Re: AIS / Autopilot Conflict

Herbert Lackner

Hi Rink and Woody,

why do I recommend to search the problem at the AIS connection side?

1.) I am an electrical engineer and raymarine dealer and would confirm that  Woodys RM installation-plan is ok. No extra power is needed.
2.) Woody confirmed that the problem with the STNG bus starts as soon as he connects the AIS STNG connection to the bus, even if the AIS has no power connection and is powered off.  That is a very clear indicator where the problem is.
3.) without the AIS the STNG bus works fine according to Woody (Autopilot working, connection to wind and speed (so the ITC5 is working)), the complete RM network works fine
4.) cable length of the STNG backbone should be no problem on the SM (this could easily be checked by connecting the AIS STNG cable to the bus at one of the free sockets where the Instruments are plugged in, I assume the problem still persists)

this leads direct to a problem with the AIS STNG bus connection, either with the cable (internal short) or with the interface unit. 
And in addition: I had exactly the same problem on KALI MERA last year with a very similar setup. The RM network is similar to Woodies, I have more plotters and more devices, but no additional power source. And I had the RM650 AIS installed. Everything worked fine for years and then - after some time away from the boat - The RM network did not work anymore. Took me a some hours to find out that the reason was the AIS STNG connection.  Exactly the same behaviour as Woodies installation.  I tried to repair it but found out that it has to be sent to the UK Raymarine Repair center (what I did not do). Lightning seems to be the reason for the damage.

Quickfix was to connect the AIS to one of the plotters using the NMEA0183 interface (not the NMEA2000 what is SeatalkNG, STNG), that worked fine and therefore I kept the RM650 as a backup AIS device and plugged in a new RM700 AIS device that worked without any problems.  For me - with all that infomation I got - pobability is very high that Woodys Problem is very similar and the solution could be the same.

Of course there could be other reasons, as always, and - as we say in Austria "the devil does not sleep".  As someone who ist very familiar with the RM equipment I can say that the stuff works "plug and play" and would recommend adding additional power only by experts. 
Of course there is still the chance that the problem is not at the AIS side, but if so it will work if you plug it in another socket near to the course computer, that is something that could be tried. Defect cable would be the cheapest fix...

Hope that this messaqe can help, I know how frustrating this kind of troubleshooting can be 

fair winds, herbert


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