Pypilot with ST4000 autohelm

[Peter—]

Ironman, don’t go an burn your st2000. I can plug an 422 adapter into my raspberry or esp32 so I don’t need to use the tx gpios

Why do I need an isolated 422 when the raymarine nmea is isolated?

To satisfy my curiosity I'd burn anything ;-) curiosity leads to knowledge.

Haha - that is true and priceless advice.

I’ll run an ordinary rs422 to my raymarine for now and test how that works out. Will try to install it before new year.

As for the NMEA sentences, are they provided by OpenCPN in the correct format or do I have to reformat it for the raymarine using node-red? Just asking to try to save some time on this and avoiding reinventing the wheel by doing my own PID controller which I could see myself ending up doing if this is too tedious.. so help is much appreciated..

Br, Peter

Just dumping this data for a future reminder when I'm going to set it up:

Code:

NMEA data formats
TheST4000+ can decode the following NMEA 0183 navigation and
wind data:

Information NMEA 0183 data
Course Over Ground VTG, RMC, RMA
Speed Over Ground VTG, RMC, RMA
Cross Track Error APB, APA, RMB, XTE
Bearing to Waypoint APB, BWR, BWC, RMB
Distance to Waypoint BWR, BWC, RMB
Waypoint Number APB, APA, BWR, BWC, RMB
Apparent Wind Speed VWR, MWV
Apparent Wind Angle VWR, MWV
Speed Through Water VHW
Depth DBT
Water Temperature MTW

Note: The autopilot only decodes the last four characters of waypoint names.
This means that the last four characters of long waypoint names must be
unique for the waypoint advance function to work.

Transmitting NMEA data on SeaTalk
If the ST4000+ receives any of the NMEA data shown above, and the
equivalent data is not present on SeaTalk, it will transmit the data onto
SeaTalk to make it available to other SeaTalk instruments:
• the ST4000+ transmits depth information in the units defined by
the first page in the data page rollover
• the ST4000+ always transmits water temperature in °C . . .”

Source: NMEA GPS input to ST4000+ | YBW Forum

I hope the OpenCPN will spit these NMEA statements out. Otherwise I'll have to write a script that generates cross track errors etc..
Update: They are: https://opencpn.org/wiki/dokuwiki/doku.p..._autopilot

Br, Peter