Temperature Readings Problems

[Willy7]

I am using a SCXI-1000 with three modules attached, 1200, 1163 and 1120. The first 2 are not being used currently (except the fact that the 1200 controls
the chassis). The 1120 is being used to acquire temperatures from thermocouples inside a refrigerator. When the air conditioning is turned OFF in the room
of the tests (everything is in the same room, from the refrigerator to the computer), the ambient temperature, of course, raises. There's a thermocouple
reading the ambient temperature, and then it indicates a slight increase of temperature (less than 1?C), and the temperatures read inside the refrigerator go down around 2?C. I then stopped the acquisition and started it again immediately, and all the temperatures raised (including t
he ambient temperature). The temperatures inside the refrigerator returned to the previous levels
(before the air conditioning went off). I am using virtual channels, and the acquisition is set up at programa start with AI Config and AI Start. By this way
the CJC should be updated every reading, right? What's the reason for that?

Thanks in advance,

Guilherme

[aderogba]

When I had a similar problem it was because my SCXI mainframe (with the modules) is located too far away from the Thermocouples. I realized that I couldn't use Built-in for CJC source in MAX set-up. I'll suggest you check your terminal block, thermocouple type, if variation is consistent with all channel/thermocouple, and "CJC source" in MAX. Also check the system response with a fluid of know temperature.