Cyclic modes

In cyclic synchronous modes reference values are sent and updated with each EtherCAT communication frame, so a reference signal has to be sent with up to 4 kHz. As an example, to rotate the motor shaft from position A to position B in cyclic synchronous torque mode within one second, the following information has to be sent to the drive:

  • position A in the beginning
  • 3998 intermediate positions (at 4 kHz)
  • position B in the end

OBLAC Drives uses the cyclic synchronous position, velocity and torque mode to control the drive. Even though the application accepts inputs like velocity and acceleration, this just means that this information is used within the application to compute a reference trajectory. This trajectory is then sent to the drive in the form of individual setpoint values.

However, for some robotic applications it can be helpful to generate such trajectories directly on the drive which means that the high-level robot control will not have to deal with this task. You can do so using EtherCAT communication and the following objects:

Object Meaning Unit
0x607A Target position inc
0x60FF Target velocity inc/s
0x6071 Target torque Per thousands of rated Torque

Use this object to directly select a Target position

Use this object to directly select a Target velocity

Use this object to directly select a Target torque