Which statement best describes Ladder Logic in PLC programming?

• A. It is a CPU type language
• B. It is used to represent control logic as ladder diagrams
• C. It is a memory type
• D. It is an I/O interface

Answer: (B)

Ladder Logic is a graphical PLC programming approach that expresses control logic as ladder diagrams, mirroring traditional relay circuits. Each rung represents a rule: inputs are shown as contacts (normally open or normally closed) and the action is an output coil. When the conditions on a rung are met, the coil is energized and drives the associated device. This visual layout lets you see how signals flow from left to right and how multiple conditions combine in series (AND) or in parallel (OR). PLCs run in a cyclic scan: read inputs, evaluate every rung, and update outputs, which makes debugging intuitive for control systems. It’s not a CPU type language, not a memory type, and not an I/O interface—the choice that best describes Ladder Logic is that it represents control logic as ladder diagrams.