12-01-2020 02:21 PM
Hello,
I've been trying to use k-type thermocouples to measure thermal cycles in welds, but it seems that the temperature readings are significantly lower than the actual temperature (30-50 degrees C). I'm using an NI 9213 module with the DAQmx block. Is there a way to calibrate the thermocouples, and if so, how? I've attached screen shots of the block diagram.
12-07-2020 04:26 AM
Well, the TC will report the temperature he feels, that migth or migth not be the temperature of interest 🙂
30 deg offset could be a false cold junction (CJ) compensation.
If you shortcut the TC input with a short wire , you should read the CJ temperature.
A calibration is just a comparison of your setpoint (temp) and the readout.
Depending on the number of calibration points you have, you can do a compensation of the read value.
like: one point: offset from cal and use the slope of the TC standard
two and more points allow a polynominal correction.