Measure 104C at ambient temp from thermocouples connected to SCXI 1303

[jefska]

Using a Labview 6.1 program I'm try to measure room temperature using typeJ thermocouples but my readout says 104C.  The TCs are connected via a SCXI-1303 Isothermal board that is mounted in a SCXI 1000 chassis.  Two days ago the TCs were measuring correctly and now something went wrong.  I have no documentation on this test system and I'm new to the application so maybe there is something I'm doing wrong.  Can anybody help?

Jeff

[devchander]

In your LabVIEW program, check what have you selected as source for cjc channel

SCXI-1303 connector block has a thermistor type CJC

Just select that and check your temperature reading

[jefska]

Devchander,

Thanks for the reply but I’m not seeing in the software an input for the CJC channel.  If I open MAX and look at the TC properties I see the CJC source set to “Built-In”.  Does this take the place of having this set in the LV program?

Regards

[devchander]

To set in Labview, after chossing thermocaple instance of Create virtual channel function, you can set cjc source as built in

see attached pic

[jefska]

devchander,

Unfortunately the DAQ driver is version 6.9 not DAQmx.  When testing the readout of the thermocouples from MAX I get the same reading of 104C which I think eliminates it being a labview issue.  Any other ideas are much appreciated.

Thanks,

Jeff