Shutdown System Overview - Volvo Penta D7A T Operator's Manual

SDU

Shutdown system overview

Shutdown unit (SDU)
The SDU has 6 shutdown channels and one over-
speed shutdown.
S1 Cooling water temp
S2 Lube oil pressure, Marine Gear
S3 Lube oil pressure, Engine
S4 Cooling water pressure
S5 Oil temp (optional D12)
S6 Exhaust temp (optional D12)
S1 - S5 has a ~1 second delay: S6 has no delay.
S1 - S6 are enabled or disabled accord. to eng. spec.
Shutdown reset
Activated shutdown must be reset before engine can
be restarted. Shutdown reset button on engine con-
nection box or MCU ACKN. button.
NOTE! Shutdown reset button will still show SD alarm
in MCU alarm list as not acknowledged alarm.
Acknowledge button on MCU panel will reset shut-
down and clear alarm list.
Broken wire
All channels are equipped with broken wire detection
that activate an alarm if connection is lost or power
supply to SDU is lost. Yellow LED indicates broken
wire. Reset alarm on Broken wire reset button (A).
NOTE! Use only plastic tool for reset.
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Overspeed shutdown
The overspeed function shuts down the engine in
case of overspeed.
Overspeed test
To test the overspeed function push the overspeed
test button (inside the SDU). When pushed the over-
speed limit drops 25%.
Emergency mode (shutdown override)
The system can be overridden by activating the OR
input (the Emergency mode lamp, when installed on
output SL, will be activated). Override does not inclu-
de overspeed.
Run detection
To avoid alarms when starting and stopping the engi-
ne an interlock for the shutdown pressure switches
(run detection) is implemented.