Understand alarm acknowledgement models

The InTouch HMI supports three models of alarm acknowledgement:

• For condition-oriented alarms, an acknowledgment counts against all entries into the alarmed state up to the time of the acknowledgment.

• For expanded summary alarms, an acknowledgment is only for a particular transition, whether to an alarmed state, to a sub-state, or a return to normal. All transitions into different alarm sub-states must be acknowledged before the overall alarm is considered acknowledged.

• For event-oriented alarms (as in OPC), an acknowledgment is accepted only if it refers to the most recent activation event.