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Check the current CNC mode on the operator panel. Verify if machine is in AUTO, MDI, EDIT, or HANDLE mode.

Access PMC ladder diagnosis screen (PMC > LADDER) and identify which G or F address is being written to for axis commands. Note the ladder rung number and axis address.

Verify the interlock logic in the ladder that should prevent PMC axis commands when CNC is in control. Check for proper use of mode signals (F0000-F0007) and axis control status bits (G0140-G0147).

Modify ladder logic to add or correct interlock conditions using CNC mode signals and axis busy flags before allowing PMC axis movement commands. Ensure proper sequencing between CNC and PMC control handoff.

Do not modify ladder logic without backing up the existing PMC program and documenting all changes.

Review CNC parameters 8010-8019 (PMC axis control enable parameters). Verify which axes are configured for shared CNC/PMC control.

Parameter changes require machine builder documentation. Incorrect settings can disable axes entirely.

Check PMC addresses G0054.0-.7 (axis control request from PMC) and F0054.0-.7 (axis control grant from CNC). Verify the handshake sequence is completing properly in ladder monitor.

Verify that the PMC ladder waits for the axis control grant signal (F address bit ON) before issuing any movement commands through G-addresses.

Add or correct the control request/grant handshake logic in the PMC ladder. Ensure axis commands only execute after successful control transfer and that control is properly returned to CNC after PMC operation completes.

Interview the operator to determine exact actions taken immediately before alarm occurred. Check for mode switch changes, MPG selection, or feedhold button presses.

Review the alarm history and PMC trace data if available to identify the exact timing of operator panel signals and PMC axis command status when alarm triggered.

Verify that PMC ladder includes proper abort/interrupt handling logic that safely terminates PMC axis commands when operator interventions occur (feedhold F0001.7, mode changes F0000-F0003).

Add ladder logic to monitor operator intervention signals and immediately halt PMC axis commands while releasing control back to CNC when manual actions are detected. Include proper deceleration and position confirmation logic.