Networks

Programming units in FBD are subdivided into networks which are consecutively numbered in ascending order and which can contain graphically illustrated elements such as operands, FB calls, assignments, jumps, or labels. The networks are processed in ascending order.

In a network, the program code has to be in a tree structure, which means no parallel interconnection, no splitting, and no explicit feedback loops.

The logical elements of a network are joined by lines to make a tree-like formation (short form: tree) with the root to the right; in which the boxes in this tree act as nodes. Exception: Multiple assignments as well as jump and return statements fan this tree out in opposite directions. The elements are connected automatically by the editor according to their insertion position. Free placement is not possible.