Redundancy

This chapter deals with the case that the WinCC OA OPC HDA server is running in a redundant WinCC OA system.

Redundant OPC HDA Server

If a redundant OPC HDA server should be used, the server must be installed and configured on both systems. In case of a query the WinCC OA systems will return identical values to the client. Queries must either be sent to both server or to the currently active server.

Single OPC HDA Server

If a single OPC HDA server should query values from both systems of a redundant project, a connection to both WinCC OA projects must be established. Therefore the following config entry must be added inside the projects that should connect to the OPC HDA server:

[opchdasrv]

connectToRedundantHosts = 1