The Design And Research Of Virtual Monitoring System Based On OPC Technology

In high-speed systems such as high-speed rail and rockets, we usually take methods of controlling the weight of control systems or reduce detection equipments to improve the carrying capacity and ensure the speed and stability at the same time. In modern society, most of the systems take use of computers and use 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?s difficult to realize feedback control by the real-time value of the controlled objects. By the way, as the controlled objects become more and more complex and the control precision requests are higher and higher, it is more and more difficult to realize control algorithm simply by PLC programming. Even if the algorithm can be achieved, it is still difficult to monitor and display the control effect.In order to solve the problems described above, this article establishes the simulation platform based on the OPC technology by the integration of the Win CC, STEP7 and MATLAB. In the system, we establish the mathematical modeling of the controlled object according to its mechanism and the response characteristics. Then, we use the transfer function to realize the virtualization of the object in MATLAB, thereby it is possible to eliminate the need for detection device, transmission device and controlled device. In the system, we take Win CC as the core of the system for data transfer. By introducing Win CC, PLC is possible to communicate with MATLAB. What?s more, Win CC can be used to design the configuration and graphic in order to monitor the control effect. In the system, STEP7 takes the role of controller to design PID control algorithm and give control output. Thus, the trinity of the control platform in which WINCC works as a bridge is done.Besides, the article discusses the principle and implementation of fuzzy control algorithm in order to avoid the weaknesses of the simple PID controller. In this article, the Parameters self-tuning Fuzzy-PID Controller is introduced to the virtual control system we found above to change the PID parameters on-line based on the input of the controller and improve the response of the control system. In this virtual control system, the simulation of virtual object is realized by C scripting program of Win CC objects to save the detection device and controlled device. The control algorithm is written by MATLAB but not PLC as that it is difficult to realize complex control algorithm by PLC. Thus, we establish the Fuzzy-PID Controller &Win CC&Virtual Time-delay Object Platform based on OPC technology.In this article, we construct a simulation experiment platform based on OPC technology. This platform proves that the OPC technology is practical and effective in the industrial fields. What?s more, the platform can contribute to the development of new experiments in the labs and enhance the operability and observability of experiments. Besides, the simulation of virtual objects is achieved by MATLAB program and Win CC object’s C script. By this way, we can realize the algorithm testing and control process even that there are no detection and transmission equipments or it is unable to guarantee the stability of the equipments in some kinds of occasions. So, it?s helpful to save money in the process of projects development and test and to ensure the safety of the control process.