User Manual

Alarm management
Alarm suppression
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162 | 353 CM110664en_07
For more information on function block AS_STA, see:
Desigo Firmware blocks, automation level, Overview (CM110749)
Desigo Vxx Firmware blocks (CM110729)
Desigo room automation supports the suppression of all alarms of an
automation station. To do this, it uses the device infrastructure objects
CommonEvent and CommonEventEnrollment.
Hierarchical alarm suppression
Hierarchical alarm suppression allows for suppressing alarms of a plant, partial
plant, aggregate, component, or subcomponent. Hierarchical suppression is
based on suppressing alarms of any part of a partial tree in the technical
structure.
For Desigo PX hierarchical alarm suppression is carried out via the Alarm
Collection (CMN_ALM) object. CMN_ALM comprises all alarmable BACnet
objects as a group on the same or lower hierarchies in the technical view. Thus,
CMN_ALM allows for controlling alarm suppression for all alarmable BACnet
objects of a group.
Alarm suppression is controlled via pin SupEvt. The following values are defined
for SupEvt:
● true: Alarmable BACnet objects of a group do NOT send BACnet event
notifications.
● false: Alarmable BACnet objects of a group send BACnet event
notifications.
Desigo room automation supports the hierarchical suppression of alarms. It
uses the CommonEvent and CommonEventEnrollment objects.
The CommonEvent object aggregates the alarm state of all BACnet objects on
the same or the lower hierarchy levels of the technical view.
The CommonEventEnrollment object monitors the CommonEvent object. The
hierarchical alarm suppression can be turned on or off in the
CommonEventEnrollment object.
Specific alarm suppression
All alarmable BACnet objects allow for specific suppression. Each alarmable
BACnet objects offers pin EnEvt for this type of alarm suppression.
The following values make sense for EnEvt:
● (False, False, False): The object sends NO BACnet event notification.
● (True, True, True): The object sends BACnet event notification.
Value combinations with True and False for EnEvt should be avoided.
Alarm suppression exceptions
A possible application is to activate alarm suppression during plant
maintenance. Vital alarms must be excepted from alarm suppression.
For Desigo PX exceptions can be defined for hierarchical alarm suppression
with CMN_ALM.
Function block CMN_ALM has pin EnSupEcp. This exception specifies if
exceptions are possible within the alarmable BACnet objects of the group. The
following values are defined for EnSupEcp:
● true: Exceptions for alarm suppression within the group of alarmable
BACnet objects are considered.
● false: Exceptions for alarm suppression within the group of alarmable
BACnet objects are NOT considered.
Each alarmable BACnet object can be exempted from hierarchical alarm
suppression with CMN_ALM. To do this, each alarmable BACnet object has pin
SupEcpt. The following values are defined for SupEcpt:
● true: The object is considered as an exception for alarm suppression.
● false: The object is NOT considered as an exception for alarm suppression.