NMEA 2000 network troubleshooting with Digital Yacht, Actisense, and DIY Tools

Ben Stein

Ben Stein

Publisher of Panbo.com, passionate marine electronics enthusiast, 100-ton USCG master.

15 Responses

  1. Fred Murphy says:

    Another great article. A couple of Led terminators and a breakout NMEA 2000 breakout cable is a good start for a toolkit for helping others. I also like info on CanBus networks. It’s very common in cars, boats and many automation circuits.

  2. Fred Murphy says:

    Also interested in further information on using the oscilloscope to further diagnose things. Never receive any training on what they can do!

  3. abbor says:

    When using an oscilloscope for NMEA 2000 diagnosis I’m using a differential probe to connect to the bus and I’m looking at the eye diagram.

    https://www.testandmeasurementtips.com/basics-eye-diagrams/

  4. Grant Jenkins says:

    Good article, Ben. In addition to the “…. first two thoughts are power and termination”, I would also add any field-attachable connectors in the system. As I’m sure you know, these can be really challenging to assemble, and any extra resistance or an open circuit is sure to cause trouble. I was able to borrow one of the Maretron N2K meters last time I had to trouble shoot a problem, and with that and a breakout cable it was pretty easy to find the culprit.

    • Tim Quigley says:

      Grant, great point about the field installables.

    • abbor says:

      I don’t understand what’s the problem with field attachable connectors. I’ve used them for more than 10 years, very easy to install and reliable.

      • Grant Jenkins says:

        Well I can only speak for myself, and the issues I’ve discovered while troubleshooting them. I’m familiar with the Mareton product – perhaps there are other’s that are easier, but I’ve not met anyone who would describe them as “very easy” to install. In particular, if you don’t add a section of heat-shrink to the bare conductor (“recommended” by Maretron but not included in the kit) you’re almost guaranteed to have problems.

  5. abbor says:

    I have mostly used the Maretron connectors. For an EE with 30 years experience in product development it’s very easy to install these;-)

  6. Grant Jenkins says:

    OK, if you say so. Apparently my skills need sharpening. For me, I’ll continue to stick with factory-installed cable terminations, and eliminate any possibility of a bad connection….

  7. abbor says:

    We use these connectors, both Micro and Mini in a product I’ve been involved in developing. I’ve also used them in my boat. It’s not originally Maretron connectors, they are just marketing these. it’s Molex Brad Mini and Micro Change connectors, developed for DeviceNet industrial networks. It’s the easiest connector I terminate, all other connectors I terminate for lab work or prototyping are more challenging, most of them much more challenging to terminate involving soldering or crimping.

    • brk brk says:

      Exactly, it’s a standard M12 connector that you can get from Digi-key for about 1/2 the price. I keep several handy and have not had any problems with them, but then I’ve done thousands of telecom and audio terminations over the years.

  8. Wolfgang says:

    This video on Youtube has also some nice throubleshooting tips for a CANBUS (applies to NMEA2000 too, as it is a CANBUS):
    Name: CAN Bus Properties and Troubleshooting
    Link: https://youtu.be/ulcKnrPmJqM

  9. Maybe someone can explain what it means if I tested the resistance with power off and my multimeter showed 116 ohms. Does that mean I am missing a termination at one end of the backbone? Thanks.

    • Wolfgang says:

      For sure you miss one termination on the bus:
      – The terminater itself can be broken (I had this with a brand new one, it dus not have to effect the canbus with only a few devices, so you will only notice this when measuring it with a multimeter). Replaced the terminator itself, easy fix.
      – The backbone is not connected properly. Something lose?
      – Broken wire in the backbone.

    • brk brk says:

      A missing or broken terminator would be the most likely scenario if your bus resistance is too high.
      For *most* simple networks (eg: any average pleasure boat) you might not ever have any problems, though if the remaining terminator failed, then you might start having a lot of collisions on the network, or other problems with corrupt data and signal integrity.

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