Rockwell Automation 1775-S5_SR5,D17756.5.5 User Manual PLC-3 FAMILY I/0 - Manual (Page 75)

Chapter
5
5-1
Addressing DH and DH+ Data Transfers
In chapter 4, we described how you can send a single message command or
a message procedure containing a group of commands. This chapter
explains some general rules for specifying data addresses in message
procedures for communicating over a DH or DH+ link.
To transfer data from one DH or DH+ station to another, you program an
assignment command into the scanner. The assignment command enables
you to copy information from a source to a destination. In this chapter, we
use the following abbreviations to denote the parameters that you can
specify as a source or destination for a data transfer:
Parameter: Meaning:
bit
number of a particular bit within the addressed word
fileaddr
logical address of a PLCĆ3 file
filesym
symbolic address of a PLCĆ3 file
offset
number of words between the beginning of the file and the
desired word (offset is zero for the first word of a file)
size
number of words that transfer
wordaddr
logical address of a PLCĆ3 word
wordsym
symbolic address of a PLCĆ3 word
You can use a value or an expression for any of the above parameters in an
assignment command.
When using the above parameters, the scanner interprets values as decimal
(base 10) unless you indicate that they are octal (base 8). Specify an octal
number by starting it with a leading zero. For example, the scanner
interprets 17 as decimal 17, but 017 as octal 17.
Important: An exception to the above rule occurs when addressing a word
in the input or output sections of PLC-3 memory. In these cases, the
scanner normally interprets the word address
wordaddr as an octal number,
regardless of leading zeros. To express an input or output word address as
a decimal value, enclose the word address within parentheses and eliminate
leading zeros.
Chapter Objectives
Addressing Field
Parameters
Interpreting Addresses