Which statement best describes Sequential Function Chart (SFC) in PLC programming?

Which statement best describes Sequential Function Chart (SFC) in PLC programming?

• A. Sequential Function Chart uses a flowchart-like language that uses steps and transitions to control a process or application.
• B. Structured Text is a graphical language that uses blocks to connect logic.
• C. Function Block Diagram is a ladder-like arrangement of blocks.
• D. Ladder Logic resembles a ladder with rungs and contacts.

Answer: (A)

Sequential Function Chart models a process as a sequence of steps (states) with transitions that move the control from one step to the next when specific conditions are met. This flowchart-like structure, built from steps and transitions, is exactly how SFC organizes the control flow to execute a process in stages. In practice, each step can perform actions, and transitions determine when the process advances to the next step, making it ideal for representing ordered sequences and machine states. Other PLC programming approaches describe different styles: Structured Text is a textual programming language, not a graphical flow of steps and transitions. Function Block Diagram uses interconnected blocks to show signal flow, not a step-and-transition sequence. Ladder Logic resembles a ladder with rungs and contacts, focusing on relay-like logic rather than sequential states.

Sequential Function Chart models a process as a sequence of steps (states) with transitions that move the control from one step to the next when specific conditions are met. This flowchart-like structure, built from steps and transitions, is exactly how SFC organizes the control flow to execute a process in stages. In practice, each step can perform actions, and transitions determine when the process advances to the next step, making it ideal for representing ordered sequences and machine states.

Other PLC programming approaches describe different styles: Structured Text is a textual programming language, not a graphical flow of steps and transitions. Function Block Diagram uses interconnected blocks to show signal flow, not a step-and-transition sequence. Ladder Logic resembles a ladder with rungs and contacts, focusing on relay-like logic rather than sequential states.