Here is my current situation (Not resolved)

I have the following equipment which may be relevant. Raymarine S2G course computer controlled by a ST6001, ST60 Tridata, ST60 Wind and ST60 Multi.

I want to get NMEA data (Wind & Depth) into the 9 pin serial port on my laptop. For investigative purposes I am using Windows XP home edition and HyperTerminal to look at what is coming in, although I use Chartwork's Winchart NautiQ for navigation.



If the laptop is not connected to anything at all (including power supplies) I get valid NMEA messages from the NMEA Out from the Multi. If I connect the laptop to the boats 12v supply via a cigarette type laptop power supply, or an inverter using the normal laptop power lead I get nothing.


Equally if I connect the USB port via a Serial to USB lead to the GPS and AIS input I immediately loose the NMEA input.


If, with the computer isolated and the NEMA going in correctly via the serial port I connect the optocoupler input across the NEMA out terminals I again loose the signal. It is as if there isn't enough power in the NEMA signal to power anything.

I have replicated everything on my son's laptop, a totally different make so I think we can eliminate the computers. I can connect the laptop through a cigarette type laptop power supply to an external car battery and again no problem.

If I connect the negative of this spare battery to the negative of the ship's battery I immediately loose the signal.


2 other things. If I put a GPS signal into the serial port there are no problems even when the laptop is connected to the ship's power supply again confirming that the laptops seem OK and that HyperTerminal is configured correctly.



Here are various voltages that may give you some clues. Obviously measures with an electronic multi meter as I do not have a 'scope. Negative of meter connected to Negative of boat

NMEA output from Multi with nothing connected to it.

NMEA Out Negative to Ships Negative Fluctuating between -0.3 & 0.0v

NMEA Out Positive to Ships Negative 11.7v

NMEA Out Positive to NMEA Out Negative Fluctuating between 5.5 & 0v (Normal NMEA output)



Laptop connected to ships 12v supply though car type power supply. Nothing else connected.

Voltages on RS232 9 pin plug

Pin 5 to Ships Negative 0.18v

Pin 2 to Ships Negative 0.24v

Pin 2 to Pin 5 .05v



NMEA Out plugged into Laptop Serial Port, laptop on internal batteries. No other connections to laptop

NMEA Out Negative to Ships Negative Fluctuating between 8.8 & 4.7

NMEA Out Positive to Ships Negative 11.9v

NMEA Out Positive to NMEA Out Negative Fluctuating between 3.3 & 0v (NMEA received correctly)



NMEA Out plugged into Laptop Serial Port. Laptop connected to ships 12v supply though car type power supply

NMEA Out Negative to Ships Negative 0.2v

NMEA Out Positive to Ships Negative 11.6v

NMEA Out Positive to NMEA Out Negative 11.4v (No NMEA input detected)





NMEA From GPS plugged into Laptop Serial Port, laptop connected to ships 12v supply though car type power supply

NMEA Out Negative to Ships Negative 0.2v

NMEA Out Positive to Ships Negative Fluctuating between -3.0 & +0.2

NMEA Out Positive to NMEA Out Negative Fluctuating between -3.3 & +0.8 (GPS messages received correctly)



So there we are, getting NMEA out, but not in



Phil





"Arnold" wrote in message ups.com...
hey people,

a milestone for me, and possible, others:
raytheon answerd my mail, and said that an other instrument with native
NMEA support does recognise the sentences/data properly and that I
should try to connect the PC through that device. so the solution would
be, link a NMEA repeater to the NMEA OUT port and link the PC to that
thing.

as I just figured out, my Navtex receiver (furuno Nx-300) will, most
likely, do just that, with a semi-official rs-232 connection to it.
(semi, couse you have to put your own rs-232 plug on to the correct
wires).
I'm gonna keep you guys informed on later developments.

greetings,
Arnold