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Siemens SINUMERIK Controller
Spindle · Intermediate · 30-120 minutes
Siemens 840D 21650 - Channel axis overlaid motion not allowed
Alarm 21650 is triggered when an overlaid motion (FLIN, FPIN, or M-function overlay) is commanded on an axis where machine data MD20110 FRAME_OR_CORRPOS_NOTALLOWED is set to inhibit such operations. This safety restriction prevents conflicting kinematic transformations or correction positions from being applied simultaneously with overlay motions.
21650
Siemens 840D 21650 - Channel axis overlaid motion not allowed
Channel axis overlaid motion not allowed
Siemens SINUMERIK 840D alarm 21650: Channel axis overlaid motion not allowed. This alarm indicates a program or channel-level error on the SINUMERIK control. The part program or machine function cannot be executed as commanded.
Root Cause Summary
Alarm 21650 is triggered when an overlaid motion (FLIN, FPIN, or M-function overlay) is commanded on an axis where machine data MD20110 FRAME_OR_CORRPOS_NOTALLOWED is set to inhibit such operations. This safety restriction prevents conflicting kinematic transformations or correction positions from being applied simultaneously with overlay motions.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Access Siemens SINUMERIK 840D HMI or engineering software; navigate to Machine Data (MD) settings via Diagnostics > Machine Data or through SINUMERIK Operate interface.
- 2
Locate MD20110 FRAME_OR_CORRPOS_NOTALLOWED for the affected channel. Verify the current setting: a value of 1 (TRUE) inhibits overlaid motions; 0 (FALSE) allows them. Document the current configuration.
- 3
Review the NC program: confirm whether FLIN, FPIN, or M-function overlay is actually required. If overlay is not essential, remove the overlay command from the program and re-execute.
Changing MD20110 may compromise machine safety; consult machine builder documentation before modification.
- 4
If overlay motion is mandatory, contact the machine builder or OEM to confirm MD20110 can be safely disabled (set to 0). If approved, modify MD20110, store the changes, and perform a warm restart (warmstart) of the NCK via Diagnostics > NCK Functions.
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