2.1 KiB
2.1 KiB
+++ title = "CiA402" author = ["Dehaeze Thomas"] draft = false category = "Electronics" +++
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CiA 402 (IEC 61800-7-201) is the CAN in Automation standard drive profile for servo drives, stepper drives and frequency inverters. It defines a common object dictionary and state machine, so that drives from different vendors behave the same way. It was defined for CANopen and is also used over EtherCAT (CoE, CANopen over EtherCAT).
Main elements
- Control word (0x6040) and status word (0x6041): commands sent to the drive (enable, fault reset, ...) and its feedback.
- State machine: the drive has to be walked through fixed states before it moves: Switch on disabled, Ready to switch on, Switched on, Operation enabled, Fault.
- Modes of operation (0x6060 requested, 0x6061 actual):
- Cyclic Synchronous Position (CSP): a target position is sent every cycle (e.g. 1 ms). Used for real-time control from a master.
- Cyclic Synchronous Velocity (CSV) and Torque (CST): same with velocity or torque setpoints.
- Profile Position (PP) and Profile Velocity (PV): the drive generates its own trajectory to a target.
- Homing: the drive runs its own homing procedure.
- Standard objects: target position (0x607A), actual position (0x6064), velocity and acceleration limits, position factor / scaling.
Use with a real-time target (e.g. Speedgoat)
- The master needs the ESI file and a PDO mapping with at least control word, target position, status word and actual position.
- A small state machine (e.g. Stateflow) brings the drive to Operation enabled before setpoints are sent.
- In CSP, the drive internal loop still does the actual control, the master only provides setpoints.
- A generic CiA 402 block can be reused across compatible drives. The ESI file, PDO mapping, units, optional objects and vendor quirks are still drive specific.