Concept Behavior

Parameters are Handled by Reference

In Concept all function block parameters are handled by reference, means the blocks receives a pointer to the data of every function block pin and works directly on the connected variable.

Connected variables:

Function Block Code

Therefore in Concept it is up to the function block code to decide whether:

to behave IEC compliant or
to write input data or
to read output data or
not to write output data.