Base On The Specefication Of OPC Data Access

OPC is such a standard that we need.OPC means OLE(ObjectLinking and Embedding) for Progress Control.OPC was put forward insolving communication between application software and vary drivers ofdevices.It makes the work more efficient.Consequently,the repeatedexploitations are reduced in the integrated system.OPC specification willbe a developmental aspect about process automation's communicationnormal for future. In the master student project the Component Object Model as OPCnut technology and its applications detail about the realize,issuance andestablish method of COM component.The uses of connection pointertechnology and Tear-off technology ,the program for OPC interface wasaccomplished . According to the OPC Data Access Specification, the OPC of DataAccess with the basic function has been developed, which cancommunicate with OPC Client of the third party.This server can completesync read, async read or async subscription, and sync write or asyncwrite.