28000

Check Physical Safety Doors

Verify all safety doors, guards, and enclosures are properly closed and latched. Check door switch alignment and mechanical operation.

Never bypass safety interlocks - serious injury can occur

Verify Door Switch Status

Navigate to Diagnostics > PLC > I/O Status and check safety door input signals (typically DB21.DBX0.0 to DBX0.7). Signals should show '1' when doors are closed.

Use Service > Diagnosis > Safety to view all safety-related I/O states in one screen

Test Door Switch Operation

Open and close each safety door while monitoring the corresponding input signal to verify proper switch operation and wiring integrity.

Reset Safety System

After confirming all doors are closed, press the safety reset button (if equipped) or cycle the safety enable key switch to reset the safety PLC.

Check All E-Stop Buttons

Visually inspect all emergency stop buttons on the machine, pendant, and control panel. Ensure none are pressed or mechanically stuck.

Only reset E-stops after confirming the emergency condition is cleared

Verify E-Stop Circuit Continuity

Check Diagnostics > PLC > I/O Status for emergency stop input (typically DB21.DBX1.0). Signal should be '1' when E-stop circuit is complete.

E-stop circuits are series-wired - a single open contact will trigger the interlock

Test E-Stop Reset Function

After confirming all E-stops are released, activate the safety reset sequence per machine procedure. Monitor the safety enable output signal (DB21.DBX10.0) for proper reset.

Check Safety Relay Operation

If inputs show correct but interlock persists, check safety relay coil voltage and contact operation using multimeter on safety relay terminals.

Identify External Safety Devices

Review machine documentation to identify all external safety devices (light curtains, laser scanners, pressure mats) connected to the safety system.

Check the safety circuit diagram in the electrical documentation for complete device list

Check Device Status Indicators

Examine LED status indicators on each safety device. Red or flashing lights typically indicate fault conditions or beam interruption.

Do not attempt to bypass or disable safety devices

Clear Safety Device Obstructions

Remove any objects blocking light curtains or pressure mats. Clean optical surfaces with appropriate cleaning materials per manufacturer specifications.

Verify Device Communication

Check safety device communication status in Diagnostics > Safety > External Devices. Verify proper voltage supply and signal integrity to each device.

Check Safety PLC Status

Navigate to Diagnostics > Safety > PLC Status and verify safety PLC is in RUN mode with no fault indicators. Check CPU status LEDs on safety PLC module.

Safety PLC fault codes are often displayed on the safety module's diagnostic display

Verify Communication Parameters

Check machine data MD36231 (SAFETY_COMM_ADDRESS) and MD36232 (SAFETY_COMM_TIMEOUT) for correct values matching safety PLC configuration.

Test Communication Link

Use Service > Safety > Communication Test to verify data exchange between CNC and safety PLC. Check for consistent handshake signal timing.

Reset Safety Communication

Power cycle the safety PLC module or execute safety system restart from Service > Safety > System Reset menu to re-establish communication.

Check Drive Ready Status

Navigate to Diagnostics > Drive > Overview and verify all axis drives show 'Ready' status with no fault codes displayed.

High voltage present in drive cabinets - use proper PPE and lockout procedures

Verify Drive Enable Signals

Check drive enable output signals in Diagnostics > PLC > Outputs. Drive enable outputs (typically DB31.DBX0.0-0.7) should be active when safety is satisfied.

Test Drive Enable Circuit

Measure 24VDC at drive enable terminals with safety system active. Check for proper voltage and current flow through enable circuit wiring.

Reset Drive System

Execute drive reset sequence from Service > Drive > Reset All Drives after confirming enable circuit integrity and safety system status.