Raymarine Autohelm ST6000, Service Manual

Page: 97 / 214

Autohelm
Autohelm Autohelm
Autohelm
SeaTalk Service Manual 19
4. Common system problems
Problem Cause
Solutions
To be updated as necessary
“
“
“
“
5. Track control interfacing
In most cases interfacing the ST6000 to either a GPS, Decca, Loran or Satellite
Navigation system is a simple and straight forward task so long as the requirements
set out in section 6 of the installation manual are met. There are however a few
exceptions.
5.1 Inverted Data
Some receivers, notably some of the Furuno range and early Navstar models,
transmit data in an inverted format with respect to 5V. This is easily seen as the data
line will idle high with respect to 0V in between data transmissions. In these cases
the NMEA cable on the rear of the control unit must be wired with the red wire
connected to 5V (this is normally available on the receiver terminal block), and the
blue wire connected to the data line.
5.2 Conversion of Units.
All data containing units of distance will be converted to Nautical miles by the Control
Unit. Therefore any receivers displaying Cross Track Error or Distance To Waypoint
in either Kilometres of Statute miles etc will have their data displayed on the control
unit in Nautical miles.
5.3 Alarm Messages
Track mode has 3 alarm messages:-
1. No data
2. Data error
3. Large XTE If a standard NMEA sentence is not received by the ST6000
The ST6000 has recognised the incoming data as NMEA but has
detected an invalid flag. This is normally due to poor signal strength at
the receiver.
Cross track error greater than 0.3NM.
Errors 1 and 2 can provide valuable information as to where an installation problem
might lie. The 'No data' message indicates the ST6000 is not receiving NMEA data
and carries a high probability of a wiring error between the receiver and the pilot. The
'data error’