OPC HDA Client - Redundancy

Notes regarding redundancy

  • If the OPC HDA Client is operated in a redundant WinCC OA project, it must be started on both redundant hosts. Both clients establish a connection to the external OPC HDA server and display the server information. Only the active host sends historical queries.

  • Both clients use their own internal server connection data points of type _OPCHDAServer. Therefore in a redundant project there are redundant server connection data points with postfix "_2". These data points are automatically created by the OPC HDA client configuration panel.

  • If the redundant project is operated in split mode, both clients establish a connection to the OPC HDA server and send historical queries to the server.

  • In case of a redundancy switch during an ongoing OPC HDA query the concerned query must be started again via the internal server data point.