Thermocouple Testing

An other temperature sensor in parallel and compare results.

Hi,

A simple way of testing a thermocouple to confirm if it's "working" assuming that it is in a thermowell and can be pulled out of it.

1) Disconnect the wires going to DCS or PLC located in the thermocouple's weather head

2) Find out what's the ambient temperature at that location

3) Put the two wires going to DCS or PLC together and see if the temperature reading on DCS or PLC matches the ambient temperature,if it does then the loop is working OK

4) Pull the thermocouple and reconnect the wires.Hold the thermocouple in the air for a few minutes if the reading on DCS or PLC matches the ambient temperature the the thermocouple is OK.

It's a lot easier to test the thermocouple with testing equipment please let us know what equipment you have access to and I will try to help you.

Thank you

Firstly, Using an ohm-meter check the resistance across both leads it should be 0 ohms.

Secondly, disconnect the TE from the transmitter or extension cable terminal assembly and use the appropriate test equipment (thermocouple calibrator or millivolt-meter) measure the actual temperature, if you have persons who are familiar with the process they will be able to tell if the readings are realistic. Note that this is not a conclusive test.

Or

Thirdly (this is the best way of testing), if the TE can be removed from service use a calibrated/certified temperature bath and temperature calibrator to verify the operation of the TE.

hello you can simply unwire the connection on the TC it self and measure the MV reading with multimeter and compare with this table http://srdata.nist.gov/its90/download/type_k.tab