Seatalk - NMEA

[skvis]

The case is:

Bought the Raymarine NMEA/Seatalk interface, for the purpose of getting NMEA OUT to my laptop. The interface i sending all sorts of NMEA-sentences (eg. wind, depth, temperature, speed), but no GPS-sentences.

I have an ST60 network, with a tridata instrument, wind instrument, multi instrument, and a ST 5000+ instrument. All conected to each other with seatalk. In addition I have a Raymarine 435 plotter, which is wired with the NMEA protocol directly to the NMEA IN at the autopilot instrument. GPS-information from the plotter is available at my multi-instrument (via seatalk?).

The NMEA interface is wired via seatalk to the autopilot instrument.

Then, as I said: My PCs plottersoftware is reading all sorts of NMEA sentences, but no GPS information.

Anyone who will suggest an solution?

 

[Fr J Hackett]

Is your GPS a Raymarine and if so is it connected to give NMEA output the 125 can be configured for either Seatalk or NEMA. If it is configured for NEMA output then there will be no GPS sentences on the Seatalk bus.

 

[rrees]

you mention that the 125 can have nmea or seatalk
When i stripped the cables back I noticed that it has there wiring for both
are they both live

 

[PembrokeshirePromise]

As Pete says - with your setup it sounds possible (likely even if you have a DSC radio ?) that the GPS might be configured / wired for NMEA so the output could be fed to both your plotter and your radio.

With your new setup - you should be able to change this to seatalk - and the split your new NMEA out between you DSC and laptop

Speculating a bit - but it could be ...

 

[nigelhudson]

The ST60 multi-instrument has NMEA input and output - we have ours connected to the output of our Lowrance plotter and we get a full range of GPS data displayed on it. However we haven't tried connecting the multi NMEA output to another device yet to see whether we get the full range of data - you might try that output rather than the interface box.

 

[exfinnsailor]

Raymarine Technical are very good .. Had a chat on more than one occasion .. Does your Plotter Re-Transmit the Sentence it receives from the GPS Receiver .. May be cheaper just to add a USB GPS Receiver to the laptop .. You then have two systems just in case one fails ..

 

[jfkal]

The box adds a prefix to the NMEA sentence and not all PC programs can cope with that.

 

[Gypsy]

I have the Raymarine ST-NMEA unit and a Raystar 112 external GPS (6yrs old) which outputs SeaTalk. The converter properly outputs NMEA GPS info (RMS, GLL, GGA, GLL) as well as the same on the RS232 o/p. So it definitely should work if the data is on the ST bus.

How does the Multi Instrument get its data? Is there an NMEA connection? Since the 435 only outputs NMEA you are relying on the 5000 to convert the NMEA to ST. Have you tried connecting the ST-NMEA box to the ST output of the Multi?

The Multi is obviously getting GPS data from somewhere, my bet it is from NMEA. I checked the manual of the Multi, it will send out ST versions of RMC, RMB and GLL on its ST connector. So the solution would seem to be to simply take the ST for the converter from the Multi instead of the 5000.

Alternatively, if you only want to "listen" to the NMEA GPS data, wire the PC in parallel with the 435 NMEA output, you can usually drive 3 listeners from one talker.

 

[Piddy]

Hi

If the Autopilot is steering to a GPS waypoint or seeing the positional data it suggests the problem is the recognition of the NMEA data by the laptop program.
Try using hyperterminal to see the raw data coming in rather than the nav program.

Cheers

 

[captainslarty]

Hi,
try setting the charting software to RMC
what is the charting software ??.. have you a method of listing the incoming data as in maxsea ?..

Also, you could try hyperterminal in windose set to 4800 none 8 1 and look at the data. Usually its just a matter of your pc software expecting, say, gll, but getting rmc.. there is normally a selection menu for this.

 

[jfkal]

Agree. Setting to RMC could work.

 

[jfkal]

You may want to test to connect the GPS/ Plotter to the NMEA IN of the converter box. That gives you GPS on Seatalk for the pilot but avoids problems which you may have picked up along the way NMEA-PILOT-SEATALK-CONVERTER-PC. Seems odd to me anyway since my ST5000 does NOT repeat the GPS data to the SEATALK Bus but keeps it to itself. Further: Is your converter the type with the LED's inside? If not you have an older version which still may have one or the other bug /forums/images/graemlins/frown.gif(

 

[saltwater_gypsy]

I just took the yellow Seatalk wire to a NASA clipper unit and got perfect GPS data.

 

[Marsupial]

From what you say the 435 is listening to NMEA from the autohelm. Why not interupt that feed and take it to your laptop? no need for a seatalk nmea interface, but I suspect the 435 is seatalk, seatalk can take priority if both formats are present in raymarine gear - look in the manual for the course computer it explains this complicated situation quite badly.

I assume you can see nav info on the ST5000+ instrument cog, sog, position etc, if that is the case then the same info will be converted by the interface in an order of priority mentioned in the blurb to nmea which your laptop could read.

If the sentences are scrambled on the laptop it could be the baud rate that is the problem the laptop end must be set the same as the sending end. Look at ports in system hardware setup - suck it and see - try all the speeds untill it works!

good luck - publish your findings

 

[Oldhand]

List of sentences form the manual below indicates the GPS sentences can't be in the Seatalk data stream, so the answer that you plotter may be set to NMEA out and not Seatalk out sounds logical.

3.1 NMEA Output
Provided you have the appropriate SeaTalk instrumentation, the
data listed below is transmitted in NMEA 0183 format for use with
non-SeaTalk equipment.
Note: NMEA is also output in response to NMEA input.
Data Transmitted NMEA Header
Apparent Wind Angle MWV, VWR
Apparent Wind Speed MWV, VWR
Bearing to Waypoint BWC, APB
Course Over Ground (M) VTG
Cross Track Error APB, XTE
Date ZDA
Depth DBT
Distance (Log) VLW
Distance (Trip) VLW
GPS Fix/No Fix GGA, GLL
GPS HDOP GSA, GGA
GPS PDOP GSA
Data NMEA Header
GPS Satellite Azimuth GSV
GPS Satellite Elevation GSV
GPS Satellite PR Number GSV
GPS Satellite SNR GSV
GPS Differential Station ID GGA
GPS Differential AGE GGA
GPS Number of Satellites GGA

 

[Gypsy]

Hello my salty namesake.....maybe I missed something but if you are referring to plugging the Yellow SeaTalk data into a Nasa Clipper GPS repeater then I think you have a converter hidden behind the scenes. The Clipper manual says it only reads NMEA (and v2.0 preferred). ST and NMEA are dramatically different signals both electrically and in the data construct so unless the reading device is manufactured for ST and has internal conversion I suspect you are putting an NMEA signal into the NASA, not ST. Please correct me if I am wrong. I know a bit about both ST and NMEA but have only the NASA manual to guide me.