The Procedural Function Chart (PFC) defines specific tasks. PFCs are made up of steps, transitions and actions, and are most often used to perform sequential control. You define the task you want to perform by graphically representing the steps, transitions, and actions involved. A sequence in an PFC is drawn as a series of steps, which are represented by boxes, and vertical lines that contain the transition from one step to the next. Each step can contain a set of actions that affect the process. Once defined, the PFC can be executed.