Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 12-07-2018, 10:26   #16
Registered User
 
Suijin's Avatar

Join Date: Feb 2013
Location: Annapolis MD; currently in Oriental NC
Boat: Valiant 40
Posts: 3,530
Re: Troubleshooting NMEA 2000 and the troubles with NMEA 200

Well I did something else. The network faulted and refused to transmit data despite cycling it half a dozen times; I removed a cluster of T’/drops (plotter, GPS, rudder); the network booted fine; put the T’s back in and network booted fine and has been fine for a couple of hours.

This is part of its intermittent behavior. The connections were tight before taking them apart, so nothing changed. But we’ll see.
__________________

Suijin is offline   Reply With Quote
Old 12-07-2018, 10:51   #17
Registered User
 
transmitterdan's Avatar

Join Date: Oct 2011
Boat: Valiant 42
Posts: 4,366
Troubleshooting NMEA 2000 and the troubles with NMEA 200

I suspect the power draw from the devices exceeds the ratings. Have you done the calculations of all loads to verify that the system is not power starved? This is quite common.
__________________

transmitterdan is offline   Reply With Quote
Old 12-07-2018, 10:57   #18
Senior Cruiser

Cruisers Forum Supporter

Join Date: Jul 2005
Location: Bellingham
Boat: Outbound 44
Posts: 5,444
Re: Troubleshooting NMEA 2000 and the troubles with NMEA 200

Are you confident that you have both ends of the backbone terminated properly?
What brand of mfd display do you have? Some have a nmea 2000 diagnostic page that shows the number and type of transmission errors while running.
__________________
Paul
Paul L is offline   Reply With Quote
Old 12-07-2018, 13:48   #19
Registered User
 
CarinaPDX's Avatar

Join Date: Jan 2010
Location: Portland, Oregon, USA
Boat: 31' Cape George Cutter
Posts: 1,821
Re: Troubleshooting NMEA 2000 and the troubles with NMEA 200

It seems odd to me that you are powering 2 mfds off the network. You need to start getting quantitative about this: add up all of the loads on the network and see if they are within spec for the micro- or mini- cable that you are using for the backbone. Is the power being inserted in the middle with a power tap of the right rating? Of course this should have been done before installation; if so, then try some measurements.

I would use a spare t-tap and check voltage at various locations in the network. N2K cables have 5 conductors: 12VDC power (+/-), data (+/-) and shield. The terminating (pull-up) resistors at each end connect the 12VDC+ to the data+, while the various devices pull the data+ down to signal. The 12VDC+ line at the resistors would be a good place to check for power adequacy, as it would include the voltage drop through the length of the backbone. It would be more difficult to test the signal line, probably with a scope, so let's hope that is never necessary.

If we are just guessing, I would guess that the problem is a power one, either due to too much load, inadequate source or cabling, or a contact that is too resistive. The thermal sensitivity hints at a resistive (dirty, loose, or corroded) contact but if so, it may just be the last straw in a marginal setup.

Good luck,

Greg
CarinaPDX is offline   Reply With Quote
Old 12-07-2018, 14:47   #20
Registered User
 
Reefmagnet's Avatar

Join Date: May 2008
Location: puɐןsuǝǝnb 'ʎɐʞɔɐɯ
Boat: Nantucket Island 33
Posts: 2,691
Re: Troubleshooting NMEA 2000 and the troubles with NMEA 200

Quote:
Originally Posted by Suijin View Post
OK I'm now suspecting the masthead connection. The stick was down for a year with the simnet cable dangling exposed. I did not clean the female sockets before reconnecting in the rush to get everything ready to step the mast.

Would result in bad termination, which i think would explain everything getting power on the network but the plotter and mfd's not seeing any data from other sensors/devices. Yes?

Up the mast I go. Any advice on cleaning the sockets for the pins? They be tiny....

And thanks everyone for the input and advice. I appreciate it very much.

I have a mixed network comprised mostly of Simnet (which I think is just about all but obsolete now) and NMEA 2000 (and NMEA 0183, too!). I vaguely recall that although Simnet allows daisy chaining of devices (akin to having multiple devices attached to a single NMEA 2000 drop) it only works for some devices and some care is required in connecting everything to ensure that the same "backbone and dropper" structure of a standard NMEA 2000 network is maintained.



For cleaning the Simnet connector at the masthead, I'd suggest not using any abrasives, but just giving the connection a good flush out with contact cleaner. Apply silicon grease to the plug and socket before reconnecting to protect against moisture and corrosion.
Reefmagnet is online now   Reply With Quote
Old 12-07-2018, 15:32   #21
Registered User

Join Date: Dec 2014
Location: Brisbane, Qld, Australia
Boat: Fastback 43 catamaran
Posts: 195
Re: Troubleshooting NMEA 2000 and the troubles with NMEA 200

Quote:
Originally Posted by Reefmagnet View Post
I have a mixed network comprised mostly of Simnet (which I think is just about all but obsolete now) and NMEA 2000 (and NMEA 0183, too!). I vaguely recall that although Simnet allows daisy chaining of devices (akin to having multiple devices attached to a single NMEA 2000 drop) it only works for some devices and some care is required in connecting everything to ensure that the same "backbone and dropper" structure of a standard NMEA 2000 network is maintained.



For cleaning the Simnet connector at the masthead, I'd suggest not using any abrasives, but just giving the connection a good flush out with contact cleaner. Apply silicon grease to the plug and socket before reconnecting to protect against moisture and corrosion.
I agree with ruling out power problems first, is it possible that a fridge, or water pump cycles on and momentarily drops the voltage. Check common negative connections for corrosion or loose wires. Intall a 5 to 10 watt globe on the same fuse as the instruments and see if it fluctuates or flickers
Sardean is online now   Reply With Quote
Old 12-07-2018, 23:52   #22
Registered User

Join Date: Jun 2013
Location: canada
Posts: 1,996
Re: Troubleshooting NMEA 2000 and the troubles with NMEA 200

get a heat gun or hair dryer and point at stuff. see if you can figure out where the issue is. or narrow it down.

I have never seen a heat issue.
smac999 is offline   Reply With Quote
Old 14-07-2018, 11:47   #23
Registered User
 
macman4190's Avatar

Join Date: Jan 2017
Location: Waukegan - Lake Michigan
Boat: 1979 Islander 36
Posts: 55
Re: Troubleshooting NMEA 2000 and the troubles with NMEA 200

Quote:
Originally Posted by transmitterdan View Post
Can you temporarily disconnect the mast cable and replace that with a termination? Then run the network for a while to be sure the problem really is up the mast.


I lost my network several times due to issues with the mast connection and had to remove it and plug in a terminator.
macman4190 is offline   Reply With Quote
Old 15-07-2018, 17:22   #24
Registered User

Join Date: Jul 2015
Location: Melbourne Australia
Boat: Timpenny 770 7.7m
Posts: 20
Re: Troubleshooting NMEA 2000 and the troubles with NMEA 200

Quote:
Originally Posted by Suijin View Post
...and then after another couple of hours motoring at the end the network again went down, of course just when i was entering port with shallows...and no depth sounder. Has anyone heard of or experienced heat-related issues with NMEA 2000 cabling/junctions?

Just on another angle, have you considered it might be voltage related?? After a couple of hours of motoring, your batteries will be fully charged and be around 13.8 Volts, possibly higher. Is one of your instruments reacting to the higher voltage and not working, possibly overheating internally? Can you switch the instruments onto the house bank so that the engine is not chargeing this bank and see if the problem still occurs?
Quietta is offline   Reply With Quote
Old Yesterday, 02:49   #25
Registered User

Join Date: Feb 2015
Posts: 288
Images: 1
Re: Troubleshooting NMEA 2000 and the troubles with NMEA 200

Chances are about 5% that it's a cabling problem, and 95% that it's a device problem. You have ruled out heat already, which is good.


What are the exact devices on the network, and in what topology? Can you post a sketch showing it all, including approximate cable lengths?


Since the problem reproduces when not underway, I think you just need to bite the bullet and start segmenting parts out of the network and see when the problem stops occurring.


Another test would be to see if the AP can see any other devices when the failure occurs. Most have pages where you can see what's on the network, and most will alarm if they lose things like rudder, compass, etc. It may be that the MFDs are losing communications, but the devices are still working fine and the AP can see them. The point it that just because the MFDs can't see any of the devices doesn't mean that all those devices are inoperative.
__________________

__________________
www.MVTanglewood.com
tanglewood is offline   Reply With Quote
Reply

Tags
nmea, nmea 2000

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Troubleshooting solar setup... or troubleshooting my troubleshooting!! basssears Electrical: Batteries, Generators & Solar 142 19-07-2018 22:20
Raymarine acu-200 and Lowrance Elite nmea 2000 set up MB23 Marine Electronics 1 26-11-2017 21:11
Troubleshooting NMEA 2000 Systems on Boats SuenosAzules Marine Electronics 0 05-12-2015 19:37
Help troubleshooting my NMEA 2000 network Toubab Marine Electronics 7 25-03-2015 15:03
little wonder 200 water maker - help troubleshooting RickyEM Plumbing Systems and Fixtures 18 11-01-2014 07:31



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 15:36.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.