NMEA 2000 101

[rumham]

not sure how far you want to go or what your technical level is, but have you heard of OpenSkipper | Display and process NMEA 0183, NMEA 2000 & AIS data from nautical instuments or similar? you can do pretty amazing things with a £3 esp32 microcontroller these days

 

[Hoolie]

Raymarine are happy to provide the facility to daisy-chain though a number of their devices..

Used to with SeatalkNG, but discontinued on later devices that are now fully N2K compliant .

 

[st599]

Doesn't N2000 just follow the low speed CANbus spec? (I was going to check, but £1500 for the spec is a bit much)

 

[PaulRainbow]

Indeed... just like (from memory) the NMEA2000 spec. states that devices cannot be daisy-chained..

Raymarine are happy to provide the facility to daisy-chain though a number of their devices..

You end up with more than one device sharing a drop cable..



Edit: Although I now seem to recall that that requirement was something to do with a failure of electronics within one device should not be able to affect the connectivity of another device within the system.

The N2K standard does not preclude having multiple devices sharing a drop cable.

 

[PaulRainbow]

Used to with SeatalkNG, but discontinued on later devices that are now fully N2K compliant .

Still does, lots of STNG stuff still available.

 

[PaulRainbow]

Doesn't N2000 just follow the low speed CANbus spec? (I was going to check, but £1500 for the spec is a bit much)

Yes, N2K is based on the Canbus protocols.

 

[Gixer]

Just to bring this thread back to my level. Why does one power cable have two wires and another has five??

 

[PaulRainbow]

The second cable is probably a cheap Ali Express type cable, where they have not bothered to cut the redundant wires off. You can see on the first cable where the end has been heat shrinked, that's to cover the wires that were cut off.

 

[Gixer]

Ahh, it's a simple as that. Thanks again Paul.

 

[Martin_J]

The lower cable has also used a strange colour for the fused +12v.

The white is usually one of the data pair (along with the blue).