For a long time, in the electronics industry, temperature controllers are developing rapidly. Because it can flexibly control the start-stop and indoor temperature of air-conditioning units in each area, and can save building space and project cost, the fan-coil unit (FCU) plus fresh air air air conditioning system has always been a semi-centralized air conditioning system for hotels, restaurants and office buildings, which mainly rents rooms and business houses. The temperature controller of room air conditioner is the key to control the cooling/heating provided by the terminal device, the fan-coil unit (FCU), and to realize the temperature control in different rooms and energy-saving operation.

The thermostat of ordinary fan-coil air conditioner is basically an independent closed-loop temperature regulation system, which is mainly composed of a temperature sensor, a two-position controller, a temperature setting mechanism, a manual three-speed switch and a hot and cold switching device. The control principle is that the air conditioner thermostat generates a two-position control signal according to the comparison result between the room temperature measured by the temperature sensor and the set value to control the switch of the electric water valve (two-way valve or three-way valve) of the cold and hot water circulation pipeline, that is, the air supply temperature (cooling supply) is adjusted by cutting off and opening the water circulation in the coil.

* * The air conditioner thermostat is mainly an electric product. The temperature sensor of the air conditioner thermostat adopts a bimetal or a pneumatic temperature bag, and the temperature is set by adjusting the pre-tightening force through a "given temperature dial". The three-speed switch of the fan and the seasonal switch are mechanical switches. This kind of air conditioner thermostat products generally have some problems, such as "the temperature setting division value is too thick", "the time constant is too large" and "the mechanical switch is easy to be damaged".

* * The air conditioner thermostat is an electronic product, and the temperature sensor adopts thermistor or thermal resistor. The temperature setting and wind speed switch of some products realize man-machine interaction interface through touch keys and LCD screen, and the hot-cold switch is automatically completed, and the operational amplifier circuit and switch circuit realize two-position adjustment. This kind of intelligent air conditioner thermostat products improve the man-machine interface and solve the problems such as "the temperature setting division value is too coarse", but there are still some problems such as "low control accuracy", "large time constant" and "complicated operation".

At present, domestic and foreign manufacturers are researching and developing the third generation intelligent temperature controller for room temperature air conditioning, and several manufacturers actively respond to the national policies and apply new control models and numerical control chips to realize intelligent control. At present, domestic manufacturers have produced intelligent temperature controllers for room temperature air conditioners, which have been applied in practical projects. This production drives the development of the electronics industry.