Requested traverse distance is not allowed
Beckhoff · TwinCAT 2 NC
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The commanded traverse distance or looping distance for a two-speed axis is smaller than its configured braking distance. This means the axis cannot achieve the commanded move reliably, as it would require stopping instantaneously or reversing before completing the minimum necessary travel. Attempting this move can lead to inaccurate positioning or overshooting.
Vanlige årsaker
- Parameter P-AXIS-00008 (Braking Distance) configured significantly higher than the actual available physical traverse distance.
- The commanded traverse distance from the motion program (e.g., MC_MoveAbsolute) is mathematically less than the calculated braking distance at current deceleration.
- Axis deceleration parameter (e.g., P-AXIS-00007 or drive-specific deceleration) is set too low, resulting in an extended braking distance.
- Unexpected increase in mechanical load or friction on the axis, causing the actual braking distance to exceed the configured value.
- Kinematic limitations of the mechanical system not correctly reflected in the axis motion parameters for two-speed operation.
Reparasjonssteg & Sjekkliste
Klikk på steg for å spore fremgangen.
- 1
1. Measure the actual physical minimum traverse distance of the axis using a calibrated measuring device (e.g., ruler, laser sensor).
- 2
2. Review and adjust parameter P-AXIS-00008 (Braking Distance) in the NC configuration to a value below the physically shortest commanded travel.
- 3
3. Check the axis deceleration parameter (e.g., P-AXIS-00007) and increase it if permissible by the mechanical system and drive capabilities.
- 4
4. Modify the motion program (e.g., PLC logic or NC code) to ensure all commanded traverse distances are greater than the calculated braking distance.
- 5
5. Execute a test move with reduced velocity and acceleration/deceleration, monitoring the actual stopping distance with a position feedback sensor.