fieldpoint config and functions

[M_B1]

Hi Kunal227,

The cFP-TC-120 and the FP-TC-120 are the same module, but just made for two different platforms.  So the user manual and the information pertains to both TC-120's.  As for measuring voltage, the cold-junction compensation will not be enabled when you measure just voltage, so you will not see it fluctuate.  I hope this helps out.

[uvenchong]

Michael,

If I make my own thermocouples from a roll of T-Type thermocouple wire that I bought from Omega, and I measure just voltage from the [c]fp-tc-120, should these voltages line up or at least come close to the voltage versus temperature chart published by NIST?

The reason I ask is because they don't come close at all. In fact, they are shifted and there is a bias error equivalent to the internal CJC temperature. For example, at 50C, I get a voltage reading of 1.19mV. When I look at the NIST publication, 1.19mV should have corresponded to approximately 30C. The difference of about 20C was the internal CJC temperature. Do you know what I am doing wrong?

Thanks,
Uven

[CharlieM]

Hi Michael,

First, the readings you have seen with you TC 120 are not entirely unexpected. Not correcting for errors associated with CJC issues can cause large measurement inaccuracies. Second, I wonder why you are choosing to do temperature measurements with raw voltage readings and no CJC? To perform such measurements accurately, I would recommend calibrating your own offset with a type of ice bath calibration procedure. Third, in going forward with such measurements, I would go through the below, basic verification steps:

1.      Use a battery (or other voltage source) to verify the cFP read data

2.      With the thermocouple attached, use an accurate Voltmeter to check the reading across the terminals of the TC 120

3.      Try multiple thermocouples

4.      Use the TC 120 to make thermocouple readings with CJC

[RavensFan]

Same question was started in a new thread here.