Seiwa SW AP03 - Manual (Page 23)

This is one of two options to reduce deviations caused by
magnetic components and material on the vessel. To carry out
this calibration, press the right arrow. The display reads:
AUTO CALIBRATE
TURN 360 DEG
PROGRESS 000
With the vessel under way and steering it by hand, turn it slowly through a
full circle. You may turn either to port or starboard, but the same
direction should be maintained until the circle is complete. The
progress display shows the angle turned through so far. When the
circle is complete, the display shows the calibration results, eg.
MAG FIELD MEDIUM
PERMAG ERROR LOW
CALIB REPORT
SOFT ERROR MEDIUM
Line 2 rates the overall strength of the earth’s field at the compass
as low, medium or high. A high reading should be seen at the
equator and medium or low from 20 degrees or more away from the
equator. Line 3 rates the level of error produced by magnetised
material in the vessel and Line 4 rates the error produced by
concentrations of soft iron in the vessel. The results are for
guidance only as there are interactions between the three ratings.
Sec 3.3 gives more information on optimising compass
performance.
Press STANDBY to return to normal operation. This method of calibration is
simple and is a recommended procedure for all vessels. However
there are some magnetic anomalies which are not fully removed.
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The manual calibration option provides a further refinement of compass accuracy.
21
COMPASS
CALIBRATION
AUTO