Extensions of the IEC 61131-3 standard

The enumeration components can also be used as constant variables with the identifier ‎<enumeration name>.<component name>‎. Enumeration components are recognized globally in the project and access to them is unique. Therefore, a component name can be used in different enumerations.

PROGRAM PLC_PRG
VAR
    cbFlower : COLOR_BASIC;
    colorCar : COLOR;
END_VAR

(* unambiguous identifiers although the component names are identical *)
cbFlower := COLOR_BASIC.blue;
colorCar := COLOR.blue;

(* invalid code *)
cbFlower := blue;
colorCar := blue;

For more information, see: ⮫ “Operator: Enumeration Namespace ”.