Integrated temperature transmitterIt is generally composed of a temperature sensor probe and a two-wire solid-state electronic unit. It adopts a solid-state module form to directly install the temperature sensor probe in the junction box, thus forming an integrated transmitter. Integrated temperature transmitter is a combination of temperature sensor and transmitter, which converts temperature signals within the range of -200~+1600 ℃ into a two-wire 4-20mADC electrical signal in a very simple way and transmits it to display instruments, regulators, recorders, DCS, etc., to achieve temperature measurement and control. Integrated temperature transmitters can usually be divided into two types: thermistor and thermocouple.
　　
Thermal resistance type 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 to 20mA is output, which is linearly related to the measured temperature. Some temperature transmitters have added display units, while others also have fieldbus functionality.
　　
Thermocouple type temperature transmitters typically 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 to 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 is broken or poorly connected, the transmitter will output the maximum value to cut off the power supply of the instrument.
　　
　　Integrated temperature transmitterIt 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. Its application range is very wide, it can form an integrated on-site installation structure with thermocouples and thermistors, and can also be installed as a functional module in detection equipment and instrument panels for use.