In the modern industrial field, there are many varieties of temperature sensor elements and many types of signal output. In order to facilitate automatic detection, unified regulations are made for the signal output of various temperature sensors, that is, a unified 4-20mA signal. In order to make the output of various temperature sensors unified into a signal of 4~20MA, a temperature transmitter is used. The temperature transmitter is used to make the various resistance and potential signals input into a unified 4~20MA current signal, which is the origin of the temperature transmitter. After the temperature transmitter completes the acquisition of the measurement signal, it is converted into a unified 4~20MA current signal output. It also acts as an isolation.
According to the working principle (mainly the difference of the thermal element), it can be divided into: thermocouple, thermal resistance (metal) and semiconductor thermistor.
The integrated temperature transmitter organically integrates the temperature sensing element (thermal resistance or thermocouple) with the signal conversion and amplification unit, and is used to measure liquid, steam and other gases in the range of -200-1600 °C in various processes The temperature of the medium or solid surface. The temperature sensor is affected by the temperature of the measuring medium to produce a resistance or potential effect, and a differential voltage signal is generated after conversion. This signal is amplified by the amplifier, and then converted by voltage and current, and the current signal of 4-20mA corresponding to the range is output. It is usually used in conjunction with display instruments, recording instruments and various control systems.