Siemens SIMATIC S7-200 Manual page 43

"Plain Speaking (2)"
5.
The figure above shows the ladder diagram of the user program with symbolic addressing.
You can, of course, also program with symbolic addresses.
As the operand, you must then enter "S3", for example, you only have to make sure
that this operand has already been entered in the symbol table.
Hardware Software
3.
4.
Basic
Settings
3.
With the menu item
View > Symbolic Addressing
you can switch to the display mode for
symbolic addressing.
4.
If you have selected the symbolic
addressing and changed to LAD, STL or
FBD, the symbolic addresses should now
be visible.
1st Exercise More
Program Exercises
Appendix 39