User Manual

Alarm management
Alarm functions
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The alarm remains locked until the fault has disappeared and has been
acknowledged and a reset has been carried out, e.g.:
The burner system is restarted when the service engineer has acknowledged
the alarm, cleared the fault and reset the alarm. The alarm state of every alarm-
generating object is managed within the object itself. The state machines
above illustrate this for each of the alarm functions.
The alarm function simple message is the same function as the simple alarm.
State transitions, however, are not indicated as events, but alarms.
For HVAC applications and response in the system, the functionality is identical
to simple alarm: Simple alarm without acknowledgement of incoming and
outgoing faults. The only difference is EventNotification as alarm or event.
Any alarm function under BACnet can be used. The following behavior can be
defined for customized alarms:
● EventNotification can occur as either event or alarm
● Acknowledgement: For each change of state (TO-OFFNORMAL, TO-
NORMAL, and TO-FAULT) can be defined whether or not an
acknowledgement is required.
This feature is used to represent the acknowledgement status, or to handle
information about which state transitions currently still require
acknowledgement. The value of [AckTra] is based on the alarm function, the
current [EvtSta] and the monitoring of acknowledgements already received.
[AckTra] consists of three flags, one each for TO-OFFNORMAL, TO-NORMAL
and TO-FAULT. The flags have the following meanings:
● The flag is always FALSE when there has been a relevant state transition
and an acknowledgement is required, because this is a requirement of the
alarm function and no acknowledgement has yet taken place.
● The flag is TRUE when no acknowledgement of the state transition is
required. This may be the case because the alarm function does not require
acknowledgement, or because no state transition has occurred, or because
a state transition that has occurred has already been acknowledged.
Time of the last acknowledgement (time stamp).
Simple message
Customized alarm
[AckTra] Acknowledged
transitions
[TiAck] Time of
acknowledgement