Opencpn - nmea sentence generator

[skipperearly]

Forgot: have also the artisense with different adaptors in case I get easy access to the on-board nmea network. Total investment less than 💶 300!

[katoema]

Originally Posted by skipperearly

I use openplotter on rpc3...

I'm running a W10 laptop on passage, using Open CPN, thus a different setup.

It is not a plotter I'm seeking, but a method to capture a vessel's NMEA data and utilise Open CPN's different plug-ins.

AIS, for example, not many owners are prepared to buy it and those that do, the majority just get receive. However, having the ability to collect a vessel's data on Open CPN is a bonus!

Thanks...

[Paul Elliott]

If you just want sample NMEA capture files, I have a couple on my NavMonPc site that I saved from two Pacific Cup race starts. Here's a link to the "Downloads" page: NavMonPc

These contain all my nav data including received AIS. The format is NMEA-0183. I captured them with NavMonPc, and I think OpenCPN will play them back. If not, you can use NavMonPc to play these files and feed the NMEA data to OpenCPN via a virtual serial port or the NavMonPc TCP/IP server.

[katoema]

Hi Paul,

Just looked at the page and I understand what data is being presented. However, it is how is the raw data captured that has me foxed. I have the laptop, I have Open CPN, I am on a vessel - now, how's that data getting to my laptop without any interference with the owner's vessel?

What cables/connectors do I require to go from my laptop to (a) the vessel and (b) the different instruments that may be on board?

As I mentioned, it will be on different vessels.

Thanks

[Paul Elliott]

Originally Posted by katoema

Hi Paul,

Just looked at the page and I understand what data is being presented. However, it is how is the raw data captured that has me foxed. I have the laptop, I have Open CPN, I am on a vessel - now, how's that data getting to my laptop without any interference with the owner's vessel?

What cables/connectors do I require to go from my laptop to (a) the vessel and (b) the different instruments that may be on board?

As I mentioned, it will be on different vessels.

Thanks

Ah, I misunderstood. You want to send the nav data being generated by a boat's instruments to OpenCPN on your laptop. In doing this you don't want to disrupt the boat's existing system.

Doing this will depend on the nav gear aboard. Some nav equipment includes a built-in WiFi port. If so, you should be able to connect with little fuss. This WiFi connection may not include all the data you are looking for, this depends on how the nav gear is interconnected.

There may be a NMEA multiplexer that you can access. Again, the data available will depend on the multiplexer's connectivity and configuration.

Perhaps there is a chartplotter with an NMEA output you can use. If there isn't a spare port, you can usually bridge the INPUT of an RS232 (or RS422) adapter to existing NMEA connections at the chartplotter output port. One NMEA output can drive multiple NMEA inputs.

A NMEA-2000 nav network will require a specific adaptor, and a place to connect it. I believe that OpenCPN will interface to an Actisense USB/N2K adaptor but I haven't tried this myself. Perhaps someone here can advise you on that.

[katoema]

Originally Posted by Paul Elliott

Ah, I misunderstood. You want to send the nav data being generated by a boat's instruments to OpenCPN on your laptop. In doing this you don't want to disrupt the boat's existing system.

Yes, that's exactly it!

I'll research around your information and see what I need.

Away for a few days now on Skye and plenty time to read

Thanks

[Pizzazz]

As Paul said, the easiest is to get a USB to serial port adapter with two serial ports. Then you can use Python (or another app but Python is standard with lots of examples on the web) to read and manipulate the data.

If you want to make sure that your boat network still operates without the PC switched on, then you should only read the data and have the input and output ports physically connected (can use a double pole switch). It is really just $20 bucks for the USB to serial adapter and a couple hours with Python.

[conachair]

Originally Posted by katoema

I'm running a W10 laptop on passage, using Open CPN, thus a different setup.

It is not a plotter I'm seeking, but a method to capture a vessel's NMEA data and utilise Open CPN's different plug-ins.

AIS, for example, not many owners are prepared to buy it and those that do, the majority just get receive. However, having the ability to collect a vessel's data on Open CPN is a bonus!

Thanks...

So just to clarify - do you want to get your laptop receiving NMEA data from a boat(s) you are delivering?
Difficult question to answer as every boat is different..
If there is NMEA0183 already multiplexed then you could just plug that into your machine with a usb/serial cable. NMEA2000 probably more expensive but no doubt achievable, I've never played with 2000.
But every boat will have its own system so there isn't really a plug and play answer to your situation.

[katoema]

Originally Posted by conachair

So just to clarify - do you want to get your laptop receiving NMEA data from a boat(s) you are delivering?

Yes, that's about it. The issue is that all boat's are set up differently with their equipment.

I think, therefore, from what you are saying and also that of Paul is that I need to get a connector (s) (a) from my laptop, it has to be USB as there are no other places, but the cable needs an adaptor or two on the other end. And (b) it has to cater for whatever instrumentation is on the boat.

"NMEA0183 already multiplexed". I know that '0183' was and is the standard for older boats, but how is that multiplexed to fit on to the cable that then plugs into my laptop by USB? Am I missing something here?

Thanks

[Paul Elliott]

An NMEA multiplexer takes multiple NMEA data connections to and from your various pieces of nav equipment. It receives them, combines them (sometimes picking and choosing particular data messages from various ports), and sends this combined data stream to the inputs of your nav gear. The multiplexer will have several inputs, and outputs, sometimes with different formats, but usually NMEA0183. Some multiplexers have a one or more serial / USB / WiFi / Bluetooth ports for connection to a computer.

I have the Miniplex-3USB, and it works well (ShipModul Maritieme Elektronica). There are other brands. The multiplexer isn't the only way to skin this cat, but it's pretty common.

[katoema]

Paul, one last question this evening. Looking at the multiplexer, which receives differing data, will there be one "spot" on the boat to collect all this from, or have I physically got to make connections to different instruments?

Mentioned earlier was that there should be a take off from a plotter, etc. If this is the case, what type of connector will be required to fit the 'plotter' and does this then fit in to the multiplexer?

Thanks

[Paul Elliott]

Originally Posted by katoema

Paul, one last question this evening. Looking at the multiplexer, which receives differing data, will there be one "spot" on the boat to collect all this from, or have I physically got to make connections to different instruments?

Mentioned earlier was that there should be a take off from a plotter, etc. If this is the case, what type of connector will be required to fit the 'plotter' and does this then fit in to the multiplexer?

Thanks

Many instruments are interconnected, often via a multiplexer. There may be one convenient spot where you can grab this data. Other instruments may not be connected to anything else. You may or may not be able to find a way to get that data.

The data output of a chartplotter (NMEA0183 or NMEA2000) will be via some sort of connector. N2K is fairly standard (but not always), and the NMEA0183 ports vary wildly. There may be an available connector, or perhaps some wires leaving the chartplotter.

If you are lucky, the data you want will be interconnected on a terminal strip somewhere, and perhaps you can connect there. If you are really lucky there will be a WiFi port on the chartplotter or other well-connected bit of gear.

Sorry I can't be more specific, but it truly is this confused. The data formats are pretty well standardized, but the physical connections? Not so much.

[katoema]

Paul, thank you the additional information and, yes, the complexities of different vessels give my task a downside For now Open CPN provides via my USB GPS for speed, course, LatLon position. If I can manage depth and AIS, then I have all the data I require

Off tomorrow to Skye for a break after a hectic year of deliveries. New transatlantic season coming up. Take Care. Martin

[rgleason]

What Manfacturer and Model are your Instruments?
AIS
Depth etc.
What is the data bus used by your Chartplotter?
Some are proprietary some not.
Nmea 0183
Nmea2000
Seatalk (Raymarine early)
-- For example here is what I use for my Raymarine ST60 instruments Tiny Seatalk Nema0183 Link with Galvanic Isolation
STns (basically Nmea2000 with different connectors)
etc..

Suggest you find out the data bus and format used and then look up Artisense because they have converters that are useful for Nmea2000 and Nmea0183.
http://www.actisense.com/product/ngw-1/
USB http://www.actisense.com/range/nmea-0183/
USB http://www.actisense.com/range/nmea-2000/

Raymarine also has a converter for nmea O183 bidirectional with 2000.

Depending on your system configuration you may need a converter.