The integrated temperature transmitter generally consists of a temperature measuring probe (thermocouple or thermistor sensor) and a two-wire solid-state electronic unit. The temperature probe is directly installed in the junction box in the form of a solid module, forming an integrated transmitter. Integrated temperature transmitters are generally divided into two types: thermistor and thermocouple.
　　
The thermal resistance temperature transmitter is composed of a reference unit, R/V conversion unit, linear circuit, reverse protection, current limiting protection, V/I conversion unit, etc. After the thermal resistance signal is converted and amplified, the non-linear relationship between temperature and resistance is compensated by a linear circuit. After the V/I conversion circuit, a constant current signal of 4-20mA is output, which is linearly related to the measured temperature.
　　
Thermocouple temperature transmitters generally consist of circuit units such as a reference source, cold junction compensation, amplification unit, linearization processing, V/I conversion, decoupling processing, reverse connection protection, and current limiting protection. It amplifies the thermoelectric potential generated by the thermocouple through cold junction compensation, then eliminates the nonlinear error between thermoelectric potential and temperature through a linear circuit, and finally amplifies and converts it into a 4-20mA current output signal. To prevent accidents caused by temperature control failure due to thermocouple wire breakage during thermocouple measurement, the transmitter is also equipped with a power-off protection circuit. When the thermocouple breaks or is poorly connected, the transmitter will output the maximum value (28mA) to cut off the power supply of the instrument.
　　
The integrated temperature transmitter has the advantages of simple structure, wire saving, large output signal, strong anti-interference ability, good linearity, simple display instrument, solid module seismic and moisture-proof, reverse connection protection and current limiting protection, and reliable operation.
　　
The output of the integrated temperature transmitter is a unified 4-20mA signal; Can be used in conjunction with microcomputer systems or other conventional instruments. It can also be made into explosion-proof or fireproof measuring instruments according to user requirements.