Code 4076: %1 Machine data could not be changed with permission level %2
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical %1 Machine data could not be changed with permission level %2 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 = Number of MDs %2 = Preset access authorization Definitions: On executing a TOA file or when writing data from the part program an attempt has been made to write data with a higher protection level than the access authorization currently set in the control. The data in question have not been written and program executi on is continued without hindrance. This alarm is issued on acknowledging alarm 4075. It can be cleared only with Power ON. Reaction: NC Start disable in this channel. Alarm display. Remedy: Please inform the authorized personnel/service depar tment. Set the required access level by means of keyswitch or password entry or delete the mach ine data concerned from the MD file/part program. Program Continuation: Switch control OFF - ON.
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 4076 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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