Garmin GHP 20 Marine Autopilot System for Steer-by-Wire, Installation Instructions Manual

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Performing the Autotune Procedure
Before you begin this procedure, you must have a large stretch
of open water available.
1
Adjust the throttle so the boat travels at a typical cruising
speed that provides responsive steering.
2
Select an option:
• If you are performing this procedure as part of the Sea
Trial Wizard, select Begin , and continue to drive in a
straight line.
• If you are performing this calibration outside of the Sea
Trial Wizard, from the heading screen, select Menu >
Setup > Dealer Autopilot Configuration > Automated
Setup > Autotune > Begin .
The boat performs a number of zigzag motions while the
autotune is in progress.
When complete, a message is shown.
3
Select an option:
• If the autotune completes successfully, select
Done and
take manual control of the boat.
• If the autotune fails, increase the throttle, select Retry ,
and allow the system to perform the autotune again.
4
Select an option:
• If the autotune fails, but you have not reached maximum
cruising speed, repeat steps 1–3 until the autotune
completes successfully.
• If the autotune fails and you have reached maximum
cruising speed, reduce your speed to the initial autotune
speed and select Alternate Autotune to begin an
alternate autotune procedure.
Setting North
Before you begin this procedure, you must have a large stretch
of open water available.
This procedure appears if the autopilot is connected to an
optional GPS device ( page 13 ), and the device has acquired a
GPS position. During this procedure, the autopilot uses the GPS
heading information to calibrate north on the autopilot system.
If you do not have a GPS device connected, you are prompted
instead to set the fine heading adjustment ( page 16 ).
1
Drive your boat at cruising speed in a straight line.
2
Select an option:
• If you are performing this procedure as part of the Sea
Trial Wizard, select Begin , and continue to drive in a
straight line.
• If you are performing this calibration outside of the Sea
Trial Wizard, from the heading screen, select Menu >
Setup > Dealer Autopilot Configuration > Automated
Setup > Set North > Begin .
3
Allow the autopilot to calibrate north.
When the calibration is complete, a message is shown.
4
Select an option:
• If the calibration completes successfully, select
Done .
• If the calibration fails, repeat steps 1–3.
Setting the Fine Heading Adjustment
This procedure appears only if you do not have an optional GPS
device connected to the autopilot ( page 13 ). If the autopilot is
connected to a GPS device that has acquired a GPS position,
you are prompted to set north instead ( page 16 ).
1
Using a handheld compass, identify north.
2 Select an option:
• If you are performing this procedure as part of the Sea
Trial Wizard, adjust the fine heading setting until it
matches north on the magnetic compass.
• If you are performing this calibration outside of the Sea
Trial Wizard, from the heading screen, select Menu >
Setup > Dealer Autopilot Configuration > Automated
Setup > Fine Heading Adjustment , and adjust the fine
heading setting until it matches north on the magnetic
compass.
3
After the fine heading setting matches north on the magnetic
compass, select Done .
Testing and Adjusting the Configuration
NOTICE
Test the autopilot at a slow speed. After the autopilot has been
tested and adjusted at a slow speed, test it at a higher speed to
simulate normal operating conditions.
1
Drive the boat in one direction with the autopilot engaged
(heading hold).
The boat may oscillate slightly, but it should not oscillate
significantly.
2
Turn the boat in one direction using the autopilot and
observe the behavior.
The boat should turn smoothly, not too quickly or too slowly.
When you turn the boat using the autopilot, the boat should
approach and settle on the desired heading with minimal
overshoot and oscillation.
3
Select an option:
• If the boat turns too quickly or too sluggishly, adjust the
autopilot acceleration limiter ( page 16 ).
• If the heading hold oscillates significantly or the boat does
not correct when turning, adjust the autopilot gain
( page 16 ).
• If the boat turns smoothly, the heading hold oscillates only
slightly or not at all, and the boat adjusts the heading
correctly, the configuration is correct, and no further
adjustments are necessary.
Adjusting the Acceleration Limiter Settings
1
Enable Dealer Mode ( page 17 ).
2
Select Menu > Setup > Dealer Autopilot Configuration >
Autopilot Tuning > Acceleration Limiter .
3
Select an option:
• Increase the setting if the autopilot turns too quickly.
• Decrease the setting if the autopilot turns too slowly.
When you manually adjust the acceleration limiter, make
relatively small adjustments. Test the change before making
additional adjustments.
4
Test the autopilot configuration.
5
Repeat steps 3–4 until the autopilot performance is
satisfactory.
Adjusting the Autopilot Gain Settings
1 Enable Dealer Mode ( page 17 ).
2 Select Menu > Setup > Dealer Autopilot Configuration >
Autopilot Tuning > Rudder Gains .
3
Select an option based on the type of boat:
• If you have a sailboat, select
Gain and adjust how tightly
the rudder holds the heading and makes turns.
If you set this value too high, the autopilot may be
overactive, attempting to constantly adjust the heading at
the slightest deviation. An overactive autopilot can drain
the battery at a faster-than-normal rate.
• If you have a sailboat, select Counter Gain and adjust
how tightly the rudder corrects the turn overshoot.
If you set this value too high, the autopilot can overshoot
the turn again when attempting to counter the original
turn.
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