Rockwell Automation 9323-PA1E USER MANUAL APS 6.0 - Manual (Page 119)

Documenting Ladder Programs
7–3
Address Comments
Address comments help to identify the type of mechanism (pilot light or push
button) associated with the address. The address comment can consist of up to 5
lines, with up to 10 ASCII characters in each line. All instructions having the same
address will automatically have the same address comment.
An address comment need not be unique. The same comment can be applied to
instructions having different addresses. Address comments are internally associated
with the instruction address.
Symbols
You create these identifying “labels” to serve as substitutes for addresses. Once an
address/symbol definition exists, you can enter the address or symbol when you are
prompted for an address while programming.
All instructions having the same address automatically have the same symbol. A
symbol is unique. The same symbol cannot be applied to different addresses.
An instruction can have a symbol in addition to a rung, instruction, or address
comment.
A symbol can consist of up to 10 characters. Letters are displayed as all caps.
Spaces are underlines (__). Note that you cannot begin a symbol with a numeral (0
to 9).
Note Do not use delimiters “/”, “,” “=,” “;”. Constants cannot have symbols
associated with them.