Code 120307: File %1 cannot be opened for the editor because it is selected in channel %2 for execution by external sources.
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical File %1 cannot be opened for the editor because it is selected in channel %2 for execution by external sources. 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 = Program name with path %2 = Channel number Definitions: -Reaction: Alarm display. Remedy: A different program on the NCU or for executio n from external sources has to be selected. The alarm disappears automatically as soon as a pr ogram is edited or simulated in the program area. The alarm can also be acknow ledged manually via diagnostics. Program Continuation: Internal
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 120307 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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