Symbols; Overview - Omron CJ2 CPU UNIT SOFTWARE User Manual

5-5

Symbols

5-5-1

Overview

Symbols

Symbol Tables
I/O memory area addresses or constants can be specified using character strings by registering the
character strings as symbols. Register the symbols in the symbol tables of the CX-Programmer.
Programming with symbols enables programming with names rather than having to be aware of the
actual addresses.
Symbol tables are saved in a CX-Programmer project file (.CXP) along with other parameters, such
as the user program and I/O tables.
Conditions for Using Symbols
Whether using symbols is required or optional depends the programming language as well as
whether the symbol is used inside or outside of a function block, as given in the following table.
Program element
Programming outside function blocks
Programming inside function blocks (Inside
function blocks, symbols are called "vari-
ables.")
CJ2 CPU Unit Software User's Manual
5 Understanding Programming
Programming language
Ladder diagram
ST
SFC
Ladder diagram
ST
Specifying symbols
Optional
Required
Optional
Required
5-47
5