Help with a complex NMEA 2000 network setup

[chris5977]

My last boat had Garmin which uses pure NMEA2K. I loved this system but I foolishly thought that I should expand my knowledge by using RayMarine in the new boat. I further kicked myself when I realized that the previous owner of the new boat paid big bucks to install a Simrad autopilot that would have been easy to control with a Siimrad MFD had I been smart enough to go that route.

Ultimately I would like to get my SeaTalkNG and SimNet networks to talk to each other. Before I try to connect them I want to make sure my basic understanding of marine networking is correct. I wrote the following primer. Please take a look at it and edit as appropriate.

https://docs.google.com/document/d/1...it?usp=sharing

[phantomracer]

the B+G (unsure about other mfrs) has a terminator built into the wind vane.

there are simnet to n2k cables to easy connect simnet to a backbone

there are converters that will allow direct connect nmea 0183 to Nk2 backbone using a simnet-n2k cable. I used 2 on my system upgrade that I just finished. There is also a high speed converter for heading sensors that are N0183.

The lowrance/navico backbone kits are nice as the connectors are a bit smaller than the normal ones.

cables can be found on ebay used relatively cheap

there are field connectors you can install on bulk wire to make fishing wires easier (but are stupid expensive, but work well)

Big thing is getting the right cables when mixing simnet and n2k

attached is a diagram I made to keep it straight when I did my upgrade.

some pictures of the upgrade and comments on each pic explaining them
https://www.facebook.com/media/set/?...1660004&type=3

.

[chris5977]

Phantomracer,

Thank you very much for sharing your photos of your electronics refit. When I get a little farther along I will post a video of my efforts. Here's some photos:

https://www.facebook.com/chris5977/p...11?pnref=story

Did you read the Google Doc I posted? I'm love your feedback.

I don't have an NMEA2K network on my boat. I have SeaTalkNG and SimNet. They are supposed to be compatible with NMEA2K but in order to truly be NMEA2K it must use DeviceNet Plugs.

[phantomracer]

Originally Posted by chris5977

Phantomracer,

Thank you very much for sharing your photos of your electronics refit. When I get a little farther along I will post a video of my efforts. Here's some photos:

https://www.facebook.com/chris5977/p...11?pnref=story

Did you read the Google Doc I posted? I'm love your feedback.

I don't have an NMEA2K network on my boat. I have SeaTalkNG and SimNet. They are supposed to be compatible with NMEA2K but in order to truly be NMEA2K it must use DeviceNet Plugs.

You just need a N2k backbone, and the appropriate simnet to nk2 wire and seatalkng to n2k wire. (to convert the plug from one style to another) (like this Simrad Simnet To NMEA 2000 Cable Adapter )

all your devices will be off a T off the backbone. it is actually quite simple. check your wind vane to see if it is a terminator as well (will save a T )

'like' my facebook page for updates on mine, if you want

[chris5977]

I have a fully functioning SeaTalkNG backbone and a fully functioning SimNet backbone. Are you suggesting I completely get rid of both of them and run everything to a DeviceNet backbone using adapters? I was hoping there was a solution that did not involve throwing away hundreds of dollars of equipment. Is it possible to connect a SimNet backbone to a SeaTalkNG backbone?

And RayMarine wind instruments do not come terminated. They must be connected to a converter Raymarine iTC-5 Instrument Transducer Converter or an i60 Raymarine i60 Instrument Displays

[phantomracer]

Guess I don't know why there are 2 backbones. Maybe they can be joined to form one backbone

Sent from my SAMSUNG-SGH-I337 using Cruisers Sailing Forum mobile app

[DotDun]

Originally Posted by chris5977

I have a fully functioning SeaTalkNG backbone and a fully functioning SimNet backbone. Are you suggesting I completely get rid of both of them and run everything to a DeviceNet backbone using adapters? I was hoping there was a solution that did not involve throwing away hundreds of dollars of equipment. Is it possible to connect a SimNet backbone to a SeaTalkNG backbone?

And RayMarine wind instruments do not come terminated. They must be connected to a converter Raymarine iTC-5 Instrument Transducer Converter or an i60 Raymarine i60 Instrument Displays

I would connect the 2 networks and see if everything works OK.

You might want to invest in an Actisense NGT (or Maretron USB100, I prefer Actisense) in order to watch/troubleshoot the N2k network.

There are some nuances to STng (other than physical), but they are not electrical, hence connecting SimNet or N2k devices to STng won't 'bring the network' down. Legacy STng devices will peacefully co-exist with SimNet/N2k devices as long as there is only 1 instance of each sensor on the network (i.e., 1 gps, not 2 or 1 wind sensor, not 2). The current/latest RM STng gear don't have this restriction. I've played with SimNet and don't remember any restriction wrt multiple sensors of the same type.

You can add N2k connectors to the STng cabling, the wire color matches between the two, no sense throwing away perfectly good wire. I have never opened up a SimNet cable, so can't vouch for their color code.

If you have the RM wind transducer already installed and it's working, the ITC-5 is a good option, IMO. I'm personally not a fan of running N2k to the top of the mast. Just remember when mixing different vendors equipment, most require their own displays to 'configure' their own sensors, so you won't be able to configure the RM ITC-5 from a Simrad display (as an example). This isn't always a show stopper, as some/most displays allow you to configure internally how the display interprets the sensor data vs. (re)configuring the sensor output directly. This, IMO, is a downfall of NMEA 2000, but it is what it is.

NMEA 2000 isn't hard, I suggest you learn the physical (cable lengths, etc.) and electrical (powering) characteristics first, then with the Actisense NGT, you can learn how the various devices behave on the network.

[Dockhead]

A great idea to write yourself a paper; but there are a lot of errors in it. I'm not an engineer, but I'll try to help:

1. 0183 is based on an old serial data protocol -- EIA422, which means that 0183 equipment is compatible with RS422 ports. It is a point to point protocol, which means any given port can either talk or listen -- it is not an exchange of data like N2K. You can have only one talker connected to any given listening port at one time, but you can have several listeners connected to one talker. 0183 is sort of compatible with RS232 ports commonly found on old PCs. To get around the point to point issue and create a true network, you can use a multiplexer, which is able to combine the data streams of several 0183 talkers into a single data stream. 0183 was issued in several revisions, which are not entirely compatible with each other. Among other things, there are different data rates available, and you have to be sure that talkers and listeners connected to each other are set to the same data rate, and use compatible revisions of 0183.

2. B&G certainly do not use SeaTalkNG -- B&G in fact doesn't exist -- the company was bought some years ago by Navico, and so now all the consumer-grade B&G gear is just rebranded Simrad, sometimes (like in the case of the Zeus) with extra software. Older Navico gear uses Simnet connectors (which a lot of people think are superior to DeviceNet), but some years ago Navico abandoned Simnet and has been delivering all of its gear with standard DeviceNet connectors. Lowrance is another brand of Navico, the "budget" brand, and most Lowrance gear is also rebranded Simrad.

3. Your ideas about "spurs" and backbones are flawed. Everything is connected to the backbone, and you can connect any device anywhere, including at the ends (as long as there is a resistor terminator). The individual devices are connected with "drop cords" or "drop lines" into "T"-connections in the backbone -- they're not called "spurs". You can connect any device of any type anywhere; you just have to be careful to avoid too much voltage drop -- Maretron makes a free and excellent program to design an N2K network and calculate voltage at each device. The NMEA2000 protocol forbids "daisy-chaining" where devices are connected to each other rather than each directly to the backbone, but this does work in many cases, and some manufacturers have made devices intended to be connected like this.

4. The above is subject to a couple of tricks, courtesy of Maretron -- you can buy a "multiport box" which allows you to connect four devices to one box which has a single connection to the backbone. In lieu of daisy-chaining, which is forbidden. You can also buy from Maretron a network interface which allows you to divide a large network into multiple sub-networks. This is useful if you want to power down part of your network at anchor, for example, or to avoid voltage drops over long distances.

5. You can connect 0183 devices to an NMEA2000 network with adapters. My favorites come from Actisense and are inexpensive. These devices translate the 0183 datastream into N2K PNG's. Some of them will even do the reverse translation, so you can get certain N2K data onto a device which receives only 0183.

6. Many plotters will bridge data between N2K and 0183 networks, and this can be really useful. Some data, like AIS data, doesn't always work well on N2K, and some devices -- like my Airmar CS4500 ultrasonic log -- don't speak N2K. Furthermore, you will 0183 output to feed data to your VHF, SSB, Pactor, and any other devices which need 0183 position and GPS data for DSC etc.

I hope that is helpful.

I can't really speak about SeatalkNG, as I haven't used it, but SimNet is 100% compatible in every way with N2K. I have a few devices which use it. You just use an adapter cord and Bob's your uncle.

Concerning compatibility between different makers on a single N2K network --

My experience is that most N2K gear is mostly compatible, but with some caveats:

1. For an "x" brand pilot you will need an "x" brand controller, period.

2. Not all N2K equipment will accept all network commands from equipment of different brands. I've had trouble getting Maretron equipment to accept data source commands from Zeus plotters, for example. Plus not all N2K equipment gives you full control over such things. Source conflicts can be a big problem in my experience, and even small networks these days will have multiple sources for certain types of data.

3. Don't forget the issue of setup and calibration. Usually you cannot setup or calibrate an N2K device from one manufacturer with a device from another. Sometimes you can use a computer for this (Airmar gear can all be set up using WeatherCaster software, for example) but for that you need a USB gateway to connect your computer.

Good luck!

[Dockhead]

Originally Posted by chris5977

I have a fully functioning SeaTalkNG backbone and a fully functioning SimNet backbone. Are you suggesting I completely get rid of both of them and run everything to a DeviceNet backbone using adapters? I was hoping there was a solution that did not involve throwing away hundreds of dollars of equipment. Is it possible to connect a SimNet backbone to a SeaTalkNG backbone?

And RayMarine wind instruments do not come terminated. They must be connected to a converter Raymarine iTC-5 Instrument Transducer Converter or an i60 Raymarine i60 Instrument Displays

Of course not -- just hook them up. They are electrically compatible -- they just use different connectors. N2K networks are not "Devicenets". DeviceNet is an industrial automation protocol. N2K networks just use certain parts of the DeviceNet standards, including the connectors -- which we call DeviceNet connectors to distinguish them from SeatalkNG and SimNet connectors.

Just hook them up end to end without any resistor in the middle, or if it is physically difficult to make one long continuous backbone out of the previous two, then use one of these:

Maretron | NBE100

Use adaptor cables as necessary to get the Devicenet connectors at the ends to connect to that box.

[chris5977]

Originally Posted by Dockhead

A great idea to write yourself a paper; but there are a lot of errors in it. I'm not an engineer, but I'll try to help:

1. 0183 is based on an old serial data protocol -- EIA422, which means that 0183 equipment is compatible with RS422 ports. It is a point to point protocol, which means any given port can either talk or listen -- it is not an exchange of data like N2K. You can have only one talker connected to any given listening port at one time, but you can have several listeners connected to one talker. 0183 is sort of compatible with RS232 ports commonly found on old PCs. To get around the point to point issue and create a true network, you can use a multiplexer, which is able to combine the data streams of several 0183 talkers into a single data stream. 0183 was issued in several revisions, which are not entirely compatible with each other. Among other things, there are different data rates available, and you have to be sure that talkers and listeners connected to each other are set to the same data rate, and use compatible revisions of 0183.

2. B&G certainly do not use SeaTalkNG -- B&G in fact doesn't exist -- the company was bought some years ago by Navico, and so now all the consumer-grade B&G gear is just rebranded Simrad, sometimes (like in the case of the Zeus) with extra software. Older Navico gear uses Simnet connectors (which a lot of people think are superior to DeviceNet), but some years ago Navico abandoned Simnet and has been delivering all of its gear with standard DeviceNet connectors. Lowrance is another brand of Navico, the "budget" brand, and most Lowrance gear is also rebranded Simrad.

3. Your ideas about "spurs" and backbones are flawed. Everything is connected to the backbone, and you can connect any device anywhere, including at the ends (as long as there is a resistor terminator). The individual devices are connected with "drop cords" or "drop lines" into "T"-connections in the backbone -- they're not called "spurs". You can connect any device of any type anywhere; you just have to be careful to avoid too much voltage drop -- Maretron makes a free and excellent program to design an N2K network and calculate voltage at each device. The NMEA2000 protocol forbids "daisy-chaining" where devices are connected to each other rather than each directly to the backbone, but this does work in many cases, and some manufacturers have made devices intended to be connected like this.

4. The above is subject to a couple of tricks, courtesy of Maretron -- you can buy a "multiport box" which allows you to connect four devices to one box which has a single connection to the backbone. In lieu of daisy-chaining, which is forbidden. You can also buy from Maretron a network interface which allows you to divide a large network into multiple sub-networks. This is useful if you want to power down part of your network at anchor, for example, or to avoid voltage drops over long distances.

5. You can connect 0183 devices to an NMEA2000 network with adapters. My favorites come from Actisense and are inexpensive. These devices translate the 0183 datastream into N2K PNG's. Some of them will even do the reverse translation, so you can get certain N2K data onto a device which receives only 0183.

6. Many plotters will bridge data between N2K and 0183 networks, and this can be really useful. Some data, like AIS data, doesn't always work well on N2K, and some devices -- like my Airmar CS4500 ultrasonic log -- don't speak N2K. Furthermore, you will 0183 output to feed data to your VHF, SSB, Pactor, and any other devices which need 0183 position and GPS data for DSC etc.

I hope that is helpful.

I can't really speak about SeatalkNG, as I haven't used it, but SimNet is 100% compatible in every way with N2K. I have a few devices which use it. You just use an adapter cord and Bob's your uncle.

Concerning compatibility between different makers on a single N2K network --

My experience is that most N2K gear is mostly compatible, but with some caveats:

1. For an "x" brand pilot you will need an "x" brand controller, period.

2. Not all N2K equipment will accept all network commands from equipment of different brands. I've had trouble getting Maretron equipment to accept data source commands from Zeus plotters, for example. Plus not all N2K equipment gives you full control over such things. Source conflicts can be a big problem in my experience, and even small networks these days will have multiple sources for certain types of data.

3. Don't forget the issue of setup and calibration. Usually you cannot setup or calibrate an N2K device from one manufacturer with a device from another. Sometimes you can use a computer for this (Airmar gear can all be set up using WeatherCaster software, for example) but for that you need a USB gateway to connect your computer.

Good luck!

Thanks for all the info. You know a lot!

I don't see the point of the Mareton box. I have long cable runs on a 47' boat and everything works flawlessly.

I don't understand why you don't use the term spur. I've been setting up N2k networks for years and the terminology has always been backbone/spur. Look in any manual and that's what they say. http://www.raymarine.com/view/?id=55...nid=9&col=1603



Sent from my A0001 using Cruisers Sailing Forum mobile app

[Dockhead]

Originally Posted by chris5977

Thanks for all the info. You know a lot!

I don't see the point of the Mareton box. I have long cable runs on a 47' boat and everything works flawlessly.

I don't understand why you don't use the term spur. I've been setting up N2k networks for years and the terminology has always been backbone/spur. Look in any manual and that's what they say. Raymarine SeaTalk NG Networking

Cheers.

The point of the Maretron box is to avoid running multiple drop cords to a single location, when you have a situation like that. For example, I have four B&G Tritons and a GPS above my scuttle, and with a single narrow cable duct down to the main electrical panel. It would have been impossible to pull five drop cords there, and even if it had been possible, it would be a big waste of cabling. So the Maretron boxes were a great solution for that type of problem.

As to "spurs" -- I've never dealt with Raymarine N2K gear, so I had never heard that term. It sounds odd since it's not really like a railroad spur, but I shouldn't have said that it's wrong -- not for me to decide