Hi there freaks - I want to run a single cable with as few conductors as possible that carries CAN and power that will be subjected to all sorts of tortures. It needs to carry CAN signals at 1Mbps, ground, and +12V I want it to be able to handle and detect both shorting of any wire to any other wire and opening (breaking) of any wire
This seems... tricky. My first idea was to run 8 wires: two sets of CAN lines, and two sets of both ground and +12V. If the first CAN bus went down the system would just have to switch over to the second bus. This would require two CAN controllers, at least with the way I was thinking about implementing it. Not great, but not terrible. But then I realized that if one CAN line from one bus got shorted to a CAN line from the other bus, it could take down both CAN lines unless the system was smart enough to disable all the CAN transceivers on one bus (it'd be pretty tricky to get that right... but possible). There'd be current sensing on each power line (so 4 current sensors/node) and if current became drastically unbalanced it'd show that there was a wiring fault. Dealing with a short from ground to +12V would be tricky though - would require having switches on the bus to "shut down" a wire.
Is this something any of you has dealt with before? I figure it's best not to reinvent the wheel...