Following acceptance of the alarm the buzzer will silence and the common alarm relay is deactivated.
Pressing reset will clear the alarm and return the Control Panel to the normal state.
3.12 BACKUP ALARM
The Backup Alarm is a hard-wired link from each Detector installed on the system and operates
independent of the system software. This facility will allow any Detector which sees an oil mist level of
1.6mg/l up Alarm. This will result in the operation of the buzzer, Alarm LED
and Common Alarm Relay at the Control Panel. The backup alarm relay in the Junction Box will also be
activated; the Backup Alarm will also override any Detector or Detectors that are isolated.
Whilst any Detectors are in a Backup Alarm condition the Accept key is inoperative until the oil
mist level drops below 1.6mg/l.
It is possible for a healthy Detector to produce a Backup alarm if the level of oil rises very rapidly.
NOTE - The Backup Alarm will not operate the Slowdown/Shutdown Relay
3.13 RELAY OPERATION
Communication of alarm and fault conditions between the OMD Mk6
Management System (AMS) is via a series of volt free contact relays. Individual relays are provided for
Slowdown/Shutdown Alarm, one per engine, Common Alarm and Fault. For each output connections are
provided to the relay common, normally open and normally closed contacts providing the flexibility to
meet the interface requirements of the AMS.
The actions of the relays are detailed below:
The Fault Relay is normally activated and de-
activated when a fault occurs on the Control
Panel or Detectors.
In the event power is lost to the Control Panel the
relay is de-activated ensuring a fault is indicated
to the AMS.
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