Step-by-Step Diagnosis:

1. Check Command Source – Ensure the controller (e.g., PLC) is actually sending pulses (indicator light flashing).
2. Verify Wiring – Confirm power, control, and encoder cables are connected correctly and free from damage.
3. Check Brake – For brake-equipped models, ensure the brake coil is energized and released.
4. Control Mode – Make sure the driver is in position control mode, not torque or speed mode.
5. Pulse Type Match – Confirm pulse type (pulse + direction, or A/B quadrature) matches driver settings.

Possible Causes:

1. Power Cable Issue

• Cause: Loose phase connection (U, V, W) causing abnormal current.
• Solution: Retighten all motor power connections.

2. System Oscillation

• Cause: Excessive velocity loop gain, leading to vibration even at standstill.
• Solution: Lower gain or re-run auto-tuning.

3. Mechanical Locking

• Cause: Damaged bearings or foreign objects jamming the shaft.

• Solution: Power off and rotate the shaft by hand. If resistance is high, inspect and repair the motor.

Causes & Fixes:

• Electromagnetic Interference

• Check if power and encoder cable shielding is grounded properly.
• Avoid routing encoder cables alongside high-voltage inverter lines.

• Parameter Settings

• Reduce position loop gain if set too high.
• Increase “in-position tolerance” so the motor doesn’t endlessly micro-adjust.

• Mechanical Issues

• Inspect couplings, alignment, and load balance.

• Load Inertia Torque: $T=J\times \alpha$ (J = inertia, α = angular acceleration).
• Friction Torque: To overcome mechanical resistance.
• Gravity Torque: For vertical axes (Z-axis).
• External Forces: Such as cutting force.
• Rule of Thumb: Add 20–30% safety margin after calculations.

• Definition: Ratio of load inertia to motor rotor inertia.
• Importance: If the ratio >10:1, response becomes sluggish, overshoot and vibration occur.
• Ideal Ratio: ≤5:1 for best performance.
• Solution: Use a gearbox or larger inertia servo motor if mismatch occurs.

Incremental Encoder: Outputs relative position; requires homing after power-up.

Absolute Encoder: Remembers absolute position even after power loss; no homing required.

Which to choose?

• Use incremental if homing is simple and cost is critical.
• Use absolute if downtime and precision are critical (e.g., robotics, multi-axis systems).

Power Cables: Can be extended but require thicker gauge to minimize voltage drop.

Encoder Cables: Very sensitive; avoid extension beyond 20m. Use shielded twisted pair and consider amplifiers/filters if necessary.

Yes. Proper grounding ensures safety and minimizes interference.

• Motor PE terminal → connect to driver PE with short, thick wire.

• Driver PE terminal → connect to cabinet ground bar.

• Cable shielding → ground at driver side only to avoid ground loops.

• High Rigidity: Fast response, resists load disturbances, but risk of oscillation.
• Low Rigidity: Smooth operation but weaker disturbance resistance.

Adjustment: Increase loop gains gradually until optimal response is achieved without vibration. Use driver’s auto-gain tuning if available.

Cause: The servo continuously applies small corrective currents to hold position (“servo noise”).

Fixes:

Lower loop gain settings.

Apply notch filters for resonance frequencies.

Increase “in-position tolerance” so the system doesn’t over-correct.

Compact servo motors often used in RC models, drones, and educational robotics.

Check the product manual for full servo motor specifications, including servo motor pin details, working principle, and wiring diagrams.