integer returned represents the sum ofthe bit weighting ofthe input status flag bits A 000 response indicates a valid reading is present Bit Bit Weighting Status Indicator 0 1 invalid reading 4 16 temp underrange 5 32 temp overrange 6 64 sensorunits zero 7 128 sensor units overrange Relay Control Parameter Command RELAY relay number gt lt mode gt lt input alarm gt lt alarm type gt term n n a n relay number Specifies which relay to configure 1 or 2 mode Specifies relay mode O Off 1 On 2 Alarms input alarm Specifies which input alarm activates the relay when the relay is in alarm mode A D D1 D5 for 3062 option alarm type Specifies the input alarm type that activates the relay when the relay is in alarm mode 0 Low alarm 1 High Alarm 2 Both Alarms RELAY 1 2 B O term relay 1 activates when Input B low alarm activates Relay Control Parameter Query RELAY relay number term n relay number Sp
197. imum temperature for a zone isthe upper boundary for the previous zone and O K is the starting point for the first zone When Zone tuning is on each time the setpoint changes appropriate control param eters are chosen automatically Zone tuning works best when used in conjunction with setpoint ramping section 4 5 1 5 7 You can determine control parameters manually or you can use the Autotune feature Autotune is a good way to determine a set of tuning parameters for the control sys tem that can then be entered as zones section 2 15 Athermoelectric device sometimes referred to as a Peltier device ora solid state heat pump is a device that takes advantage ofthe Peltier effect When a DC current is applied to the device heat is transferred from one side of the device to the other Heat can betransferred in either direction by reversing the polarity ofthe current Thermo electric devices are well suited for controlling temperatures near room temperature since they have both heating and cooling capabilities Since thermoelectric devices are solid state they are free ofthe mechanical vibrations associated with mechanical coolers Some thermoelectric coolers in a stacked configuration are capable of cool ing devices down to cryogenic temperatures about 100 K These are often used to cool and maintain the temperatures of charge coupled device CCD sensors Since thermoelectric devices are capable of both heating and cooling they require
198. in non latching operation With the high alarm setpointat 100 K and the dead band at 5 K the high alarm triggers when sensor input temperature increases to 100 K and it will not deactivate until temperature drops to 95 K In addition the same 5 K dead band is applied to the low alarm setpoint as well High alarm deactivated High alarm activated x High alarm setpoint 100 K Temperature reading Alarm latching off Deadband 5K 55K Low alarm setpoint 50K Low alarm activated M di Low alarm deactivated FIGURE 5 5 Dead band example To setup an alarm enter the Alarm Setup menu by pressing the Alarm key If a latching alarm has been activated you will be prompted with a Reset Alarm message Select No to enter the Alarm Setup menu Menu Navigation Alarm lnput A B C D gt Latching Off On Alarm Input A B C D Deadband see note below Low and High Setpoint limits are determined by the Preferred Units of the associated sensor input Default Latching Off Deadband 1 0000 K Interface Command ALARM Lake Shore www lakeshore com CRYOTRONICS 94 CHAPTER 5 Advanced Operation 5 7 2 Relays There are two relays on the Model 350 numbered 1 and 2 They are most commonly thought of as alarm relays but they may be manually controlled also Relay assign ments are configurable as shown in FIGURE 5 6 Two relays can be used with one sen sor input for independen
199. ination of sensor readings control setpoints and heater output data from the Model 350 A basic user interface is also provided for changing control parameters on the fly while acquiring data allowing many basic experiments to be performed without ever having to write any custom software Log files are stored in the Microsoft Excel xls format for easy data manipulation Free utilities are avail able online for converting xls files to comma separated plain text files csv if Micro soft Excel is not available 12 I u n eder Model 350 Temperature Controller 3900004 Lco co modnm File Log Chartt Help point 389 of 65000 Log Fike C isers justin_fichtner og x6 te ores ose rn vx ost eno g 7 10 Yi Command Line Motes Control Command ee Log File ain temer Documents og xi oes N EA Cart Orfy Do et log w fe vo J wera ton we 7 rons Kaian wor hatt me 80 Fato Kn 6 ws J Sequi x v Sepon 2 17 es LPN An seyor 115225 T E Model 350 Temperature Controller SN 350000A lma 13 1 s Number of Data Points te Log 120 41 14 Er ECEE 1 59 30 2295 13 50 40 135045 13595 135955 14004X Time FIGURE 6 11 Embedded chart recorder interface 6 5 4 1 Configuration Panel The configuration panel is located to the right of the chart and consists of items 12 through 17 in the screenshot above It is used to configure the charting and logging fun
200. ing and Shielding The capacitance input uses the same 6 pin din connector as the standard inputs and the same pins for current excitation and voltage feedback Cable capacitance in lon ger cables can cause large sensor reading errors if proper guarding and shielding methods are not applied To address this problem a driven guard is provided on pin 6 anda shield pin is provided on pin 3 The guard pin should be connected to a foil shield that surrounds a single twisted pair of wires used for I and V The shield pin on pin 3 should be connected to a foil shield that surrounds a single twisted pair of wires used for l and V See FIGURE 3 7 This wiring scheme must be applied to ensure proper sensor readings using the Model 3061 capacitance option Guard V Cs Shield FIGURE 3 7 Capacitance Input shield and gard The 3 496 kHz excitation of the option card can interfere with the sensitive DC measure ments of the standard inputs Tightly twist the lead wires of each sensor and separate them from the leads from the other sensor Test any system for sensor interference before it is permanently sealed The information in this section is for a Model 350 configured with thermocouple sen sor inputs Thermocouple inputs are not installed on the standard Model 350 but can be added by purchasing the Model 3060 dual thermocouple input option Refer to section 17 for installation of the Model 3060 Do notleave thermocouple inputs unconnected S
201. ion Model 350 Temperature Controller 5 9 1 2 Add a New Breakpoint Pair The last breakpoint of a curve is signified by the first pairthat contains a O value for both the temperature and sensor portions Curves are limited to 200 breakpoint pairs so if 200 pairs already exist then the 200th pair will be the last pair in the list To add a new breakpoint pairto a curve that has less than 200 pairs scroll to the end ofthe listand editthe O value pair by following the procedure for editing a breakpoint pair in section 5 9 1 1 If the curve still contains less than 200 pairs a new O value breakpoint will be added to the end ofthe list for entering another new breakpoint pair Menu Navigation Curve Entry Edit Curve gt 21 59 Curve Points 1 200 Interface Command CRVPT 5 9 1 3 Delete a Breakpoint Pair To delete a breakpoint pair scroll to the desired breakpoint number then enter a O value for both the sensor and temperature values by following the procedure for edit ing a breakpoint pair in section 5 9 1 1 If you are not entering O for both sensor and temperature values then entering new val ues over an existing breakpoint pair will replace that pair with the new value when you press Enter After editing adding or deleting all desired breakpoint pairs press Escape Exit Menu while the highlight is on a breakpoint number All breakpoint pair changes additions and deletions will be saved when exiting the menu When curve e
202. ir effect More specific installation instructions are given in Chapter 3 Noise from the environment is typically classified as either electric field E field or magnetic field H field E field noise capacitively couples into measurement leads or the sensor being measured Voltage is induced on the leads as if the noise source and lead are two halves of a capacitor The amount of coupling is related to the voltage change at the source the common area between source and receiver length of lead and dielectricO between them distance in air A cable shield is the first line of defense against E field noise Lake Shore www lakeshore com CRYOTRONICS 22 CHAPTER 2 Cooling System Design and Temperature Control 2 5 2 Ground Loop Noise 2 5 3 Analog Circuit Noise 2 5 4 Digital Circuit Noise Model 350 Temperature Controller No measurement cable of any length should be run from the Model 350 without a shield The shield provides a low impedance path to measurement common that prevents the voltage change at the source from being seen at the measurement leads H field noise inductively couples into measurement leads or other conductive loops Current is induced in the lead as if the noise source and lead are two halves of a trans former The amount of coupling is related to the field change from the source and the loop area Tightly twisted leads inside the shielded cable reduce the total loop area and minimize the effect of H fiel
203. ise and transmit it through line cords and interface cables Isolation in the Model 350 separates the measurement circuits from interface circuits but com puters must still be treated carefully during installation of a system 2 5 5 Resistor Thermal Noise 2 5 6 Vibration Noise 2 6 Measurement Error 2 6 1 Warm Up and Temperature Drift 2 6 2 Sensor Installation 2 6 3 Sensor Self Heating and Thermal Resistance 2 5 5 ResistorThermal Noise 23 Thermal noise or Johnson noise is the most common noise associated with resistors This noise is present in all resistors is independent of excitation and has a flat fre quency spectrum The equation for Johnson noise is often expressed as Vnoise AkTRAf 12 where Vnoise is the RMS noise voltage k is Boltzmann s constant 1 38 x 10 23 J K T is temperature in Kelvin and Af is the noise bandwidth in Hz Some considerations when using the equation peak to peak noise will be within 5 times RMS noise more than 99 of the time Af can be calculated several ways and a common method is 1 2 fagqp where f3gy is the 3 dB bandwidth of the dominant low pass filter in the measuring circuit As a practical example the noise voltage of a 100 kO resistor at room temperature using a 1 second filter is approximately 16 nV RMS or 80 nV PP When the resistor is cooled the thermal noise drops accordingly Thermal noise is normally the biggest noise source in higher value resistors being mea sured at r
204. isolated m Place ESD sensitive devices and assemblies removed from a unit on a conductive work surface or in a conductive container An operator inserting or removing a device or assembly from a container must maintain contact with a conductive portion ofthe container Use only plastic bags approved for storage of ESD material m Donothandle ESD sensitive devices unnecessarily or remove them from the packages until they are actually used or tested Follow this procedure to remove the top enclosure The enclosure top remove and replace procedure iffor installing an input option card To avoid potentially lethal shocks turn off the controller and disconnect it from AC power before performing these procedures The components on this board are electrostatic discharge sensitive ESDS devices Follow ESD procedures in section 8 11 to avoid inducing an electrostatic discharge ESD into the device 1 Turn the Model 350 power switch Off Unplug the power cord from the wall out let then from the instrument 2 Stand the unit on its face Use a 5 64 in hex driver to remove the four screws on both sides of the top cover Loosen the two rear bottom screws FIGURE 8 10 Remove g o Remove rear rear plastic 1 bottom bezel cover screw Loosen unshown bottom rear side cover Remove top screws cover screws both sides To remove Remove top top cover oid slide it to the rear both sides onthe tracks FIGURE 8 10 Co
205. ity is provided for uploading temperature curve files to the Model 350 The utility is also capable of reading curves from the Model 350 and writing them to a file forstorage or manipulation in a third party pro gram The Embedded Curve Handler supports standard Lake Shore temperature curve files in the 4340 file format and the Microsoft Excel XLS Excel 97 2003 file format Curve files are provided with calibrated sensors purchased from Lake Shore in the 340 file format To read a temperature curve from a file click Read from File Select a properly format ted temperature curve 340 or XLS file using the Open Browser dialog box The curve will be loaded into the program and the curve points and graph will be dis played To read a temperature curve from the Model 350 click Read from Instrument The Read Curve from Instrument dialog box appears Select a curve from the drop down box and click OK The curve will be loaded into the program and the curve points and graph will be displayed Once a curve is loaded into the Embedded Curve Handler using either the Read from File or Read from Instrument buttons the loaded curve can be stored eitherto a user curve location 21 to 59 in the Model 350 orto a file To store the curve to a user curve location in the Model 350 click Write to Instru ment The Write Curve to Instrument dialog box appears Select a user curve location to write the loaded temperature curve to and clic
206. k OK To write the currently loaded curve to a file click Write to File A Save Browser dialog box appears First use the Files of Type drop down box to select the file format in which to save the curve Then choose a directory and a file name and click Save The 340 file format is an ASCII text file which can be read and altered using a stan dard ASCII text editor Care must be taken when altering the 340 text files to ensure that all ofthe values are stored in the same position in the file asthe original values using the same number of digits To alter curve files itis recommended to use the XLS file format which can be altered using Microsoft Excel If using formulas to alter curves you must copy the results of the formulas and paste them back into the origi nal cells of the breakpoint values The Embedded Curve Handler cannot interpret formulas in cells In most versions of Excel this can be done by copying the formula results then pasting them in the appropriate cells using the Paste Special command and selecting Paste Values Refer to the appropriate Microsoft Excel documentation for details on the Paste Special operation 6 5 2 Ethernet Firmware Updater 6 5 2 EthernetFirmwareUpdater 131 The Embedded Curve Handler cannot read files in the Microsoft Excel XLSX Excel 2007 or newer format When saving files from Excel be sure to save them in the XLS Excel 97 2003 format so that the file can be read using the
207. ke Shore www lakeshore com CRYOTRONICS 36 CHAPTER 2 Cooling System Design and Temperature Control 2 11 4 Heater Wiring 2 12 Consideration for Good Control 2 12 1 Thermal Conductivity 2 12 2 Thermal Lag 2 12 3 Two Sensor Approach 2 12 4 Thermal Mass Model 350 Temperature Controller Foil heaters are thin layers of resistive material adhered to or screened onto electri cally insulating sheets There are a variety of shapes and sizes The proper size heater can evenly heat a flat surface or around a round load The entire active area should be in good thermal contact with the load not only for maximum heating effect but to keep spots in the heater from over heating and burning out When wiring inside a vacuum shroud we recommend using 30 AWG copper wire for heater leads Too much heat can transfer in when larger wire is used Thermal anchor ing similarto that used forthe sensor leads should be included so that any heat transfer does not warm the load when the heater is not running The lead wires should be twisted to minimize noise coupling between the heater and other leads in the system When wiring outside the vacuum shroud you can use larger gage copper and twisting is still recommended Most ofthe techniques discussed in section 2 10 and section 2 11 to improve cryo genic temperature accuracy apply to control as well There is an obvious exception in sensor location A compromise is suggested below in section
208. l P iecceep prre ERE DI ERR YA RI N E UTR REA NR 37 2113 2 Integral es usine tete Eee S eC este pe ondediat b EENA 37 213 3 Derivative D ic ort ectpt ee er E Ebr Ee HER D YER RUE 38 213 4 Man al QUEDUt e rore tedoet e EE ON RLUDSPRP EIN DNUR 38 2 14 Man al T nlrig rnm er rh a RERXCRV ERI Or E RE RLP OI RR ECTS 40 214 1 Setting Heater RANEE nireset ea RR E QUDHE SN Ra xvi ERE NU MAN 40 214 2 Tuning Proportional esris rires iransi scinn Rer REEERE ADNET 40 Chapter 3 Installation Chapter 4 Operation 21433 Tuning Integral rsrsrsrs riist eren IR YE e ERR ER ER SOR Ya FE PERRA Rn 41 2 14 4 Tuning DerivatlVes uie eet erp een REN RE RRQUU MERI UU RER ES 42 2 15 AULOCUNING s2tectiiaietts rient eU PUELERRBU UN PREMO UE IB CENT ARE TER Rd 42 2 16 Zone TU MING issue teet E px dace wanes ee RE Ae eae dun bti VA tace 43 237 Thermoelectric Devices oret xg pec RR RR TORRE RR 43 3 1 General M S 45 3 2 Inspection and Unpacking 6 cece cece ee 45 3 3 Rear PanelDefImtioniss coe YN Ra RE X RR Re Er pei uen HE quat 45 3 4 LineInputAssembly 2 0 0 0 cece cece ris Ihe eee eee 46 3 4 1 line Voltage i cosas eee reete Exe canines EEEE EEEN RE E CREER 46 3 4 2 Line Fuse and Fuse Holder sssssssssssssssssssssssssss e 46 3 4 3 POWER COM i eer pee eO PE Qu aene Cue ARE ESQ Es 47 3 44 POWeLSWIEC zit re RET S EAEE KAE RS ERI PEE e TORY E 47 3 5 Diode Resistor SensorInputs isse nee 47 3 5
209. l speaker will beep when an alarm condition occurs Valid entries O off 1 on visible Specifies ifthe Alarm LED on the instrument front panel will blink when an alarm condition occurs Valid entries O off 1 2 on Configures the alarm parameters for an input ALARM A O term turns off alarm checking for Input A ALARM B 1 270 0 0 0 1 1 1 term turns on alarm checking for input B activates high alarm if kelvin reading is over 270 and latches the alarm when kelvin reading falls below 270 Alarm condition will cause instrument to beep and the front panel Alarm LED to blink ALARM Input Format Returned Format ALARMST Input Format Returned Format ALMRST Input Remarks ANALOG Input Format Example Remarks 6 6 1 InterfaceCommands 141 Input Alarm Parameter Query ALARM input term a input A D D1 D5 for 3062 option lt off on gt lt high value gt lt low value gt lt deadband gt lt latch enable gt lt audible gt lt visible gt term n tnnnannn tnnnnnn nnnnnn n n n refer to command for description Input Alarm Status Query ALARMST input term a lt input gt A D D1 D5 for 3062 option high state gt lt low state gt term n n lt high state gt 0 Off 1 On lt low state gt O0 Off 1 On Reset Alarm Status Command ALMRST term Clears both the high and low status of all alarms including latching alarms Monitor Out Parameter Command ANALOG
210. led Diode PTC RTD Platinum NTC RTD Cernox Default Diode Interface Command INTYPE 4 4 7 1 Type and Range Selection The 4 channel scanner option can be configured as either diode PTC RTD or NTC RTD Autorange will be on by default whenever the Sensor Type parameter is set to PTC RTD or NTC RTD To manually select the resistance range set the Autorange parameter to Off then use the Range parameter to select the desired range Menu Navigation Input Setup Input D2 D3 D4 or DS Autorange gt Off or On Input Setup Input D2 D3 D4 or D5 Range gt See TABLE 4 9 Default On Interface Command INTYPE 4 4 8 Curve Selection 4 4 8 CurveSelection 71 DVEHEDII Sensor Type Range Maximum Sensor Power Settings Sensor Excitation Diode 2 5 V Silicon 25 pW at 10 pA excitation 10 pA 1mA 10 V GaAIAs 100 pW at 10 p excitation 10 pA 1mA 100 10 pW 300 30uW 100 0 100 pW TAS 300 Q 300 pW 1mA 1kQ 1mW 3kQ 3mW 10kQ 10 mW 100 10 pW 1mA 300 2 7 uW 300 pA 1000 1uW 100 pA 3000 270 nW 30 pA NTCRID 1kQ 100 nw 10 pA Cernox 3kO0 27nW 3yA 10kQ 10nW 1pA 30kQ 2 7 nW 300 nA 100 kQ 1nW 100 nA TABLE 4 9 Model 3062 4 channel scanner option range and sensor power 4 4 7 2 Update Rate The update rate for the scanned input channels is dependent on the number of chan nels enabled and how many enabled channels are configured for 100 KQ NTC RTD The
211. lf heating could become a significant part ofthe overall accuracy Calculations like this are diffi cult to do for two reasons first manufactures do not always publish specifications on thermal resistance and second the actual thermal resistance is very dependent on installation An explanation of how to calculate thermal resistance of a temperature sensor is given in the Lake Shore Temperature Measurement and Control Catalog Appendix A With an estimate of thermal resistance the effect of increased excitation current can be predicted If self heating behavior does not match the prediction noise power may be high enough to heat the sensor Measurement leads in cryogenic systems routinely have resistance of tens or even hundreds of ohms Lead wire is chosen for its thermal properties first and electrical resistance is a secondary consideration The Model 350 measurement circuits can tolerate significant lead resistance without measurement error This lead resistance will give a measurement error that is small compared to the specified accuracy on the sensor range and in most cases the error is not measurable Any measurement must be optimized to provide the best practical result and trade offs must be made to favor the most important measurement characteristics Some of the common trade offs of low temperature measurement are described below Even after leads are properly heat sunk and noise is effectively shielded there can bea temperature
212. lgorithm called PID control The control equation for the PID algorithm has three variable terms proportional P integral I and derivative D See FIGURE 2 4 Changing these variables for best control of a system is called tuning The PID equation in the Model 350 is Heater Output P e If e dt D v where the error e is defined as e Setpoint Feedback Reading Proportional is discussed in section 2 13 1 Integral is discussed in section 2 13 2 Derivative is discussed in section 2 13 3 Finally the manual heater output is dis cussed in section 2 13 4 The Proportional term also called gain must have a value greater than 0 for the con trol loop to operate The value ofthe proportional term is multiplied by the error e which is defined asthe difference between the setpoint and feedback temperatures to generate the proportional contribution to the output Output P Pe If propor tional is acting alone with no integral there must always be an error or the output will go to 0 A great deal must be known about the load sensor and controller to com pute a proportional setting P Most often the proportional setting is determined by trial and error The proportional setting is part of the overall control loop gain and so are the heater range and cooling power The proportional setting will need to change if either ofthese change In the control loop the integral term also called reset looks at error overtime t
213. lick Cancel 7 Right click on Lake Shore Model 350 and click Update Driver Software 8 Click Browse my computer for driver software 9 Click Browse and select the location of the extracted driver 10 Ensure the Include subfolders check box is selected and click Next 11 When the driver finishes installing a confirmation message stating Windows has successfully updated your driver software should appear Click Close to com plete the installation o For Windows XP 1 Connectthe USB cable from the Model 350 to the computer 2 Turn on the Model 350 3 The Found New Hardware wizard should appear If the Found New Hardware wizard does not appear the following procedure can be used to open the Hard ware Update wizard which can be used instead a OpenDevice Manager Use this procedure to open the Device Manager m Right clickon My Computer and then click Properties This will open the System Properties dialog m Clickthe Hardware tab and then click Device Manager b Click View and ensure the Devices by Type check box is selected 6 3 4 Communication 6 3 4 Communication 119 c Inthemain window of Device Manager locate the Ports COM amp LPT device type In many instances this will be between the Network adapt ers and Processors items If the Ports COM amp LPT item is not already expanded click the icon Lake Shore Model 350 should appear indented underneath Ports COM amp LPT If itis not displayed as
214. lity csse 134 6 544 Utilities PANE 2 neot ep ete tides nadie tte a Edda 134 6 5 4 5 MENU errenneren ene a E Rp DIEA ELODITEEN EUROS ween eens 135 6 546 InfortiatlOhissus see redet x TORRE dus Ra epe i EU 135 6 6 COMMANG SUMMALY sese seestex te a e ERR ER TI ERIS RA COURIER T 136 6 6 1 Interface Commands eee cece eect esee 138 Chapter 7 Vue PT A E EEEE 159 Options and TAS Oa lE E EEE E A T E AE T 159 Accessories 73 gt OPUONS sects EU 159 7 4 AGCESSOMES sp csciarteasetnstutin tres ts eduebete oe ant DURER dber tpe den vor er FER Gs 159 7 5 Field Installation 5 o ont Rr Ret RE RpepRIVPda E EEEE PERO DIS 161 Chapter 8 CMMES TII MORE ETT DET 165 Service 8 2 USB Tro bleslioOtlg ues see npe tr pe ete ES E E EE ETE EEn Randa 165 8 2 1 New Installation ssssssssssssssssssss e e eene 165 8 2 2 Existing Installation No Longer Working cssssss 165 8 2 3 Intermittent Lockups ssssssssssssssssss e eme emen 165 Model 350 Temperature Controller vii 8 3 IEEE Interface Troubleshooting ccc ceee cece e eee ee eee s a ETTE 166 8 3 1 New Installation 2 52 rrr ER RR ganna P3 pr AR SUPR RIPE 166 8 3 2 Existing Installation No Longer Working sss 166 8 3 3 Intermittent LOCKUDS isse eres Rate ee exe ERR A NEAR 166 84 Fuse Drawer forconin oriin EEn ee vea tex OE Rates eh aisi eme eaa des iei dn 166 8 5 Line Voltage Selection Ji ees tor eter to to ebria a n pP pe Fx cule Pega
215. lity that the products will be fit forany particular purpose for which you may be buying the Products Any implied warranty is limited in duration to the warranty period No oral or written information or advice given by the Company its Agents or Employees shall create a warranty or in any way increase the scope of this limited warranty Some countries states or provinces do not allow limitations on an implied warranty so the above limita tion or exclusion might not apply to you This warranty gives you spe cific legal rights and you might also have other rights that vary from country to country state to state or province to province 8 Further with regard to the United Nations Convention for Interna tional Sale of Goods CISC if CISG is found to apply in relation to this agreement which is specifically disclaimed by Lake Shore then this limited warranty excludes warranties that a the Product is fit for the purpose for which goods of the same description would ordinarily be used b the Product is fit for any particular purpose expressly or impliedly made known to Lake Shore at the time of the conclusion of the contract c the Product is contained or packaged in a manner usual for such goods or in a manner adequate to preserve and protect such goods where it is shipped by someone other than a carrier hired by Lake Shore 9 Lake Shore disclaims any warranties of technological value or of non infringement with respect to the Produc
216. lling a confirmation message stating Windows has successfully updated your driver software should appear Click Close to com plete the installation For Windows XP 1 Insertthe CD into the computer 2 Connectthe USB cable from the Model 350 to the computer 3 Turn on the Model 350 4 When the Found New Hardware wizard appears select No not at this time and click Next Select Install the software automatically recommended and click Next 6 The Found New Hardware wizard should automatically search the CD and install the drivers 7 When the Found New Hardware Wizard finishes installing the drivers a message stating the wizard has finished installing the software for Lake Shore Model 350 Temperature Controller should appear Click Finish to complete the installation wo Communicating via the USB interface is done using message strings The message strings should be carefully formulated by the user program according to some simple rules to establish effective message flow control Lake Shore www lakeshore com CRYOTRONICS 120 CHAPTER 6 Computer Interface Operation 6 3 5 Message Flow Control Model 350 Temperature Controller 6 3 4 1 Character Format Acharacter is the smallest piece of information that can be transmitted by the inter face Each character is ten bits long and contains data bits bits for character timing and an error detection bit The instrument uses seven bits for data in the American S
217. longer offered by Lake Shore Instrument may not support the sensor over its entire range TABLE4 11 Sensor curves Once the input is configured section 4 4 you may choose a temperature curve Any standard or user curve that matches the format of the sensortype configured for a given input will be available underthe Curve parameter in the Input Setup menu for that input You are also given the choice of None When set to None front panel read ings configured for kelvin or Celsius will display the NOCURV message and the inter face will report O K and 273 15 C for KRDG and CRDG queries respectively Data points for standard curves are detailed in Appendix C Menu Navigation Input Setup nput A B C or D Curve Any curve of matching type 4 4 9 Filter The reading filter applies exponential smoothing to the sensor input readings If the filter is turned on fora sensor input all reading values for that input are filtered The filter is a running average so it does not change the update rate of an input Filtered readings are not used for control functions but they are used for all input features including Max Min The number offilter points determines filter bandwidth One filter point corresponds to one new reading on that input A larger number of points does more smoothing but also slows the instruments response to real changes in temperature The default number of filter points is 8 which settles to within six time constants
218. lookup to determine if a domain name is assigned for the Model 350 s configured IP address This will occur regardless of whether the domain name was configured dynamically using DDNS or manually by the network administrator The returned domain name will appear in the Actual Hostname parameter in the View IP Config submenu ofthe Interface Setup menu When using naming systems other than DNS the Model 350 cannot assign the Preferred Domain Name or retrieve the Actual Domain Name Menu Navigation The Preferred Domain name can only be entered using a computer interface NET command and viewed using the NET query Refer to section 6 6 1 for details on the NET command and query When the Ethernet interface is enabled two submenus become available Modify IP Config and View IP Config All configurable settings are available under the Modify IP Config submenu and the current state ofthe Ethernet configuration is detailed in the View IP Config submenu This is designed to eliminate confusion as to which are the configurable Static IP settings and which are the currently configured settings that could have been configured using any ofthe three configuration methods DHCP Auto IP or Static IP The method used for the currently established connection is shown in the LAN Status parameter ofthe View IP Confi submenu section 6 4 2 1 6 4 2 1 LAN Status The LAN Status parameter indicates the current status of the Ethernet configuration This r
219. lt output gt lt input gt lt units gt high value gt lt low value gt lt polarity gt term n njn znnnnn tnnnnn n lt output gt Unpowered analog output to configure 3 or 4 lt input gt Specifies which input to monitor O none 1 Input A 2 Input B 3 Input C 4 Input D 5 Input D2 6 Input D3 7 Input D4 8 Input D5 for 3062 option lt units gt Specifies the units on which to base the output voltage 1 kelvin 2 Celsius 3 sensor units lt high value gt If output mode is Monitor Out this parameter represents the data at which the Monitor Out reaches 100 output Entered in the units designated by the lt units gt parmeter Refer to OUTMODE command lt low value gt If output mode is Monitor Out this parameter represents the data at which the analog output reaches 100 output if bipolar or 0 output if positive only Entered in the units designated by the lt units gt parmeter polarity Specifies output voltage is O unipolar positive output only or 1 bipolar positive or negative output ANALOG 4 1 1 100 0 0 0 0 term sets output 4 to monitor Input A kelvin reading with 100 0 K at 100 output 10 0 V and 0 0 K at 0 output 0 0 V Use the OUTMODE command to set the output mode to Monitor Out The lt input gt parameter in the ANALOG command is the same as the lt input gt parameter in the OUT MODE command It is included in the ANALOG command for backward compatibility with previous Lake
220. lution Other displays Setpoint setting resolution Heater output display Heater output resolution Display annunciators LED annunciators Keypad Front panel features Closed loop PID PID zones warm up heater mode still heater ADR con trol manual output or monitor output Oto 10096 with 196 resolution Continuous control or auto off User selected Temperature or sensor units Input source top of scale bottom of scale or manual Variable DC voltage source 10 s 10V 16 bit 0 3 mV t2 5 mV 0 3 mV RMS 100 mA 1 W into 100 Q 100 Q short circuit protected Detachable terminal block 8 line by 40 character 240 x 64 pixel graphic LCD display module with LED backlight 1to8 K C V mV O Temperature sensor units max and min 2 rdg s 0 00001 from 0 to 9 999999 0 0001 from 10 to 99 99999 0 001 from 100 to 999 9999 0 01 above 1000 Sensor dependent to 6 digits Input name setpoint heater range heater output and PID Same as display resolution actual resolution is sensor dependent Numeric display in percent of full scale for power or current 0 01 Control input alarm tuning Remote Ethernet status alarm control outputs 27 key silicone elastomer keypad Front panel curve entry display contrast control and keypad lock out 1 6 6 Interface 1 6 7 General IEEE 488 2 Capabilities Reading rate Software support USB Function Baud Rate Connector Reading rate Software support Et
221. mal thermal impact or precise temperature control in high magnetic fields or depend able measurement in radiation environments the new Model 350 controller matched with Lake Shore s industry leading Cernox sensors provides a cryogenic solution that s demonstrably best in class The patented noise reduction input circuitry of the Model 350 is just one reason why this controller works so well for ultra low temperature ULT applications all the way down to 100 mK When combined with precision Cernox sensors this performance optimized design allows as little as 10 nA of excitation current to be used minimizing self heating effects and ensures best possible measurement accuracy throughout the entire temperature range This single instrument offers extraordinary capability and flexibility often eliminat ing the need for additional instrumentation in a refrigeration control system Its four input channels and four independent control outputs are configurable to support a broad range of I O requirements including the heaters and auxiliary devices typical of ULT refrigeration systems as well as other cryogenic sensor types like ruthenium oxide and platinum RTDs Standard computer interfaces enable remote communica tions control and coordination with other systems Lake Shore www lakeshore com CRYOTRONICS 2 CHAPTER 1 Introduction 1 2 Application Versatility 1 2 1 Four Standard Sensor Input Channels 1 2 2 Three Option
222. mand MNMXRST term Resets the minimum and maximum data for all inputs Remote Interface Mode Command MODE mode term n mode 0 local 1 remote 2 remote with local lockout MODE 2 term places the Model 350 into remote mode with local lockout Remote Interface Mode Query MODE term mode term n referto command for description Manual Output Command MOUT output value term n nnnnn term output Specifies output to configure 1 4 lt value gt Specifies value for manual output MOUT 1 22 45 term Output 1 manual output is 22 45 Manual output only applies to outputs in Closed Loop PID Zone or Open Loop modes Manual Output Query MOUT output term n output value t nnnnn term refer to command for description Specifies which output to query 1 4 Network Settings Command NET lt DHCP gt lt AUTO IP gt lt IP gt lt Sub Mask gt lt Gateway gt lt Pri DNS gt lt Sec DNS gt lt Pref Host gt lt Pref Domain gt lt Description gt term n n dd dd dd dd dd s 15 s 64 s 3 2 lt DHCP gt 0 DHCP off 1 DHCP on AUTO IP 0 Dynamically configured link local addressing Auto IP off 1 On IP IP address for static configuration Sub Mask gt Subnet mask for static configuration NET Input Returned Format NETID Input Returned Format Remarks OPST Input Returned Format Remarks 6 6 1 InterfaceCommands 151
223. mmand DISPFLD field input units term n n n lt field gt Specifies field display location to configure 1 8 lt input gt Specifies item to display in the field O None 1 Input A 2 Input B 3 Input C 4 Input D 5 Input D2 6 Input D3 7 Input D4 8 Input D5 for 3062 option lt units gt Valid entries 1 kelvin 2 Celsius 3 sensor units 4 minimum data and 5 maximum data DISPFLD 2 1 1 term displays kelvin reading for Input A in display field 2 when dis play mode is set to Custom This command only applies to the readings displayed in the Custom display mode All other display modes have predefined readings in predefined locations and will use the Preferred Units parameter to determine which units to display for each sensor input Refer to section 4 3 for details on display setup Custom Mode Display Field Query DISPFLD field term n field Specifies field display location to query 1 8 lt input gt lt units gt term n n refer to command for description DISPLAY Input Format Example Remarks DISPLAY Input Returned Format FILTER Input Format Example FILTER Input Format Returned Format HTR Input Format Returned Format Remarks 6 6 1 InterfaceCommands 145 Display Setup Command DISPLAY lt mode gt lt num fields gt lt output source term n n n mode Specifies display mode 0 Input A 1 Input B 2 Input C
224. mperature approach the setpoint 4 Adjustthe integral setting if necessary a Ifthe temperature does not stabilize and begins to oscillate around the setpoint the integral setting is too high and should be reduced by one half b Ifthetemperature is stable but never reaches the setpoint the integral setting is too low and should be doubled 5 Verify the integral setting by making a few small 2 K to 5 K changes in setpoint and watch the load temperature react Trial and error can help improve the integral setting by optimizing for experimental needs Faster integrals for example get to the setpoint more quickly at the expense of greater overshoot In most systems setpoint changes that raise the temperature act differently than changes that lower the temperature If it was not possible to measure the oscillation period ofthe load during proportional setting start with an integral setting of 20 If the load becomes unstable reduce the setting by half If the load is stable make a series of small two to five degree changes in the setpoint and watch the load react Continue to increase the integral setting until the desired response is achieved Lake Shore www lakeshore com CRYOTRONICS 42 CHAPTER 2 Cooling System Design and Temperature Control 2 14 4 Tuning Derivative 2 15 Autotuning Model 350 Temperature Controller If an experiment requires frequent changes in setpoint derivative should be consid ered See F
225. mperature changes are large Never try to permanently bond materials with linear expansion coefficients that dif fer by more than three Use a flexible mounting scheme orthe parts will break apart potentially damaging them The thermal expansion or contraction of rigid clamps or holders could crush fragile samples or sensors that do not have the same coefficient Thermal conductivity is a property of materials that can change with temperature Do not assume that a thermal anchor grease that works well at room temperature and above will do the same job at low temperatures Finding a good place to mount a sensor in an already crowded cryostat is never easy There are fewer problems if the entire load and sample holder are at the same tem perature Unfortunately this not the case in many systems Temperature gradients differences in temperature exist because there is seldom perfect balance between the cooling source and heat sources Even in a well controlled system unwanted heat sources like thermal radiation and heat conducting through mounting structures can cause gradients For best accuracy position sensors near the sample so that little or no heat flows between the sample and sensor This may not however be the best location for temperature control as discussed below The ability of heat to flow through a material is called thermal conductivity Good thermal conductivity is important in any part of a cryogenic system that is intended to be
226. ms requiring different configurations All instrument configura tion settings are exported or imported by the utility except for the setpoint and heater range network settings and web login settings These settings are ignored to preventthe outputs from unintentionally turning on and to prevent interrupting communication with the instrument To export the current configuration of the Model 350 to a file 1 Onthe Utilities page in the Model 350 embedded website click Export config FIGURE 6 8 2 IntheSaveFile dialog box select the location and file name to which you want to export the current instrument configuration Click Save The utility will export the current configuration from the Model 350 and save it to the specified file To import a saved configuration from a file to the Model 350 1 Onthe Utilities page in the Model 350 embedded website click Import config FIGURE 6 8 2 Inthe Save File dialog box select the file name from which you want to import the saved instrument configuration settings Click Open 3 Click Yes import settings in the confirmation box that appears The utility will read the configuration from the specified file and import itto the Model 350 6 5 4 Embedded Chart Recorder 6 5 4 Embedded Chart Recorder 133 The embedded chart recorder utility is provided to allow users to easily acquire and chart data from the Model 350 The chart recorder utility can simultaneously chart and log any comb
227. n large character format using the units assigned to the respective input s Input Units parameter When a Model 3062 Lake Shore www lakeshore com CRYOTRONICS 62 CHAPTER 4 Operation Model 350 Temperature Controller option is installed all eight sensor inputs and channels are displayed and the display mode can be configured as large or small When itis configured as large the input name is not shown and the sensor reading is displayed in large character format When it is configured as small the input name is shown and the sensor reading is dis played in the normal smaller character format Menu Navigation Display Setup Display Mode 4All Inputs Mode Interface Command DISPLAY 4 3 1 3 Input Display Modes An Input Display mode exists for each ofthe four sensor inputs on the Model 350 These modes are referenced as Input A Input B Input C and Input D inthe Display Mode parameter list Each of these modes provides detailed information relevant to the respective sensor input Bk I of Hed I MI FIGURE 4 4 Input display mode The top half ofthe display provides information related to the sensor input The input letter is displayed followed by the user assignable input name The sensor reading is displayed in large character format using the units assigned to the respective input s Input Units parameter The top half ofthe display also shows the maximum and the minimum sensor reading since the last Max Min reset
228. n section 6 3 3 1 through section 6 3 3 4 to download extract and install the driver using Windows 7 Vista and XP 6 3 3 3 1 Download the driver 1 Locate the Model 350 USB driver on the downloads page on the Lake Shore website 2 Right click on the USB driver download link and select save target link as 3 Savethe driverto a convenient place and take note as to where the driver was downloaded 6 3 3 3 2 Extract the driver The downloaded driver is in a ZIP compressed archive The driver must be extracted from this file Windows provides built in support for ZIP archives If this support is disabled a third party application such as WinZip or 7 Zip must be used For Windows 7 and Vista 1 Rightclickon the file and click extract all 2 AnExtract Compressed Zipped Folders dialog box will appear It is recom mended the default folder is not changed Take note ofthis folder location 3 Clickto clearthe Show extracted files when complete checkbox and click Extract For Windows XP 1 Right click on the file and click extract all 2 The Extraction wizard will appear Click Next Lake Shore www lakeshore com CRYOTRONICS 118 CHAPTER 6 Computer Interface Operation Model 350 Temperature Controller 3 Itisrecommended to keep the same default folder Take note of this folder loca tion and click Next 4 An Extraction complete message will be displayed Click to clear the Show extracted files checkb
229. n the Status Byte Register Reading all messages in the output buffer including any pending queries will clear the message available bit The bits of the Status Byte Registerare described as follows m Operation Summary OSB Bit 7 this bitis set when an enabled operation event has occurred m Request Service RQS Master Summary Status MSS Bit 6 this bitis set when a summary bit and the summary bit s corresponding enable bit in the Service Request Enable Register are set Once set the user may read and clearthe bit in two different ways which is why itis referred to as both the RQS and the MSS bit When this bit goes from low to high the Service Request hardware line on the bus is set this isthe RQS function ofthe bit section 6 2 6 3 In addition the status of the bit may be read with the STB query which returns the binary weighted sum of all bits in the Status Byte this is the MSS function ofthe bit Performing a serial poll will automatically clear the RQS function but it will not clear the MSS function A STB will read the status ofthe MSS bit along with all of the summary bits but also will not clear it To clear the MSS bit either clear the event register that set the summary bit or disable the summary bit in the Service Request Enable Register m Event Summary ESB Bit 5 this bit is set when an enabled standard event has occurred Lake Shore www lakeshore com CRYOTRONICS 114 CHAPTER 6 Computer I
230. nd International Electrotechnical Commission IEC safety standards Ventilation The instrument has ventilation holes in its side covers Do not block these holes when the instrument is operating Do Not Operate in an Explosive Atmosphere Do not operate the instrument in the presence of flammable gases or fumes Opera tion of any electrical instrument in such an environment constitutes a definite safety hazard Keep Away from Live Circuits Operating personnel must not remove instrument covers Refer component replace ment and internal adjustments to qualified maintenance personnel Do not replace components with power cable connected To avoid injuries always disconnect power and discharge circuits before touching them Do Not Substitute Parts or Modify Instrument Do not install substitute parts or perform any unauthorized modification to the instrument Return the instrument to an authorized Lake Shore Cryotronics Inc rep resentative for service and repairto ensure that safety features are maintained Cleaning Do not submerge instrument Clean only with a damp cloth and mild detergent Exte rior only O 2 A Direct current power line E Alternating current power line Alternating or direct current power line A Three phase alternating current power line Earth ground terminal AN Protective conductor terminal Frame or chassis terminal On supply Off supply FIGURE 1 3 Safety symbols 1 7 SafetySumm
231. nd repair instructions All equipment returns must be approved by a member ofthe Lake Shore Service Department The service engineer will use the information provided in the service request form and will issue an RMA This number is necessary for all returned equipment It must be clearly indicated on both the shipping carton s and any correspondence relating to the shipment Once the RMA has been approved you will receive appropriate documents and instructions for shipping the equipment to Lake Shore RMAs are valid for 60 days from issuance however we suggest that equipment needing repair be shipped to Lake Shore within 30 days after the RMA has been issued You will be contacted if we do not receive the equipment within 30 days after the RMA is issued The RMA will be cancelled if we do not receive the equipment after 60 days All shipments to Lake Shore are to be made prepaid by the customer Equipment serviced under warranty will be returned prepaid by Lake Shore Equipment serviced out of warranty will be returned FOB Lake Shore Lake Shore reserves the right to charge a restocking fee for items returned for exchange or reimbursement Lake Shore www lakeshore com CRYOTRONICS 178 CHAPTER 8 Service Model 350 Temperature Controller
232. ndard curve but in general these sensors do not provide the accuracy of a calibrated sensor For convenience the Model 350 has several standard curves included in firmware Lake Shore provides a software application called Curve Handler which makes loading temperature curves into the Model 350 a very simple process The program can copy curves from properly formatted files into the Model 350 user curve loca tions You can also use itto read curves from the Model 350 and save them to files Lake Shore calibrated sensors are provided with a CD containing all the proper for mats to load curves using the Curve Handler software program There are two versions of the Curve Handler application The fully featured version is a 32 bit Microsoft Windows application that must be installed on a Windows PC This version works with the IEEE 488 and USB computer interfaces on the Model 350 and allows you to manipulate the temperature curves directly in the pro gram window This version will also work with all existing Lake Shore temperature controller and temperature monitor instruments The Windows version of the Curve Handler application is available free of charge from the Lake Shore website at www lakeshore com The second version of Curve Handler is written in the Java programming language andis available through the Ethernet web interface on the Model 350 This version allows you to copy curves from files to the Model 350 and v
233. ne Registers are not latched Event registers Standard event status register ESR clears Standard Event uery the event register Query 8 Status Register Operation event register Send CLS CLS clears both registers Power on instrument Enable registers Write 0 to the ESE 0 clears Standard Event Standard Event Status Enable Register enable register Status Enable register Operation Event Enable Register Service Request Enable Register Poweron instrument Status byte There are no commands that directly clear the status byte as the bits are If bit 5 ESB of the status byte is non latching to clear individual summary bits clear the event register that set send ESR to read the corresponds to the summary bit sending CLS will clear all event standard event status register registers which in turn clears the status byte and bit 5 will clear Power on instrument 6 2 5 Status System Detail Status Register Sets TABLE 6 3 Register clear methods As shown in FIGURE 6 1 there are two register sets in the status system of the Model 350 Standard Event Status Register and Operation Event Register 6 2 5 1 Standard Event Status Register Set The Standard Event Status Register reports the following interface related instru ment events power on detected command syntax errors command execution errors query errors operation complete Any or all of these events may be reported in t
234. ned off during steady state con trol because it reacts too strongly to small disturbances The derivative setting D is related to the dominant time constant of the load similar to the I setting and is there fore set relative to I setting when used The Model 350 has a control setting that is not a normal part of a PID control loop Manual Output can be used for open loop control meaning feedback is ignored and the heater output stays at the user s manual setting This is a good way to put con stant heating power into a load when needed The Manual Output term can also be added to the PID output Some users prefer to set a power near that necessary to con trol ata setpoint and letthe closed loop make up the small difference Manual Output is set in percent of full scale current or power for a given heater range section 4 5 1 5 5 Manual Output should be set to 0 when not in use 2 13 4 ManualOutput 39 change in setpoint o p 3 pas o a E 7 LS actual temperature response P only too high time P only b P only too low c Pl d P I1 D e FIGURE 2 4 Examples of PID control Lake Shore www lakeshore com CRYOTRONICS 40 CHAPTER 2 Cooling System Design and Temperature Control 2 14 Manual Tuning 2 14 1 Setting Heater Range 2 14 2 Tuning Proportional Model 350 Temperature Controller There has been a lot written abouttuning closed loop control systems and specifically PID con
235. ng power supply used for Output 1 is turned completely off when Output 1 is off For best results use Output 2 for control and ensure Output 1 is off when controlling at very low temperatures If the Model 350 heater leads are too noisy and the above wiring techniques do not help Lake Shore offers the Model 3003 Heater Output Conditioner that may help section 17 Outputs 3 and 4 cannot power heaters directly when used in warm up control mode These unpowered outputs must be used to program an external power supply which in turn powers the heater This section describes choosing and installing an external supply Section 5 5 describes operation of warm up control mode 3 6 5 1 Choosing a Power Supply W Voltage Programmable the power supply must be voltage programmable so that Outputs 3 or 4 control output can control it Ideally the supply s programming input should have a range of O to 10 V that corresponds to O to 10 V range ofthe control output This guarantees that 0 to 100 of the control output scales to O to 100 power out ofthe supply Supplies with different programming input ranges can be used as described in section 3 6 5 4 Be aware that if the input voltage is not within the range of the power supply damage may result W DC Output Capable the power supply must be capable of continuous DC output Most commercial audio amplifiers are not suitable because they are AC coupled and cannot provide a DC output 3 6 5 Powering Out
236. not guarantee good electrical contact between the instrument and cabinet They should not be used for ground strapping unless paint is removed from under all screws Ensure that there is a 25 mm 1 in clearance on both sides of the instrument after rack mounting Description PN Qty Rack mount ear 107 440 2 Screw 6 32x3 8 PH FLHD MS SS 0 033 4 Rack mount handles 3 in black 107 433 2 Screw 8 32x3 8 PH FLHD MS SS 0 081 4 Remove and discard 4 screws from case replace with 4 screws from kit FIGURE 7 2 Model RM 1 rack mount kit 7 4 2 Option Card The Model 350 input option cards are field installable You will need a small Phillips Installation head screwdriver and the 5 64 in hex driver Follow this procedure to install an input option AWARN l NG To avoid potentially lethal shocks turn off controller and disconnect it from AC power before performing these procedures Lake Shore www lakeshore com CRYOTRONICS 162 CHAPTER 7 Options and Accessories 0 CAUTIO N The components on this board are electrostatic discharge sensitive ESDS devices Follow ESD procedures in section 8 11 to avoid inducing an electrostatic discharge ESD into the device 1 Turn Model 350 power switch Off Unplug power cord from wall outlet then instrument 2 Stand the unit on its face Use the hex driver to remove the 4 screws on both sides of the top cover Loosen the 2 rear bottom screws FIGURE 7 3 Remove Remove
237. nput parameter for each temperature zone This allows a different feedback sensor to be used for each temperature zone For exam ple a diode sensor can be used while cooling down from room temperature to 10 K at which point the Control Input could be switched to a Cernox sensor for tempera tures under 10 K To illustrate how the control parameters are updated in Zone mode consider the zone settings from the table below Starting from room temperature about 300 K and setting a setpoint of 2 K with Setpoint Ramping turned On the setpoint will begin ramping atthe current setpoint Ramp Rate then once the setpoint crosses 100 K the control parameters from Zone 8 will be used The setpoint ramp will then continue toward 2 K ata rate of 20 K min until crossing 50 K when the control parameters from Zone 7 are loaded This pattern will continue until the final setpoint value of 2 Kis reached or another setpoint is entered Note that Input B will be used in all zones greater than 10 K zones 4 to 8 and Input A will be used in all zones below 10 K zones 1 3 0 0 1 K Min Default 9 n a OK 50 20 0 0 0 Off 0 1 K Min Default 8 100 001 K 500 K 200 20 0 0 0 High 30 K Min Input B 7 50 001K 100K 185 25 0 0 0 Med 20 K Min Input B 6 25 001K 50K 150 30 0 0 0 Med 10 K Min Input B 5 15 001K 25K 100 30 0 0 0 Med 5 K Min Input B 4 10 001 K 15K 85 35 0 0 0 Med 2 K Min Input B 3 7 001K 10K 85 35 0 0 0 Med 0 9 K Min
238. nsor Second stage and Heater sample holder wiring not shown Drawing not to scale A for clarity Optical window if required FIGURE 2 3 Typical sensor installation in a mechanical refrigerator 2 10 7 Lead Soldering When you solder additional wire to short sensor leads be careful not to overheat the sensor Athermal anchor such as a metal wire clamp or alligator clip will anchorthe leads and protect the sensor Leads should be tinned before bonding to reduce the time that heat is applied to the sensor lead Clean the solder flux after soldering to prevent corrosion or outgassing in vacuum Model 350 Temperature Controller 2 10 8 Thermal Anchoring Leads 2 10 9 Thermal Radiation 2 10 10 Resistor Self Heating Versus Excitation 2 10 8 ThermalAnchoring Leads 33 Sensor leads can be a significant source of error if they are not properly anchored Heat will transfer down even small leads and alter the sensor reading The goal of thermal anchoring is to cool the leads to a temperature as close to the sensor as possi ble This can be accomplished by putting a significant length of lead wire in thermal contact with every cooled surface between room temperature and the sensor You can adhere lead wires to cold surfaces with varnish overa thin electrical insulator like cigarette paper They can also be wound onto a bobbin that is firmly attached to the cold surface Some sensor packages include a thermal anchor bobbin and wrapped lead wires to
239. nspect shipping containers for external damage before opening them Photograph any container that has significant damage before opening it Inspect all items for both visible and hidden damage that occurred during shipment If there is visible damage to the contents of the container contact the shipping company and Lake Shore immediately preferably within five days of receipt of goods for instruc tions on how to file a proper insurance claim Lake Shore products are insured against damage during shipment but a timely claim must be filed before Lake Shore will take further action Procedures vary slightly with shipping companies Keep all damaged shipping materials and contents until instructed to either return or discard them Open the shipping container and keep the container and shipping materials until all contents have been accounted for Check off each item on the packing list as it is unpacked Instruments themselves may be shipped as several parts The items included with the Model 350 are listed below Contact Lake Shore immediately if there is a shortage of parts or accessories Lake Shore is not responsible for any miss ing items if not notified within 60 days of shipment Ifthe instrument must be returned for recalibration replacement or repair a Return Authorization RMA number must be obtained from a factory representative before itis returned Refer to section 8 14 2 for the Lake Shore RMA procedure Items Included with Model 35
240. nt do not exclude restrict or modify the mandatory statutory rights applicable to the sale ofthe product to you CERTIFICATION Lake Shore certifies that this product has been inspected and tested in accordance with its published specifications and that this product met its published specifications atthe time of shipment The accu racy and calibration of this product at the time of shipment are trace able to the United States National Institute of Standards and Technology NIST formerly known as the National Bureau of Stan dards NBS FIRMWARE LIMITATIONS Lake Shore has worked to ensure that the Model 350 firmware is as free of errors as possible and that the results you obtain from the instrument are accurate and reliable However as with any com puter based software the possibility of errors exists In any important research as when using any laboratory equipment results should be carefully examined and rechecked before final con clusions are drawn Neither Lake Shore nor anyone else involved in the creation or production of this firmware can pay for loss of time inconvenience loss of use of the product or property damage caused by this product or its failure to work or any other incidental or conse quential damages Use of our product implies that you understand the Lake Shore license agreement and statement of limited warranty FIRMWARE LICENSE AGREEMENT The firmware in this instrument is protected by United States co
241. nterface Operation Model 350 Temperature Controller m Message Available MAV Bit 4 this bit is set when a message is available in the output buffer 6 2 6 2 Service Request Enable Register The Service Request Enable Register is programmed by the user and determines which summary bits of the Status Byte may set bit 6 RQS MSS to generate a Service Request Enable bits are logically ANDed with the corresponding summary bits FIGURE 6 4 Whenever a summary bit is set by an event register and its correspond ing enable bit is set by the user bit 6 will set to generate a service request The Service Request Enable command SRE programs the Service Request Enable Register and the query command SRE reads it From operation event register From standard event status register From operation event register DS s eee ao ms e s pe e 2 2 1 vecim ses Name ESL Status byte register STB RQS Generate service request reset by serial poll Read by STB EN ERENER us enable regster 28 64 32 26 8 4 2 1 name MSS FIGURE 6 4 Status byte register and service request enable register 6 2 6 3 Using Service Request SRQ and Serial Poll When a Status Byte summary bit or MAV bit is enabled by the Service Request Enable Register and goes from 0 to 1 bit 6 RQS MSS of the status byte will be set This will send a service request SRQ interrupt message to the bus controller The user
242. ntroller To set D first configure the front panel display to show the desired control loop infor mation then use the D key on the front panel A quick way to access the setting if the control loop information is not already being displayed is to press A B C or D on the front panel to temporarily display the control loop information while the new setting is entered Referto the section 4 3 for details on configuring the front panel display Menu Navigation D gt 0 to 200 Default 0 Interface Command PID 4 5 1 5 5 Manual Output Manual Output is a manual setting of the control output It can function in two differ ent ways depending on control mode In open loop control mode the Manual Output is the only output to the load You can directly set the control output from the front panel or overthe computer interface In closed loop control mode Manual Output is added directly to the output ofthe PID control equation In effect the control equa tion operates about the Manual Output setting The Manual Output setting is in percent offull scale Percent offull scale is defined as percent of full scale current or power on the selected heater range Refer to section 4 5 1 3 to set the Heater Out display Available full scale current and power are determined by the heater resistance Max Current setting and Heater Range Manual Output setting range is 0 to 100 with a resolution of 0 01 To set Manual Output first configure the
243. ntry is complete you must assign the new curve to an input The Model 350 does not automatically assign the new curve to any input Referto section 4 4 8 for details on assigning a curve to a sensor input Menu Navigation Curve Entry gt Edit Curve 21 59 Curve Points gt 1 200 Interface Command CRVPT 5 9 1 4 Thermocouple Curve Considerations The following are things to consider when generating thermocouple curves m You may enter temperature response curves for all types of thermocouples Enter curve data in mV K format with thermocouple voltage in millivolts and tempera ture in kelvin m The curve must be normalized to O mV at 273 15 K 0 C Thermocouple voltages in millivolts are positive when temperature is above 273 15 K and negative when temperature is below that point m Toconvertcurves published in Celsius to kelvin add 273 15 to the temperature in Celsius m Theinputvoltage ofthe Model 350 is limited to 50 mV so any part ofthe curve that extends beyond 50 mV is not usable by the instrument m A message of S OVER or S UNDER on the display indicates that the measured ther mocouple input is over or under the 50 mV range 5 9 2 View Curve 5 9 3 Erase Curve 5 9 4 Copy Curve 5 9 2 ViewCurve 99 The View Curve operation provides read only access to all standard and user curves To perform the View Curve operation follow this procedure 1 Press Curve Entry scroll to View Curve then press Enter
244. o 3 42 0 4 0 04 rd GR 50 100mK 2 317 71 858 6x107 t0000 sg t4 196rng 100nA 41 4 1 14 0 4 t4 00n 10 043trdg 0 2 411442 2 Q 0 07 rng 0 nA 12 i 0 5t t Jogo 100mK 21389 558 110 2x109 RS e 4 30 Q 0 1 rng 30nA 438 5 3 0 04 rdg 0 1 38 544 1 1 Temperature Control Catalog Appendix G Sensor Temperature Response Data Tables 2 Temperature Control Catalog Appendix E Temperature Measurement System 3 Tsp I2R R Typical Self Heating Error Excitation Current2 Sensor Resistance Thermal Resistance 4 Temperature Equivalent Noise Instrument Measurement Resolution Sensitivity 5 TABLE 1 3 Input Specifications 6 Temperature Equivalent Instrument Accuracy Instrument Gain Accuracy Instrument Offset Accuracy Sensitivity 7 Temperature Control Catalog Appendix D Sensor Calibration Accuracies 8 Total Uncertainty Instrument Accuracy Sensor Uncertainty Self Heating Error TABLE 2 1 Ultra low temperature considerations To determine the optimal excitation current consider that self heating can be cali brated out An estimate of the self heating can be attained either through analysis or by experimentation The sensor s calibration uncertainty remains constant at a par ticular temperature therefore as excitation currents are reduced the change in reading is due to self heating and instrument accuracy which is range dependent If t
245. o 45 control loops Display setup Press this key to configure the display 4 3 Max Min reset Press this key to reset the maximum and minimum readings for all inputs 4 4 13 Curve ene Press this key to view edit copy and erase temperature curves and to generate SoftCal Section 5 2 Front Panel Curve Entry 2 curves Operations Zone settings Press this key to enter user specified control parameters for up to ten temperature zones 5 3 Autotune Press this key to configure and execute the Autotune algorithm 5 2 Remote local Press this key to toggle the IEEE 488 Remote mode 4 6 3 1 Interface Press this key to configure the USB Ethernet and IEEE 488 interfaces AR ror USB 4 6 2 TONETNErNEN Ad for IEEE 488 Relays Press this key to configure the two rear panel relays 5 7 2 Alarm Press this key to configure the Alarm feature 5 7 1 A Press this key to navigate menus and to select parameters N A v Press this key to navigate menus and to select parameters N A Press this key to cancel a number entry or parameter selection You can also use this key to Escape exit menu navigate up one level in a setting menu which exits the menu if at the top level Press and N A hold for 3 s to reset instrument parameters to factory default values Enter Press this key to accept a number entry or a parameter selection You can also use it to navi N A gate deeper into a menu setting screen Press and hold for 3 s to lock or unlock the keypad 0 9
246. o build the integral contribution to the output Output I Pi e at Lake Shore www lakeshore com CRYOTRONICS 38 CHAPTER 2 Cooling System Design and Temperature Control 2 13 3 Derivative D 2 13 4 Manual Output Model 350 Temperature Controller By addingthe integral to proportional contributions the error that is necessary in a proportional only system can be eliminated When the error is at O controlling at the setpoint the output is held constant by the integral contribution The integral setting I is more predictable than the gain setting It is related to the dominant time con stant of the load As discussed in section 2 14 3 measuring this time constant allows a reasonable calculation ofthe integral setting In the Model 350 the integral term is not set in seconds like some other systems The integral setting can be derived by dividing 1000 by the integral seconds Icetting 1000 Iseconds The derivative term also called rate acts on the change in error with time to make its contribution to the output Output D pp By reacting to a fast changing error signal the derivative can work to boost the output when the setpoint changes quickly reducing the time it takes for temperature to reach the setpoint It can also see the error decreasing rapidly when the temperature nears the setpoint and reduce the output for less overshoot The derivative term can be useful in fast changing systems but it is often tur
247. o this it uses feedback from the control input sensorto calculate and actively adjustthe control output setting The Model 350 uses a control algo rithm called PID that refers to the three terms used to tune the control Refer to sec tion 4 4 10 for details on assigning a Control Input forthe closed loop feedback Refer to section 2 13 and section 2 14 for a detailed discussion of PID control and manual tuning In Closed Loop PID mode the controller will accept user entered Proportional Inte gral and Derivative parameters to provide 3 term PID control Manual output can be used during closed loop control to add to the calculated PID control output Menu Navigation Output Setup Output 1 2 3 or 4 0utput Mode Closed Loop PID 4 5 1 4 2 Zone Mode Optimal control parameter values are often different at different temperatures within a system Once control parameter values have been chosen for each tempera ture range or zone the instrument will update the control settings each time the setpoint crosses into a new zone Lake Shore www lakeshore com CRYOTRONICS 78 CHAPTER 4 Operation C CAUTION Model 350 Temperature Controller If desired the control parameters can be changed manually just like Closed Loop PID mode but they will be automatically updated once the setpoint crosses a zone boundary The control algorithm used for each zone is identical to that used in Closed Loop PID mode The Zone feature is useful
248. of a step change value in 45 readings or 4 5 s Model 350 Temperature Controller 4 4 9 Filter 73 The time constant time it takes to settle to within 36 8 ofthe step value after a step change fora given number of filter points can be derived using the following formula TC 2 0 1 In N N 1 where TC is one time constant and N is the number of filter points A reading is usually considered settled after six time constants TABLE 4 12 shows a sampling of filter settings and the resulting time constant settle time and equivalent noise bandwidth Filter points Ulmer Settle time Equivalent noise n 6 time constants bandwidth 1 4 TC 2 0 14s 0 95 1 733 Hz 4 0 355 21s 0 719 Hz 8 0 755 4 55 0 334 Hz 16 1 55s 9 35 0 161 Hz 32 3 15s 18 95 0 079 Hz 64 6 355 38 15 0 039 Hz TABLE 4 12 Filter settle time and bandwidth The filter window is a limit for restarting the filter If a single reading is different from the filter value by more than the limit the instrument will assume the change was intentional and restart the filter Filter window is set in percent of full scale range When the Model 3062 4 channel scanner option card is installed the time it takes to get a new reading is increased if more than one scanner channel is enabled ora channel is configured for a range that requires a reduced update rate This reduction in update rate modifies the time c
249. ofthe sensor being used For instance if a typical Cernox CX 1010 is used at 100 mK and 10 nA drive the instrument electronic accuracy would be 100 Q 0 04 21 389 Q or 108 6 Q This can then be converted to temperature by using the typical sensitivity at 100 mK 558 110 Q K 108 6 Q 558 110 Q K 0 2 mK The sensor calibration uncertainty is usually listed on the sensor s data sheet Forthe CX 1010 at 100 mK the uncertainty is 4 mK Contact Lake Shore for more informa tion concerning the uncertainties surrounding calibration drift and other sources of error that determine the uncertainties associated with the sensor The total measurement uncertainty is the sum of the self heating offset error instrument accuracy sensor calibration uncertainty For a typical CX 1010 sensor driven with 10 nA current at 100 mK the total uncertainty is 4 3 mK 0 2 mK 4mK 4 3 mK 0 2 mK 4 mK This total uncertainty can be calculated for other excitation currents and other sen sors which may result in different uncertainties Note that in this analysis these uncertainties are simply added together another common method of adding uncer tainties is to add the sum of squares method Either method of combining uncertain ties will illustrate the errors used to evaluate the various sensors and excitation currents Lake Shore www lakeshore com CRYOTRONICS 26 CHAPTER 2 Cooling System Design and Temperature Control Model 35
250. ollapsed m Hide Legend hides the legend in the chart to expand the data plot Help 3 m Getting Started launches a web page with basic chart recorder instructions m About provides information about the application including the software revi sion level 6 5 4 6 Information The information panel consists ofthe following two bits of information m Datapoint 4 the current datapoint number If logging data this also shows the total number of data points to be taken in the current data acquisition i e 522 of 1000 m Log File 5 the file path of the file that is currently being used to log data Lake Shore www lakeshore com CRYOTRONICS 136 CHAPTER 6 Computer Interface Operation 6 6 Command Summary Command name Form of the command input Syntax of user parameter input see key below Definition of first parameter Definition of second parameter This section provides a listing ofthe interface commands A summary of all the com mands is provided in TABLE 6 6 All the commands are detailed in section 6 6 1 and are presented in alphabetical order Brief description of command Input Curve Number Command INCRV input curve number gt term a nn input Specify input A D curve number Specify input curve 0 none 1 20 std curves 21 59 user curves FIGURE 6 12 Sample command format Query name Form ofthe query input Syntax of user parameter input see key below
251. on scanned input The maximum update rate for a scanned input is 10 rdg s distributed among the enabled channels Any channel configured as 100 KQ RTD with reversal on changes the update rate for the channel to 5 rdg s Automatically selects appropriate NTC RTD or PTC RTD range Room for 39 200 point CalCurves or user curves Improves accuracy of DT 470 diode to 0 25 K from 30 K to 375 K improves accuracy of platinum RTDs to 0 25 K from 70 K to 325 K stored as user curves Maximum and minimum Averages 2 to 64 input readings 10 Hz squarewave 1 6 4 Control There are 4 control outputs 1 6 4 1 Heater Outputs Outputs 1 and 2 1 6 4 Control Control type Update rate Tuning Control stability PID control settings Proportional gain Integral reset Derivative rate Manual output Zone control Setpoint ramping Closed loop digital PID with manual heater output or open loop 10 s Autotune one loop ata time PID PID zones Sensor dependent see Input Specifications table Oto 9999 with 0 1 setting resolution 1to 1000 1000 s with 0 1 setting resolution 1to 200 with 1 resolution Oto 100 with 0 01 setting resolution 10 temperature zones with P D manual heater out heater range control channel ramp rate 0 001 K min to 100 K min 25 O setting 50 0 setting Type Variable DC current source D Aresolution 16 bit Max power 75W 50W Max current 1 732A 1A Compliance voltage min
252. ondary DNS address actual hostname Assigned hostname actual domain Assigned domain mac addr Module MAC address This query returns the configured Ethernet parameters If the Ethernet interface is not configured then IP subnet mask gateway primary DNS and secondary DNS parameters will be 0 0 0 0 Operational Status Query OPST term bit weighting term nnn The integer returned represents the sum ofthe bit weighting ofthe operational sta tus bits Refer to section 6 2 5 2 fora list of operational status bits Lake Shore www lakeshore com CRYOTRONICS 152 OPSTE Input Format Remarks OPSTE Input Returned Format OPSTR Input Returned Format Remarks OUTMODE Input Format Example Remarks OUTMODE Input Format Returned Format Model 350 Temperature Controller CHAPTER 6 Computer Interface Operation Operational Status Enable Command OPSTE bit weighting term nnn Each bit has a bit weighting and represents the enable disable mask ofthe corre sponding operational status bit in the Operational Status Register This determines which status bits can set the corresponding summary bit in the Status Byte Register To enable a status bit send the command OPSTE with the sum ofthe bit weighting for each desired bit Refer to section 6 2 5 2 for a list of operational status bits Operational Status Enable Query OPSTE term bit weighting term nnn Referto section 6 2
253. onstant of the filter The time constant of the filter can be derived using the formula TC T In N N 1 where TC is one time constant T is the update rate of the channel in seconds per reading and N is the number of filter points Refer to section 4 4 7 2 for information on update rates of the Model 3062 TABLE 4 13 shows a sampling of enabled scanner channels with the number of filter points set to 8 and resulting time constant settle time and equivalent noise band width Scanner channels Time constant with 8 Settle time 6 time Equivalent noise TEL xe filter points constants bandwidth 3 4 TC 1 0 755 4 55 0 334 Hz 2 1 50s 9s 0 167 Hz 3 2 25s 13 55 0 111 Hz 4 3 00s 18 05 0 083 Hz 5 3 745 22 55 0 067 Hz TABLE 4 13 Example of a filter settle time and bandwidth fora Model 3062 4 channel scanner option card Menu Navigation Input Setup nput A B C or D Filter Off or On Input Setup nput A B C or D Filter Points gt 2 to 64 Input Setup ynput A B C or D Filter Window 196 to 10 Default Filter gt Off Filter Points gt 8 Filter Window 1096 Lake Shore www lakeshore com CRYOTRONICS 74 CHAPTER 4 Operation 4 4 10 Input Name 4 4 11 Temperature Limit 4 4 12 Preferred Units 4 4 13 Max Min 4 5 Output and Control Setup Model 350 Temperature Controller To increase usability and reduce confusion the Model 350
254. oom temperature Noise can be generated in lead cables when they are moved or vibrated This noise can be related to the triboelectric effect or changes in capacitance between conduc tors in the cable Cables carrying small signals should be fastened down without put ting strain on the connections This section explains warm up and temperature drift sensor installation and sensor self heating and thermal resistance When the Model 350 is first turned on it should be allowed to warm up for at least 30 mins before use to allow its internal temperature to stabilize Warm up is an exag gerated form of temperature drift because the temperature change inside the enclo sure is larger and faster than would be experienced in a laboratory setting Temperature drift change in reading with change in ambient temperature is small in the Model 350 and seldom a significant factor in absolute accuracy Measurement repeatability is often dominated by temperature drift and temperature change should be considered if the instrument is being installed in a rack If possible preci sion measurement instruments should not be placed in the same rack with large power supplies or other equipment that can change the rack temperature quickly Instrument racks should be well ventilated to prevent the buildup of heat Installation is an important part of measurements at cryogenic temperatures The measured sensor must be at the temperature of its surroundings for the m
255. or packages Less perma nent mountings require some pressure to hold the sensorto its mounting surface Pressure greatly improves the action of gasket material to increase thermal conduc tivity and reduce thermal gradients A spring clamp is recommended so that different rates of thermal expansion do not increase or decrease pressure with temperature change Lake Shore www lakeshore com CRYOTRONICS 32 CHAPTER 2 Cooling System Design and Temperature Control 2 10 6 Lead Wire Different types of sensors come with different types and lengths of electrical leads In general a significant length of lead wire must be added to the sensorfor properther mal anchoring and connecting to a bulk head connector at the vacuum boundary The lead wire must be a good electrical conductor but should not be a good thermal con ductor or heat will transfer down the leads and change the temperature reading of the sensor Small 30 AWG to 40 AWG wire made of an alloy like phosphor bronze is much better than copper wire Thin wire insulation is preferred and twisted wire should be used to reduce the effect of RF noise if it is present The wire used on the room temperature side of the vacuum boundary is not critical so copper cable is normally used t To room temperature Vacuum shroud Refrigerator first stage Vacuum space tie down Or Thermal anchor C bobbin Tyagenie tape Thermal anchor bobbin Cryogenic wire small diameter large AWG Se
256. or the National Physical Labo ratory in Great Britain These standards allow Lake Shore to calibrate sensors from 20 mK to above room temperature Calibrated sensors are more expensive than uncalibrated sensors of the same type because of the labor cryogen use and capitol equipment used in the process Precision calibration provides the most accurate temperature sensors available from Lake Shore Uncertainty from sensor calibration is almost always smaller than the error contributed by the Model 350 The Lake Shore Temperature Measurement and Control Catalog has complete accuracy specifications for calibrated sensors Calibrated sensors include the measured test data printed and plotted the coeffi cients of a Chebychev polynomial that have been fitted to the data and two tables of data points to be used as interpolation tables Both interpolation tables are opti mized to allow accurate temperature conversion The smaller table called a break point interpolation table is sized to fit into instruments like the Model 350 where it is called a temperature response curve Lake Shore www lakeshore com CRYOTRONICS 30 CHAPTER 2 Cooling System Design and Temperature Control 2 9 2 SoftCal 2 9 3 Sensors Using Standard Curves 2 9 4 Curve Handler 2 10 Sensor Installation Model 350 Temperature Controller It is important to look at instrument specifications before ordering calibrated sen sors A calibrated sensor is requir
257. or this zone 0 to 100 lt range gt Specifies the heater range for this zone Valid entries 0 Off 1 Low 2 Med 3 High lt input gt Specifies the sensor input to use for this zone O Default Use previously assigned sensor 1 Input A 2 Input B 3 Input C 4 Input D 5 Input D2 6 Input D3 7 Input D4 8 Input D5 for 3062 option lt rate gt Specifies the ramp rate for this zone 0 1 100 K min Configures the output zone parameters Refer to Paragraph 2 9 ZONE 1 1 25 0 10 20 0 0 2 2 10 term Output 1 zone 1 is valid to 25 0 K with P 10 20 D 0 a heater range of medium sensor input B anda ramp rate of 10 K min Output Zone Table Parameter Query ZONE lt output gt lt zone gt term n nn lt output gt Specifies which heater output to query 1 4 lt zone gt Specifies which zone in the table to query Valid entries 1 10 upper boundary gt lt P value l value gt lt D value gt lt mout value gt lt range gt lt input gt lt rate gt term nnnnn nnnnn nnannn nnnn nnnnn n n nnnn refer to command for description 7 1General 159 Chapter 7 Options and Accessories 7 1 General 7 2 Models 7 3 Accessories This chapter provides information on the models options and accessories available for the Model 350 temperature controller The list of Model 350 model numbers is provided as follows 350 Description of Models Standard temperature controller
258. ors safety should remain the highest priority and low imped ance from the instrument chassis to safety ground should always be maintained The power switch is part of the line input assembly on the rear panel of the Model 350 and turns line powerto the instrument on and off When the circle is depressed power is off When the line is depressed power is on This section details how to connect diode and resistive sensors to the Model 350 inputs Refer to section 4 4 to configure the inputs Refer to section 3 5 8 through sec tion 3 5 9 fora description of the optional capacitance input and thermocouple input The input connectors are 6 pin DIN 45322 sockets The sensor connector pins are defined in FIGURE 3 3 and TABLE 3 2 Four mating connectors 6 pin DIN plugs are included in the connector kit shipped with the instrument These are common con nectors so additional mating connectors can be purchased from local electronics suppliers They can also be ordered from Lake Shore as G 106 233 FIGURE 3 3 Sensor input connector Lake Shore www lakeshore com CRYOTRONICS 48 CHAPTER 3 Installation 3 5 2 Sensor Lead Cable 3 5 3 Grounding and Shielding Sensor Leads 3 5 4 Four Lead Sensor Measurement Model 350 Temperature Controller 1 l Current 2 V Voltage 3 None Shield 4 V Voltage 5 I Current 6 None Shield TABLE 3 2 Standard input connector details The sensor lead cable used outside the
259. owest PME Middle Highest Bipolar A 10V Outpt OV 10V Lowest Middle Highest Unipolar OV 5V Outpt 10V FIGURE 5 2 Unipolar and bipolar mode For example if Polarity is set to Bipolar then setting the Monitor Out 10 V parameter to O K and the Monitor Out 10 V parameter to 100 K will cause the analog output to correspond to the input temperature as shown in FIGURE 5 3 In this case if the actual reading was 50 K then the output would be at O V middle of the scale OK 50K 100 K Bipolar euy 10V OV 10V FIGURE 5 3 Analog output with polarity set to bipolar If we set the Polarity parameter to Unipolar the output would be as shown in FIGURE 5 4 In this case if the actual reading was 50 K the analog output would be 5 V middle of the scale OK 50K 100 K Unipolar E M OV 5V 10V FIGURE 5 4 Output with polarity parameter set to unipolar Menu Navigation Output Setup Output 3 or 4 Polarity Unipolar or Bipolar Output Setup Output 3 or 4 Monitor Out 10 V See note below Output Setup Output 3 or 4 Monitor Out O V See note below Output Setup Output 3 or 4 Monitor Out 10 V See note below Monitor Out 10 V 0 V and 10 V settings depend on the Monitor Units selected and are limited to the acceptable values of the selected units Default Polarity Unipolar Monitor Out 10 V0 0000 K Monitor Out 0 V0 0000 K Monitor Out
260. ox and click Finish 6 3 3 3 3 Manually install the driver Manually installing drivers differ between versions of Windows The following sections describe how to manually install the driver using Windows Vista and XP To install the driver you must be logged into a user account that has administrator privileges For Windows 7 and Vista 1 Connectthe USB cable from the Model 350 to the computer 2 Turn on the Model 350 3 Ifthe Found New Hardware wizard appears click Ask me again later 4 OpenDevice Manager Usethis procedure to open Device Manager a Clickthe Windows Start button and type Device Manager in the Start Search box b Clickonthe Device Manager link in the Search Results Under Programs dialog box c IfUserAccount Control is enabled click Continue on the User Account Control prompt eal Click View and ensure the Devices by Type check box is selected In the main window of Device Manager locate Other Devices in the list of device types In many instances this will be between Network adapters and Ports COM amp LPT If the Other Devices item is not already expanded click the icon Lake Shore Model 350 should appear indented underneath Other Devices If it is not displayed as Lake Shore Model 350 it might be displayed as USB Device If neither are displayed click Action and then Scan for hardware changes which may open the Found New Hardware wizard automatically Ifthe Found New Hardware wizard opens c
261. p external noise from entering the measurement A shield is most effective when it is near the measurement potential so the Model 350 offers a shield at measurement common The shield ofthe sensor cable should be connected to the shield pin of the input connector The shields should not be connected to earth ground on the instrument chassis One shield should be connected to the cryostat s ground as long as it is near earth ground Connecting at more than one point will cause a ground loop which adds noise to the measurement The shells ofthe input connectors are at the same potential as the shield pin on the Model 350 Older Lake Shore controllers are not configured this way All sensors including both two lead and four lead can be measured with a four lead technique The purpose of a four lead measurement is to eliminate the effect of lead resistance on the measurement If itis not taken out lead resistance is a direct error when measuring a sensor In a four lead measurement current leads and voltage leads are run separately up to the sensor With separate leads there is little current in the voltage leads so their resistance does not enter into the measurement Resistance in the current leads will not change the measurement as long asthe voltage compliance ofthe current source is not reached When two lead sensors are used in four lead measurements the short leads on the sensor have an insignificant resistance 3 5 5 Two Lead Sensor Measu
262. penEPXCe e Rx CUR E RODA 120 6 3 5 Message Flow Control sss ee 120 6 4 Ethernet Interface eei odo extre aee Ee ailes s pr pe pp eS 121 6 4 1 Ethernet Configuration ss sssscsrsrscririserrss irirna sa en 121 6 4 1 1 Network Address Parameters ssssssssssssssssssseeeee 121 6 4 1 2 Network Address Configuration Methods eeeeeee es 122 6 4 13 DNS Para METE S iiine estne pex ececenn N e Rae e ERRU pe 123 6 4 2 Viewing Ethernet Configuration ssssssssssss ee eee enee eee 125 64 24 LAN STATUS ss cccsecs error hte ERR RR OU RE D IER TET nance EN eee 125 6 4 2 2 MAC Address eie epe p E ISRAUARRG C EXTRDRE TET E RECO ET 126 6 4 2 3 Viewing Network Configuration Parameters and DNS Parameters i cese ede eX aco cives 126 6 4 3 TCP Socket Communication 6 cece cece eee 126 6 4 4 Embedded Web Interface 127 6 4 4 1 Connecting to the Web Interface 0 cece cece cece eens 127 6 4 4 2 Web Pages co cosseree eee HIR In BEREIT AR RH n ERR EN 127 6 5 UtIlICIBS derenan neen a weeds EA nadbentpt eeu rp Eom bos 129 6 5 1 Embedded Curve Handler 00 cece cece cece eee rererere 130 6 5 2 Ethernet Firmware Updater 131 6 5 3 Instrument Configuration Backup Utility ssssssssssssssssssss 132 6 5 4 Embedded Chart Recorder 133 6 5 4 1 Configuration Panel sssssssssssssssssssssssseeee eee 133 6 5 4 2 Starting Data Acquisition sssssssssssssssse 134 6 5 4 3 Chart Functiona
263. perature is in kelvin This query returns the temperature of the ceramic thermo couple block used in the room temperature compensation calculation Temperature Limit Command TLIMIT lt input gt lt limit gt term a nnnn lt input gt Specifies which input to configure A D D1 D5 for 3062 option lt limit gt The temperature limit in kelvin for which to shut down all control outputs when exceeded Atemperature limit of zero turns the temperature limit feature off for the given sensor input TLIMIT B 450 term if the temperature of the sensor on Input B exceeds 450 K all control outputs will be turned off Atemperature limit setting of O K turns the temperature limit feature off Temperature Limit Query TLIMIT lt input gt term a input Specifies which input to query A D D1 D5 for 3062 option lt limit gt term nnnn refer to command for description Control Tuning Status Query TUNEST term tuning status gt lt output gt lt error status gt lt stage status gt term n n n nn lt tuning status gt 0 no active tuning 1 active tuning lt output gt Heater output of the control loop being tuned if tuning 1 output 1 2 output 2 3 output 3 4 output 4 lt error status gt 0 no tuning error 1 tuning error stage status Specifies the current stage in the Autotune process If tuning error occurred stage status represents stage that failed If initial conditions are no
264. point value m Autotune PID sets values for P I and D parameters D is always set to 100 This mode is recommended when setpoint changes are frequent but temperature is allowed to stabilize between changes Stability at setpoint may be worse than Autotune PI in noisy systems Expect slightly less overshoot or undershoot than the other modes and control at the setpoint value When the Autotune process is initiated the P I D and Manual Output parameters are removed from the display and the Autotuning message appears in the lower right corner Below the Autotuning message the current status of the process is displayed The status message blinks to indicate thatthe algorithm is still processing If an error occurs the status message stops blinking and displays an error message containing the stage in which Autotune failed See TABLE 5 1 for a description ofthe Autotune stages reasons for failure and possible solutions When the process completes suc cessfully the previous P and D parameters are replaced by the newly acquired val ues To cancel the Autotune process press Autotune and choos Yes to the cancel Autotune prompt Lake Shore www lakeshore com CRYOTRONICS 86 CHAPTER 5 Advanced Operation Purpose for Stage Reason for Failure Possible Solution Curve not assigned to Input heater not Ensure curve is assigned to input heater is on and 0 Testing initial conditions Determine if Autotuning can be ini
265. program may then direct the bus controller to serial poll the instruments on the bus to identify which one requested service the one with bit 6 set in its status byte Serial polling will automatically clear RQS ofthe Status Byte Register This allows sub sequent serial polls to monitor bit 6 for an SRQ occurrence generated by other event types After a serial poll the same event or any event that uses the same Status Byte summary bit will not cause another SRQ unlessthe event register that caused the first SRQ has been cleared typically by a query ofthe event register The serial poll does not clear MSS The MSS bit stays set until all enabled Status Byte summary bits are cleared typically by a query ofthe associated event register section 6 2 6 4 The programming example in TABLE 6 4 initiates an SRQ when a command error is detected by the instrument 6 2 6 Status System Detail Status Byte Register and Service Request 115 Command or Operation Description ESR Read and clear the Standard Event Status Register ESE 32 Enable the Command Error CME bit in the Standard Event Status Register SRE 32 Enable the Event Summary Bit ESB to set the RQS ABC Send improper command to instrument to generate a command error Monitor bus Monitorthe bus until the Service Request interrupt SRQ is sent Initiate serial poll Serial poll the bus to determine which instrument sent the interrupt and clearthe RQS bit in the Status By
266. provided as the communication medium for the Ethernet interface of the Model 350 A TCP socket connection or simply socket con nection is a common connection protocol used by Ethernet devices The Transmis sion Control Protocol TCP is commonly used for creating a communication channel between one program on one computer and one program on another computer for example a web browser on a PC and a web server on the Internet In the case of the Model 350 the protocol is used to create a communication channel between one program on one computer and the command line interface of the Model 350 TCP uses error correction and collision avoidance schemes that make it a very reliable form of Ethernet communication but has drawbacks of having nondeterministic tim ing and can encounter relatively large delays depending on network conditions These delays can be on the order of seconds Sockets use port numbers to identify sending and receiving endpoints on network devices This allows for multiple sepa rate communication links to exist on each device The port number used for TCP socket connections on the Model 350 is 7777 A maximum of two simultaneous socket connections can be made to the Model 350 Any attempts to open a new socket while two socket connections are already open on a Model 350 will fail 6 4 4 Embedded Web Interface 6 4 4 Embedded Web Interface 127 The Model 350 provides a web interface via an embedded web server that runs on
267. provides a means of assigning a name to each ofthe four sensor inputs The designated input name is used on the front panel display whenever possible to indicate which sensor reading is being displayed It is also used in the output section ofthe custom display mode to denote which sensor input is associated with the displayed output to form a control loop Refer to section 4 2 3 for Alpha Numeric entry Menu Navigation Input Setup nput A B C or D Input Name 15 Character String Default Input A B C D Interface Command INNAME The Temperature Limit parameter provides a means of protecting your equipment from damage by shutting down all control outputs when the assigned temperature limit is exceeded on any sensor input The parameter is available for each of the four sensor inputs A temperature limit of O K default value turns this feature off Menu Navigation Input Setup nput A B C or D STemperature Limit OK to 2999K Default 0 0000 K Interface Command TLIMIT The Preferred Units parameter setting determines which units are used to display setpoint and max min parameters whenever these parameters are displayed in any display mode The sensor reading is also displayed in Preferred Units in all display modes except for the Custom display mode where each sensor location can be assigned specific display units Menu Navigation Input Setup nput A B C or D Preferred Units gt K C or Sensor The Max Min
268. put of the control loop being tuned The message blinks to indicate that the algorithm is still processing and displays the current stage of the process such as Stage 3 of 7 If the tuning process completes successfully then the message is removed and the new PID parameters are configured If the algorithm fails the mes sage stops blinking to indicate that it is no longer processing and a failure message appears to indicate which stage of the process failed There are situations where Autotune is not the answer The algorithm can be fooled when cooling systems are very fast very slow have a large thermal lag or have a non linear relationship between heater power and load temperature If a load can reach a new setpoint in under 10 sec with an appropriate I setting 500 the cooling system is too fast for Autotuning Systems with a very small thermal mass can be this fast Adding mass is a solution but is unappealing to users who need the speed for fast cycle times Manual tuning is not difficult on these systems because new settings can be tested very quickly Some systems are too slow for the Autotune algorithm Any system that takes more than 15 min to stabilize at a new setpoint is too slow with an appropriate I setting lt 5 Thermal lag can be improved by using the sensor and heater installation techniques discussed in section 2 10 to section 2 12 Lag times up to a few seconds should be expected much larger lags can be a problem Sy
269. puts 3 and 4 Using an External Power Supply 55 W Output Type most available voltage programmable power supplies are configured for voltage output This is different than Outputs 1 and 2 on the 350 which are configured for current output The differences between the two are not signifi cant when used in warm up mode W Output Voltage Lake Shore recommends supplies with a working output voltage between 10 V and 50 V Voltage higher than 50 V poses a shock hazard and should only be used if operator safety can be assured by the installer Voltage lower than 10 V becomes impractical because the current necessary provide any meaningful power is too high for most cryogenic wiring W Output Power there is no limit to the maximum power ofthe supply Typical warm up applications normally range between 25 W and 200 W 3 6 5 2 Power Supply Setup Follow all operation and safety instruction in the power supply manual during setup Considerthe following suggestions for protecting the power supply and heater load WI Short circuits are common in cryogenic lead wiring If the power supply does not specify that it is short circuit protected the power output should be wired with a fuse in series to prevent damage W Unipolar power supplies are designed to use a positive programming voltage and some can be damaged ifthe programming voltage is negative Be careful when wiring the system to maintain the correct polarity Also never set the control output of the
270. py right law and international treaty provisions To maintain the war ranty the code contained in the firmware must not be modified Any changes made to the code is at the user s risk Lake Shore will assume no responsibility for damage or errors incurred as result of any changes made to the firmware WinZip is a registered trademark of Nico Mak of Connecticut FIRMWARE LICENSE AGREEMENT continued Under the terms of this agreement you may only use the Model 350 firmware as physically installed in the instrument Archival copies are strictly forbidden You may not decompile disassemble or reverse engineer the firmware If you suspect there are problems with the firmware return the instrument to Lake Shore for repair under the terms of the Limited Warranty specified above Any unauthorized duplication or use of the Model 350 firmware in whole or in part in print orin any other storage and retrieval system is forbidden TRADEMARK ACKNOWLEDGMENT Many manufacturers and sellers claim designations used to distin guish their products as trademarks Where those designations appear in this manual and Lake Shore was aware of a trademark claim they appear with initial capital letters and the or symbol Alumel and Chromel are trademarks of Conceptech Inc Corporation CalCurve Cernox SoftCal Rox Curve Handler are trade marks of Lake Shore Cryotronics Inc Java is a registered trademark of Sun Microsystems
271. r excitation setting This keeps the power dissipated in the sensor ataminimum while still providing enough signal to provide accurate measurements In very low temperature applications it is recommended to turn autorange off and use a higher resistance range lower current to minimize the power dissipated in the sensor and therefore reduce self heating effects For example for a Cernox resistor that reads 10 kO at 150 mK the autorange algorithm would select the 10 kO range but manually selecting the 100 kO range provides 10 times less current and therefore 100 times less power into the sensor which may be required to significantly reduce the effects of self heating Current Reversal is also enabled by default in order to compensate for thermal EMF voltages Refer to section 4 4 4 for details on the Thermal EMF Compensation Current Reversal feature Refer to section 2 7 for details on self heating effects Menu Navigation Input Setup nput A B C or D Sensor Type NTC RTD Cernox Input Setup nput A B C or D Sensor Type NTC RTD Rox Interface Command INTYPE PTC resistor sensors include the platinum and rhodium iron sensors detailed in TABLE 4 7 More detailed specifications are provided in TABLE 1 2 The excitation cur rent for the PTC RTD sensor type can vary between 1 uA and 1 mA depending on resis tance range A resistance range selection is available in order to achieve better reading resolution When autoran
272. r with a valid temperature response curve Also determine an appropriate heater range as described in section 2 14 1 The system must be coarsely maintaining temperature within 5 K ofthe setpoint where new tuning parameters are desired in orderforthe Autotuning process to initiate Autotune works only with one control loop at a time and does not set the manual output or heater range For autotuning to work properly on a control loop with a scanner input assigned Model 3062 4 channel scanner option only that scanner input channel can be enabled all other scanner input channels must be disabled To initiate the Autotune process press Autotune then select an Autotune mode There are three Autotune modes available They result in slightly different system characteristics Autotune PI is recommended for most applications m Autotune P sets only the P parameter value and D are set to O no matter what the initial values are This mode is recommended for systems that have very long lag times or nonlinearity that prevents stable PI control Expect some overshoot orundershoot ofthe setpoint and stable temperature control below the setpoint value m Autotune PI sets values for both P and parameters D is set to 0 This mode is recommended for stable control at a constant temperature It may take slightly longerto stabilize after setpoint change than Auto PID Expect some overshoot or undershoot ofthe setpoint and stable temperature control at the set
273. ramp either up or down in temperature Always use the ramping feature to minimize temperature overshoot and undershoot When ramping is not used a setpoint change can cause the error used by the PID equation to become very large which causes the contribution of the control output equation to become largerthe longerthe error exists This will result in a large over shoot or undershoot once the setpoint temperature is reached since the I contribu tion will only decrease when the error polarity is reversed Use a ramp rate that keeps the control output from reaching the extremes of 100 or 0 while ramping for optimal results Lake Shore www lakeshore com CRYOTRONICS 82 CHAPTER 4 Operation Model 350 Temperature Controller The ramping feature is useful by itself but itis even more powerful when used with other features Setpoint ramps are often used with zone control mode As tempera ture is ramped through different temperature zones control parameters are auto matically selected for best control Ramps can be initiated and status read back using a computer interface During computer controlled experiments the instrument gen erates the setpoint ramp while the computer is busy taking necessary data When an incomplete ramp is shut off the setpoint will remain on the most current setting the reading will not jump to the end ofthe ramp If the input type or input curve is changed while a ramp is in progress both ramping and
274. re control is impossible ifthe Model 350 does not know which slope the sensor is on System overheating can result ifthe wrong coefficient is cho sen The user must select a temperature coefficient before control is switched to the capacitance input Menu Navigation Input Setup nput D Temp Coefficient Negative or Positive Interface Command INTYPE 4 4 6 3 Control Channel Changes The capacitance input continues control at a stable temperature established with another sensor Allow temperature to stabilize for one hour after large temperature changes to allow capacitance sensor recovery When the control channel is changed to the capacitance input the Model 350 auto matically changes the control setpoint to the present capacitance reading It is not necessary forthe userto write down the capacitance value and en ter a new setpoint Control parameters P and I may need to be changed for stable control When a Model 3062 4 Channel Scanner option is installed in the Model 350 4 addi tional channels D2 D3 D4 and D5 become available for use The channels are scanned with the Model 350 s Input D at a reduced update rate The scanner option channels can be configured for diode negative temperature coefficient resistor or positive temperature coefficient resistor sensors Specifications for the 4 channel scanner option are given in TABLE 4 9 Menu Navigation Input Setup nput D2 D3 D4 or D5 Sensor Type gt Disab
275. re web server on the Internet which is a DNS enabled network The web server hostname is www and it resides on the domain lakeshore com To connect to the web server from another device on the lakeshore com domain only the hostname www must be used To connect from any other domain on the Internet the entire fully qualified name consisting ofthe host name and the domain name www lakeshore com must be used Hostnames can only contain alpha numeric characters and hyphens but cannot begin or end with a hyphen A hostname can be assigned by a network administrator or ifthe Model 350 is con nected to a network with Dynamic DNS DDNS capability a DNS entry is automati cally created for it using the Preferred Hostname and Preferred Domain Name parameters and the assigned IP address Menu Navigation Interface Modify IP Config Preferred Hostname Valid Hostname String If DNS reverse lookup is enabled on the network DNS server and the DNS address parameters are correctly configured the Model 350 will perform a reverse lookup to determine if a hostname is assigned for the Model 350 s configured IP address This will occur regardless of whether the hostname was configured dynamically using DDNS or manually by the network administrator The returned hostname will appear in the Actual Hostname parameter in the View IP Config submenu ofthe Interface Setup menu Menu Navigation Read Only Interface View IP Config Actual Hos
276. recorder utility added Support for Model 350 added 21 Chart recorder and instrument configuration utilities updated to support Model 3062 scanner option card Ee Support for Model 224 increased TCP socket connections to 5 and added available TCP socket connections to Ethernet status page TABLE 8 9 Ethernet firmware updates 8 14 Technical Refer to the following sections when contacting Lake Shore for application assistance Inquiries or product service Questions regarding product applications price availability and shipments should be directed to sales Questions regarding instrument calibration or repair should be directed to instrument service Do not return a product to Lake Shore without a Return Material Authorization RMA number section 8 14 2 8 14 1 Contacting The Lake Shore Service Department is staffed Monday through Friday between the Lake Shore hours of 8 00 AM and 5 00 PM EST excluding holidays and company shut down days Contact Lake Shore Service through any of the means listed below However the most direct and efficient means of contacting is to complete the online service request form at http www lakeshore com Service Pages Request For Service aspx Provide a detailed description of the problem and the required contact information You will receive a response within 24 hours or the next business day in the event of weekends or holidays If you wish to contact Service or Sales by mail or telephone use the following
277. rement 3 5 6 Lowering Measurement Noise 3 5 5 Two Lead Sensor Measurement 49 Resistive sensor Diode option only Ve V A V l FIGURE 3 4 4 lead measurement There are times when crowding in a cryogenic system forces users to read sensorsina two lead configuration because there are not enough feedthroughs or room for lead wires If this is the case plus voltage to plus current and minus voltage to minus cur rent leads are attached at the back of the instrument or at the vacuum feedthrough The error in a resistive measurement is the resistance of the lead wire run with cur rent and voltage together If the leads contribute 2 Q or3Q toa 10 kQ reading the error can probably be tolerated Connectors are also a big source of error when making two lead measurements Con nector contact resistance is unpredictable and changes with time and temperature Minimize interconnections when making two lead measurements Refer to FIGURE 3 5 for an image of a two lead sensor measurement Lead resistance Sensor Lead j resistance FIGURE 3 5 2 lead sensor measurement Good instrument hardware setup technique is one ofthe least expensive ways to reduce measurement noise The suggestions fall into two categories 1 do not let noise from the outside enter into the measurement and 2 letthe instrument isolation and other hardware features work to their best advantage Here are some further suggestions Use four l
278. rface Command INTYPE Lake Shore www lakeshore com CRYOTRONICS 66 CHAPTER 4 Operation 4 4 1 Negative Temperature Coefficient NTC Resistor Sensor Input Setup 4 4 2 Positive Temperature Coefficient PTC Resistor Sensor Input Setup 4 4 3 Range Selection Model 350 Temperature Controller NTC resistor sensors include Cernox Rox Thermox and others detailed in TABLE 4 7 More detailed specifications are provided in TABLE 1 2 When configured for NTC RTD the Sensor Excitation setting becomes available in the Input Setup menu This setting allows a choice of 1 mV or 10 mV sensor excitation voltage This setting determines the sensor voltage atthe full scale of any given resistance range The 1 mV voltage level is designed to minimize self heating effects at the sensor when used at very low temperatures below approximately 300 mK The 1 mV voltage level however results in approximately 10 times more noise in the sensor reading than the corresponding resistance range at the 10 mV level reducing measurement resolution Therefore it is recommended that the 10 mV level be used for applications that do not require temperature measurement below about 300 mK The excitation current for the NTC RTD sensor type can vary between 10 nA and 1 mA depending on resistance range and sensor excitation level chosen When autoranging is enabled the range will be automatically selected so that the excitation voltage is at or below the senso
279. rface for the sensor and how the leads will be thermally anchored when choosing It can sometimes be confusing to choose the right sensor get it calibrated translate the calibration data into a temperature response curve that the Model 350 can understand and then load the curve into the instrument Lake Shore provides a vari ety of calibration services to fit different accuracy requirements and budgets Best Precision calibration All sensors can be calibrated over various temperature ranges Lake Shore has defined calibration ranges available for each sensortype Better SoftCal An abbreviated calibration 2 point 77 K and 305 K 3 point 4 2 K 77 K and 305 K or 3 point 77 K 305 K and 480 K which is avail able for 400 Series silicon diodes and platinum sensors Good Sensors using standard curves Silicon diodes follow standard curves Platinum resistors follow standard curves Ruthenium oxide Rox resistors follow standard curves Thermocouples follow standard curves GaAlAs diode carbon glass Cernox germanium and rhodium iron sensors can be purchased uncalibrated but must be calibrated to accurately read in temperature units TABLE 2 2 Sensor diode sensor calibrations To calibrate Lake Shore compares a sensor with an unknown temperature response to an accepted standard Lake Shore temperature standards are traceable to the U S National Institute of Standards and Testing NIST
280. rogramming input ofthe power supply has a range of less than OV to 10 V to ensure full output resolution and protection against overloading the external supply pro gramming inputs The output voltage is proportional to the ratio of resistors R1to R2 Vout 10V x R1 R1 R2 It is also important to keep the sum of R1 R2 1000 Q or the Model 350 output may not reach the output voltage setting due to internal overload protection For a programming input range of O V to 5 V recom mended values are R1 R2 2000 Q Fora programming input range of OV to 1 V recommended values are R1 500 Q R2 4500 Exact resistor value type and tol erance are generally not important for this application Model 350 Power supply Output 3 R2 Program input R1 Output 3 Program input FIGURE 3 11 Voltage divider circuit for Output 3 Chapter 4 Operation 4 1 General This chapter provides instructions for the general operating features of the Model 350 temperature controller Advanced operation is in Chapter 5 Computer interface instructions are in Chapter 6 Direct Menu LED operation number pad annunciators InputSetup CurveEntry Remote Local Exit Menu ooo ise 1 Ethernet OutputSetup ZoneSettings interface e G Um oooO Max Min Reset Alarm Coe amp LED annunciators FIGURE 4 1 Model 350 front panel 4 1 1 Understanding Each feature that is discussed in this chapter will
281. room temperature thermometer near the terminal block 3 Allow the instrument to warm up for at least 1 2 hr without moving or handling the sensor 4 Ifcalibrating with a short skip to step 6 otherwise insert the thermocouple into the ice bath liquid nitrogen helium Dewar or other known fixed temperature 5 Readthe displayed temperature If the temperature display is not as expected check to be sure that the thermocouple is making good thermal contact If possi ble add a thermal mass to the end ofthe thermocouple 6 PressInput Setupand select the corresponding sensor input Scroll down to the Room Calibration parameter and press Enter 7 Thecurrenttemperature reading is displayed in kelvin Press Enter to enter Num ber Entry mode Enterthe true temperature that the thermocouple should read If input is shorted then enter the actual room temperature measured by the thermometer Press Enter to save the value 8 To verify calibration check that the temperature reading for the calibrated input matches the room temperature calibration setting value Any previous calibration can be cleared using the Clear Calibration submenu Menu Navigation Input Setup Room Calibration Clear Calibration Default Room calibration cleared When a Model 3061 capacitance option is installed in the Model 350 a setting of Capacitance becomes available under the Sensor Type parameter in the Input Setup menu The standard sensor inputs can still
282. ropyl alcohol rinse HTR 25 25 Q Cartridge Heater The heater features precision wound nickel chromium resistance wire magnesium oxide insulation 2 solid pins non magnetic package and has UL and CSA compo nent recognition The heater is 25 O 6 35 mm 0 25 in diameter by 25 4 mm 1 in long The 25 Q rating is in dead air With proper heat sinking the cartridge heater can handle many times this dead air power rating HTR 50 50 O Cartridge Heater The heater features precision wound nickel chromium resistance wire magnesium oxide insulation 2 solid pins non magnetic package and has UL and CSA compo nent recognition The heater is 50 Q 6 35 mm 0 25 in diameter by 25 4 mm 1in long The 50 Q rating is in dead air With proper heat sinking the cartridge heater can handle many times this dead air power rating RM 1 Rack Mounting Kit Mounting brackets ears and handles to attach 1 Model 350 to a 482 6 mm 19 in rack mount cabinet See FIGURE 7 2 VGE 7031 IMI 7031 Varnish formerly GE 7031 Varnish 1 pint can IMI 7031 Insulating Varnish and Adhesive possesses electrical and bonding properties which when combined with its chemical resistance and good saturating properties make it an excellent material for cryogenic tem peratures As an adhesive IMI 7031 bonds a variety of materials has fast tack time and may be air dried or baked It is also an electrically insulating adhesive at cryogenic temperatures an
283. rpreted as infinite and will therefore respond as if setpoint ramping were off RAMP 1 1 10 5 term when Output 1 setpoint is changed ramp the current set point to the target setpoint at 10 5 K minute Control loop settings are assigned to outputs which results in the settings being applied to the control loop formed by the output and its control input Control Setpoint Ramp Parameter Query RAMP lt output gt term n lt output gt Specifies which output s control loop to query 1 4 lt off on gt lt rate value gt term n nnnn refer to command for description Control Setpoint Ramp Status Query RAMPST lt output gt term n lt output gt Specifies which output s control loop to query 1 4 lt ramp status gt term n lt ramp status gt 0 Not ramping 1 Setpoint is ramping Lake Shore www lakeshore com CRYOTRONICS 154 CHAPTER 6 Computer Interface Operation RANGE Input Format Remarks RANGE Input Format Returned Format RDGST Input Format Returned Format Remarks RELAY Input Format Example RELAY Input Format Returned Format Model 350 Temperature Controller Heater Range Command RANGE lt output gt lt range gt term n n lt output gt Specifies which output to configure 1 4 lt range gt For outputs 1 and 2 0 Off 1 Range 1 2 Range 2 3 Range 3 4 Range 4 5 Range 5 For outputs 3 and 4 0 Off 1 On The range setting has no effect
284. s and intermittent lockups 8 2 1 New Installation 1 Checkthatthe instruments interface is set to USB 2 Check that the USB driver is installed properly and that the device is functioning In Microsoft Windows the device status can be checked using Device Manager by right clicking Lake Shore Model 350 Temperature Controller under Ports COM amp LPT or Other Devices and then clicking Properties Refer to section 6 3 3 for details on installing the USB driver 3 Check that the correct com port is being used In Microsoft Windows the com port number can be checked using Device Manager under Ports COM amp LPT 4 Check that the correct settings are being used for communication Refer to section 6 3 3 for details on installing the USB driver 5 Check cable connections and length Send the message terminator 7 Send the entire message string at one time including the terminator Many ter minal emulation programs do not D 8 Send only one simple command ata time until communication is established 9 Be sure to spell commands correctly and use proper syntax 8 2 2 Existing 1 Powerthe instrument off then on again to see if itis a soft failure Installation No Longer 2 Powerthe computer off then on again to see if communication port is locked up ki 3 Checkall cable connections Working 4 Checkthatthe com port assignment has not been changed In Microsoft Windows the com port numbercan be checked using Device Manager under
285. s locked A three digit keypad lock code locks and unlocks the keypad The factory default code is 123 The code can be changed only through the computer interface If instrument parameters are reset to default values the lock code resets also The instrument can not reset from the front panel with the keypad locked To lock the keypad press and hold Enter for 5 s Use the numeric keypad to enter the three digit lock code If the lock code is accepted Keypad Locked will be dis played for 3 s and the display will return to normal Changes attempted to any parameters result in a brief display ofthe Keypad Locked message To unlock the keypad press and hold Enter for 5 s Use the numeric keypad to enter the three digit lock code If the lock code is accepted Keypad Unlocked will be displayed for 3 s and the display will return to normal All Model 350 parameters are now accessible 5 1 General 85 Chapter 5 Advanced Operation 5 1 General 5 2 Autotune This chapter provides information on the advanced operation ofthe Model 350 tem perature controller The Model 350 can automate the tuning process of typical cryogenic systems with the Autotune feature For additional information aboutthe algorithm refer to section 2 15 Before initiating the Autotune process properly configure the cooling system with control input sensor and heater output to make it capable of closed loop control Assign the control senso
286. section 4 4 11 for temperature limits Menu Navigation Output Setup Output 1 2 3 or 4 Output Mode Open Loop 4 5 1 5 Control Parameters Once the output mode is chosen the control parameters can be used to begin con trolling temperature Control Input is used to create a control loop The P I and D parameters provide fine tuning ofthe control algorithm Manual Output provides a baseline output power about which to control Setpoint is used to set the desired tar get temperature and Heater Range is used to turn on the control output as well as to setthe power range ofthe output These parameters are described in detail in section 4 5 1 5 1 to section 4 5 1 5 8 4 5 1 5 1 Control Input For closed loop control Closed Loop PID Zone Warm Up Supply a control loop must be created A control loop consists of a control output for controlling the temperature and an input for feedback into the control algorithm Use the Control Input parame terto assign the control input sensorto the desired output Inthe Monitor Out mode the Control Input parameter is used to determine the source ofthe output voltage In the Open Loop mode the Control Input parameter can be set simply for convenience in order to easily access the associated output s Manual Out put and Heater Range parameters using the Direct Operation keys Refer to section 4 2 1 1 for details on Direct Operation keys 4 5 1 HeaterOutputs 79 Menu Navigation Output Setup
287. sed In the On mode the relay is ener gized so the NO contacts will be closed and the NC contacts will be open In the Alarm mode the relay will activate based on the state of the configured Alarm Input sensor When the Alarm to Follow parameter is set to Low the relay will energize if the con figured Alarm Input sensor goes into a low alarm state If it is set to High the relay will energize ifthe configured Alarm Input sensor goes into a high alarm state If the Alarm to Follow parameter is set to Both the relay will energize if the configured Alarm Input sensor goes into either a low alarm or a high alarm state Menu Navigation Relays Relay 1 Relay 2 Mode Off On Alarm Relays Relay 1 Relay 2 Alarm Input Input A B C D Relays Relay 1 Relay 2 4Alarm to Follow Low High Both Default Mode Off Alarm Input Input A Alarm to Follow Both Interface Command RELAY The Model 350 has 20 standard curve locations numbered 1 through 20 At present not all locations are occupied by curves the others are reserved for future updates If a standard curve location is in use the curve can be viewed using the view operation Standard curves cannot be changed by the user and reserved locations are not avail able for user curves 5 8 1 Curve Header Parameters 5 8 2 Curve Breakpoints 5 8 1 CurveHeaderParameters 95 The Model 350 has 39 user curve locations numbered 21 through 59 Each location can hold
288. sed to create solder bumps for microelectronic chip attachments and also as gaskets for pressure and vacuum sealing purposes ID 10 31 Indium Disks are 7 92 mm diameter x 0 13 mm 0 312 in diameter x 0 005 in ID 10 56 Indium Disks are 14 27 mm diameter x 0 127 mm 0 562 diameter x 0 005 in IF 5 Indium Foil Sheets Quantity 5 When used as a washer between DT 470 CU silicon diode or other temperature sensors and refrigerator cold stages indium foil increases the thermal con tact area and prevents the sensor from detaching due to vibration It also may be used as a sealing gasket for covers flanges and windows in cryogenic applications Each sheet is 0 13 mm x 50 8 mm x 50 8 mm 0 005 in x 2 in x 2 in GAH 25 Apiezon H Grease 25 g Tube It is designed for general purposes where operating tempera tures necessitate the use of a relatively high melting point grease Melting point is 523 K 250 C Can be removed using Xylene with an isopropyl alcohol rinse GAN 25 Apiezon N Grease 25 g Tube General purpose grease well suited for cryogenic use because of its low viscosity It is often used as a means of thermally anchoring cryogenic sensors as well as lubricating joints and o rings Contains high molecular weight polymeric hydrocarbon additive that gives it a tenacious rubbery consistency allowing the grease to form a cushion between mating surfaces Melting pointis 316 K 43 C Can be removed using Xylene with an isop
289. sed to heat sink mea surement leads Mixing chamber chamber where cooling action takes place Holds both 3He rich liquid and dilute 3He separated by a phase boundary When 3He is depleted from the mix by the still more crosses the phase boundary to maintain equilibrium In doing so itis expanded into diluted by the He creating cooling of the chamber Best location for temperature control sensor and resistive heater The heater output can control tem perature by driving the heater under closed loop PID control or open loop control Load sample holder end of the mixing chamber where experiments can take place May either be part of or attached to the mixing chamber and it is often designed for a unique purpose Requires a separate temperature sensor if its temperature is differ ent from the mixing chamber 3He cryostats are the least complex systems capable of reaching temperatures down to 300 mK Even atsuch relatively warm temperatures the benefits of a well designed resistance bridge must be considered when selecting instrumentation FIGURE 2 2 illustrates the basic features Helium Dewar Vacuum insulation 4 He reservoir Vacuum space 1K pot Radiation shield Heat exchangers 35e evaporator Sample holder Vacuum chamber FIGURE 2 2 3He cryostat Helium Dewar vacuum insulated Dewar large enough to contain the following compo nents Sometimes includes a nitrogen outer jacket to improve efficiency Lake Shor
290. selected output is configured as a control loop output then all associated control loop parameters will be displayed When viewing the Custom Display screen the configured Displayed Output is signified by L1 L2 L3 or L4 followed by the control loop input if applicable The L character stands for Loop but will be displayed even for outputs that are not con figured as control loop outputs Menu Navigation Display Setup Displayed Output Output 1 2 3 4 m Default Output 1 Interface Command DISPLAY 4 3 2 Display Contrast 4 4 Input Setup Display ELEME NEAN 4 3 2 DisplayContrast 65 The front panel LCD display contrast can be adjusted for optimal viewing The default value should work well in most standard room temperature environments but devia tions from room temperature and extreme viewing angles can cause the display con trast to require adjustment for optimal viewing Menu Navigation Display Setup Display Contrast 1 to 32 Default 28 Interface Command BRIGT The Model 350 supports a variety of temperature sensors manufactured by Lake Shore and other manufacturers An appropriate sensor type must be selected for each input If the exact sensor model is not shown use the sensor input performance chart in TABLE 4 7 to choose an input type with similar range and excitation For additional details on sensors refer to the Lake Shore Temperature Measurement and Control Catalog or visit our website at www lake
291. sensors span ning to 420 K The instrument automatically selects the optimal current and gain lev els for you once the sensor type is selected and automatically scales current to minimize self heating effects at low temperatures The patented input circuitry elim inates any errors associated with grounding inconsistencies making it easier to achieve reliable measurements at ultra low temperatures With the ability to label each sensor input channel with a customized name it s also easy to identify the mea sured values being displayed Field installable input option cards can expand your sensor selection to include sili con diodes like DT 670 capacitance sensors or thermocouples Once installed the option input can be selected and named from the front panel like any other input type These option cards further expand the application versatility ofthe Model 350 temperature controller by allowing specialized sensors to be switched in and out to achieve specific measurement objectives For example addition of the thermocouple input option enables continuous measurement to 1000 K and above Alternatively the capacitance sensor option card enables a magnetics impervious capacitance temperature sensor to be temporarily switched in for elimination of magneto resis tive effects while taking low temperature sample measurements under high or changing fields Diode sensor support is provided by the 4 channel scanner option card which also enables use
292. set a Ser vice Request Enable Register bit and the corresponding summary bit is set in the Sta tus Byte the RQS MSS bit of the Status Byte will be set which in turn sets the Service Request hardware line on the bus 6 2 4 6 Reading Registers You can read any register in the status system using the appropriate query command Some registers clear when read others do not section 6 2 4 8 The response to a query will be a decimal value that corresponds to the binary weighted sum of all bits in the register TABLE 6 2 The actual query commands are described later through out section 6 2 4 Position B7 B6 B5 B4 B3 B2 B1 BO Decimal 128 64 32 16 8 4 2 1 Weighting 27 26 25 24 23 22 21 20 Example If bits 0 2 and 4 are set a query of the register will return a decimal value of 21 1 4 16 TABLE 6 2 Binary weighting ofan 8 bit register 6 2 4 7 Programming Registers The only registers that may be programmed by the user are the enable registers All other registers in the status system are read only registers To program an enable register send a decimal value that corresponds to the desired binary weighted sum of all bits in the register TABLE 6 2 The actual commands are described throughout section 6 2 4 6 2 5 Status System Detail Status Register Sets 111 6 2 4 8 Clearing Registers The methods to clear each register are detailed in TABLE 6 3 A S NN ERE NR Condition registers No
293. shore com Any unused input should be set to disabled Format 10nA to 1 mA decade steps in TM Negative Temperature NTCRTD OQ to300kO power autorange log FERES Carbon Glass Coefficient NTC RTD Cernox 10 Ranges maintains lt 10 mV Negative oK Germanium Rox or lt 1mV depending and Thermox on sensor exci tation setting 100 nA to 1 mA i Platinum RTD PT 100 Series Platinum Rhodium Iron RTD uen y E VAR ERA ed Positive Q K RF 800 Rhodium lron Option 3062 only 8 diu 8 RF 100 Rhodium Iron maintains 10 mV Chromel AuFe 0 07 Thermocouple m Type E Chromel Constantan t Option 3060 only Thermocouple 50 mV NA Positive mv K Type K Chromel Alumel Type T Copper Constantan Capacitance z O nF to 150 nF 2 3 496 kHz Positive or N A Option 3061 only Capacitance ranges 1 mA 10 mA square negative ia Silicon Diode DT 400 Series DT 500 Series Option 3062 only Diode 0V 2 5V 10 pA 1 mA Negative V K DT 600 Series Gallium Aluminum Arsenide Diode Option Diode 0V 10V 10 pA 1 mA Negative WK TG 120 Series 3062 only Refer to the Lake Shore Temperature Measurement and Control Catalog for details on Lake Shore temperature sensors This option will be available soon TABLE 4 7 Sensor input types Menu Navigation Input Setup nput A B C or D Sensor Type Disabled PTC RTD Platinum NTC RTD Cernox Thermocouple Capacitance Default NTC RTD Inte
294. sistance The thermal noise ofa sensor drops as the temperature is reduced and at low temperatures the sensor ther mal noise becomes negligible so high resistance sensors at low temperatures are not impacted by the sensor thermal noise The instrument noise measurement resolu tion listed in TABLE 1 3 was verified with a sensor cooled to 4 2 K so that the result ing instrument noise best fits what will be seen in an actual measurement Noise measurements of high value resistances at room temperature will be significantly higherthan the noise measured at low temperatures All digitally controlled instruments emit some high frequency noise both through the air and on their leads Emission from a Model 350 is very low and will not affect sen sor measurements ifthe instrument is installed properly The high frequency noise can interfere with very sensitive measurements being made in the same Dewar Inter ference can be minimized by separating the instruments and their leads outside the Dewar and placing ferrite beads on the Model 350 measurement leads nearthe Dewar to stop the noise from getting inside Wrapping leads through the large beads more than one time improves their attenuation of unwanted signals Lake Shore sells a clamp on ferrite bead as part number 2071 Amore common source of digital noise than the instrument itself is digital computers used for data acquisition Computers with their high clock speeds generate a wide spectrum of no
295. sssssssssssseee eee 19 2 4 3 Resistance Ranges cte enruspesse piace ue RE E E US ERR E RETE 19 2 4 4 Measurement Circuit 0 t e een 19 2 4 4 1 Shielding and Grounding Theory ssssssssseeeee 20 2 4 25 2 Shields ciis tette rt Een e teer b RA br XE RES 20 2 4 4 3 Electrical Isolation sssssssssssssssssss cece e eee e eee e ees 20 2 4 4 4 Active Common Mode Reduction cece cece eee eee e eens 21 2 4 4 5 Matched Impedance Current Source cece es 21 2 4 5 Measurement Speed and Filtering sss 21 NOISE SOULCES aeie nnen be RUE TUR RAAMEAT RR ATCREUEARUPUASE E d AUT Sus 21 2 5 1 Induced Electrical Noise sisse eh 21 2 5 2 Ground Loop NOISE escises esu ee eR EROR REI e aH E XD URROSEEREIE YE 22 2 5 3 Analog Circuit NOIS cece cence eee e eme 22 2 5 4 Digital Circuit NOISC cece cece cence ee 22 Lake Shore www lakeshore com CRYOTRONICS Model 350 Temperature Controller 25 5 Resistor Thermal NOE ioci r i p ER DPPrvER RR Rd ER AN YE Ir 3 AE 23 25 6 Vibration NOISE poe ere e tes sh ckdnersiawungarenthsagadc is 23 2 6 Measurerriemt EFTOF sisse aaO S EY Rd TY EPAVELE KE I pEERC EVER ERE EAS 23 2 6 1 Warm Up and Temperature Drift 23 2 6 2 Sensor Installations screen Ga E RR ET RR EU Peed RRS 23 2 6 3 Sensor Self Heating and Thermal Resistance 0 c cece ee ee ee eens 23 2 6 4 Lead ResistdliCe cioe e ERR TU ETIANI UP Te ga dum eed 24
296. stant if correct for the system being controlled would result in a system that stabilizes at a new setpoint in between 5 min and 10 min To set I first configure the front panel display to show the desired control loop infor mation then use the I key on the front panel A quick way to access the setting if the control loop information is not already being displayed is to press A B C or D on the front panel to temporarily display the control loop information while the new setting is entered Refer to section 4 3 for details on configuring the front panel display Menu Navigation I 0 to 1000 Default 20 Interface Command PID 4 5 1 5 4 Derivative D The derivative parameter sometimes called rate is the D part ofthe PID control equation The derivative time constant should normally be somewhere between 1 4 and Vsthe integral time in seconds if used at all As a convenience to the operator the Model 350 derivative time constant is expressed in percent of 1 4 the integral time The range is between 0 and 200 Start with settings of 0 50 or 100 and determine which setting gives you the type of control you desire Do not be sur prised if the setting you prefer is 0 Note that by using a percent of integral time derivative scales automatically with changes in the integral value and does not have to be revisited frequently Lake Shore www lakeshore com CRYOTRONICS 80 CHAPTER 4 Operation Model 350 Temperature Co
297. stant N A 3 496 kHz square current reversal current wave 100 Q Platinum option 1000 Supported Q Platinum option Germa Silicon Most thermocouple CS 501GR sensors nium Carbon Glass Cernox GaAlAs types and Rox DT 470 DT 670 DT 500 D DT 470 Type E Type K Type T Standard DT 500 E1 DT 670 ds dido ou AuFe 0 07 vs Cr N A curves PT 100 DT 500 D AuFe 0 0336 vs CR PT 1000 DT 500 E1 eee RX 102A RX 202A Screw terminals in a Input A 6 pin DIN 6 pin DIN ceramic 6 pin DIN connector isothermal block Number of inputs Input configuration Supported option cards Option slots Isolation A D resolution Input accuracy Measurement resolution Maximum update rate Maximum update rate scanner Autorange User curves SoftCal Math Filter Excitation frequency TABLE 1 4 Sensor input configuration 4 8 with the Model 3062 Inputs can be configured from the front panel to accept any ofthe supported input types Thermocouple capacitance and diode inputs require an optional input card that can be installed in the field Once installed the additional inputs can be selected from the front panel like any other input type Thermocouple 3060 capacitance 3061 or scanner 3062 1 Sensor inputs optically isolated from other circuits but not each other 24 bit Sensor dependent refer to Input Specifications table Sensor dependent refer to Input Specifications table 10 rdg s on each n
298. stem nonlinearity is a problem for both autotune and manual tuning It is most commonly noticed when controlling nearthe maximum or minimum temperature of a temperature control system It is not uncommon however for a user to buy a cryogenic cooling system specifically to operate near its minimum temperature Ifthis is the case try to tune the system at 5 degrees above the minimum temperature and gradually reduce the setpoint manu ally adjusting the control settings with each step Any time the mechanical cooling action of a cryogenic refrigerator can be seen as periodic temperature fluctuations the mass is too small or temperature too low to autotune 2 16 Zone Tuning 2 17 Thermoelectric Devices 2 14 4 TuningDerivative 43 Once the PID tuning parameters have been chosen for a given setpoint the whole process may have to be done again for other setpoints significantly far away that have different tuning needs Trying to remember when to use which set of tuning parameters can be difficult The Model 350 has a Zone feature as one of its tuning modes that can help To usethe Zone feature you must determine the besttuning parameters for each part ofthe temperature range of interest Then enterthe parameters into the Model 350 where up to 10 zones can be defined with different P D heater range manual out put ramp rate and control input settings An upper boundary setting is assigned as the maximum temperature forthat zone The min
299. summary bit forthe register set in the Status Byte You may write to or read from an enable reg ister Each event register bitis logically ANDed to the corresponding enable bit ofthe enable register When you set an enable register bit and the corresponding bit is set in the event register the output summary ofthe register will be set which in turn sets the summary bit ofthe Status Byte register 6 2 4 StatusSystemOverview 109 Er aa tatus register TENE PU Dmm p butter Ss a a my P Bp standardevent 7 6 5 4 T3 2 3 0 95 Status enable register Noe NE m FESE Est PON wea me ex is ove onc Name PON Power on CME Command error EXE Execution error YE Query error Bi Hag ee i complete Status byte register iz s 4 83 2 21 oe Bit TUM ia Name RQS Generate service request reset by serial poll MSS Read by STB P Service request 7 I IP 7 Bit enable register Nac T Noti nee Not SRE SRE ssa Name OSB Operation summary bit Operation z e s 3 2 2 9 9 mos seveeremest gt condition register cow cat arune Roc rama aea ovo aru Name MSS Master summary status bit OPST ESB Event status summary bit Eo v Y d MAV Message available summary bit UE ERIRESENESERESEEM event register Opeth cow cat arune NRDG RAM mea vez OVLD A 4RM Name Doerr operationevent 7 T6 s afs 2 4 9 5 enable no Ei OPSTE OPSTE ATUNE
300. t Vacuum chamber Still Heat exchangers Mixing chamber Sample holder FIGURE 2 1 Dilution refrigerator Helium Dewar vacuum insulated Dewar large enough to contain the following compo nents Sometimes includes a nitrogen outer jacket to improve efficiency or supercon ducting magnet coil when needed 4He reservoir reservoir of liquid He at atmospheric pressure that provides bulk cooling down to 4 2 K Pre cools gas entering the vacuum space and acts as a radiation shield for refrigeration components Vacuum space insulates refrigeration components and provides a clear workspace 1K pot 4He evaporator pumped reservoir of 4He maintained at 1 K Used in the process of condensing 3He rich gas returning from pumping system Also used as a heat sink for measurement leads Good location for a temperature sensor for cool down moni toring and troubleshooting Still heat exchanger chamber used to evaporate 3He out of a dilute 3He mix liquid He containing some 3He sometimes called mash It is the first stage below 1 K and is also used to liquefy returning 3He The still requires a few milliwatts of heat froma resistive heater to sustain evaporation The still output can drive the still heater This is a good location for a diagnostic temperature sensor 2 3 23 He Cryostat 2 3 2 3HeCryostat 17 Heat exchangers one or more heat exchangers serve to cool returning 3He rich liquid to nearthe temperature ofthe mixing chamber Also u
301. t and Lake Shore shall have no duty to defend indemnify or hold harmless you from and against any orall damages or costs incurred by you arising from the infringement of patents or trademarks or violation or copyrights by the Product 10 THIS WARRANTY IS NOT TRANSFERRABLE This warranty is not transferrable 11 Except to the extent prohibited by applicable law neither Lake Shore nor any of its subsidiaries affiliates or suppliers will be held lia ble for direct special incidental consequential or other damages including lost profit lost data or downtime costs arising out ofthe use inability to use or result of use ofthe product whether based in warranty contract tort or other legal theory regardless whether or not Lake Shore has been advised of the possibility of such damages Purchaser s use of the Product is entirely at Purchaser s risk Some countries states and provinces do not allow the exclusion of liability for incidental or consequential damages so the above limitation may not apply to you 12This limited warranty gives you specific legal rights and you may also have other rights that vary within or between jurisdictions where the productis purchased and or used Some jurisdictions do not allow limitation in certain warranties and so the above limitations or exclu sions of some warranties stated above may not apply to you 13 Except to the extent allowed by applicable law the terms of this limited warranty stateme
302. t high and low operation or each can be assigned to a different input Relay 1 Relay 2 Off On A Alarm B Alarm C Alarm D Alarm off On A Alarm B Alarm C Alarm D Alarm Manual off Manualon Follows Follows Follows Follows Manual off Manualon Follows Follows Follows Follows Mem Time InputA InputB InputC InputD eremi meme J InputA InputB f InputC InputD EE TEE Both Low High Both Low High Alarms Alarm Alarm Alarms Alarm Alarm Off Manual off relay remains in the normal state On Manual on relay remains in the active state AAlarm Relay will follow Input A alarms BAlarm Relay will follow Input B alarms Both Alarms Relay active when eitherthe High or Low Alarm is active Low Alarms Relay active only when the Low Alarm is active CAlarm Relay will follow Input C alarms High Alarms Relay active only when the High Alarm is active DAlarm Relay will follow Input D alarms 5 8 Curve Numbers and Storage Model 350 Temperature Controller FIGURE 5 6 Relay settings When using relays with alarm operation set up alarms first The relays are rated for 30 VDC and 3 A Theirterminals are in the detachable terminal block on the Model 350 rear panel In the Off mode the relay is un energized leaving the normally open NO contacts open and the normally closed NC contacts clo
303. t met when starting the autotune procedure causing the autotuning process to never actually begin then the error status will be set to 1 and the stage status will be stage OO WARMUP Input Format Example Remarks WARMUP Input Format Returned Format WEBLOG Input Format Example Remarks WEBLOG Input Returned Format Remarks 6 6 1 InterfaceCommands 157 Warmup Supply Parameter Command WARMUP lt output gt lt control gt lt percentage gt term n n nnn nn lt output gt Specifies which analog output to configure 3 or 4 lt control gt Specifies the type of control used 0 Auto Off 1 Continuous lt percentage gt Specifies the percentage of full scale 10 V Monitor Out voltage to apply to turn on the external power supply WARMUP 3 1 50 term Output 3 will use the Continuous control mode with a 5 V 5096 output voltage for activating the external power supply The Output Mode parameter and the Control Input parameter must be configured using the OUTMODE command Warmup Supply Parameter Query WARMUP output term n nnn nn lt output gt Specifies which analog output to query 3 or 4 lt control gt lt percentage gt term n nnn refer to command for description Website Login Parameters WEBLOG lt username gt lt password gt term s 15 s 15 username 15 character string representing the website username password 15 character string representing the website password
304. t temperatures For example a platinum sensor has good sensitivity at higher temperatures but it has limited use below 30 K because its sensitivity drops sharply It is difficult to determine if a sensor has adequate sensitivity over the experi mental temperature range This manual has specifications section 1 3 that include sensor sensitivity translated into temperature resolution and accuracy at different points This is typical sensor response and can be used as a guide when choosing a sensorto be used with the Model 350 The experimental environment is also important when choosing a sensor Environ mental factors such as high vacuum magnetic field corrosive chemicals or even radiation can limitthe use of some types of sensors Lake Shore has devoted much time to developing sensor packages that withstand the temperatures vacuum levels and bonding materials found in typical cryogenic cooling systems Experiments done in magnetic fields are very common Field dependence of tempera ture sensors is an important selection criteria for sensors used in these experiments This manual briefly qualifies the field dependence of most common sensors in the specifications section 1 6 Detailed field dependence tables are included in the Lake Shore Temperature Measurement and Control Catalog When available specific data on other environmental factors is also included in the catalog Temperature measurements have several sources of uncertainty that
305. tages Offset voltages affect accuracy more when the excitation is small because they are a larger percentage ofthe mea sured voltage Square wave reversing measurements allow higher amplifier gain and greater sensitivity than DC techniques 2 4 2 Excitation Modes 2 4 3 Resistance Ranges 2 4 4 Measurement Circuit 2 4 2 Excitation Modes 19 The Model 350 uses a low noise current source excitation for sensor measurements The instrument firmware is also able to simulate voltage excitation of the measured sensorto create an autorange mode The autorange mode is usually preferred because it conveniently limits the excitation power of NTC sensors asthe tempera ture decreases There are two autorange modes available 1 mV and 10 mV Resis tance range selection is different for these two voltages Autorange is available for both voltage excitations 2 4 2 1 Autorange Excitation Mode The user specifies an input voltage range that is a not to exceed setting for the instrument The instrument selects the appropriate current setting that keeps the voltage across the sensor as high as possible without exceeding the voltage range set ting Current is changed when the resistance range changes to maintain the voltage limit The autorange mode is preferred when measuring negative temperature coeffi cient materials common in cryogenic temperature sensors With voltage limited excitation power in the sensor reduces with lowering temperature P V2
306. tandard Code for Information Interchange ASCII format One start bit and one stop bit are necessary to synchronize consecutive characters Parity is a method of error detection One parity bit configured for odd parity is included in each character ASCII letter and number characters are used most often as character data Punctua tion characters are used as delimiters to separate different commands or pieces of data A special ASCII character line feed LF OAH is used to indicate the end of a mes sage string This is called the message terminator The Model 350 will accept either the line feed character alone ora carriage return CR ODH followed by a line feed as the message terminator The instrument query response terminator will include both carriage return and line feed 6 3 4 2 Message Strings A message string is a group of characters assembled to perform an interface function There are three types of message strings commands queries and responses The computer issues command and query strings through user programs the instrument issues responses Two or more command or query strings can be chained together in one communication but they must be separated by a semi colon The total com munication string must not exceed 255 characters in length A command string is issued by the computer and instructs the instrument to perform a function or change a parameter setting The format is command mnemonic gt lt space gt lt par
307. tandard sensors if possible One point SoftCal calibrations with platinum sensors have no specified accuracy Two point SoftCal calibrations for applications above 70 K are performed at liquid nitrogen 77 35 K and room temperature 305 K Accuracy for the PT 102 PT 103 or PT 111 platinum sensor is as follows 250 mK 70 K to 325 K 500 mK 325K to 1400 mK at 480 K DIN class A or class B tolerance TABLE 5 8 Three point SoftCal calibration accuracy for DT 470 SD 13 diode sensors Three point SoftCal calibrations are performed at liquid nitrogen 77 35 K room temperature 305 K and high temperature 480 K Accuracy for the PT 102 PT 103 or PT 111 platinum sensor is 250 mK from 70 K to 325 K and 250 mK from 325Kto 480 K 5 10 5 SoftCal CalibrationCurve Creation 5 10 5 SoftCal CalibrationCurveCreation 103 Once the calibration data points have been obtained you may create a SoftCal cali bration Press Curve Entry then scroll to Softcal and press Enter A list of sensortypes is displayed containing DT 470 PT 100 and PT 1000 Scroll to the desired sensortype and press Enter A list of SoftCal parameters is displayed Use the Store Location parameter to choose the user curve location in which to store the newly generated curve If desired use the Serial Number parameter to enter a serial numberforthe newly generated curve Use the Point X Temp and Point X Sensor parameters to enter c
308. te ESR Read and clear the Standard Event Status Register allowing an SRQto be generated on another command error TABLE 6 4 Programming example to generate an SRQ 6 2 6 4 Using Status Byte Query STB The Status Byte Query STB command is similar to a serial poll except it is pro cessed like any other instrument command The STB command returns the same result as a serial poll except that the Status Byte bit 6 RQS MSS is not cleared In this case bit 6 is considered the MSS bit Using the STB command does not clearany bits in the Status Byte Register 6 2 6 5 Using the Message Available MAV Bit Status Byte summary bit 4 MAV indicates that data is available to read into the bus controller This message may be used to synchronize information exchange with the bus controller The bus controller can for example send a query command to the Model 350 and then wait for MAV to set If the MAV bit has been enabled to initiate an SRQ the user s program can direct the bus controller to look for the SRQ leaving the bus available for other use The MAV bit will be clear whenever the output buffer is empty 6 2 6 6 Using Operation Complete OPC and Operation Complete Query OPC The Operation Complete OPC and Operation Complete Query OPC are both used to indicate when pending device operations complete However the commands operate with two distinct methods The OPC command is used in conjunction with bit O
309. ted cables attached to the instrument Make cable runs as short and direct as possible Higher radiated emissions are possible with long cables Do not tightly bundle cables that carry different types of signals Lake Shore www lakeshore com CRYOTRONICS Chapter 1 Introduction Chapter 2 Cooling System Design and Temperature Control 1 1 1 2 1 3 1 4 1 5 1 6 1 7 2 1 2 2 2 3 2 4 2 5 Table of Contents Product Description 6 cece eee eee e e eme e eme een 1 Application Versatility sssssssssssssssssssss I eme eme ee 2 1 2 1 Four Standard Sensor Input Channels ssssssssssssssssssseeeeeees 2 1 2 2 Three Option Cards for More Inputs and a Wider Range of Applications 2 1 2 3 Four PID Controlled OUtpUtS cece cece cece eee 2 1 2 4 Precision Temperature Control cc cece cece cece ee ee ee eee 3 Simple and Increased Productivity cc cece cece een e eee e 3 1 3 1 Three Interfaces for Remote Control 0 cece cece cece cece eee e enna ee 3 1 3 2 Simple Automation sss eee e een 3 Performance You Can Count On sssssssssssssssssssseee eee eee enn 3 1 4 1 Balanced Current SOULCE 6 cece cece cece ence eee eeeeee ee 3 1 4 2 Common Mode Reduction Circuit 0 0 c cece cece eee cece eee e eee e ee 3 1 4 8 Measurement Isolation ccc cece cece cece eee e eee eeeeeenaee 4 1 4 4 Configurable Display
310. term address term nn referto command for description INCRV Input Format Remarks Example INCRV Input Format Returned Format INNAME Input Format Example Remarks INNAME Input Format Returned Format INTSEL Input Format Remarks INTSEL Input Returned Format 6 6 1 InterfaceCommands 147 Input Curve Number Command INCRV lt input gt lt curve number gt term a nn lt input gt Specifies which input to configure A D D1 D5 for 3062 option lt curve number gt Specifies which curve the input uses If specified curve type does not match the configured input type the curve number defaults to O Valid entries O none 1 20 standard curves 21 59 user curves Specifies the curve an input uses for temperature conversion INCRV A 23 term Input A uses User Curve 23 for temperature conversion Input Curve Number Query INCRV input term a input Specifies which input to query A D D1 D5 for 3062 option curve number term nn referto command for description Sensor Input Name Command INNAME input name term a s 15 input Specifies inputto configure A D D1 D5 for 3062 option name Specifies the name to associate with the sensor input INNAME A Sample Space term the string Sample Space will appearon the front panel display when possible to identify the sensor information being displayed Be sure to use quotes
311. th sensor names If 4 Large is selected then four large character readings are displayed without sensor names If 8 Small is selected then eight small character readings are displayed without sensor names Menu Navigation Display Setup Number of Locations 2 Large 4 Large 8 Small Lake Shore www lakeshore com CRYOTRONICS 64 CHAPTER 4 Operation Model 350 Temperature Controller Input and Units each available display location has an associated Input and Units setting The Input parameter determines which sensor will be used asthe input of the displayed data The Input can be any of the four sensor inputs or None If None is selected then the display location will be blank The Units parameter determines which units to display the reading in Menu Navigation Display Setup Location 1 2 3 4 5 6 7 8 Input None Input A Input B Input C Input D Display Setup Location 1 2 3 4 5 6 7 8 Units Kelvin Celsius Sensor Min Max Sensor Name Interface Command DISPFLD LENIN NN 1 Input A 2 Input B m input C Kelvin 4 Input D 5 InputA 6 Input B 7 input C Sensor 8 Input D TABLE 4 6 Defaults m Displayed Output in the Custom Display mode the bottom half of the display is dedicated for output and control loop information for one ofthe four outputs The source ofthis information depends on the output selected for the Displayed Output parameter If the
312. the instrument Once the Model 350 is properly connected and the IP parameters prop erly configured the web interface can be opened using a web browser The web inter face should be accessible using any modern web browser but has only been tested with Microsoft Internet Explorer version 6 0 and 7 0 6 4 4 1 Connecting to the Web Interface To connect to the web interface type http followed by the IP address assigned to the Model 350 that you are attempting to connect to If connecting from a device on the same local network and a hostname is properly assigned to the Model 350 via a naming service on the network section 6 4 1 3 then the IP address can be replaced by the hostname If connecting from a device not on the same local network but on a network which is connected to the local network of the Model 350 and a hostname and a domain name are properly assigned the IP address can be replaced by the host name followed by the domain name with a dot separator between them For exam ple ifthe hostname LSCI 3500001 and the domain name yourdomain com were assigned via a naming service then typing http LSCI 3500001 yourdomain com would open the home web page of the Model 350 embedded website 6 4 4 2 Web Pages Each web page contains detailed help information in the form of tool tips You can access these tool tips by hovering the mouse pointer over the various help icons show help icon image here located throughout
313. the embedded website Home Page provides a summary of information specific to the Model 350 LakeShore S75 MCCORKLE BLVD WESTERVILLE OH 43082 61U 891 22UU INFOELAKESHORE COM Model 350 Temperature Controller Temperature Products Home Model 350 Temperature Controller Ethernet Configuration hi l ller E E Statics Lake Shore Model 350 4 channel variable heater output temperature controller Utilities Security Settings Instrument Model 350 Contact Us Description LSCI 350 Temp Controller 35000A Instrument Serial Number 35000A Option Serial Number Not Present o2 L EE Instrument Firmware Rev 11 Aa P c D Ethernet Firmware Rev 2 1 a Hostname 192 168 0 12 IP Address 192 168 0 12 MAC Address 00 40 9D 4E 68 B5 FIGURE 6 5 Model 350 home page Lake Shore www lakeshore com CRYOTRONICS 128 CHAPTER 6 Computer Interface Operation Model 350 Temperature Controller Ethernet Configuration Page provides a means of reconfiguring the Ethernet config uration parameters of the Model 350 LakeShore 575 MCCORKLE BLVD WESTERVILLE OH 43082 61U 31 22Uu INFOCLRKESHORE COM Model 350 Temperature Controller Temperature Products Home Ethernet Configuration for Model 350 Temperature cred Controller Configuration Ethernet Status Utilities cuz Security Settings Contact Us um Static IP IP Address f192 168 0 12 Subnet Mask 255 255 255 0 Default Gatewa
314. the same temperature Copper and aluminum are examples of metals that have good thermal conductivity while stainless steel does not Non metallic electrically insulating materials like alumina oxide and similar ceramics have good thermal con ductivity while G 10 epoxy impregnated fiberglass does not Sensor packages cool ing loads and sample holders should have good thermal conductivity to reduce temperature gradients Surprisingly the connections between thermally conductive mounting surfaces often have very poor thermal conductivity referto section 2 10 4 and section 2 10 5 Thermal contact area greatly affects thermal conduction because a larger area has more opportunity to transfer heat Even when the size of a sensor package is fixed thermal contact area can be improved with the use of a gasket material like indium foil and cryogenic grease A soft gasket material forms into the rough mating surface to increasethe area ofthe two surfaces that are in contact Good gasket materials are soft thin and have good thermal conductivity They must also withstand the environ mental extremes Indium foil and cryogenic grease are good examples When sensors are permanently mounted the solder or epoxy used to hold the sensor act as both gasket and adhesive Permanent mounting is not a good solution for everyone because it limits flexibility and can potentially damage sensors Much care should be taken not to over heat or mechanically stress sens
315. tiated on or temperature not within EPOR temperature is within 5 K of setpoint 5 K of setpoint Ensures that temperature is not still emperaturewasmovihg toomutht Allow the temperature to 1 Waiting for temperature to settle settling toward the setpoint or drifting p 8 settle more before initiating properly Autotune away from the setpoint Autotune Ensures that there is no temperature uw siiis E T c pe May indicate that the initial P value is too 2 Testing for temperature stability oscillation or excessive noise in the Use a smaller initial P value temperature reading high Observing system response to Control parameters are changed based System response is too slow orthe heater If not already using High 3 istoo underpowered for the system to range increase initial setpoint change onobservation Autotune heater range Waiting for temperature to settle System response is too slow to Autotune Provides a baseline for wae 4 after returning setpoint to or the new control parameters are caus Use a smaller initial P value va subsequent stages s deri original value ing instability in the control Ensures that there is no temperature nen ap System response is too slow to Autotune zs oscillation or excessive noise in the 5 Testing for temperature stability orthe new control parameters are Use a smaller initial P value temperature reading after control D od causin
316. tion 4 2 94460 26 56 Q K 38 uK 1 8 mK 5 8mK 75 3 uK 100 2720 0 024 Q K 4 2 mK 151 mK 171 mK 8 3mK 14 358900 947900 K 11K 257 uK 4 3 mK 21 1 uK Germanium GR 1400 AA with 4 2 16890 861 9 Q K 35 uK 900 uk 4 9 mK 69 6 uK 10 mv 1 4D calibration 77 3 550 0 05 Q K 2mK 83 mK 94 mK 4 mK 100 2 80 0 021 Q K 4 8 mK 175 mK 195 mK 9 5 mK 0 1 35490 12578 Q K 79 5 uK 908 uK 4 9 mK 159 uK 0 5 21880 1056 Q K 284 uK 2 7 mK 6 7 mK 568 uK TM a bl nn b coca aai 14 1779 0 198 Q K 1 5 mK 13 7 mK 18 mK 3 0mK i 4 2 15460 40 0 Q K 7 5 mK 65 4 mK 69 mK 15 0 mK 40 11990 3 41 Q K 88 mK 727 mK 803 mK 176 mK 30 8660 0 1910 K 0 5 mK 22 mK 31 mK 1 0 mK Platinum RTD PT 103 with 14J 77 20 38 Q 0 423 Q K 0 7 mK 34 mK 44 mK 1 4 mK 500 Q Full Scale calibration 300 110 35 Q 0 387 Q K 7 8 mK 140 mK 164mK 15 5 mK 500 185 6689 0 378 Q K 7 9 mK 223 mK 274 mK 15 9 mK 6 E t K t EUN 14 1 664 V 12 49 mV K 0 8 mK 13 mK 20 mK 1 6mK SION GS 77 1 028V 1 73 mV K 5 8 mK 76 mK 113 mK 11 6 mK a 300 0 5596 V 2 3 mV K 4 3 mK 47 mK 82 mK 8 7mK 500 0 0907V 2 12 mV K 4 7 mK 40 mK 94 mK 9 4mK DEATO SDAIS 14 1 6981V 13 1 mV K 0 8 mK 13 mK 20 mK 1 5 mK silicon Dise uiti 4d 77 1 0203V 1 92 mV K 5 2 mK 68 mK 105 mK 10 4 mK calibration 300 0 5189V 24mV K 4 2 mK 44 mK 79 mK 8 3 mK 475 0 0906 V 2 22 mV K 4 5 mK 38 mK 87 mK 9 0 mK NUNC 14 5 3909V 97 5 mV K 0 21 mK 6 mK 13mK 410 pK 77 14222V 124mV K 16 m
317. tion 8 6 for instructions for changing and verify ing a line fuse Model 350 Temperature Controller 3 4 3 Power Cord A WARNING A WARNING 3 4 4 Power Switch 3 5 Diode Resistor Sensor Inputs 3 5 1 Sensor Input Connector and Pinout 3 4 3 PowerCord 47 The Model 350 includes a 3 conductor power cord that mates with the IEC 320 C14 line cord receptacle Line voltage is present on the two outside conductors and the center conductor is a safety ground The safety ground attaches to the instrument chassis and protects the user in case of a component failure ACE approved power cord is included with instruments shipped to Europe a domestic power cord is included with all other instruments unless otherwise specified when ordered Always plug the power cord into a properly grounded receptacle to ensure safe instru ment operation Do not use a detachable mains supply cord with inadequate rating Position the Model 350 in such a way to enable easy access to the disconnecting device Failure to comply could result in death or injury to personnel If the power supply cord is damaged or lost it must be replaced Contact Lake Shore fora replacement to ensure proper voltage current and type of cord The power supply cord must not exceed 3 m in length The delicate nature of measurements being taken with this instrument may necessi tate additional grounding including ground strapping of the instrument chassis In these cases the operat
318. tname When using naming systems other than DNS the Model 350 cannot assign the Preferred Hostname or retrieve the Actual Hostname Domain Name A domain is a collection of network devices that are managed according to some common characteristic of its members Domains can contain subdomains which are subsets within the domain The hierarchy can contain several dot sepa rated levels which flow from right to left For example lakeshore com contains the top level domain com and the subdomain lakeshore When using the Domain Name System DNS to connect to a specific host device on a network the device s hostname is tacked onto the left of the domain name For example the www in www lakeshore com refers to the Lake Shore web server located within the internet domain lakeshore com 6 4 2 Viewing Ethernet Configuration 6 4 2 ViewingEthernetConfiguration 125 If the Model 350 is connected to a network with Dynamic DNS DDNS capability a DNS entry is automatically created using the Preferred Hostname and Preferred Domain Name parameters and the assigned IP address The Preferred Domain Name parameter can only be accessed using the NET interface command section 6 6 1 or by using the Ethernet configuration page section 6 4 2 ofthe embedded website on the Model 350 If DNS reverse lookup is enabled on the network DNS server and the DNS address parameters are correctly configured the Model 350 will perform a reverse
319. to IP are disabled or if all enabled automatic configuration methods fail To use Static IP to manually config ure the IP address subnet mask and gateway of the Model 350 set the DHCP and the Auto IP parameters to Off Refer to the paragraphs above for details on turning off DHCP and Auto IP The Model 350 will now use the Static IP Address Static Subnet Mask Static Gateway Static Primary DNS and Static Secondary DNS parameters to attempt to configure the Ethernet interface connection Refer to section 6 4 1 3 for details on DNS parameters Contact your network administrator for the appropriate Static IP parameters for your network Menu Navigation Interface Modify IP Config Static IP Valid IP Address Interface Modify IP Config Static Subnet Mask Valid Subnet Mask Interface Modify IP Config Static Gateway Valid IP Address Interface Modify IP Config Static Pri DNS Valid IP Address Interface Modify IP Config Static Sec DNS Valid IP Address 6 4 1 3 DNS Parameters The parameters discussed in this section exist to facilitate the use of the Domain Name System DNS to connectto the Model 350 using assignable names ratherthan cryptic IP addresses This functionality is provided for convenience only and is not critical to the connectivity ofthe Ethernet interface DNS Address A Domain Name System DNS is a service that translates names into IP addresses This service allows for using human readable names
320. tomatically reverse the polarity of the current source every other reading The average of the positive and negative sensor readings will cancel the thermal EMF voltage that is present in the same polarity regardless of current direction This cor rection algorithm is enabled by default for RTD sensor types but can be turned off using the Current Reversal parameter Lake Shore www lakeshore com CRYOTRONICS 68 CHAPTER 4 Operation 4 4 5 Thermocouple Sensor Input Setup Model 3060 Only Model 350 Temperature Controller The Current Reversal parameter defaults to On anytime the Sensor Type parameter is changed to PTC RTD or NTC RTD Menu Navigation Input Setup nput A B C or D Current Reversal Off or On Default On Interface Command INTYPE When a Model 3060 Thermocouple option is installed in the Model 350 a setting of Thermocouple becomes available under the Sensor Type parameter in the Input Setup menu The standard RTD sensor inputs can still be used when the Thermocou ple option is installed but the Thermocouple and standard inputs cannot be used simultaneously Refer to section 7 4 2 to install the Model 30603060 Thermocouples include a variety of commercial such as E K T and specialty types such as cryogenic Chromel AuFe Standard curves are included in the Model 350 for the types listed in TABLE 4 7 Othertypes can be used aslong as an appropriate tem perature response curve is loaded as a user cur
321. tput The remaining parameters detailed in this section dictate how the output value is determined An output configured to Monitor Out mode is not affected by the ALLOFF key as it does not have a Heater Range setting and by design is always enabled Menu Navigation Output Setup Output 3 or 4 Output Mode Monitor Out Output Setup Output 3 or 4 Control Input None Input A Input B Input C Input D Default Control Input None Interface Command OUTMODE The Monitor Units parameter determines the units of the Control Input sensor to use for creating the proportional voltage output The Monitor Out scaling parameter set tings are entered using the units chosen for this parameter Menu Navigation Output Setup Output 3 or 4 Monitor Units K C or Sensor Default K Interface Command ANALOG 5 6 1 MonitorUnits 91 5 6 1 1 Polarity and Monitor Out Scaling Parameters In the Monitor Out and Open Loop modes the unpowered analog outputs can be con figured as either unipolar 0 V to 10 V or bipolar C10 V to 10 V outputs In bipolar mode the Monitor Out 10 V setting determines the temperature or sensor value at which the output should be 10 V In unipolar mode the Monitor Out O V setting determines the temperature or sensor value at which the output should be O V The Monitor Out 10 V setting determines the temperature or sensor value at which the output should be 10 V in either unipolar or bipolar modes L
322. trol loops This section does not attempt to compete with control theory experts It describes a few basic rules of thumb to help less experienced users get started This technique will not solve every problem but it has worked for many oth ers in the field This section assumes you have worked through the operation sections ofthis manual have a good temperature reading from the sensor chosen as a control sensor and are operating Loop 1 It is also a good idea to begin at the center of the temperature range ofthe cooling system not close to its highest or lowest tempera ture Autotune section 2 15 is another good place to begin and do not forget the power of trial and error Setting an appropriate heater output range is an important first part of the tuning process The heater range should allow enough heater power to comfortably over come the cooling power of the cooling system If the heater range will not provide enough power the load will not be able to reach the setpoint temperature Con versely if the range is set too high the load may have very large temperature changes that take a long time to settle out Delicate loads can even be damaged by too much power Often there is little information on the cooling power of the cooling system at the desired setpoint If this is the case try the following allow the load to cool completely with the heater off Set Manual Output to 50 while in Open Loop control mode Turn the heater to th
323. ture Compensation Calibration Procedure Factory calibration ofthe instrument is accurate to within approximately 1 K Differ ences in thermocouple wire and installation technique create errors greater than the instrument errors To achieve the best accuracy calibrate with the thermocouple actually being used because it eliminates most sources of error If that is not possible use a thermocouple made from the same wire It is best practice to use the same material for thermocouple wires if it is at all possible it is also bestto avoid splices When splices are necessary continue the splice with the same type of material 4 4 6 Capacitance Sensor Input Setup Model 3061 Only 4 4 6 CapacitanceSensorInputSetup Model 30610nly 69 For less demanding applications a short across the input terminals will suffice Both thermocouple inputs should be calibrated even ifthey use the same type of thermo couple An appropriate curve must be selected and room temperature compensation must be turned on before calibration can be started Follow this procedure to calibrate room temperature compensation For best results the calibration temperature should be close to the measurement tem perature that requires best accuracy 1 Attach a thermocouple sensor or direct short across the input terminals of the thermocouple input See FIGURE 3 8 for polarity 2 Placethe instrument away from drafts If calibrating using a short place an accu rate
324. ture Controller amp akeShore A InPut A 1 1 Product Description 67 096 Ape aee f Off Hj an u n am cef Model 350 Temperature Controller a a a ALL OFF Co gE D 1 1 ProductDescription 1 Chapter 1 Introduction Input Setup Curve Entry Remote Local Exit Menu Remote n 9j 66 9 CO CO CO g Bhemet Con Setup Zone Stings hisce c Es C 0 CO CO a om BOO GOOD VY FIGURE 1 1 Model 350 front view Features m Ideal for use with He 3 systems and other ultra low temperature refrigeration platforms down to 100 mK m Optimized performance with Cernox RTDs m Patented low noise input circuitry enables super low excitation power for mini mal self heating and high resolution measurement m 4independent control loops and a broad range of I O configurations can elimi nate need for additional instrumentation m 4PID controlled outputs 75 W warm up heater 1 W sample heater and 2 auxil iary 1 W 10 V outputs m Proven intuitive interface m Performance assurance even at the extremes with verifiable product specifica tions m Full 3 year standard warranty The Model 350 is designed for the demands of pumped He 3 refrigerators and other ultra low and low temperature platforms It provides excellent measurement perfor mance superior control accuracy and convenient operation in a wide range of advanced research applications Whether the need is for high accuracy with mini
325. ture values below 10 K can be entered with 0 0001 resolution Temperature range for curve entry is OK to 9999 99 K Lake Shore www lakeshore com CRYOTRONICS 96 CHAPTER 5 Advanced Operation 5 9 Front Panel Curve Entry Operations 5 9 1 Edit Curve Model 350 Temperature Controller Silicon Diode DT 670 V K 475 Negative 0 00001V GaAlAs Diode TG 120 WK 325 Negative 0 00001 V Platinum 100 PT 100 Q K 800 Positive 0 001 Q Platinum 1000 Q K 800 Positive 0 01 Q Rhodium Iron RF 800 Q K 325 Positive 0 0010 Carbon Glass CGR 1 1000 log Q K 325 Negative 0 00001 log Q Cernox CX 1050 log Q K 325 Negative 0 00001 log Q Germanium GR 200A 100 log Q K 325 Negative 0 00001 log Q Rox RX 102A log O K 40 Negative 0 00001 log Q Type K 9006 005 mV K 1500 Positive 0 0001 mV Type E 9006 003 mV K 930 Positive 0 0001 mV TypeT 9006 007 mV K 673 Positive 0 0001 mV Au Fe 0 03 mv K 500 Positive 0 0001 mV Au Fe 0 07 9006 001 mV K 610 Positive 0 0001 mV Not offered by Lake Shore TABLE 5 4 Typical curve parameters Setting resolution is also six digits in sensorunits The curve format parameter defines the range and resolution in sensor units as shown in TABLE 5 3 The sensor type determines the practical setting resolution TABLE 5 4 lists recommended sen sor units resolutions Enterthe breakpoints with the sensor units value increasing as point number increases There should not
326. ually increase the overall uncer tainty ofthe measurement As seen in TABLE 2 1 the best uncertainty varies among the three sensors and their corresponding excitation ranges The best values are shaded to guide the eye The CX 1010 has a high self heating error at 30 nA so itis likely that a lower current will be preferable The GR 50 sensor can be driven with up to 300 nA but lower currents sig nificantly reduce the self heating The GR 50 s total uncertainty drops to its lowest level at 30 nA but ifthe excitation is further reduced to 10 nAthe total uncertainty increases due to the contribution ofthe instrument accuracy The RX 102B illustrates the tradeoff even clearer the total uncertainty almost doubles from 30 nA to 10 nA 2 7 3 Considerations When Measuring Ultra Low Temperatures Below 300 mK 27 5 c a S E c gt gt o fe g Z 5 T P E El id S gt 1 T D 4 eS T er Cis m 5 e oE f peo pa pan u Ew Q c ou c vr E ou 2 a f las E 9 E 5 3 5 9 Sgt 2 3 g gt so E N S E E Es z SLE 3 o 2 S Ea 24 g g E EB E E o L E 5 os ESSE 2 FEC 5 SRE JEU ee r E E E zoe s a T a 1000 10nA 40 02 10 800 0 1 rng 181 0 0412 1 0 04 rdg i 7 t tog 100mK 3546 12 578 6x10 sona 34 130 O 0 1 rng we 4 0 04 rdg 10 Q 0 1 rng x 100 0 0 1 rng 10 nA A 1 KOS On 0 0 10 140 0 04 rdg 1 4 0 0 5 4 30 Q 0 1 rng mea 30nA m
327. uires a separate temperature sensor if its temperature is different from the 3He evaporator This section explains sensor resistance measurements excitation modes resistance ranges and measurement circuits It also explains measurement speed and filtering for the Model 350 The Model 350 uses a four lead AC square wave measurement technique to achieve its accuracy with current excitations down to 10 nA The Model 350 uses current excitation because controlled current is very stable and predictable Current can also be scaled easily which is necessary to achieve low exci tation The Model 350 has 11 current settings from 1 mA down to 10 nA These cur rents have low noise and almost no DC component to self heat the sensor Precision sensor measurements use a four lead method to eliminate the effect of nominal lead resistance Excitation current is driven on one pair of leads while the resulting signal voltage is measured on the second pair Measurement errors from lead resistance are proportional to current flowing in the voltage leads Instrument voltage inputs are expected to have high impedanceto preventthe unwanted current from flowing The Model 350 has high input impedance to both normal mode volt ages created by current source excitation and common mode voltages created by induced noise on the leads Offset voltages occur in every electronic circuit both in signal amplifiers and in lead wire connections that create thermal EMF vol
328. unction or change a parameter setting When a command is issued the computer is acting astalker and the instrument as listener The format is command mnemonic gt lt space gt lt parameter data gt lt terminator gt Command mnemonics and parameter data necessary for each one is described in section 6 6 1 A terminator must be sent with every message string A query string is issued by the computer and instructs the instrument which response to send Queries are issued similar to commands with the computer acting as talker and the instrument as listener The query format is lt query mnemonic gt lt gt lt space gt lt parameter data gt lt terminator gt Query mnemonics are often the same as commands with the addition of a question mark Parameter data is often unnecessary when sending queries Query mnemonics and parameter data if necessary is described in section 6 6 1 A terminator must be sent with every message string Issuing a query does not initiate a response from the instrument Aresponse string is sent by the instrument only when it is addressed as a talker and the computer becomes the listener The instrument will respond only to the last query it receives The response can be a reading value status report or the present value of a parameter Response data formats are listed along with the associated queries in section 6 6 1 Lake Shore www lakeshore com CRYOTRONICS 108 CHAPTER 6 Computer Interface Operation
329. uration DHCP does have the disadvantage of not necessarily pre serving the IP address through a device reconfiguration as well as the possibility of being automatically reconfigured when the DHCP lease expires Contact your net work administrator to find out the DHCP lease policy on your network To use DHCP to automatically configure the IP address subnet mask and gateway of the Model 350 simply connect the Model 350 to a network that provides a DHCP server and set the DHCP parameter to On By default the DHCP feature of the Model 350 is On Menu Navigation Interface Modify IP Config gt DHCP gt Off or On Auto IP Auto IP is a method of automatically configuring the IP address and subnet mask parameters of Ethernet devices on a link local network This configuration is performed by the Model 350 and does not require any external device Auto IP is defined in RFC 3927 Dynamic Configuration of IPv4 Link Local Addresses and can be found at The Internet Engineering Task Force website at www ietf org The auto matically configured address will be in the link local address group of 169 254 1 0 to 169 254 254 255 This group is reserved for independent local networks that do not connect to other networks This method chooses an IP address that is not already active on the network which eliminates IP address conflicts A gateway address is not applicable when using Auto IP since the purpose of a gateway address is to 6 4 1 Et
330. urve from standard curve 1 and saves it in user curve 21 Control Setpoint Command SETP output value term n tnnnnnn lt output gt Specifies which output s control loop to configure 1 4 lt value gt The value for the setpoint in the preferred units of the control loop sensor SETP 1 122 5 term Output 1 setpoint is now 122 5 based on its units For outputs 3 and 4 setpoint is only valid in Warmup mode Control settings that is P 1 D and Setpoint are assigned to outputs which results in the settings being applied to the control loop formed by the output and its control input Control Setpoint Query SETP lt output gt term n lt output gt Specifies which output to query 1 4 lt value gt term tnnnnnn refer to command for description Lake Shore www lakeshore com CRYOTRONICS 156 CHAPTER 6 Computer Interface Operation SRDG Input Format Returned Format Remarks TEMP Input Returned Format Remarks TLIMIT Input Format Example Remarks TLIMIT Input Format Returned Format TUNEST Input Returned Format Remarks Model 350 Temperature Controller Sensor Units Input Reading Query SRDG input term a input Specifies which input to query A D D1 D5 for 3062 option lt sensor units value gt term tnnnnnn Also see the RDGST command Thermocouple Junction Temperature Query TEMP term junction temperature term nnnnn Tem
331. user curve Please ensure the curve number you are writing to is correct before proceeding with the copy curve operation 1 Toperform the Copy Curve operation press Curve Entry scroll to Copy Curve then press Enter 2 Scroll to the desired curve to copy and press Enter A list of user curves is dis played Scroll to the desired user curve location to copy to and press Enter Choose Yes at the confirmation message to finalize the operation 5 Tocancelthe operation either choose No to the confirmation message or press Escape Jew Menu Navigation Curve Entry Copy Curve gt 1 59 gt 21 59 Interface Command No interface command directly corresponds to the copy curve operation You can use the CRVHDR and CRVPT commands to read curve information from one curve location and write that information to another curve location Lake Shore www lakeshore com CRYOTRONICS 100 CHAPTER 5 Advanced Operation 5 10 SoftCal 5 10 1 SoftCal With Silicon Diode Sensors Model 350 Temperature Controller The Model 350 allows you to perform inexpensive sensor calibrations with a set of algorithms called SoftCal The two SoftCal algorithms in the Model 350 work with DT 400 Series silicon diode sensors and platinum sensors They create a new tem perature response curve from the standard curve and known data points that you entered The new curve loads into one ofthe user curve locations 21 to 59 in the instrument
332. utility used for reading temperature curves Launch EN from a file to the Model 350 or from the Model handler utility 350 to a file Contact Us Ethernet Firmware Updater Java utility used for updating the firmware that implements the Model 350 Ethernet interface fe Launch Ethernet including the embedded website and the Java p utility applications Note that this application firmwareupdater does not update the Model 350 instrument firmware Instrument Configuration Backup Utility Java utility used for exporting the current AN Export x Import configuration of the Model 350 to a file or config config importing a saved configuration to the Model 350 from a file FIGURE 6 8 Utilities page Security Settings provides a means of changing the website security settings by allowing the user to enter a new username and password for the website or to remove password protection from the website The username and password parame ters are available for viewing and editing from the front panel under the Modify IP Config submenu of the Interface menu Password protection only protects access to the embedded web pages and does not pro vide any kind of security for TCP Socket access section 6 4 3 The website username and password are available from the front panel menu and there fore can easily be obtained by anyone with access to the Model 350 front panel Contact Us provides information regarding how to contact representatives o
333. ve Specifies which curve to query 1 59 index Specifies the points index in the curve 1 200 units value gt lt temp value term nnnnnn rnnnnnn refer to command for description Returns a standard or user curve data point Lake Shore www lakeshore com CRYOTRONICS 144 DFLT Input Remarks DIOCUR Input Format Remarks DISPFLD Input Format Example Remarks DISPFLD Input Format Returned Format Model 350 Temperature Controller CHAPTER 6 Computer Interface Operation Factory Defaults Command DFLT 99 term Sets all configuration values to factory defaults and resets the instrument The 99 is included to prevent accidentally setting the unitto defaults Diode Excitation Current Parameter Command DIOCUR input excitation term a n input Specifies which input to configure D2 D5 only for the 3062 card excitation gt Specifies the Diode excitation current 0 10 pA 1 1 mA The 10 pA excitation current is the only calibrated excitation current and is used in almost all applications Therefore the Model 350 will default the 10 pA current set ting any time the input sensor type is changed in order to prevent an accidental change If using a current that is not 10 pA the input sensor type must first be config ured to Diode INTYPE command If the sensor type is not set to Diode when the DIOCUR command is sent the command will be ignored Custom Mode Display Field Co
334. ve Representative thermocouple specifications are given in TABLE 1 3 The Model 350 provides one thermocouple range and no excitation because thermocouples do not require it Internal room tem perature compensation is included for convenience section 4 4 5 2 and should be calibrated before use Room temperature compensation is enabled by default but can be turned off if external compensation is being used Menu Navigation Input Setup nput C or D Sensor Type gt Thermocouple Interface Command INTYPE 4 4 5 1 Internal Room Temperature Compensation Room temperature compensation is required to give accurate temperature measure ments with thermocouple sensors It corrects for the temperature difference between the instrument thermal block and the curve normalization temperature of 0 C An external ice bath is the most accurate form of compensation but is often inconvenient The Model 350 has internal room temperature compensation that is adequate for most applications You can turn internal compensation on or off It oper ates with any thermocouple type that has an appropriate temperature response curve loaded Room temperature compensation is not meaningful for sensor units measurements Room temperature compensation should be calibrated as part of every installation section 4 4 5 2 Menu Navigation Input Setup nput C or D 3Room Compensation Off or On Default On Interface Command INTYPE 4 4 5 2 Internal Room Tempera
335. ve Product is shipped freight prepaid back to Lake Shore Lake Shore will at its option either repair or replace the Product if itis so defective with out charge for parts service labor or associated customary return shipping costto the Purchaser Replacement for the Product may be by either new or equivalent in performance to new Replacement or repaired parts or a replaced Product will be warranted for only the unexpired portion ofthe original warranty or 90 days whichever is greater 2 Lake Shore warrants the Product only if the Product has been sold by an authorized Lake Shore employee sales representative dealer or an authorized Lake Shore original equipment manufacturer OEM 3 The Product may contain remanufactured parts equivalent to new in performance or may have been subject to incidental use when it is originally sold to the Purchaser 4 The Warranty Period begins on the date of Purchaser s physical receipt of the Product or later on the date of operational training and verification OT amp V ofthe Product ifthe service is performed by Lake Shore provided that if the Purchaser schedules or delays the Lake Shore OT amp V for more than 30 days after delivery then the Warranty Period begins on the 31st day after Purchaser s physical receipt of the Product 5This limited warranty does not apply to defects in the Product resulting from a improper or inadequate installation unless OT amp V services are performed by Lake S
336. ver removal 3 Use a small Phillips screwdriver to remove the two top cover screws and one rear bottom screw FIGURE 8 10 4 Remove the rear plastic bezel The cover is tracked Slide the top cover to the rear onthe track to remove it 8 12 Enclosure Top RemoveandReplace Procedure 175 Follow this procedure to install the top enclosure 5 6 7 8 9 Slide the top panel forward in the track provided on each side ofthe unit Use a small Phillips screwdriver to replace the two top cover screws and 1 rear bottom screw Use the hex driverto replace the two screws on the side ofthe top covers Replace the rear plastic bezel by sliding it straight into the unit Tighten the two rear bottom screws 10 Replace the power cord in the rear of the unit and set the power switch to On wu o J12 option em connector z E or JMP1 FIGURE 8 11 Location of internal components Lake Shore www lakeshore com CRYOTRONICS 176 CHAPTER 8 Service 8 13 Record of TABLE 8 8 and TABLE 8 9 describe the updates made to the temperature controller in Updates Made to each version the Firmware Instrument TEE firmware version Model 3062 scanner option card support 1 3 Added sensor name units for custom display mode TABLE 8 8 Instrument firmware updates Ethernet le firmware version 1 1 Instrument configuration backup utility added 20 Chart
337. y 192 168 0 1 Primary DNS 0 0 0 0 Secondary DNS 0 0 0 0 Preferred Hostname LSCI 350 Preferred Domain Description LSCI 350 Temp Controller 35000A 7 FIGURE 6 6 Ethernet configuration page Ethernet Status Page provides status and statistics related to the current Ethernet connection LakeShore 575 MCCORKLE BLVD WESTERVILLE OH U30S2 61U 831 22uu INFOELAKESHORE COM Model 350 Temperature Controller Temperature Products Ethernet Status for Model 350 Temperature Controller Home Ethernet Configuration Ethernet Status Hb UNE 13 Iz 9 Utilities Ethernet Speed 100Mbps Security Settings Contact Us Ethernet Duplex Mode Full Duplex Total Packets Received Since Power on 1910 Total Packets Sent Since Power on 156 FIGURE 6 7 Ethernet status page 6 5 Utilities 6 5 Utilities 129 Utilities Page provides links to launch the embedded curve handler application the embedded Ethernet firmware updater and the instrument configurator backup utilities LakeShore 575 MCCORKLE BLVD WESTERVILLE OH 43082 614 891 2244 NFOELRKESHORE COM Model 350 Temperature Controller Temperature Products Home Utilities for Model 350 Temperature Controller Ethernet Configuration Ethernet Status Chart Recorder Launch chart e Java utility used for charting and logging data il Utilities toni the Modal 350 p recorder utility Security Settings Curve Handler Java
338. y Setup Display Mode Four Loop All Inputs Mode Custom Input A Input B Input C Input D Default Custom Interface Command DISPLAY 4 3 1 1 Four Loop Mode Four Loop mode provides a limited amount of information about each ofthe four sen sor inputs and the associated control loops Each quadrant of the display is dedicated to one sensor input and the associated loop if applicable The top line of each quad rant contains the input letter A B C or D followed by the user assignable sensor name The sensor readings are presented just below the sensor name in the large character format for easier viewing from a distance The sensor reading is displayed in the units assigned to the respective sensor input s Preferred Units setting which can be found underthe Input Setup menu section 4 4 If the inputis assigned asthe Con trol Input ofa control loop then the control Setpoint and Heater Output parameters are displayed under the sensor reading If the output is in Open Loop mode then the Setpoint parameter is not shown Menu Navigation Display Setup Display Mode Four Loop Mode Interface Command DISPLAY 4 3 1 2 All Inputs Mode All Inputs mode provides a limited amount of information about each of the sensor inputs Similarto the Four Loop mode each quadrant of the display is dedicated to one sensor input with the input letter being displayed followed by the user assign able input name The sensor reading is displayed i
339. y not con trol well atanothertemperature While nonlinearities exist in all temperature control systems they are most evident at cryogenic temperatures When the operating tem perature changes the behavior of the control loop the controller must be retuned As an example a thermal mass acts differently at different temperatures The specific heat of the load material is a major factor in thermal mass The specific heat of materials like copper change as much as three orders of magnitude when cooled from 100 K to 10 K Changes in cooling power and sensor sensitivity are also sources of nonlinearity The cooling power of most cooling sources also changes with load temperature This is very important when operating at temperatures near the highest or lowest tem perature that a system can reach Nonlinearities within a few degrees of these high and low temperatures make it very difficult to configure them for stable control If dif ficulty is encountered it is recommended to gain experience with the system at tem peratures several degrees away from the limit and gradually approach it in small steps Keep an eye on temperature sensitivity Sensitivity not only affects control stability but it also contributes to the overall control system gain The large changes in sensi tivity that make some sensors so useful may make it necessary to retune the control loop more often For closed loop operation the Model 350 temperature controller uses an a
340. yte Reglster i osos d pein IRR REA TER ERE RE ERPREHNS 113 6 2 6 2 Service Request Enable Register sss 114 6 2 6 3 Using Service Request SRQ and Serial Poll sususeuuee 114 6 2 6 4 Using Status Byte Query STB sssssssssss 115 6 2 6 5 Using the Message Available MAV Bit ssssssssssssse 115 6 2 6 6 Using Operation Complete OPC and Operation Complete Query FOPC ccc cece cece cece eens eee 115 6 3 WSB REA CE comede cee end cae E EEE EE EAE AEE EAA 116 Lake Shore www lakeshore com CRYOTRONICS 6 3 1 Physical Connection eet RR E oo YI a Ep 116 6 3 2 Hardware SUPPONE a iu ied per EE HEREDI ad eX UD RI 116 6 3 3 Installing the USB Driver 116 6 3 3 1 Installing the Driver From Windows Update in Windows 7 and Vista sssssssssssssssssss teen eens 116 6 3 3 2 Installing the Driver From Windows Update in Windows XP 117 6 3 3 3 Installing the Driver From the Web 00 cece cece eens 117 6 3 3 3 1 Download the driver 0 00 cece cece ee ee eee eens 117 6 3 3 3 2 Extract the driver 2 0 0 0 cece cece cece eee e eens 117 6 3 3 3 3 Manually install the driver esses 118 6 3 3 4 Installing the USB Driver from the Included CD 119 6 3 4 COMMUNICATION esis sco na elias rpe v cU Ua ERI ER AAEE REE A 119 6 34 1 Character Format 25 eere be a Re ex ERE Ca 120 6 3 4 2 Message SITTINGS isses eese a per ERR ERI H

350 Manual - Lake Shore Cryotronics, Inc.

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