Research And Design Of Virtual Model Library For Virtual DCS Based On IEC61131-1Standard

According to the characteristics of development and direction of DCS, our group working on a virtual simulation system based on IEC61131-3standard. The virtual DCS consists of engineer station, virtual DPU, virtual function library, virtual model library and HMI. This paper studies the design of virtual model library in virtual DCS, virtual DPU get service from virtual model library that act as an independent server.The virtual model library completes the controlled object in real industrial control systems, mirroring the performance and features of the real object. Firstly, I analyze the development and current status of DCS. I also analyze the characteristics of virtual DCS. Then, I introduce COM component technology and IEC61131-3standard. To realize of the controlled object model, I analyze the question using object-oriented thinking. And then,I complete the discrete processing of the transfer function using backward difference method, bilinear transformation method etc. I establish continuous model, nonlinear models, discrete model and typical models. Each model is developed into COM component through ATL technology. COM components encapsulated the model function, and the external module gets the model by calling component interface. I integrate all models by containment of component and packaged in EXE files as a server. The virtual model library is established according to IEC61131-3standard. Model library initialization information could be got from the engineer station configuration. Virtual DPU write the initialization of model library in to an INI file. Model components will be configured by reading the information in the INI file.Virtual model library communicate with virtual DPU in the form of client/server. The model library’s interface data is VARIANT, so that it is consistent with the virtual DPU. Virtual DPU obtain the Model code by parsing the configuration file. And call the library component’s interface, so that the model can be initialized. Meanwhile, this paper also test and monitor the model to ensure the correctness and effectiveness. At last, Virtual DCS could be running normally.