Send NMEA from OpenCPN to S2G autopilot Help

[otisploggerhead]

I am using version 5.6.0. on a Dell Inspiron core I7 processor, and am trying to send NMEA route info to a Raymarine S2G autopilot. I have a USB to RS422 converter cable. OpenCPN is sending all the correct sentences in the NEMA debug window, but the S2G does not recognize them. The cable appears to be working correctly as I checked at the input to the S2G with an LED. I tried all NEMA input locations on S2G.

[Hakan]

A few simple tests:
Check baud rate to be equal in both ends.
Did you used the out, TX, from the PC and input, RX/arrow up, on the AP.
Switch +/- connections in one end of the signal wire.
Do you need to set input ports on the AP settings?

[SamH]

When you have tested and verified all connections and stuff as Hakan suggests, youll have to deal with a v5.6.0-2 bug in the creation of the RMB sentence for the S2G autopilot to work with routeinfo sent from OpenCPN.

Workaround in this thread:
https://www.cruisersforum.com/forums...nt-265606.html

[otisploggerhead]

I think my problem is I am sending to many sentences to the S2G. A note on Raymarine's forum is to only send ECRMB to the autopilot, it has all the data required to navigate. NEMA input to S2G is supposed to be 4800. I have done all your suggestions, everything as you state. Unfortunately I am 200 miles from my boat right now. Thanks for your suggestions, it is much appreciated.

[Hakan]

Sounds strange but one good habit could be to filter the output connection to only send "EC". That's all AP related messages from route manager, "ECXTE, ECRMC ..."

[otisploggerhead]

I am going to try sending only ECRMB when I get back to the boat. Gads I hope that works. Plus I just installed V5.6.2.
Thanks

[Hakan]

Late thoughts: If you happened to send out all you get from all sources like all GNSS, heading and maybe AIS the baud rate 4800 will choke and send nothing.
But all ECxxx will be fine on bandwidth 4800.

[otisploggerhead]

One other thing Raymarine says it expects mag direction, it looks like RMB is sending true direction. How do I make it send mag direction?

[Hakan]

If so Raymarine didn't read the NMEA0183 standards. Bearing true is stated:
https://gpsd.gitlab.io/gpsd/NMEA.htm...on_information

[otisploggerhead]

I saw that and of course was a bit confused. Here is what Raymarine says
BTW = Bearing to Waypoint
DTW = Distance to Waypoint
WPID = Waypoint ID (AKA = waypoint number)
XTE = Cross Track Error

Additional Note: Any Bearings need to be magnetic (preferred); otherwise, the autopilot must receive true bearings with variation in order to permit the autopilot convert the true bearings to magnetic bearings.

The RMB NMEA 0183 sentence contains BTW, DTW, WPID and XTE all in one sentence. As such, the autopilot will support tracking when this single NMEA 0183 sentence is received, as long as the included bearings are Magnetic as indicated above.

[Tehani]

I've run into that problem before: Replace the Ocpn talker "EC" with "GP".
The autopilot needs an incoming NMEA0183 connection at 4800 baud as you have been told.

If a GPS is connected via seatalk (Raystar for example), set Ocpn to send only GPRMB and GPXTE. Add GPRMC to the Ocpn output if the GPS data does not reach the pilot otherwise.

- Don't worry, RMB always uses true angles.
- RMC includes the Magnetic Variation.
- There is a reported problem with version 5.6.2 and RMB. It seems that it inverts the origin and destination waypoint numbers of the leg, but the symptoms are different.

J.L.

[otisploggerhead]

I use a BU-35364 USB gps for location input to OpnCPN. These data are then output in RMB. Using the debugger output info the ECRMB output from OpnCPN has all the correct info. Waypoint numbers are listed correctly in RMB output.
Thanks

[Tehani]

Originally Posted by otisploggerhead

I use a BU-35364 USB gps for location input to OpnCPN. These data are then output in RMB. Using the debugger output info the ECRMB output from OpnCPN has all the correct info. Waypoint numbers are listed correctly in RMB output.
Thanks

Just change the talker:
ECRMB by GPRMB
ECXTE by GPXTE
ECRMC by GPRMB

[otisploggerhead]

I'll try that, thanks
The talker seems to be sending correct data, the S2G doesn't seem to be receiving it. I an sending TX+ and TX- and connected to S2G NEMA input + and - location. Should work. I have three NEMA input locations available to me, tried all three. No success.

[pa391as]

how do you know the AP isn’t receiving?
what indication are you seeing ?