Electronics.. NM0183 to SeaTalk prob..

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LeonF

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Have a ST4000 tiller pilot & controller which also acts as a repeater from my Simrad CP33 chart plotter which is in the cabin. Over a year ago it started to fail to transmit SOG to the controller, and was showing Sea Talk failure, so sent the interface box back to Raymarine who charged me about £50, said they upgraded the software, gave me a six month guarantee, and it worked. Now it's doing the same, but with no Seatalk failure warning. It will input Seatalk data to the chart plotter, depth data shows on the chartplotter, but no output will repeat. Alll shown on the plotter so I know that's functioning. Have checked the connectors, though may have to do so again, but wondered if any of you boffins have any suggestions ?
 
LeonF said:
It will input Seatalk data to the chart plotter, depth data shows on the chartplotter, but no output will repeat.
Click to expand...

I'm not sure I understand this sentence.

AFAIK the NMEA output of the autpilot only sends/repeats out only a limited set of information present on the SeaTalk bus. But if you say the plotter shows the depth, but not the Speed Over Ground then I suspect the connection between the GPS instrument and the Autopilot is faulty. Can you steer to a waypoint (set on the GPS) on the Autopilot? If no then I'd expect the connection between the GPS and the Autopilot (that may very well be daisychained via other SeaTalk instruments) is broken. If that is OK then it may be a setting on the plotter that was altered.

This is based on the assumption that the plotter has no GPS of it's own, because then it would determine the SOG for itself.

Or are you talking about STW?
 
#2 Today, 16:11
aluijten
Registered User Join Date: Oct 2004
Location: Dordrecht, The Netherlands
Posts: 658



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Quote:
Originally Posted by LeonF
It will input Seatalk data to the chart plotter, depth data shows on the chartplotter, but no output will repeat.


What I was trying to say was that the plotter, that has it's own GPS, will receive info via the SEATALK bus, converted to 0183. So on the plotter I can see depth, wind. The plotter is showing SOG, BTW,DTW. The last sets of info is what is not being transmitted to the repeater via the SEATALK bus. I spoke to Raymarine, and they said it might be a faulty SEATALK cable.
 
Leon -

On mine, you can take NMEA directly from the GPS to the ST4000 head - ie any old 2 core wire. Doesn't sound as though yours is like this. If so, is it possible to try it? It might then tell you whether the info is being transmitted in the first place properly. If it would help to wire it up to a different control head to rule it out then you are more than welcome to come down to Gillingham.
 
What I was trying to say was that the plotter, that has it's own GPS, will receive info via the SEATALK bus, converted to 0183. So on the plotter I can see depth, wind. The plotter is showing SOG, BTW,DTW. The last sets of info is what is not being transmitted to the repeater via the SEATALK bus. I spoke to Raymarine, and they said it might be a faulty SEATALK cable.
Click to expand...

So if I understand you correct, you expect to see the SOG (a piece of information derived by a GPS receiver) transmitted from the Plotter (that has the GPS connected) to the Autopilot.
From the Autopilot the data is then converted to the Seatalk bus.
Is this correct.

If yes then the cable between the Autopilot and the rest of the Seatalk instrument could be faulty. You could check this by setting/activating a waypoint on the plotter and see whether the Autpilot is able to steer to this waypoint. If yes then the communication from the plotter to the autopilot is OK.

If you have a second GPS receiver in the Seatalk bus, this may also be the cause of the problem.
 
Thanks Pye...I'll explore and get in touch if I need to. I didn't think that one could input 0NMEA straight into a Raymarine instrument, I thought it always had to be converted to Seatalk.

Aluijten. The NMEA goes from to the plotter to the Seatalk bus and then to the autohelm (as I undertsand it). But I can try your suggestion and see if just trying to get the autohelm to steer to a waypoint thats is present on the plotter, but not on the repeater, works.
 
Just had another bash at the problem, the fault was still intermittent. Tinned the ends of wires into the Seatalk box for a better connection, no result. Corrosion was the problem, the NMEA cables that run from the plotter to the Seatalk box had a badly corroded join under the port berth. Now to make a really good moisture proof join..
 
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