Code M01-1029: Variable speed thread disabled
Issue Description & Safety Warning
The Mitsubishi M800/M80 CNC has triggered a critical Variable speed thread disabled 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
Details "#8045 Varying spd thread" has been set to "1" to issue a variable speed thread cut command even though the function is not included in the specifications. A variable speed thread cut command has been given while the feed axis acce leration/deceleration type is soft acceleration/deceleration. A variable speed thread cut command has been given while the spindle encoder signal is not sent via serial input. A variable speed thread cut command has been giv en even though the spindle, lead axis or plane com- posing axes are controlled by dr ive other than MDS-E Series. The spindle intended for thread cutting is executing synchronous tapping, spindle synchronization, guide bushing spindle synchronization or spindle/C axis control. Remedy Check the specifications. Check the parameters. Check the program. Check the Encoder selection signal (R register).
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 M01-1029 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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