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Rockwell Automation 1785-Lxxx Enhanced and Ethernet PLC-5 Programmable Controllers User Manual

Page 98

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Publication 1785-UM012D-EN-P - July 2005

6-26 Communicating with Remote I/O

Bit Layout Diagrams for the Second Word Allotted to a Remote I/O Rack or an
Extended Local I/O Rack

00

01

02

03

04

05

06

07

08

09

10

11

12

13

14

15

Not Used

Not Used

Inhibit Bits

Reset Bits

N15:15

This Bit:

Corresponds to:

Inhibit Bits

00

first 1/4 rack
starting I/O group 0

01

second 1/4 rack
starting I/O group 2

02

third 1/4 rack
starting I/O group 4

03

fourth1/4 rack
starting I/O group 6

Reset Bits

08

first 1/4 rack
starting I/O group 0

09

second 1/4 rack
starting I/O group 2

10

third 1/4 rack
starting I/O group 4

11

fourth1/4 rack
starting I/O group 6

ATTENTION

When you use a ladder program or the software to
inhibit and reset an I/O rack, you must set or clear the
reset and inhibit bits that correspond to each quarter
rack in a given chassis. Failure to set all the appropriate
bits could cause unpredictable operation due to
scanning only part of the I/O chassis.