I am trying to measure temperature using a thermistor probe, http://www.omega.com/ppt/pptsc.asp?ref=THX-400-NPT&Nav=temd14 , and the cfp-tc-120. To do this, I am using the Temperature Measurement.vi example. When I connected the probe to pins 1 and 2, i got a constant reading of -56 which made no sense to me. I decided to connect the probe to pins 36 and 37 and changed the fieldpoint IO point to CJ temperature. I still got a reading that I did not understand, but at least I could see the reading changing when i placed heat to the probe. I am new to Labview so I'm not sure if I am going about this the right way or how to get a correct temperature measuremment. Any help would be greatly appreciated! Thanks!
thanks for the suggestion Matt. I ordered the part suggested but I am still having some problems. I am still get a reading of -56 although when i put my hand on the thermocouple, you can see the reading increasing. Should I just put it in some ice water and scale it to that? thanks for your help! -Tania
The TC-120 is expecting a cold junction temperature reference so that it can properly calculate the delta T reported by the TC sensor. There is a cold junction sensor built into the CB-3 connector block. I expect you could duplicate the function of the CB-3 if you can find out what sensor is built into the CB-3 and use one of those in your setup. Probably easier to just get a CB-3, however.
Without a cold junction reference you won't get an accurate temperature measurement.