Rockwell Automation 9323-PA1E QUICK START GUIDE APS 6.0 - Manual (Page 28)

Control Basics
2–11
The Processor Operating Cycle
The diagram below indicates the events that occur during the processor operating
cycle. This sequence is repeated many times each second.
Event Description
Input Scan
Input Data File
address data
I:1 0001
F8
0 1
activated
The status of external input circuits is
read. The input data file is updated with
this information.
Program Scan
( )
O:3
0
] [
I:1
0
]/[
I:1
1
The ladder program is executed. The
input data file is evaluated, the ladder
rung is solved, and the output data file is
updated.
Output Scan
Output Data File
address data
O:3 0000 0001
0
Illuminated
The output data file information is
transferred to the external output circuit,
thus energizing or deĆenergizing it.
Communications
( ) Communications with the programming
terminal and other network devices
takes place.
Housekeeping Processor internal housekeeping takes place.