The method that you use to add a direct variable to your Function Block Diagram will vary depending on whether the diagram already contains an instance of the value.
If your diagram does not already contain an instance of the direct variable that you want to add, refer to Add the First Instance of a Direct Variable to a Function Block Diagram.
If your diagram already contains an instance of the direct variable that you want to add, refer to Add Another Instance of a Direct Variable to a Function Block Diagram.