The Role of the PC
Section 1-2
1-1 Control Systems
A
Control System is the electronic equipment needed to control a particular pro-
cess. It may include everything from a process control computer, to the factory
computer, down through the PCs, and then on down through the network to the
I/O devices: control components like the switches, stepping motors, solenoids,
and sensors which monitor and control mechanical operations.
Process Control Computer
Factory Computer
PCs
PC
PC
PC
I/O devices
A
Control System can involve very large applications where many different mod-
els of PC are networked together or it could be an application as small as a single
PC controlling a number of output devices.
1-2 The Role of the PC
The PC is the part of the Control System that directly controls the manufacturing
process. According to the program stored in its memory, the PC accepts data
from the input devices connected to it and uses this data to monitor the con-
trolled system. When the program calls for some action to take place, the PC
sends data to the output devices connected to it to cause that action to take
place. The PC may be used to control a simple, repetitive task, or it may be con
-
nected to other PCs or to a host computer in order to integrate the control of a
complex process.
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