Problem with Thermocouples

[SPR123]

Hi, 

i have some problems with Thermocouples.

Here is a picture of the signals.

My config:

I use Signal ExpressManager DAQ with a 9212 and a 9213 modul.

My sample rate is 50Hz (fast measuremant)

Yellow, green, red and cyan are Type N (connected at 9212 module)

Purple, blue and orange are Type K (connected at 9213 module)

CJC: intern

The wire is about 20 meter long (10 meter Thermocouple and 10 meter compensating wire)

Problems:

1.) The yellow and the orange signal have a really high oscillation.

2.) The thermocouples are all on the same position so they all should show nearly the same value but there is a offset between the Type K and Type N thermocouples

3.) The third strange thing is, if i start the recording (11:45:29,991), there is a big jump in the signal.  

I hope u have some suggestions to improve my measuremant.

Thank you.

[n_dakota]

It looks like some amplification/scaling issue. Did you manage to solve it?

[SPR123]

I managed to solve the problem with the oscillation.

But i still have the problem with the big offset between Type N and Type K thermocouples.

There is also a Offset between the Type N thermocouples.

All the Thermocouples are fixed on an aluminum plate and if i measure the temperature of the thermocouples with a Fluke portable measuring Instrument, the thermocouples give the same value.

maybe u have some suggestion

Thank you