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Protection
Alarms
2 - 24
SKF Multilog On-Line System IMx-M
User Manual
RLM: The relay activation process
1.
Alarm status information received
2.
Relays activated according to relays configuration and alarm status
3.
LED indicators updated
CMM: Storing of protection and relay events in the event log
1.
Alarm status or relay status received as events
2.
Event stored in event log
Alarm Trigger Filtering
Under certain conditions there could arise such a situation that the alarm status would
toggle rapidly between alarm and no alarm. The PRM provides two configurable means
to handle this,
hysteresis
and
enter
/
leave times
.
Configuration parameter
Leave time
is available for digital
channels only.
Important - Alert/danger ON trigger will be delayed by the configured
alert/danger enter time. Whereas alert/danger "Off" trigger will be delayed by the
configured alert/danger leave time.
Hysteresis
Hysteresis value is used to prevent rapid alarm state switching when the measurement
value is hovering around the configured alarm level but still changing enough to cross
the alarm level.
The hysteresis value is used to determine an adjusted value at which to leave the
alert/danger state. The hysteresis value would normally be large enough to encompass
the anticipated fluctuations/noise.