From an external point of view, a Function Block Diagrams consists of inputs and outputs, with data being processed between them. From an internal point of view, a Function Block Diagrams consists of POUs and their connections which represent data (signals) and act as assignment operators in ST. The overall behavior is composed of the behavior of the inserted POUs which call other POUs or library POUs.

Code in the “Continuous Function Chart (CFC)” implementation language mainly illustrates the data flow through the system. Therefore, a continuous function chart is also referred to as a "signal flow chart".

In the page-oriented CFC editor, you can wire POUs to each other and create well-structured Function Block Diagrams distributed over multiple pages. The page-oriented editor behaves like the CFC editor, but provides the following functionality:

The page-oriented editor behaves like the CFC editor, but provides additional functionality.