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Siemens SINUMERIK Controller
Spindle · Intermediate · 30-120 minutes
Siemens 840D 21600 - Monitoring for ESR active
Alarm 21600 indicates that Electronic Spindle Regulation (ESR) monitoring has detected an active condition that requires attention. This alarm fires when the spindle control system identifies that ESR functions are engaged but system conditions or parameter settings conflict with safe spindle operation.
21600
Siemens 840D 21600 - Monitoring for ESR active
Monitoring for ESR active
Siemens SINUMERIK 840D alarm 21600: Monitoring for ESR active. This alarm indicates a program or channel-level error on the SINUMERIK control. The part program or machine function cannot be executed as commanded.
Root Cause Summary
Alarm 21600 indicates that Electronic Spindle Regulation (ESR) monitoring has detected an active condition that requires attention. This alarm fires when the spindle control system identifies that ESR functions are engaged but system conditions or parameter settings conflict with safe spindle operation.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Navigate to Diagnostics > Spindle in the 840D control panel and verify MD21210 (ESR enable) status. Check if ESR should be active for this operation mode.
- 2
Verify MD21000 (Spindle enable) and MD21001 (Spindle speed range select) are consistent with the current NC program requirements. Confirm spindle speed setpoint (SD21010) is initialized.
Do not force disable ESR without understanding program requirements—this may cause loss of spindle synchronization.
- 3
Check Machine Data MD21200 (ESR monitoring sensitivity) and MD21201 (ESR deviation threshold) to ensure thresholds are appropriate for your spindle load characteristics.
- 4
Reset the spindle by cycling power or issuing a spindle RESET command in the PLC interface, then re-run the NC program startup sequence.
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Always verify with your machine manual or a certified technician before performing service procedures.