Alarms

Definition

Alarms are constructs that indicate that manual intervention is necessary to correct a malfunction in a system or initiate a protective shutdown of a system to prevent damage (for a much for through treatment of alarms considering reading Hollifield and Habibi's 'Alarm Managment Handbook').

The Framework provides the following alarm types:

• Discrete alarm (Alarm) - Used for representing discrete alarms (on/off).
• Analog Alarm (AlarmAnalog) - Used for representing when an Analog point exceeds a threshold.

Alarms come with various properties:

• description - a short human readable description of the alarm to be displayed on an alarm annunciator
• consequences - a longer human readable description of the negative consequences and the time frame that those consequences will take to manifest that will result from the alarm conditions.
• more_info - background information for the alarm referencing any pertinent drawings or manuals that will assist in remediating the alarm.
• On delay (delay_on) - Requires that the alarm input be high for a given number of seconds before it is active. Useful for preventing alarm chatter.
• Off delay (delay_off) - Requires that an alarm input be low for a given number of seconds before it is reset. Useful for preventing alarm chatter.