Function Overloading

Function Overloading

This information applies to the Compact GuardLogix 5380, CompactLogix 5380, CompactLogix 5480, ControlLogix 5580, and GuardLogix 5580 controllers.
Function overloading defines two or more functions with the same name but different signature, such as argument or return type. FBD Functions that support overloading take a range of input data types. The output data types depend on the input data types.
FBD Functions follow these rules:
  • Input type promotion
    • Input type promotion
      • Data types rankings from highest to lowest priority:
        LREAL, REAL, ULINT, LINT, UDINT, DINT, UINT, INT, USINT, SINT
      • All inputs promote to the data type of the input with the highest rank before execution
      • If all inputs have a rnak value of DINT or lower, all inputs promote to DINT type before execution
    • Output type depends on the input type
      The function's output type is the promoted input type
For example, Add function,
  • SINT + UINT inputs promote to DINT + DINT inputs. Outputs are DINT
  • USINT + LINT inputs promote to LInt + LINT inputs. Outputs are LINT
  • UNIT + LREAL inputs promote to LREAL + LREAL inputs. Outputs are LREAL
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