Shared Memory Based Research And Design Of OLE Process Control3.0Server

With the computer information technology and automation of informationtechnology in the field of industrial control, and computer program developmenttechniques and other aspects of the rapid development of industrial computermonitoring system from the previous process-oriented design is increasinglyevolved into an object-oriented design, and even a client/server model gradually tothe browser/server mode shift, PC real-time monitoring technology from theeighties and nineties, centralized way to the real-time monitoring of distributedreal-time monitoring of the direction to move closer. OPC industry standarddeveloped in recent years for the control system data monitoring, OPC industrystandard has now been upgraded to3.0standard, mainly for the operating systemcommunicate with each other without the use of an application for the developmentof this industry has significant meaning.This topic based on the shared memory of the generic OPCDA3.0serverresearch, the field data to a OPC server, client oriented and open with data accessstandard communication interface, so that the client application development, so asto achieve the purpose of data communication. The OPCDA server because the datasource structure changes often needs to be tailored to the specific project fordevelopment, to adapt the existing software structure. This makes the OPCDA serverreusability greatly reduced.Using shared memory for three party programs and server data exchange center,the OPCDA server data interface using standard data structure. Only need third partyprograms will specify the data into the shared memory can be, the OPCDA serverwill periodically polling the shared memory to obtain the update data.Shared memory based generic OPCDA3.0server consists of data cache, objectand the client interface, interface and configuration module and a shared memorydata interface module.Real time data cache for storing OPC Item Value, from field control stationreads the get. The future, from the control station to obtain the data by communication drive according to the specified data structure stored in the sharedmemory.Server object in accordance with the OPC standard design Server object, Groupobject and Item object. The server to the client to provide OPC custom interface.Interface configuration module is responsible for managing the OPC serverinterface and configuration information.Shared memory data interface module is read from the shared memory systemstructure data, via a configuration module IO information configured as Item, andread from the shared memory real time data cache.Based on the background of Industrial Control Technology, OPCDA server andshared memory from the knowledge of other aspects of the architecture, introduce ashared memory based OPCDA3.0generic server design and implementation. First,to clarify the shared memory based OPCDA3.0research proposed general-purposeserver, meaning and content of the study system. Then briefly elaborated based onshared common OPC server software within the course of the study OPC3.0DataAccess Server and related technologies such as shared memory Introduction andprinciples. Major topics include the detailed design of the OPC server data structuredesign, including server object design, object design and item group object structuredesign, elaborated from the direction of the data structure standard OPC technologybased on shared principles and common OPC server software within the datastructure design. Then for the design module based on shared common within theOPC server software OPC3.0Data Access Server framework design, and sharedmemory data structures and workflow design.