Hello, my friends, I’m Big Brother, today let’s talk about the wiring of the temperature controller. There are many models of temperature controllers, and the output methods are slightly different, but the wiring principle is the same. As long as we understand the working principle, we can directly wire any temperature controller.
The working principle of the temperature controller: The main circuit of the power supply is directly connected to the heating device through the main contact of the AC contactor. The temperature sensor senses that the temperature at this time is lower than the set value, and the total low-conductivity contactor coil is energized. The heating device starts to work. When the temperature reaches the set value, the total low disconnection turns to the total high conduction, the contactor coil loses power and the contact resets, and the heating stop temperature gradually decreases. When the temperature falls below the set value, it changes again For total low conduction, heating starts to work in this cycle. There is a temperature "hysteresis" in the middle, and most temperature controllers can set the temperature "hysteresis" range. The parameters and setting methods of temperature controllers of different brands are slightly different. For the wiring method, please refer to the manual and the wiring diagram on the temperature controller.
There are three main sets of contacts on the temperature controller: power contacts, a set of high and total low relay output contacts, and the contacts of the temperature sensor. As shown in the above figure, the neutral phase is the live wire, which is always the common terminal, and the total high is normally closed and the low is normally open. The relay output of this group is passive, and an external power supply is required for use. 123 is connected to a temperature sensor. Two-wire thermocouples are common. Generally, the red wire is positive and the blue wire is negative. Do not make mistakes about the positive and negative. There are also three-wire thermal resistors. Two wires are of the same color, and the wiring is in no order. The third wire is connected to the positive terminal, and the two wires are connected to the input negative and external supply negative. (Two wires of the same color are used to eliminate the influence of wire resistance on the measured value)
The above is a physical reference diagram, this is a relatively common wiring method. Press the start button, the self-locking electric heating tube of the contactor will start heating. When it is heated to the set temperature, the total is low and the contactor loses power and the heating tube stops heating.
Some temperature controllers may have more contacts. Let's take the above picture as an example. 13 and 14 are connected to the power supply, and 12 is grounded (some internally suspended can not be connected). AL marked can be connected to the alarm device, 123 connected to the temperature sensor, 6 and 7 correspond to SSR, a set of DC signal output, we can use to control the solid state relay, pay attention to the positive and negative when wiring.