Rockwell Automation 1772-L8_LW_LWP_LX_LXP,D17726.5.8 User Manual - Manual (Page 119)

Chapter
8
8-1
Scan Theory
In this chapter you will read about:
scan function
scan time
The processor controls the status of output devices or instructions in
accordance with program logic. Every instruction in your program
requires execution time. These times vary greatly depending upon the
instruction, the amount of data to be operated on, and whether the
instruction is true or false.
As a review from chapter 2, there are two types of scans (Figure 8.1):
I/O scan
Program scan
Chapter Objectives
Scan Function