For a long time in the electronics industry, temperature controllers are evolving rapidly. Because it can flexibly control the start and stop of air conditioning units in each region and indoor temperature, and can save building space and engineering cost, fan coil unit (FCU) plus fresh air air-conditioning system has been the most popular semi-centralized air-conditioning system in hotels, hotels and office buildings where rooms and business rooms are rented out as the main business. The temperature controller of room air conditioning is the key to control the cooling/heat supply of the terminal unit, the fan coil unit (FCU), and realize the temperature control of separate room and energy saving operation.

The general fan coil air conditioning temperature controller is basically an independent closed-loop temperature regulation system, which is mainly composed of temperature sensor, two-position controller, temperature setting mechanism, manual three-speed switch and hot and cold switching device. The control principle is that the air conditioning temperature controller according to the temperature sensor measured by the room temperature and the set value of the comparison result of the double control signal, control the hot and cold water circulation pipeline electric water valve (two-way valve or three-way valve) switch, that is, cut off and open the water circulation inside the pipe, adjust the air supply temperature (cooling capacity).

** generation of air conditioning thermostat is mainly electrical products, the temperature sensor of air conditioning thermostat adopts bimetal sheet or pneumatic temperature packet, through the "given temperature disc" to adjust the preload to set the temperature, fan three-speed switch and seasonal switch for the splash gear type mechanical switch. This kind of air conditioning thermostat products generally exist problems such as "too thick temperature setting index value", "too large time constant", "mechanical switch is easy to damage" and so on.

** generation of air conditioning temperature controller for electronic products, temperature sensor using thermistor or thermistor, some products of temperature setting and wind speed switch through the touch key and LCD screen to achieve human-computer interaction interface, hot and cold switch automatic completion, operation amplifier circuit and switching circuit to achieve double regulation. This kind of intelligent air conditioner temperature controller improves the human-computer interaction interface and solves the problems such as "too thick temperature setting index value", but there are still some problems such as "low control precision", "large time constant" and "complicated operation".

At present, domestic and foreign manufacturers are researching and developing the third generation of intelligent room temperature air conditioning temperature controller, some manufacturers actively respond to the national policy, the application of new control model and numerical control chip intelligent control. Now domestic manufacturers have produced intelligent room temperature air conditioning thermostat, and has been applied in practical projects. This production led to the development of the electronics industry.