FBD Functions

This information applies to the Compact GuardLogix 5380, CompactLogix 5380, CompactLogix 5480, ControlLogix 5580, and GuardLogix 5580 controllers.
FBD Functions are implemented in accordance with IEC 61131-3 Edition 3. Arithmetic and Numeric functions are provided in the Function Block Diagram language. Ladder Diagram and Structured Text languages include Arithmetic and Numeric as operators and functions.
FBD Functions have one or more inputs and one output. FBD Functions are implemented for efficiency, have smaller footprints and use less system resources to operate than FBD Function Blocks.
FBD Functions
  • Require all inputs and outputs. All inputs must be of a supported data type.
  • Do not have backing tags or predefined data types. Connected input values do not convert to predefined data types.
  • Do not have EnableIn bits and are always executed.
Example: Add Function
ADD_FBD Function
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