Omron SYSMAC C Series User Manual

Chapter 1
Introduction to the C20
Overview
PC Basics
This introductory chapter explains why programmable controllers have
become such a valuable part of modernfactories. The SYSMAC-C20 is
described, including its basic components and operating principles.
Programmable controllers, or PCs, evolved as industries sought econo-
mical ways to automate their production lines, particularly those involved
in the manufacturing of equipment and other heavy industry products.
The PCs took the place of relay-based control systems which were
comparatively slower, less reliable, and which presented formidable
wiring and maintenance requirements.
PCs
operate
by
monitoring
input
signals
from
such
sources
as
pushbut-
tons,
sensors,
and
limit
switches.
When
changes
are
detected
in
the
signais,
the
controller
system
reacts,
through
user-programmed
internal
logic,
to
produce
output
signals.
These
signals
operate
the
external
loads
of
the
controlled
system,
such
as
relays,
motor
controls,
indicator
lights,
and
ajarms.
This
type
of
control
system
eliminates
much
of
the
wiring
and
rewiring
that
was
necessary
with
the
conventional
relay-based
system.
Instead,
the
programmed
logic
provides
the
“wiring
network”
which
can
be
changed
as
required
by
simply
reprogramming
the
PC.
Thus
the
automated
processes
of
a
production
line
can
be
controlled
and
modified
at
will,
for
highly
economical
adaptability
to
a
changing
manufacturing
environ-
ment.
Atypical programmable controller has three basic components—an
input/output
section,
a
central
processing
unit
(CPU),
and
a
programming
device.
Input/output section
This
section
consists
of
wiring
and
interfacing
relays
that
connect
the
PC
to the equipment being controlled.
Central processing unit
The
CPU
contains
the
control
circuitry
as
well
as
the
memory
that
stores
the
contro!
plan
that
guides
equipment
operation.
It
is
the
heart
of
the
PC
and
organizes
ail
controller
activity
by
scanning
the
control
plan
along
with
the
status
of
the
inputs
and
executes
specified
commands
to
specified
outputs.

Omron SYSMAC C Series Specifications

General

Brand	Omron
Model	SYSMAC C Series
Category	Controller
Language	English