NMEA compass to Raymarine SL72 radar

[SteveB_Sigma33]

I have put a NASA NMEA compass on board my boat but can't seem to make it talk to my radar or my Furuno GPS.

It has a red and blach for power and a blue as the NMEA output, however when I connect the blue to any of the NMEA channels of either device I get no apparent response from either device.

I was expecting COG to reflect the course from the compass!

I do get a voltage out of the blue cable so I'm taking it the compass is working fine.

Both devices are configured for NMEA in/out

Am I being a complete dollard!!!!

 

[ShipsWoofy]

You need to ground the signal.

blue should go to nmea in on SL72 (+nmea orange)
black (-12v on compass) should go to -nmea (yellow)

hope this helps, it is always difficult being remote from the set up, but from what I can glean from manuals I have the colour codes correct, if not adjust accordingly.

I will be interested to know how the nasa performs with the SL72, would you mind reporting back when you find out.

 

[Danny]

[ QUOTE ]

I was expecting COG to reflect the course from the compass!

[/ QUOTE ]Do you mean COG on the GPS receiver? This won't change. It's calculated solely from the satellite data and reflects the actual movement of the boat with respect to the planet and has no direct relationship to the boat's heading.

I can't think of any information that the compass and the GPS receiver would need to share. The input to the GPS is normally used for receiving corrections from an external DGPS beacon receiver or for loading waypoints into the GPS from another device.

 

[TonyS]

I have the RM SL72CRC combined plotter and radar. In setup you can press and hold down enter for more than 5 secs and it then gives a new set of soft menues one of which is nmea. If you press that it shows what is being received on the left and sent on the right. If it not the same on yours I suggest you give RM a call and ask how to do it.

 

[crossbones]

The nasa compass gives out nmea message HDG. The signal is referenced to the supply negative so, as Dogwatch said, you need to connect the -nmea on the receiving end to supply negative. The output is only 5volt peak to peak which for some equipment is too low. A 2k2 resistor between the output (blue wire ) and 12volt supply will increase the output level.