What is a safety interlock in gate systems and how does it function?

• A. A device that detects obstacle during operation
• B. A device that logs safety events
• C. A device that disables the gate if someone is near
• D. A device that ensures the gate cannot operate unless a defined safety condition is met (e.g., gate closed); wired into the safety circuit

Answer: (D)

A safety interlock is a device that prevents the gate from moving until a defined safety condition is met, typically that the gate is fully closed and the protected area is clear. It is wired into the safety circuit so the drive controller can only receive a start signal when the interlock is in its safe state. If the gate is not closed or the latch is released, the interlock opens the circuit and the safety system stops the gate, often causing an immediate stop or safe reversal.

This is different from obstacle sensors, which detect objects during movement, or logging devices that merely record events. A safety interlock’s purpose is to enforce a safe condition before motion can occur, ensuring the gate cannot operate unless the defined safety condition is met.