10205

Perform a complete power cycle (cold restart) of the control - power off for at least 30 seconds, then power back on to reinitialize all NCK memory structures.

Check the alarm chronology and PLC diagnostics to identify what operation was active when the alarm occurred (mode change, program start, specific G-code execution).

If alarm recurs, perform NCK reset via HMI: Services > NCK > Reset NCK, then reload the part program and machine data.

WARNING: NCK reset will clear all offset values and tool data - ensure you have a backup before proceeding.

Contact Siemens hotline with exact alarm parameters (%1 channel number, %2 module name) and NCK software version for specific internal error code analysis.

Check current NCK software version via HMI: Commissioning > System Data > Software Version. Document the exact version number.

Review Siemens service documentation and Technical Bulletins for known issues with your specific software version related to alarm 10205.

Plan and execute an NCK software upgrade to at least version 4.x or higher, following Siemens upgrade procedures.

WARNING: Software upgrades require complete system backup, proper licensing, and may require machine data adjustments.

After upgrade, perform complete system validation including reference point approach, test programs, and axis movement verification.

Run NCU hardware diagnostics via HMI: Diagnostics > Hardware > NCU Test to check RAM, flash memory, and system bus integrity.

Check NCU battery voltage (should be >3.0V DC). Replace CMOS battery if voltage is low, then reinitialize machine data from backup.

WARNING: Removing battery with power off will cause loss of all machine data and parameters.

If hardware test shows errors, backup all data to CF card or network location, then replace the defective NCU module.

WARNING: NCU replacement requires complete system reinitialization and recommissioning.

After NCU replacement, restore all machine data, tool offsets, and perform full axis calibration and reference point setting.