Code V01-020: Smart Safety Observation Error
Issue Description & Safety Warning
The Mitsubishi M800/M80 CNC has triggered a critical Smart Safety Observation Error alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
The command/FB speed has failed to decelerate to thesafely-limited speed(*) or lower within a period of SLS deceleration observation time (set by parameter) after start of SLS observation. The screen displays the name of axis of this error. (*)Safely-limited speed = SLS speed tolerance x SLS speed override / 100 Remedy This error can be cancelled by the safety reset signal while motor speed is under SLS limit. If the SLS speed tolerance or SLS speed override (setby parameter) is lower than the assumption, change the parameter setting and turn OFF and ON the power. If the SLS deceleration observation time (set by parameter) is shorter than the assumption, change the parameter setting. SLP position error 0003 Axis name
Source: Mitsubishi M800/M80/E80 Series Alarm/Parameter Manual (IB-1501279)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Mitsubishi M800/M80 CNC Alarms
Mitsubishi controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code V01-020 on the M800/M80 CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Mitsubishi's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 722 Mitsubishi M800/M80 CNC codes.
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