Requested set velocity is not allowed

What does 4221 mean?

The velocity value requested for a positioning task is invalid, either being zero or negative, exceeding the axis's 'maximum velocity', or, for servo drives, exceeding the axis's 'reference velocity'. An unacceptable velocity can lead to an axis not moving, overspeed conditions, or triggering other safety limits.

• Commanded velocity (e.g., F-word in G-code, target velocity parameter) is set to 0 or a negative value.
• Requested velocity exceeds the axis's configured maximum velocity parameter (e.g., P6-05 'MaxVelocity').
• For servo drives, the requested velocity exceeds the drive's configured reference velocity (e.g., P7-03 'ReferenceSpeed').
• Scaling error in the NC program or HMI causing an erroneously high velocity command due to unit mismatch.
• Units mismatch between the NC program and the axis configuration (e.g., mm/s vs. inches/min).

Click steps to track your progress.

1. 1

   1. Examine the NC program or PLC command for the specified velocity value and correct it to a positive, non-zero value.

2. 2

   2. Adjust the axis's maximum velocity parameter P6-05 ('MaxVelocity') to be equal to or greater than the commanded velocity.

3. 3

   3. For servo drives, verify the drive's reference velocity parameter P7-03 ('ReferenceSpeed') is correctly configured for the motor.

4. 4

   4. Check for unit consistency (e.g., G20/G21 for inches/mm) in the NC program and the axis configuration (e.g., P4-10 'ScaleFactor').

5. 5

   5. Run a simple jog command at a low velocity to confirm basic velocity control functionality of the axis.