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Siemens SINUMERIK Controller
Servo/Axis · Intermediate · 30-60 minutes
Siemens 840D 61244 - Channel block: Pitch change causing
The specified lead change causes a reversal of the thread direction. Alarm triggered by following cycle: CYCLE99
61244
Siemens 840D 61244 - Channel block: Pitch change causing
Channel block: Pitch change causing
The specified lead change causes a reversal of the thread direction. Alarm triggered by following cycle: CYCLE99
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Common Causes
- Pitch value change between successive thread blocks that reverses lead direction
- Incorrect CYCLE99 parameters causing negative pitch progression
- G-code logic error where pitch decrements below zero or changes sign
- Incompatible thread direction specification in consecutive cycles
Troubleshooting Steps
- 1Review the CYCLE99 thread parameters in the NC program for channel %1, block %2 - verify pitch values are monotonic and do not reverse direction
- 2Check that all pitch change commands maintain consistent thread lead direction throughout the cycle sequence
- 3Verify CYCLE99 syntax and parameter order match machine documentation; confirm pitch increment/decrement values are logical
- 4Modify the NC program to eliminate the pitch reversal by adjusting thread profile or splitting into separate non-reversing cycles if multi-directional threading is required
- 5Simulate or dry-run the corrected program to confirm alarm does not reoccur
Seeing Multiple Alarms?
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