Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) - Manual (Page 111)

Chapter 6
Programming Overview
6–14
Connecting Blocks
Blocks of input and output instructions can be connected in series and
parallel as well.
Example – Series Block Connection
a e
b
c
d
In the above example, two blocks of information are connected in series.
Either A or B, and C or D provides a true logical path. For instruction list
programming, the ANB instruction represents this connection. (See page
8–12.)
Example – Parallel Block Connection
a b e
c d
In the above example, two blocks of information are connected in parallel.
Either A and B, or C and D provides a true logical path. For instruction list
programming, the ORB instruction represents this connection. (See page
8–12.)
Nested Branching
Input and output branches can be “nested” to avoid redundant instructions, to
speed-up controller evaluation, and to provide more efficient programming.
A “nested” branch is a branch that starts or ends within another branch. You
can nest branches up to four levels deep.