In ladder diagrams, which element is represented by NO/NC contact symbols and corresponds to physical hardware wired to PLC terminals?

In ladder diagrams, which element is represented by NO/NC contact symbols and corresponds to physical hardware wired to PLC terminals?

• A. Outputs
• B. Inputs
• C. Contacts
• D. Rails

Answer: (C)

In ladder diagrams, NO and NC symbols depict a switch element—the contact. These contacts represent the actual switching part of a device that is wired to PLC terminals, such as the contact portion of a pushbutton, a relay, or a sensor’s internal switch. They dienen to show whether a path is open or closed, reflecting the physical hardware state in the control circuit. That’s why the correct element is Contacts. Inputs refer to the sensing devices themselves, outputs to the actuators or coils, and rails are just the power lines feeding the ladder.

In ladder diagrams, NO and NC symbols depict a switch element—the contact. These contacts represent the actual switching part of a device that is wired to PLC terminals, such as the contact portion of a pushbutton, a relay, or a sensor’s internal switch. They dienen to show whether a path is open or closed, reflecting the physical hardware state in the control circuit. That’s why the correct element is Contacts. Inputs refer to the sensing devices themselves, outputs to the actuators or coils, and rails are just the power lines feeding the ladder.