I am currently working on a project with the thermocouple simulator from ueidaq DNC-378.
The main problem I face is that, my values are not constant (in the given range).

I monitored the temperature curve of 1350 degree C. At start up the values are pretty much on point. After some time the values drift away to up to 3 degrees C.

My stup are this devices:
https://www.ueidaq.com/de/products/single-slot-data-acquisition-and-control-cube-with-powerpc-cpu
https://www.ueidaq.com/de/products/8-channel-thermocouple-simulator

The cable has a length of 3 meters, without a shild and is relative isolted from any other electric device.
The CJC is disabled. In the calibration room is a constant temperature of 25 degree C.

Has anyone an idea why this problem ocures?

Tanks in advance!

 

How long, for what period of time, did you let the simulator/calibrator and the device under test stabilize under powered conditions in the area where the calibrator is used?

I've seen most stuff take a minimum of 10 minutes and usually closer to 20 minutes to stabilize. The electronics must warm to operating temperature or the output will drift until the electronics are warmed up.

 

Sometimes calibrators have open thermocouple detection circuits that send small pulses to detect if the thermocouple is open. On some calibrators you can disable this open thermocouple detection. This can influence the measurement you connect to the simulator.
Please try to find this setting and disable it. Then check again.