Code 7020: Compile cycle alarm number has not been defined
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical Compile cycle alarm number has not been defined 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
Definitions: The alarm ID used by the compile cycle manufacturer is not known to the system. This was not allocated when the compile cycle alarms were generated. Reaction: Alarm display. Remedy: The alarm can have 2 possible causes: - The alarm number has not been defined. A definition must still be made. - The call parameter used is not the same as the one transferred by the NCK. Program Continuation: Clear alarm with the Delete key or NC START.
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 7020 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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