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Siemens SINUMERIK Controller
Spindle · Intermediate · 30-120 minutes
Siemens 840D 16105 - Channel block spindle cannot be assigned
Alarm 16105 fires when an NC program references a spindle number that lacks a corresponding entry in the spindle assignment table ($SC_SPIND_ASSIGN_TAB[]), preventing the NCK from mapping the logical spindle to a physical axis. This occurs due to misconfiguration in the machine data or improper spindle indexing during program execution.
16105
Siemens 840D 16105 - Channel block spindle cannot be assigned
Channel block spindle cannot be assigned
Siemens SINUMERIK 840D alarm 16105: Channel block spindle cannot be assigned. This alarm indicates a program or channel-level error on the SINUMERIK control. The part program or machine function cannot be executed as commanded.
Root Cause Summary
Alarm 16105 fires when an NC program references a spindle number that lacks a corresponding entry in the spindle assignment table ($SC_SPIND_ASSIGN_TAB[]), preventing the NCK from mapping the logical spindle to a physical axis. This occurs due to misconfiguration in the machine data or improper spindle indexing during program execution.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Access Siemens HMI menu: Maintenance > Machine Data > Spindle Parameters. Locate $SC_SPIND_ASSIGN_TAB[] and verify all spindle numbers referenced in your NC program have corresponding entries.
- 2
Cross-reference the spindle number in the alarm message (spindle %3) with the table index. For example, if alarm shows spindle 2, check that $SC_SPIND_ASSIGN_TAB[2] contains a valid axis number (typically 1-9).
Verify axis exists in MD 20050 ($MC_AXCONF_MACHAX_TAB) before assigning in spindle table.
- 3
If entry is missing, add it by editing the parameter. Set $SC_SPIND_ASSIGN_TAB[spindle_number] = axis_number (where axis_number corresponds to a configured machine axis).
- 4
Save changes via HMI, perform a complete NCK reset (Siemens menu: Service > Reset), and retry the program.
Resetting NCK will interrupt active machining; perform during safe machine state.
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Always verify with your machine manual or a certified technician before performing service procedures.