4220

Group not ready / group not ready for new task

Beckhoff · TwinCAT 2 NC

What does 4220 mean?

The NC group received a new motion task while it was still actively processing a previous task. This request is rejected to prevent interruption of the existing task and maintain motion integrity. Attempting to force a new task can lead to unpredictable motion, collisions, or data inconsistencies.

Additional Steps

Steps 1–2 are listed in Priority Fix.

  1. 3

    Utilize command buffering mechanisms if sequential tasks are required, ensuring proper synchronization.

  2. 4

    Check group status flags (e.g., 'Busy', 'Active') before sending new instructions.

Source: Beckhoff TwinCAT 2 NC
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