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Siemens SINUMERIK Controller
Tool Changer · Intermediate · 30-120 minutes
Siemens 6453 - Block tool change not possible. No assignment between toolholder/
Alarm 6453 fires when the NCK attempts a tool change but cannot locate a valid mapping between the requested tool holder/spindle number and a physical buffer magazine location. This occurs because the tool changer configuration lacks the required assignment in the machine data or tool magazine table, preventing the PLC from executing the tool change motion.
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Siemens 6453 - Block tool change not possible. No assignment between toolholder/
Block tool change not possible. No assignment between toolholder/
The desired tool change is not possible. No relation has been defined between the toolholder/spindle number and the buffer magazine location (Location No.) Control reaction: Correction block is reorganized. Interface signals are set. Alarm display. Alarms.
Root Cause Summary
Alarm 6453 fires when the NCK attempts a tool change but cannot locate a valid mapping between the requested tool holder/spindle number and a physical buffer magazine location. This occurs because the tool changer configuration lacks the required assignment in the machine data or tool magazine table, preventing the PLC from executing the tool change motion.
Safety
- Only qualified personnel should diagnose and clear control alarms; follow the machine builder's safety procedures and lockout/tagout where hardware work is required.
Causes and Fixes
- 1
Access Siemens HMI > Diagnostics > Parameters menu. Navigate to Machine Data (MD) 28100 series and verify MD 28110 'Tool_Magazine_Number' and MD 28120 'Tool_Magazine_Type' are correctly configured for your spindle/toolholder combination.
Editing machine data requires administrator/service credentials and will require a machine reset to apply changes.
- 2
In the NCK/PLC program, check the tool magazine table (typically accessed via HMI > Tool Management > Magazine Configuration). Confirm that each tool holder slot has a valid 'Location Number' assignment and that the spindle index matches the tool change command in the NC block.
- 3
Cross-reference the tool number in the active NC program (e.g., T01 M06) against the Tool Magazine Editor. Verify the tool exists in the magazine table with a defined location and that MD 28100 'Tool_Changer_Type' matches your physical equipment.
- 4
Reset the machine data cache by performing a Warm Reset (Ctrl+Shift+F5 on HMI or via Service > System > Reset). Re-run the tool change command to confirm the assignment is now active.
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