Hierarchy of SFC Programs

Each SFC program can have one or more child programs.

  • Child programs are written in SFC.
  • They are started or stopped in the actions of the parent program.
  • The number of hierarchy levels must not exceed 19.
  • A child program can also have children.
    • When a child program is stopped, its children are also stopped.
    • When a child program is started, it must start its children.
    • A child program is controlled (started or stopped) from the action blocks of its parent program.
    • Designing a child program is:
      • a simple way to program an action block in SFC language.
      • very useful for designing a complex process and separate operations due to different aspects of the process.
        • Example: It is common to manage the execution modes in a parent program and to handle details of the process operations in child programs.