Owners manual

26
The vessel's speed is read from the RMA or RMC data sentence or one of the
following:
VBW
Vessel Speed relative to water from Dual
Doppler Speed Log.
VHW
Vessel Heading and Water Speed
VTG
Vessel Track and Ground Speed
CROSS TRACK ERROR RESPONSE
The response of the autopilot is set with
the master select switch in the
NAV
position.
Press the
TURN
key, and then the green
ARROW
key to select normal
indicated
by an 'n' on the right of the display
, or
reversed
indicated by an 'r' on the right of
the display
response to cross track error.
If the setting is incorrect, the vessel will
initially turn to the correct heading, but
then as some cross track error develops,
the vessel will continually turn further and
further away from the correct heading to
the waypoint.
Cross Track Error contains two pieces of
information; the amount of the error, and
the 'sense' of the error (i.e. whether the
vessel is to the Left or the Right of the
line between the beginning and ending
waypoints).
The NMEA
National Marine Electronics
Association
has specified how the cross
track error should be identified (i.e. a
(L)eft indicator in the data sentence
means the vessel should steer to the left
and a (R)ight indicator meaning the
opposite).
However, some manufacturers have
used the (L)eft indicator to mean that the
vessel is to the left of the line, which
means the vessel should steer to the
right, and the (R)ight indicator to mean
the opposite.
Because of this confusion, the response
of the autopilot to cross track error can
be switched from 'Normal', meaning the
vessel will respond normally to the sense
of the cross track error, to 'Reversed',
meaning the vessel will respond the
opposite way in response to the same
information.