31.1.1.2 Mapping by Drag and Drop to I/O Terminals from the
Address Window
Select the [Address] tab to open the [Address]
window.
If the [Address] tab is not displayed in the
Work Space, on the [View (V)] menu, point to [Work Space (W)], and
then click [Address (A)].
Select [Symbol Variable], and for the [Type] select
[Bit Variable].
The list displays addresses whose [Type] equals
[Bit Variable]. In the list, drag "Start" to the instruction
operand you want to map the variable.
Release the mouse where the pointer changes from to .
The address will be mapped and the I/O address (IEC
address) will be displayed.
to 
.