LTC Temperature Controller Set-up ProcedureThis page describes the set up of a cryostat for operation with the LTC controller and the SET_CONDUCTUS program.
PhilosophyWith the present system, we try to achive maximum flexibility in setting up and operating any cryostat/controller combination. For proper operation, four parts need to be set up correctly:
1. Sensor Calibration Tables1.1 Sensor Calibration Tables ArchiveLocated on NT Domain LMU group disk\\PSI10\G_1610\Temperature SensorsA separate directory for every sensor class exists: CGR1 Carbon-Glass Resistance Sensors CX10 Cernox Resistance Sensors PT1 Platinum-100 Resistance Sensors STANDARD Standart Curves (e.g. Standard Curve 10 for Silicon Diode Sensors) TG120 GaAlAs Diode SensorsDecommissioned (dead, burned, etc.) sensors are stored in the respective [.OLD] subdirectories. For each Calibration Table, two ASCII file versions are available: .TAB Raw Table as supplied by manufacturer .LTC Table for download to LTC controller with SET_CONDUCTUS, fitted with all necessary parameters and control characters. 2. LTC ControllerIf group logical CONDUCTUS_USER is defined as$ DEFINE /GROUP CONDUCTUS_USER MASTERcalibration tables may be downloaded, cleared or shown interactively when Modify/Set Device/Conductus is selected in the MODAS run control menu. $ DEASSIGN /GROUP CONDUCTUS_USERhides this functionality. 2.1 Installing Temperature Calibration Tables2.1.0 Check the Calibration Tables available in the LTC ControllerCheck these tables either manually or remotly by running the command
procedure: 2.1.1 Downloading Temperature Calibration Tables
2.1.2 Updating the LTC Look-Up Table
2.1.3 Updating the Sample Holders Look-Up Table
2.2 Installing PID Tables2.2.1 Creating PID Tables
2.2.2 Downloading PID TablesDownload your table using the DCL command@ED:[COM]SET_CONDUCTUS DOWNLOAD PIDTABLE 'PID Table Name'.PID 'PID Table Index'Example: @ED:[COM]SET_CONDUCTUS DOWNLOAD PIDTABLE TEST_PID.PID 1downloads the PID Table ED:[DAT.LTC]PID_TABLE.PID as PID Table 1 to the LTC controller. Verify the PID table values stored in the LTC controller memory before setting the controller to control mode the first time! 2.3 Setting the Filter TimeRemember to set the appropriate Filter Time for your system manually at the LTC controller (Setup - Display - Setup Input Filter).
2. LTC Controller Memory Look-Up TableThe LTC Controller Memory Look-Up Table LTC_'Serial Number'.TAB in ED:[DAT.LTC] reflects for every single LTC controller the contents of the Calibration Tables and PID Tables memory and some other parameters like the device GPIB address.See an example of a LTC Controller Memory Look-Up Table. When installing a cryostat sytem, make sure the Memory Look-Up Table for the LTC controller in use is located in ED:[DAT.LTC] of your area machine and precisely reflects the contents of the memories.
3. Sample Holders Look-Up TableThe Sample Holders Look-Up Table ED:[DAT.LTC]SAMPLE_HOLDERS.TAB defines all existing cryostats/sample holders and their respective Control Modes in one file. It containes:
When installing a cryostat sytem, make sure SAMPLE_HOLDERS.TAB is located in ED:[DAT.LTC] of your area machine and up to date. 3. Control Modes3.1 Updating a Control ModeThis applies if you have replaced a control sensor.3.1.1 Updating the Sample Holders Look-Up TableUpdate the appropriate Control Mode for your cryostat/sample holder in ED:[DAT.LTC]SAMPLE_HOLDERS.TAB.3.2 Creating a new Control ModeThis applies if you have introduced an additional control sensor and/or heater or if you want to pair a control sensor with a different heater.3.2.1 Extending the Sample Holders Look-Up TableExtend the Control Modes for your cryostat/sample holder in ED:[DAT.LTC]SAMPLE_HOLDERS.TABAppendix A: Calibration Table File Names and Sensor NamesNote that Calibration Table File Names and Sensor Names are not identical. Sensor Names, as they appear in the .LTC versions of the Calibration Table Files, on the LTC controller and in the SAMPLE_HOLDERS.TAB Look-up Table carry the package type as additional parameter, if applicable.The Calibration Table File Names follow the scheme: 'Short Sensor Type Code'_'Serial Number'.'File Type'The Sensor Names follow the scheme: 'Full Sensor Type Code''Package Type Code'_'Serial Number' Sensor Type CodesShort Full Type CGR15 CGR1500 CGR-1-500 CGR11 CGR11000 CGR-1-1000 CGR12 CGR12000 CGR-1-2000 CX103 CX1030 CX-1030 CX105 CX1050 CX-1050 PT111 PT111 PT-111 TG120 TG120 TG-120See manufacturer's literature for specifications. Package Type CodeCU LR P SDSee manufacturer's literature for specifications. Sensor Serial NumberSensor Serial Number, typically starting with a one-letter code followed by 4- to 5-digit numbers.Sensor Class Code Typical no. of digits following CGR C 5 DT D 5 PT P 5 CX X 5 TG-120 none 4 File Type.TAB Raw Table as supplied by manufacturer .LTC Table for download to LTC controller, fitted with all necessary parameters and control characters.Most Calibration Table files are created by means of OCR from the hard copy of the manufacturer's calibration table and have been carefully checked for errors. However, typos are not to 1O0% excluded... |