[C320-list] How to get Raymarine Auto Helm to talk to a GarminChartplotter

[Graeme Clark]

Raymarine do a converter that converts old Seatalk to Seatalk NG which is different but compatible with NMEA2000 
I actually have one of these unused but guess it’s not a lot of good to you here on the other side of the Atlantic!
I also use the NGW1 to interface old NMEA0183 instrumentation with my new Raymarine EVO autopilot
The problem is that NMEA0183 works on a “one talker,many listeners” basis as there is no control of data sending. So as soon as you have a device like a chart plotter that can use multiple inputs, unless it has multiple NMEA input ports you’re stuck
NMEA2000 doesn’t have this problem so a modern plotter might only have a single NMEA2000 inoutvss this can handle multiple talkers
The solution is a multiplexer that combines the various NNEA0183 signals and transmits them in sequence
The analogy is that you have one clever person who can listen to three people talking at once and then repeat what they each said in one long sentence
I (with a lot of help from a friend) built a small Arduino processor based box of tricks that dies this
So we have NMEA0183 wind data, GPS data, depth data all multiplexed and output as one long string of data that is converted by the NGW1 to NMEA2000 format to be used by the EVO autopilot. 
In theory - but beyond our combined ability - the conversion to NMEA2000 could also have been done by the Arduino

Graeme
1996, #366


Sent from my phone. Excuse typos! 

> On 1 Oct 2019, at 23:45, Doug Treff <doug at treff.us> wrote:
> 
> If you're referring to the ST4000, it can be done but it's not straightforward. The old stuff used NMEA0183 protocol and different wiring. The new stuff uses NMEA2000. I wanted an integrated system that would steer GPS waypoints and wind angles so I replaced everything. Plus, you really don't want to be fooling with that wiring more than once. It sucks running wires up the guard tubes.
> 
> If you really want to keep the old AP, take a look at ActiSense NGW-1 (http://www.actisense.com/products/nmea-2000/ngw-1/ngw-1.html ) as a possible way to get the setup that you want. It looks like a pretty slick way of interfacing single NMEA0183 devices on a boat that is mostly converted to NMEA2000. 
> 
> I just didn't want to do the wiring job twice (The AP was getting pretty long in the tooth) so I ripped it all out for new gear.
> 
> --
> Doug Treff
> doug at treff.us
> 
>> On Tue, Oct 1, 2019, at 3:21 PM, Pat Tormey wrote:
>> Charles I have the Garman chartplotter with a Raymarine auto helm. Came 
>> that way so I don’t know the “how”
>> Lemme know if you need me to puzzle it out.
>> 
>> Pat
>> 
>> Pat Tormey 
>> s/v Blue Skies
>> 
>> From: Charles Martin
>> Sent: Tuesday, October 1, 2019 12:05 PM
>> To: C320-List at catalina320.com
>> Subject: [C320-list] How to get Raymarine Auto Helm to talk to a 
>> GarminChartplotter
>> 
>> Has anyone tried to connect the standard Raymarine Auto Helm (uses SeaTalk
>> comm) that was factory installed in C320's to communicate with a Garmin
>> Chartplotter?  If so, did you use some sort of cross-talk adapter?
>> 
>> Best,
>> Chip Martin
>> *Bonaventure*, Sail # 767
>> (410) 231-0199
>> chiprmartin at gmail.com
>> 
>>