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Siemens SINUMERIK Controller
PLC · Intermediate · 30-120 minutes
Siemens 840D 107088 - MCU: Not allowed in this PLC mode!
Siemens SINUMERIK alarm 107088: MCU: Not allowed in this PLC mode!. This alarm indicates an error condition in the NC program or control configuration that must be resolved before the operation can continue.
107088
Siemens 840D 107088 - MCU: Not allowed in this PLC mode!
MCU: Not allowed in this PLC mode!
Siemens SINUMERIK alarm 107088: MCU: Not allowed in this PLC mode!. This alarm indicates an error condition in the NC program or control configuration that must be resolved before the operation can continue.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Common Causes
- Part program contains an illegal or unsupported command for the current machine configuration
- Parameter or machine data setting incompatible with the commanded operation
- Required option or function not enabled on this SINUMERIK control
- Incorrect axis assignment or configuration for the commanded function
- Software version or compile cycle version mismatch
Troubleshooting Steps
- 1Note the full alarm message including any parameter values shown (e.g., axis number, block number, channel).
- 2Identify the program block or operation that triggered the alarm.
- 3Review the SINUMERIK alarm manual for alarm 107088 to identify the specific cause and remedy.
- 4Check the relevant machine data parameters referenced in the alarm.
- 5If the alarm persists after correcting the program, contact Siemens technical support with the full alarm text and machine data backup.
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