Measurement method of thermocouple time constant based on fast laser constant temperature zone

In order to solve the step temperature problem during test of thermocouple time constant, fuzzy control algorithm was used to feedback control the laser output power, a new parameter adaptive fuzzy proportion-integration-differentiation control algorithm was implemented and the hardware of closed-loop control system was analyzed. The experimental results show that, the time constant data of K-type thermocouple is 421.1ms. The algorithm can effectively shorten the balance time and enhance the anti-interference ability of the temperature control system. This research is helpful for the calibration research of thermocouples, and has certain engineering reference and application value.