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Siemens SINUMERIK Controller
Spindle · Intermediate · 30-120 minutes
Siemens 840D 20055 - Channel master spindle not present in JOG mode
Alarm 20055 occurs when attempting JOG mode traversal with revolutional feed (feed per revolution) on a channel axis, but no master spindle reference has been configured. The NCK cannot calculate the required feedrate without a defined master spindle to derive actual speed feedback, preventing safe axis motion.
20055
Siemens 840D 20055 - Channel master spindle not present in JOG mode
Channel master spindle not present in JOG mode
Siemens SINUMERIK 840D alarm 20055: Channel master spindle not present in JOG mode. 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 20055 occurs when attempting JOG mode traversal with revolutional feed (feed per revolution) on a channel axis, but no master spindle reference has been configured. The NCK cannot calculate the required feedrate without a defined master spindle to derive actual speed feedback, preventing safe axis motion.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Access Siemens HMI Diagnostics > Parameters > Machine Data. Navigate to MD20050 (Master Spindle Number for Channel). Verify the parameter is assigned to a valid spindle number (typically 1 or higher).
Do not modify while machine is in automatic cycle mode.
- 2
Cross-reference the assigned spindle number against MD10200 (Spindle Type) to confirm the spindle is configured as active in the NCK. Spindle must support speed feedback for revolutional feed.
- 3
Verify MD20000 (Channel Number) and MD20010 (Channel Type) confirm the channel exists and is configured for multi-axis simultaneous operation. Inactive or unconfigured channels cannot use JOG revolutional feed.
- 4
Save machine data (Ctrl+S) and perform warm restart (Cycle Start > Machine > Restart) to activate parameter changes. Retry JOG mode with revolutional feed.
A cold restart may be required if warm restart does not apply changes.
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