Division In Logic

[Anonymous user]

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When doing division in logic, the selection of integer or floating-point division depends on the input types. If both the numerator and denominator are integers (DINT, INT, SINT) it will do integer division. If one is not, it will do floating-point division.

The following examples show the differences:

 Out := (8/15);     (* will return 0 *) Out := (8.0/15);   (* will return 0.5333333 *) Out := (8/15.0);   (* will return 0.5333333 *) Out := (8.0/15.0); (* will return 0.5333333 *)

If using variables, DINT_TO_LREAL type conversions can be used to force floating-point division. E.g.

 PROGRAM DivideTest VAR  In1 AT %I(.In1.CurrentValue) : DINT;  In2 AT %I(.In2.CurrentValue) : DINT;  Out AT %M(.Out.CurrentValue) : LREAL; END_VAR  Out := DINT_TO_LREAL(In1) / DINT_TO_LREAL(In2); END_PROGRAM

This also affects FBDs and other IEC 6-1131 logic types.


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