20091

Verify actual fixed stop mechanical position on the machine. Manually jog axis slowly toward fixed stop using JOG mode (select axis, press JOG soft key on SINUMERIK HMI panel).

Ensure machine is in manual mode and spindle is off before jogging.

Check machine data parameter $MA_FIXED_STOP_POS[axis] via Diagnostics > Machine Data menu. Compare stored position value to actual measured position from Step 1.

If mismatch exists, update $MA_FIXED_STOP_POS[axis] to match actual mechanical stop location. Navigate to Diagnostics > Machine Data > search '20091' or filter by axis.

Changing fixed stop position requires machine parameter write-enable; consult machine builder documentation.

Review NC part program G-code for fixed stop command (typically G60 with coordinate). Verify programmed position equals or exceeds $MA_FIXED_STOP_POS value by at least the amount specified in $MA_FIXED_STOP_CLEARANCE.

Check alarm history and preceding alarms in Diagnostics > Alarm Buffer. Look for axis-specific alarms (e.g., 20070 following error, encoder loss) that may have triggered the movement abort.

Verify axis servo parameters: access Diagnostics > Axis > [select axis] > Servo. Check actual position feedback matches command position and no oscillation is present. Run axis in continuous JOG mode to confirm smooth response.

Check encoder/resolver feedback signal integrity. In Diagnostics > Axis > [axis] > Encoder, confirm encoder value increments smoothly during jog. If encoder value jumps or freezes, service encoder connection or resolver.

Do not operate machine if encoder feedback is unstable; collision risk during fixed stop.

Review $MA_FOLLOW_ERROR_MAX[axis] and $MA_FOLLOW_ERROR_LIMIT parameters. If axis has heavy load or friction at fixed stop position, increase $MA_FOLLOW_ERROR_MAX cautiously and re-test fixed stop cycle.

Check $MA_FIXED_STOP_ALARM_MASK[axis] in Diagnostics > Machine Data. If bit is set (=1), the alarm is masked/suppressed. Verify this is intentional per machine specification; if unintended, clear the bit.

Verify axis readiness before fixed stop command execution. In NC program, ensure all preparatory functions (G-code reset, coordinate system setup) complete before G60/fixed stop command. Add M03/M04 spindle check if required.

Check MD ALARM_REACTION_CHAN_NOREADY in Diagnostics > Machine Data > Channel Settings. Confirm alarm reaction is appropriate (typically 'Continue' or 'Stop'); if set to 'Abort', axis movement may halt prematurely.

If alarm is masked intentionally, document reason in machine log and verify fixed stop position accuracy by alternative means (e.g., manual probe cycle post-traverse).