INFO
For most alarms the Trigger level is set and cannot be changed. Custom I/O alarms can be configured for High or Low
setting of the Trigger level.
4.2.9 Auto acknowledge
When Auto acknowledge is selected, the alarm is immediately marked as acknowledged in the alarm display when the alarm is
activated.
Alarms that have a Latch configured, even if automatically acknowledged, still require unlatching by the operator.
4.2.10 Latch
You can configure a Latch on any alarm. When an alarm with a Latch is activated, the alarm Action remains in force until the alarm is
acknowledged and then reset (unlatched). Alarm latching provides an extra layer of safety.
For example, you can create a low oil pressure alarm with a latch and a Trip generator breaker and shutdown engine alarm action.
Then, if there is low oil pressure, the controller trips the breaker and stops the engine. The engine remains stopped and will not be
able to start until the alarm is reset.
CAUTION
Enabling a Latch on an alarm is not enough for safety protection. To be effective, the alarm must also be Enabled, and the
alarm Action must be effective against the unsafe situation. For example, a Latch on an alarm with the action Warning
offers little extra protection.
4.2.11 Suppress action parameter
All controllers
For all controller types, an alarm action is suppressed when Suppress action is Enabled for the alarm, and the function Alarm
system > Additional functions > Suppress alarm action is activated by a digital input, PICUS, Modbus, and/or CustomLogic.
If the alarm action is suppressed, when the alarm is activated, the alarm is shown in the alarm handling system, but the alarm action
is only Warning.
EMERGENCY genset controller
If there is a blackout, then the EMERGENCY genset controller must ensure that power is restored to the emergency busbar as soon
as possible.
For the EMERGENCY genset controller, when Suppress action is selected for an alarm, the alarm action is suppressed during the
blackout recovery. The alarm is shown in the alarm handling system, but the alarm action is only Warning.
More information
See Power management, Blackout for more information about blackout recovery.
4.2.12 Alarm test
The alarm test activates the alarm and its alarm action. You can use the alarm test parameter to test individual alarms, for example,
during commissioning.
CAUTION
Alarm tests activate alarm actions, some of which can force the system to switchboard control, trip breakers, create a
blackout, and shut down engines. Use extreme care when performing alarm tests during normal operation.
Alarm tests of individual alarms can be stopped one at a time using the parameter, or at the same time using the Stop test button on
the Alarms page in PICUS.
DESIGNER'S HANDBOOK 4189340911K UK Page 101 of 521
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