Safety Circuit Fault — Guard Door Open

Machine guard door interlock is open. Motion inhibited in the affected zone until door is closed and circuit resets.

Probable Causes (ranked)

• Guard door physically open — maintenance access or not fully latched
• Interlock switch actuator misaligned after door adjustment or replacement
• Interlock switch failed — no output when door is fully closed
• Wiring to interlock switch damaged — cut by door hinge movement
• Safety controller not detecting interlock input — module issue

Fix Steps

1. 1 Close guard door fully — verify latch engagement, push until it clicks
2. 2 Check interlock switch actuator alignment — tongue must fully insert into switch body
3. 3 Test interlock switch with multimeter for continuity when door is closed
4. 4 Inspect wiring from switch to safety controller — look for wear near hinges
5. 5 Reset safety controller and acknowledge fault at HMI

Suggested Replacement Parts

Parts matched to fault category: Safety Relay

Prices are estimates. Verify part numbers match your equipment before ordering.

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