Rockwell Automation 1772-LV Mini-PLC - 2/15 Programmable Controller (Series B) Programming and Operations - Manual (Page 10)

An Introduction to Programmable
Controllers
Chapter 2
2Ć3
Figure 2.3
The Four Major Sections of a Programmable Controller
10719-I
Power Supply
Processor
Information
Input Devices
Limit, Proximity,
Action
(Decision Making)
w
Pressure,
Temperature
Switches
Push Buttons
Logic
BCD
A/D
w
w
w
w
Output Devices
Solenoids w
Motor Starters
Indicators
Alarms
Logic
BCD
D/A
w
w
w
w
w
w
Power Supply
The power supply provides a low level DC voltage source for the electronic
circuitry of the programmable controller. It converts the higher level line
voltages to low level logic voltages required by the programmable controller’s
electronic circuitry.
Input Section
The input section serves four very important functions:
Termination
Indication
Conditioning
Isolation
Termination
The input section provides terminals for the field wiring coming from the
sensing devices on the machine.