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Instructions for Using LSCURVES and the Breakpoints Files for Lake Shore Calibrated Temperature Sensors to Program Lake Shore Temperature Controllers

The LSCURVES program is a DOS replacement for all versions of the DUMP program previously supplied by Lake Shore Cryotronics for transferring data for our calibrated temperature sensors into Lake Shore temperature monitors and controllers. LSCURVES has additional functionality not found in any version of DUMP: Click here to download the DOS Software: LSCurves.exe.


  • LSCURVES is capable of loading data into any of the following Lake Shore Temperature Controllers: 81C, 82C, 91C, 93C, 218, 234, 321, 330, and 340.
  • LSCURVES can load data using a PC RS-232 serial interface (must be COM1 or COM2) or a National Instruments PCII or PCIIA GPIB interface. The GPIB board in the computer must be configured as GPIB0; the instrument is accessed by specifying the IEEE address (factory default is 12) instead of the configured device name as with the old DUMP program. In order to load curves over the GPIB interface using the LSCURVES program, the DOS GPIB driver MUST be installed on the user's computer.


  • Please DO NOT extract the files from the curvehandler.CAB file.LSCURVES confirms the instrument model with the "*IDN?" query for newer Lake Shore instruments, checks older models by using a query for configuration data.
  • LSCURVES reads the instrument's stored curve data to determine the next available curve location for data storage, although you are permitted to overwrite existing user-stored or factory-stored curves (but not the permanently installed standard curves) if you choose. 
Four data files are provided with each calibrated sensor from Lake Shore along with the program LSCURVES.EXE and the file LSCURVES.TXT containing these instructions. The data files will usually consist of the sensor's serial number with four different file extensions: .91C, .330, .34A, and .340. The LSCURVES program does not use the file name or extension to identify the data format but instead checks the contents of the file to make sure the data is compatible with the instrument.
The .91C file is the older "data string" file format consisting of a single long character record which is the concatenation of the curve header information and the breakpoints list. This file is the same format as those used by the different versions of the DUMP program. These files may be loaded into any of the instruments listed above except for the Model 340 temperature controller, except that the Model 321 and 330 temperature controllers will only accept curves for "linear" devices (diodes, platinum or rhodium-iron resistors, thermocouples are o.k.; germanium, carbon glass, Cernox, and ruthenium oxide are NOT compatible with the 321 or the 330). This file is included for backward-compatibility with existing customer programs and Lake Shore test programs which require the old format. Old files in the "data string" format already in the possession of customers may be used with LSCURVES provided that they are re-named to have a .91C file extension.
The .330 file is a more "nicely" formatted breakpoints table which contains the same information as in the .91C file, but is more easily read and understood using a text editor. LSCURVES can also read and load data from the .330 files into Lake Shore temperature controllers.
The .34A and .340 files are usable only with Model 340 temperature controllers. The .34A file format is an older one included for compatibility with existing customer programs and Lake Shore test programs which require this file format. The .340 files are "user-readable" text files which contain all of the same information as the .34A files; both formats can be read and loaded into Model 340 temperature controllers by LSCURVES. The Model 218 Temperature Monitor uses the same file format as the Model 340 Temperature Controller.
When the LSCURVES program is started, copyright information and a brief description of the program are displayed. Below that the user is prompted to press a key: F1 to select GPIB instrument communication, F2 to indicate RS-232 communication, or Esc to quit.
If GPIB communication is selected, the user is prompted for the instrument's address and the program attempts to initialize the GPIB0 interface and the device at the selected address. If RS-232, the user is prompted for the COM port (1 or 2).
Next the user is asked to specify the instrument model. If RS-232 communication has been specified, the user then must specify the baud rate for communication from a list of the valid values for the designated instrument. LSCURVES then tries to initialize the port. If the GPIB board is not properly configured or the wrong COM port or baud rate has been entered, the program may hang at this point; if this happens, you must re-set the equipment and re-check the configuration parameters.
After successful port initialization the user is prompted for the instrument model. LSCURVES tries to confirm the identification; newer Lake Shore instruments respond to the "*IDN?" query with positive identification of the instrument model; the older instruments models (81C, 82C, 91C, 93C) cannot be distinguished from each other at this point but are asked for interface configuration information (the "W2" query) to confirm that they behave as one of these controllers should.
After the temperature controller is initialized the user is given the opportunity to specify print options. If the Enter key is pressed without changing the print options, LSCURVES will try to print the CalCurve configuration sheets to a generic ASCII printer attached to LPT1. The user may specify LPT2 or give the path for a network printer. In addition, if the printer supports the Hewlett-Packard Printer Control Language (Version 5 or later), a "nicer" print format is available for the configuration sheets.
After selecting print options, the user is prompted for a file name containing curve information to be transferred. Any valid directory path may be included with the file name. The file name is not required to end with the file name extensions mentioned above since LSCURVES reads the data file to ensure that all required information is present in the designated curve format.
Next, LSCURVES reads the instrument's stored curve information to determine the next available curve location. The user is prompted for a curve location and the program re-checks to find out if that location is currently occupied by another curve. The user is permitted to overwrite an existing curve if it is not one of the permanently installed standard curves, but a warning and an additional prompt are displayed to confirm that you want to over- write.
The data as sent to the instrument is displayed on the computer screen, then the program attempts to read back and display the curve data from the instrument. Note that RS-232 curve programming takes longer than GPIB communication because the interface is slower and because the data must be broken down into smaller pieces to create the curve in the instrument. A Model 340 temperature controller takes several seconds to permanently update the "curve flash" before the curve may be read back.
After the curve is read back from the instrument and displayed, LSCURVES asks whether the user wishes to print the configuration information for the CalCurve just installed, using the previously entered print options. At this point you may press Y to get a printout or N if no printout is desired. Next, LSCURVES asks whether the user wants to transfer another curve file. Pressing Y will cause LSCURVES to prompt the user for another file name. Pressing N will end the program.
If you have questions or problems regarding using LSCURVES, please contact or please call (614) 891-2244.l to request the assistance of a service engineer.
Revision History: Version 3.0, Revision A of LSCURVES (effective date 6/30/99) added functional support for the Model 321 Temperature controller, also fixed a problem with converting the contents of the .330 data files into the proper format for dumping the curve to the instrument, and corrected a problem with programming a serial instrument at 300 baud.