NMEA 2K query

[gjgm]

This is doing my head in!
I have a small backbone made up entirely of the T pieces. I have two plotters, power cable,transducer and another Garmin item. Both ends terminated with the plugs.
All works fine and both plotters see all items in the device list.
I now added a Vesper Marine AIS by adding another T piece, but neither plotter recognises it. I changed the cable-still not seen. I changed lots of cable over, and still nothing. I've tried changing the order on the backbone-still nothing. The unit has been sent back and tested and found to be working properly. So, I plug it back in, and still nothing seen.
The Garmin plotter takes 0183, so I can get AIS on that, but the Simrad only takes N2K, so I am unable to get AIS on that.
So, the cables seem fine, the unit seems fine, but what else do I try ?

 

[vas]

When you say doesn't recognise it, what do you mean? Not listed in the NMEA2K devices on EITHER plotter, or not utilised to show targets on the plotter screen?

If the former and from experience (without having used the Vesper),
try to minimise the backbone. So try to create a v.small net with just the Vesper and the one plotter (try the garmin first I say) If it works, start building up adding the other device. If it still works add the Simrad and then the next etc...
Assuming Vesper and Garmin don't work, try Vesper and Simrad alone. Generally, start small make sure one sees another and start adding until you find the offending item. BTW, what is the other garmin item?
Also try updating firmware on your h/w.

if the latter, must be software issues and nicely hidden menus to work with?
If s/w email garmin support, they are a v.helpful bunch MarineSupport.Europe@garmin.com

cheers

V.

 

[jfm]

Hmm.

I'm reading your post as saying the plotters can't see the AIS on the device list, which means your problem is a network problem and nothing to do with display menu settings on the plotter.

I've done a lot of N2k and I think the experiments you have done are all v sensible. So I'm baffled too and have no idea what is wrong. Would be good to swap kit with another N2k boat (I would happily do that with my boat, but I'm in SofF)

 

[lpdsn]

I had a baffling N2K problem last year, which when I eventually found the cause with a bit of guidance from Raymarine was due to one unit backing off when it saw the same PGN being transmitted by something else.

So I'd endorse the approach suggested by Vas of going to a minimal network then if you get it working slowly build things up till it stops working.

I've a ShipModul Miniplex which was very good at identifying which PGNs were on the network, albeit you have to decode it from Hex - getting the PGN number is about my limit at that.

 

[gjgm]

Thanks..so I started with the power input, the the garmin plotter and built up. At no time was the AIS in either plotter device list..everything else is, and works.
Well, I'll buy one more cable and try that from the AIS to the backbone..it would explain if that was faulty, but I have tried changing these before...you never know ! I'll see if there is a firmware upgrade for either plotter, though I think they are pretty up to date. The AIS is certainly with the latest!
Thanks all..at least 0183 works !

 

[lpdsn]

If you can borrow something that will allow you to get info on the messages coming out this is a summary of the PGNs in N2K. Obviously doesn't describe the bits and bytes of the message but you hopefully will be able to find which PGNs are present.

https://www.nmea.org/Assets/20151026 nmea 2000 pgn_website_description_list.pdf

The NMEA0183 VDM sentence corresponds to a number of N2K PGNs, e.g. 129038. If you can show these are present than you have an idea the AIS is working properly and can suspect the plotter.

A suitable ShipModul Miniplex will give the the Hex of the messages. I believe Maretron also have an all-singing, all-dancing box that will give you the data in N2K messages, but it isn't cheap.

 

[gjgm]

If you can borrow something that will allow you to get info on the messages coming out this is a summary of the PGNs in N2K. Obviously doesn't describe the bits and bytes of the message but you hopefully will be able to find which PGNs are present.

https://www.nmea.org/Assets/20151026 nmea 2000 pgn_website_description_list.pdf

The NMEA0183 VDM sentence corresponds to a number of N2K PGNs, e.g. 129038. If you can show these are present than you have an idea the AIS is working properly and can suspect the plotter.

A suitable ShipModul Miniplex will give the the Hex of the messages. I believe Maretron also have an all-singing, all-dancing box that will give you the data in N2K messages, but it isn't cheap.

I should say that the Vesper UK dealer has spent quite some time with me over email..well, alot of time ! and the unit was sent to NZ and back for analysis, free of charge, so I can't fault their support. I therefore don't think it is the unit itself...but with a network of one plotter and one power input and the AIS..and it STILL doesnt work....Now I think about it..when I first installed the Simrad, it did find it...and showed the AIS targets...Maybe that new cable is indeed suspect...seems the next place to try.
Now then..trim tabs...? No, I think having replaced everything I must almost be there!
Anyone got an old halogen cantalupi fitting ?!

 

[mlines]

I see you are listed as being on the solent. If you wanted to plug it into a N2K network with currently working AIS (via Actisense converter) and a Simrad plotter and N2K power then we could try it on my boat (Universal marina, hamble)

 

[gjgm]

MLines..that's very kind..we moved to Poole last week! Doubtless we will be in the Solent some time, so perhaps if it still isn't sorted I can get in touch.
I'd better change my location....