Classification and Development of Explosion-proof Temperature Transmitter

Explosion-proof temperature transmitter indirectly measures temperature by measuring some parameters of the object with the change of temperature. A good explosion-proof temperature transmitter should have many conditions, such as wide temperature range, high precision, fast response, good reliability, low price and so on. There are two types of explosion-proof temperature transmitters: contact type and non-contact type. Contact explosion-proof temperature transmitter has the characteristics of low price, slow response speed and simple structure. Non-contact explosion-proof temperature transmitter has fast response speed. It can also be used to measure high temperature and corrosive occasions.

Explosion-proof temperature transmitters are classified according to principle

1. Expansion thermometer

Expansion thermometer is made on the principle of conducive to thermal expansion and contraction of objects. It can measure objects of about - 200 - 500 degrees Celsius. This is the type of thermometer commonly used.

2. Resistance explosion-proof temperature transmitter

The resistive explosion-proof temperature transmitter uses conductors or semiconductors in the temperature field. With the change of temperature, the principle that the resistance will change is made. We know that platinum resistance and copper thermal resistance belong to the conductor category. Semiconductor category mainly includes thermistor. Its measuring range can reach 1000 degrees Celsius.

3. Thermocouple explosion-proof temperature transmitter

The working principle of thermocouple is based on thermoelectric benefit. Two different conductors are composed of closed circuit. Because of the different temperature of two points, thermoelectric EMF will be formed. Thermoelectric EMF is only related to the material and temperature of conductor. Thermocouple explosion-proof temperature transmitter can measure a wide range of - 300 - 2800 degrees Celsius.

4. Integrated explosion-proof temperature transmitter

The integrated explosion-proof temperature transmitter is an explosion-proof temperature transmitter which integrates temperature sensor, amplifier circuit and compensation circuit on a very small chip. It is the fastest-growing explosion-proof temperature transmitter. Its advantages lie in good linearity, fast response and standardized output, but its disadvantages lie in the narrow measurement range, generally at - 50 - 150 degrees Celsius, which is mainly related to the use conditions of components.

5. Development Stage of explosion-proof temperature transmitter

(1) Traditional discrete explosion-proof temperature transmitter (including sensitive elements);
(2) Analog integrated explosion-proof temperature transmitter/controller;
(3) Intelligent explosion-proof temperature transmitter.

After entering the 21st century, intelligent explosion-proof temperature transmitter is developing rapidly in the direction of high-tech, such as high precision, multi-function, bus standardization, high reliability and safety, development of virtual sensors and network sensors, and development of single-chip temperature measurement system. At present, explosion-proof temperature transmitter as slave can communicate with host through special bus interface.
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