Autohelm 6000 nmea question...

dalex

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With good intent, I set out to buy a few 'essentials' from the local jumble today, and ended up with an Autohelm 6000 pilot!
I have the pump, 2 control heads, the main computer and the connection box. What I don't seem to have is something in the manual referred to, as the radio navigation interface.
I'd gotten hold of a flux gate compass and a rudder ref some while ago, although the manual doesn't show a rudder ref in the circuit.
The manual assumes you bought all the bits at the same time, and everything just plugs together.
What I am not so sure about, are:
1) do I really need the radio navigation interface box? Would the serial connectors in the main connection box take nmea183 straight from a GPS?
2) cutting into the hydraulic lines to the steering ram and connecting in the pump seems on the face of it straightforward with the correct high presure connectors, but how do I tell if I have a 2 line system, 3 line system or 3 line pressurised system of hydraulic steering? Boat is a 305 Statesman with 2 AD41's and DP outdrives.
3) once I have coupled up the pump to the hydraulic lines, is it a simple job to bleed the steering? I've not seen any info on how to actually bleed the system, and my ploy would be to fill the reservoir up to the maximum mark, crack the thumb-bolt at each steering station and wind the wheel from lock to lock till no air comes out. Is this how to do it?
Reading the manual, it seems to suggest that the pilot will know when the rudder is hard over, as the current draw rises. The pilot computer senses this and chops the power to the pump in that direction. I reckon this means no need for a rudder ref.
I am pretty competent at most things, but does the panel think this is akin to diy brain surgery and I should get the experts in to fit it? The book makes it all sound so easy!

Many thanks for any info you can divulge!
 
Have got this system on my boat with rudder indicator but sans the radio nav box.The boat was fitted with Decca and but previous owners had not bothered to connect with Decca/Loran etc.. My hydraulic drive unit is connected vis a couple of "T" pieces to the 2 pipes going to my steering ram.When we reburbished my steering ram recently,we bled the system from the ram end and it worked OK.If you have the full installation manual Fig 26 shows the different pipe configurations.The full manual is available as a a down load off the web.Think there are two different pump sizes mentioned depending on size of boat,up to 35ft and over 35ft.Happy to take a few pixs of offending items if will be of help,unable to help on Gps info but this exact subject was raised on Scuttlebutt? a few months ago and I lost interest and went back to trying to understand relativity theory as it was easier. /forums/images/graemlins/confused.gif
 
So what are the additional serial connectors for? Is this for the seatalk bus? If so, I have some details on the data strings, and could probably work out a conversion for nmea messages.
 
Have a look at Raymarine's web site. www.raymarine.com
They have a load of "retired" manuals you can simply download.
As Steverow says - what is the course computer?
Then find the manual - its all in there.

In answer to your first question, I suspect you need an NMEA bridge - again the manual is on the website.
 
Would be very interested to learn if a modern GPS could be made to talk to the Autohelm 6000,as would one or two others on here with similar systems.
 
Yes, it can be made to work with GPS

Some 3 years ago I posted the solution to the 6000 and GPS on this very forum.
It was however quite detailed so I will give a synopsis.

Of course the 6000 needs the Nav interface (model Z075), which originally took ONLY Cross Track Error info (XTE) from either Decca or Loran. However this was in the early NMEA format - 0180 & not the present one of 0183.
Modern GPS's give out multiple sentences, which include XTE. However compounding all that, the format for XTE has changed. Although the Nav interface sort of recognises the XTE sentence, the actual XTE data is too long.
So to solve this, I had a microprocessor based filter made, which looks for the XTE sentence, modifies it, then recourgitates in the format that the Nav interface understands. To arrive at the correct format I had to use a laptop configured as a terminal, and sending out XTE sentences in a loop till I got it to work.
The upshot of all this I now have a filter Made by Marin Electronik in Sweden, fitted between the GPS and the nav interface & hey presto the boat will steer a true course, and even go round corners, albeit a wide arc.
The device from Marin is called a Ferret 3 NMEA 0183 filter

There is however one word of caution. My filter was configured for the format that my GPS (Streamline) gave out, which supposedly met the NMEA O183 of 1995. There is the possibility that different models may be slightly different yet still conform to 0183.

The cost was around £135 I seem to remember. The E-prom in the filter can be adjusted to look for the XTE in any format, and give out precisely what the Nav interface requires, which is what I had to find out, as all this info has been archived in the cellars of Raymarine.

In practice, the Nav interface, increments the course computer by 1 deg increments ( Left or Right) intil the XTE is zero). For example I came back from St. Vaast to Portsmouth in a force 4, and my maximum XTE was 0.5 nm, not bad when you consider we were skewing all over the place.

So if anybody wants more detailed info, send me a PM.
 
Re: Yes, it can be made to work with GPS

[ QUOTE ]


So if anybody wants more detailed info, send me a PM.

[/ QUOTE ]
PM sent!
 
Re: Yes, it can be made to work with GPS

Thanks for the info you sent. Very useful. If anyone else is looking into this, the z075 is your man. The handbook wasnt available from Raymarine, but I found a copy of it here
The z075 should accept the complex nmea0183 XTE sentences but consult your GPS documentation for how this is achieved.
 
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