Rockwell Automation 1772-LP3 PLC - 2/30 Programmable Controller Programming and Operations Manual - Manual (Page 266)

Sequencer Instructions
Chapter 15
15Ć3
The Sequencer Output instruction functions in a manner analogous to a
mechanical drum sequencer.
Consider a music box mechanism containing a cylinder with rows of pegs.
As the cylinder turns, the pegs produce tones (output) as they strike the
spring resonators. In this analogy, the presence of pegs on the cylinder wall
are analogous to 1 in bit locations in the sequencer table. As the cylinder
turns continuously through many steps, each step presents a new row of
peg locations. The presence of 1 or more pegs produces a single tone or a
musical chord.
If the cylinder wall containing the pegs could be removed, cut along
its axis to separate the first and last rows, and flattened, the resulting
rectangular surface would be a representation of a sequencer table. The
rows or steps would be numbered from top to bottom; the pegs
representing 1 in bit locations would be numbered accross the top as shown
in Figure 15.3.
The Sequencer Output instructions can control up to 64 outputs with 999
steps.
15.1
Sequencer Output
Instruction
15.1.1
Sequencer Output Analogy