Problem with NMEA0183

[Vipe6]

I seem to have a problem connecting some of my instruments to my autopilot. My setup is a string of ST60+ instruments (log, depth, wind and graphic) and a BCALMXP autopilot. This autopilot only accepts NMEA0183 but that shouldn't be a problem as the graphic display from Raymarine has an NMEA talker. Yet, the autopilot doens't seem to 'hear' the info. When I connect the NMEA wires to my mulitmeter though (setting the meter to diode testing with sound) I get a short burst every two seconds suggesting that it is sending data. I have already switched the wires but no effect. I also have a multiplexer and when I connect the ST60+ to the input, there's no signal coming out suggesting that there maybe something wrong with the signal. The whole set is connected to a Raymarine RC435i plotter and this interfacing seems to work fine because I can get SOG and true wind etc on my instruments (RC435i is connected to the others with the NMEA connections). I'm at a los and starting to think that I'm overlooking something. Anyone have any suggestions as to what I'm doing wrong?

[CarinaPDX]

It is common for MFDs to have a menu to select the "sentences" to output over 0183, so first check which sentences are being output. Also check which sentences are understood by your AP, and that the one (or more) output by the MFD is/are recognized by the AP.

Greg

[CarinaPDX]

I just checked the manuals. The output sentences of the RC435i will satisfy the GPS input needs of the autopilot, so that should work with a direct NMEA 0183 connection - but check that the AP is set to 4800 baud (the standard for basic NMEA 0183). The ST60+ Wind instrument outputs in SeaTalk and needs the multiplexer to translate to NMEA 0183 sentence MWV, and again at 4800 baud. Thus for the whole system to work the RC435i should be connected to an NMEA input to the mux, and the ST60+ Wind connected to an input with SeaTalk translation, and the output to the AP - with all speeds set to 4800 baud.

Greg

[smac999]

if your plotter can output nmea 183 I have no idea why you'd be trying to take it from the st60's as then you'll also have gps and navigation data (steer to waypoint) the plotter is also likly already connected to the ST60's via seatalk? so you'll also get wind data from the plotter nmea183 if that is what you are looking for.

I have never tried to output nmea 183 from a st60 so I can't tell you why it's not working.

the proper way to diagnose nmea 183 is with a laptop, serial port, and a terminal program.

[donradcliffe]

Yep, I spent this afternoon troubleshooting NMEA output of a garmin MFD. I breadboarded the output of the Garmin--NMEA+ out to pin 2 of a 9 pin serial port, and NMEA- out to pin 5. Used a serial to USB converter and hyperterminal on windows XP (built in to XP, but missing from W7, 8 and 10) and got all the detailed NMEA sentences the MFD was puttuing out.

[smac999]

you can copy the hyperterminal exe file from windows XP into win 7 and it'll work. it's only one file. I haven't tried newer windows

[CarinaPDX]

Originally Posted by smac999

if your plotter can output nmea 183 I have no idea why you'd be trying to take it from the st60's as then you'll also have gps and navigation data (steer to waypoint) the plotter is also likly already connected to the ST60's via seatalk? so you'll also get wind data from the plotter nmea183 if that is what you are looking for.

The RC435i is about 15 years old: it is a GPS and plotter only. It is capable of putting its own data out onto SeaTalk, not reading the data from other SeaTalk instruments. It also has no facility for displaying such data or converting to NMEA 0183.

I have never tried to output nmea 183 from a st60 so I can't tell you why it's not working.

Probably because it does not have NMEA 0183 output, only SeaTalk.

the proper way to diagnose nmea 183 is with a laptop, serial port, and a terminal program.

It is not clear to me that such heroic efforts are required (yet). And in the event beyond the skill level of most cruisers.

Greg

[smac999]

Originally Posted by CarinaPDX

Probably because it does not have NMEA 0183 output, only SeaTalk.

It is not clear to me that such heroic efforts are required (yet). And in the event beyond the skill level of most cruisers.

Greg

His first post says it does.

If it is not working the laptop check is next step.

[Vipe6]

The wind instrument on itself doesn't have nmea output but it's attached (via seatalk) to a Graphic instrument which does have an nmea in and output. I'm assuming it's nmea0183. I will try connecting the seatalk from these instruments to my mux and see if that works. Means removing the hatch garage though which is quite a lot of work. I just want to connect the wind instrument, not the RC435i because my autopilot gets GPS-data from my smartphone which is also the remote control and MOB alarm for the autopilot. I do know that the RC435i does not put out any wind data although it's connected to the nmea out of the ST60+ graphic. Tried an nmea terminal on windows too, couldn't see any data passing. That's why I was wondering if there was something I might have overlooked.

[Beausoleil]

Originally Posted by Vipe6

The wind instrument on itself doesn't have nmea output but it's attached (via seatalk) to a Graphic instrument which does have an nmea in and output. I'm assuming it's nmea0183. I will try connecting the seatalk from these instruments to my mux and see if that works. Means removing the hatch garage though which is quite a lot of work. I just want to connect the wind instrument, not the RC435i because my autopilot gets GPS-data from my smartphone which is also the remote control and MOB alarm for the autopilot. I do know that the RC435i does not put out any wind data although it's connected to the nmea out of the ST60+ graphic. Tried an nmea terminal on windows too, couldn't see any data passing. That's why I was wondering if there was something I might have overlooked.

The NMEA0183 output of the ST60+ Graphic repeater only supports a subset of older NMEA sentences. If you're looking for wind info for your AP to sail to a constant wind angle, that should work. However, how many NMEA ports does your AP have? You'd need at least two - one for the GPS data from the RC435i, and one for wind from the ST60+ NMEA out. Otherwise, feed the NMEA data from both into your NMEA multiplexer (you indicated it supports Seatalkv1? - try that instead).