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Siemens SINUMERIK Controller
Program/G-code · Intermediate · 30-120 minutes
Siemens 840D 101635 - Write access only in start-up state (p10 unequal 0).
Alarm 101635 occurs when attempting to modify machine data or system parameters while the control is in an operational state (power-on parameter P10 equals 0). Write access to certain protected parameters and machine data is only permitted during startup mode (P10 not equal to 0) to prevent unsafe modifications during machine operation.
101635
Siemens 840D 101635 - Write access only in start-up state (p10 unequal 0).
Write access only in start-up state (p10 unequal 0).
Siemens SINUMERIK operator message 101635: Write access only in start-up state (p10 unequal 0). This is an informational message from the SINUMERIK control indicating a system status or operation result that may require operator action.
Root Cause Summary
Alarm 101635 occurs when attempting to modify machine data or system parameters while the control is in an operational state (power-on parameter P10 equals 0). Write access to certain protected parameters and machine data is only permitted during startup mode (P10 not equal to 0) to prevent unsafe modifications during machine operation.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Navigate to HMI Commissioning or Service menu and check current system state indicator to confirm P10 value is 0 (operational mode).
- 2
Set power-on parameter P10 to startup level (P10=1 for standard startup, P10=6 for manufacturer level) via HMI Service menu → Startup → Set Startup Mode.
Setting startup mode may require password authentication depending on access level configured.
- 3
Make required machine data or parameter changes while in startup mode.
Document all changes made. Incorrect parameter modifications can cause machine malfunction or safety issues.
- 4
Exit startup mode by setting P10=0 and perform a complete NCK restart (Power On Reset) to activate changes.
All axes will be de-referenced after restart. Re-homing will be required before operation.
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Always verify with your machine manual or a certified technician before performing service procedures.