Hi all,
Currently I am currently trying to take some measurements in an aqueous environment using a J-Type thermocouple. I run into some problems with the measurement as the thermocouple works fine but as soon as the heat source (radio frequency probe) is introduced, the values either revert to 0 or a very large negative number. I expected these high frequency values to be blocked by the integrated low pass filter of the NI-9213 receiver that I am using but apparently I was wrong. The radio frequency probe functions at roughly 400-500kHz. Anyone have any kind of input as to what should be done in order to eliminate this noise? I have thought of implementing an extra low pass filter but that is impossible to do once the data is input into LabVIEW given that the temperatures are just output as an array and cannot be filtered. Another thought was building a separate low pass circuit for all of the inputs before it passes into the receiver.
Any ideas and help would be greatly appreciated.