Temperature transmitter is a kind of instrument that can convert the temperature variable to the output signal that can be transmitted, and is often used to measure and control temperature parameters in the industrial field. Under normal circumstances, the temperature transmitter with a sensor mainly contains two parts, one is the sensor and the other is the signal converter. Among them, the sensor is mainly a thermal resistor or thermocouple, and the signal converter group is composed of a conversion unit, a signal processing unit and a measurement unit.