| With the increasing scale of the industrial production, the Distributed Control System (DCS) has been applied more and more widely in the control field. The Configuration Software of the DCS is a kind of application software that runs on the engineers station and operators station, and is used for process monitoring and control. It is the centralized operation and management part of the DCS system. The DCS system, attached with mature Configuration Software, is important development trend in the industrial control, so this research has important theoretical significance and practical value.Firstly, the new DCS system structure based on CAN bus is introduced. Secondly, according to the requirement and features of the DCS system , this paper analyzes the requirement and the structure of the Configuration Software to draw a conclusion that the development system and the runtime system compose the software system. The Configuration Software employs the modular design method and can be divided into several functions. The framework and database system are the key study objects. Finally, based on the Windows platform and Visual C++ 6.0, this paper analyzes the software framework and realizes several basic functions such as the database subsystem, the visualization environment and the I/O driver program which communicate the Configuration Software and field control station, by adopting object-oriented programming.Framework design is the first step of the development process. The framework of the Configuration Software is fully elaborated by studying the architecture, the functions and the coordination mechanism of the software. Finally, the visualization environment of the development system and the runtime system, which are the integration of functions, are designed separately. The data management mechanism based on files and database accomplishes the data information transmission between the configuration system and the runtime system. The configuration flowchart under the development system and the communication mechanism between the functions of the runtime system are discussed.Database system is the core of the system. After analyzing the collectivity demand and the structure of the database system, this paper divides the database system into two parts: the configuration database system and the real-time running database system. The data structure of the configuration database system, which is realized to store system configuration information, is designed in detail. It is Emphasizing to analyze the design and implementation of the real-time running database system, which is based on SQL Server 2000. The object-oriented method is used to design the data modeling of the real-time data. The real-time running database is designed according to the main-memory database technologies, and both the AVL tree and the cocurrent accessing based on lock mechanism are used to improve the real-time performance of it to meet the demands of the DCS system. The real-time data storage structure in main memory is discussed. The mapping between relational database and the real- time running database is perfectly realized by using the object-oriented real-time data model, and, consequently, the storage and query of the historical data can be processed with SQL Server 2000. The data exchange interface, based on the Component Object Model (COM), between the database system and the other system functions is proposed and realized.The I/O driver program is designed with Dynamic Link Library (DLL) and multithreading technique, thus facilitating the scheduling and optimizing the resource allocation. It establishes the communication between the Configuration Software and field control station through Industrial Ethernet to realize the distributed real-time data acquisition. The I/O driver program realizes TCP/IP network communication by windows Socket. This paper describes the system frame and working process of the driver and its scheduling under the real-time running database system. |
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