Documentation

A reference is a variable which only contains a link to a variable or to a function block instance. The used variable may be of elementary or derived data type.

A reference is declared using the keyword REFERENCE TO. Then, the name of the referrede data type follows.
The pointer is initialised using the REF= operator.

Example:

VAR
  MyRef: REF_TO INT;
  MyVar: INT;
END_VAR

MyVar:= 100;
MyRef:= REF(MyVar); //setting of a reference to a variable
MyRef:= 200;        //there is a new value of 200 in the variable now

Documentation

Reference data type

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