Design And Implementation Of OPC DA Server In Semi-physical Simulation System

With the development of simulation technology, simulation system becomes more and more complex. However, semi-physical simulation system is getting widely used because of the feature of simple architecture and real-time. Semi-physical simulation system includes hardware part and generates real-time output with dynamic input. Hardware parts must receive necessary information from model part or simulation software, and send feedback information to the simulation unit. So, how to implement the general interface between hardware part and simulation unit is a main issue.OPC, based on Windows platform, is a kind of international standard used for accessing data of processing control. This thesis discussed the design and implementation of OPC DA Server in semi-physical simulation system. First, this thesis analyzes OPC data access specification deeply, researches the most important interface and object model which are defined in data access specification, and thereby gets a set of basic function. Second, this thesis researches COM, the technology basis of OPC, and provides implementation method of COM. According to OPC data access specification, this thesis indicates that implementation an OPC server with creating out-of-proc component. Third, this thesis emphasizes on how to design an OPC DA Server model in semi-physical simulation system, and designes the main three class object, including server object, group object and item object. And their attributes and methods are also designed. Meanwhile, this thesis designes other issues which include multi-thread design, subscription, sync/async reading and writing. Finally, this thesis provided a testing for OPC server. The result indicates that this server and OPC DA specification match pretty well.