A duplicate alarm is an alarm instance sent by an asset that has the same name as a previous alarm instance sent by the same asset. The previous alarm instance must still be a "current" alarm (that is, not closed) for a new instance to be considered a duplicate.
Handling of duplicate instances of alarms can be enabled or disabled by your Platform administrator.
When duplicate handling is disabled, the Platform handles duplicates as follows:
The current alarm is moved to Historical Alarms, in its current state.
The new alarm instance becomes the "current" alarm and is given the state, "Started." Effectively, the new alarm instance replaces the current one.
When Alarm duplicate handling is enabled, the Platform handles duplicates as follows:
The state of the new alarm instance is set to "Duplicate," and the alarm instance is sent directly to Historical Alarms. While all the data that came in with the duplicate alarm instance is retained, the alarm instance is not available for any business rules. For example, if you have configured an expression rule to run when this alarm is received, a duplicate instance of the alarm does NOT cause the expression rule to run.
No change occurs for the current alarm. If the new alarm instance reports a different severity for the alarm or if a different data item or data item value is sent in, the information is stored with the duplicate alarm instance. Note that the state of the current alarm must be Started, Acknowledged, or Escalated for a new instance to be treated as a duplicate.