Understanding the CANbus

The WAM's control PC uses a Peak CAN card to communicate with each motor controller over a two-wire differential ​CAN communications bus. This is the same technology used in many cars to connect various sensors and actuators to the vehicle's central computer. As a differential signal, it is very robust to electrical noise. And its dominant/recessive bit transmission scheme coupled with its priority-based message framing structure ensures that there is no cost penalty to message collisions between two or more nodes.

For external WAM PCs:

1. Make sure that the CANbus cable is plugged into the correct port on the PC
2. Make sure that the CANbus cable is plugged into the correct port on the WAM
3. Make sure the CANbus card is properly seated in its PCI slot

CAN driver software:

1. Make sure the CAN driver is installed and loaded correctly: dmesg |grep –i pcan, cat /proc/pcan, lsmod
2. Check for IRQ conflicts

Wiring issues:

1. Check for a broken CANbus or power wire, usually in a connector or at the safety puck.
2. Check for a loose CANbus or power crimp in the connectors.
3. Make sure that the CANbus cable is properly terminated- there is a wrist or blank outer link attached.