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CAN bus

The control board has a CAN bus for the electric grippers, wired to the M8 connector at the forearm. The board is the master: it sends the gripper the command from the PC's packet every cycle (a move, a calibrate, a clear error, or an empty status poll when nothing changed) and relays the gripper's answer back to the PC.

  • Bit rate: 1 Mbit/s, the grippers' rate.
  • Node ID: the gripper's CAN ID, 0 as shipped; the PC packet carries the ID the board addresses, so a gripper with another ID works if the software is told.
  • Termination: 120 Ω at each end of the bus. At the board end, the CAN1 JUMPER connects the board's 120 Ω resistor when it is on; at the other end, the gripper has its own termination switch, on as shipped (CAN bus).

A second CAN controller is on the board, but its transceiver is not populated: CAN 2 is for your own experiments. More axes on the bus, a seventh axis or a second gripper, are not supported by the firmware or the software yet; the protocol the grippers speak is documented in the STEPFOC and Spectral Micro references for anyone who wants to extend it.

The electrical side is in CAN bus of the Control Board Manual.

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