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Siemens SINUMERIK Controller
Program/G-code · Intermediate · 30-120 minutes
Siemens 840D 101626 - Unknown unit.
Alarm 101626 occurs when the NC program contains a measurement unit specification that the control system does not recognize or support. This typically happens when programming feed rates, dimensions, or coordinates with incorrect or unsupported unit identifiers in the G-code.
Siemens 840D 101626 - Unknown unit.
Unknown unit.
Siemens SINUMERIK operator message 101626: Unknown unit. 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 101626 occurs when the NC program contains a measurement unit specification that the control system does not recognize or support. This typically happens when programming feed rates, dimensions, or coordinates with incorrect or unsupported unit identifiers in the G-code.
Safety
Causes and Fixes
Identify the exact block number where the alarm occurred and examine the NC program line for any unit specifications (check for unusual F, S, or dimension value suffixes).
Verify that only standard unit codes are used: G70 (inch) or G71 (metric), and ensure feed rates use standard formats without custom unit suffixes.
Check machine data MD10240 (SCALING_SYSTEM_IS_METRIC) to confirm the expected base unit system and ensure program units match.
Correct the program by removing invalid unit identifiers or converting to standard SINUMERIK unit formats, then reset the alarm and restart the program.
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