First-out alarm

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A first-out alarm is an alarm that indicates in some manner that it was the first of a series. This is necessary in circumstances such as an automatic trip or shutdown of equipment, where many alarms will annunciate as a result of a shutdown. The first-out alarm will clearly identify the root cause of the trip or shutdown.

External links[edit]

ISA Alarm Standard 18.1 Annunciator Sequences and Specifications