Catch Up Motion

When two-dimensional pitch error compensation is enabled, the initial offset is often not 0. If the initial offset is immediately applied, the command position that is sent to the servo will suddenly change, potentially causing the compensation axis to move or an alarm to be generated. To prevent this, the Catch Up Velocity and Catch Up Acceleration parameters can be specified to gradually apply the initial offset.

When two-dimensional pitch error compensation is enabled, the initial offset is calculated, and then gradually applied using a Trapezoidal Profile with the specified catch up velocity and catch up acceleration. This motion to apply the initial offset is called catch up motion.

The compensation axis and the two reference axes can be freely moved by motion commands while executing the catch up motion. Any changes to the offset resulting from the motion are applied immediately, and will not affect the time that the catch up motion takes to complete.

These parameters have no effect beyond applying the initial offset. If two-dimensional pitch error compensation is disabled, and then enabled again, the initial offset is again applied gradually using these parameters.

If either of these parameters is set to 0, the initial offset is applied instantly.