Alarm sub-states

A multi-state alarm includes a range of alarm sub-conditions.
For example, an analog alarm typically has several limits.

• A High and Low threshold set the boundaries for the normal operating range.

• HiHi and LoLo limits mark the extreme deviations from the normal range of values.

A boiler temperature level can be in the alarmed condition for any one of these sub-states. The boiler temperature can also transition between any two sub-states while continuing to remain in the overall alarmed condition.