Primary instance loses connection to PI Data Archive

In cases where failover is configured to ensure a continuous data flow to Data Archive to prevent disruption of operations dependent on the server connection, primary and backup interfaces perform the following operations:

1. If any PI API functions return a value indicating Data Archive is unavailable, UniInt signals that IF-Node1 lost its connection to Data Archive, and IF-Node1 writes a value to its heartbeat point. This value increments from 17 to 31 in a cycle that repeats while IF-Node1 is disconnected.

2. During its next failover cycle, IF-Node2 reads the value in the heartbeat point indicating a failover trigger and stops discarding queued data.

3. At the following failover update, IF-Node2 tries to read the value of the active ID point on Data Archive.

4. For a successful active ID read, IF-Node2 transitions to AssumingControl state and updates the active ID point value to its own failover ID.

5. IF-Node1 reads the value of the active ID for IF-Node2 and immediately assumes backup role.