STOWE MARINE DATALINE-X COMPASS, User Manual

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Part 4 Setting-Up
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11. If possible check the compass against known compass points. If a
constant heading error is found then consult your dealer.
4.8.2 Compass Auto-Deviation Compensation - With the Robertson
RFC250 Heading Sensor
The RFC250 Heading sensor is calibrated automatically by performing at least
two sequential 360° turns within five minutes of system turn on. This is best
performed in good conditions, with a calm sea.
1. Place the vessel in a position able to swing through a full 360°.
2. Align the vessel to approximately 270 degrees. It must not be at a
heading of below 180 degrees.
3. Turn the compass system on, If it was already turned on then turn it
off, wait a few seconds, and then turn it back on again.
4. Begin swinging the vessel, either by hand or by motoring circles.
The rate of rotation is not critical, but about one minute per
revolution is suitable. The movement should be smooth, with a
minimum of roll and acceleration. The process will be completed
when the vessel has swung three times through North.
5. If possible check the compass against known compass points. If a
slight constant heading error is found then the heading sensor can
be turned to correct this. The sensor should then be checked again.
Notes:
1. Some versions of the RFC250 Heading sensor output the NMEA
message that gives the Compass Calibration Status to the
COMPASS display.
2. The displays given by these sensors will be as below:
'HdG' = The Auto Deviation Compensation process has not
been performed since the last power up.
'HdGc' = The Auto Deviation Compensation process is complete,
the heading sensor is Compensated.
3. In this case if Calibration is to be done the boat should be swung
within five minutes of power up until the display shows ‘HdGc’.
‘HdGc’ will then be shown until the next time that the sensor is
powered down.
4. RFC250 Heading sensors which do not have this feature will always
show ‘HdG‘, even when the Calibration process has been successfully
completed.