| As the tightly combination of industrial automation and information technology in1990s, equipment manufacturers of automation system hope to integrate differenthardware equipments and software products of different manufacturers so that eachmanufacturers could implement interoperability, thus the OPC standard and technologywas born.During the last twenty years the OPC technology got a ripid development and hasbeen widely used in production and human’s livelihood. The OPC standards provide abridge between hardware manufacturers and software developers, through the OPCinterface provided by hardware manufacturers, OPC software developers could ignorethe differences among all kinds of hardwares, they could get any information they wantfrom them. Thereby software developers at client end just need to focus on the controlprocess and functional implementation of application software themselves.This paper introduces the background and development of OPC technology. Thendiscusses the details of the whole OPC specifications, the basic theories of ATL, WTL,COM and DCOM that are required for OPC development. The opc synchronouscommunication server and asynchronous communication server based on OPC DA3.0specification were implemented. This paper also implements synchronous andasynchronous access OPC client based on the OPC DA3.0specification. The OPCserver and client were successfully deployed in the centralized control system ofDigital Mine.Besides, this paper also introduces the method of adding all kinds of interfacesunder VC and of registering servers, and puts forward a comprehensive solution for theDCOM configuration when client need to access server remotely with praticalexperience. The OPC server and client which deployed in the Digital Mine runs stablyand effieicent, fully compliant with the expectations of the industry. |
