NMEA 2000, the power story

Hey, I actually can build something more substantial than sentences! Below is a plywood creation (bigger here) that will let me test the borrowed Maretron products (everything shown) and other NMEA 2000 gear either in my shop or clamped to my test boat, Gizmo. Note that all six devices shown not only share data through the rugged “Micro” size 2000 cable, but get power from it. That yellow wire is the 12v tap, supplying up to 4 amps to each side of the trunk line, which in this case is very short. Compass, 2000–PC USB gateway, GPS, and display are all on the upper or left side of the trunk. Depth/speed/water temp transducer, network test meter, and tees for the two plotters (separately powered) are on the other side. If I’d used heavier “Mini” size cable, there could be 8 amps available on either side of the tap. Putting together this little network was way easier than chopping up the plywood but there are details, like the Terminating Resisters at the trunk ends, you have to know about. Maretron has put together a useful “NMEA 2000 network designer’s guide” (and cable catalog) which is in PDF form here (if you just view individual pages, the guide portion starts on 17).