Operation Manual

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The alarm system | AP70/AP80 Installation Manual
Magnetic variation missing
If heading source is set to be adjusted for magnetic variation, variation is taken from available
sensors in following order: Position source – Navigation source – Compass – any other
variation available on CAN bus. If variation disappears, last valid variation will be used until
automatic steering is cancelled and heading shown will then be corrected according to
alternative variation in the order given above.
Jump in heading data
If there is an abnormal heading jump in steering compass heading, an alarm (check heading)
will be given and a smooth transition to new heading will take place. There may also be a
compass difference alarm if a monitor compass is in use.
Speed sensor lost
If speed in use is lost there will be an alarm and smooth transition (2 min filter) to fallback
speed. Speed for steering and speed for navigation will use following use priority and fallback:
Steering: STW STW backup SOG SOG backup Manual speed Cursing speed
Navigation: SOG SOG backup STW STW backup Manual speed Cruising speed
Position data missing
During NoDrift steering, alarm is given and a smooth transition to position backup source
takes place. If no position backup steering source, steering mode will change to auto heading.
Navigation data missing
If lost during track/nav. steering, give alarm and change to auto heading steering.
Local supply voltage missing
When control unit(s) and CAN bus have different power source, alarm will be given on active
control unit with sound and flashing red power button led (display will go “black”). Main
steering computer will go to STBY mode and activate alarm on all other control units.
CAN bus supply voltage missing
Active control unit will give local alarm and rudder/thruster drive units will go to STBY mode.
Rudder/thruster drive computer failure
Alarm will be given and the ready signal to the steering /thruster gear will disappears. If sw
failure, there will be a watchdog restart of failing drive computer. The autopilot steering
computer will try to maintain steering as far as possible with remaining drive computers.
If the faulty unit is the autopilot steering computer, autopilot backup computer has to be
selected manually (ref. Menu- source selection).
List of possible alarms and corrective actions
The next pages includes a list of all alarms generated by the autopilot system.
The AP70/AP80 control units might also display alarms received from other units connected
to the system. Refer separate documentation for the relevant equipment for further
descriptions of these alarms.