ANALOG INPUT ALARM EVALUATION PRINCIPLE
6.14.1 Alarm handling
ï‚· There are two different alarm categories regarding the period when the alarms are evaluated.
The category is selectable for alarms assigned to binary/analog inputs and fixed for built-in
alarms. The categories are the following:
1) The alarm is evaluated all the time when the controller is switched on.
2) The alarm is evaluated only when the engine is running. This type should be used
for e.g. oil pressure. These alarms begin to be evaluated after the engine has been
started with the delay given by the setpoint ProtectHoldOff.
3) The alarm is evaluated only when the generator is excited. These alarms begin to be
evaluated after the engine has been started and Max Stab Time has elapsed or the
GCB has been closed. They remain evaluated until cooling has finished. Only
Generator under/overvoltage, Generator voltage unbalance and Generator
under/overfrequency belong to this category. This category is not configurable to
binary and analog input alarms.
ï‚· If an alarm is being evaluated and the appropriate alarm condition is fulfilled, the delay of
evaluation will start to run. The delay is adjustable by a setpoint (in the case of built-in alarms,
analog input alarms) or is fixed to 500ms (in the case of binary input alarms). If the conditions
persist, the alarm will activate. The alarm will not activate if the condition is dismissed while
the delay is still running.
ï‚· After pressing the Fault reset button or activating the binary input FaultResButton, all active
alarms change to confirmed state. Confirmed alarms will disappear from the Alarmlist as soon
as the respective condition dismisses. If the condition is dismissed before acknowledging the
alarm, the alarm will remain in the Alarmlist as Inactive. See also the Browsing alarms
chapter.
NOTE:
The input Sd Override can be used for temporary disabling of red alarms to shutdown the engine. This
input may be used in situations where providing the power is extremely important – e.g. if the gen-set
drives pumps for fire extinguishers (sprinklers).
6.14.2 Alarm states
An alarm can have following states: