Rockwell Automation 1772-LP3 PLC - 2/30 Programmable Controller Programming and Operations Manual - Manual (Page 317)

Addressing
Appendix A
AĆ10
Figure A.7
Assigning I/O Rack Numbers with 1Ćslot Addressing
Н Н
Н
Assigned
I/O rack number 1
Assigned
I/O rack number 2 I/O Group No.
01 23 45 67 01 23 45 67
Earlier (Figure A.1), we showed how the 5-digit input or output instruction
is associated with a particular I/O module terminal. Now, with two I/O
racks you use the instruction address to identify which racks you are
communicating with.
Figure A.8 illustrates addressing two modules, each in the same I/O group
number but in different assigned racks of a single I/O chassis.