330-00CA

Visual Inspection of Guard Doors

Check all guard doors and safety gates associated with the affected axis group. Verify proper closure and latching mechanism engagement.

Never bypass safety interlocks - ensure all personnel are clear before closing doors

Check Safety Status in TNC

Navigate to MOD function and select 'Safety' to view current safety door status. Check which specific axis group door is reported as open.

Use the safety status display to identify exactly which door sensor is active

Verify Door Alignment

Ensure guard door is properly aligned with safety switch actuators and that door seals or gaskets are not preventing complete closure.

Check for debris or swarf buildup around door frames that could prevent proper closure

Test Safety Switch Operation

With doors closed, check safety switch LED indicators. Most safety switches have diagnostic LEDs showing actuator presence and switch status.

Pilz PSEN or Schmersal safety switches typically have dual LED indicators for diagnostics

Measure Switch Continuity

Using a multimeter, verify continuity across safety switch contacts with door closed. Check both NO and NC contacts according to switch wiring diagram.

Power down safety circuits before electrical testing to prevent damage to safety PLC inputs

Check Actuator Positioning

Verify magnetic actuator or cam is properly positioned and secured to door. Check actuator alignment with sensor head and proper operating distance.

Most magnetic safety switches require actuator within 5-8mm and proper alignment orientation

Check SPLC Communication Status

In TNC diagnostics, navigate to PLC menu and check safety PLC communication status. Verify SPLC interface is active and responding.

Look for communication timeout errors or cyclic data exchange failures in the PLC status display

Verify Safety PLC Program State

Check that safety PLC is in RUN mode and axis group safety functions are enabled. Review safety PLC diagnostic outputs for fault conditions.

Only qualified safety engineers should modify safety PLC programs or parameters

Reset Safety System

Perform controlled safety system reset through TNC MOD function. Select 'Safety Reset' and follow the guided reset procedure for the affected axis group.

Safety reset may require specific key sequence or acknowledgment depending on safety category level

Inspect Safety Circuit Wiring

Visually inspect all wiring from guard door switches to safety PLC inputs. Look for damaged cables, loose connections, or signs of wear at cable entry points.

Use lockout/tagout procedures when accessing electrical panels for wiring inspection

Test Cable Continuity

Disconnect safety switch cables at both ends and test continuity of each conductor. Check for proper wire identification and verify against wiring diagrams.

Safety circuits often use twisted pair cables - test both conductors and shield continuity separately

Verify Safety PLC Input Status

Check safety PLC input module status LEDs and diagnostic information. Compare actual input states with expected values from closed door switches.

Use safety PLC programming software to monitor real-time input values and compare with physical switch positions