The SFC program consists of alternating states and transitions, and its essence is state transitions. You can transfer a state to the next state through conditions, transfer conditions to the next state when multiple states are active simultaneously, or activate multiple states simultaneously through conditional transfer.

• SFC does not divide the network, the program is a whole. Divide the program into grids, and each grid can only accommodate one component.

• SFC does not have a fixed maximum number of components. In principle, the width should not be too large.

• There must be an initial step. For scenarios involving multiple initial steps, please derive below this initial step.

• It is illegal to jump from one state to another without passing a transition condition. In this situation, please use a normally open contact (such as LD Always_On) to pass through within the transfer conditions.

• It is illegal to have one transfer condition adjacent to another transfer condition. In this situation, please combine the logic within the transfer conditions.

• A single horizontal line must connect multiple transitions to indicate the selection logic for these transitions.

• The double horizontal line must connect multiple states to indicate the synchronization logic for these states.