All variable symbols and constant expressions are entered in FBD diagrams using small boxes. Press the following button in the FBD toolbar for inserting a variable tag:
|Insert variable: In this mode, the mouse is used for inserting variable tags. Click in the diagram and drag the new variable to the wished position.|
Double click on a variable tag to open the variable selection box and either select the symbol of the wished variable or enter a constant expression.
Variables tags must then be linked to other objects such as block inputs and outputs using connection lines.
You can resize a variable box vertically in order to display together with the variable name its tag (short comment text), its description text, plus its I/O location it the variable is mapped to an I/O channel. The variable name is always displayed at the bottom of the rectangle: