AUTOPILOT
rudder is moved as necessary to return the boat back on course. The sensitivity to
course errors andamount of correction are user adjustable to suit different boats under
various sea conditions.
NB * (PID control, terminology as known by control technicians,
P = proportional part, I = integral part and D = derived part)
Factory default settings and automatic calibration, establish a basis for normal steering
and may be further fine tuned if necessary. During set up routines, the compass is
automatically compensated and installation errors such as reversed rudder feedback
and reversed pumpset wiring or piping are automatically diagnosed and corrected.
During this routine also the rudder speed is automatically optimised. This greatly
reduces installation set up and sea trials time while eliminating possible Autopilot
malfunction.
1.4 Components
1.4.1 Autopilot instrument
Control and display of all Autopilot functions are provided by the Autopilot instrument. It
is waterproof and may be mounted below or above deck. Multiple Autopilot instruments
can be connected and the Autopilot may be activated by pressing the push-buttons of
any instrument.
1.4.2 Servo Unit (A-1500 and A-1510)
The Servo Unit contains the course computer and pumpset motor drive circuitry and
acts as a centre for interconnecting wiring. It is splash proof and should be located
centrally to minimise lengths of wiring. The powerful microprocessor in the Servo Unit
accepts heading information direct from an electronic compass or gyro compass (A-
1500 only), wind transducer, navigators and compares this against the course set by
the instrument and rudder.
1.4.3 Rudder Angle Transmitter
The Rudder Angle Transmitter provides the Autopilot with accurate rudder position
information. It is mounted near the rudder shaft and connected to the tiller arm or
quadrant with an adjustable ball joint linkage.
1.1.1 Compass transducer
No Autopilot can steer better than the compass stability will allow. The Nexus compass
excels in this characteristic, where the liquid dampening provides for stability even at
high speeds in heavy seas. The high gimbaling angle, eliminates compass disturbance
with boat heeling or rolling. The compass provides a stable heading reference for the
Autopilot and should be bulkhead mounted below deck near the centre of pitch and roll
for maximum stability. Construction is splash proof. The Autopilot Servo Unit or the
Nexus Server can re-transmit the compass heading on the NMEA output port to
receivers such as radars, plotters, compass repeaters etc.
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