Rockwell Automation 1775-KA PLC-3 Communication Adapter Module User Manual - Manual (Page 157)

Network and Application Layer Protocols
Chapter 12
12Ć10
ADDR (address)
The address field in command messages can be in one of the following
formats:
PLC/PLC–2 addressing format
Symbolic addressing format
Logical addressing format
Physical addressing format
The PLC/PLC–2 addressing format applies to PLC/PLC–2 type
commands transmitted to the 1775–KA module. Use this addressing
format whenever you have established a PLC–3 input file to imitate
PLC/PLC–2 memory (section titled PLC/PLC–2 Stations, chapter 3).
The ADDR (address) field is a 2–byte address field sent low byte first.
PC programs use logical addressing to specify octal bytes. To generate a
protected/unprotected read/write command, use that same octal addressing
to format the ADDR field as shown in Figure 12.4. For a block read/write
command, always set the least significant bit to 0 to select the low byte of
the word. To allow PC read/write commands to the computer, set up a file
in the computer to be addressed in this same way as if it were a PC data
table.