Code 126-011F: Safety not ensured
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical Safety not ensured 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
[Cause of error] Configuration data relevant to safety functions of the system were changed and have not been accepted yet. [Error correction] Please pay attention to the following information about parameter sets in which configuration data was changed. Perform an acceptance test of the functional safety for this system according to the guidelines of the OEM when the respective parameter sets are active. Shut the system down; while doing so, confirm that the functional safety was successfully tested and accepted.
Source: HEIDENHAIN NC Error Messages — TNC7/640/620/320/128, CNC PILOT 640, MANUALplus 620 (10/2023)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Heidenhain TNC Series CNC Alarms
Heidenhain controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 126-011F on the TNC Series CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Heidenhain's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 4497 Heidenhain TNC Series CNC codes.
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