Rockwell Automation 1775-S4B,D17756.5.3 User Manual SCANNER/MSG HND - Manual (Page 73)

Using Symbols and Expressions
in Report Generation
Chapter 8
8Ć5
The procedure @SLAVE can use and alter B and any other interprocedural
user symbol declared in @MASTER, but @SLAVE does not recognize
procedural user symbols declared in @MASTER.
Refer to the next section for a discussion on the assignment statements.
CAUTION: In using user symbols, note the following:
Do not use the same variable(s) to declare a procedural and an
interprocedural user symbol within the same procedure, unpredictable
results could occur.
Do not use the same variable(s) to delare numeric or string user symbols
and labels within the same procedure, unpredictable results could occur.
Do not cycle power on the PLC-3 processor chassis or enter [CTRL] X
on your keyboard while a procedure is executing, you will erase all user
symbols from PLC-3 memory.
An assignment statement assigns a value to an address or a variable.
Report generation uses the following symbols in assignment statements:
Symbol Function
= Assigns the numeric value on the right to the variable or address
on the left. If a user symbol is on the left, it is defined to be a
procedural symbol.
Example: A = 10
== Assigns the numeric value on the right to the variable or address
on the left. If a user symbol is on the left, it is defined as a
interprocedural symbol.
Example: B == l00
=? Assigns the string value on the right to the variable or address on
the left. Only a user symbol can appear on the left side of a string
assignment.
Example: CHAR =? `ENTER A CHARACTER'
==? Assigns the string value on the right to the variable on the left. If
a user symbol is on the left, it is defined as a interprocedural
symbol.
Example: CHAR ==? `ENTER TEMPERATURE READING'
8.3.1
Assignment Statements