61303

Access the NCK measuring parameters via HMI: Diagnostics > Machine Parameters > Measuring > Search for parameter containing '_TSA' or reference MD10340 (measuring tolerance band) in machine data. Document current value.

Increase the _TSA parameter value incrementally (typically 0.05-0.10mm steps) to accommodate normal measurement scatter. For tool measurement, increase MD10340 value proportionally. Recalculate based on machine repeatability (±0.05mm typical for servo systems).

Do not exceed 0.5mm tolerance increase without validating against part tolerance requirements and functional safety constraints.

Re-execute the measuring cycle in DRY RUN mode (G65 or equivalent probing cycle) to verify alarm does not recur with new margin setting.

Document the new _TSA value in machine documentation and verify it is persistent after power cycle by checking via Siemens HMI parameter display.

Review the NC program block that triggered the alarm (reference Block %2 number in alarm message). Examine the G65/G66 measuring cycle call and extract the setpoint coordinates (typically P parameter values or SETNORM variable assignments in SINUMERIK 840D).

Cross-reference setpoint values against the actual fixture drawing or calibration certificate. Measure the physical fixture/probe point location with a separate precision instrument and compare to programmed setpoint.

Ensure measuring instrument is calibrated and has traceability within ±0.02mm for servo systems.

Correct the setpoint coordinate in the NC block. For tool length probing, verify the probe tip offset (MD14060 - tool length offset) is correctly entered in the tool offset table via HMI: Parameters > Tool Offsets.

Perform a single block dry run of the corrected measuring cycle and validate that measured result falls within the _TSA margin of the new setpoint.

Access the NCK diagnostics via Siemens HMI: Diagnostics > Axis > [Channel %1] and observe the actual feedback position (ISPOS) vs. setpoint position (SOLLPOS) during a manual jog to the measuring point. Log values before and after jogging 50mm away then returning.

Ensure axis soft limits are disabled during diagnostic jog movements.

Check for encoder runout by monitoring FEEDBACK signal in cyclic mode while slowly rotating the measuring spindle (G04 P1000 dwell). If feedback value oscillates ±0.05mm or greater, mechanical runout is present; inspect probe retention and spindle bearings.

Verify axis calibration: Home the axis using the reference point (G74 homing cycle), then jog to a known physical location (e.g., fixture edge with external indicator). Compare ISPOS value to actual physical position. If offset exceeds 0.1mm, run re-calibration via HMI: Machine > Axis Calibration or reference MD10320 (reference offset).

Axis recalibration may require SERVICE mode access and machine re-homing sequence.

After calibration correction, re-execute the measuring cycle and confirm alarm 61303 is resolved. If runout was detected, schedule spindle bearing service and probe stylus replacement.