Programmable Logic Controllers, Hardware, Programming, Automation
Please subscribe to my YouTube Channel for best training lectures:
https://www.youtube.com/channel/UCRkUJFOsyZG1E1LDWzUr_hw/playlists?view_as=subscriber
Service industry internship (2016) report (plc traning)iqtadar ali gilani
This is report of my internship at SERVICE INDUSTRIES (GUJRAT). I got traning related of "PLC" specially (MITSUBISHI PLC). This report contains basics of "PLC" hardware & programming.
A presentation made at A 2-day Annual Symposium, organized by Electrical/Electronic Engineering Department, FUTO, at School of Engineering and Engineering Technology (SEET) Complex Auditorium, FUTO, Imo State. (August 18, 2016)
Service industry internship (2016) report (plc traning)iqtadar ali gilani
This is report of my internship at SERVICE INDUSTRIES (GUJRAT). I got traning related of "PLC" specially (MITSUBISHI PLC). This report contains basics of "PLC" hardware & programming.
A presentation made at A 2-day Annual Symposium, organized by Electrical/Electronic Engineering Department, FUTO, at School of Engineering and Engineering Technology (SEET) Complex Auditorium, FUTO, Imo State. (August 18, 2016)
This Presentation provides detail description PLC basics, architecture, Programming with Case studies. Quizzes are also included in between the topics in order to measure the Learning.
Summer Internship Report For PLC Programming of Traffic light through Ladder ...Aman Gupta
For free download Subscribe to https://www.youtube.com/channel/UCTfiZ8qwZ_8_vTjxeCB037w and Follow https://www.instagram.com/fitrit_2405/ then please contact +91-9045839849 over WhatsApp.
An industrial PLCs system is used for the development of the controls of machinery. This paper describes the PLCs systems in terms of their architecture, their interface to the process hardware, the functionality and the application development facilities they provide. Some attention is also paid to the industrial standards to which they abide their planned evolution as well as the potential benefits of their use. Ladder Logic is a graphical programming language, initially programmed with simple contacts that simulates the opening and closing of relays. Ladder Logic programming has been expanded to include functions such as Counters, Timers, shift Registers and math operations. Ladder logic is a method of drawing electrical logic schematics. It is now a graphical language very popular for programming Programmable Logic Controllers (PLCs). It was originally invented to describe logic made from relays. The name is based on the observation that programs in this language resemble ladders, with two vertical "rails" and a series of horizontal "rungs" between them.
In this session you will learn:
Programmable Logic Controller(PLC)
Types of PLC’s
PLC architecture
Scan cycles
Scan patterns
PLC programming
Ladder diagram programming
Latch and Unlatch
DCS architecture
For more information, visit: https://www.mindsmapped.com/courses/industrial-automation/complete-training-on-industrial-automation-for-beginners/
Seminar Presentation on Programmeble Logic Controller , By an Engineering Student For doing Professional Presentation like Business Presentation, Industrial Use
This Presentation provides detail description PLC basics, architecture, Programming with Case studies. Quizzes are also included in between the topics in order to measure the Learning.
Summer Internship Report For PLC Programming of Traffic light through Ladder ...Aman Gupta
For free download Subscribe to https://www.youtube.com/channel/UCTfiZ8qwZ_8_vTjxeCB037w and Follow https://www.instagram.com/fitrit_2405/ then please contact +91-9045839849 over WhatsApp.
An industrial PLCs system is used for the development of the controls of machinery. This paper describes the PLCs systems in terms of their architecture, their interface to the process hardware, the functionality and the application development facilities they provide. Some attention is also paid to the industrial standards to which they abide their planned evolution as well as the potential benefits of their use. Ladder Logic is a graphical programming language, initially programmed with simple contacts that simulates the opening and closing of relays. Ladder Logic programming has been expanded to include functions such as Counters, Timers, shift Registers and math operations. Ladder logic is a method of drawing electrical logic schematics. It is now a graphical language very popular for programming Programmable Logic Controllers (PLCs). It was originally invented to describe logic made from relays. The name is based on the observation that programs in this language resemble ladders, with two vertical "rails" and a series of horizontal "rungs" between them.
In this session you will learn:
Programmable Logic Controller(PLC)
Types of PLC’s
PLC architecture
Scan cycles
Scan patterns
PLC programming
Ladder diagram programming
Latch and Unlatch
DCS architecture
For more information, visit: https://www.mindsmapped.com/courses/industrial-automation/complete-training-on-industrial-automation-for-beginners/
Seminar Presentation on Programmeble Logic Controller , By an Engineering Student For doing Professional Presentation like Business Presentation, Industrial Use
AFiredetectionandalarmsystemisnumberofdevicesworkingtogethertodetectandwarn
people through visual and audio appliances when smoke,fire,CO or other emergencies are present.
GSM Based Versatile Robotic Vehicle Using PIC Microcontroller Report.Abee Sharma
This project is designed to develop as a robotic vehicle that can be controlled by a cell phones. DTMF commands from a phone send to another cell phone which is mounted on the robotic vehicle. These commands are fed to a PIC microcontroller of 8-bit architecture to operate the vehicle movement through motor interface.
Conventionally Wireless-controlled Robots Use Rf Circuits, Which Have Limited Working Range, Limited Frequency Range and Limited Control. Use of a Mobile Phone for Robotic Control Can Overcome These Limitations. It Provides the Advantage of Robust Control, Working Range as Large as the Area of the Service Provider, No Interference with Other Controllers. Although the Appearance and Capabilities of Robot Vary Vastly, All Robots Share Feature of a Mechanical, Movable Structure Under Some Form of Control. The Control of Robot Involves Three Distinct Phases: Perception, Processing and Action. Generally, the Preceptors Are Sensors Mounted on the Robot, Processing is Done by the On-board Microcontroller or Processor, and the Task is Performed Using Motors or with Some Other Actuators. In This Project the Robot is Connected to Gsm mobile (using DTMF technology) Which is Controlled by User Mobile Phone. With the Help of Commands We Can Move Our Robot in Desired Direction as Per Our Requirement.
COMPONENT USED:
* DTMF DECODER
* 8-BIT PIC MICROCONTROLLER
* CELL PHONES
* DIODES
* BATTERY(6-VOLT)
* DC MOTOR
* WHEELS ETC.
Project By Abhi Sharma.
This book guides the beginner to start up with Embedded C programming using MP LAB . This Book covers all interfacing examples with pic micro controller and guides beginners to develop projects on PIC micro controller
PIC-MICROCONTROLLER TUTORIALS FOR BEGINNERSVISHNU KP
PIC microcontroller programming based on micro c IDE.Those who really want to build a base in microcontroller programming,just keep going through this. ;) :)
Difference between micro controller and PLC, Introduction to PLC.,
PLC structure at glance,
PLC structure,
I/O processing,
Ladder Diagram Fundamentals,
PLC for industrial Prose cc control,
Selection criteria for PLC
For free download Subscribe to https://www.youtube.com/channel/UCTfiZ8qwZ_8_vTjxeCB037w and Follow https://www.instagram.com/fitrit_2405/ then please contact +91-9045839849 over WhatsApp.
Programmable Logic Controller (PLC) is a specialized computing system used for control of industrial machines and processes.
PowerPoint Presentation on Industrial Automation In which we discuss About PLCs, SCADA,HMI,VFD and various tools of Automation which is used in Industries.
Like Comment & Share
Advanced Anti surge Control System for Turbine Driven Centrifugal CompressorsArslan Ahmed Amin
Advanced Anti surge Control System for Turbine Driven Centrifugal Compressors
Please subscribe to my YouTube Channel for best training lectures:
https://www.youtube.com/channel/UCRkUJFOsyZG1E1LDWzUr_hw/playlists?view_as=subscriber
Visual Analysis of Non Linear Systems, Chaos, Fractals, Self Similarity
Please subscribe to my YouTube Channel for best training lectures:
https://www.youtube.com/channel/UCRkUJFOsyZG1E1LDWzUr_hw
ELECTRICAL AND INSTRUMENTATION ENGINEERING COURSE
Lect 4 power system protection
Please subscribe to my YouTube Channel for best training lectures:
https://www.youtube.com/channel/UCRkUJFOsyZG1E1LDWzUr_hw
Lect 3 electric power generation, transmission and distributionArslan Ahmed Amin
ELECTRICAL AND INSTRUMENTATION ENGINEERING COURSE
Lect 3 electric power generation, transmission and distribution
Please subscribe to my YouTube Channel for best training lectures:
https://www.youtube.com/channel/UCRkUJFOsyZG1E1LDWzUr_hw
ELECTRICAL AND INSTRUMENTATION ENGINEERING COURSE
Lect 2- Electric Machines
Please subscribe to my YouTube Channel for best training lectures:
https://www.youtube.com/channel/UCRkUJFOsyZG1E1LDWzUr_hw
Presentation on Thermal Imaging
Please subscribe to my YouTube Channel for best training lectures:
https://www.youtube.com/channel/UCRkUJFOsyZG1E1LDWzUr_hw
ELECTRICAL AND INSTRUMENTATION ENGINEERING COURSE FOR OIL AND GAS FACILITIES
Please subscribe to my YouTube Channel for best training lectures:
https://www.youtube.com/channel/UCRkUJFOsyZG1E1LDWzUr_hw
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
2. Personal
Introduction
Engr. Arslan Ahmed Amin is a professional Electrical and
Instrumentation Engineer serving Pakistan’s pioneer Oil and Gas
Organization, Pakistan Petroleum Limited. He obtained his Bachelor's
degree in Electrical Engineering from the prestigious University of
Engineering and Technology, Lahore in 2010 and started his
professional career with Pakistan Petroleum Limited. He has served
this organization for 06 years and achieved lots of accomplishments in
the development of the systems of newly installed 210 MMSCFD gas
compression facility. He actively contributed his services in
commissioning, testing, maintenance and upgradation of the E&I
systems. He completed his Master’s in Business Administration
(M.B.A.) in 2014 from Virtual University of Pakistan, Lahore through
distance learning and afterwards obtained Masters (M.Sc.) in
Electrical Engineering from University of Engineering and Technology,
Lahore in 2015.
3. P.H.D. Electrical Engineering (University of Engineering
and Technology, Lahore) In progress.
M.Sc. Electrical Engineering (University of Engineering
and Technology, Lahore)
M.B.A. Online (Virtual University of Pakistan, Lahore)
B.Sc. Electrical Engineering with Honors (University of
Engineering and Technology, Lahore)
Education
4. 06 years’ experience in industrial process controls and
electrical power systems domain with Pakistan
Petroleum Limited (PPL) in CMMS (SAP) environment.
Experience in commissioning, testing and maintenance
roles of latest systems regarding Power Generation,
Field Instrumentation, Distributed Control System,
Safety Instrumented System, Gas Turbines, PLCs,
Analyzers, SCADA, Well Head Control Panels and Utility
packages.
Experience
5. ‘DCS Troubleshooting Practices’ by Haward Technology Middle
East from 16th to 20th May 2016.
‘Protective Relays Applications in Power System’ by Haward
Technology Middle East from 04th to 08th April 2016.
‘Circuits and Electronics’ from Massachusetts Institute of
Technology (MIT) USA.
‘Project Management’ from Virtual University of Pakistan
(VU).
‘Production and Operations Management’ from Virtual
University of Pakistan (VU).
‘Conflict Management’ from Virtual University of Pakistan
(VU).
‘Crisis Management’ from Virtual University of Pakistan (VU).
Professional
Courses
6. QMS 9001, ISO 14001 EMS and OHSAS 18001, ERP System, Cost
of Quality, Productivity Improvement Techniques, Process
Safety Management, Hazard Identification and Risk
Assessment, HAZOP, SIL systems, Occupational health and
Safety, Permit to work system, Safety Modules
(Complete), Communication Skills, Team Work Skills, Decision
Making Skills (Organized by PPL)
SAP System (R3P version) Maintenance Work Orders Processing,
Contracts Management, Spares and Material.
‘Instrumentation and Controls Fundamentals’ from OMS
Institute of Management and Technology, Lahore.
Installation, calibration and maintenance of Fire and Gas
detectors by Det-tronics.
Generation, Transmission and Distribution at WAPDA
Engineering Academy Faisalabad.
Professional Trainings
7. Among Top 10 students in the session of 240 students in B.Sc.
Electrical Engineering.
Received Dean’s Honor Role award in consecutive five semesters
for excellent academic performance in B.Sc. Electrical
Engineering.
Overall Topped in F.Sc. in Board of Intermediate and Secondary
Education, Faisalabad 2006.
Winner of Quaid-e-Azam Scholarship.
Gold medal winner in District Science Quiz Competition Faisalabad.
Represented as ‘Talent of Pakistan Youth’ in China in 2007 by
Ministry of Youth, Pakistan.
Academic
Achievements
8. P L C C O U R S E
Introduction
PLC history
PLC functions
PLC selection
Logic Gates in PLC
Combination of Gates
Simple Logic Examples
Exercise
9. What is a PLC?
A PLC is a device that was invented to replace the
necessary sequential relay circuits for machine control.
The PLC works by looking at its inputs and depending
upon their state, turning on/off its outputs.
The user enters a program, usually via software, that
gives the desired results.
10. What is a PLC?
For example, let's assume that when a switch
turns on we want to turn a solenoid on for 5
seconds and then turn it off regardless of how
long the switch is on for. We can do this with a
simple external timer. But what if the process
included 10 switches and solenoids? We would
need 10 external timers. What if the process also
needed to count how many times the switches
individually turned on? We need a lot of external
counters.
11. PLC History
In the late 1960's PLCs were first introduced.
The primary reason for designing such a device was
eliminating the large cost involved in replacing the
complicated relay based machine control systems.
12.
13.
14.
15.
16.
17.
18. PLC History
Bedford Associates (Bedford, MA) proposed something
called a Modular Digital Controller (MODICON) to a
major US car manufacturer.
The MODICON 084 brought the world's first PLC into
commercial production.
19. Programmable Logic Controller
( P L C ) – T Y P E S
Modular:
Capacity and functionality can be
added as required and then
removed to be used elsewhere.
Industrial:
Suitability for the temperature,
humidity, vibration and voltage
variation and design for 24 hour
operation.
20. Benefits of PLC
Safe operation of plant
In emergency, automatically shutdown the plant in fail
safe condition
In startup check the prerequisite & then permit to start
Logging the event.
21. Benefits of PLC
High reliability
Flexible control
Easily modified
Easy troubleshooting
Reduced space requirement
Revisable
Lower cost
Modularity
22. PLC Selection
Safety
Reliability and maintainability
Availability
Flexibility
Cost
Speed of operation
Security
Space
Events logging
23. Safety
For the term of safety, there are
numerous definitions that have been
worked out the different boards. All
definitions have in common that safety
means a sufficient protection form
danger. In the DIN 31 000 standard
document, part 2 safety is defined as a
situation in which the risk is not
higher than the risk limit. This also
means that absolute safety cannot be
achieved in technology.
24. Safety
Safety related controls are needed for trains, lifts, escalators,
burners etc. the safe controls must be designed in a way that
any component fault and other imaginable influences do not
cause dangerous states in the plant.
25. Safety
The safe state is the state to which a system can be put out of its
current operational state and which has a system specific lower
hazard potential than the operational state. The absolutely safe
state is always the state with the lowest amount of energy
involved.
26. Reliability
Reliability is the ability of a technical device to
fulfill its function during its operation time.
This is often no longer possible if one
component has a failure. So the MTBF (Mean
time Between Failure) is often taken as a
measurement of reliability. It can either be
calculated statistically via systems in operation
or via the failure rates of the components
applied.
27. Note
The reliability does not say anything about the safety of
a system! Unreliable systems are safe if an individual
failure put the plant to the safe state each time.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37. PLC Components
The PLC mainly consists of a
CPU (Processor)
Memory areas
Input/output data devices
Separate relays
Counters
Timers
Data Storage locations
Power Supply
Programming unit
38. Processors
Processor is the brain of PLC
5 basic parts
CPU control the operation of PLC.
Memory instruction & data that tell the cpu
what to do.
Communications processor: handles
communication from outside world.
Battery :- keeps time & maintain the
programme.
Power supply: supply to run the processor.
39. Power supply
Two sources of power are used in PLC.
Battery power
Local power from plant
Battery power used to maintain the user programme /
keep the time of day, clock running, maintain the status
of certain bits and register.
40. PLC Components
Do these counters, timers, etc. really exist? No, they
don't "physically" exist but rather they are simulated
and can be considered software counters, timers, etc.
These internal relays are also simulated.
41. PLC Components
INPUT RELAYS-(contacts)
Connected to the outside world.
They physically exist and receive signals from switches,
sensors, etc.
Typically they are not relays but rather they are
transistors.
INTERNAL UTILITY RELAYS-(contacts)
Do Not Receive Signals From the Outside World nor Do
They Physically Exist.
They Are Simulated Relays and Are What Enables a PLC
to Eliminate External Relays.
42. PLC Components
COUNTERS
Do not physically exist. They are simulated counters and
they can be programmed to count pulses.
Counters can count up, down or both up and down.
Since they are simulated they are limited in their counting
speed.
Increments vary from 1ms through 1s.
43. PLC Components
TIMERS
Do not physically exist.
They come in many varieties and increments. The most
common type is an on-delay type.
Others include off-delay and both retentive and non-
retentive types.
Increments vary from 1ms through 1hr.
44. PLC Components
OUTPUT RELAYS
Connected to the outside world.
They physically exist and send on/off signals to solenoids, lights, etc.
45. PLC Components
DATA STORAGE
Typically there are registers assigned to simply store data.
They are usually used as temporary storage for math or
data manipulation.
They can also typically be used to store data when power
is removed from the PLC.
Upon power-up they will still have the same contents as
before power was removed.
Very convenient and necessary
46. Logic gates in PLC
Logic gates in a PLC are implemented in software as
compared to conventional hard-wired logic.
Any size of the logic can be implemented using same
PLC. It will not increase the size of PLC as it was the
case with conventional systems.
47. Logic gates in PLC
A
B
A
B
O
O
OA
A
B
O
(OR Gate)
(AND Gate)
(NOT Gate)
(XOR Gate)
= A . B
= A + B
= A
_
= A.B + A.B
_ _
48. Combination of Logic gates
A
A
B
B
C
C
O
Two out of three logic with digital Gates
49. Timer
On-Delay timer:-This
type of timer simply
"delays turning on".
Off-Delay timer:- This
timer simply "delays
turning off".
t
t
0
0
50. Timer
Timed:-Pulse with defined
length after signal change
from L to H at the
input.Output carries H-
signal for preset time.
Pulse:- Generate a pulse
of 1 second at the output
when input signal change
from L to H.
t
51. Flip Flop
To understand this SR
flip flop we need its
truth table which is
below,
Q
Q
SET
CLR
S
RS R Q Q
1 0 1 0
0 0 1 0
0 1 0 1
0 0 0 1
1 1 X X
52. Relays
PLC processes inputs, outputs, and the
actual program we are almost ready to
start writing a program.
But first lets see how a relay actually
works. After all, the main purpose of a
plc is to replace "real-world" relays.
We can think of a relay as an
electromagnetic switch. Apply a voltage
to the coil and a magnetic field is
generated.
53. Relays
This magnetic field attracts the contacts of the relay in,
causing them to make a connection.
These contacts can be considered to be a switch.
They allow current to flow between 2 points thereby
closing the circuit.
54. Relays
Consider example.
Here we simply turn on a bell
Whenever a switch is closed.
We have 3 real-world parts.
A switch
A relay
A bell
Whenever the switch closes we apply a current to a bell
causing it to sound.
Notice in the picture that we have 2 separate circuits.
The bottom indicates the DC part. The top indicates the
AC part.
55. PLC Operation
PLC works by continually scanning a program.
We can think of this scan cycle as
consisting of 3 most important steps.
56. PLC Operation
PLC operate very much just like a computer.
PLC read input devices, execute its program using the status of
input devices, writes the appropriate values to the output
devices.
57. Principle of Operation
Computer execute keyboard instruction while PLC follow the
program.
PLC scan time varies from mS to Seconds.
Step 1- CHECK INPUT STATUS
PLC takes a look at each input to determine if it is on or off.
Rerecords this data into its memory to be used during the next step.
58. Principle of Operation
Step 2-EXECUTE PROGRAM
PLC executes your program one instruction at a time.
It already knows which inputs are on/off from the previous
step it will be able to decide whether the program output
should be turned on based on the state of the input.
It will store the execution results for use later during the
next step.
59. Principle of Operation
Step 3-UPDATE OUTPUT STATUS
PLC updates the status of the outputs.
It updates the outputs based on which inputs were on
during the first step and the results of executing your
program during the second step.
60. PLC and other type of
controller
No. of input / output handling
Micro PLC ( Relay Replacer )
Small
Medium
Large
61. Response Time
The total response time of the PLC is a fact we have
to consider when purchasing for a PLC. Just like our
brains, the PLC takes a certain amount of time to
react to changes.
INPUT
It takes certain amount of time for the processor
to notice the input signal.
EXECUTION
Certain amount of time to process the
information received from the input.
OUTPUT
Output receives a signal from the processor
62. Processor Scan
Scan time
PLC execute only one programme and it keeps on
doing it over and over again. The time out PLC takes
to execute this programme once is called the scan
time.
Scan time can be reduced by stopping the solution
of a line of logic once it has determined it is False,
regard less of the rest of the line.
House keeping
Checking battery stakes.
Verify memory integrity.
Checking power supply.
Vesting the watchdog timer.
63. Start up Procedure
Operation Test
Place processor in “Program mode” and turn
on main power switch.
Load the pre-tested control program into the
programmable controller.
Disable all outputs, select the run mode on
the processor, and verify that the run light
on the processor is activated.
64. Start up Procedure
Check each rung of logic for proper
operation by simulating the inputs, proper
time and sequence in the program.
Make any required changes to the control
program.
Enable output modules & place processor
in “Run” mode.
Test control system as per process
operating procedure.
65. Problem sources in PLC Applications.
Field devices
Wiring
I/O modules
Program
Processor, racks, etc.
Heat protection, loose connections
Accumulation dirt, dust, failed ventilation.
Maintenance
67. Visual Inspection Perform Quarterly
Check for proper operation of ventilation system.
Check for buildup of dust or dirt.
Is any extraneous material in the cabinets.
Look for loose connections.
Are there signs of temporary modifications, jumps
etc.?
Look for signs of heating, burning, or water
infiltration.
Is all the documentation present and up to date?
Maintenance
69. Programming device
Copy the program to same secure media.
Monitor the programme which it is running.
Reload a programme from the storage media.
Make changes to the programme.