The Development And Design Of OPC Server

OPC foundation bring forward a new Process-control standard-OPC (OLE for Process Control) standard, under the condition ofbeing short of an identical standard in the Process-control field. The thesis developes a DLL with all the interface of OPC Data Access .A server which accords with OPC srandard will be developed rapidly by making use of the DLL.Firstly the thesis briefly states the new Process-control standard which called OPC standard and introduces its three specification and its application. At the same time , the thesis refer some advantages which OPC standard incurs in the Process-control field . Secondly, it detailedly recommends the technical principle of OLE/COM which is the basic technique of OPC standard and emphatically discusses some characters of COM technique, such as language irrelativity, reusability and so on , and the communication of COM technique, included connectable object mechanism, the UDT (uniform data transfer) mechanism and DCOM technique. Then, the development of DLL is emphatically stated in the thesis. The DLL encapsulates all the interface of OPC Data Access and provides some API functions to people who develops OPC server . The people can rapidly develop the server accorded with OPC standard so as to shorten time of the server development. This thesis develops an application of testing server in the basis of the DLL. The application realizes all the interface of OPC Data Access 1.0 and 2. 0.Finally the thesis depicts the testing process that an OPC client application tests the server .The result shows that the server can well realize data communication accorded with OPC standard. The thesisdevolopes a tool kit of OPC server, which provides advantages for the development of OPC server and also for the popularization of OPC standard.