Code 231-E01F: CC%2 SPLC program requests invalid change of
Issue Description & Safety Warning
The Heidenhain TNC Series CNC has triggered a critical CC%2 SPLC program requests invalid change of 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
operating mode [Cause of error] - The SPLC program requests an illegal change of the safe operating mode via the date ApiToSafety.PP_GenSOM. [Error correction] - Check the SPLC program. The following changes are not permitted: S_MODE_SOM_2 -> S_MODE_SOM_4 S_MODE_SOM_3 -> S_MODE_SOM_4 S_MODE_SOM_4 -> S_MODE_SOM_2 S_MODE_SOM_4 -> S_MODE_SOM_3 - Inform your service agency
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 231-E01F 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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