Distributed Control System For Cold Storage's Refrigeration

With the improve of living standard, the application of cold storage's refrigeration systems increases, and the control demand changes high. In this paper distributed control system (DCS) of the cold storage's refrigeration system is presented in order to improve dairy's working conditions.DCS with few sets, several sets are even several hundred computers about the application control in the process, All information are controlled by the upper computer with the communication network, this makes the best control. With the CRT equipment, the data communication line, the keyboard, the printer etc. The high concentration operation and display and the alert of information can be gotten. The whole device succeeded the advantages of the normal imitative instrument and the computer central control, it overcomes the risk of highly concentrate of the single computer control system and the weakness of the simple function of the normal imitative instrument.The dairy products company's condition is analyzed, then aimed at the distribute of the cold storage plant and refrigeration site and the requests of the equipments, the solution of the hardware electric circuit is obtained. In the each cold storage plant and the refrigeration station, PLC is used as the automatic control core ( the spot work station) ,a computer is used as the system control workstation(the upper workstation of the system).it is linked by the rs-422 total line, and formed a network, it can proceeds the whole system by the mode ,that the host computer whirligig query locale workstation.With the request of automatic control of the temperature of the cold storage plant, introducing the fuzzy theories, the system has two temperatures inputs and two outputs, that is the system discharge slide valve opening and state of the blower. The fuzzy control system was designed with two inputs and two outputs, and it is used to proceeds to system the intelligence control.The system fuzzy control form can be obtained by the fuzzy system input, and fuzzy calculate with the given system control form.In actual processing of the application, the output can be obtained through the form searching, when the control system get the temperature of the cold storage plant, then the automatic control of the temperature of the cold storage plant is put into relativity.Finally, the software of the control system of the station is designed, the software of the locale workstation is also designed, and the system's network communication protocol is setup.This system has many characteristics, such as concentrates to display the operation the management, and control opposite asunder, install vivid, convenience, expand the strong etc.At the same time, a fuzzy control was introduced to realize the automatically regulating the temperature of the cold storage plant, and the reasonable allotment of the motive energy, it consumedly increased the system's stability and efficiency.