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getting nmea0183 data for dummies!
#1
Operplotter seems to be a great tool, but I'm not sure about how to set up everythin, especially with nmea0183. I have tried to read the documentation but feel that it does not answer my questions regarding nmea0183 connections.
Today I have a pretty old Raymarine system consisting of: plotter (c80), gps, radar, wind sensor, echo sounder, vhf and autopilot. Everything is connected to a box, besides GPS, which goes directly to the plotter (c80). What I can understand is that the GPS is using nmea0183 and goes directly to the plotter,  while other equipment communicates via seatalk and goes thrue the box. The nmea connection is left empty in the box.


The box I have, also Raymarine, looks like this: [Image: view] https://drive.google.com/file/d/18HpL8rW...nMYEQ/view

Now to my question: First of all, I want to connect GPS and the autopilot to openplotter. I have a separate navigation software on a laptop and want to retrieve the information from Openplotter. I have purchased a NMEA 0183 two USB converter from openmarine. However, can I connect both gps and autopilot to the same usb converter? Or do I need to purchase several "NMEA 0183 to USB converter"? Huh 


As you notice, I am a real beginner of this and I feel realy stupid!  But, I would be grateful if someone could easily describe, alternatively, suggest a link, how to get the nmea0183 information into openplotter and then use it on a navigation program on a laptop, for example. I did figured out how to connect the AIS but nmea is harder to understand.
//Patrik
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#2
NMEA connections to OpenPlotter are done with an RS-485 interface converter. Here's a good one:
https://smile.amazon.com/dp/B00XXQ6T3K/r...uzb4968EFZ. Sailoog also has them for sale on his site.

From what I can research, your Raymarine C80 has both input and output ports for NMEA, but keep in mind that NMEA 0183 is a "one sender - many listeners" system. That's why using KPLEX in Openplotter is so cool - you can bring many senders into the RPI, put them all together, and then send them out as if they came from a single sender.

Do you know if the box all your instruments are going into is a Seatalk device? If it is, when you'll open it you'll see a lot of three terminal connectors and little else - Seatalk is a single wire bus system with power (+12V - RED, GND - BLACK, Data - YELLOW). If that is the case, then all your instruments are designed for Seatalk and won't talk to NMEA devices without conversion. Your C80 should be doing that for you, so it should put out a converted stream of NMEA data that represents all the information coming from your instruments.
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#3
small clarification, NMEA 0183 uses RS232, RS422 and RS485 but the standard and most used is RS422
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#4
Thanks for the correction!
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#5
(06-28-2017, 11:00 AM)abarrow Wrote: NMEA connections to OpenPlotter are done with an RS-485 interface converter. Here's a good one:
https://smile.amazon.com/dp/B00XXQ6T3K/r...uzb4968EFZ. Sailoog also has them for sale on his site.

From what I can research, your Raymarine C80 has both input and output ports for NMEA, but keep in mind that NMEA 0183 is a "one sender - many listeners" system. That's why using KPLEX in Openplotter is so cool - you can bring many senders into the RPI, put them all together, and then send them out as if they came from a single sender.

Do you know if the box all your instruments are going into is a Seatalk device? If it is, when you'll open it you'll see a lot of three terminal connectors and little else - Seatalk is a single wire bus system with power (+12V - RED, GND - BLACK, Data - YELLOW). If that is the case, then all your instruments are designed for Seatalk and won't talk to NMEA devices without conversion. Your C80 should be doing that for you, so it should put out a converted stream of NMEA data that represents all the information coming from your instruments.

Thank you very much for the answer

Unfortunately, I'm not at the boat right now but will go there on Saturday and check how everything is connected. However, I have photos on the box and the connections
Marking in the box:
Fluxgate: Here is a total of 5 cables connected. Gnd, red, green, yellow and blue

Rudder: Here is a total of 4 cables connected. Gnd, red, green and blue

Seatalk: 3 cables. Black, red and yellow

In addition to the plotters, I also have 3 st60 displays and 1 autopilot display (st6001 +)


GPS: connected directly to the plotters nmea port

But, will check everything on saturday.

//Patrik
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#6
Patrik
You have a similar setup to me ie Old Raymarine instruments using Seatalk for communications. Seatalk is a (Raymarine) proprietary protocol so there is no direct support for it in Openplotter. In order to get your Raymarine instruments talking to/from Openplotter you are going to need a Seatalk to NMEA 0183 converter. I believe that there are some third party converters (search this forum for links) but I managed to get a second hand Raymarine device They are difficult to find but I bought mine on eBay last year. 
I can now take data from all of my Raymarine instruments into Openplotter and the Autopilot will receive the (converted) waypoint/routing NMEA sentences from Opencpn/Openplotter. You do have to work through issues of different devices trying to output the same sentence but that is what the Openplotter NMEA filters are for.
As I said the first thing you need is the NMEA/Seatalk converter.
Good luck
Steve
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#7
I think in his case his C80 acts as a converter, or at least the installation manual here (http://raymarinec80.com/wp-content/uploa...Manual.pdf) seems to indicate that. I have an ST-60 display that also has an NMEA output but no input, albeit not with appropriate checksums.
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#8
(06-29-2017, 10:00 AM)abarrow Wrote: I think in his case his C80 acts as a converter, or at least the installation manual here (http://raymarinec80.com/wp-content/uploa...Manual.pdf) seems to indicate that. I have an ST-60 display that also has an NMEA output but no input, albeit not with appropriate checksums.

I suspect that the C80 will accept GPS and AIS data via its NMEA port but it doesnt do SeaTalk/NMEA conversion. Thats why there is an "RS232 interface" specified in the Integrated system examples in the manual. (I think the Interface is actually the Raymarine protocol converter) I dont have a chart plotter but I do have a Raymarine course computer with an NMEA I/O port. The NMEA port is only used to get GPS data in. Ive put a laptop running a monitoring app on the port and saw no data coming out eve though there was plenty of Seatalk data on the bus.
Id love to be proved wrong so I can get rid of my Seatalk/NMEA converter Smile
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#9
(06-29-2017, 09:46 AM)affinite Wrote: Patrik
You have a similar setup to me ie Old Raymarine instruments using Seatalk for communications. Seatalk is a (Raymarine) proprietary protocol so there is no direct support for it in Openplotter. In order to get your Raymarine instruments talking to/from Openplotter you are going to need a Seatalk to NMEA 0183 converter. I believe that there are some third party converters (search this forum for links) but I managed to get a second hand Raymarine device They are difficult to find but I bought mine on eBay last year. 
I can now take data from all of my Raymarine instruments into Openplotter and the Autopilot will receive the (converted) waypoint/routing NMEA sentences from Opencpn/Openplotter. You do have to work through issues of different devices trying to output the same sentence but that is what the Openplotter NMEA filters are for.
As I said the first thing you need is the NMEA/Seatalk converter.
Good luck
Steve

Thank you for the tips! I'm very grateful for that. But, if I understand "abarrow" right, the plotter, C80, will convert seatalk signals into nmea0183. So, my plan is to try using that instead. 
If I remember correct, it looks like this:

1. From the gps antenna there is 5 cables. 
- 1 of the cable is seperate and connected to positive+ terminal (bat) 
- 2 of the cables is connected to nmea0183 cable that goes directly to the plotter. 
- the last 2 from the gps antenna is not used at all.
- 2 of the cables from the plotter (nmea cable) is not used at all.

I have an idea about how to connect everything but don't know how to explain it in english... Confused


//Patrik
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#10
The only thing you can do at this point is to attach the NMEA output of your C80 to an RS422(or RS485 or RS232) USB interface on your PI or even to a laptop, configure in incoming serial port, and then use diagnostics to see what data is actually being sent out that port. As I said, my ST-60 display has an outgoing NMEA port, and I can see depth and magnetic heading coming out. I agree that the part about showing an RS232 interface in the installation manual is confusing - as you say they show nmea to a radio as via an RS232 converter. I don't understand why they don't show that connection as coming directly from the C80's NMEA port.

I looked at the C80 manual here: http://raymarinec80.com/wp-content/uploa...Manual.pdf

On page 186 there are instructions for "NMEA Output Setup" that allows filtering of the following sentences: APB, BWC, BWR, DBT, DPT, GGA, GLL, MTW, RMA, RMB, RMC, RSD, RTE, TTM, VHW, VLW, VTG, WPL, ZDA. That would indicate to me that if those sentences are not filtered, they are sent out that port. That is somewhat consistent with my ST-60, which sends out DBT and HDM sentences (those are the only sensors on my ST bus right now), both of which are created elsewhere on the Seatalk bus. Having said all that, I found that the NMEA sentences coming out of my ST-60 lacked checksums and complete information, which Openplotter didn't like even when I turned off the checksum requirement on the port. There's a discussion elsewhere on this forum about using Node-RED to add those checksums and the rest of the information. Again, this is a good reason for testing the stream coming out of the C80 first, before laying out the money for a protocol converter.
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