The Function Block programming language is a graphical flow diagram language where program instructions appear as blocks (function blocks). Each function block has inputs and outputs that can be wired to other function blocks to create a visual representation of data flow. In the same way that Ladder Logic is based on relay logic engineering drawings, FBDs are also derived from engineering discipline standards. Before being used as a programming language, FBDs were used in system/software engineering to describe the interrelationships between electronic systems.
The following FBD is from NASA's Space Shuttle program and describes the electronic system relationships in an IBM AP-101S general-purpose computer:
Within Logix, it is important to note that editing FBDs is not supported by all editions of the Logix programming software. Only the Professional, Full, and Lite editions allow you to write programs...
