Chapter · CAN bus
The rail
The two ends, how far and how fast, which ground, and what to check when nothing arrives.
- 10The two ends4 minA 120 ohm block at each end of the rail stops edges bouncing back. Powered off, the rail then measures about 60 ohm, and a third block or a long branch is a mistake.
- 11How far, how fast, which ground5 minA signal must go to the far device and back inside one bit, so a faster rate means a shorter rail. The receivers also need the grounds close enough to keep both wires in their window.
- 12When nothing arrives5 minFour symptoms cover most first failures on a CAN rail. Each has several possible causes, so a symptom is a clue and the way through is to change one thing at a time.
Start at 10 and read down — the order is the order things get easier in. Or take the one with your part in it; every article stands on its own, and links back to whatever it needs.