Enable, silence, and disable alarms

Alarms can be enabled, disabled, or silenced while an application is running. An object’s alarm state can be set at the Area level, at the container object level, or at the individual object. In addition, individual alarms within a single object can be enabled, silenced, or disabled.

• Enabled: All alarms for an object are reported to client applications and saved as historical data. The enabled state is less restrictive than the silenced or disabled alarm states.

• Silenced: All alarms for an object are detected and logged in the Historian alarm and event history database. Silenced alarms are not logged to the InTouch alarm database, and are not shown in alarm clients displaying current alarms or recent history alarms. The silenced alarm state is more restrictive than the enabled state, but less restrictive than the disabled state.

• Disabled: No alarms for the object are detected. The alarm is return-to-normal until the alarm is re-enabled. The disabled state is more restrictive than the silenced and enabled alarm states. A disabled alarm does not require acknowledgement.

When an alarm state changes from silenced to enabled, the following applies:

• Only the last occurrence of the alarm appears in alarm clients.

• Only the last occurrence of the alarm is logged into the alarm database.

• Only the last occurrence of the alarm is saved to history.

The following figure shows how the different alarm modes affect the different phases of an alarm. In the case of Alarm Suppressed, selected alarms can be filtered out of the InTouch AlarmViewer display by an operator, or programmatically by a script.

To ensure that alarmed attributes always have current data, the alarm feature always registers a reference to the alarmed attribute. This guarantees that Message Exchange never suspends updates for this attribute. Even if alarms are disabled for a particular attribute, the alarmed attribute cannot enter an Advanced Communication Management Suspended state.

The object hierarchy and alarm states determine the final alarm condition of an object.

• An Area object’s alarm state determines the alarm state for all alarms of objects that belong to the Area.

  

• The most restrictive setting within an object hierarchy determines the object’s alarm state.

  

• When an individual object alarm is silenced or disabled, it applies only to that alarm and not to other alarms belonging to the object.

  

  The alarms on any contained object are not affected. The disabled or silenced state of an individual alarm does not propagate downward through the object hierarchy to the alarms of any contained or assigned object.