Dr. Yung’s NMEA 2000 lab, Ship Convergence Center too!

Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

19 Responses

  1. Kees says:

    “NMEA 2000 — which sometimes seems rather local to the U.S. and yachting –”
    Ben, now you’re just being self centered 🙂
    Of the four major players in yachting three are non-US (or at least mostly so.)

  2. Richard C says:

    It seems to me that NMEA, historically, has been slow to innovate and add needed PGN’s or accommodate new product certifications for small start up marine electronics companies. What’s to stop AITASC from competing by issuing their own CANbus standard and moving quickly to accommodate the fast pace of development in a more cost effective way. Haven’t I read many a post here complaining about how hard it is to work with NMEA and how expensive it is to get approvals? Does that leave the door open for another self proclaimed standard using all the same hardware? Please be aware, I’m not an engineer only an end user so maybe this is really not possible, but I thought it worth asking anyway.

  3. Ben Ellison Ben Ellison says:

    Richard, don’t believe everything you read on Panbo 😉 I do wish that PGN writing process was faster, but I think that the rap about how NMEA is just a club of major manufacturers keeping small companies down is blarney. Hopefully, the involvement of Dr. Yung — who became a big fan of N2K because he likes the technology — are another indication that NMEA is more open than some might think and that CANbus was a better idea than some may think. And maybe the engineering horsepower at KMU can help move things along quicker.
    Kees, you’re quite right; there’s great N2K development happening in Europe and New Zealand and elsewhere. But it is a bit odd that two of the most critical players in the protocol’s development — former NMEA Technical Directors Frank Cassidy and Larry Anderson — both live near me in fairly rural Maine (well, Larry splits his time with Arizona). I was not very articulate, but it seems good for N2K that folks who are not from the western world of yacht electronics are getting into it.

  4. Dan Corcoran (b393capt) says:

    The students have the NMEA 2000 documentation ?

  5. Ben Ellison Ben Ellison says:

    Definitely, Dan, though it’s partially translated to Korean, or maybe parallel translated, I couldn’t tell. This is not a wildcat operation; Dr. Yung and some of his colleagues have been to NMEA conferences and the current NMEA Technical Director Steve Spitzer has been to KMU.

  6. Powerabout says:

    Whilst nmea 2000 is single bus technology as in suffers from single point failure it wont be replacing nmea 0183 on anything that the IMO certifies

  7. Kees says:

    That is why they will have to have two of everything: two CAN and two LAN.
    See the blue and red lines in the diagram above.

  8. Yung says:

    Yes, Dan. Almost of Korean feel hard to understand English document and time consumed. So I completed parallel translated for NMEA document under MOU between NMEA and MEIPA. It is very useful for Korean company staff to understand and develop NMEA 2000 device.

  9. powerabout says:

    So they are proposing 2 cable drops from each device to get over the original single point failure issue.
    That might get it headed toward the IMO but I guess that added expense wont make the US pleasure boat industry happy with the cost and extra work.
    SAM electronics of Germany already does the above via their propitiatory bridge technology as found on most cruise ships, you can load any nav screen on any screen on the bridge ( including the DP console assuming the console has a joystick)

  10. Ben Ellison Ben Ellison says:

    Powerabout, you seem determined to find something negative with what is going on. Who said that dual N2K IMO-approved hardware would have to be used on pleasure boats? When has that ever happened?
    But if the NMEA 2000 protocol does become part of eNavigation (though surely with more rules layered on top) won’t that mean that more companies and engineers will work at extending the protocol? What’s wrong with that?

  11. Powerabout says:

    Hi Ben
    Nothing wrong at all but I cant see where it is going, will you end up with 2 versions of NMEA 2000 equipment and specifications one for commecial and one for pleasure boats?
    To me NMEA 2000 was invented for the demand from 12v pleasure boats to enable devices to talk to each other without a computer to redistribute the data, and yes its great at that.
    It was designed to allow a very simple wiring in the (small 6 meter cable length)boat factory to be installed and very simple to extend.
    The current connector spec is so poor thats were most problems are so there will need to be plenty of changes.
    So back to my question of where is it going?
    Heading for commercial quality in component and connectivity design or is this to help to make a quick and simple system for cost conscious pleasure boat builders?
    There are a few NMEA 2000 vendors that do both, I would love to know what they would be pushing for?
    Perhaps it needs to an all new NMEA 3000?

  12. Ben Ellison Ben Ellison says:

    Powerabout, it’s pretty obviously going the same way as NMEA 0183, but potentially much better. 0183 is used in heavy commercial and recreational marine and elsewhere and doesn’t even have a cable/connector standard. Of course the hardware is different, just as the scale of the vessels is quite different, but a common data protocol is good for all. Version 4 of 0183 probably deserves more attention than it gets in our world but that’s because it was largely driven by the needs of the commercial market and related organizations like the U.S. Coast Guard: http://goo.gl/2iHkp
    And why cite the smallest number in N2K network topology, the 6 meter (20 foot) maximum drop from the backbone to a device? Besides that restriction, here’s the maximum dimensions of a basic network:
    • Number of devices does not exceed 50
    • Maximum Mini cable distance between any two
    devices does not exceed 250 meters (820 feet)
    • Maximum Micro/Mid cable distance between any two
    devices does not exceed 100 meters (328 feet)
    • Maximum cumulative drop line length does not exceed 78 meters (256 feet)
    That covers quite a lot of boat, and can be easily extended using bridges that share data but separate power. Boats can also be set up with multiple N2K networks that are bridged together by Ethernet as Furuno NavNet used to do and as will surely be supported in OneNet (and in the eNavigation topology shown above, if it comes to pass).
    There’s nothing wrong with the DeviceNet cable and connector standard that NMEA chose to use for N2K. It has already proven itself exceedingly robust, and I suspect that we’ll see something like it chosen for OneNet. The one mistake NMEA made, I think, was to allow vendors to use their own N2K connector on their own devices. Several used that loophole to design their own N2K-like cable and connector sets, which were not NMEA certified but also not illegal.
    But that’s almost over. LowranceNet is long gone. Simnet is on its way out. These days Raymarine goes out of its way to make it clear that the SeaTalkNG connector and cable system can be used with standard N2K devices or vice versa (which was always true but not obvious). The only recent company I know of to try a proprietary NMEA 2000 connector, Fusion Marine Audio, apparently has regrets or at least has seemingly switched over to a standard connector on its new 700i stereos.
    BTW, have you ever handled NMEA 2000 Mini size cabling and connectors? I doubt there’s any other data cabling on a vessel of any size that so heavy duty.
    In short, I think that you underestimate what was conceived of for NMEA 2000 from the beginning, and we still haven’t experienced the related OneNet Ethernet standard that was also in the original game plan.
    For an example of how at least one company is bringing NMEA 2000 economies and efficiencies up to the light commercial and even IMO approved world, check out Simrad Professional’s brand new GN70 Navigator and AP60 autopilot (with thruster control):
    I don’t know the competition at this level, but it sure looks like Simrad is leveraging its recreational marine N2K expertise into attractive commercial products. That can go the other way, already is when you consider Dr. Yung’s work at KMU.

  13. John Konrad says:

    Now why doesn’t King’s Point have a lab like that, oh yes, it’s because they don’t do any research….

  14. Powerabout says:

    Hi Ben
    Yes I agree a single standard would be great and then the only choice might be IMO approved where needed or pleasure boat stuff.
    RE the AP60, only has a canbus connector therefore couldnt be IMO approved could it?
    If the standard jumped to dual bus then it would get the attention of the commercial kit guys I would assume.
    Lets hope Dr Yung can get that moving.
    Re my comment on the conectors its not the design I think its the quality, just about every time I have been on a boat with an instrument problem its a n2k connector that is faulty

  15. Ben Ellison Ben Ellison says:

    “just about every time I have been on a boat with an instrument problem its a n2k connector that is faulty”
    Really? That seems odd as I’ve never seen that problem while using just about every N2K instrument and cable type in existence. Nor do I recall any of the many Panbo readers who use N2K mentioning a similar situation.
    No doubt there are quality differences in NMEA 2000 certified cable systems but I think the range is good to great. If you’re using a fully metal mesh shielded cable with metal to metal connectors (Maretron style) you probably don’t have a stronger, more waterproof cable connection anywhere else on your boat.
    At any rate, I am skeptical about anecdotal evidence from an anonymous skeptic.

  16. Powerabout says:

    I appreciate I am one person with one story.
    it was Garmin plastic connectors.
    If you touched or put any pressure on them they stopped or started working.
    The Maretron are very nice
    that should have read
    “just about every time I have been on a boat with a N2K instrument problem its a connector that is faulty” –
    Great site here with plenty of information

  17. Ben Ellison Ben Ellison says:

    Today I was pleased to learn that IMO-style redundancy is already built into the NMEA 2000 standard and its IEC 61162-3 counterpart, and it’s more flexible than some might think. I also learned that “the NMEA 2000 cable and connector specifications have been accepted by Lloyd’s of London on use of all sizes of commercial vessels”…and also have been…”approved by the USCG CFR 46175.110 for use on small passenger vessels.”
    A big thanks to NMEA Technical Director Steve Spitzer for the clarification. Steve also send along an extract that spells out the specifics of N2K redundancy for SOLAS vessels:
    “IEC 61162-3 specifies two types of devices, those with one interface (Class 1) and those with two interfaces (Class 2). Redundancy may be achieved with two buses, with functions duplicated on each bus, thus providing function and bus redundancy at the system level. Duplication of function on a single bus provides function redundancy at bus level only. System redundancy requires two buses. Function redundancy may be met by having multiple Class1 devices on each bus or Class 2 devices on both buses. Function redundancy can also be achieved with a combination of Class 1 and Class 2 devices across redundant buses.”
    In other words, SOLAS requirements can be met with special Class 2 N2K devices with dual connectors but it can also be done in whole or in part using more familiar single interface devices on dual backbones.
    Also built into the standards is a way that Class 2 devices can “provide a means to identify messages that are received from redundant buses as being the same or different.”
    Sounds like the whole thing is pretty well thought out and has received at least most major approvals.

  18. Powerabout says:

    Interesting news,good to know that was the intention from day one.
    Thanks for that update.
    Does anyone make two interface devices yet?

  19. Amin says:

    Thank you for your great article.I am going to join to Professor Yung’s lab this fall.after reading your article I became so excited to join to his lab as soon as possible.

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