10601

Access Machine Data Parameters

Navigate to Commissioning > Machine Data > Axis-specific data for X-axis and check MD36100 $MA_POS_LIMIT_PLUS[AX1] value.

Compare the MD36100 value with your machine's actual physical travel range - it should be at least 2-5mm less than the hardware limit position.

Verify Software Limit Activation

Check MD36120 $MA_SOFT_LIMIT_PLUS_ENABLE[AX1] is set to TRUE to enable software limit monitoring.

Never disable software limits without implementing alternative protection methods.

Test and Adjust Limits

After backing off the limit switch, perform a controlled jog to determine actual travel range and set MD36100 to appropriate value with safety margin.

Use the machine coordinate system display to accurately measure your working envelope.

Check Reference Point Status

In Diagnostics > Service > Axis states, verify that the X-axis shows 'Referenced' status and check for any reference point alarms in the alarm buffer.

Never assume position accuracy without confirmed reference point status.

Perform Reference Point Return

Execute reference point return sequence using JOG mode > REF button or G74 command to re-establish accurate position reference.

Monitor MD34200 $MA_REFP_SET_POS[AX1] to ensure reference point position matches your machine setup.

Verify Encoder Signals

Check encoder feedback in Diagnostics > Drive > Encoder signals to ensure clean reference marks and proper signal quality.

Look for consistent reference pulse detection and verify MD31020 $MA_ENC_REFP_MODE[AX1] matches your encoder type.

Inspect Mechanical Components

Visually inspect X-axis ways, ball screws, and linear guides for chips, debris, or obvious wear that could cause binding.

Ensure machine is powered down and locked out before mechanical inspection.

Check Following Error History

Review following error values in Diagnostics > Axis > Following error and check if MD36410 $MA_MAX_AX_VELO limits are appropriate for current mechanical condition.

Excessive following errors often precede overtravel conditions - monitor MD36200 $MA_POSCTRL_GAIN for optimal tuning.

Manual Axis Movement Test

With drives disabled, manually move the X-axis through its range to identify binding points or excessive resistance.

Compare manual movement resistance across the entire travel range - it should be consistent.

Review Active Work Offsets

Check current work offset values in Parameters > Work offsets and verify G54-G59 values are within machine coordinate system limits.

Use machine coordinate display (MPOS) rather than work coordinates (WPOS) when troubleshooting overtravel issues.

Analyze Program Path

Review the NC program that was running when alarm occurred, paying attention to G-code moves, coordinate system calls, and any G52/G92 local coordinate shifts.

G92 coordinate system shifts are cumulative and can cause unexpected position offsets.

Verify Tool and Fixture Compensation

Check tool length compensation values and any active fixture offsets that may extend the effective tool path beyond expected limits.

Consider the combined effect of work offset + tool compensation + any active G52 shifts when calculating actual machine positions.

Test Limit Switch Function

In Diagnostics > PLC > Inputs, monitor the limit switch input signal while manually actuating the switch to verify proper electrical function.

Check both normally-closed and normally-open switch logic according to your PLC input configuration.

Verify Switch Position

Measure the actual position where the limit switch activates and compare with machine specifications and MD36100 software limit settings.

Adjusting limit switch positions affects machine safety - document all changes and verify proper operation.

Check PLC Logic

Review PLC program logic for limit switch processing and verify DB31 DBX60.0 (positive limit X-axis) signal path is correct.

Use PLC program status to trace signal flow from physical input through any safety logic to the NC kernel.