Rockwell Automation 1775-S4B,D17756.5.3 User Manual SCANNER/MSG HND User Manual
Page 77
Using Symbols and Expressions
in Report Generation
Chapter 8
8Ć9
The 1775-S4B scanner uses areas 5 and 6 of PLC-3 memory to store
information about system symbols.
Area 5 of PLC-3 memory is the message area which stores the contents of
all messages. As we discussed in chapter 7, the PLC-3 processor can store
data under different sections of this area. These different sections include:
Report generation procedures
Rung
comments
Terminal or macro commands
Data highway procedures
Assistance
messages
When you use the edit command to create a procedure, the PLC-3
processor stores the contents of the procedure under one of these sections.
You can address these sections by using the following extended addressing
format:
E5.
The character E5 denotes the message area. The context value can be 1
thru 15. The following values correspond to each of the message sections:
1 for report generation
2 for rung comment
3 for terminal or macro commands
4 for data highway
5 for assistance
As an example, the following address corresponds to report generation
procedure number 57:
$E5.1.1.57 or $E5.1.1.57.0
You will notice that the symbol table lists the extended address for each
procedure.
Area 6 of PLC-3 memory stores the names and corresponding memory
address for all system symbols. When you use the edit or create commands
to create a procedure or symbolic address, the 1775-S4B scanner stores the
name and the memory address for the system symbol in this area. When
the 1775-S4B scanner executes a procedure or uses a symbolic address, it
looks up the name in this area to find the extended address of the system
symbol. It then can execute the procedure or find the memory location for
the symbolic address.
8.4.2
Memory Storage for
System Symbols