I have a problem with a thermocouple in my experiment that I thought I should ask here.
I have a reactor that has a heating rod in the center of it. There are some thermocouples in my reactor and all of them are attached to a multiplexer board that I made. Also there is a K type thermocouple placed in that rod to measure its temperature. Every time I attach the central heater's thermocouple to the multiplexer board or directly to the Labjack U6, I cannot read it on computer and it messes up other thermocouples as well. But I tried reading it on a handheld Omega Thermocouple reader and it worked fine. I can read other thermocouples on my program which means the multiplexer board and Labjack U6 are working fine as well.
Can any body tell me what could be wrong or how I can troubleshoot this problem?
Thanks in advance.