The Design And Application Of Control System For Air-conditioned Cars

Air-conditioned car is an important aircraft ground support equipment, which is in charge of indoor air conditioning before the plane taking off and after the plane landed. When the airborne electronic equipment is power checking or debugging, it is also used to provide the appropriate temperature. Thus, in order to ensure the continuous working, it is needed to research and reform the control system of the air-conditioned car.This paper starts from the main functions of the air-conditioned car. Firstly, the structure and function of the system are introduced. Then the working principle of the cooling/heating system is descripted in detail. Finally, the control flow, the control task and the whole design scheme are proposed.The control system adopts upper-lower computer to acquisition and display the data, to monitor the system operation state in real time, and to diagnosis the alarm faults. The lower computer is based on Siemens S7-200 PLC, which includes DI module, actuator drive module, analogue collection module, upper and lower computer communication interface module and power circuit control module. The upper computer is based on MCGS, which can receive and store the real-time data and the feedback signal sent by the lower computer via the communication interface, and display the operation state and the real-time data via the human-computer interface. According to the real-time data and the feedback signal, the data processing module can distinguish the working state, and realize the alarming and the fault diagnosis function, which ensure the security and stability of the air-conditioned car.