Introduction To The C20; Overview; Pc Basics; Input/Output Section - 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.
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