Thermocouple sensor wiring method

At present, the thermocouple is converting temperature changes into changes in resistance values. Usually, the resistance signal is transferred to the computer control device or its-secondary instrument. The industrial thermocouple temperature sensor is installed at the production site, which is a distance from the control room Qi Peng. Therefore, the lead of the thermocouple will have a greater impact on the measurement results.

There are three main ways to lead the leadership of the thermocouple sensor

Second -line system
At the two ends of the thermal resistance, the second -line system is to learn to build the electricity: this kind of leading method is simple, but because the connection wire must have the leading wire resistance R, the R size is related to the factors and length of the wire material, so this lead method only method is only the method of leading the wire. Therefore Suitable for low measurement accuracy.

Three -line system
Connect a lead on one end of the root of the thermocouple temperature sensor, and the two -terminal method of connecting two leads is called a three -line system. This method is usually used with the bridge. The most commonly used in program control.

Four -line system
The way to connect the two wires at both ends of the thermal resistance root become a four -line system. Two of them provide a constant current for the thermal resistance, turn the R to a voltage signal U, and then draw U to the second instrument through the other two leads. It can be seen that this leading method can completely eliminate the resistance effect of the lead, which is mainly used for high -precision temperature detection.