Technical Guide
Mitsubishi MR-J4 Servo Alarm AL.52 Troubleshooting & Auto-Tuning Machine Resonance Filters
SP Automation Engineering Team
1 min read
Alarm AL.52 (Error Excessive) on Mitsubishi MR-J4 servo drives triggers when the accumulated position error in the deviation counter exceeds the threshold set in parameters `PC01` or `PC02`. This protective shutdown prevents runaway collisions when actual motor feedback lags behind position commands.
Diagnostic Matrix & Solutions
| Potential Root Cause | Diagnostic Verification | Corrective Action |
|---|---|---|
| Mechanical binding in ballscrew or guide | Rotate ballscrew manually with servo unpowered | Lubricate, inspect gibs, or replace thrust bearings |
| High-frequency mechanical resonance | Listen for audible squealing during rapid motion | Enable auto notch filters via MR Configurator2 |
| Excessive acceleration rate | Monitor peak current during speed changes | Extend accel/decel ramps or increase torque limit clamp |