14
SETTING THE COMPASS COMPENSATION VALUES
It is important to decide before setting the compass compensation how the
alignment of the vessel is to be achieved. If a hand bearing reference compass
is to be used, set the unit to display Magnetic. If maps or chart references are
to be used, set the unit to display True, and ensure that the magnetic variation
is correctly set (see above). It is important that the correct magnetic variation is
set before doing the compass setting, because the magnetic variation is
always allowed for before the true heading is displayed.
Compass errors can be compensated as follows:
1.
2.
3.
4.
5.
Put the unit into the Engineering mode as described in SELECTING
ENGINEERING MODE above. Then put the unit into compensation mode by
pressing UP and DOWN together. The first display is 45°, representing
North-East. Bring the vessel to 45° bearing and wait at least 10 seconds for
the sensor value to settle. Press ENTER to log the bearing. “At” is displayed
to indicate that the value is logged.
Press INC again to move the indicated bearing to the next bearing, and
repeat the process at each 45° step until the 315° bearing has been logged.
When all the errors have been logged, press UP and DOWN together to
return to Engineering mode.
To exit Engineering press ENTER
As a final test, the vessel can be swung to confirm that the compass is
operating satisfactorily with all errors correctly compensated.
These errors can be compensated automatically in the Target/Cruiser Compass
if the vessel can be pointed accurately in particular directions by reference to
known geographical features. Compensation is done by logging the actual
readings when the vessel is correctly aligned at the principal directions 45°
(North-East), 90° (East), 135° (South-East), and so on. The logging is done
automatically, with the compensations calculated and permanently stored in
the unit’s memory. In normal operation of the compass, corrections at
intermediate angles are in proportion to the compensation values logged at the
eight principal directions.
CLEARING THE COMPASS COMPENSATION VALUES
If it is desired to return all the compensation values to the factory defaults, put
the unit into the Engineering mode as described in SELECTING ENGINEERING
MODE above. Press ENTER, UP, and DOWN together (this three-key
requirement is to ensure that the clear is not done by accident). The word “clr”
is displayed for two seconds to indicate that all the factory compensation
settings have been restored.