Configure multiple watchdog PI points

If you must assess several OPC items to determine availability (such as when the OPC server can report on the availability of the back-end data sources), configure multiple OPC watchdog PI points. The sum of the values of the OPC watchdog points determines whether the server is considered active. The interface initially assigns each watchdog point a value of 1 and recalculates the total whenever it receives a new value for one of the points. If the sum goes below the specified minimum, failover is triggered.

1. Create PI points and map them to the OPC items that you consider reliable indicators of OPC server status. For each point, set location3 to 3 for polled points or 4 for advise points.

2. Using PI ICU, go to the OPCInt > Failover > Server Level page and set the Multiple Watchdog Tags Trigger Sum field to the minimum acceptable total of the values of the watchdog points.

3. Verify that failover is triggered if the total of the values drops below the specified minimum:

   1. Start the OPC servers and the interface.

   2. Manually set the values of the OPC items.

   3. Examine the AF SDK log or check the Active Server point to determine whether the interface failed over to the backup OPC server.