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Greetings, just bought a 2008 Hanse 470 with a mix of unique tech/networking.

The previous owner had 2 Nav system (1) an Unbuto based Open CPN system running on an old Intel I3 box with a VGA monitor display (2) a Triton B&G chartplotter on a NMEA 2000 backbone.
Hopefully the image i hoped to attach is visible,

If you can see the image, you will note that (1) there is a Rasberry hub in the Middle with connection to
  • an older Garmin 1083 Auto-Pilot,
  • a USB based older GPS Puck,
  • AIS feed,
  • NMEA 1083 <-> 2k converter,
*a wifi routner.

M goal is to get as close to a functioning NMEA 2000 backbone, Get rid of the 7 year old slow Unbutuu box out of the way, and use the existing AutoPilot and AIS GPS for another season.

Question 1: can anyone explain what the Rasberry does? Is it multiplexing,
Question 2: will this work better - run everything off of the B&G chart pllotter and forget about the Unbuto box.
(a) connect the AutoPilot to the NMEA 2K backbone with a dedicated NMEA 2k <-> 1083 converter box
(b) connect the AIS to the network with a dedicated NMEA 2k <-> 1083 converter box
(c) buy a high accuracy GPS antennae and connect it directly to the NMEA 20 Network.

Question 3: Why is everything connected to a wifi router - specifically the radar?

Question 4: why is the radar connected to the wifi router and can it connect directly to the NMEA 2k backbone?
1- It seems clear the Raspberry pi is used to get all the information on ethernet from 183 and 2k to connect to OpenCPN. It can also allow routing gps, depth..ect to the Zeus. It provides AIS to openCPN and possibly Zeus.. You seem to have an issue that not everything is able to talk 2k.. so the PI converts these 183 devices to ethernet.. it also connects your 2k devices to ethernet.

2- Depends if Zeus is able to do something with all the data. OpenCPN can digest a multitude of sources. Your 183 devices dont seem to be able to talk 2k.. so the only solution is convert 183 to 2k.. which your existing solution can provide through the PI. Or the 183 can connect to ethernet through the PI.

3,4- Radar must connect ethernet.. 2K is way too slow to send high precision radar across. It could be that the PO realized the radar must connect to Zeus through ethernet, so just added the router and connected everything else up also.

I somewhat agree the existing system seems a bit dependent upon a variety of different pieces.. it is not clear all of your pieces would work properly with 183/2k converters.. the fundamental issue is that 183 is not able to digest all the information coming from 2k.. so the 183 converters will be overloaded without some type of sentence filtering.. the PI is capable of filtering certain sentences.. depending how it was programmed.

As a side issue.. the future is ethernet.. not 2k
 

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"Thanks, would you recommend connecting everything through Ethernet and the the PI.'. CPN seems great but I am trying to decipher a bunch of ETL code all day . Is there some way to use these open source tools without having to learn all the libraries for each device and processor?". I tried to buy Simrad end point devices but they all seem to be protocol constrained, in this case nm2k. Can I just wire the boat with Ethernet"
Thats an interesting problem.. i was trying to think what i would do in your shoes.. Unfortunately, ethernet is not really much of an option with your current electronics other than the way it is done through the PI or an intelligent converter..

When i said ethernet, i was referring to all its forms such as wireless in addition to wired. Once the information is in the router.. it can be wirelessly sent to any computer. Devices such as Zeus can talk wired to the router. If you want OpenCPN.. but don't like Ubuntu, you can use any newer Windows PC.

To allow bi-directional 183, some type of sentence filtering will probably be required.. and thats done in the PI.. So is your ETL implementation using some sort of ETL libraries with Python or C? Seems like over kill.. but i have not researched any open source conversion programs because i would just write it myself in c.

So sorry i can't offer any advice there..
 

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I know sailors that like to connect all sensors to a computer to log sensor values and display on the ship computer (Ubuntu in your case).

I use OpenCPN exclusively for route planning offline.. I use a Garmin plotter for online navigation, AIS and radar overlay.. My computer has its own GPS device, so it needs no sensor data.

i would tend to agree with others if you do not want a computer connected to your sensors..

To create this sort of solution.. I would connect the radar directly to the Zeus for radar.. 183 from the VHF to Zeus for AIS..

The autopilot does not need wind unless you usually pilot to wind... in this case the autopilot directly connects its fluxgate..

I am not a fan of connecting single sided CAN to differential can, so i would be careful about connecting these three different 2k manufacturers together.. this would mean the 2k connects only to the Zeus. And Raymarine connects directly to its fluxgate.

This is probably the simplest solution that gets rid of ethernet, ubuntu, PI and all converters, without buying anything.
 

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Not sure I understand your point about single sided CAN to differential CAN. I'm not even sure that is even valid electrically, since every single component listed is differential - even the converters. There isn't any such thing as "different N2K manufacturers" because N2K is just a standard that all manufacturers have to meet. There aren't different "flavors" of N2K, and even Raymarine's perversion of it is simply in the physical connectors only. Even the Seatalk converter to N2K meets the standard and works fine.

So put everything on the N2K bus and all will happily share data and work together.

Not having wind or navigation data available to the autopilot is severely limiting its functionality and usefulness. It can easily achieve all of its potential by connecting it to the main N2K network via the ST-N2K converter. Of course, the compass, rudder reference, and control head will all be directly connected to the AP computer, but the AP computer will be bridged to the N2K, so all wind, GPS and navigational data will be available to it, and its compass and rudder data will be available to the other components.

The above is from direct experience. We have a ST6001 AP system connected to a N2K bus that also has a dog's breakfast of different manufacturer equipment, including two 0183-2000 converters, and a Standard Horizon VHF/AIS. No problems at all with this.

Mark
The network shown has two different versions of CAN.. Raymarine setalk and 2k.. the PO specifically did not connect these two networks together.. rather, he connected them together through the RP.. so no he did not connect the 6001 to 2k

And yes, there is single sided and differential can.. there is also galvonic isolated and non-isolated can.. as far as i know nema 2k is only the protocol and the hardware is CAN.. usually DeviceNet..

Most CAN circuits separate the electrical driver from the CAN controller chip because the semiconductor circuitry is different technologies.. so the designer make make his own driver.. when i put CAN on one of my designed boards, it is always galvanically isolated and differential.. automobiles and most n2k are not isolated, so drivers can often be blown due to issues with ground currents and transient bursts..

I have seen drivers get blown on marine N2k networks (on my boat also) because they are not quite as compatible as we would like them to be..
 

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Concerning autopilots.

I believe most newer autopilots will interface with a GPS plotter and steer to a waypoint. But can those APs simply be set to steer a magnetic course?

Are you using your AP to steer to a fixed coordinate (waypoint) or to a magnetic course (to a waypoint or mark/feature of the land etc.? Do you rely on tell tales, a windex or wind data on instruments when sailing with the AP?
these are excellent questions..

I run almost exclusively to compass course.. quite simply because i may be tacking.. kind of hard to tack if your GPS is calling the shots.. also.. i am often dodging things.. crab pots, other boats.. buoys.. again.. GPS cannot provide me this functionality..

I mostly run to flux while in the rivers and ICW because course corrections need to be made due to different buoy locations.. same with coming into or exiting inlets..

I sometimes will run to wind.. but rarely..

Running a 200 or 300 mile run, winds will often change causing me to change course to get a more favorable speed. As a result of these issues.. i rarely run the auto pilot with the GPS.. on the other had, i am always following a course on the GPS.. even if i am tacking back and forth across it..

Since Raymarine comes with a flux compass.. more than likely this owners boat did not need a connection to the 2k compass.. So he could probably disconnect and run to compass.

Probably the best investment I made was replacing the old Raymarine 4000 iirc.. with a new Raymarine Evo.. the 9 axis accelerometer sensor has the autopilot turning the rudder as the boat slews through waves even prior to being off course.. it reacts like a human pilot..
 
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