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Siemens SINUMERIK Controller
Program/G-code · Intermediate · 30-120 minutes
Siemens 840D 104242 - Illegal location number
Alarm 104242 occurs when the NC program references an invalid or non-existent location number in a positioning or tool management command. This typically happens when attempting to access a magazine position, tool pocket, or buffer location that is outside the configured range or not defined in the machine data.
104242
Siemens 840D 104242 - Illegal location number
Illegal location number
Siemens SINUMERIK alarm 104242: Illegal location number. This alarm indicates an error condition in the NC program or control configuration that must be resolved before the operation can continue.
Root Cause Summary
Alarm 104242 occurs when the NC program references an invalid or non-existent location number in a positioning or tool management command. This typically happens when attempting to access a magazine position, tool pocket, or buffer location that is outside the configured range or not defined in the machine data.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Review the NC program line that triggered the alarm and identify the location number being referenced (check T-number or magazine position call).
- 2
Access machine data MD18100 $MN_MM_NUM_MAGAZINE and verify the number of configured magazines, then check MD18110 $MN_MM_NUM_MAGAZINE_LOCATION for maximum pocket numbers per magazine.
- 3
Compare the program's referenced location number against the valid range (1 to maximum configured locations). Verify tool management configuration in Settings > Tool Management.
- 4
Correct the NC program to use a valid location number within the configured range, or reconfigure machine data if additional locations are physically available and need to be enabled.
Changing magazine machine data requires power cycle and may affect existing tool assignments.
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Always verify with your machine manual or a certified technician before performing service procedures.