NMEA 2000 Rudder angle output Destination

[gilbertpark]

I am trying to install the New Humphree Lightening stabiliser system. The NMEA 2K system is defeating me!

I have a Raymarine Seatalk (ST) system which has a ST6001 head and a 150 controller. This works fine. The ST system is connected through a Raymarine Seatalk to Seatalkng converter to the NMEA 2K system using Raymarine's Backbone system.

All of the ST instruments, including rudder angle display on my raymarine Axiom Pro.

The Rudder Angle is not shown on the NMEA 2000 Lightening control head, so nothing works properly.

The screenshot of the NMEA output shows the PCG 127245 is the correct sentence but the Destination 255 should be 251.

Does any one know how to get around the Destination problem? The easiest but most expensive option id to install a new autopilot!

Gilbert

 

[gilbertpark]

Unfortunately despite resizing the JPEGs to 50kb they still won't load!

 

[twistedtree]

255 is generally the correct destination address, and it the "broadcast" address. This is how 90% of N2K messages work. Devices that have data to send, sent it to the broadcast address of 255. Other devices wanting to receive data listen to broadcast messages and pick out the ones they care about. There are only a few N2K messages that are unicast (sent to a specific device) rather than broadcast.


Is 251 the address of the Humphries device?


I take it you have something to view PGNs on the N2K network? What is the Data Instance value in the Rudder PGN (127245)? I'm guessing it's 0xff, or 255 decimal. This has been a compatibility issue with N2K for at least 15 years. A data instance of 0xff means "not used", and that has been interpreted differently by different vendors. Some take it to mean "I don't provide a data instance number, so always use this PGN", where others interpret it as "This is not a valid data instance, so ignore this PGN". The interpretations lead to very different results.


The other possibility is that the data instance is some other number, and the Humphree device is looking for a different value. If a device is sending rudder info for a single rudder, it's supposed to use data instance 0, so that's what it should be.

 

[heysteve]

My guess is that a sentence with destination 255 is a broadcast to any interested device. After all, the rudder angle sensor doesn't know who wants the angle information. Why the autopilot is ignoring the sentence is probably a question for Humphree.

 

[Iggy]

One thing that puzzles me. You talk about a "Seatalkng converter to the NMEA 2K system".

On my last boat and some friends that have Seatalk. I installed a cable adapter. I never heard of a converter. You just need a cable adapter since the connectors between the two are not the same.

Is the converter a piece of hardware or a cable adapter?

 

[gilbertpark]

Hi Iggy

It's definitely a converter specifically designed to convert SeaTalk 1 to Seatalk ng if you Goggle it you'll find it. I think (I'm not an expert hence the post) just using the cable won't give full functionality.

Gilbert

 

[Iggy]

Hi Iggy

It's definitely a converter specifically designed to convert SeaTalk 1 to Seatalk ng if you Goggle it you'll find it. I think (I'm not an expert hence the post) just using the cable won't give full functionality.

Gilbert

Oh, I though it was Seatalk to NMEA2k.

 

[gilbertpark]

Hi Iggy

My understanding is that SeaTalkng is N2K with different plugs on.

G

 

[Iggy]

Yes. But you mentioned seatalk to Seatalk ng. Ng I have no experience with.

 

[Jeff F]

Yes. But you mentioned seatalk to Seatalk ng. Ng I have no experience with.

I think your experience is with NG only. The OP's old AP predates NG/N2k, hence the need for a converter.

It sounds like Humphree wants the OP to use their hardware. It is critical input data, so maybe their discrimination of the source is understandable.

 

[boomerang]

I am displaying rudder angle from a Raymarine autopilot system (ST 6001 control heads) using a seaTalk to SeaTalkng converter and then from that, using a seatalkNG to nmea2000 adapter cable, into the nmea 2000 buss where a Maretron NMEA2000 display shows the data selected. The only difference I see in your autopilot and mine is that I'm using a slightly later model S1 corepack and you're using a 150, which predates the S1 by a few years. No help but just an observation.

 

[gilbertpark]

Thanks for all the replies. I have solved the problem by putting an additional rudder angle sensor that is just plugged into the N2K system

Gilbert

 

[EngNate]

Problem may have been the converter not recognizing the particular PGN. These devices decode, translate and recode, not a simple conversion of data format. So they only work with the PGNs they are programmed for. Each device has a list of the data it will convert.