PCI-4351 Measurements Are Incorrect When I Enable the Built-in CJC SensorHardware: Modular Instruments>>Digital Multimeters (DMM)>>TBX-68
Problem: I have a PCI-4351 that I am using with a TBX-68T terminal block to measure K Type Thermocouples. I can see the PCI-4351 without problem in the Windows Device Manager and in Measurement and Automation Explorer (MAX). However, when I open a Traditional NI-DAQ Test Panel in MAX, where channels 2-10 are reading the thermocouples, and I select the built-in CJC option, I read 0 degrees C instead of room temperature as I would expect. When I select user input for the CJC options and put in approximate CJC values, the test panel returns temperatures that I expect to see. Solution: There is a note on page 13 of the TBX-68T Installation Guide, linked below, which states that in order to measure the CJC sensor when you are not using the TBX-68T’s current excitation source, you need to make sure that the TBX-68T's S1 and S2 slide switches are in the "OFF" position. This will make sure that the proper connections are made to read the room temperature values. After doing this, the test panel should return the correct readings.
Related Links: Product Manuals: CB-27T, TBX-68T, AND CB-68T Isothermal Terminal Blocks Installation Guide Knowledge Base 2RCIL32H: How to Verify Cold Junction Compensation Readings Attachments:
Report Date: 08/28/2008 Last Updated: 08/28/2008 Document ID: 4ORE279G |
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