Open Opc-based Scada Systems Research And Design

The SCADA system which have extensive application field, so called supervisory control and data acquisition, can apply to supervisory control N data acquisition and process control of electric power systenu water supply systenu petroleum industry^ chemical industry etc. The SCADA is producing process control system and auto-dispatch system based on computer technology. It can implement data collection^ device control^ measure> parameter adjustment and all kind of signal alarming by supervise and control the running device on spot.The technology advancement in SCADA system, which is developing and consummating continually, would not be stopped from the beginning. The basic control function for process is intended to embed in intelligent instrument and the meanings of process control change. The SCADA is needed further to solving the problem of performance supervisory and fault diagnosis. Furthermore, the request of customer to control software and local device is heightened too. So, The new require for the development of process control application is putted forward. Only the process control application with strong function > open architecture , ability of co-operation is success system.The OPC, so called OLE for Process Control, is a specification and technology standard and was designed to solve the communication ' s problem of application software and drivers. It adopt the architecture of C/S, which is based on the technology in Microsoft's OLE/COM, and can offer the hardware manufacturer and the developer of application software a set of standard interface. And, the "plug and play" and no-sew connection can be implemented.The paper apply the OPC technology to the architecture of SCADA system, applications can call and control each other using the standard interface of OPC. So, the expansibility of system and the compatibility of integration are increased greatly, at the same time, the reliability and stability of software running are also heightened and the upgrade and maintenance of system are convenient. Furthermore, the design of system adopt template library and the level of code reusing is heightened, so the programmer can establish rapidly the collection of class library andfunction. The implementation of template library is to facilitate the more large-scale development of OPC Server.