Angry about NMEA 2000

wingssail says:

Help me out here. What is there about this diagram which precludes use of NMEA0183?
So you do away with a couple of multiplexers, what else?

Andrew says:

My question is, why not use 0183 over a tcp/ip network?
TCP/IP is great for multi node networking.
This has been bugging be for while. Is the power consumption required to maintain the network considered to high? Or is their some other reason.
thanks.

Mike Keizer says:

Hello,
I was looking in the Internet for some NMEA 2000 information. I have a small experimental program running at home which distributes NMEA 0183 messages from different sources (GPS’s at the moment) over WLAN (g and b) and Ethernet(10/100Mb). It uses UDP since the information isn’t critical. By adding some extra information at the end of the NMEA message I can even differentiate equal senders, tell a Garmin from a Maggelan GPS. At the moment I don’t see a reason why, on an enclosed environment ethernet, wlan or maybe even bluetooth couldn’t do the job of information distribution. Where the wireless solutions would save the burden of putting more wires everywhere. Cheers Mike

Mike Keizer says:

Hi Ben, I’m not really very actively following this discussion. I’m sorry. I don’t see a reason not to build in a ethernet interface on all the devices you mention. If it fits on a PCMCIA card in my opinion it can fit on anything. It basically comes down to the decisions the manufacturers make. Collecting it is a matter of architecture and bus you want to use. CAN, Profibus, WLAN, Ethernet, Bluetooth or why not USB? In a lot of the cases it will end up at a PC with an application on it. I agree with your conclussion that we’ll in paractice end up with more than 1 kind of bus in one place.

Nick Belson says:

Guys,
I have just stumbled accross this thread. We are in the process of developing a small box for routing multiple channels of 0183 data and broadcasting it over UDP on Ethernet, with a UDP receive driver that pretends to be a com port on your PC, so PC apps can think they are directly connected. This has the added advantages that it can be routed over WiFi, so the chase boats on the big racing yachts we work on can also catch the data. Any one have any requests for features we can add in?

Spectator says:

WiFi data transmission can run into problems – what if your data is received by another boat close to you? Or vice versa? Confusion and bad things could result from that disorder. Most eqipment sets up using a default address – and let’s be honest – most boaters will go with the default – too complicated to actually specify something on a network. Everyone wants something that will work out of the box – no issues – no ‘hassel’ setup. I would stay away from general wifi ethernet ideas, you would require a more secure setup to run such systems.
The new wireless pilots from Raymarine are a step in the right direction – this is still a proprietary communication protocol, requiring the hand unit be registered to the control station.
NMEA 2000 will makes things more simpler. It’s just one long wire run – no multiplexors – just unit after unit after unit. No looping back – all the connections are standardized – and designed to live in oily wet locations.
It is true that all wire runs end in a PC – even if that PC takes the shape of a Furuno 1953c display. It’s just wanting to talk in it’s own lanuage to its own family. What you want is that when NMEA 2000 starts hitting big, and I think it will, that you will now be able to connect a Raymarine E120 to a Simrad pilot simply by connecting 1 cable. No configuration required.
It’s up to the manufacturers to enable this through their software. It is a business, and the competition is always a concern – of course they want to design products that steer you in the direction of buying all of their products.
The ultimate goal of 2000 would be a plug and play network. I’ve had my hands on the actual cables and seen the connectors to be used. It really will be a good thing. It will provide a much more comprehensive on board network that will be less of a hassel than 0183. 0183 works great to a point – then you start having to make the system so much more involved than what it should be. But rememeber the era that 0183 was developed – we didn’t have WinXP, Google, WiFi, machines running @ 3.5GHz.
It’s all relative.

GAVALAS ATHANASIOS says:

HI FROM ATHENS
PLEASE.
HOW CAN TRANSMIT AIS DATA FROM AIS ENGINE RS232 OUT
OVER RF (VHF OR WLAN MODOUL )AS AIS REPEATER OR LINK .DO YOU KNOW ANY INTERFACE FOR THAT PURPOSE.
THANKS
THANASIS GAVALAS
ATHENS
HELLAS
[email protected]

THANASIS GAVALAS says:

THANKS BEN
CAN I USE A MODEM OR TNC IS THAT RIGHT .IN THAT CASE WHAT SPECIFICATIONS MUST SUPPORT THIS MODEM OR TNC.
I VISIT ALSO cmlmicro.com THEY HAVE INTERESTING PRODUCTS (GMSK MODULATORS…).
THANKS
THANASIS GAVALAS

Andrew Smith says:

Hello,
I have been quietly waiting for you to address user end firmware updating and am hoping this will be a gentile reminder 🙂
In my case, I have a Raymaine ST290 system. One of the reasons I bought it was the USB port on the DPU and the promise of easy upgrades via the DPU (see section 1.3 of the manual ‘System Upgrades’
http://www.raymarine.com/raymarine/SubmittedFiles/ST290_sect_01_iss2.pdf
I have now had the units for a few years and there have been a number of firmware upgrades, so I called up the support number. I was first told that it was not possible for a user to perform these upgrades, even if the user is a unix systems engineer, then later told that there was a �software upgrade kit� but the highly recommended sending in the units.
I explained that I would rather give the kit a try and if it failed, then I would send them in. Frankly ripping apart lots of cabinetry is not something I want to do unless there is no other way, plus they pretty much make a point out of easy user upgrades in the manual.
The tech I was speaking with didn�t know the part number for this kit, and transferred me to another, who pretty much said, uhhhm then I was back on hold. Then another tech had no idea, I was on hold again.
Finally I ended up with someone who told me there was no such thing and that there had been no firmware/software upgrades. I pointed out the table �Latest software summary for ST290 series instruments� on the web site, still he had never heard of a kit and the only way to have the serviced was to send them in.
This just seems wrong. Has anyone else been able to get what�s needed to perform these upgrades?
Ben, maybe you know someone with Raymarine who can provide an explaination.
Thanks.

Pete Dubler says:

Will they ever learn? Closed standards, NMEA-2000 specifically, only encourage development of alternatives that are cheaper to implement. The $10,000+ to put a single device on the NMEA-2000 bus is outrageous (and I’m being nice).
The computer industry had to learn this during the 80’s and 90’s. When will the marine electronics industry learn it? Open standards are good for business, the industry, and most importantly, the consumer.
I spent 16 years with a once great company, HP, and saw them go from closed standards to open ones during the 80’s and 90’s. Business boomed everytime a proprietary standard was thrown out in favor of an open standard. Replacing proprietary, networking protocols and hardware with open LAN standards, graphic libraries with OpenGL, proprietary unix implementations with Linux, etc. Every time the move was to open standards, sales increased, prices went down, and customers benefited.
NMEA-2000, as a closed, proprietary, fee-based club is bad for bringing new innovative, small players into the industry (protecting the less fleet-of-foot old companies), and just keeps prices high for the consumers.

Guest says:

BTW – the update process is not as clear as you might think – that is another reason the software isn’t for public download. You gotta have a guy that knows what he’s doing to update the 290’s, they’re not cheap instruments, let someone else kill them – then the cost is their burden – not yours. You try to update and kill them – you just cost yourself a bit of money.

Guest says:

Andrew,
Good, glad to hear you got what you were seeking, maybe you need to drop the DPU software version first in order to upgrade, also…check the serial number in the graphic dealer menu – if it says – not set – it won’t accept any software and needs to be replaced – this may be of great importance to you, again contact your local dealer regarding this – they will more than likely talk to Raymarine, very limited issue there.

Roger says:

1. The NMEA 2000 hardware specification is a derivative of the CARS specification. CARS is used by the auto industry. Now we know that automobiles don�t get wet, vibrate, get cold, aren�t based on 12 Volt DC, etc. so there is no way that the marine industry could adopt a standard where the production is millions of units a year resulting in very low hardware costs if they could modify the specification so that it was propriety.
2. You confuse content, protocol, and transport. The majority of the NMEA 183 specification is content � what the messages look like. There is a hardware protocol (4800 baud, etc.) and a transport (two wire voltage.) Both the industry and individual developers and hobbyists move NMEA 183 messages over all kinds of transport/protocol implementations � Ethernet, USB, RS-232, 802-11. The messages remain the same. It is true that NMEA 183 is missing certain kinds of messages, but that is why the specification went through a variety of implementations (e.g. 1.0, 2.0, etc.) There is no theoretical reason why the new message specifications could not have been added to the NMEA 183 message set. All you need to do is add a new message format. Its been done before, it could be done again.
3. You assert that something like a throttle control or a speed sensor could not run on NMEA 183. Perhaps running on a 4800 baud 2 wire link could be limiting. But you could still send NMEA 183 message formats (if they existed) such as throttle up and throttle down over a faster transport/protocol � e.g. USB 2.0 at 4 megabits per second or Ethernet at 1 gigabit per second. At USB 2.0 speeds you could be sending thousands of throttle control messages per second � far faster than the engine could ever react. Remember that an engine running at 3600 RPM is only running at 60 revolutions per second. Even if you sent one message per revolution you would only need 60 messages per second to control speed. Your bandwidth utilization would be very small. Don�t forget that all these mechanical devices have inertia anyway, they can�t react all that quickly no matter how many commands you send them.
4. Getting to Ethernet or USB is dirt cheap. The chipsets are in the less than $5.00 range. And yes, you are already seeing the sensor manufactures putting the interface chips directly on their sensor hardware. For example, you can purchase a GPS sensor that directly outputs NMEA 183 GPS messages on a USB interface today. More will follow.
5. Let�s make it hard for the average person to get into the game. Try to purchase a copy of the �holy grail� � the NMEA 2000 specification. Last time I looked it was in excess of $3500. On the other hand every major computer protocol is free in the public domain. Maybe the NMEA 2000 specification comes on a solid gold DVD? It must be something.
6. While we are on transport and protocol let me point out that Ethernet and USB are fundamentally transports. TCP/IP (the �Internet Protocol�) is a protocol � the way that two different computers/devices talk to each other � the envelope in which the message (read NEMA 183 text) is sent and received. Since these protocols are designed to permit millions of computers to send trillions of messages to each other all day long (read �the internet�) they are pretty robust � guaranteed delivery, broadcast delivery, quality of service, multicasting, etc. I can not conceive of a communications requirement at the protocol level that could exist on a boat that doesn�t already exist and is solved on the internet.
7. Finally, you assert that the system on Steve Dashew�s boat is complex. Now I know you are a boat guy, and I love your column and check it most every day. But spend about 5 minutes at any automated manufacturing plant and you will see that in the scheme of technology implementation Mr. Dashew�s boat is trivial by comparison.
This takes me back to the comment in the first post � I pass on the personal characterization and the assertion of the profitability of marine electronics � but I fully agree that the industry and the boating public would be far better served by an open standard that takes the maximum advantage of high volume, low cost, off the shelf components and software implementations.
Roger

Roger says:

Thanks Ben for the response � let me see if I can sort some of it out�
Yes, you are correct that NMEA 2000 is based on CANbus � Controller Area Network – I misspoke. My initial information was that the particular way that the CANbus architecture was to be implemented in NMEA suggested that it would not transparently interface with devices that were implemented for the automotive market. Since I have not chosen to spend the thousands of dollars for the specification I can�t pass on the true or falsehood of this statement.
My most simple point was that CANbus is one physical implementation, the one that NMEA chose, but like all choices it has strengths and weaknesses. In my mind the biggest weakness is that it is slow compared to other protocols. I have worked in manufacturing automation and I can tell you that Ethernet works just fine. BTW,
I have used Ethernet to control things as sensitive as shift and throttle � its no big deal. As I was trying to point out (unsuccessfully) in my post � a higher speed protocol than CANbus might be better for distribution of multiple high bit rate streams (think radar, chart, and full motion video to multiple displays all over a large boat.
I don�t think that an in depth technical discussion would be worthwhile. We have NMEA 2000 and will have it for a while (after all, its 2006 and we are still on NMEA 2000!) My biggest complaint is that even purchasing the message formats is a significant outlay (I think about $500 by the time you are done.) That is a real disincentive to innovation by the great unwashed.
Roger

guest says:

Mike, you make a good point on one way a malfunctioning Ethernet device could bring down Ethernet. My question though is, what would happen if a NMEA 2000 device malfunctioned and either shorted to ground or locks in a high state the NMEA 2000 bus, would the shift and throttle data get through?

george says:

the reason not to use ethernet for critical
applications is that it is non-deterministic.
There is no way to predict the time it will take
for a message to arrive at its destination.
In fact, there is a vanishingly tiny probability
that it will never arrive.
No problem for sending web pages, or even
dropping a few voice packets on a web call.
But if the information to shift gears, change
throttle, or even radar data gets delayed
there are safety (and liability) issues.
I grant you they are small.
But many government specifications (FAA in particular) banned ethernet entirely from mission critical systems for this reason. If there is
a finite mathematical probability of a message
being delayed beyond usefulness, they won’t stake human life on it.
Or in this case, your boat evidently.
As an engineer I view ethernet as perfectly
acceptable. Unfortunately my lawyers do not.
So we use token buses or NEMA2000 (which is
just an offshoot of CANBUS, an industrial manufacturing bus) in safety applications.
I am sure there are other reasons in the
mess that is the marine electronics industry.
No manufacturer I have seen (save one),
uses NEMA2000 in any sort of compatible manner
or without proprietary formats buried in it to
keep us adding on “foreign’ equipment or actually using their equipment in a way they have not ordained. Seems marine manufacturers all take their lead from microsoft.
But at least here is one plausible reason driven
by something other than the avarice of the
marine manufacturers for not using ethernet.
cheers
gello