Rockwell Automation AutoMax Enhanced Ladder Language Reference Manual - Manual (Page 268)

13Ć2
13.1 Immediate Input (IN)
Use the Immediate Input instruction to update the program's latched value
corresponding to a global variable with that global variable's current value. Since inputs
are latched at the start of a program scan, the IN instruction is useful for gathering data
that may have changed since the start of a program scan.
While EN is true, the instruction reads the state of a program's global variable (Variable)
at its physical location and updates the latched value with the new value. The newly
updated latched value is used in subsequent instructions as needed.