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Siemens SINUMERIK Controller
Program/G-code · Intermediate · 30-120 minutes
Siemens 840D 104255 - Function Current location not valid for buffer
Alarm 104255 occurs when attempting to use the 'Current location' function while the machine buffer state is incompatible with this operation. This typically happens when trying to restart from current position during buffered look-ahead execution, during certain program interruptions, or when the interpreter is in a state that prevents accurate position capture for restart purposes.
104255
Siemens 840D 104255 - Function Current location not valid for buffer
Function Current location not valid for buffer
Siemens SINUMERIK operator message 104255: Function Current location not valid for buffer. This is an informational message from the SINUMERIK control indicating a system status or operation result that may require operator action.
Root Cause Summary
Alarm 104255 occurs when attempting to use the 'Current location' function while the machine buffer state is incompatible with this operation. This typically happens when trying to restart from current position during buffered look-ahead execution, during certain program interruptions, or when the interpreter is in a state that prevents accurate position capture for restart purposes.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Press RESET or cycle mode selector to clear the current program buffer and stop look-ahead processing.
- 2
Allow all buffered movements to complete or acknowledge the program stop completely before attempting position capture.
- 3
Use 'Reposition' function instead if you need to restart after an interruption with buffered blocks.
Reposition function may require manual verification of tool position before restart
- 4
If problem persists, reduce look-ahead buffer depth via MD10711 (NUM_BLOCKS_IN_PREP) to 5-10 blocks for critical restart sections.
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