Development Of Control Configuration And Simulation Software Based On New DCS

New DCS (Distributed Control System) mentioned in this project is a new control system based on industrial Ethernet and Fieldbus, which is a major scientific research project from Department of Science and Technology in Shandong Province. It has many advantages in both hardware and software. Considering specific functions and technical realization, configuration software can be divided into several modules based on modularization method. Control configuration software with the function of system simulation is an important part among these modules. It can realize configuration, simulation and real-time run monitoring of control strategies which run in new DCS's field control station.Traditional control configuration software can configurate control strategies, but can't simulate these strategies. New DCS's control configuration and its simulation software introduced in this project makes some improvements. It can be used to configurate control strategies by engineers, and it also can provide operators with simulation training. In order to simulate control strategies, configuration mode must be identical with field operating mode. As a result, fieldwork and debugging can be realized by means of simulation software. Investments can be reduced, and some risks of production can be avoided.To meet requirements of software development, Object-Oriented Programming (OOP) is used as program design method. On the platform of Windows 2000, new DCS's control configuration and its simulation software is realized in Microsoft Visual C++ 6.0.Background and significance of this project are introduced in this paper, and architecture of new DCS based on industrial Ethernet and Fieldbus is also introduced. Then, modularization, system structure and distributed architecture are analyzed in detail. Spiral Model (SM) is adopted to be the model of software development.Considering configuration software requirements, this system adoptes Function Block Diagram which is one of the five IEC61131-3 standard languages to achieve configuration environment design and projects management, then use MDI architecture of Visual C++ to implement visual configuration environment. The definitions of several relational classes are abstracted according to Object-Oriented Programming and modular design philosophy. The paper gives a very detailed introduction to the important topics, such as, the usage of factory mode, sorting algorithm function modules by using directed graph topology, improved Johnson algorithm and DAG sorting algorithm. The support allowing users to do secondary development by using the technology of Dynamic Link Library (DLL) is explained as well.Simulation implementation method is explained in detail in this paper. The control configuration software uses the unified real-time data communication interfaces to interact with the whole configuration software. The system uses multi-threaded design method to realize the simulation algorithm scheduling. The principles to realize the functional modules used in mathematical model building is specified too. The real-run design and communication mechanism with the main control card is also described. And, control strategies online modification method is creatively proposed in this paper.A simulation test is taken to compare to Matlab simulation results. The results show that the simulation in this paper is accurate. And, it proves that the design scheme and implementation method are feasible. It also achieved good results in the practical application of Water Tank Level Control System. So, the system has a good utility value. Finally, it gives the summary and prospects.