Glossary · Motion control and drives
Step loss
Also known as: Lost steps, Loss of steps
German: Schrittverlust
In stepper motor control, step loss is the condition in which the rotor fails to follow the steps commanded by the driver, for example due to overload, excessive acceleration or resonance, so that the actual position deviates from the position counted by the controller.
- Motion control
In one sentence
Step loss means the stepper rotor did not follow commanded steps, so the real position no longer matches the counted position.
Example
After a jam in the infeed, the stepper-driven format guide lost steps, and parts were misaligned until the axis was homed again.
How it applies
- Engineering: Step loss is prevented by torque reserve, suitable ramps and resonance damping. It can be detected with an encoder or with sensorless Stall detection.
- Commissioning: Test the ramps with the real load and at the worst-case supply voltage; step loss often appears only at certain speeds.
- Operation: Without feedback the controller does not notice lost steps. The position error adds up with every event until the axis is homed again.
- Documentation: In troubleshooting, describe the symptoms (offset positions, loud rattling, motor stops while pulses continue), the causes and the remedy, including Homing after the cause is removed. Don't call a lost step a motor defect when the cause is overload.