PI Interface for OPC HDA Overview
The PI Interface for OPC HDA is an OPC HDA COM interface for bi-directional data transfer between an OPC HDA Server and an OSIsoft PI System. The interface accesses data from the OPC HDA Server, providing historical data retrieval. The design of the interface allows running multiple instances of the interface simultaneously. Each interface is able to connect with only one OPC HDA Server, which may be on the same or a different machine. More than one interface may be configured to connect to the same OPC HDA Server. The interface may reside on a PI home node or a PI Interface node.
The PI Interface for OPC HDA is available in two different options: a read-only option and a read-write option. The read-only option is strongly recommended for installation if updates to the data source are not needed (that is, use of output points is not needed). The read-only option provides the best defense against accidental or malicious changes to the control system because it cannot write to the data source. The read-write option retains the ability to write data to the data source (using output points) and is an update to versions 188.8.131.52 and earlier installations of this interface. With the exception of whether or not output points are supported, the functionality of both options is the same.