What causes Siemens SINUMERIK alarm 104012?

Normal control operation generated this status message. User action or program command triggered this notification. System configuration or commissioning activity produced this message. Machine data or parameter change created this notification.

How do I fix Siemens SINUMERIK alarm 104012?

1. Read the complete message text on the SINUMERIK screen — note any parameter values shown. 2. If action is required, follow the instructions in the message. 3. Acknowledge the message on the operator panel to continue operation. 4. Consult the Siemens SINUMERIK alarm documentation for message 104012 if clarification is needed. 5. If this message appears unexpectedly, review recent parameter or configuration changes.

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Siemens SINUMERIK Controller

Spindle · Intermediate · 30-120 minutes

Alarm 104012

Siemens 840D 104012 - No master spindle available

Alarm 104012 fires when the NCK attempts to execute a spindle function (M3, M4, M5, or spindle speed S-word) but no master spindle has been configured in machine data. This occurs because MD18082 (SpindleType) is either not set, set to 0 (disabled), or the spindle assignment in MD18000 series parameters is incomplete, preventing the control from identifying a valid spindle axis.

Siemens SINUMERIKSpindleIntermediate30-120 minutes

104012

Siemens 840D 104012 - No master spindle available

No master spindle available

Root Cause Summary

Alarm 104012 fires when the NCK attempts to execute a spindle function (M3, M4, M5, or spindle speed S-word) but no master spindle has been configured in machine data. This occurs because MD18082 (SpindleType) is either not set, set to 0 (disabled), or the spindle assignment in MD18000 series parameters is incomplete, preventing the control from identifying a valid spindle axis.

Safety

Refer to Siemens documentation
Ensure qualified technician performs repairs

Causes and Fixes

1
Access Siemens HMI > Diagnosis > Machine Data. Navigate to MD18082 (SpindleType) and verify it is set to 1 (rotary spindle) or 2 (linear spindle), not 0.
Do not modify while program is active; access offline or during machine RESET state.
2
Check MD18000 (SpindleAxisAssignment) to confirm a valid axis name (e.g., 'S', 'C') is assigned as the master spindle. Verify the axis name matches a configured axis in MD1008.
3
Confirm MD18010 (SpindleIsModulated) is set appropriately (0=modulated speed, 1=direct speed). Verify MD18020 (SpindleVmax) and MD18030 (SpindleAmax) contain valid, non-zero values in rpm and rpm/s respectively.
4
Save machine data changes and perform a warm restart (POWER ON > OFF > ON) or use SINUMERIK > Service > Restart NCK to reload parameters.
Warm restart clears transient states; cold restart may be required if alarm persists.

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