330-0003

Visual E-Stop Inspection

Check all emergency stop buttons on machine panel, operator pendant, and remote stations for engaged (twisted/pulled) position.

Never bypass emergency stops - they are critical safety devices

Reset E-Stop Buttons

Twist clockwise or push to release all emergency stop buttons. Ensure buttons return to normal (raised) position with audible click.

Some older machines require specific sequence - main panel first, then pendant

Verify PLC Input Status

Access PLC menu via MOD function, select 'PLC Status' and check X121.1 or configured E-stop input shows '1' (active high) after reset.

Input assignment may vary - check machine parameter MP7300.x for actual E-stop input mapping

Clear Alarm and Test

Press CE key to clear alarm, then test E-stop function by activating and releasing to ensure proper operation.

Check All Safety Guards

Inspect all machine doors, access panels, and safety guards for proper closure. Look for loose latches or misaligned strike plates.

Check for chips or debris preventing complete door closure

Verify Light Curtain Status

If equipped, check light curtain indicators for beam interruption. Clear any obstructions and verify green 'OK' status light.

Never block or bypass light curtains - they prevent serious injury

Test Interlock Switches

Manually operate each safety switch while monitoring PLC inputs in MOD > PLC Status menu. Each switch should show state change.

Magnetic switches may fail due to coolant contamination - clean switch and magnet surfaces

Check Safety Relay Module

Locate safety relay module (typically Pilz PNOZ or similar) and verify status LEDs show normal operation per manufacturer documentation.

Access PLC Diagnostics

Enter MOD function, select 'PLC' then 'Program Status' to view active PLC program execution and any internal fault flags.

Look for flashing or red status indicators in the PLC status display

Check Safety Logic Markers

Monitor internal markers M100-M120 range (typical safety logic area) for stuck or false conditions that prevent control-ready activation.

Only qualified personnel should modify PLC logic

Verify Control-Ready Output

Check PLC output Q124.0 (or configured control-ready output) status in PLC output display - should be '1' when all safety conditions met.

Cross-reference with machine electrical drawings for actual output assignment

Review PLC Error Log

Access PLC error log via MOD > PLC > Error Log to identify any recent PLC faults or watchdog timeouts that could affect safety logic.

Measure 24VDC Supply Voltage

Use multimeter to verify 24VDC supply at safety relay module and PLC input terminals reads 24V ±10% (21.6-26.4VDC).

Use proper lockout/tagout procedures when working in electrical panels

Check Supply Loading

Measure current draw on 24VDC supply and compare to supply rating. Overloaded supplies cause voltage drop affecting safety circuits.

Typical safety circuit draws 2-5A - check supply nameplate rating

Inspect Wiring Connections

Check all 24VDC connections at terminal strips, relay sockets, and PLC terminals for looseness, corrosion, or burning.

Use thermal imaging if available - hot connections indicate resistance problems

Test Supply Ripple

Use oscilloscope to check 24VDC supply for excessive ripple or noise that could cause safety relays to drop out intermittently.

Identify Safety Relay Module

Locate main safety relay (typically labeled K1 or similar) in electrical cabinet and note model number and wiring configuration.

Safety relays often have test buttons - use per manufacturer instructions

Test Relay Coil Continuity

With power off and relay removed, use multimeter to test coil resistance (typically 200-2000 ohms depending on voltage rating).

Ensure power is locked out before removing relays

Check Contact Operation

Manually activate relay coil with appropriate DC voltage and verify all safety contacts operate correctly using continuity tester.

Safety relays have multiple contact sets - all must operate simultaneously for proper function

Replace and Test

Install replacement safety relay with identical part number and test complete E-stop cycle to verify proper operation before returning to service.