Which term describes a wiring or programming technique used for sequencing and safety by ensuring outputs turn on or off under specified conditions?

• A. Interlox
• B. Seal-in circuit
• C. Latch
• D. Transducer

Answer: (A)

Interlocking is about ensuring safe, proper sequencing by making an output energize only when all required conditions are met. In practice, this means wiring or programming the control so energy can flow to a device only if every safety and condition input is true. For example, a machine might require a closed guard and a pressed start button before it can run; if the guard opens, the energy path is broken and the output turns off. This approach prevents unsafe states and enforces the correct order of operations.

This differs from a holding or seal-in circuit, which is used to keep an output energized after an initial actuation, until an explicit off condition breaks the hold. It also differs from a latch, which is a general memory element that preserves a state, and from a transducer, which converts one signal type to another.