The Application Of Three In One Control Platform Based On OPC In Time-varing And Time-delay System

The large scale of industrial production makes the industrial process more complicated, and the controlled object generally has time-dependent nature, time lag, non-linear and so on, which also put forward higher requirements for the design of industrial process control system. For most of the control system, The controlled object usually can not be fully equipped with testing analog devices, but in modern society, most of the systems take use of computers and the digital variables that fed back by detection equipments to form effective closed loop control systems. The deletion of the detection devices results that it is difficult to realize feedback control by the real-time value of the control objects. The normal PID control system has the character of easy to achieve and its simple structure. But it is difficult to meet the control requirements of the complex system. The fuzzy control system has the character of simple structure, strong robustness, no need to confirm the precise mathematic model of the controlled object and so on. The quantifying factor of the fuzzy controller confirmed by the physical universal and fuzzy universal of the input variable, and the physical universal of the input variable continually changes. The fixed quantifying factor can not meet the control precision, so introducing the variable universal self-adaptive fuzzy controller. The Smith predictive compensation controller has a very good control effect for time-delay system. This article combines the variable universal fuzzy controller based on Mamdani model, the PID controller and the Smith predictive compensation controller together to get the variable universal fuzzy smith predictive compensation controller.The control algorithm of the variable universal fuzzy smith predictive compensation controller is very complex, and it is very difficult to design the control algorithm only by PLC programming, what more, it is difficult to monitor the system. This controller is built by the three-in-one control platform composed by the PLC, WINCC and MATLAB. PLC is not good at complicated arithmetic, but MATLAB does, so MATLAB makes up this disadvantage of PLC. The variable universal fuzzy controller is designed by MATLAB and PLC300, and the WINCC does the screen monitor about the real-time status of the control system. The communication and integration between MATLAB and WINCC realized based on OPC protocol, which solves the difficulty of realizing the real-time data exchange between different control system. In the system WINCC is to be as the OPC server, and MATLAB is to be as the OPC client. WINCC and PLC300 do real-time data exchange through MPI interface, and then the three-in-one control platform composed of PLC, WINCC and MATLAB is built.