Simrad NSS12, Technical Manual

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Autopilot | NSS Installation Manual
¼ Note: You can switch the autopilot to standby mode and take manual control of the boat at
any time during the seatrial by pressing the ‘STBY/AUTO’ key.
The following seatrial calibration should be done:
•
Compass calibration; used to automatically compensate for on-board magnetic interference
•
Compass offset adjustment, used to compensate for a fixed offset in the final heading
readout
•
Wind vane offset to compensate for a wind vane that is not mounted facing in exactly the
same direction as the bow of the vessel (dead ahead)
•
Boat speed calibration
•
Transition HI/LO speed setting (the speed at which you want to change the set of steering
parameters)
•
Automatic tuning of the steering parameters
•
Setting the seastate filter
• ‘Saiboat Setup’ menu items
Compass calibration
Before the compass calibration is started, make sure that there is enough open water around
the vessel to make a full turn.
The calibration should be done in calm sea conditions and with minimal wind to obtain good
results. Follow the on-screen instruction, and use about 60-90 seconds to make a full circle.
During the calibration, the compass will measure the magnitude and direction of the local
magnetic field.
•
If the local magnetic field is stronger than the earth’s magnetic field (the local field is reading
more than 100%), the compass calibration will fail
•
If the local field is reading more than 30%, you should look for any interfering magnetic
objects and remove them, or you should move the compass to a different location. The
(local) field angle will guide you to the local interfering magnetic object.
¼ Note: Calibration must be made on the compass that is active for the autopilot. If the com-
pass is not possible to initiate calibration from the device list on the NSS, refer to the compass’
own instructions regarding calibration.
¼ Note: In certain areas and at high latitudes the local magnetic interference becomes more
significant and heading errors exceeding ±3° may have to be accepted.
Compass mounting offset
After compass calibration, the difference between the compass lubber line and the boat’s
center line should be compensated for.