Failover timing

When failover is triggered, PI Interface for OPC DA must quickly recognize that the current OPC server is no longer available and determine whether the backup OPC server is available. To configure failover efficiency in the PI ICU, you can adjust the following settings on the OPCInt > Failover > Server Level page:

• Switch to Backup Delay (/FT=#)

  Specifies in seconds how long the OPC interface tries to reconnect to the current server, before failing over to the other server and, if less than 30, how often the interface checks the server state.

• Number of Interfaces on this Node (/NI=#)

  /ni=# (Optional) Specifies the number of instances of the interface running on this node. This is used in conjunction with the FT parameter to determine how long to wait before initiating server-level failover.

• Wait for Running State (/SW=#)

  Specifies how many seconds the interface waits for the server to enter the RUNNING state before failing over to the other server. By default, the interface waits indefinitely for the server to enter the RUNNING state. Note that OPC servers vary significantly in the time required to enter the RUNNING state.