The DeltaV OPC History Server provides the IOPCHDA Server Object, as illustrated below. The ProgID used to create an instance of the DeltaV OPC History Server is "DeltaV.OPCHDAsvr." An instance of the DeltaV OPC History Server (DOPCHDA1.exe) runs on each DeltaV node where the DeltaV Continuous Historian has been enabled if there is a client connected. Each connection to the DeltaV OPC History Server has an instance of an IOPCHDA Server Object. The IOPCHDA Browser Object may only be created by invoking one of the methods in the IOPCHDA_Server interface.
The optional IOPCHDA Client Object may be implemented by client applications needing to be notified when the DeltaV services are stopped. Clients implementing this interface must respond to the ShutdownRequest method in a timely manner.
