INTRODUCTION TO PROGRAMMABLE LOGIC CONTROLLERS (PLCs)

2601/201B INDUSTRIAL PROGRAMMABLE LOGIC CONTROLLERS

COURSE OUTLINE

1. Introduction to INDUSTRIAL PROGRAMMABLE

LOGIC CONTROLLERS 8h

2. PLC SYSTEMS 15h

3. SUPERVISORY CONTROL AND DATA ACQUISITION

(SCADA) 15h

4. INDUSTRIAL COMMUNICATION NETWORK 15h

5. CALIBRATION SOFTWARE 13h

GENERAL OBJECTIVES

1. Observe safety regulations and standards that

govern operation of programmable Logic
controllers.

2. Understand different application of industrial

programmable logic controllers.

3. Maintain sequential control and data

acquisition (SCADA) systems.

4. Maintain programmable logic control (PLC)

systems.

Assessment

1. Cat= x/30

2. End of term =y/70

3. Total = x + y

Lecture – Introduction to PLC's

MME 486 – Fall 2006

4 of 47

Programmable Logic Controller

• A programmable logic controller (PLC)
is a specialized computer used to
control machines and process.
• It uses a programmable memory to
store instructions and specific functions
that include On/Off control, timing,
counting, sequencing, arithmetic, and
data handling

Brief History of the PLC

 In what era was the PLC introduced? A; late 1960s

 PLC have evolved over the years. Networking , relay

control, and data- handling capabilities have all vasty
improved since PLCs were first developed. Let’s review
some of the other important moments in PLC evolution!

 The early 1980s brought about the incorporation of

distributed control functions.

 The 1990s brought standardization and open systems

 Ethernet peer to peer networking became accessible from

nearly all PLC manufacturers.

 Ease of redundancy became a standard product

 Very small nano or Pico PLCs arrived

 PLC featuring triple redundancy were introduced for safety

Lecture – Introduction to PLC's

MME 486 – Fall 2006

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The First Programmable Logic
Controllers (PLCs)

• Introduced in the late 1960’s
• Developed to offer the same functionality as
the existing relay logic systems
• Programmable, reusable and reliable
– Could withstand a harsh industrial environment
– They had no hard drive, they had battery backup
– Could start in seconds
– Used Ladder Logic for programming

Lecture – Introduction to PLC's

MME 486 – Fall 2006

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The Need for PLCs

• Hardwired panels were very time consuming
to wire, debug and change.
• GM identified the following requirements for
computer controllers to replace hardwired
panels.
– Solid-state not mechanical
– Easy to modify input and output devices
– Easily programmed and maintained by plant
electricians
– Be able to function in an industrial environment

Process control;

 In

industrial

settings,

process

control

refers

to

the

use

of

aprogrammable

logic

controller (PLC) to automate and regulate equipment or processes. PLCs are digital
devices

that

can

receive,

process,

and

output

signals

based

on

pre-programmed

algorithms.

They

are

commonly

used

to

control

machinery,

manage

large

continuous

processes,

and

monitor

industrial

systems

.PLCs

can

be

integrated

with

sensors,

robots,

and

other

components

to

improve

the

performance,

speed,

precision,

and

automation of industrial systems.

 Process

control

engineers

use

PLCs

to

automate

various

tasks

in

industrial

facilities. For example, they can program PLCs to start and stop machinery, control
the

speed

of

conveyor

belts,

and

open

or

close

valves.

PLC-based

process

control

offers compact, low-cost, and advanced engineering solutions for managing different
types of inputs such as temperature sensor inputs and analog signal inputs.

 PLC

control

is

widely

applied

in

various

industrial

applications

such

as

utility

plants,

chemical

processing,

conveyor

systems,

food

processing,

and

auto

assembly

lines.

It

simplifies

system

design

and

extends

monitoring

capabilities

to

improve

equipment and personnel safety.

 If

you

have

any

specific

questions

about

industrial

process

control

using

PLCs

or

need more information on a particular aspect of this topic, feel free to ask!

The need for Industrial Software Engineering

Process monitoring;

 PLCs also allow for safer, faster, and more accurate completion

of tasks. They are ideal for industries that cannot allow for
the risk of human error or that have more dangerous operations
or equipment.

 The latest generation of PLCs can remotely monitor and control

input/output thanks to an integrated Ethernet port. This allows
the remote controlling of machines by transmitting messages
between electronic devices via Ethernet/IP or Modbus TCP.

 The advantage of remote monitoring lessens the need for an

extensive workforce of supervisors to oversee the running of
these machines. However, you can pair PLCs with a Human Machine
Interface (HMI). This enables users to monitor the health of
the system and manually override controls when necessary.

The need for Industrial Programmable Logic controllers

PLC Integration

 Generally when the PLC is integrated into a process control

or automated control system, all of the components work
together to form a complete control system.

 The system is normally made up of a combination of PLCs,

networks, I/O, software and terminals.

Do you know the difference between a PLC and a PC?

Programmable Logic controller

 Designed for industrial environments

 They can withstand a wide range of temperatures and humidity

 Not affected by electrical noise

 They are programmed in the easily learned relay ladder logic

language.

With terminals for inputs and outputs, and communication ports,
they usually execute a single task in a sequence. The software
for this device allows the user to program and document the
program. Another type of software called a Human Machine
Interface (HMI) allows the user to monitor and control the
process.
Personal computer

Not usually made to withstand an industrial atmosphere, they can
computer in any order and execute several tasks at one time.
These devices have a keyboard, CD drive and monitor.

Lecture – Introduction to PLC's

MME 486 – Fall 2006

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PLC
- Operates in the industrial
environment
- Is programmed in relay
ladder logic
- Has no keyboard, CD drive,
monitor, or disk drive
- Has communications ports,
and terminals for input and
output devices

PLCs Versus Personal Computers

Same basic
architecture

PC
- Capable of executing several
programs simultaneously, in
any order
- Some manufacturers have
software and interface cards
available so that a PC can do
the work of a PLC

Lecture – Introduction to PLC's

MME 486 – Fall 2006

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PC Based Control Systems

Advantages
- Lower initial cost
- Less proprietary hardware
and software required
- Straightforward data exchange
with other systems
- Speedy information processing
- Easy customization

Leading PLC manufacturers

 Siemens- Germany

 Rockwell Automation/ Allen Bradley- USA

 Mitsubishi Electric- Japan

 Schneider Electric- France

 Omron Industrial Automation- Japan

 Emerson(General Electric)- USA

 Keyence- Japan

 Kinco- China

 B & R Industrial Automation

 ABB- Switzerland

 Hitachi

 Panasonic- Japan

 Delta Electronic- Taiwan

 Toshiba

 Phoenix contact- Germany

 LG

 Fuji Electric- Japan

 Honeywell

 WAGO

 Yokogawa Electric - Japan

 Yaskawa Electric Corporation-Japan

 Beckhott

 Unitronics- Israel

 Bosch (Rexroth) - Germany

 Crouzet

 RS Enterprises- India

 General Industrial Controls (GIC)-

India

 Fatek- Taiwan

 Wecon Technology- China

PLC configurations

There are two PLC I/O configurations that commercial
manufacturers offer

 Fixed I/O PLC(integrated or compact)configuration

 Modular PLC Configuration

PLC configurations- CONT’

PLC sizes

Nano; upto 16 I/O points

Micro; more than 16 I/O points

upto 64 I/O points

Small; upto 960 I/O points

Medium; multitasking capability

and controls several processes

Large; Control Management of

several PLC

Advantages of PLCs

 Reliability

 It takes the place of many wires and relays in a conventional relay system. Once a

program is written it can be saved and easily reused or downloaded to other PLCs.

 Flexibility

 Changing the program with PLCs is easier than rewiring a circuit as you would have to do

with a conventional relay controller.

 Lower cost

 Installing PLC is less expensive than installing many relays and wires to complete

circuit.

 Communication capability

 It is capable of communicating with other devices or computer equipment for data

gathering, supervisory control, process parameters, device monitoring, downloading and
uploading programs.

 Faster response time

 Its response time is fast and reliable. It takes only fractions of seconds for the PLC

to execute an operation.

 Easier to troubleshoot

 The ability to watch the PLC scan in real time on a display allows for faster fault

finding and repair of problems that with standard relay systems.

Types of industrial software systems

Human Machine Interface
(HMI)

 The HMI consist of a PC

that communicates with a
PLC using display hardware
where machine status,
alarms, messages, data
entry and diagnostics are
available to the operator
via a graphical display
format.

 Many control processes use

HMI.

 Here

are

some

examples

of

popular

HMI

software

programs

that are available on the market:

1. Siemens

WinCC:

A

scalable

and

customizable

HMI

software

program from Siemens that can be used for a wide range of
industrial applications.

2. Rockwell

Automation

FactoryTalk

View:

A

HMI

software

program from Rockwell Automation that is designed for use
in industrial automation and manufacturing environments.

3. Schneider

Electric

Vijeo Designer:

A

HMI

software

program

from

Schneider

Electric

that

is

designed

for

use

in

industrial automation and process control applications.

4. Pro-face

GP-Pro

EX:

A

HMI

software

program

from

Pro-face

that

is

designed

for

use

in

industrial

automation

and

manufacturing environments.

5. Mitsubishi

Electric

GOT:

A

HMI

software

program

from

Mitsubishi Electric that is designed for use in industrial
automation and process control applications.

1. GE

Cimplicity:

A

HMI

software

program

from

GE

that

is

designed

for

use

in

industrial

automation

and

process

control applications.

2. Wonderware

Intouch:

A

HMI

software

program

from

Wonderware

that

is

designed

for

use

in

industrial

automation and process control applications.

3. Iconics Genesis64: A HMI software program from Iconics that

is

designed

for

use

in

industrial

automation

and

process

control applications.

4. Inductive Automation Ignition: A HMI software program from

Inductive Automation that is designed for use in industrial
automation and process control applications.

5. Beijer

Electronics

X2:

A

HMI

software

program

from

Beijer

Electronics

that

is

designed

for

use

in

industrial

automation and process control applications.

6. AutomationDirect

C-more:

A

HMI

software

program

from

AutomationDirect

that

is

designed

for

use

in

industrial

automation and process control applications.

 SCADA

Supervisory control and data acquisition (SCADA) software is
essential for industrial organizations to control the
processes, monitor real-time data, and communicate system
issues. The software communicates with devices such as
programmable logic controllers (PLCs) to interact with
industrial equipment and processes. SCADA software can be run
virtually, which allows the operator to supervise the
industrial processes even from a distant location. The
software provides real-time data insights through Human
Machine Interface (HMI) to maximize efficiency, reduce
overhead costs, and streamline operations. The software also
warns the operator of any hazardous conditions such as blocked
processes and failing systems.

Types of industrial software systems-CONT’

Programming and configuration Software;

PLC programming software is a software tool that allows users to create, edit, configure
and debug programs for programmable logic controllers (PLCs).

Some examples of PLC programming software are:

•Simatic step7

•Tia portal

•Machine expert basic

•Twido suite

•Ladder editor

•HX CODESYS

•Pro-H

•RSLogix 5000

•WinProLadder

•I-TriLoGi

•WPLSoft

•Micro Ladder

•Open PLC editor

•Do-more Design

Types of industrial software systems-CONT’

 Calibration software

Calibration is an essential process to ensure accurate measurements in various
applications. It allows for the implementation of a correction factor to account for any
discrepancies between theoretical and actual readings.

To calibrate a Programmable Logic Controller (PLC) for analog measurements, such as
force, pressure, electrical current, length, or position, you can follow these general
steps:

1. **Measurement System Design**: An engineer designing a measurement system will examine

the voltage or current provided by the measuring transducer and the "counts" that should
result after the analog input card converts the electrical signal to a number.

2. **Calibration Method**: The calibration method can be applied to any analog measurement.

Let's consider an example where the length of an object is being measured. Assume that a
device has been built that converts the length of the object to numerical readings via an
analog input. The following assumptions are made for this example:

○The object being measured ranges from 2 to 9 inches in length.

○The analog device provides a voltage signal to the analog input card, which is
converted to a number or "counts" by the card.

Types of industrial software systems-CONT’

Calibration software- Cont’

1. The object being measured ranges from 2 to 9 inches in length.

2. The analog device provides a voltage signal to the analog input card, which

is converted to a number or "counts" by the card.

3. **Calibration Routine**: The calibration routine corrects for differences

between theoretical and actual values. It involves comparing the measured
counts with the expected counts for known lengths of the object being
measured. For example, if an object 2 inches in length produces a count of
100 and an object 9 inches in length produces a count of 3900, you can
establish a linear relationship between counts and length.

 By implementing a PLC calibration routine, you can ensure accurate

instrument readings and provide correction factors for precise measurements.

 Please note that specific calibration procedures may vary depending on the

type of measurement and equipment used.

Types of industrial software systems-CONT’

Lecture – Introduction to PLC's

MME 486 – Fall 2006

15 of 47

PLC Architecture

• An open architecture design allows the system to be
connected easily to devices and programs made by
other manufacturers.

• A closed architecture or proprietary system, is one
whose design makes it more difficult to connect devices
and programs made by other manufacturers.

NOTE: When working with PLC systems that are
proprietary in nature you must be sure that any generic
hardware or software you use is compatible with your
particular PLC.

The end
thank you