NMEA 0183

Thanks to everyone. If I follow the instructions supplied with the plotter and st60 then it seems like what I'm trying to do is possible, as PVB says, but then we have some other real world examples here that imply otherwise. Having now been able to download the st60 Raymarine manual it certainly suggests it will allow NMEA wind data out, but maybe it's the garmin device that won't accept it. I do also have the st4000 pilot that has the separate display and that has wind data so maybe I can get the data from that (but again maybe the same garmin restriction will apply). I must admit making a seatalk to NMEA converter would be beyond me, so maybe I'll try connecting it as PVB suggests, but with the expectation that I'll ultimately need to get some kind of converter. Maybe this is garmins way of trying to encourage people to use the garmin wind instrument. The garmin has a nice instrument dashboard feature and the lay lines functionality, so I would like to persevere and get the wind data to it. I may try and call them later in the week

Thanks everyone

Matt
 
pvb said:
It would be worth investigating how the GPS data is getting in to your SeaTalk network, there may already be some sort of converter installed which could be useful to you.
Click to expand...

That's no problem at all. The ST60 multi (or graphic) NMEA input will accept the Garmin output, no converter needed.
 
matt1 said:
Thanks to everyone. If I follow the instructions supplied with the plotter and st60 then it seems like what I'm trying to do is possible, as PVB says, but then we have some other real world examples here that imply otherwise. Having now been able to download the st60 Raymarine manual it certainly suggests it will allow NMEA wind data out, but maybe it's the garmin device that won't accept it. I do also have the st4000 pilot that has the separate display and that has wind data so maybe I can get the data from that (but again maybe the same garmin restriction will apply). I must admit making a seatalk to NMEA converter would be beyond me, so maybe I'll try connecting it as PVB suggests, but with the expectation that I'll ultimately need to get some kind of converter. Maybe this is garmins way of trying to encourage people to use the garmin wind instrument. The garmin has a nice instrument dashboard feature and the lay lines functionality, so I would like to persevere and get the wind data to it. I may try and call them later in the week

Thanks everyone

Matt
Click to expand...

Good luck, I spoke to both Raymarine and Garmin and got no help at all.

You can't get NMEA out of the ST4000. It takes it in and puts it onto the Seatalk bus, but has no NMEA out. you can only get it from the multi or graphic - which do you have?

The converter you need is dead simple. Can you solder a few bits together? I'll give you the bits and instructions if you can solder it up to settle this, I've got some spares! That's after you've tried the other suggestions and found they don't work!

it's worth doing, it's a nice display to play with on the Garmin! It was on the 750 anyway.
 
Plevier said:
Good luck, I spoke to both Raymarine and Garmin and got no help at all.

You can't get NMEA out of the ST4000. It takes it in and puts it onto the Seatalk bus, but has no NMEA out. you can only get it from the multi or graphic - which do you have?

The converter you need is dead simple. Can you solder a few bits together? I'll give you the bits and instructions if you can solder it up to settle this, I've got some spares! That's after you've tried the other suggestions and found they don't work!

it's worth doing, it's a nice display to play with on the Garmin! It was on the 750 anyway.
Click to expand...
Do you have this available as a circuit diagram with components ?

Thanks.
 
Plevier said:
Good luck, I spoke to both Raymarine and Garmin and got no help at all.

You can't get NMEA out of the ST4000. It takes it in and puts it onto the Seatalk bus, but has no NMEA out. you can only get it from the multi or graphic - which do you have?

The converter you need is dead simple. Can you solder a few bits together? I'll give you the bits and instructions if you can solder it up to settle this, I've got some spares! That's after you've tried the other suggestions and found they don't work!

it's worth doing, it's a nice display to play with on the Garmin! It was on the 750 anyway.
Click to expand...

Thanks - Its the ST60 Graphic and I take back my earlier comment about the ST60 wind manual providing NMEA out as I now realise I was looking at the Graphic instructions, which does appear to provide NMEA out. I have a graphic at the chart table and one also on deck. The one on deck will need to be removed to make way for the plotter!
 
superheat6k said:
Do you have this available as a circuit diagram with components ?

Thanks.
Click to expand...

Here is my very simple one that worked OK.
You can see Nigel Mercier's much more sophisticated one with various options in the thread linked earlier.
I did it a way that must make him shudder, fastidious as he is; I soldered the components together, potted them inside a bit of sleeving and stuck it to the back of the ST60. Two wires to the ST60 NMEA out tags, one wire to the Garmin NMEA IN +.
My circuit does defeat the isolation potentially provided by the opto-isolator, but isolation was not the object of the exercise.

attachment.php
Just noticed a minor error. It should of course show a link to power ground from the bottom of the ST60.
 
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matt1 said:
Thanks - Its the ST60 Graphic and I take back my earlier comment about the ST60 wind manual providing NMEA out as I now realise I was looking at the Graphic instructions, which does appear to provide NMEA out. I have a graphic at the chart table and one also on deck. The one on deck will need to be removed to make way for the plotter!
Click to expand...

I had a graphic and a multi. Officially their outputs are the same. In fact I couldn't get any NMEA output of any sort from my graphic - checking with an LED showed no signals - so I took the output from the multi instead and just assumed the graphic (bought used off the forum) was faulty which didn't really matter to me.
However I subsequently heard of someone else who couldn't get an NMEA output from a graphic.
I suggest that after checking your unit is set to NMEA out not alarm out (I'm sure you have but just in case!), put a small LED across the NMEA out tags and see if it gives bursts of flashes.
 
But I will still need to make up the above gadget even if I can get NMEA out the graphic? I've got wind data on the graphic, presumably over the seatalk bus?
 
matt1 said:
But I will still need to make up the above gadget even if I can get NMEA out the graphic? I've got wind data on the graphic, presumably over the seatalk bus?
Click to expand...

Correct on both.
It's a problem of Raymarine and Garmin both cutting corners and ending up incompatible.
If you had a chartplotter with a differential input as it should to to be fully compliant with the current version of NMEA standard it would work with the ST60, even though the ST60's NMEA output doesn't comply with the standard as regards voltage levels.
Unfortunately Garmin save themselves a few cents by not complying with the current standard. It's crazy.
What my - or Nigel's - interface does in effect is to give the Garmin the differential input that the standard says it should have to start with!

BTW if you have an analogue voltmeter you could check with that instead of an LED. The needle will flicker around, mostly near 11V but dropping in bursts. No good with a digital meter you'll just see nonsense.
 
Apologies if you already know this:
Most AIS receivers (all Mcmurdos included, I think) have an NMEA input. They multiplex data received on this (at 4800bps) with their own AIS data and transmit it (at 34,800bps) on their NMEA output.

You could connect the ST60 NMEA out (maybe using the opto-isolator circuit previously described) to the AIS i/p and then connect the AIS o/p to the plotter. Set the plotter i/p to work at 34,800bps.

Whether or not you need that circuit to convert from Raymarine's oddball version of NMEA depends on the design of the AIS i/p circuit. If this is already opto-isolated then it could well work without it.
 
Danny said:
Apologies if you already know this:
Most AIS receivers (all Mcmurdos included, I think) have an NMEA input. They multiplex data received on this (at 4800bps) with their own AIS data and transmit it (at 34,800bps) on their NMEA output.

You could connect the ST60 NMEA out (maybe using the opto-isolator circuit previously described) to the AIS i/p and then connect the AIS o/p to the plotter. Set the plotter i/p to work at 34,800bps.

Whether or not you need that circuit to convert from Raymarine's oddball version of NMEA depends on the design of the AIS i/p circuit. If this is already opto-isolated then it could well work without it.
Click to expand...

That could be a very good solution.
Just had a quick glance at the manual for one of the McMurdo units - it has 2 wires for NMEA in, not using the power -ve, so it would appear to be a proper differential input and should work with the ST60 without extra interfacing :)
 
Plevier said:
That could be a very good solution.
Just had a quick glance at the manual for one of the McMurdo units - it has 2 wires for NMEA in, not using the power -ve, so it would appear to be a proper differential input and should work with the ST60 without extra interfacing :)
Click to expand...

Wow! The power of the forum. I haven't bought the McMurdo yet, but that will be the next step. I'll let you know how it goes. Thanks to everyone who contributed
 
As Plevier says, the McMurdo AIS has a differential input. It also has a differential output of course - which doesn't match the Garmin implementation of NMEA either! I don't think it'll be a problem though. There are examples in the McMurdo user guides on how to connect their differential outputs to devices with single ended inputs.
 
It's not just the McMurdo of course, e.g. I'm pretty sure my EasyAIS has a differential NMEA input. All NMEA ver 2 devices are supposed to be differential input. I just can't understand why Garmin don't do it properly, cost implication is a few cents. Great shame, I like the plotters, I really miss my 750 compared with the Raymarine I have now due to change of boat.

If you look at any device with an NMEA input if it has 2 wires, neither of which is the DC negative wire, it should be safe to assume it's a differential input and would work with the ST60 output.
If it uses one wire plus the DC negative, like the Garmin, it is a single ended input and will not work with the ST60 output.
 
If you are using ANY of the ST 60 instruments, they will work without the Raymarine interface when linking to a device inputting/outputting 0183. I have been doing that for over ten years with no problems. However, once you move to NMEA 2000, or wish to include a Seatalk New Generation (SeaTalkng) item in your system, you will need to get an "Actisense NMEA 0183 to NMEA 2000 converter". I had to buy one of these when fitting a new autopilot last year. Raymarine DO make their own adapter but they readily admitted to me that it is inferior to the Actisense NGW-1 which is the item you need. Google it for further info.

Max.
 
Plevier said:
If you look at any device with an NMEA input if it has 2 wires, neither of which is the DC negative wire, it should be safe to assume it's a differential input and would work with the ST60 output.
If it uses one wire plus the DC negative, like the Garmin, it is a single ended input and will not work with the ST60 output.
Click to expand...

But it should. You can always connect a differential output to a single ended input. You just leave one output unconnected.

As Max K states,he's never had a problem with an ST and I can find no other info regards ST60 / Garmin incompatibility on the net.

What happens to your output that floats at 12v if you connect it to ground via a 10k resistor? I still think your ST60 is faulty so you've had to use the other output which needed the opto isolator to work. This is fine - you've got a work around which is what matters.
 
ianj99 said:
But it should. You can always connect a differential output to a single ended input. You just leave one output unconnected.

As Max K states,he's never had a problem with an ST and I can find no other info regards ST60 / Garmin incompatibility on the net.

What happens to your output that floats at 12v if you connect it to ground via a 10k resistor? I still think your ST60 is faulty so you've had to use the other output which needed the opto isolator to work. This is fine - you've got a work around which is what matters.
Click to expand...

I'm sorry to shout BUT FOR GOD'S SAKE LOOK AT THE CIRCUIT THIS IS NOT AN NMEA STANDARD DIFFERENTIAL OUTPUT!!!!!!!

Once again,
The NMEA+ output that is regulated at (approximately) 11V stays at 11V until you draw more than its current capability, 80mA I think from memory.
The NMEA- output floats for OFF (meaning of course it sits at +11V if connected to the + output with any kind of load) and goes to 0V for ON.

Thanks to Nigel, here is the output stage circuitry. Note how it is output B that switches (to DC 0V), output A is constant:


8d6075e691ecd726d293ed6f8f06d13d_zpsfa6dd9cc.jpg
 
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