What causes Siemens SINUMERIK alarm 4012?

Machine data was changed requiring acknowledgment or power cycle. System configuration change notification. Commissioning or service operation generated this notice. Axis or drive configuration change affecting machine data.

How do I fix Siemens SINUMERIK alarm 4012?

1. Read the complete notice text on the SINUMERIK screen. 2. If a power cycle is indicated, perform a controlled machine power off and restart. 3. If machine data backup is indicated, save the current machine data. 4. Acknowledge the notice and verify the system is operating correctly after the change. 5. Consult the machine commissioning engineer if the notice is unexpected.

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Siemens SINUMERIK Controller

System · Intermediate · 30-120 minutes

Alarm 4012

Siemens 840D 4012 - Invalid identifier used in machine data

Alarm 4012 occurs when an invalid axis identifier is referenced in machine data (MD) or setup data (SD) parameters. The SINUMERIK control expects properly formatted identifiers (AX1-AXn for machine axes, N1AX1-NnAXm for NCU link axes, or C1S1-CnSm for container axes) but receives a malformed or non-existent identifier instead.

Siemens SINUMERIKSystemIntermediate30-120 minutes

4012

Siemens 840D 4012 - Invalid identifier used in machine data

Invalid identifier used in machine data

Root Cause Summary

Alarm 4012 occurs when an invalid axis identifier is referenced in machine data (MD) or setup data (SD) parameters. The SINUMERIK control expects properly formatted identifiers (AX1-AXn for machine axes, N1AX1-NnAXm for NCU link axes, or C1S1-CnSm for container axes) but receives a malformed or non-existent identifier instead.

Safety

Refer to Siemens documentation
Ensure qualified technician performs repairs

Causes and Fixes

1
Access Siemens SINUMERIK Operate interface and navigate to 'Diagnostics > Alarms' to capture the full alarm text including the %1[%2] substitution parameters showing the exact invalid identifier and affected MD/SD number.
2
Open the machine data editor (Menu > Machine Data > MD) and locate the parameter number indicated in the alarm. Verify the axis identifier field follows valid syntax: AX1 through AXn (where n is configured axis count), or N#AX# / C#S# format if using link/container axes.
Do not modify MD parameters while CNC is in AUTO mode; switch to MANUAL or disable NC/PLC first.
3
Cross-reference configured axes in MD 1004 (RESET axis index table) and MD 1008 (axis identifier table) to ensure the referenced identifier exists and matches the machine configuration. For NCU link axes, verify MD 32100+ (NCU link parameters) are properly configured.
4
Correct the axis identifier to match valid format (e.g., change 'AX0' to 'AX1', 'N1AX1' to 'N1AX2', etc.) and save the machine data. Perform a warm restart (RESET) to reload MD into NCK memory.

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