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Siemens SINUMERIK Controller
Spindle · Intermediate · 30-120 minutes
Siemens 10640 - [up to SW 3.x only] Channel block spindle cannot stop during
Alarm 10640 occurs when a spindle stop command (via Reset or S0) is issued while the spindle is in gear-change oscillation mode, waiting for PLC acknowledgement that the gear change (DBX 16.3 in DB 31-48) has completed. The NCK cannot interrupt this synchronized gear-change sequence until the PLC confirms the mechanical gear change is finished.
10640
Siemens 10640 - [up to SW 3.x only] Channel block spindle cannot stop during
[up to SW 3.x only] Channel block spindle cannot stop during
The spindle is in the oscillating mode for a gear change and is waiting for the PLC acknowledgement stating that the gear change has taken place (interface signal: Gear has changed DB 31 - 48, DBX 16.3). During this phase spindle stop is not possible, initiated by Reset (DB 21 - 28, DBX 7.7) or NC Stop axes plus spindle (DB 21 - 28, DBX 7.4) Control reaction: Alarm display.
Root Cause Summary
Alarm 10640 occurs when a spindle stop command (via Reset or S0) is issued while the spindle is in gear-change oscillation mode, waiting for PLC acknowledgement that the gear change (DBX 16.3 in DB 31-48) has completed. The NCK cannot interrupt this synchronized gear-change sequence until the PLC confirms the mechanical gear change is finished.
Safety
- Spindle hazard: ensure the spindle is at standstill before working near it; follow lockout/tagout procedures.
Causes and Fixes
- 1
Access PLC diagnostics via HMI > Diagnostics > PLC > Watch Variables. Monitor DB 31-48, DBX 16.3 state before and after gear-change command.
Ensure you have sufficient PLC access rights; some systems restrict real-time watch access.
- 2
Verify mechanical gear-change actuator (solenoid/servo) is functioning by observing position sensors in the PLC. Check if the actual gear position matches the commanded gear in the PLC logic.
Manually engage gears only if machine is safely locked out; do not override without confirming mechanical state.
- 3
Review the PLC program (OB/FB for gear change) to confirm DBX 16.3 is set immediately upon successful mechanical engagement detection. Cross-reference with MD 32200 (Spindle_Gear_Change_Mode) to ensure gear-change synchronization is enabled.
- 4
If signal is stuck, reset the PLC by cycling machine power or executing a controlled Emergency Stop followed by Manual Mode reset. Verify sensor wiring and connector integrity at the servo/solenoid control module.
E-Stop resets all spindle states; ensure full machine restart is acceptable in your production environment.
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