NMEA issues

BruceB · 06 December 2009, 19:42

I seem to be having problems with the NMEA2000 network on my RIB that I am stumped with.
A few months ago I was coming back from Rum when one of my LMF400 gauges stopped working and went blank. I subsequently found the network cable to this gauge had worked loose and reinserted it and retightened at home.
All started working again however on my next trip I found certain parts of the network were dropping out and in as I went along and I have been unable to find out why.
I have, in order over the network, an LCX-27,Globalmap 5300i, LMF-200,LMF-400,LMF-400, LMF-400, LGC3000, Suzuki engine interface.
The bit I am confused by is when the network stops working it is only the LMF gauges and the Suzuki interface that are lost and they come back randomly. The plotters and the LGC-3000 GPS aerial never drop out.
Any ideas? its driving me nuts trying to figure out what is happening here!

Cookee · 07 December 2009, 09:26

Quote:

Originally Posted by BruceB

I seem to be having problems with the NMEA2000 network on my RIB that I am stumped with.
A few months ago I was coming back from Rum when one of my LMF400 gauges stopped working and went blank. I subsequently found the network cable to this gauge had worked loose and reinserted it and retightened at home.
All started working again however on my next trip I found certain parts of the network were dropping out and in as I went along and I have been unable to find out why.
I have, in order over the network, an LCX-27,Globalmap 5300i, LMF-200,LMF-400,LMF-400, LMF-400, LGC3000, Suzuki engine interface.
The bit I am confused by is when the network stops working it is only the LMF gauges and the Suzuki interface that are lost and they come back randomly. The plotters and the LGC-3000 GPS aerial never drop out.
Any ideas? its driving me nuts trying to figure out what is happening here!

I think you'll find they all need a common earth, so I would check that first.

Chris · 07 December 2009, 13:27

Where you have all the network "T's" joined together have you fixed them to a hard surface or are they all hanging loose in the console?

If they are not fixed to a solid surface or if they are only fixed at a couple of points then they can all flex causing loose connections and this will manifest itself in items failing intermittently. Each T has a hole in that you should use to fix it down. it is good practice that you should have a screw going through each T to ensure they don't flex.

It is worth putting vaseline into all the connectors as well before joinging them as corossion would cause similar problems.

Finally is the network terminated properly at each end with the terminator plugs that should have been supplied with the rigging kit.

BruceB · 07 December 2009, 17:04

The plugs are all secure and screwed to the inside of the console, dielectric grease was applied when put together earlier in the year and all go back to a common neg post.
What puzzles me is why the LGC3000 always is working as if it was a problem on the network you would expect this to drop as well, being between the gauges and the engine on the network cabling.
I am puzzled and perplexed

Chris · 07 December 2009, 18:36

How have you got the network set up?
Is it terminated at each end?
Do you have a seperate power supply to the network?
Where does the power for the Network come from?

I have attached a superb highly technical drawing I have done to demonstrate a couple of examples of what I am talking about.

BruceB · 07 December 2009, 19:50

The network is fed through a terminator feed and is set up like this-
The network worked fine for months and this is a new issue so the architecture is fine, there is a fault somewhere. The puzzling thing is that the GPS stays up in the middle of the failing compnents and they all come up and down at differing times, its not that all five dodgy parts start and stop working all at the same time!
If it was the whole one end of the network that wasn't working I could see the problem but it is the GPS aerial up all the time even when the gauges and motor have failed tha gets me.
The network is powered up all the time the isolator is on even when the ploters are off ecause my outboard warnings etc come via the network so I don't ever want them unavailable.

Chris · 07 December 2009, 20:56

Quote:

Originally Posted by BruceB

The network is fed through a terminator feed and is set up like this-
The network worked fine for months and this is a new issue so the architecture is fine, there is a fault somewhere. The puzzling thing is that the GPS stays up in the middle of the failing compnents and they all come up and down at differing times, its not that all five dodgy parts start and stop working all at the same time!
If it was the whole one end of the network that wasn't working I could see the problem but it is the GPS aerial up all the time even when the gauges and motor have failed tha gets me.
The network is powered up all the time the isolator is on even when the ploters are off ecause my outboard warnings etc come via the network so I don't ever want them unavailable.

Whats the wire coming out of the end of the left hand side is it one of those powered terminators?

If not, then where does the power get fed into the network?

Erin · 07 December 2009, 21:26

Is it worth swapping one of the LMF gauges with the GPS where it connects into the backbone to see if it still plays up.

Do the LMF's lose all power or do they just lose the data and flash at you. I had a failed EP-30 interface which resulted in the LMF showing no data.

BruceB · 07 December 2009, 23:49

There is no data from the outboard on any of the gauges or plotters. It isn't simply the outboard as the LMF's drop off the network in bus management.
The network is fed from an end terminator as shown.
When the gauges and outboard drop out they come back on the network randomly and then work for a little while before dropping back out.

Cookee · 08 December 2009, 09:20

I would disconnect things one at a time to see if there is a faulty gauge in the system disrupting the others?

9D280 · 08 December 2009, 11:25

I'm no expert on this, however putting my problem solving hat on, could you temporarily set your plotter to display some random engine functions that are shown on one of the gauges - then when the gauge drops out, you'll have an indication as to whether it's the source or not. Plotter will continue to tell you temp / rpm / whatever if it's a gauge / connectivity problem, but will presumably drop out as well if it's the source

The fact your plotter doesn't seem to give up makes me think there may be a problem with the engine data transmissions. (i.e your GPS reciever is working OK, as is the network)

Can you get any of your LM's to show lat / long? that would also prove / disprove the "plotter - Suz" link.

Chris · 08 December 2009, 21:30

Quote:

Originally Posted by BruceB

There is no data from the outboard on any of the gauges or plotters. It isn't simply the outboard as the LMF's drop off the network in bus management.
The network is fed from an end terminator as shown.
When the gauges and outboard drop out they come back on the network randomly and then work for a little while before dropping back out.

There are updates for all the guages on the Lowrance website. I installed the evinrude versions on my guages that used to be a bit flakey and they have been fine since.

You can dowload the updates onto your PC then unzip them onto an SD card. then you can install them via your lowrance LCX27 Head unit.

Would be worth ticking that off the list.

BruceB · 08 December 2009, 23:13

There are no updates available for LMF gauges that I can find..........

Chris · 09 December 2009, 09:40

Quote:

Originally Posted by BruceB

There are no updates available for LMF gauges that I can find..........

Are your guages specifically for Suzuki or are the generic. ie when you turn them on do they come up with a Suzuki logo?

Chris

BruceB · 09 December 2009, 16:40

My stuff, including gauges, is all Lowrance

jambo · 09 December 2009, 19:13

Hi Bruce, sorry to hear your having trouble. The guy Geoffs on here helped me last year with NMEA when I was thinking of doing it on mine. He maybe worth a PM.
Cheers for now hope you get it sorted.
Billy

BruceB · 09 December 2009, 19:38

Its only a niggle but its annoying that I cannot find it or the fault make sense to have some idea where to look.
I have bought a ethernet cable to link both plotters and when I am installing that this week I'll strip it all down and check the whole network and power system. Its an intermittent fault so probably a bad connection somewhere that I'll come across.......

Chris · 10 December 2009, 12:05

Quote:

Originally Posted by BruceB

Its only a niggle but its annoying that I cannot find it or the fault make sense to have some idea where to look.
I have bought a ethernet cable to link both plotters and when I am installing that this week I'll strip it all down and check the whole network and power system. Its an intermittent fault so probably a bad connection somewhere that I'll come across.......

Bruce I think you will need to go down a process of elimination with this start with just the engine, GPS aerial and one guage then once that is stable add in more T's and devices until the problem reoccurs. Then you may be able to nail it down to one particular T or device.

As for why you can have one device fail then another that is fine further down the network is quite possible when you look at how these networks operate.

geoffs · 06 January 2010, 21:28

Make a sketch of how you have it all connected,you should have a central backbone with a termination at each end and power fed in somewhere at one of the "t" joints. Then all your instruments and sensors come of one on each "t" only along the length. You should not have any doglegs or extra bits hanging on side arms. It is easy to get it right and easy to get it wrong, sometimes you get away with it and sometimes it plays up in weird ways. PM or thread if you need more assistance.

BruceB · 08 January 2010, 17:50

Hi Geoffs,
the network has worked perfectly for more than a year and only started playing up on a trip when I lost a single guage completely. When I got home I reconnected a network cable that had came loose and checked all the others for tightness.
I all came back up but every now and again it drops out again, all three guages lose the motor but the GPS stays up and this is on the network after the gauges and motor.
I have went round and rechecked and tightened every connection again but haven't been out much recently.
I should be out tomorrow and will see how it gets on.