What causes Siemens SINUMERIK alarm 26012?

Parameter or machine data configuration error. Hardware fault on the NC or drive component. Part program error or illegal command. Communication fault between NC and drive or I/O modules. Software or firmware error requiring system restart.

How do I fix Siemens SINUMERIK alarm 26012?

1. Note the complete alarm text including any axis, channel, or block number values. 2. Check for related alarms active simultaneously in the SINUMERIK alarm list. 3. Power cycle the machine to clear transient faults. 4. Review the SINUMERIK machine data for parameters related to the alarm. 5. Consult the Siemens SINUMERIK alarm manual for alarm 26012 detailed remedy.

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Siemens SINUMERIK Controller

Overtravel/Limit · Intermediate · 30-120 minutes

Alarm 26012

Siemens 840D 26012 - Axis QEC: feed forward control not active

Alarm 26012 fires when the quadrant error compensation (QEC) algorithm detects that feedforward control is inactive on the specified axis, preventing proper quadrant error criterion evaluation. The feedforward control (Vorsteuerung) must be enabled via MD parameters to allow QEC functionality and eliminate dead-band related positioning errors.

Siemens SINUMERIKOvertravel/LimitIntermediate30-120 minutes

26012

Siemens 840D 26012 - Axis QEC: feed forward control not active

Axis QEC: feed forward control not active

Root Cause Summary

Alarm 26012 fires when the quadrant error compensation (QEC) algorithm detects that feedforward control is inactive on the specified axis, preventing proper quadrant error criterion evaluation. The feedforward control (Vorsteuerung) must be enabled via MD parameters to allow QEC functionality and eliminate dead-band related positioning errors.

Safety

Refer to Siemens documentation
Ensure qualified technician performs repairs

Causes and Fixes

1
Navigate to Diagnostics > Machine Data (MD) and search for the affected axis feedforward parameters: MD 32100 AXCONF_MACHAX_INPUT_OFFSET and MD 32110 (AXCONF_MEASURE_INPUT_OFFSET) for the axis number in %1.
2
Verify MD 32100 is set to a non-zero value matching the physical feedforward transducer configuration. If set to 0, change to 1 (external transducer) or 2 (integrated transducer) per your axis hardware.
Incorrect feedforward input offset values will cause incorrect QEC criterion evaluation.
3
Check MD 32114 (AXCONF_FEEDFORWARD_GAIN) is enabled (typically set to 1.0 or higher). A value of 0 disables feedforward regardless of other settings.
4
Activate the changes via Diagnostics > Control Panel > Shutdown/Warmstart. If alarm persists, perform a full PLC download from Diagnostics > Program > Download.

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