[wireties]

Originally Posted by ratdude747

QFT. Any time termination matters (such as CAN), you've entered the wonderful world of RF where reflections and the like are real. In RF you get to throw away everything you know about electricity and circuits, aside from Kirchoff's laws. Ohm's law? Kiss it goodbye, it doesn't apply any more. Wire spacing and twist rate do matter a ton.

All the normal rules still apply but there are additional rules (terms in the equations). You are looking at the complex impedance of the load (which did not factor in at low frequencies) rather than simple resistance. The size and shape of the wire and connector pins all matter because they help determine the reactance portion of the impedance (resistance plus reactance). Balancing the impedance of the source and the load become important to reduce mismatches that can cause ringing (reflected waves bouncing around willy-nilly).

So for CANbus the sources have a particular output impedance that performs best when the load has a matching impedance (same resistance and opposite reactance). To keep things simple use wire much like the green/yellow that comes with the Talons. Use connectors with cross sections close to the cross section of the wire. Wire things in series from source to load (like CTE recommends and the CANbus standards dictate). Use a 100-ish ohm resistor for the load (termination). To do otherwise is to ask for troubles that are very difficult to diagnose.