Study On OPC Technology Based On Ethernet Control Network

With the desirability of industry control interests to openness and standardization of industry control system and requiremet of enterprise information integration becoming more and more stronger,the leading worldwide automation company and hardware&software suppliers supported with technology by Microsoft created an industrial standard-OPC specification.The purpose of OPC is to standardize the interface of software and hardware,and to improve the openness of system.OPC interface specification is studied deeply and detailed in this thesis.OPC inner mechanism based on COM/DCOM and interaction of Client/Server system are analyzed.The development consists of two parts:the development and design of OPC Client;The development approach and its practice of OPC.Several difficulties such as multi-thread programming,OPC interface's realization and multi-view displays are overcomed during the OPC Client's development.The OPC Client can connect multi OPC Server at the same time .manage them,and maintain data. With the help of Microsoft ,the development of OPC Server is focus on building a uniform developing platform first,then I/O DLL based Ethernet card is developed.The OPC Server based on Ethernet is realized.Finally,the whole performance tests of Client and Server are carried out.The results proved that the OPC DA Client/Server system developed conform to the OPC standard specification It unified the communication between the industrial fieldbus devices level and the process management level.It provides a good way for further information integration with enterprise management level. .