Safety, Control and Monitoring System
Page 4 : 9
3.02
, Gas
0211 BC
The local monitoring system exchanges all its data
with the alarm management system trough a bus
connection (typically Modbus RTU RS485).
Local monitoring consists of:
• RPM meter located in the junction box on
engine, in the control room and on the bridge.
• Analog meter located in the junction box on the
engine showing oil pressure.
• Hour counter for engine running hours in the
Engine Control Cabinet.
• Local indication lights in the junction box on
the engine and on the control panel in the
Engine Control Room for Stop, Start, Reset and
Interlock as well as buttons for local operation.
Alarms and shutdown
General alarm handling
All alarms are to be handled by the ships central
alarm management system. All engine sensor data
is available at the alarm management system for
monitoring and alarm handling.
The alarm management system is to take proper
action if engine data exceeds given threshold levels.
All alarms not active during engine standstill are to
be disabled while the engine is not running.
Shutdown handling
All auto stops/shutdown situations are handled by
the Safety System. If such a situation should arise the
Safety System will close all gas supply, open for
ventilation of the gas supply line, turn off ignition,
close prechamber valve, activate the shutdown
solenoid (physically pushing rack to zero), signal
stop to the governor and give command generator
breaker out to propeller control. All shutdowns are
indicated on the alarm management system show-
ing which one that activated the alarm. All sensors
reading in data which directly can initiate a shut-
down have wire break detection. Actions done by
the safety system is based on activating relays to
physically break/close signal loop. All auto stops has
back-up functionality in the SSC System in case the
Safety System should fail. Signals connected to SSC
system does not have wire break detection.
The following situations will result in a shutdown of
the engine:
• Engine over speed - if engine speed goes above
given set point the engine will shutdown. This
alarm has triple protection as overspeed is also
monitored in the governor and ignition system.
• Low lubrication oil pressure - if the lubrication
oil pressure before engine is below given set
point the engine will shutdown.
This alarm indicates that bearings and vital
parts of the engine are not being proper lubri-
cated. Signal has wire break detection.
• Oil mist concentration high - if the concentra-
tion of oil mist in engine crankcase is above set
point - the oil mist detector will initiate a shut-
down. Signal has wire break detection.
• Emergency stop button - if the emergency stop
button on the engine, the ECC/Control Room or
on the bridge is activated the engine will shut-
down. Signals have wire break detection
Ignition failure - if the ignition system detects a
faulty behaviour, i.e. the engine is not firing, a
shutdown is activated.
• Gas Safety - activated if ships Gas Control
System detects a problem with the gas supply
(control problems or leakage). Signal has wire
break detection.
• Major alarm - alarm from the speed governor
indicating faulty behaviour. Activated if both
speed pickups fail, over speed, wire break on
the actuator signal or global misfire. Signal has
wire break detection.
For detailed information about set points, delay
time and interlock of the alarms, please see the
applicable alarm list.
Interlocks
The interlock situation is handled by the SSC system
and will block engine start
The following situations will result in an interlock
situation
• Low priming pressure - if the lubrication oil
priming pressure is below set point
• Control air pressure - If engine control air
pressure is below set point
• Starting air pressure - If the starting air pressure
is below set point.
• Key switch - if the key switch on the engine
control cabinet door is in the interlock position
• Auto stop - if there is an unacknowledged auto
stop present.
• Dwell time - start is interlocked for the first 5
minutes after stop. This situation is not active if
the stop is due to a start failure and the gas
valve has not been opened.
• Turning gear - If the turning is engaged.
• Start failure active - if there is an unacknowl-
edged start failure alarm present.
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