NI 9211 Thermocouple Inaccurate Reading

[prashn]

I've verified that the thermocouples are working with a datalogging thermometer, so I agree the problem is with the 9211 modules themselves. 

[NIquist]

I'm pretty sure your thermocouples are wired backwards.

Try using NI-MAX and set up a super simple 1 thermocouple, 1 sample per second collect.  Try holding the thermocouple in your hand and see if the response changes.  Make SURE you have the thermocouple wired correctly.  Yellow is positive and RED is NEGATIVE (that confuses many people since red is usually positive).

[StevenD]

As well as trying some of the advice above, I found a page that says the cDaq you have is not compatible with the most recent version of NI DAQmx.

https://www.ni.com/en-us/support/documentation/compatibility/17/devices-and-modules-no-longer-suppor... 

You can see what version of NI-DAQmx you have in MAX under software. You can also download older version (follow the links at the bottom of the linked page)

[prashn]

Hello, 

Thanks for your further advice. I have ensured that my terminals are wired correctly (yellow being positive and red being negative). I have verified that I have the most recent version of NI DAQmx that is compatible with my chassis (17.5). However, I still see the same issue. Holding the thermocouple results in a lower temperature (which it shouldn't) and measuring the ice water bath causes the aforementioned spike to 50°C. 

[NIquist]

Sorry for not getting back sooner.  I was really sure that your wiring was backwards because I plugged in my own thermocouple backwards, put it in an ice bath and read 50 degrees.  Removing it from the ice and warming it in my hand resulted in the reading going down just like you described.  This is weird but maybe you just have to wire it backwards and verify it's correct with a few known temperatures.  I can't explain why the 9211 would do this though.  I've used them a lot and never seen this effect.  🤔