Thermocouples and USB DAQ 6221

[rnabiophys]

Hi,

I am trying to connect various thermocouples to a USB 6221 DAQ. I am having issues as to the readings. Some times the reading are reasonable and stable but after short periods the

temperature will saturate to some large or small value. I am using k-type thermocouples. At first I thought there was some type of interference but I have also tried the thermocouples

with an newer X-series DAQ and it works just fine with no issues. Is the USB-6221 suited for such thermocouples or am I forgetting some type of additional required equipment, i.e.

CJC?

Thanks

-Wil

[rnabiophys]

Has anyone had issues with k-type thermocouples and USB 6221 DAQ?

[MilanR]

Hi rnabiophys,

Have you tried connecting a known signal source to the analog input of the device and seeing if the expected result is given? You could try connecting something simple like a 1.5 Volt AA battery or something more precise such as a function generator with a known signal to verify that the USB-6221 analog input channels are functioning properly.