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Siemens SINUMERIK Controller
Program/G-code · Intermediate · 30-120 minutes
Siemens 840D 104120 - PA: Error on writing JOG feed value
Alarm 104120 occurs when the system fails to write or accept a JOG feed value, typically due to invalid parameter entries, protected machine data settings, or incorrect access levels. This is most commonly caused by attempting to set JOG feedrates outside permitted ranges defined in machine data or lacking proper authorization to modify JOG parameters.
104120
Siemens 840D 104120 - PA: Error on writing JOG feed value
PA: Error on writing JOG feed value
Siemens SINUMERIK alarm 104120: PA: Error on writing JOG feed value. This alarm indicates an error condition in the NC program or control configuration that must be resolved before the operation can continue.
Root Cause Summary
Alarm 104120 occurs when the system fails to write or accept a JOG feed value, typically due to invalid parameter entries, protected machine data settings, or incorrect access levels. This is most commonly caused by attempting to set JOG feedrates outside permitted ranges defined in machine data or lacking proper authorization to modify JOG parameters.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Access Service mode and check machine data MD11300 (JOG_VELO) and MD11310 (JOG_VELO_RAPID) for defined minimum and maximum JOG feed limits per axis.
- 2
Review the JOG feed value being set in the HMI or NC program and verify it falls within the range specified in MD11300/MD11310.
- 3
If the desired feed value is legitimate, adjust MD11300 or MD11310 limits accordingly with machine manufacturer's approval.
Changing maximum JOG velocities may affect machine safety. Consult machine documentation and perform risk assessment.
- 4
Perform a control power cycle (NC Start) and test JOG operation with corrected feed values.
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Always verify with your machine manual or a certified technician before performing service procedures.