Alarm Lifecycle

The Nexus Platform alarm management system adheres to the ANSI/ISA-18 standard for alarm management. This standard defines a lifecycle for alarm states to ensure consistent handling, visibility, and operator response.

Each alarm follows a well-defined sequence of states from activation to resolution, enabling operators to track both the current status and the history of an alarmed condition. Understanding this lifecycle is essential for effective alarm handling, acknowledgment workflows, and system reliability.

Each alarm follows a four-state model:

Alarm state	Acknowledged	Description
IN ALARM	NOT ACKNOWLEDGED	A condition has entered an alarm state and has not yet been acknowledged by an operator.
IN ALARM	ACKNOWLEDGED	The alarm condition is still active, but has been acknowledged by an operator.
NORMAL	NOT ACKNOWLEDGED	The condition has returned to normal, but the alarm has not yet been acknowledged by an operator.
NORMAL	ACKNOWLEDGED	The alarm condition has cleared and has been acknowledged. The alarm is considered resolved.

The alarm lifecycle and its transitions are illustrated below:

Transitions between alarm states

These states are visually represented in the UI using color-coded labels and badges.

Initially, all alarms are in the Normal Acknowledged state (RTNxACK). This state indicates that the alarm is not currently active and has not been active since it was last acknowledged by an operator. In this state, the alarm is not visible in the alarm list.

When an alarm condition occurs, the state moves to the Alarm Unacknowledged state (ALARMxUNACK ) making is visible in the alarm list.

Active alarm, that has not been acknowledged

From here, the alarm condition can either disappear, moving to state (RTNxUNACK) or the operator can acknowledge the alarm, moving to state (ALARMxACK).

Example of unacknowledged alarm returning to normal, and active alarm that is acknowledged.