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Identify affected axis %1 and gear stage from alarm parameter 2 (1=SG1, 2=SG2, etc.). Note the current gear ratio from parameter 3.

Navigate to NCK -> Configuration -> Machine Data -> Axis-Specific MD -> Safety Integrated. Check MD $MA_SAFE_VELO_LIMIT[n] where n corresponds to the gear stage indicated in parameter 2.

Check encoder resolution in MD $MA_ENC_RESOL and gear ratio settings in MD $MA_GEAR_STEP_MAX_VELO and MD $MA_GEAR_STEP_CHANGE_POSITION for the affected gear stage.

Calculate maximum permissible velocity: Max_Velo = (500000 Hz) / (Encoder_Lines * Gear_Ratio_Factor). Reduce MD $MA_SAFE_VELO_LIMIT[n] to below this calculated value.

Reducing safe velocity limits affects Safety Integrated functionality. Coordinate changes with safety validation personnel and update safety acceptance documentation.

After modification, perform NCK reset (PLC -> NCK -> Reset) and re-validate Safety Integrated functions according to acceptance test procedure.

Navigate to NCK -> Configuration -> Machine Data -> Axis-Specific MD -> Gear Stage. Review MD $MA_GEAR_STEP_MAX_VELO[n] and MD $MA_GEAR_STEP_MIN_VELO[n] for gear stage indicated in alarm parameter 2.

Verify mechanical gear ratio against machine documentation. Check MD $MA_GEAR_STEP_NUMERATOR[n] and MD $MA_GEAR_STEP_DENOMINATOR[n] match actual mechanical setup.

Recalculate required monitoring frequency: Freq = (Safe_Velo * Encoder_Lines * Gear_Numerator) / Gear_Denominator. Ensure result is below 500 kHz.

If gear ratio is correct but frequency exceeds limit, either reduce MD $MA_SAFE_VELO_LIMIT[n] for this gear stage or consider using encoder with lower resolution if mechanically feasible.

Changing encoder resolution requires hardware modification and complete re-commissioning of axis and Safety Integrated functions.

Check current encoder configuration in NCK -> Configuration -> Machine Data -> Axis-Specific MD -> Encoder. Review MD $MA_ENC_RESOL (encoder lines per revolution) for measuring system 1.

Calculate critical velocity limit: Max_Safe_Velo = 500000 / (MD $MA_ENC_RESOL * Gear_Ratio). Compare with current MD $MA_SAFE_VELO_LIMIT[n] value.

If high resolution encoder is required for positioning accuracy, reduce MD $MA_SAFE_VELO_LIMIT values for affected gear stages to remain within hardware monitoring limits.

Alternative: Check if encoder supports interpolation settings in MD $MA_ENC_IS_INDEPENDENT and MD $MA_ENC_INVERS that might reduce effective monitoring frequency without changing physical encoder.

Document final safe velocity limits in safety parameter protocol and perform complete Safety Integrated acceptance test per SINUMERIK Safety Integrated commissioning guidelines.

All Safety Integrated parameter changes must be validated and documented according to EN ISO 13849 and machine-specific safety requirements.

Navigate to Commissioning -> Safety Integrated -> Extended -> Check Consistency. Run automatic consistency check for all safety-relevant machine data.

Check NCK alarm history for preceding alarms related to battery voltage (1000 series), data backup (4000 series), or safety parameter errors (26xxx, 27xxx series) that might indicate data corruption.

Compare current MD values with archived commissioning data or backup files. Review MD $MA_SAFE_VELO_LIMIT, MD $MA_ENC_RESOL, and all gear stage MDs against known-good configuration.

If corruption suspected, restore safety machine data from validated backup file via Commissioning -> System Data -> Load. Use only safety-validated backup files with complete acceptance test documentation.

Restoring machine data requires complete re-acceptance of Safety Integrated functions. Machine must not operate in safety-relevant mode until validation complete.

After restoration, perform NCK power cycle (complete control power off/on), then execute full Safety Integrated acceptance test procedure and update all safety documentation.