A function block is a POU which provides one or more values during the procedure.

As opposed to a function, a function block provides no return value.

⮫ “Function”

A function block declaration begins with the keyword FUNCTION_BLOCK. Regard the recommendations on the naming.

⮫ “Recommendations on the naming of identifiers”

Reproductions or instances (copies) of a function block can be created.

⮫ “Function block instances”

The call of a function block is done via a function block instance.

⮫ “Calling a function block”