SeaTalkNG vs NMEA2000

[Quickstep192]

I’ve got a mix of electronics. My Raymarine AutoPilot uses SeaTalkNG to communicate between the controller and the display, but the autopilot is not integrated with the Raymarine ChartPlotter (although the ChartPlotter is SeaTalkNG capable. The TackTick instruments get info from the ChartPlotter using an NMEA0183 connection. The VHF radio is NMEA2000 capable.

It seem like I could get everything on SeaTalkNG by buying a couple of extra SeaTalkNG hubs, some cables and a wireless gateway for the TackTick, but before I run out and buy that, I’m wondering if I should be considering building and NMEA2000 network instead so I’m not tied to Raymarine when it comes time to replace components down the road.

Would NMEA2000 be more flexible and still let me integrate my current components?

 

[GMiller]

NG is N2K. Just proprietary fittings. Plenty of adaptors available for micro c to ng.

 

[caius]

Yep, it’s electrically the same, except the Raymarine backbone also carries a seatalk1 conductor - that is independent of the NMEA2000 data though and is only present for convenience if you have older instruments to connect to it. You can in theory mix and match instruments from different manufacturers, however there might be limitations on proprietary features like calibration of sensors.

Connecting the autopilot to the chart plotter will allow you to control it form the plotter screen, and also allows steering to waypoints on the route you are following.

If most of your kit is Raymarine, it would probably make sense to use their backbone stuff. You can get adapter cables if you need to connect 3rd party devices.

 

[Quickstep192]

Thanks for that info. Since I already have a small SeaTalkNG network on board and since running new wire is such a pain in the ass, it seems like it might make sense to just expand on what’s there.

The TackTick instruments are already connected to the ChartPlotter by an NMEA0183 connection. If I’m putting the ChartPlotter on SeaTalkNG do I need to get the TackTick onto the SeaTalkNG network or can the NMEA0183 from the TackTick peacefully co-exist with the SeaTalk connections?

 

[caius]

I'd say that depends on what data handling your plotter can do. You don't say which one it is, but often you can configure where data is repeated in the settings somewhere. In that case it might be able to repeat the NMEA 0183 data onto the SatalkNG bus which means the autopilot would also be able to see it without having to use an adapter to connect the TackTick instruments to SeatalkNG. That can be useful for things like steering to the wind vane, and modern autopilots like as much data as you can feed them.

If the plotter won't do that, then there's various adapters available to convert NMEA0183 to NMEA2000 to do it instead. It wouldn't affect the plotter as that would get the data either way. You might not want the extra expense of doing it that way if you can live without the autopilot seeing the TackTick data.

So yes, either way they will co-exist peacefully but there might be an advantage to doing it one way or the other depending on the specifics of your network.

 

[Quickstep192]

I’m still exploring, but I believe the TackTick is getting Heading and SOG via NMEA from the GPS, but the C90W ChartPlotter doesn’t benefit from any data coming across the NMEA from the TackTick because the C90W ChartPlotter isn’t capable of displaying any instrument data.

Can I keep the NMEA connection between the ChartPlotter and the TackTick and also connect the ChartPlotter to the SeaTalkNG bus so the ChartPlotter can trade data with the autopilot and get AIS data from the VHF? Or, is it necessary to pick either NMEA or SeaTalkNG, but not both?

 

[caius]

but the C90W ChartPlotter doesn’t benefit from any data coming across the NMEA from the TackTick because the C90W ChartPlotter isn’t capable of displaying any instrument data.

It should be able to - have a look in the manual chapter 14 titled 'Using the data application'.

The data contained in each data panel. This data can include any transducer or internally calculated navigation data that is available on NMEA or SeaTalk. Additional data includes a compass rose, a distance log, and four resettable trip counters.

I don't know if there is also the capability to add data fields or overlays to the chart app - it is apparently possible to customise the data bar display but I don't know to what extent or what data options you have. The axiom plotter I use can display pretty much anything it has access to, but that's obviously a newer software version.

Can I keep the NMEA connection between the ChartPlotter and the TackTick and also connect the ChartPlotter to the SeaTalkNG bus so the ChartPlotter can trade data with the autopilot and get AIS data from the VHF?

Yes. It will work with both connected at the same time. If your VHF is NMEA2000 it should also output VHF DSC messages, which will show up on the plotter as well as AIS data - eg a distress call will show an alert and location on the chart. You have to enable this in the settings however.

I can't see any reference in the manual to transferring data between SeatalkNG and NMEA0183 and vice versa, so I don't know whether that's possible, but having them both connected at the same time shouldn't be a problem.

I would suggest that if there's anything specific like that you need to know then Raymarine's tech support people are usually quite good. They unfortunately closed their old forum, which was a great resource, but you can ask questions via their website and they will put you in touch with someone who can answer the question if it's not immediately available.