Opencpn to Seatalk and SeatalkNG

[goodwinds]

Howdy All

I have a set of Autohelm ST50’s (depth, wind, compass, speed) through a ST-STNG converter to a P70s Autopilot.
I also run Opencpn on a MacBook with its own small GPS puck.
I understand there’s lots of NMEA0183 to 2000 converters, and USB to NMEA0183, and some to STNG even...

Outcome I’m after is:
GPS data from Opencpn GPS puck to output to pilot for track and SOG

ST50 data available on Opencpn (SPeed, Wind speed/direction/depth)

And any output from P70 that can be used on OpenCPN?

Possibly a few ways to do it, many Actisense or even Raymarine products.
Most I read have GPS on RAYMARINE network connected to Opencpn, not the other way.

Thoughts and ideas anyone? I have a spare ST-STNG converter or spare ports on STNG spurs.

Future is possibly installing a Raspberry PI and monitor instead on MacBook, but that’s way done the track..

[Tillsbury]

It's overkill for just that alone, but I had similar stuff and connected a Vesper XB8000 AIS unit. This takes all the ST/STng and transmits it over Wifi to any devices. It also sends the AIS back down STng if you have old chartplotters. OpenCPN on my Macbook now shows all info including AIS, and so does SeaIQ on iPad/iPhone.

[rgleason]

I believe the ST-STNG Converter converts both ways. If you have this connected properly to your ST bus then the STNG (aka Nmea2000) bus will have all instrument data.


I would use the Artisense NGW-1 to connect Opencpn (Nmea 0183) to your Nmea2000 bus, bidirectionally. This will bring your instrument data to Opencpn and also send your GPS puck data to the Nmea2000 bus when properly configured. If you have two GPS you can set priority or disable one.

See https://opencpn.org/wiki/dokuwiki/do..._---_nmea_2000


See the Panbo article in this link for wiring the STNG bus to an Nmea2000 bus. Panbo: “N2K, cable mixing not a big woop” by Ben Ellison and posted on Feb 5, 2008
https://opencpn.org/wiki/dokuwiki/do...k1_to_nmea2000

[goodwinds]

After more research I’m thinking of a Actisense NGW-1-USB with a STNG cable, and connect to STNG spur.
Still not sure if Opencpn GPS data will go to STNG, or if all data strings from ST50’s will appear on Opencpn.
It’s not a multiplexer, however if all data is on ST or STNG, I presume it should work.
Anyone have a similar setup?
I’ve heard that Opencpn doesn’t like sharing GPS data on a Computer, however would it output GPS data on NMEA0183?

Thanks
Shayne

[mikedefieslife]

I use the Can-USB module by the Openplotter guys. It works well. I have all the data I need into OpenCPN. No matter what I've tried I've still not got OpenCPN waypoint data to the Autopilot though despite checking everything in the manuals.

On the other hand I use the WilhelmSK app, with the same Can-USB adapter, and cant fully control the autopilot from my phone or ipad. Great for when sitting at the bow, chilling and wanting to change direction a little.

[boatbod]

I just installed a Yacht Devices (yachtd.com) N2K wifi router that has a bidirectional ST1 interface along with two NMEA0183 interfaces and a NMEA2000 connection. It's early days, but so far the autopilot is happy to accept waypoint data from my laptop opencpn whereas I was never able to make it work once the old Raytheon seatalk converter died.

[Moo]

Originally Posted by goodwinds

After more research I’m thinking of a Actisense NGW-1-USB with a STNG cable, and connect to STNG spur.
Still not sure if Opencpn GPS data will go to STNG, or if all data strings from ST50’s will appear on Opencpn.
It’s not a multiplexer, however if all data is on ST or STNG, I presume it should work.
Anyone have a similar setup?
I’ve heard that Opencpn doesn’t like sharing GPS data on a Computer, however would it output GPS data on NMEA0183?

Thanks
Shayne

You'll see all the data OK. With N2K (STng) you don't need to multiplex it in the way you are thinking of (as you do for ST and NMEA0183).



N2K is a bus with all data being available to all devices connected.



I think you are misusing the term GPS data. GPS data is position derived from GPS satellites. The data that you are talking about for the AP etc.. is just well data... course to steer, etc...



Chris

[goodwinds]

Thanks Chris, you are right, basically looking for SOG which will come from GPS and not paddle wheel into Opencpn, then hopefully output from NGW-1- USB back into the STNG bus onto P70.
I also just setup a Raspberry PI with Openplotter/opencpn, also hopefully the NGW1-USB works.
Strange thing with ST-STNG converter, all data seems fine, however wind direction on P70 can be 180 degrees out, then others times close to ST50 reading, basically all over the place, so using Vane mode is impossible. Data is data, can’t understand why 1 string would be so random

[Moo]

Originally Posted by goodwinds

Thanks Chris, you are right, basically looking for SOG which will come from GPS and not paddle wheel into Opencpn, then hopefully output from NGW-1- USB back into the STNG bus onto P70.
I also just setup a Raspberry PI with Openplotter/opencpn, also hopefully the NGW1-USB works.
Strange thing with ST-STNG converter, all data seems fine, however wind direction on P70 can be 180 degrees out, then others times close to ST50 reading, basically all over the place, so using Vane mode is impossible. Data is data, can’t understand why 1 string would be so random

I can confirm that NGW works with a PI


A couple of things to check on the P70:


When you say wind; are you referring to True Wind Direction (TWD) Ground Wind Direction (GWD) or Apparent AWD? Which is on ST50 and which on P70?



TWD (Which is actually only true to the surface of the water as current isn't accounted for) requires AWD, Course over Ground (COG), and Speed over Ground (SOG) and they need to be fairly stable. Ideally HDG (Heading) as well but you can select COG to be used instead.



They real true wind (Ground wind) requires Speed through the Water (STW), HDG and ideally leeway. As well as some of the above.



So if you don't have all of the correct data configured and boat speed etc. accurately calibrated then your wind readings will be off. It could just be an instrument calibration issue where repeated tweaks have messed things up.



If I was setting up your system I would make sure that I had a good set of clean data and wipe the instruments back to factory reset and run all the calibration routines again, by the book with no shortcuts.


Cheers
Chris

[goodwinds]

Really good points Chris.

My ST50 wind speed/direction doesn’t have the True/Apparent button, so I always presumed it was apparent as when going downwind wind speed drops and seems a calculation of True wind minus STW. The system has HDG from ST50 compass, but I haven’t seen an effect from that.

I’ll need to check the P70 to see if it’s the TWD, GWD or AWD, however the ST50 vane direction (not sure if AWD or TWD always seems close the manual vane on the mast so again presume it’s AWD. But the P70 can show similar sometimes, or it can show 180degrees off, I could be close hauled at 45degrees, and the P70 showing wind angle from behind like I’m going direct down wind.

Agree, time to get all the manuals and factory reset. I just thought the potentiometer/encoder type thing on wind vane must give a direction signal, and that signal would have been the same on P70?? If one wrong both would be wrong??

Once I’ve got the NGW1, then I’ll have COG and SOG to help things out.
Yes, I’ve played and tweeted with the ST50 wind cal +\- buttons a bit, but never really followed instructions... just moved it till it matched the manual vane.
Thanks for the suggestions

[Moo]

Originally Posted by goodwinds

Once I’ve got the NGW1, then I’ll have COG and SOG to help things out.
Yes, I’ve played and tweeted with the ST50 wind cal +\- buttons a bit, but never really followed instructions... just moved it till it matched the manual vane.
Thanks for the suggestions

I think you are right about the ST50 it is Apparent only.



The calibration on Raymarine wind instruments is always tricky IMO. But to partially answer your question about how the displays can be different. I am presuming here that the wind transducer is connect to the ST50 wind instrument? Then that instrument, or which ever is actually connected, will decode the signals from the masthead transducer (sine signals for one 0 - 180 one side and cosine signals the other - well sort of ). It then puts out an apparent wind onto the ST bus.



The P70 takes that ST data and combines it with other data and it's own internal calibration (this will include the windspeed input so if that is out of cal it will give wind direction errors too) to produce its own version.


Anyway it is all smoke and mirrors but if any steps are performed out of sequence then errors can creep in that can cause what you describe.



Would love a $ for each circle I have done helping my clients go through the calibration routines.



Do you have the evo version of autopilot down below on the brains of the pilot - the thing that looks like a little white UFO? Or are you still using a version with a fluxgate compass (black hockey puck mounted vertically somewhere)?



Anyway this is somewhat off topic for this forumn but if you want my opinion once you get set up further on down the track when you have everything setup feel free to PM me and I'll try to get back to you .



Chris

[goodwinds]

Yep, Evo 100, the new style brain that apparently is the business!
Didn’t help that I mounted it next to the Fluxgate compass of the ST50 Compass.... I will give them more room... not sure how many magnets are in either.
Appreciate your help, once she’s back in the water (standing rigging, antifoul and new strips) and all connected with NMEA converter I’ll PM. It’s a great learning, almost know every wire, and square inch of her now... just weird when the new P70 disagrees with the wind direction... the funny side is when I put the P70 in vane mode, and did a auto tack, she did a 360 degree turn before I went back to Standby and gained control....some strange looks by the peanut gallery on the shore line...
Cheers, appreciated heaps

[goodwinds]

OK, finally got Actisense NGW-1 USB. Sitting on boat today and plugged in to STNG via adapter cable, 1 LED on STNG side flashing.
Open Opencpn, go to connections, add new connetion nad it shows no new device?
Macbook - System Report - USB show NGW-1???
Download NGW-1 Driver for MAC OS X USB, install in Mac, and again nothing in Serial Dataport in Opencpn, it says to manually type in, however new to Mac's so don't know what to type in manually.
Or any other suggestion how to get Opencpn on Macbook to see Actisense in Connections/Dataport?
Cheers
Goodwinds

[goodwinds]

Out of interest, I plugged the Actisence into my Raspberry PI /Openlotter/Opencpn...
It saw it straight away, can't confirm data yet as only have the Actisense at home, no NMEA data... Is there any way to activate USB drivers on a Macbook?? Or am I doing something wrong?

[SCarns]

Originally Posted by goodwinds

Out of interest, I plugged the Actisence into my Raspberry PI /Openlotter/Opencpn...
It saw it straight away, can't confirm data yet as only have the Actisense at home, no NMEA data... Is there any way to activate USB drivers on a Macbook?? Or am I doing something wrong?

I don't think you're doing anything wrong. Somewhere along the way, Apple changed the way they handle USB drivers and the FTDI driver that many of these devices use get confused. For example, my USGlobalSat GPS puck works great on my MacBook Pro, but my DigitalYachts USB->NMEA 0183 adapter doesn't even show up. I haven't been able to work it out yet. However, there is an Actisense NGW-1 USB to STNG converter in my near future, as I just bought a boat with a complete (but slightly dated) Raymarine system on it and desperately want OpenCPN to be running overtop of the whole thing.

Perhaps there's another Mac somewhere you can plug the USB side into to see if it's just your machine or if it may be something else?