The Design Of Highly Reusable DCS Simulator

In this project, some measures are taken to enhance the generalizability and reusability of DCS (Distributed Control System) simulator, thus improve efficiency of development work and reduce risks. These measures include:1. The system is designed as a modified layered system that consists of threelayers-the Operator GUI (Graphic User Interface) Layer, the Instrumentation &Control Layer and Process Model Layer, and one Overall Management and Communication module. The process model layer can be further divided into Process Flow Simulation, Unit Module and Properties/Algorithm sub layer. Inter-layer communications are handled and forwarded by the Overall Management and Communication module. This architectural design can greatly increase independency and reusability of high-level components.2. In Operator GUI Layer, through object oriented analysis and design, Static Bitmap, Static Vector-Graph Element, Dynamic Display Object, Operation Target Zone and Child Graph Object classes are created. Most DCS's GUI features can be implemented through configuration of data file rather than through modification of source code, because of complete data-code separation. We can produce user-defined display, control group display, detail display, and popup instrument faceplate using this technic. Extendibility is also ensured.3. A general purpose FBM (Functional Block Module) based Instrumentation & Control Layer is constructed and control strategies in most chemical process simulation projects can be built using the 10 kinds of FBMs produced in this project. Because of rational design of the FBM classes and the FBM container class, It is not difficult to add new FBM types which are defined by FF (Foundation Fieldbus) or other vendors.4.We also discuss the application of COM technology in simulation projects. By encapsulating high-level module in COM components, binary reusability and development language independence can be achieved. Furthermore, local/remotetransparency makes it easy to port our applications to network environment. In this project, we use COM technology to seal and call the Process Model Layer, which is written in VB.