| In recent years,the traditional OPC specification has been internationally recognized in the field of industrial automation,and widely used in the Supervisory Control and Data Acquisition(SCADA)system.However,with the development of information technology,SCADA systems are not satisfied with the data exchange with equipment and process monitoring in the lower,and gradually extend functions to data management and more complex business logic processing in the upper.Resulting in the growing scale of the system,user requirements for information exchange and sharing are getting higher and higher.On the other hand,the focus of the development of the entire industry turned from the COM technology to the cross-platform web service technology and the SOA technology,leading to OPC technology with COM dependency will lose technical support.The OPC UA specification is a comprehensive upgrade to OPC technology without sacrificing any functionality and performance of traditional OPC specifications.It provides a unified standard for the exchange of data between different automation devices,buses and protocols,and has many technical advantages to meet the requirements of the current SCADA system.This thesis first studies the key technologies in the OPC UA specification used in the SCADA system.According to the needs of SCADA system,design the various node types that make up the address space of real-time database(RTDB),memory organization and other data structures.Furthermore,studies the main modules of the UA SDK,and analyzes the key modules of the SCADA system-real-time data service module and download service module,design and implements real-time data service module and download service module.Finally,the function and performance of the real-time data service module and the download service module of SCADA system based on OPC UA are tested,and the key technologies of OPC UA are displayed by the client.The main contents,methods and achievements of this thesis are as follows:(1)This thesis studies the important theories of OPC UA,including OPC UA data organization models,the OPC UA information model,OPC UA services.OPC UA data organization models have address space,object,variable and node and so on.And the UA SDK key modules are studied on the basis of these theories,which are the key technologies for the development of industrial control systems based on OPC UA.(2)This thesis uses OPC UA data organization models,the information model and type definition methods,and analyzes the needs of SCADA system to design various node types,real-time database memory structure and other data structures using the SCADA system.(3)This thesis analyzes the needs of the real-time data service module.Based on the design of the system node category,the basic class library of SCADA system is realized,and the UA SDK is integrated to realize the real-time data service module,and the function and performance of the module are tested.(4)This thesis analyzes the needs of the download service module.Uses UA SDK main modules and object-oriented to design and achieve the download service module,and the function and performance of the module are tested.Simultaneously,connects the client to display the use of OPC UA key technologies such as base types,address spaces,nodes,references,and services for the SCADA system in the C/S architecture.The OPC UA standard defines a unified data acquisition method,a unified address space and a set of services.The OPC UA server integrates real-time data,historical data,alarm information and events into a unified address space and accesses them through services in a unified service set.The SCADA system based on OPC UA meets the needs of users with the flexibility of data organization,the diversity of data services,the convenience of service communication and the ease of integration of systems. |
