Choose the thermocouple and thermal resistance temperature transmitter

Thermocouple is generally used in high temperature measurement, and thermal resistance are mainly low temperature measurement. Thermocouple

WRNR - 12 thermocouple is one of the most commonly used temperature detecting element in industry, the working principle of the thermocouple is based on baker ( seeback) Effect, that is, two different components of conductor ends connected into a circuit, such as two different connection end temperature, then to produce the physical phenomenon of thermal current in the circuit. Its advantage is:

1) measuring accuracy is high. Because of thermocouple direct contact with the object being measured, not affected by intermediate medium.

2. Wide measuring range. The commonly used thermocouple from - 50 ~ + 1600 ℃ can renew edge measurement, some special thermocouple minimum measurable to - 269℃（ Such as gold iron nickel chrome) , up to + 2800 ℃ ( Such as tungsten - Rhenium) 。

3. Simple structure, easy to use. Thermocouple is usually composed of two different kinds of metal wire, but is not limited by the size and the beginning of, outside has protective casing, which are very convenient.

the thermocouple cold end temperature compensation

as a result of the thermocouple materials are generally more expensive ( Especially when using precious metals) And temperature measuring points are far away the distance to the instrument, in order to save thermocouple materials, reduce cost, usually adopt the compensating conductor (of the cold junction of the thermocouple The free end) Reaches to the relatively stable control indoor temperature and connected to the meter terminals. It must be pointed out that the role of the thermocouple compensation wire only extend thermal electrode, make moves to the control room of the cold junction of the thermocouple meter terminal, it itself does not eliminate the cold end temperature change on the influence of temperature, no compensation. So, still need other correction method is used to compensate the cold end temperature t0 indicates influence on measuring temperature 0 ℃.

must pay attention to when using thermocouple compensating conductor model is suitable, the polarity can't wrong, compensation conductor should be connected to the thermocouple temperature should not exceed 100 ℃.

thermal resistor

WZP - Low temperature zone of the most commonly used in 230 thermal resistor is a kind of temperature detector. Its main characteristic is high accuracy, stable performance. Among them is platinum thermal resistance measurement accuracy is the highest, it is not only widely used in industrial temperature measurement, and is made into standard benchmark instrument.

thermal resistance temperature measurement principle and material

thermal resistance temperature measurement is based on the metal conductor resistance value increases with the increase of the temperature of the properties for temperature measurement. Heat resistance is mostly made of pure metal materials, the application at present most is platinum and copper, in addition, now have begun to use the materials such as nickel, manganese and rhodium manufacturing thermal resistance.

about temperature transmitter, you can look at the following introduction:

1, the purpose of the temperature transmitter

temperature transducer used for temperature measurement, this paper defines the temperature transmitter for the application of temperature sensor for temperature detection, through the conversion circuit of temperature sensor signal is converted into a standard current signal, standard voltage signal of the temperature measuring device.

2, the classification of temperature transmitter

from the signal output interface is divided into 4 ~ 20 ma, 0 ~ 10 ma, 0 to 20 ma, 0 ~ 5 v, 0 ~ 10 v, etc. , or digital/frequency interface and other interface;

from the structure and form into a wall-mounted installation, duct type, rod type;

on the distance from the temperature sensor and conversion circuit is divided into one-piece or split type;

and explosion-proof type products.

3, the basic principle of temperature transmitter

xiamen branch's son automation co. , LTD. , application of temperature sensor for temperature detection, the temperature sensor is usually heat resistance, thermal resistance, integrated temperature sensor, semiconductor temperature sensor, etc. , and then through the conversion circuit of temperature sensor signal is converted into a standard current signal or voltage signals.