Trim Potentiometers; Nmea Connections; Rudder Angle Transmitter; Pumpset - Nexus AUTOPILOT Installation And Operation Manual

INSTALLATION
9 INSTALLATION

9.5.6 Trim potentiometers

If a non-Nexus brand rudder angle indicator is fitted, it can be calibrated with the 2 trim
potentiometers as indicated on drawing. Adjust VR3 labelled offset, for rudder centre and
VR2 labelled gain, for maximum deflection.
Note! This is just to calibrate any non-Nexus rudder angle instrument. The Nexus
instruments must be calibrated by changing the rudder angle transmitter arm length.

9.5.7 NMEA connections

NMEA input from GPS Navigators etc. can be connected to Servo Unit terminals 12 (data)
and 13 (ground). For NMEA input, the overall shield should be terminated at the external
unit, and not at the Servo Unit.
NMEA output from Compass transducer can be taken from Servo Unit terminals 14 (data)
and 15 (ground). For NMEA output, the overall shield should be terminated at the Servo
Unit, and not at the external unit.

9.6 Rudder angle transmitter

The rudder angle transmitter should be mounted close to the rudder stock and driven by its
ball joint linkage according to the drawing shown below. The linkage should be linear, such
that 35 of rudder movement drives the arm 35 .
Small errors will not affect Autopilot operation but will cause inaccurate indication on the
rudder angle indicator. If possible, the linkage on the rudder transmitter should be adjusted
so that the digital rudder angle indicator on the Instrument display is consistent with the
rudder angle. The cable should be connected to Servo Unit terminals marked "RFU"
according to colours indicated.
The rudder transmitter unit must be securely mounted to a vertical surface and connected
by the adjusting tie rod linkage to the tiller, maintaining the geometry as detailed in the
diagram shown. The rudder transmitter arm must always swing in the same plane as the
tiller. Make sure all fasteners are well tightened and locked. For maximum watertight
integrity it is recommended that the unit is mounted with its rotary shaft facing downward.

9.7 Pumpset

For installation and specification, see separate manual.
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