22055

In NCK menu, navigate to Spindle > Position and verify the spindle axis shows a valid reference status (indicated by REF lamp or position value not showing dashes). If reference status is invalid, perform manual home run using G74 with appropriate spindle index pulse configuration (MD10920 'Reference point fine positioning').

Ensure spindle is at safe speed (typically 0 RPM) before attempting reference run

Check MD20050 (Spindle assignment) confirms correct spindle number assignment to the channel. Verify MD10910 and MD10911 are set correctly for your spindle type (absolute or incremental encoder). For encoders without reference cam, MD10911 should be set to 'Absolute encoder' to skip G74 requirement.

If spindle uses absolute position feedback, verify encoder calibration in PLC > Spindle > Encoder menu. Check that the encoder zero position corresponds to actual mechanical spindle position (typically tool change position or 0° orientation). Recalibrate if necessary using MD10942 'Reference point fine positioning speed'.

Verify the Master Spindle number in MD20060 matches the spindle being used for synchronization. Check that the Master Spindle itself has completed referencing (G74 command or automatic startup reference). Navigate to NCK > Spindle > Synchronization menu to confirm MS is showing valid position reference.

Master Spindle must always be referenced before any slave spindle can execute positioned moves

In Spindle Parameters (MD22260), verify 'Spindle positioning enable' is set to '1' (active). Check MD22250 'Positioning speed factor' is set appropriately (typically 0.5 to 1.0). Verify MD22255 'Positioning acceleration' and MD22256 'Positioning deceleration' are within acceptable ranges for your application.

Confirm the block syntax references MS correctly: command should use 'SPOS=MS' or similar synchronization syntax depending on SINUMERIK version. Check NC program for any conditional logic that might skip Master Spindle initialization. Run diagnostic report via Diagnostics > Spindle > Position Memory to view current position state of all spindles.

Review the NC block command: check the SPOS (spindle positioning command) value and verify it is within ±360° or the appropriate range for your spindle type. Check that the block does not contain conflicting speed parameters (e.g., F-word and spindle speed command simultaneously). Use List > Current Block in NCK menu to view exact parsed values.

If SPOS value is extremely large (e.g., multiple full rotations), verify this is intentional

Examine MD22250 'Positioning speed factor' and compare against spindle maximum RPM. If positioning speed factor is set too high relative to spindle capability, reduce it in 0.1 increments. Check encoder resolution (MD10981 'Encoder pulses per revolution') - lower resolution may require lower positioning speed factors to maintain sync accuracy.