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Home > MEMS / sensing technology > How to troubleshoot temperature sensor

How to troubleshoot temperature sensor

Published time: 2020-08-24 16:00:48

The summer is getting hotter and hotter, and people simply cannot do without air conditioning. And now the air conditioner is more advanced. There is a temperature sensor inside. As long as you set the temperature, the air conditioner can control the shutdown and cooling by itself. Next, let’s take a look at the fault detection method of the air conditioner defrost temperature sensor. How to troubleshoot?

Fault detection method of air conditioner defrosting temperature sensor

Use a multimeter to detect the temperature sensor at the solder joint on the back of the computer board. Connect the black test lead of the multimeter to the ground, connect the red test lead to the solder joint of the temperature sensor, and select the 20V voltage range for the multimeter. Under normal circumstances, the voltage that the room temperature sensor sends to the microprocessor should be about 2V, if the sensor is damaged. The measured voltage value is 0V. The sensor expert network believes that the voltage value sent by the evaporator pipe temperature sensor to the microprocessor should be about 3V if the sensor is damaged. The measured value is 0V. When the measured sensor voltage value is 0V, it means that the external sensor is damaged and should be replaced.

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How to troubleshoot the temperature sensor

1. Room temperature sensor

It mainly detects the indoor temperature. When the indoor temperature reaches the set requirements, the operation of the internal and external units is controlled. The external unit stops during cooling, and the internal unit continues to run. When heating, the internal unit stops after blowing off the waste heat.

2. Indoor pipe temperature sensor

It mainly detects the coil temperature of the indoor evaporator, and plays the role of anti-cold wind, anti-overheating protection, and automatic temperature control during heating.

3. Outdoor defrost temperature sensor

It mainly detects the temperature of the outdoor condenser coil. When the temperature of the outdoor coil is lower than -6 degrees Celsius for 2 minutes, the internal unit turns to the defrosting state. When the resistance value of the outdoor coil sensor is too large, the indoor unit cannot work normally.

When detecting the failure of the defrost temperature sensor, you can use a multimeter, which is the simplest way to detect. After the fault is confirmed, the fault can be eliminated according to the above method.

What are the types of temperature sensors

Thermocouple sensor

A thermocouple is a loop formed by connecting two conductors with different components. When the temperature of the junction is different, a thermoelectromotive force will be generated in the loop. This phenomenon is called thermoelectric effect, and this electromotive force is called thermoelectromotive force. Among them, the end directly used to measure the temperature of the medium is called the measurement end, and the other end is called the compensation end; the compensation end is connected to the display instrument, and the display instrument will point out the thermoelectromotive force generated by the thermocouple. Thermocouples made of different materials are used in different temperature ranges, and their sensitivity is also different. The metal material used to make the thermocouple must have good ductility, so the thermocouple temperature measuring element has an extremely fast response speed and can measure the process of rapid temperature changes.

Non-contact temperature sensor

The sensitive element of the non-contact temperature sensor is not in contact with the measured object. This sensor is generally used to measure the surface temperature of moving objects, small targets, and objects with small heat capacity or rapid temperature changes. It can also be used to measure the temperature of the temperature field. distributed.

RTD temperature sensor

The thermal resistance temperature sensor is a kind of sensor that uses the principle that the resistance value of a conductor or a semiconductor changes with its temperature. For different conductors (semiconductors), the resistance value changes every time the temperature changes-degree, and the resistance value can be directly used as the output signal.

Contact temperature sensor

The detection element of the contact temperature sensor can make good contact with the measured object. It achieves a thermal equilibrium state through conduction or convection, so that the displayed value of the thermometer can directly indicate the temperature of the measured object.

The above is the introduction of temperature sensor knowledge, I hope it will be helpful to you.


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