Rockwell Automation 1775-KA PLC-3 Communication Adapter Module User Manual - Manual (Page 81)

Message Procedure Commands
Chapter 6
6Ć3
copies the value of user symbol US_5 into word 24 (octal) of input file
12.
Modifiers
Several modifiers may be added to the basic assignment command. These
modifiers affect three aspects of the assignment:
Scope of assignment
Priority level of Data Highway message
Type of command message transmitted
Scope of Assignment
A double equals sign (==) can also be used for the assignment command.
The extra equals sign modifies the scope of an assignment involving a
user symbol. If the destination of the assignment is a user symbol, the
double equals sign defines the destination to be an interprocedural user
symbol. With the single equals sign, the destination becomes a procedural
user symbol.
For example, the statement
US_2==6
defines US_2 to be an interprocedural user symbol and assigns to it the
value 6.
Do not use the double equals sign (==) with anything other than a user
symbol as the destination.
Message Priority
Data Highway messages may be either one of the following priority
levels: