Function block diagram

The Function Block Diagram ( FBD abbreviation ) is a five languages ​​in EN 61131-3 (IEC 61131-3) defined for the programming of programmable logic controllers (PLC). It is often also function block diagram ( FBD abbreviation ) called ( including Siemens Step7 ). The graphically oriented programming language used in their representation of the logic symbols of Boolean algebra. It is especially suitable for logic control and especially with beginners and advanced programmers little popular since the program logic is relatively easy to understand by the visualization.

Your CAD functionalities allow easy positioning and connecting functions and function blocks and their variables.

This also includes the FBD ( Function Block Diagram / ​​free -translated: "Functional Block Diagram "). While the FBS " only the words and their meaning " including, the FBD is for " picturing " and "function " in charge. The FBD is used for writing programs on the PLC.

An FBD program consists of the following graphic elements:

  • Connections and lines
  • Variables and Constants
  • Functions and function blocks

The signal flow of a FBD program runs from left to right. The processing sequence of the blocks can be set individually.

Example: 100 limit to VALUE1 add, result to / -10000 and write in VALUE2:

  • Programmable logic controller
International Electrotechnical Commission
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