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Siemens SINUMERIK Controller
Program/G-code · Intermediate · 15-45 minutes
Siemens 12250 - Block nested macro not possible
SINUMERIK alarm 12250 occurs when the TRC (Tool Radius Compensation) calculation engine cannot resolve valid compensated tool paths during multi-block lookahead processing. The controller's geometric calculation fails due to impossible intersection conditions, missing tool data, or program blocks that create undefined compensation vectors.
12250
Siemens 12250 - Block nested macro not possible
Block nested macro not possible
Siemens SINUMERIK alarm 12250: Block nested macro not possible. Detailed remedy is being verified against the current Siemens diagnostics manual.
Root Cause Summary
SINUMERIK alarm 12250 occurs when the TRC (Tool Radius Compensation) calculation engine cannot resolve valid compensated tool paths during multi-block lookahead processing. The controller's geometric calculation fails due to impossible intersection conditions, missing tool data, or program blocks that create undefined compensation vectors.
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
Check Tool Offset Table
Navigate to Parameters > Tool Management > Tool Data and verify the active tool number has valid radius value in geometry field.
Use MD18118 TOOL_DATA_CHANGE_MODE to enable online tool data modification
- 2
Verify Active Tool Selection
Check current tool number matches programmed T-word and confirm tool is properly measured with valid wear offset values.
Never enter compensation mode with unmeasured tools
- 3
Test Tool Data Integrity
Execute a simple G41 move in MDI mode with known good geometry to isolate tool data corruption from program issues.
Call a technician if:
- ·Persistent alarms after tool data verification
- ·Suspected TRC parameter corruption
- ·Hardware-related compensation calculation failures
Prevention
- Always verify tool measurements before TRC activation
- Use SINUMERIK Simulate for complex contour validation
- Maintain consistent approach/retract moves for TRC entry/exit
Common Mistakes
- Activating TRC with zero tool radius
- Programming sharp inside corners without geometric analysis
- Mixing coordinate transformations with active tool compensation
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