Input and Output Variables

Between the key words VAR_IN_OUT and END_VAR, all variables are declared that serve as input and output variables for a POU.

Attention

With this variable, the value of the transferred variable is changed (“transferred as a pointer”, Call-by-Reference). That means that the input value for such variables cannot be a constant. For this reason, even the VAR_IN_OUT variables of a function block can not be read or written directly from outside via <functionblockinstance><in/outputvariable>.

Example:

VAR_IN_OUT
 iInOut1:INT; (* 1. Inputoutputvariable *)
END_VAR