CJC setting for SCC-TC02

[VI_Joe]

I'm using an SCC-TC02 thermocouple module in the SC-2345 SCC Carrier.  The DAQ card I'm using is the PCI-6221.  I understand that the SCC-TC02 has an onboard thermister for cold-junction compensation.  When setting the parameters for the DAQmx Create Channel.vi, I set the CJC Source to Built In.  By doing so, I assume that nothing else needs to done to compensate for cold-junction (no software conversion, etc.)  I have attached my vi.

Thanks in advance.

[RavensFan]

Correct.

Give it a try and reply back if you have any issues.

[VI_Joe]

I put my therocouple probe in an ice slurry and measured 0.98 degrees C.  I assume that this error was associated with the test set-up since I could watch the temperature gradually increase as the ice melted.  Also, only about half the length of the thermocouple probe was submerged in the slurry.  Any thoughts?

[RavensFan]

That sounds pretty good to me.  What is the problem?

[VI_Joe]

Didn't know how close to 0.0 I should expect my reading to be.  How much would the error be if there was no cold junction compensation in place?

[RavensFan · Accepted solution]

Without CJ compensation, the error would be based on what the cold junction temperature is vs. what you typed in as a constant.  So if you said room temperature was a constant 70degF, but it is in realtiy 75degF, then you'll have 5 deg F error in your reading.