SCXI calibration

[New-guy]

Now I try to using SCXI-1112's built in sensor to measure outside temperature which is measured by thermocouple,through DAQmx I can define the input terminal and sensor terminal in SCXI-1112, I think I have done the sensor calibration, but when the system runs, the temperature drift largely from -20 - 890 degree, it seems it doesn't calibrate. I don't know why it changed so largely? have I completed the cold junction calibration or not? from other documents it seems I need calibrate reference coltage, and so on. please give me suggestion. thanks.
newguy

[Russell]

Hmmm, a temperature drift between -20 - 890 degrees doesn't sound like a calibration issue. Sometimes accidentally scanning the wrong channel which has nothing connected to it will show a reading that drifts like that.

Now I'm a little unclear about how you are trying to measure the outside temperature. Are you trying to read a thermocouple that is connected to the SCXI-1112? Or are you just trying to read the buil-in CJC sensor inside the SCXI-1112?

Since I can't be sure how you have tried to set up the measurement, try following the steps mentioned in the SCXI Quick Start Guide just to be sure it's done correctly. If it's the b
uilt-in CJC sensor you're trying to take readings from, use the channel string mentioned in Knowledge Base 0Z63B4AQ.

I hope this helps!

-Russell
Applications Engineer
National Instruments
http://www.ni.com/support