毕业论文--OPCDA客戶端的研究.docVIP

PAGE PAGE I摘 要OPC全称是OLE for Process Control，即过程控制中的对象链接嵌入技术。OPC技术是基于Microsoft的COM/DCOM(组件对象模型/分布式组件对象模型)技术所要求的功能，制定的一个开放和互用式的工控行业的软件接口标准，在当今过程控制领域，是一种非常流行的数据交换技术，是实现控制系统现场设备级与过程管理级信息交互、实现控制系统开放性的中间件技术。OPC技术采用Client/Server模式，规定了OPC Client与OPC Server之间遵循标准的接口。OPC服务端一般由控制设备的生产厂商，将硬件设备驱动程序和通信程序封装成独立的OPC服务器，向OPC客户端实时地提供数据。OPC客户端由使用设备的客户自己开发，可以不包含任何通讯接口程序，不必关心底层的硬件设备特性，也不必考虑软硬件如何通讯，只要遵循OPC规范，就能够从OPC服务器中获取数据，从而实现数据的灵活配置和多种系统的真正集成。由于OPC服务端与客户端之间的接口是标准的，因此可以开发出通用的OPC客户端，使不同的应用访问同一台设备或使同一个应用访问不同的设备。论文首先介绍了OPC技术产生的背景，以及它的主要特点与发展状况，深入剖析了其核心COM/DCOM技术。然后重点分析了OPC数据访问规范及OPC客户端与服务器的通信机制，介绍了如何用VC++开发客户端程序。关键词：OPC；COM；客户端；数据访问规范Abstract OPC is the generic OLE for Process Control,literally translated as the Object Linking and Embedding technology in process control.OPC specification is an open and interoperable software interface standards in the field of process control,based on the functions required by Microsofts COM(Component Object Model)and DCOM(Distributed Component Object Model)technology.Today,in the field of processcontrol,it is a very popular data exchange technology and the middleware technologythat realizes information exchange between open system field equipment in controlsystem and process management level,and lets the control system to be an open system.OPC specification uses Client/Server mode,and defines the standard interface between OPC Client between OPC Server.In the OPC Server end,the control equipment manufacturers package the hardware device drivers and the communication program to be an independent OPC server providing real-time data to OPC Client.The OPC Client developed by customers who use the equipment is able to obtain data from the OPC server as long as following the OPC data interface protocol,also it may include no communication interface program,does not have to care about the hardware characteristics of the bottom,has no need to consider how to communicate between hardware and software.Thus it realizes the integration of flexible configuration of