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Check Encoder Cable Connections

Power down machine and inspect Y-axis encoder cable connections at motor and drive. Look for loose, corroded, or damaged pins on the encoder connector.

Always power down before checking electrical connections

Verify Encoder Parameters

Access SETTING menu, check parameter 72 (Y-Axis Encoder Lines) matches motor specification. Typical values are 1024, 2048, or 4096 lines.

Parameter 72 must exactly match the encoder specification or servo faults will occur

Test Encoder Signal Quality

In CURRENT COMMANDS menu, manually jog Y-axis slowly and observe position feedback. Erratic or jumping position values indicate encoder problems.

Inspect Encoder for Physical Damage

Remove Y-axis motor cover and visually inspect encoder disc for cracks, contamination, or misalignment. Check encoder housing for damage.

Check Servo Drive Status LEDs

Open electrical cabinet and locate Y-axis servo drive module. Check status LEDs - solid green indicates normal operation, red or flashing indicates fault condition.

High voltage present - qualified personnel only

Verify Drive Temperature

Check if servo drive heat sink is excessively hot. Ensure cooling fans are operating and air filters are clean. Overheating causes thermal shutdown.

Servo drives should be warm but not too hot to touch briefly

Test Drive Output Voltage

Using appropriate test equipment, measure servo drive output voltage to Y-axis motor. Should show balanced 3-phase AC voltage when commanded to move.

Check Drive Enable Signal

Verify 24VDC enable signal is present at servo drive input. Loss of enable signal will cause servo fault condition.

Check Following Error Parameters

In SETTING menu, verify parameter 70 (Max Following Error) is set appropriately, typically 0.005-0.020 inches. Parameter 71 sets the time limit.

Tighter following error limits provide better accuracy but may cause nuisance faults

Test Y-Axis Mechanical Movement

Manually move Y-axis (power off) to check for binding, excessive friction, or mechanical obstructions. Movement should be smooth throughout travel.

Verify Servo Gain Settings

Check parameters 74-76 (Y-axis servo gains). Incorrect gains cause poor servo response and following errors. Use factory default values as starting point.

Monitor Following Error in Real-Time

In CURRENT COMMANDS menu, observe following error during slow manual jogs. Values should remain well below parameter 70 setting during normal movement.

Check Motor Power Connections

Inspect Y-axis motor power cable connections at both motor and servo drive. Look for loose, burned, or corroded connections on all three phases.

Disconnect power before checking motor connections

Test Motor Winding Resistance

Using ohmmeter, measure resistance between motor phases (U-V, V-W, W-U). Readings should be balanced, typically 1-10 ohms depending on motor size.

Check Motor Insulation

Test insulation resistance from each motor winding to motor frame/ground. Should read >1 megohm. Low readings indicate winding insulation breakdown.

Inspect Motor for Physical Damage

Check motor housing for signs of overheating, contamination, or physical damage. Verify motor mounting is secure and shaft rotates freely.