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Large temperature offset with JLD612DC and thermocouples

Posted: Fri Dec 02, 2011 7:36 am
by k-steddom@tamu.edu
I recently purchased a JLD612 and I am having trouble with the temperature readings. When I attach a type t thermocouple I get a PV reading of -14C in ice water, 3C at room temperature of 19C (measured with a thermometer), and 20 when placed in a 37C incubator. When I use a type k thermocouple I get -12C in ice water, 6C at room temperature of 19C, and 17C in the 37C incubator. I have checked the thermocouples on my data logger and they work fine (+/- 2C). I have double checked the intY setting (t for type t and backwards 4 for type k) and even tried reversing the leads of the thermocouples. With the type t thermocouple I can sort of calibrate the error out with PSb even though the offsets range for 14C to 17C but the coefficients for the type k range from 12C to 20C. I am not sure what else to check at this point. I have read in one of the other posts that offsets shouldn't be that large, though in that case the problem was traced back to a defective thermocouple.

Re: Large temperature offset with JLD612DC and thermocouples

Posted: Tue Dec 13, 2011 11:37 am
by richiem
Seems like it could only be one of two problems:
1) the thermocouples are hooked up to the wrong terminals
2) the JLD612 is bad

Re: Large temperature offset with JLD612DC and thermocouples

Posted: Tue Dec 13, 2011 6:38 pm
by k-steddom@tamu.edu
My first thought was the thermocouple leads were reversed so I swapped them and the sensed temperature went up when it should have gone down.