Acknowledge
Alarm 1
Acknowledge
Alarm 2
Alarm 1
Alarm 2
Horn
(1)
(3)
(2)
The horn output is deactivated when both alarms are acknowledged (even though both alarms are still active).
Siren
The horn output is activated when one or more alarms are active.
The horn output is deactivated when there are no active alarms.
The horn output is affected when a new alarm becomes active. To alert the operator to the new alarm, the horn output is deactivated
for the time in the
Minimum down time
parameter, and then activated again. If the horn output is connected to a siren, this gives a
wailing effect every time there is a new alarm.
Each time the horn output is activated, the horn output must remain activated for the time in the
Minimum up time
parameter. This
stops multiple new alarms from deactivating the horn output.
Table 4.14
Siren parameters
Parameter
Default
Notes
Reset when new alarm
Enabled
Minimum down time
0 s to 1 h
Required
Minimum up time
0 s to 1 h
Required
De-energise when all alarms are acknowledged
Not enabled
INFO
Acknowledging alarms (or not acknowledging alarms) has no effect on the horn output.
Siren example
Min. uptime
Min.
downtime
Min. uptime
Alarm 1
Alarm 2
Horn
(1)
(3)
(2)
The horn output is deactivated for the
Minimum down time
when
Alarm 2
becomes active. To fulfil the
Minimum up time
requirement, the horn output remains active for a short time after both alarms become inactive.
DESIGNER'S HANDBOOK 4189340911K UK
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