Code 27012: Axis %1 safe end position exceeded
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical Axis %1 safe end position exceeded 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
Parameters: %1 = Axis number Definitions: The axis has exceeded the li mit position entered in MD $MA_SAFE_POS_LIMT_PLUS or MD $MA_SAFE_POS_LIMIT_MINUS. Reaction: NC Start disable in this channel. Interface signals are set. Alarm display. NC Stop on alarm. Stop the axis with STOP C,D or E, depending on the configuration in MD $MA_SAFE_POS_STOP_MODE. Remedy: If no obvious operator error occurred: Check the input value of the machine data and check the SGEs: was the correct one of 2 limit positions selected ? If the MDs and SGEs are o.k., check the machine for any damage and rectify it. Program Continuation: Clear alarm with the RESET key. Restart part program Remove the user agreement for this axis. Then press the RESET key causing the program to be aborted and the alarm to be deleted. Traverse the axis in JOG mode to the valid traversing range. After fault correction of the NC program and an axis pos ition check, the user agreement can be set again and the program can be restarted.
Source: SINUMERIK 840D sl / 840Di sl / SINAMICS S120 Diagnostics Manual (DAsl, 03/2009)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Siemens SINUMERIK 840D CNC Alarms
Siemens controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 27012 on the SINUMERIK 840D CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Siemens's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 4014 Siemens SINUMERIK 840D CNC codes.
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