NMEA 2000 - Spawn of the money pit devil

[mlines]

Why does any NMEA 2000 installation always need a cable or adaptor that was not supplied in the box?

Why do NMEA 2000 parts cost so much?

Why is it possible to spend more on the cabling than on the device you are connecting?

Why are NMEA 2000 "Starter Kits" not called NMEA 2000 "Start to spend money kits"?

Sorry, just had to rant.

A failure of our lovely Standard Horizon has led us to "upgrade" to a SIMRAD Unit. A SIMRAD unit whose support line/email never answers and has also meant we have bitten an expensive bullet to connect in our other devices via NMEA 2000.

There, I feel better now.

 

[FullCircle]

Wait until the wind masthead unit fails after two years and a month.....

 

[DickieT]

Yes, agree, biggest rip off, even for boatie stuff. However the bits can be found to make your own cables. I was quoted something like £20 for a "NMEA" socket from marine suppliers. However the same plug from RS Components, stock no. 290 6534 only £5.41+ VAT. I had suitable five core cable and made up what I wanted for under £15. Off the shelf was a lot lot more. Cable in bulk for one off's not cheap but worth it if making multiple cables, especially if long. Also you can make them to exact size. The plugs/sockets are available in right angle versions as well. If you want to make a terminating version, which I did, there is ample room in the plug housing to fit 120 ohm resistors. It's a case of Practical Boat Owner, saving money, and making exactly what you want,
Good luck, Richard

 

[MountainGoat]

Actually a total convert to SeatalkNG. It's basically NMEA 2000, but more expensive.

 

[john_morris_uk]

NMEA 2000 doesn't have special plugs and sockets. You could twist the wires together and it would work.

Seatalk(ng) by Raymarine does. I was stung for £55 yesterday for a five way block and a short cable. The cable alone waz £25. Total rip off.

 

[ianj99]

Its rather like printers: low purchase price, money is in the consumables, with one big exception.

Third party consumable manufacturers cannot be stopped from supplying compatible ones.

No third party can manufacture cheaper cables because NMEA NMEA2000 etc are all trademarks and require membership of NMEA.org which is not free. Ditto Seatalk.

The position is exactly the same with Bluetooth. Its $8000 to have a new product listed even if its using an off the shelf pre qualified Bluetooth module. If you develop a product from scratch its $25000 which includes stringent compliance testing. (This is why wireless mice, keyboards etc which use Bluetooth never mention the fact.)

 

[superheat6k]

Yes, agree, biggest rip off, even for boatie stuff. However the bits can be found to make your own cables. I was quoted something like £20 for a "NMEA" socket from marine suppliers. However the same plug from RS Components, stock no. 290 6534 only £5.41+ VAT. I had suitable five core cable and made up what I wanted for under £15. Off the shelf was a lot lot more. Cable in bulk for one off's not cheap but worth it if making multiple cables, especially if long. Also you can make them to exact size. The plugs/sockets are available in right angle versions as well. If you want to make a terminating version, which I did, there is ample room in the plug housing to fit 120 ohm resistors. It's a case of Practical Boat Owner, saving money, and making exactly what you want,
Good luck, Richard

I am up for making my own NMEA 2K network.

Are these Hirschman plugs and sockets identical to those supplied on standard NMEA2K cables ?

Did you identify a source for the drop down Tee connectors ? I can't see these on RS.

 

[prv]

NMEA 2000 doesn't have special plugs and sockets. You could twist the wires together and it would work.

Huh?

NMEA 2000 absolutely does have special plugs and sockets. They come in two sizes called "Mini" and "Micro" (given the names I assume there's also some larger one that nobody uses):

Of course you could just twist the wires together and have it work, but that applies to pretty much any kind of electrical (perhaps not RF) cable. I could connect my desk lamp that way, but that doesn't mean that UK houses don't have standard plugs and sockets.

Unless you were planning to open up the cases and possibly get your soldering iron out, you would still need one plug for each device to access some bare wires.

Seatalk(ng) by Raymarine does. I was stung for £55 yesterday for a five way block and a short cable. The cable alone waz £25. Total rip off.

You should have just twisted the wires together, then

Pete

 

[DickieT]

I am up for making my own NMEA 2K network.

Are these Hirschman plugs and sockets identical to those supplied on standard NMEA2K cables ?

Did you identify a source for the drop down Tee connectors ? I can't see these on RS.

The Hirschman connectors are identical both physically and electrically to N2k connectors. The only difference I have noticed is in pictures of "genuine" N2k connectors the cable terminals are sometimes dotted with paint to indicate the core colours. But it's all pretty straightforward, plenty of web sites give all the information you need. These connectors from RS are also simply screw terminals for the cable, just the same as "N2k field connectors". Regarding T connectors, I have only seen them as accessories for N2k networks. However, I believe even if following the official protocol for N2k installation, terminal blocks (suitably protected) are accepted for T connections. So big savings there, no connectors at all ! My personal preference would be solder and adhesive heat shrink.
I have somewhere the RS stock number of suitable 4 core plus screen cable available in 25 m reels, unlike some sites where it is only available in 100m reels. I will have a look, but am away sailing at the moment.
Richard

 

[MountainGoat]

NMEA 2000 doesn't have special plugs and sockets. You could twist the wires together and it would work.

Seatalk(ng) by Raymarine does. I was stung for £55 yesterday for a five way block and a short cable. The cable alone waz £25. Total rip off.

You can twist SeatalkNG wires together and it would work as well. Indeed, that's basically how my SPX5 connects to my SNG network.

Where I am very grateful for SNG versus DeviceNet cabling, however, is how easy it was to thread a backbone cable through cable duct between my chart station and binnacle. No bulky retaining ring to snag on something half way into the run.

 

[john_morris_uk]

I thought NMEA2000 only referred to the electronic protocols, (baud rates, handshakes etc) not the connectors.

If they've sewn up the connectors that you HAVE to use as part of the protocol then my apologies and I've got it wrong.

 

[David2452]

I thought NMEA2000 only referred to the electronic protocols, (baud rates, handshakes etc) not the connectors.

If they've sewn up the connectors that you HAVE to use as part of the protocol then my apologies and I've got it wrong.

You haven't got it wrong at all, the N2K backbone and drop cable install protocol as per NMEA0400 standard even allows for using barrier strips instead of proprietary DeviceNet Tees, provided you can keep a 90% shielding and appropriate IP rating on the network you can do as you like. Obviously the cable needs to be to the correct spec but that is again simply factory process control DeviceNet cable. The equipment manufacturers leads and plugs are another thing entirely but have nothing to do with N2K protocols. One point, Garmin tend to be very good, even generous with the cabling and connectors supplied with their equipment, the best of all manufacturers on that score.