This document provides an overview of industrial automation through programmable logic controllers (PLCs). It discusses what a PLC is and how it works, including the main units of a PLC system like the central processing unit, memory, input/output modules, and programming. The document also covers advantages of PLCs over relay logic, common PLC applications, installation/maintenance, troubleshooting, and selecting a PLC. It aims to introduce the basic concepts of PLCs and how they are used for industrial automation.

1. Industrial Automation Through PLC
PRESENTED BY : SYED ATIF CHISHTI
IEEE IEU (Student Branch)

2. CONTENTS
 INTRODUCTION
 PLC VERSUS RELAY LOGIC
 ADVANTAGES AND DISADVANTAGES
 UNIT OF PLC
 CPU PROCESSOR,MEMORY ANDPOWER SUPPLY.
 INPUT/OUTPUT MODULES
 INPUT /OUTPUT DEVICES AND SENSORS
 PLC PROGRAMMING
 PlC USED IN DIFFERENT PROCESS PLANT OF SPF
 PLC INSTALLATION,TROUBLE SHOOTING MAINTENANCE
 SELECTING A PLC
 MANUFACTURES
 OTHER APPLICATIONS(ROBOTS,SCADA System)

3. INTRODUCTION
 A plc is a microprocessor –based specialized computer that carries out control function
of many types and levels of complexity .
 PLC purpose is to monitor crucial process parameter and adjust process operations
accordingly.
 PLC takes the place of much of the external wiring required for control of a process
 The PLC can be operated on the input side by on-off devices such as digital and also
analog input devices
 PLC will operate any system that has output devices that go on and off and also operate
any system with variable output.

4. PLC VS CONTROLLER
Good Things about PLC’s
 Uses Ladder programming language through high end software
 They are highly reliable, fast and flexible.
 They can handle severe conditions such as dust, humidity etc.
 They can communicate with other controllers.
 They are easy to program and troubleshoot.
 They include display units.
 It is for industrial automation.
 Trouble shooting, signal interfacing
 Input/output expandables usually programmed through external PC program
Good Things about Micro Controller
 Design our own signal interfacing
 Machine language use for programming.
 Input/output cannot be expandables.

5. PLC VERSUS RELAY LOGIC
 Before PLC introduced,Relay -type control panel used in
process control.It is large and contains lots of wiring
,interconnections and relays,which can have the
maintenance problems.
 The first PLC system evolved in the late 1960s and early
1970s and these first PLCS were installed in automotive
plants.
 IN 1972 ,the introduction of microprocessor chip increased
computer power for all kinds of automation system s and
lowered the computer cost.
 IN 1980,large electronics and computer companies found
that PLC had become their greatest volume product.

6. PLC RELAY LOGIC

7. 90%
10%
PLC RELAY LOGIC
Present Statistics
PLC VS Relay Logic

8. PLC AS A COMPUTER
 A Plc is a computer ,but a different type from the desk
or lap computer.Micro computers are data processing
computers while PLC is a process control computer.
Data processing
Computer
system
Video
display
terminal
Printer
plotter
Keyboard
Light Pen
Mouse

9. Process control
computer sytem
Motor
Heater
lights
Motion
sensor
Sound
Sensor
Heat
sensor
Light
sensor
Soleno
id
PLC AS PROCESS CONTROL

10. ADVANTAGES
 Flexibility
 Implementing changes and correcting Errors
 Lower cost
 Visual observation
 Speed of operation
 Reliability and Maintainability
 Security
 Ease of changes by reprogramming

11. UNITS OF PLC
 There are four major units of a plc system
1.Central processing unit(CPU)
a.Microprocessor
b.Memory
c.Power supply
2.Programmer /Monitor
3.I/O Modules
4.Racks and chassis

12. Central Processing unit
 The central processing unit (CPU) is the part of a
programmable controller that retrieves,decodes,
stores, and processes information.
 It also executes the control program stored in the PLC’s
memory.
 The CPU is the “brains” of a programmable controller.
It functions much the same way the CPU of a regular
computer does, except that it uses special instructions
and coding to perform its functions.

13. MEMORY
 There are two types of memory in plc
 Read only memory (Rom)
 Random access memory(Ram)
ROM
The programmable read only memory (PROM) chip is similar to
the ROM except it may be programmed once.
The Erasable programmable read only memory (EPROM) is a
PROM that can be erased.The EPROM is erased by ultra violet
light.
The electrically erasable programmable read only memory
(EEPROM) is similar to the EPROM.Instead of UV light
,Electrical signal is applied to erase the program.

14. RAM
 The EEPROM is used in place of RAM.
 EEPROM is the memory for storing ,backing up,or
transferring PLC programs.
 The nonvolatile random access memory (NOVRAM) is
a combination of EEPROM and RAM.
 When the power is about to go off,the contents of the
RAM memory are quickly stored in the EEPROM.
 The stored data can then be read in to the RAM
memory when the power is again restored.

15. MEMORY MAP

16. PROCESSOR
 The processor is the part of the CPU that codes, decodes,
and computes data.The data is in digital pulse form ,is sent
and received.
 Microprocessors power are determine by two factors
Bit size and clock speed.
There are 4,8,16,32 and 64-bit microprocessor ,which
manipulate data 4,8,16,32 or 64 bits at a time.
Clock speed determines how quickly a microprocessor
executes instruction
Clock speeds range from a low of 1 megahertz(MHZ) to
over 1 giga hertz (GHZ)

17. MICROPROCESSOR BIT SIZE CLOCK SPEED
8085 8-BIT 1 MHZ
8086 16-BIT 4.77 MHZ
80186 16 BIT 8 MHZ
80286 16-BIT 12.5 MHZ
80386 32-BIT 33 MHZ
PENTIUM 32-BIT/64 BIT 1.2 GHZ

18. POWER SUPPLIES
 The power available in most plants is 220 volts
alternating current (AC) at 60 HZ.Most PLC operate
on +5 and -5 volts DC.
 The circuitry is needed to convert 220 v AC input to
the required 5 volt DC values.
LINE
CONDITIO
NER
Rectifi
er
Filter Regula
tor
Back
up
battery

19. Input Modules
 The input module perform four task electronically
1.It senses the presence or absence of an input signal at
each of its input terminal
2.It converts the input signal for high to a DC level
usable by the modules electronic circuit.
3.The input module carries out electronic isolation by
electronically isolating the input module output from
its input.
4.Its electronic circuit must produce an output via
output logic to be sensed by the PLC CPU.

20. INPUT MODULE

21. Input Device /Sensor
Push button
LIMIT SWITCH

22. PHOTO ELECTRIC SYSTEM
TOGGLE TYPE SWITCHES

23. LEVEL SWITCHES
PRESSURE SWITCHES

24. Input Analog Devices
POTENTIOMETER
LVDT LINEAR VOLTAGE
DIFFERENTIAL TRANSFORMER

25. Thermocouple
Thermistor
Photodiode
Turbine

26. OUTPUT MODULES
 A DC signal from the CPU is converted through each
module terminal to a usable output voltage ,either AC
or DC.
 A signal from the CPU is received by the output
module if the cpu signal code matches the assigned of
the module.the module section will turned on.
 Isolation is necessary to the output of the cpu so that
any erratic voltage surge from the output device does
not get back in to the CPU and cause damage.

27. OUTPUT MODULE

28. Output ON/OFF Devices/sensor
ELECTRICAL SOLENOID
ELECTROMECHANICAL RELAY

29. OUTPUT ANALOG DEVICES
STEPPER MOTOR
SERVO MOTOR

30. HOW PLC OPERATES
 Scan Cycle
 Over head
 Input scan
 Logic execution
 Diagnostic & Communication
 Output scan

31. Basic Instruction
Operational details vary widely between different PLC manufactures.
 Positive Logic
True=Logic 1= input energized
False=Logic 0=input not energized
 Negative Logic
True=Logic 0= input not energized
False=Logic 1=input energized
 Normally Open
(XIC) True if Closed
 Normally Closed
(XIO) True if open
 On Timer
 OFF Timer
 Retentive Timer
 Output Latch (OTL)
 Output Unlatch(OTU)
 Jump to Sub Routine(JSR)

32. SCAN PROCESS

33. DATA FLOW OVERVIEW

34. INPUT/OUTPUT TABLE BIT

35. SCAN PATTERN

36. PLC PROGRAMMING
There are five types of PLC programming which are
normally used.
1.Ladder logic Diagram
2.Function Block Diagram(FBD)
3.Boolean Language
4.Structured Text(ST)
5.Instruction List(IL)

37. LADDER LOGIC DIAGRAM
The ladder diagram has two active functional lines.The
format of control ladder diagrams is
1.All coils,pilot lights and outputs are on the right
2.An input line can feed more than one output.so connect in
parallel.
3.Switches and contacts are inserted on the lift side.
4.Switches and contacts may be multiple contacts in
series,parallel
5.Lines are numbered consectively downward on the left.
6.Every connection node is given a unique identification
number
7.Output can be identified by function on the right

38. Comparing Programming Language

39. Normally Open Switch

40. Normally Close Switch

41. OUTPUT COIL

42. STATUS BIT EXAMPLES

43. STATUS BIT EXAMPLES

44. LADDER RUNG

45. LADDER RUNG
OutPut Activated

46. Programming Of Vertical Contacts

47. Programming For Different Scan
Patterns

48. Drilling Process Scenario

49. After the Process

50. LADDER LOGIC

53. Enter the Ladder Diagram

54. RSLogix Main Screen

55. Modes Of Operation

56. Variation of the Run Mode

57. PLC INSTALLED IN DIFFERENT MACHINES
TECHNE

58. BATTENFELD FISHER

59. BEKUM

60. PARKER

61. KAIMEI

62. AKEI

63. BATTENFELD

64. TOSHIBA

65. NETSTAL

66. SIEMENS SIMATIC PLC S7-400

67. Examples of Application
 Bottle Filling Station

68. Examples of Application
 Product Counter

69. Examples of Application
 Traffic Lights Controling

70. Examples of Application
 Liquid Level Monitoring

71. Examples of Application
 Automatic Watering System

72. Examples of Application
 Warehouse Temperature Controlling

73. PLC Installation
These are the factors which should be considered to ensure continuous ,reliable operation of PLC system
after installation.
1.Enclosure:
The PLC can be installed in the open ,NEMA(National electrical manufacturing association )type metal
enclosure.
2.Temperature:
The PLC has upper and lower temperature operationg limit normally 0 c to 60 c.
3.Moisture,Dust and Corrosive Atmosphere:
PLC may be required to operate in an area of high humidity,less moisture and dust.
4.Vibration:
Vibration also cause CPU failure and reduce the life of Plc equipment.
5.Proper Electriacal grounding:
Proper electrical grounding of the wiring of the equipment and cabinets is essential for proper
equipment operation.
6.Suppressor:
Suppression is the technique to absorbs the inductive –caused electrical disturbance.These electrical
disturbances in the air can be reduced by the use of shielded interconnecting cables.
7.Master control relay:
Master relay control system is used to safety shut down of the PLCoperation.When on the safety
shutdown allows the PLC to operate and when deenergi

74. Testing
Testing can be done in any one of three modes
1.PLC can be tested as without attaching any wiring to
the I/o module.
2.It may be tested with a simulator
3.It may be tested after it is hooked up to the system to
operate.

75. Troubleshooting Of PLC
Enter 1
use program loader
and retest processor
Turn to run position
Did fault
Clear
Resume Normal
operation
Enter 2
Disconnect
I/O Flat
cable at
processor
Probable
cause
:defective
I/O Interface
Replace
Processor
Initialize and
load
program
Replace I/O
flat cable
did
fault
clear
Resume
Normal
Operation
Resume
Normal
operation
Reconnect
I/O flat cable
to Processor
Disconnect
all racks
from I/O
Flat cable
Did
Fault
Occur
connect one
I/O Rack at a
time untill
fault occur
A

76. PLC MAINTENANCE
1.Periodically check the tightness of I/O module
terminal screws
2.Moisture and corrosive atmosphere can cause poor
electrical connection.Check periodically for corrosion
of connecting terminal.
3.Make sure that components are free of dust.Proper
cooling is required for Plc.
4.Replace the PlC back up batteries once in a year.

77. Selecting a Plc
These are the factors which have to considered in
selecting a PLC.
1.Cost
2.Service abilitiy/Support
3.Flexibility/Expandability
4.Training /Documentation.

78. MANUFACTURES
 ABB Automation
 Control Microsystems
 CTC Parker Automation
 Intelligent Instruments
 Mitsubishi Electric Automation
 Moeller Corp.
 Omega Engineering
 Schneider Electric
 Siemens Energy & Automation
 Toshiba International Corp.

79. OTHER APPLICATION
SCADA SYSTEM

80. 80

81. Thank You