Code 201036: <location>ACX: Parameter back-up file missing
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical <location>ACX: Parameter back-up file missing 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
Message value: %1 Drive object: All objects Reaction: A_INFEED: NONE (OFF2) SERVO: NONE (OFF1, OFF2, OFF3) VECTOR: NONE (OFF1, OFF2, OFF3) Acknowledge: IMMEDIATELY Cause: When downloading the device parameterization, a par ameter back-up file asso ciated with a drive object cannot be found. Neither a PSxxxyyy.ACX, a PSxxxyyy.NEW nor a PSxxxyyy.BAK parameter back-up file exists on the CompactFlash card for this drive object. Fault value (r0949, interpret hexadecimal): Byte 1: yyy in the file name PSxxxyyy.ACX yyy = 000 --> consistency back-up file yyy = 001... 062 --> drive object number yyy = 099 --> PROFIBUS parameter back-up file Byte 2, 3, 4: Only for internal Siemens troubleshooting. Remedy: If you have saved the project data using the commiss ioning software, carry out a new download for your project. Save using the function "Copy RAM to ROM" or with p0977 = 1 so that all of the parameter files are again completely written to the CompactFlash card. If you have not saved the project data, then first commissioning of the system has to be carried out again.
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 201036 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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