A Control Based on PLC of New Air and Return Air Valves in Air Conditioning Unit

In this paper, we mainly discussed the new air valve and return air valve of the air conditioning unit. We input the temperature and humidity information, which was tested in new air channel and return air channel by the sensors, into the Programmable Logical Controller (PLC) through the analog input module. Through the enthalpy calculations, we can control the openness of the new air valve and return air valve in order to achieve the control requirements.