In ClearSCADA, alarms can be suppressed such that when an alarm is raised on a ‘parent’ item, any alarms raised on items that reference that ‘parent’ item are suppressed.
The primary purpose of alarm suppression is to avoid ‘flooding’ the system with alarms that are a natural consequence of other alarms. When suppression is used, ClearSCADAonly raises alarm(s) for the ‘parent’ item. Any changes in value or state that would usually result in alarms being raised for ‘child’ items are suppressed (omitted from any alarm displays) so as not to confuse operators by displaying other alarms that would otherwise be raised due to original ‘parent’ alarm being active. For more information, see The Effects of Alarm Suppression in ClearSCADA.
You configure any alarm suppression using the fields within the Consequential Alarms section of each database item’s Alarm tab. (The tab exists for any item for which alarms can be raised.)
To configure alarm suppression:
- Use the Type combo box to specify the suppression type. Choose from:
- None—Alarm suppression is not used for alarms raised by this item. The rest of the fields in the Consequential Alarms section are ‘grayed out’ and unavailable for use.
- Consequential—Alarms raised by this item are suppressed should they occur while the Parent Alarm Condition is active for the Parent Alarm Object. The Event Journal record that is generated to indicate that alarms are suppressed states that the reason is due to Consequential alarm suppression.
- Maintenance—This is an alternative to the Consequential option. Select this option if alarms raised by this item are suppressed should they occur while the Parent Alarm Condition is active for the Parent Alarm Object. The Event Journal record that is generated to indicate that alarms are suppressed states that the reason is due to Maintenance mode.
- With an alarm suppression Type other than ‘None’, use the Parent Alarm Object field to specify the database item that is to suppress this item’s alarms. Any alarms are only suppressed if they are raised while the Parent Alarm Object’s alarm status matches the Parent Alarm Condition.
Select the browse button next to the field to display a Reference browse window. Select the required database item from the window.
- Use the Parent Alarm Condition field to specify the specific type of alarm that, when raised by the Parent Alarm Object, will suppress any new alarms that might otherwise be raised by this item.
Select the browse button next to the field to display a Reference browse window. Select the required type of alarm from the window. The list of alarms varies depending on the database item. So, for instance, several types of alarm might be associated with an outstation item, while other types of database item might only have a single alarm type.
- Save the configuration.
For an example that demonstrates how alarm suppression might be configured in ClearSCADA, see Example Configuration.