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Stepper Moving Too Fast - Calculate Scale, Max Speed, Pulse Length

LIKELY STEPPER / SCALING

Summary

When a stepper axis moves too fast, stalls, or behaves strangely, the community checks are: reduce maximum speed, redo Calculate Scale, check acceleration, and make sure stepper pulse length is not longer than needed. Simon stated that step pulse only applies to stepper motors, not servos, and that for steppers 1 is fine for most, 5 for older amplifiers, and it never needs to be more. He later noted that stepper pulse length can limit top speed, and 1-2 us should be enough.

Symptoms / Questions

  • Stepper motor is moving too fast.
  • Stepper axis appears to stall, shake, or misbehave under speed.
  • Operator is told to reduce maximum speed in axis settings.
  • Operator is told to redo the calculate scale option.
  • Operator asks about Step pulse.
  • Operator is unsure whether step pulse applies to a servo such as zoom.
  • Top speed seems limited even when the requested speed is higher.

Settings Location

Task Flair location
Max speed / velocity Setups -> Axis Setup for the stepper axis
Acceleration Setups -> Axis Setup
Calculate Scale Setups -> Axis Setup -> Calculate Scale
Step pulse length Setups -> Axis Setup stepper / drive settings

Community Solutions

[LIKELY] Reduce Maximum Speed First

If the stepper is visibly too fast, reduce maximum speed / velocity in the stepper axis setup before chasing other causes.

Confidence: 0.78

[LIKELY] Redo Calculate Scale

If physical movement does not match the expected display units, redo Calculate Scale. Wrong scaling can make the axis attempt too many steps for the requested move.

Confidence: 0.76

[CONFIRMED] Step Pulse Applies To Steppers, Not Servos

Simon clarified that step pulse only applies to stepper motors, not servos such as zoom.

Confidence: 0.84

[LIKELY] Keep Step Pulse Length Short

For most stepper amplifiers, step pulse length around 1-2 us should be enough. Longer pulse lengths can limit top speed; older amplifiers may need around 5, but Simon said it never needs to be more.

Confidence: 0.80

Evidence

Timestamp User Evidence
2025-10-11 Simon Wakley Step pulse only applies to stepper motors, not servos like zoom; for steppers 1 is fine for most, 5 for older amplifiers, never more.
2025-10-21 Ivan / Stafford / Niko Stepper video discussed; answers were Too fast, reduce maximum speed, or redo Calculate Scale.
2025-10-22 Simon Wakley Stepper pulse length longer than needed can limit top speed; 1-2 us should be enough.

WhatsApp Excerpts

  • 2025-10-11 15:15 - Simon Wakley: Step pulse only applies to stepper motors not servos like the Zoom.
  • 2025-10-11 15:15 - Simon Wakley: For steppers 1 is fine for most 5 for older amplifiers never needs to be more.
  • 2025-10-21 23:22 - Stafford: Too fast....
  • 2025-10-21 23:23 - Niko: That stepper is moving too fast, try to reduce the maximum speed or redo the calculate scale option.
  • 2025-10-21 23:37 - Stafford: Reduce maximum speed in axis settings...
  • 2025-10-22 02:19 - Simon Wakley: Also make sure your stepper pulse length is not longer than it needs to be as that can limit the top speed. 1-2 us should be enough.