Rockwell Automation 1772-LV Mini-PLC - 2/15 Programmable Controller (Series B) Programming and Operations - Manual (Page 68)

Advanced Instruction Set
Chapter 6
6Ć11
Function: Used where I/O modules interface with I/O devices that operate in a
shorter time period than the processor scan.
Immediate Input Update
Symbol: -|I|-
Purpose: Updates one input image table word from one input module group in
advance of the normal I/O scan sequence.
Syntax: Programmed at the condition side of the logic rung just before inputs
in the module group are examined in the program (Figure 6.5).