The new boat is coming with Raymarine ST70 instruments and an SPX autopilot.
I'll be adding a chartplotter (probably a Garmin 4 or 5000) and a laptop. I'll need to organise the interface amongst all this stuff.
The Ray SPX autopilot has a set of NMEA out terminals. Will this NMEA out contain the data that the Autopilot receives on SeaTalkNG from the ST70's?
Alternatively, Is there a commercially available SeaTalkNG to NMEA converter?
I believe that I can extract 'old' SeaTalk from SeaTalkNG using a Raymarine adapter cable.
If I can extract the SeaTalkNG data from the ST70 instruments (in NMEA or 'old' Seatalk form then I can send that to a multiplexer from which I can drive the plotter and laptop. The multiplexer would also have inputs from an AIS receiver and a DSC radio.
Other than buying a Raymarine plotter instead, is there a better way to do
this?
The other concern is data duplication: Does the SPX computer prioritise it's inputs, so that it gives preference to SeaTalkNG input or one of the other inputs, or is it just a case of first come first used?
I don't have an answer.
I would recommend you open an inquiry to Raymarine (ask raymarine option under support) and ask specifically what sentences the SPX outputs on it's NMEA-0183 port(s).
I have found that the E-series chartplotter makes an excellent bridge between NMEA-2000 and NMEA-0183