Measure twice. Slice once.

Motion reference

Stepper Motion, Steps per mm and Rotation Distance Reference

Keep motor resolution, drive travel, firmware units, and measured correction in the right order.

Motor and driver terms

Full steps per revolution = 360 ÷ motor step angle. A 1.8° motor has 200 full steps; a 0.9° motor has 400. Microsteps are the subdivisions configured in the stepper driver and firmware. Higher microstepping can smooth motion, but theoretical subdivision is not the same as guaranteed positioning accuracy.

Belt and screw travel

For a synchronous belt axis, travel per pulley revolution = belt pitch × pulley teeth. For a lead screw, lead = pitch × thread starts. A reduction ratio multiplies the motor steps required for one output revolution.

Firmware relationships

Steps/mm = full steps/rev × microsteps × ratio ÷ travel per output revolution. Klipper rotation_distance is the travel per full motor revolution, or full steps/rev × microsteps ÷ steps/mm for a direct axis.

Measured correction

Corrected steps/mm = current steps/mm × commanded distance ÷ measured distance. Corrected rotation_distance uses the inverse ratio. Apply this only to repeatable direct-travel error after checking mechanics.

Pulse rate

Pulse rate in steps/s = steps/mm × mm/s. Motor RPM then follows from pulse rate and configured microsteps. Controller headroom and motor torque are separate constraints.

Engineering cautions

Backlash, compliance, belt tension, pulley eccentricity, screw error, resonance, driver current, and frame alignment are not corrected by theoretical resolution. Verify machine changes at low speed before restoring normal acceleration and travel limits.

Primary documentation

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