By Dovydas Kersys · Chapter 24 of 58 in Machine Commissioning.
Before you begin: Follow the machine documentation, risk assessment, site procedures and lockout/tagout requirements. Commissioning can expose personnel to electrical energy, stored pressure and unexpected motion. Never defeat a safety function merely to make a test easier. Examples and diagrams are generic and must be checked against the actual machine.
Servo systems require correct motor/drive pairing, encoder feedback, safety signals, motion commands and mechanical load data. Commissioning should begin with low energy and conservative motion limits.
Servo commissioning closes a feedback loop; direction and feedback must agree before performance tuning.
Why this matters during commissioning
Servo axes can produce high torque instantly. Incorrect feedback polarity, scaling or tuning can cause violent oscillation.
Commissioning procedure
- Verify motor, encoder and drive model compatibility.
- Confirm power, brake, STO and feedback wiring.
- Load correct motor data and encoder type.
- Establish low speed/acceleration limits for first motion.
- Jog in both directions while watching feedback position and following error.
- Perform approved tuning only after mechanics and feedback are proven.
- Record final tuning/limit parameters.
Common failure patterns
- Encoder polarity creates positive feedback instead of negative feedback.
- Motor brake released too late or too early.
- Travel limit not configured before first move.
- Auto-tune performed with loose coupling or abnormal load.
Evidence to record
- Drive/motor identifiers
- Feedback type
- Travel limits
- Direction result
- Tuning values
- Following error / current observations
FIELD RULE: If an axis oscillates, stop and verify feedback direction and mechanics before increasing gains.
Continue the series
- Previous chapter: Motor Direction and Phase Rotation: Commissioning Guide
- Next chapter: Encoder and Feedback Verification: Commissioning Guide
- Browse all Machine Commissioning chapters
Adapted from Machine Commissioning for Maintenance and Automation Technicians, by Dovydas Kersys. © 2026 Dovydas Kersys. Featured cover image is an AI-generated editorial illustration.