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Acceleration and Velocity Limits in EtherCat Position Mode

When using the AKD with EtherCAT in Position mode, are the AKD's Acceleration, Deceleration, and Velocity limits active?

No they are not.  The accel, decel, and velocity needs to be managed by the trajectory generator in the EtherCAT master.  This is because there is no mechanism in EtherCAT to handle an axis that hits a limit programmed in the drive.  The AKD cannot tell it's EtherCAT master "I cannot follow your trajectory because I have an acceleration limit."  Instead, the AKD's programmed accel limit would create a position error, and the EtherCAT master would respond by altering the position command, creating more position error.  This cycle would create an oscillating load.  For this reason, the AKD's accel, decel, and velocity limits are not active when the AKD is being controlled in EtherCAT Position mode.



Frevel's picture

i am using the AKD Servo Drive with the AKM12E and LabView.
The velocity and torque mode are working fine, but when i use the position mode i get the message that the
velocity threshold is exeeded (and the engine stops). If the Problem lies at the EtherCat Master, how can i set the limits on it?

kind regards