Checking NMAE feed

[Vara]

Playing with an old plotter, does not seem to be transmitting NMAE data.

Is there any way of detecting signal using a multimeter or similar?

 

[david_bagshaw]

aparently nema data can be detected with a led between the signal and ground wires, (obviously the nema out pair), seen as flashing.

 

[prv]

NMEA

The ideal would be an oscilloscope, failing that I would try connecting to a PC serial port. Some other NMEA kit (eg my CP180i plotter) has a diagnostic mode in which it displays everything it reads on the input.

Pete

 

[elton]

aparently nema data can be detected with a led between the signal and ground wires, (obviously the nema out pair), seen as flashing.

What value resistor did you put in series with the LED?

 

[Vara]

NMEA

The ideal would be an oscilloscope, failing that I would try connecting to a PC serial port. Some other NMEA kit (eg my CP180i plotter) has a diagnostic mode in which it displays everything it reads on the input.

Pete

Had a quick look in the shed no oscilloscope, bit short of serial ports on the Ipad, cant see a diagnostic mode.

I'll just put it on ebay as a spares job as everything else seems to work OK, I don't really need 3 plotters.

Thanks all.

 

[nigelmercier]

What value resistor did you put in series with the LED?

I was going to mention that, about 1kΩ would be best, but it's not the ideal way.

I can recommend a very handy tool for troubleshooting NMEA or SeaTalk data, a Logic Probe.