Function block diagram (FBD)
The function block diagram is a graphically oriented IEC 61131 programming language. It works with a list of networks, where each network contains a structure that can contain logical and arithmetic expressions, calls of function blocks, a jump or a return instruction.
Boxes familiar from boolean algebra are used here. Boxes and variables are connected by connecting lines. The signal flow in the network runs from left to right. The signal flow in the editor runs from top to bottom, starting with network 1.
Example
Note
CFC is also a programming language based on the same principle as FBD, but with the following differences:
- The CFC editor is not network-oriented.
- You can freely place the elements in the CFC editor.
- Direct insertion of feedbacks is possible.
- The order of execution is determined by a list of currently inserted elements, which you can change.
See also