enunciator

An enunciator, sometimes called an annunciator, is a device or subsystem that communicates the status of equipment or processes. In industrial and building automation, an enunciator panel provides visual or audible indications of faults, alarms, or normal operating conditions. The term derives from enunciate, meaning to announce.

Enunciators are typically visual, using indicator lamps, LEDs, or mechanical pointers mapped to sensors. Audible enunciators use horns, buzzers, or voice messages to announce events, sometimes with programmable priorities to emphasize critical alarms.

Modern enunciators are often part of distributed control systems, SCADA, electrical switchgear, or facilities management networks. They may be connected to PLCs or digital I/O and can be remote or mounted near the equipment they monitor. Features may include time stamping, alarm logging, reset control, and priority-based annunciation to reduce alarm fatigue.

In aerospace, railway signaling, and data centers, enunciators help operators quickly identify and respond to essential conditions. Historically, enunciator panels consisted of banks of lamps and switches; digital and networked enunciators now provide text displays and remote annunciation.