In ladder logic, what do rungs, contacts, and coils represent?

In ladder logic, what do rungs, contacts, and coils represent?

• A. Rungs represent logic steps; contacts simulate inputs; coils represent outputs.
• B. Rungs represent outputs; contacts simulate inputs; coils represent inputs.
• C. Rungs represent memory elements; contacts are timers; coils are counters.
• D. Rungs represent data storage; contacts are program flow; coils are registers.

Answer: (A)

Rungs are the individual control steps that connect from supply to load, showing the path that must be completed for an action to occur. Contacts are the input conditions on a rung, acting as switches that model sensors or pushbuttons and determine whether the rung’s logic is true. Coils are the outputs on the rung; when the rung’s conditions are met, the coil is energized to drive an actuator such as a motor, lamp, or relay. So, rungs represent the logical steps, contacts simulate inputs, and coils represent outputs.

Rungs are the individual control steps that connect from supply to load, showing the path that must be completed for an action to occur. Contacts are the input conditions on a rung, acting as switches that model sensors or pushbuttons and determine whether the rung’s logic is true. Coils are the outputs on the rung; when the rung’s conditions are met, the coil is energized to drive an actuator such as a motor, lamp, or relay. So, rungs represent the logical steps, contacts simulate inputs, and coils represent outputs.