Thermocouple is an indispensable temperature sensor for modern temperature measurement, and thermocouple is also a very simple and common temperature measurement instrument. The thermocouple error and product maintenance of thermocouple in the process of use are serious problems faced by the site.

Main factors affecting thermocouple error is as below:

1, the temperature sensor (thermocouple) insertion depth, response time, thermal radiation and thermal impedance, etc., pointed out the thermocouple wire heterogeneity, armored thermocouple shunt error, K type thermocouple selective oxidation, K state, service atmosphere, insulation resistance and thermocouple degradation in use should be noted.
2. Thermocouple selection: sometimes the actual needs of the site are not fully considered in the selection, but the selection is carried out with theoretical thinking, and the temperature adaptation range is too large or too small
3. Uncertain control of thermocouple material
4. The site environment of thermocouple was not fully considered
5. Skills of  thermocouple site operators