Application Research Of OPC XML Technology In SCADA System

OPC (OLE for Process Control) is designed by OPC foundation for the communication and interoperability of all kinds of automation systems. It is base on the COM/DCOM and the XML technology and builds a set of standard communication interfaces, which makes automation system able to access data from hardware more quickly and efficiently. It also makes all parts of the system able to communicate to each other seamlessly and greatly improves the interoperability and flexibility of automation system. OPC XML-DA specification is the newest member of OPC family and it is designed for cross-platform applications on Internet. It makes the integrations of automation systems in plant floor with enterprise information management systems possible and opens a great new space for the development of OPC specifications.The SCADA system is the automation of the most basic function, because the hardware technique of it is mature and the price is oppositely cheaper, it is applied the most extensively in automation scopes. The paper analyzes the SCADA system that is widely used in process monitoring, points out that the traditional SCADA system has disadvantage in expanding efficiency and integrating with managing system, then discusses the technology characteristic of OPC XML in detail, therefore proposes OPC XML technology to expand the existing SCADA system, gives the detail designing of the whole system, discusses the process of development of OPC XML server. The method adopted is qualified in solving disadvantage in expanding efficiency and integrating with managing system.Followings are the main contributions of this thesis:The thesis studied the problems in the traditional SCADA system, and applied the OPC XML DA in the design of SCADA system, The method adopted is qualified in solving the problems in expanding efficiency and integrating with other system.We developed OPC XML-DA server, and applied it in the SCADA system. This thesis discussed the architecture and development of OPC server and client. By the application of bridge pattern OPC server has great reusability and expansibility.The security is of great importance to OPC server, so this thesis discussed the security design of OPC server thoroughly, and brings forward a security mechanism based on Microsoft .Net Framework and IIS, which offers agile and reliable validation and authorization mechanism.