Research And Development Of OPC DA Server And Virtual DCS Model Server

Because the real DCS (Distributed Control System, Distributed Control System) is insufficient in terms of the design and debugging, danger drills, detection, diagnosis, etc, the research group work on designing a set of distributed virtual DCS system based on COM component technology. Virtual DCS system consists of the engineer station, virtual DPU, virtual model library and HMI. This paper studies and designs virtual model library and OPC DA server in virtual DCS system, and implements the various parts of the entire virtual DCS distributed-call between each other.Virtual model library provides virtual controlled object model of real industrial control systems to virtual DPU client as a standalone server. OPC DA server implements seamless data connectivity between virtual DPU with HMI platform.This paper is based on the background of virtual DCS. Firstly, analysis and comparison three kinds of distributed technology,.net Remoting, Socket and DCOM. Then, aim at the applications of OPC technology in virtual DCS standardized communications, launch a more in-depth study. To the realization of the controlled object model, use the object-oriented thinking to analyze the model and discrete its transfer function. Last, we built four kinds of models:continuous model, non-linear model, discrete model and typical model. Each type of models are developed into COM components by using ATL tools. COM components encapsulate the model functions, and the external invokes models by component interface. All models are integrated by containment of component and packaged in EXE files as a server. OPC DA Server is developed based on OPC data access custom interface specification version 3.0 by using the Visual Studio 2010 development tools and applying COM technology and C++ language. OPC server, through the interface provided by the driver of specific data sources (virtual DPU), read and write data. The OPC server realizes real-time data updates of its virtual DPU data store by using the message mechanism. And achieve in OPC server of virtual DPU data inside. Use ForceControl configuration software to develop HMI of virtual DCS which connect OPC server via an internal OPC client of configuration software. And ultimately achieve data access to virtual DPU and seamless connection, and realize information sharing and virtual DCS standardization communications.Virtual model library and OPC DA server realize the distributed communication with virtual DPU by using DCOM technology. It’s verified that whatever the validity and correctness of the object model or the real time of data achieve good effect.