Core Configuration Guide - The Effects of Suppression on Alarm Displays (Defining an Item or Group's Alarm Properties)

The Effects of Suppression on Alarm Displays

The tables in this topic explain the effects that 'By Alarm State' and 'By Expression' alarm suppression have on the entries in alarm displays.

'By Alarm State' suppression

The table below indicates how the alarm condition that triggers 'By Alarm' alarm suppression affects the entries in alarm displays, such as Alarms Lists and the Alarm Banner.

The two columns on the left relate to activity on the 'parent' database item (the item that triggers the suppression). The columns on the right relate to alarm activity on each 'child' database item (the items on which alarms are to be suppressed).

Activity on Parent Database Item		Alarm Activity on Child Database Items
Parent Alarm Activity	Entry in Alarm Displays	Child Alarm Activity	Alarm Status	Entries in Alarm Displays
No active alarms	---	Any alarms	Unacknowledged Uncleared/ Acknowledged Uncleared/ Unacknowledged Cleared	VISIBLE
Alarm that triggers alarm suppression raised	VISIBLE	The effect on the alarms of child database items on which the 'Suppress Pre-existing Alarms' property is disabled:
		Existing alarms that were raised pre-suppression	Unacknowledged Uncleared/ Acknowledged Uncleared	VISIBLE
		Alarms that cleared pre-suppression, which remain unacknowledged (Geo SCADA Expert automatically acknowledges any alarms that have already cleared when suppression comes into force)	---	---
		Existing alarms, raised pre-suppression, which have been acknowledged while suppression is in force	Acknowledged Uncleared	VISIBLE
		Alarms raised while suppression is in force	Unacknowledged Uncleared	Suppressed (not shown)
		Alarms raised while suppression is in force and which have cleared while suppressed (Geo SCADA Expert automatically acknowledges any alarms that are raised then clear while still suppressed)	---	---
Alarm that triggers alarm suppression raised	VISIBLE	The effect on the alarms of child database items on which the 'Suppress Pre-existing Alarms' property is enabled:
		Existing alarms that were raised pre-suppression	Unacknowledged Uncleared	Suppressed (not shown)
		Existing alarms that were raised pre-suppression	Acknowledged Uncleared	VISIBLE (This is by design, as an acknowledged alarm indicates that operators have been investigating the cause and might want to check that the abnormal condition that caused the alarm does clear.)
		Alarms that cleared pre-suppression, which remain unacknowledged (Geo SCADA Expert automatically acknowledges any alarms that have already cleared when suppression comes into force)	---	---
		Alarms raised while suppression is in force	Unacknowledged Uncleared	Suppressed (not shown)
		Alarms raised while suppression is in force and which clear while suppressed (Geo SCADA Expert automatically acknowledges any alarms that are raised then clear while still suppressed)	---	---
Alarm that triggers alarm suppression cleared, 'Unsuppress Delay' in force	VISIBLE (Unacknowledged Cleared)/ --- (once acknowledged)	Alarms raised while the 'Unsuppress Delay' is in force and which clear while that delay remains in force (Geo SCADA Expert automatically acknowledges any alarms that are raised then clear while still suppressed)	---	----
	VISIBLE (Unacknowledged Cleared)/ --- (once acknowledged)	Any remaining alarms that were raised either during the suppression or during any 'Unsuppress Delay' that occurred following that suppression.	Unacknowledged Uncleared/ Acknowledged Uncleared	Suppressed (not shown)
Alarm that triggers alarm suppression cleared, 'Unsuppress Delay' expired	VISIBLE (Unacknowledged Cleared)/ --- (once acknowledged)	Any alarms, regardless of whether they were raised pre-, post-, or during suppression, or during any 'Unsuppress Delay' that occurred following that suppression.	Unacknowledged Uncleared/ Acknowledged Uncleared	VISIBLE*
Different type of alarm raised**	VISIBLE	Any alarms, regardless of whether they were raised before or while the parent object’s alarm is active	Unacknowledged Uncleared/ Acknowledged Uncleared/ Unacknowledged Cleared	VISIBLE

'By Expression' suppression

The table below indicates how the expression criteria that triggers 'By Expression' alarm suppression affects the entries in alarm displays, such as Alarms Lists and the Alarm Banner.

The column on the left relates to activity on the 'parent' database item (the item that triggers the suppression). The columns on the right relate to alarm activity on each 'child' database item (the items on which alarms are to be suppressed).

Value of the Parent Alarm Tag	Alarm Activity on Child Database Items
Value of the Parent Alarm Tag	Child Objects	Alarm Status	Entries in Alarm Displays
Causes the expression to evaluate as 'False' (no suppression)	Any alarms	Unacknowledged Uncleared/ Acknowledged Uncleared/ Unacknowledged Cleared	VISIBLE
Fulfills the expression criteria	The effect on the alarms of child database items on which the 'Suppress Pre-existing Alarms' property is disabled:
	Existing alarms that were raised pre-suppression	Unacknowledged Uncleared/ Acknowledged Uncleared	VISIBLE
	Alarms that cleared pre-suppression, which remain unacknowledged (Geo SCADA Expert automatically acknowledges any alarms that have already cleared when suppression comes into force)	---	---
	Existing alarms, raised pre-suppression, which have been acknowledged while suppression is in force	Acknowledged Uncleared	VISIBLE
	Alarms raised while suppression is in force	Unacknowledged Uncleared	Suppressed (not shown)
	Alarms raised while suppression is in force and which have cleared while suppressed (Geo SCADA Expert automatically acknowledges any alarms that are raised then clear while still suppressed)	---	---
Fulfills the expression criteria	The effect on the alarms of child database items on which the 'Suppress Pre-existing Alarms' property is enabled:
	Existing alarms that were raised pre-suppression	Unacknowledged Uncleared	Suppressed (not shown)
	Existing alarms that were raised pre-suppression	Acknowledged Uncleared	VISIBLE (This is by design, as an acknowledged alarm indicates that operators have been investigating the cause and might want to check that the abnormal condition that caused the alarm does clear.)
	Alarms that cleared pre-suppression, which remain unacknowledged (Geo SCADA Expert automatically acknowledges any alarms that have already cleared when suppression comes into force)	---	---
	Alarms raised while suppression is in force	Unacknowledged Uncleared	Suppressed (not shown)
	Alarms raised while suppression is in force and which clear while suppressed (Geo SCADA Expert automatically acknowledges any alarms that are raised then clear while still suppressed)	---	---
Changes to a value that causes the suppression to clear, 'Unsuppress Delay' in force	Alarms raised while the 'Unsuppress Delay' is in force and which clear while that delay remains in force (Geo SCADA Expert automatically acknowledges any alarms that are raised then clear while still suppressed)	---	----
	Any remaining alarms that were raised either during the suppression or during any 'Unsuppress Delay' that occurred following that suppression.	Unacknowledged Uncleared/ Acknowledged Uncleared	Suppressed (not shown)
Has a value that causes the suppression to clear, 'Unsuppress Delay' expired	Any alarms, regardless of whether they were raised pre-, post-, or during suppression, or during any 'Unsuppress Delay' that occurred following that suppression.	Unacknowledged Uncleared/ Acknowledged Uncleared	VISIBLE*

* The date and time assigned to any alarms that were suppressed but become visible once suppression is no longer in force varies, depending whether the Use Visible Time As Alarm Active Time feature is enabled. If the feature is enabled, the alarm entries are time stamped with the date and time that they became visible post-suppression; if the feature is disabled (the default on most systems), the alarm entries retain their original time stamp (indicating the alarm’s original receipt time or occurrence time).

** Only some types of database item support more than one type of alarm.

Further Information

Alarm Status.

Activities that Occur when an Alarm is Raised.

Define whether the Visible Time is used as the Active Alarm Time.

For more information about either type of alarm suppression, see Configure any Alarm Suppression Requirements.