d2automation.ind2automation.in/embedded/plc report.doc · Web viewReplacing humans in tasks done in...
Transcript of d2automation.ind2automation.in/embedded/plc report.doc · Web viewReplacing humans in tasks done in...
TABLE OF CONTENTS
TOPIC
NO.
TOPIC NAMES
Chapter 1: INTRODUCTION TO THE COMPANY
1.1 OCTAL Petrochemicals
1.2 Business overview
1.3 Product application
1.4 Business Strategy
1.4.1 Operational Excellence
Chapter 2: INSTRUMENTATION
2.1 Automation
2.1.1 Advantages of automation
2.1.2 Disadvantages of automation
2.2 Engineering tools
2.2.1 PLC
2.2.2 SCADA
2.2.3 HMI
i
2.2.4 Distributed control system
2.2.5 Drives
2.3 Relay
2.3.1 Relay
2.3.2 Advantages of relay
2.3.3 Disadvantages of relay
2.4 Contactor
2.4.1 What is contactor
2.4.2 Advantages of contactor
2.4.3 Disadvantages of contactor
Chapter 3: Programmable Logic Controller
3.1 Introduction
3.2 History
3.2.1 Origin
3.2.2 Programming
3.2.3 Functionality
3.3 Architecture of PLC
3.3.1 Parts of PLC
3.3.2 PLC Pin diagram
3.4 Inputs and output of PLC ii
3.4.1 Inputs
3.4.2 Types of inputs of PLC
3.4.3 Outputs
3.4.4 Types of PLC outputs
3.5 PLC Manufactures
3.5.1 Micrologix 1000 and controller 1761
3.5.2 Features of Micrologix 1000
3.5.3 Benefits of Micrologix
3.5.4 Features expanded
3.5.5 Benefits
3.6 Program in PLC
3.6.1 Communication with PLC
3.6.2 PLC Instructions
3.6.2.1 XIC (Examine If Close)
3.6.2.2 XIO (Examine If Open)
3.6.2.3 OTE(Output Energise)
3.6.2.4 Output Latch
3.7 Times & Counter
3.7.1 Timer
3.7.1.1 Ton(Timer on)
3.7.1.2 TOFF(Timer off) iii
3.7.1.3 RTO( Retentive timer on)
3.7.2 Counter
3.7.2.1 CTU(Counter Up)
3.7.2.2 CTD(Counter Down)
3.7.2.3 EOU(Equal )
3.7.2.4 GEQ(Greater than equal to)
3.7.2.5 LEQ(Less than equal to)
3.7.2.6 GRT(Greater than)
3.7.2.7 LES(Less than)
3.7.2.8 LIM (Limit)
3.7.2.9 RES(Reset)
Chapter 4: Details on Colour Mixing Project
4.1 Objective of the project
4.2 Introduction
4.3 Features
4.4 Components required for the project
4.5 Scope of the project
4.6 Block diagram
4.7 Ladder logic for colour mixing
4.8 Hardware of the project
4.9 Working of the project iv
4.10 Different steps in mixing
Chapter 5 SCADA
5.1 Introduction
5.2 System concepts
5.3 Hardware solutions
5.4 Supervisory station
5.5 Communication infrastructure and methods
5.6 SCADA programming
5.6.1 Benefits of RSView 32
5.6.2 Programming with RSview 32
5.6.3 Graphics
5.6.4 Display screen
5.6.5 Library
5.6.6 Machines library
5.7 Conversion of a PLC program to compatible form
5.8 Modification of SCADA
5.9 Screenshots of SCADA programming
5.10 Car washing SCADA layout
Chapter 6 HMI and Drives
6.1 How to connect HMI with PLC
6.1.1 For USBv
6.1.2 For ethernet
6.1.3 After connecting
6.2. Open a new application
6.2.1 Different toolbars
6.3 Drives
6.3.1 Volts per hertz ratio
6.3.2 Catalog no. explanation
6.3.3 Drive connection
Conclusion
CHAPTER 1 - INTRODUCTION TO THE COMPANY
vi
1.1 D2 Automation
D2 Automation has emerged as one of the best Service provider in the field of Industrial Automation.
By rapidly deploying newly available technology, and building large-scale facilities,
D2 Automation is chartered to become a major contender for Industrial Automation Services.
Fig 1.1.1 Plant overview
1.2 Business Overview
Vision To be recognized as the best service provider of Automation and to become a global leader in Automation services
Mission By anticipating and exceeding our customer’s short and long-term requirements and leading the optimization of the automation services value chain, we expect to achieve strong profitability, sustained growth, and superior returns for our shareholders. Our employees will experience similarly increasing career and growth opportunities.
Values Operate within strict legal and ethical guidelines .Care about our customers and build long term relationships with them. Forge close and mutually beneficial relationships with business partners and the communities in which we operate. Attract, train, develop and retain quality employees. Continue our efforts to preserve the environment, leverage technology and improve lives of those we serve.vii
1.3 Product Applications
D2 is the fastest growing Service provider for packaging segment for liquids, foods, and consumer products
D2 has a cost effective service platform
Fig- 1.3.1 Product usage
Chapter 2: INSTRUMENTATION
2.1 Automation
Automation is the use of control systems and information technologies to reduce the need for human work in the production of goods and services. In the scope of industrialization, automation is a step beyond mechanization. Whereas mechanization provided human operators with machinery to assist them with the muscular requirements of work, automation greatly decreases the need for human sensory and mental requirements as well. Automation plays an viii
increasingly important role in the world economy and in daily experience.
Consider the examples of automation:
Automated video surveillance
Automated highway systems
Automated manufacturing
Home automation
Industrial automation
Agent-assisted Automation
2.1.1 Advantages of Automation:
Replacing human operators in tasks that involve hard physical or monotonous work. Replacing humans in tasks done in dangerous environments (i.e. fire, space, volcanoes, nuclear facilities, underwater, etc.)
Performing tasks that are beyond human capabilities of size, weight, speed, endurance, etc.
Economy improvement: Automation may improve in economy of enterprises, society or most of humanity. For example, when an enterprise invests in automation, technology recovers its investment; or when a state or country increases its income due to automation like Germany or Japan in the 20th Century.
`2.1.2 Disadvantages of Automation:
Unemployment rate increases due to machines replacing humans and putting those humans out of their jobs.
ix
Technical Limitation: Current technology is unable to automate all the desired tasks.
Security Threats/Vulnerability: An automated system may have limited level of intelligence; hence it is most likely susceptible to commit error.
Unpredictable development costs: The research and development cost of automating a process may exceed the cost saved by the automation itself.
High initial cost: The automation of a new product or plant requires a huge initial investment in comparison with the unit cost of the product, although the cost of automation is spread in many product batches of things.
2.2 ENGINEERING TOOLS
2.2.1 PLC (Programmable Logic Controller):
A programmable logic controller (PLC) or programmable controller is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or light fixtures. PLCs are used in many industries and machines. Unlike general-purpose computers, the PLC is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact.
x
HISTORY OF PLC
Origin
The PLC was invented in response to the needs of the American automotive manufacturing industry. Programmable controllers were initially adopted by the automotive industry where software revision replaced the re-wiring of hard-wired control panels when production models changed .Before the PLC, control, sequencing, and safety interlock logic for manufacturing automobiles was accomplished using hundreds or thousands of relays, cam timers, and drum sequencers and dedicated closed-loop controllers. The process for updating such facilities for the yearly model change-over was very time consuming and expensive, as the relay systems needed to be rewired by skilled electricians .In 1968 GM Hydramatic (the automatic transmission division of General Motors) issued a request for proposal for an electronic replacement for hard-wired relay systems .The winning proposal came from Bedford Associates of Bedford, Massachusetts. The first PLC, designated the 084 because it was Bedford Associates' eighty-fourth project, was the result. Bedford Associates started a new company dedicated to developing, manufacturing, selling, and servicing this new product: Modicon, which stood for Modular Digital Controller. One of the people who worked on that project was Dick Morley, who is considered to be the "father" of the PLC. The Modicon brand was sold in 1977 to Gould Electronics, and later acquired by German Company AEG and then by French Schneider Electric, the current owner .One of the very first 084 models built is now on display at Modicon's headquarters in North Andover, Massachusetts. It was presented to Modicon by GM, when the unit was retired after nearly twenty years of uninterrupted service. Modicon used the 84 moniker at the end of its product range until the 984 made its appearance.
xi
2.2.2 SCADA (Supervisory Control and Data Acquisition)
SCADA (supervisory control and data acquisition) is a category of software application program for process control, the gathering of data in real time from remote locations in order to control equipment and conditions. SCADA is used in power plants as well as in oil and gas refining, telecommunications, transportation, and water and waste control.
SCADA systems include hardware and software components. The hardware gathers and feeds data into a computer that has SCADA software installed. The computer then processes this data and presents it in a timely manner. SCADA also records and logs all events into a file stored on a hard disk or sends them to a printer. SCADA warns when conditions become hazardous by sounding alarms.
2.2.3 HMI (Human Machine Interface)
A Human-Machine Interface or HMI is the apparatus which presents process data to a human operator, and through which the human operator controls the process.
An HMI is usually linked to the SCADA system's databases and software programs, to provide trending, diagnostic data, and management information such as scheduled maintenance procedures, logistic information, detailed schematics for a particular sensor or machine, and expert-system troubleshooting guides.
The HMI system usually presents the information to the operating personnel graphically, in the form of a mimic diagram. This means that the operator can see a schematic representation of the plant being controlled.
2.2.4 Distributed Control System
A type of automated control system that is distributed throughout a machine to provide instructions to different parts of the machine.
xii
Instead of having a centrally located device controlling all machines, each section of a machine has its own computer that controls the operation. For instance, there may be one machine with a section that controls dry elements of cake frosting and another section controlling the liquid elements, but each section is individually managed by a DCS. A DCS is commonly used in manufacturing equipment and utilizes input and output protocols to control the machine
2.2.5 Drives
The main power components of an AC drive, have to be able to supply the required level of current and voltage in a form the motor can use. The controls have to be able to provide the user with necessary adjustments such as minimum and maximum speed settings, so that the drive can be adapted to the user's process.
2.3 RELAY
2.3.1 RELAY:
A relay is a simple electromechanical switch made up of an electromagnet and a set of contacts. Current flowing through the coil of the relay creates a magnetic field which attracts a lever and changes the switch contacts. It is used for double through (changeover).
Fig 2.3.1 relay
The relay's switch connections are usually labeled COM, NC and NO:
xiii
COM = Common, always connect to this, it is the moving part of the switch. NC = Normally Closed, COM is connected to this when the relay coil is off.
NO = Normally Open, COM is connected to this when the relay coil is on.
2.3.2 Advantages of relays:
Relays can switch AC and DC. Relays can switch higher voltages.
Relays are often a better choice for switching large currents (> 5A).
Relays can switch many contacts at once.
Relay can be rated for very high voltage.
2.3.3 Disadvantages of relays:
Relays are bulkier than transistors for switching small currents. Relays cannot switch rapidly (except reed relays), transistors can switch many times per second.
Relays use more power due to the current flowing through their coil.
2.4 CONTACTOR:
2.4.1 What is contactor?
Contactors are used to switch relatively large outputs and currents.
Contactors work on the same basic principle as relays.
The typical features of contactor are:
double- break ( 2 break points per contact) positive-action contacts and
xiv
closed arcing chambers (spark arresting chambers).
Fig.2.4.1 Symbol of contactor
2.4.2 Advantages of contactor:
Easy to changeover. Durable. Easy to test. Basically used for high current ratings.
2.4.3 Disadvantages of contactor:
Required more power Contacts wear
2.4.4 COMPARISON BETWEEN RELAY AND CONTACTOR:
Relay ContactorRelays possess a clapper-type armature and are characterized by single contact separation
Contactors possess a lifting armature and are characterized by double contact separation.
xv
Relays are used to switch relatively small outputs and currents.
Contactors are used to switch relatively large outputs and currents.
Table -2.4.4.1
CHAPTER -3 PLC (Programmable Logic Controller)
3.1 INTRODUCTION
Control engineering has evolved over time. In the past humans were the main methods for controlling a system. More recently electricity has been used for control and early electrical control was based on relays. These relays allow power to be switched on and off without a mechanical switch. It is common to use relays to make simple logical control decisions. The development of low cost computer has brought the most recent revolution, the Programmable Logic Controller (PLC). The advent of the PLC began in the 1970s, and has become the most common choice for manufacturing controls. PLCs have been gaining popularity on the factory floor and will probably remain predominant for some time to come. Most of this is because of the advantages they offer.
• Cost effective for controlling complex systems.
• Flexible and can be reapplied to control other systems quickly and easily.
• Computational abilities allow more sophisticated control.
• Trouble shooting aids make programming easier and reduce downtime.
xvi
• Reliable components make these likely to operate for years before failure.
The term SCADA stands for Supervisory Control and Data Acquisition. A SCADA system is a common process automation system which is used to gather data from sensors and instruments located at remote sites and to transmit and display this data at a central site for either control or monitoring purposes. Common analog signals that SCADA systems monitor and control are levels, temperatures, pressures, flow rate and motor speed. Typical digital signals to monitor and control are level switches, pressure switches, generator status, relays & motors. Automation of many different processes, such as controlling machines, basic relay control, motion control, process control is done through the use of small computers called a programmable logic controller (PLC). This is actually a control device that consists of a programmable microprocessor, and is programmed using a specialized computer language. A programmable logic controller (PLC) or programmable controller is a digital computer used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or lighting fixtures. PLC’s are used in many industries and machines, such as packaging and semiconductor machines. Unlike general-purpose computers, the PLC is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in battery-backed or non-volatile memory. A PLC is an example of a real time system since output results must be produced in response to input conditions within a bounded time, otherwise unintended operation will result.
A modern programmable logic controller is usually programmed in any one of several languages, ranging from ladder logic to Basic or C. Typically, the program is written in a development environment on a xvii
personal computer (PC), and then is downloaded onto the programmable logic controller directly through a cable connection. Programmable logic controllers contain a variable number of Input/output (I/O) ports the programmable logic controller circuitry monitors the status of multiple sensor inputs, which control output.
Fig 3.1.1 Programmable logic controller (PLC)
3.2 HISTORY
3.2.1 Origin
The PLC was invented in response to the needs of the American automotive manufacturing industry. Programmable controllers were initially adopted by the automotive industry where software revision replaced the re-wiring of hard-wired control panels when production models changed .Before the PLC, control, sequencing, and safety interlock logic for manufacturing automobiles was accomplished using hundreds or thousands of relays, cam timers, and drum sequencers and dedicated closed-loop controllers. The process for updating such facilities for the yearly model change-over was very time consuming and expensive, as the relay systems needed to be rewired by skilled electricians .In 1968 GM Hydramatic (the
xviii
automatic transmission division of General Motors) issued a request for proposal for an electronic replacement for hard-wired relay systems .The winning proposal came from Bedford Associates of Bedford, Massachusetts. The first PLC, designated the 084 because it was Bedford Associates' eighty-fourth project, was the result. Bedford Associates started a new company dedicated to developing, manufacturing, selling, and servicing this new product: Modicon, which stood for Modular Digital Controller. One of the people who worked on that project was Dick Morley, who is considered to be the "father" of the PLC. The Modicon brand was sold in 1977 to Gould Electronics, and later acquired by German Company AEG and then by French Schneider Electric, the current owner .One of the very first 084 models built is now on display at Modicon's headquarters in North Andover, Massachusetts. It was presented to Modicon by GM, when the unit was retired after nearly twenty years of uninterrupted service. Modicon used the 84 moniker at the end of its product range until the 984 made its appearance.
3.2.2 Programming
Early PLCs, up to the mid-1980s, were programmed using proprietary programming panels or special-purpose programming terminals, which often had dedicated function keys representing the various logical elements of PLC programs. Programs were stored on cassette tape cartridges. Facilities for printing and documentation were very minimal due to lack of memory capacity. The very oldest PLCs used non-volatile magnetic core memory.
xix
3.2.3 Functionality
The functionality of the PLC has evolved over the years to include sequential relay control, motion control, process control, distributed control systems and networking. The data handling, storage, processing power and communication capabilities of some modern PLCs are approximately equivalent to desktop computers. PLC-like programming combined with remote I/O hardware, allow a general-purpose desktop computer to overlap some PLCs in certain application.
3.3. ARCHITECTURE OF PLC
Fig 3.3.1 ARCHITECTURE OF PLC
3.3.1 PARTS OF PLC
POWER SUPPLY: PLC requires 24V switch mode power supply for its operation.
xx
MCU: Its full form is microcontroller unit. It is the processor of PLC. It is basically the brain of PLC. It performs various control operations of PLC.
INPUTS AND OUTPUTS: PLC has a set of isolated inputs and isolated outputs. Different PLC’s have different number and different type of inputs and outputs.Like in Micrologix 1000 we have total number of 6 inputs and 4 outputs whereas in Micrologix 1100 we have 10 inputs and 6 outputs.
MEMORY MODULE: The memory module in PLC is used for the storage of program in PLC for future use.
COMMUNICATION PORT: The communication ports are used in PLC to communicate with the computer. In PLC there are two types of communication ports i.e. RS 232 comport and Ethernet port.
This display screen is used as human machine interface i.e. it provides good visualization of operation running
3.3.2 PLC PIN DIAGRAM
xxi
Fig 3.3 .3 Pin Diagram
3.4 INPUTS AND OUTPUTS OF PLC
PLC programs are made up of a combination of the "gates" together with inputs, outputs, timers , counters, internal memory bits, analog inputs, analog outputs, mathematical calculations, comparators etc.
3.4.1 INPUTS
These are the physical connections from the real world to the PLC. They can be limit switches, push buttons, and sensors, anything that can "switch" a signal on or off. The voltages of these devices are usually, but not always, 24 Volt DC. Manufacturers make inputs that can accept a wide range of voltages both ac and dc. It should be remembered that an input can be given according to the requirements
xxii
of program which has to made for an application.
3.4.2 TYPES OF INPUTS OF PLC
USER TYPE: These are the inputs and outputs that are physically present and are practical to the inputs and outputs of the PLC.
BIT TYPE: These are the inputs and outputs that are not physically present and are functional in the PLC only. These inputs/outputs are basically used to drive each other in the ladder logic programming.
XIC (Examine if closed):
XIO (Examine if open):
Fig 3.4.2 XIC and XIO
3.4.3 OUTPUTS
These are the connections from the PLC to the real world. They are used to switch solenoids, lamps, contactors etc on and off. Again they
xxiii
I/P O/P
0 0
1 1
I/P O/P
0 1
1 0
are usually 24 Volt DC, either relay or transistor, but can also be 115/220 Volt AC.
3.4.4 TYPES OF PLC OUTPUTS
Relay type output
Transistor type output
TRIAC type output
3.5 PLC MANUFACTURES
SIEMENS
ALLEN BRADLEY
GENERAL ELECTRICAL
MITSUBISHI
SCHENIDER
ABB
Here we have done programming of two PLC’s of Allen Bradley i.e. Micrologix 1000 and Micrologix 1100.
3.5 .1 Micrologix 1000 Controllers 1761
Micrologix 1000 brings high speed, powerful instructions and flexible communications to applications that demand compact, cost-effective solutions. The Micrologix 1000 programmable controller is available in 10-point, 16-point or 32-point digital I/O versions. Analog versions are also available with 20 digital I/O points, with 4 analog inputs (two voltages and two current) and 1 analog output (configurable for either voltage or current).This little powerhouse is both inexpensive and compact, with footprints as small as 120mm x 80 mm x 40 mm (4.72"
xxiv
x 3.15" x 1.57"). The analog I/O circuitry is embedded into the base controller, not accomplished through add-on modules, providing compact and cost-effective analog performance.
3.5 .2 Features of Micrologix 1000
Preconfigured 1K programming and data memory — help ease configuration (bit, integer, timers, counters, etc) Fast processing — allows for typical throughput time of 1.5 ms for a 500-instruction program
Built-in EEPROM memory — retains all of your ladder logic and data if the controller loses power, eliminating the need for battery back-up or separate memory module
RS-232 communication channel — allows for simple connectivity to a personal computer for program upload, download and monitoring using multiple protocols, including DF1 Full Duplex
RTU slave protocol support — use DF1 Half-Duplex Slave, which allows up to 254 notes to communicate with a single master using radio modems, leased-line modems or satellite uplinks
The Micrologix 1000 family provides small, economical programmable controllers. They are available in configurations of 10 digital I/O (6 inputs and 4 outputs), 16 digital I/O (10 inputs and 6 outputs), 25 I/O (12 digital inputs, 4 analog inputs, 8 digital outputs, and 1 analog output), or 32 digital I/O (20 inputs and 12 outputs) in multiple electrical configurations of digital I/O. The I/O options and electrical configurations make them ideal for many applications.
xxv
Fig 3.5.2 Micrologix 1000
3.5.3 Benefits of Micrologix
Compact design—Lets the MicroLogix 1000 controller thrive in limited panel space.
Choice of communication networks—An RS-232-C communication port is configurable for: DF1 protocol for direct connection to a programming device or operator interface; DH-485 networking through a 1761-NET-AIC converter; Device Net networking through a 1761-NET-DNI interface; Ethernet/IP networking through a 1761-NET-ENI interface; or for half-duplex slave protocol in SCADA applications.
Simple programming with your choice of programming device—You can program these controllers in familiar ladder logic with MicroLogix 1000 A.I. Series Software®, PLC 500 A. I. Series Programming Software, RSLogix 500™ Windows Programming Software, or the MicroLogix Hand-Held Programmer (1761-HHP-B30). This symbolic programming language is based on relay ladder wiring diagrams that simplify the creation and troubleshooting of your control program.
xxvi
Comprehensive instruction set—Over 65 instructions including simple bit, timer, and counter instructions, as well as instructions for powerful applications like sequencers, high-speed counter, and shift registers.
Fast—Execution time for a typical 500-instruction program is only 1.56 ms.
Choice of languages—Software and documentation are available in 5 languages. Thehand-held programmer has 6 languages built in.
3.5.4 Features
The MicroLogix 1100 has 10 digital inputs, 2 analog inputs and 6 digital outputs, and supports expansion I/O. Up to four 1762 I/O modules (also used on the MicroLogix 1200) may be added to the embedded I/O, providing application flexibility and support of up to 80 digital I/O.
One embedded 20 kHz high-speed counter (on controllers with DC inputs)—The built-in independent high-speed counter uses 32-bit integers for extended range, features 8 modes of operation, and supports direct control of outputs independent of program scan.
Two 20 kHz high-speed PTO/PWM outputs (on controllers with DC outputs).
Digital trim potentiometers—Allow quick and easy adjustments of timers, counters, set points, and more.
Program data security—Data file download protection lets a program be reloaded into the controller without overwriting protected data.
xxvii
Floating Point Data Files—You can create data files that can contain up to 256 IEEE-754 floating point values.
Memory modules—Memory backup provides protection and transportability for programs and data.
Four interrupt inputs—Interrupt inputs let the controller scan a specific program file (subroutine) when an input condition is detected from a sensor or field device.
Real-Time Clock—embedded in every controller.
Fig 3.5.4 Micrologix 1100 with Analog Card
3.5.5 Benefits
Online Editing—modifications can be made to a program while it is running, making fine tuning of an operating control system possible, including PID loops. Not only does this feature reduce development time, but it aids in troubleshooting. Built-in LCD—lets you monitor data within the controller, optionally modify that data and interact with the control program.
xxviii
The LCD displays status for embedded digital I/O and controller functions, and acts as a pair of digital trim pots to allow a user to tweak and tune a program.
Ethernet/IP Port—for peer-to-peer messaging offers users high-speed connectivity between controllers and the ability to access, monitor and program from the factory floor to anywhere an Ethernet connection is available.
Isolated RS-232/RS-485 combo port—provides a host of different point-to-point and network protocols.
Embedded Web Server—lets you custom configure data from the controller to be displayed as a web page.
3.6 PROGRAMMING IN PLC
PLC programs are written in a special application on a personal computer, then downloaded by a direct-connection cable or over a network to the PLC. The program is stored in the PLC either in battery-backed-up RAM or some other non-volatile flash memory. Often, a single PLC can be programmed to replace thousands of relays. Under the IEC 61131-3 standard, PLCs can be programmed using standards-based programming languages. A graphical programming notation called Sequential Function Charts is available on certain programmable controllers. Recently, the International standard IEC 61131-3 has become popular. IEC 61131-3 currently defines five programming languages for programmable control systems: FBD (Function block diagram), LD (Ladder diagram), ST (Structured text, similar to the Pascal programming language), IL (Instruction list, similar to assembly language) and SFC (Sequential function chart). These techniques emphasize logical organization of operations .While the fundamental concepts of PLC programming are common to all manufacturers, differences in I/O addressing, memory organization and instruction sets mean that PLC programs are never perfectly
xxix
interchangeable between different makers. Even within the same product line of a single manufacturer, different models may not be directly compatible.
In Allen Bradley PLC’s the logic used for the programming is ladder logic. Ladder logic is a programming language that represents a program by a graphical diagram based on the circuit diagrams of relay-based logic hardware. It is primarily used to develop software for Programmable Logic Controllers (PLCs) used in industrial control applications. 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. An argument that aided the initial adoption of ladder logic was that a wide variety of engineers and technicians would be able to understand and use it without much additional training, because of the resemblance to familiar hardware systems. This argument has become less relevant given that most ladder logic programmers have a software background in more conventional programming languages, and in practice implementations of ladder logic have characteristics—such as sequential execution and support for control flow features—that make the analogy to hardware somewhat imprecise .Ladder logic is widely used to program PLCs, where sequential control of a process or manufacturing operation is required. Ladder logic is useful for simple but critical control systems, or for reworking old hardwired relay circuits. As programmable logic controllers became more sophisticated it has also been used in very complex automation systems.
xxx
Fig 3.6.1 Simple ladder logic
The language itself can be seen as a set of connections between logical checkers (contacts) and actuators (coils). If a path can be traced between the left side of the rung and the output, through asserted (true or "closed") contacts, the rung is true and the output coil storage bit is asserted (1) or true. If no path can be traced, then the output is false (0) and the "coil" by analogy to electromechanical relays is considered "de-energized". The analogy between logical propositions and relay contact status is due to Claude Shannon.Ladder logic has contacts that make or break circuits to control coils. Each coil or contact corresponds to the status of a single bit in the programmable controller's memory. Unlike electromechanical relays, a ladder program can refer any number of times to the status of a single bit, equivalent to a relay with an indefinitely large number of contacts.So-called "contacts" may refer to physical ("hard") inputs to the programmable controller from physical devices such as pushbuttons and limit switches via an integrated or external input module, or may represent the status of internal storage bits which may be generated elsewhere in the program.Each rung of ladder language typically has one coil at the far right. Some manufacturers may allow more than one output coil on a rung.--( )-- a regular coil, energized whenever its rung is closed--(\)-- a "not" coil, energized whenever its rung is open--[ ]-- A regular contact, closed whenever its corresponding coil is energized--[\]-- A "not" contact, open whenever its corresponding coil is energized
xxxi
The "coil" (output of a rung) may represent a physical output which operates some device connected to the programmable controller, or may represent an internal storage bit for use elsewhere in the program.
Fig 3.6.2 PLC Trainer Kit
The above figure shows the view of PLC trainer kit. On this kit various operations are performed. It has following components mounted:
1 .PLC MicroLogix1000 2 .SMPS (220V AC-24V DC)
3. A Contactor Relay 4. An Electromechanical Relay
5. Normally open Switch (4) 6. Normally closed Switch (4)
7. Output LED’s (4) 8. RS 232 Comport for communication with PC
3.6.1 COMMUNICATION OF PLC WITH PC
To make communication of PLC with PC following steps are noted down:
xxxii
Connect PC and PLC via RS232 comport or Ethernet.
Then click on RS Linx icon, a window will appear as shown in fig below
Fig 3.6.3 RS Linx classic window
In this window add drivers i.e. whether it is RS232 comport or Ethernet and configure the drivers and closes the window
Then click on icon RS who on the RS Linx classic window, another window will appear as shown in fig After opening the RS who window click on AB DF1-1 DH-485, the PLC is running is shown on the window. Then close this window and double click on RS Logix 500 starter.
3.6.2 PLC INSTRUCTIONS
There are various instructions which are useful for making ladder logic for PLC programming. These are as follows:
3.6.2.1 XIC (Examine if closed):
xxxiii
Use the XIC instruction in your ladder program to determine if a bit is ON. When the instruction is executed, if the bit addressed is on (1), then the instruction is evaluated as true. When the instruction is executed, if the bit addressed is off (0), then the instruction is evaluated as false.
XIC (Examine if closed):
Fig 3.6.4 XIC
A push button wired to an input (addressed as I:0/4). An output wired to a pilot light (addressed as O:0/2). A timer controlling a light (addressed as T4:3/DN).
3.6.2.2 XIO (Examine if open):
Use the XIO instruction in your ladder program to determine if a bit is OFF. When the instruction is executed, if the bit addressed is off (0), then the instruction is evaluated as true. When the instruction is executed, if the bit addressed is on (1), then the instruction is evaluated as false.
Fig 3.6.5 XIO
Examples of devices that turn on or off include:
• Motor overload normally closed (N.C.) wired to an input (I:0/10).xxxiv
I/P O/P
0 0
1 1
I/P O/P
0 1
1 0
• An output wired to a pilot light (addressed as O:0/4).
• A timer controlling a light (addressed as T4:3/DN)
3.6.2.3 Output Energize (OTE):
Use the OTE instruction in your ladder program to turn on a bit when rung conditions are evaluated as true. An example of a device that turns on or off is an output wired to a pilot light (addressed as O:0/4).
Fig 3.6.6 OTE
3.6.2.4 Output Latch (OTL) and Output Unlatch (OTU):
OTL and OTU are retentive output instructions. OTL can only turn on a bit, while OTU can only turn off a bit. These instructions are usually used in pairs, with both instructions addressing the same bit. Your program can examine a bit controlled by OTL and OTU instructions as often as necessary.
Fig 3.6.7 Latch output and Unlatch output
3.7. TIMERS AND COUNTERS
3.7.1 TIMER
Timers are used to perform the timing operations. Time base is the minimum value of time in second that can be taken by the timer. xxxv
Preset value is the total number of the seconds for which the timing operation has to be done Accumulator starts increasing the time in seconds upto the preset value. Upto the preset value of the accumulator the enable bit of timer is high & the timer runs. When accumulator reaches the preset value then the timer stops and the done bit of the timer becomes high.
The timer has following bits and these bits are useful in the operation of timer:
EN- Enable- This bit will high when the input is given to the timer
TT - Timer timing bit - This bit will be high during the timing process. It remains high till accumulator value becomes equal to preset value
DN – Done – This bit will be high when the timing process is ended. It set to high when the accumulator value becomes equal to preset value.
In Micrologix 1000 and 1100 PLC there are three types of timers i.e. TON Timer
T-OFF Timer
Retentive timer ON (RTO)
3.7.1.1 TON Timer :Use the TON instruction to turn an output on or off after the timer has been on for a preset time interval. The TON instruction begins to count time-base intervals when rung conditions become true. As long as rung conditions remain true, the timer adjusts its accumulated value (ACC) each evaluation until it reaches the preset value (PRE). The accumulated value is reset when rung conditions go false, regardless of whether the timer has timed out
xxxvi
Fig 3.7.1 TON timer
3.7.1.2 T-OFF Timer :Use the TOF instruction to turn an output on or off after its rung has been off for a preset time interval. The TOF instruction begins to count time base intervals when the rung makes a true-to-false transition. As long as rung conditions remain false, the timer increments its accumulated value (ACC) based on the time base for each scan until it reaches the preset value (PRE). The accumulated value is reset when rung conditions go true regardless of whether the timer has timed out.
Fig 3.7.2 T-OFF timer
3.7.1.3 Retentive Timer (RTO):Use the RTO instruction to turn an output on or off after its timer has been on for a preset time interval. The RTO instruction is a retentive instruction that begins to count time base intervals when rung conditions become true.The RTO instruction retains its accumulated value when any of the following occurs:
xxxvii
Fig 3.7.3 Retentive Timer (RTO)
3.7.2 Counters:
Counters are used to count the number of operations. Its function is same as the timer accepts that the timer counts the number of seconds and the counter counts the number of operations or pulses. At each operation the value of the accumulator increases and when the value of the accumulator comes to the preset value of the counter then the counter stops.
Counter bits:
TT - Timer timing bit - This bit will be high during the counting process. It remains high till accumulator value becomes equal to preset value
DN – Done – This bit will be high when the counting process is ended. It set to high when the accumulator value becomes equal to preset value.
3.7.2 Counter
3.7.2.1 Counter UP (CTU):The CTU is an instruction that counts false-to-true rung transitions. Rung transitions can be caused by events occurring in the program (from internal logic or by external field devices) such as parts travelling past a detector or actuating a limit switch. When rung conditions for a CTU instruction have made a false-to-true transition, the accumulated value is incremented by one
xxxviii
count, provided that the rung containing the CTU instruction is evaluated between these transitions. The ability of the counter to detect false-to-true transitions depends on the speed (frequency) of the incoming signal. The accumulated value is retained when the rung conditions again become false. The accumulated count is retained until cleared by a reset (RES) instruction that has the same address as the counter reset.
Fig 3.7.4 Counter UP (CTU)
3.7.2.2 Counter Down (CTD): The CTD is an instruction that counts false-to-true rung transitions. Rung transitions can be caused by events occurring in the program such as parts traveling past a detector or actuating a limit switch. When rung conditions for a CTD instruction have made a false-to-true transition, the accumulated value is decremented by one count, provided that the rung containing the CTD instruction is evaluated between these transitions. The accumulated counts are retained when the rung conditions again become false. The accumulated count is retained until cleared by a reset (RES) instruction that has the same address as the counter reset.
Fig 3.7.5 Counter Down (CTD)
xxxix
3.7.2.3 EQU (equal to)
Fig 3.7.6 Equal to
This input instruction is true when source A becomes equal to source B. The EQU instruction compares two user specified values if values are equal, it allows rung continuity. The rung goes true and output energies.
3.7.2.4 GEQ (greater than equal to)
This instruction compares two values and will be high when the counted value becomes equal to or greater than the fixed value and will energize everything that is connected next to it.
Fig 3.7.7 Greater than Equal to
3.7.2.5 LEQ(less than equal to)
Fig 3.7.8 Less than Equal to
xl
This instruction compares two values and will be high when the counted value becomes equal to or less than the fixed value and will energize everything that is connected next to it.
3.7.2.6 GRT (greater than)
Fig 3.7.9Greater Than
Use of the GRT instruction to test whether one value (source A) is greater than another (source B). If the value at source A is greater than the value at source B, the instruction is logically true. If the value at source A is less than or equal to the value at source B, the instruction is logically false. Source A must be an address. Source B can either be a program constant or an address. Negative integers are stored in two’s complement form.
3.7.2.7 LES (less than)
Use of the LES instruction is to test whether one value (source A) is less than another (source B). If source A is less than the value at source B, the instruction is logically true. If the value at source A is greater than or equal to the value at source B, the instruction is logically false. Source A must be an address. Source B can either be a program constant or an address. Negative integers are stored in two’s complement form.
xli
Fig 3.7.10 Less than
3.7.2.8 LIM (Limit):
Fig 3.7.11 Limit
Use the LIM instruction to test for values within or outside a specified range, depending on how you set the limits.
3.7.2.9 RES (Reset):
Fig 3.2.1 Reset
Use a RES instruction to reset a timer or counter. When the RES instruction is enabled, it resets the Timer ON Delay (TON), Retentive Timer (RTO), Count UP (CTU), or Count Down (CTD) instruction having the same address as the RES instruction .When resetting a counter, if the RES instruction is enabled and the counter rung is enabled, the CU or CD bit is reset. If the counter preset value is negative, the RES instruction sets the accumulated value to zero. This in turn causes the done bit to be set by a count down or count up instant.
xlii
CHAPTER 4- DETAILS ON COLOUR MIXING SYSTEM
4.1 OBJECTIVE OF THE PROJECT
The aim of this project is to design a Plc (Programming Logic Controller) based Color mixing system that sense the presence of bucket and level of color in it and then fills it accordingly up to a fixed level. In this project we developed proximity sensor using infrared sensor that detects the presence of bucket.
Here we use Plc to control for the filling of color in the bucket. Plc provides the sample input to the computer and with these Ladder Logic program generates control signal for solenoid tap and that can be accessed by it through Plc.
The colour mixing system is an automated System. Here the objective is to take out three different colours in a sequence, and for this purposes PLC (Programmable Logic Controller) has been implemented. Here when we will press switch A the empty bucket which is placed on the rotating conveyor belt starts moving with Belt. As soon as the bucket comes in front of position Sensor under red colour tank, a signal goes to plc, resulting opens the valve. After some delay (mentioned in the program) valve closes. The conveyer belt starts again. This process provides red colour to us, If we will press switch number B the empty bucket which is placed on the rotating conveyor belt starts moving with belt. As soon as the bucket comes in front of position Sensor under yellow colour tank a signal goes to plc, resulting opens the valve. After some delay (mentioned in the program) valve closes. The conveyer belt starts again. This process provides yellow colour to us, during this process the bucket passes through red tank also but it will not stop there because of the programming, and if we will press switch C the bucket will stop in front of both the tanks and get filled with 50% red and 50% yellow so that we can get orange color.
4.2 INRODUCTION
Simplification of engineering and precise control of manufacturing process can result in significant cost savings. The most cost-effective xliii
way, which can pay big dividend in the long run, is flexible automation; a planned approach towards integrated control systems. It requires a conscious effort on the part of plant managers to identify areas where automation can result in better deployment/utilization of human resources and savings in man-hours, down time. Automation need not be high ended and too sophisticated; it is the phased, step-by-step effort to automate, employing control systems tailored to one’s specific requirements that achieves the most attractive results. That is where Industrial electronics has been a breakthrough in the field of automation and control techniques.
The aim of this project is to design a Plc (Programming Logic Controller) based Colour mixing system that sense the presence of bottle and level of colour in it and then fills it accordingly up to a fixed level. In this project we developed proximity sensor using infrared sensor that detects the presence of bottle.
Here we use Plc to control for the filling of colour in the bottles. Plc provides the sample input to the computer and with these Ladder Logic program generates control signal for solenoid tap and that can be accessed by it through Plc.
4.3 FEATURES:
It’s very efficient Low cost Easy to build Reduce human efforts. Working is very fast. Performing tasks that are beyond human capabilities of size, weight, speed) Reliability and maintainability. Flexibility
4.4 Components required for the project
xliv
Elements used for project
Programmable logic controller (Allen Bradley) Switch mode power supply (24v dc) IR sensor reflector Power supply 12v Momentary switches Gear motor for conveyer belt (12v) A solenoid valve (12v) Indicator (24v) Relay
4.5 Scope of the project on Colour Mixing System
A project based on the process used in paint industries to create different colors.
As per our industrial and online survey different color are created by basic three color.
We are presenting a project based on the same process in which we are creating orange by mixing Red and Yellow.
4.6 Block Diagram
xlv
Fig 4.6.1 Block diagram of project
4.7 Ladder Logic for the Colour Mixing System
Fig 4.7.1 Ladder logic showing inputs and binary inputs
xlvi
Fig 4.7.2 Ladder logic showing timers
Fig 4.7.3 Ladder logic showing binary inputs and timers
xlvii
Fig 4.7.4 Ladder logic showing binary inputs with timer bits
Fig 4.7.5 Ladder logic showing two timers which will start after one another
xlviii
Fig 4.7.6 Ladder logic showing the end of the program
4.8 Hardware of the Project
Fig 4.8.1 Project hardware
xlix
4.9 Working of the projectThe project works by pressing buttons which are acting as inputs to the PLC and as outputs the lights glow respectively according to the button pressed
Fig 4.9.1 Red button is pressed i.e. red colour selected
l
Fig 4.9.2 Yellow button is pressed i.e yellow colour is selected
Fig 4.9.3 Mixing of colours
4.10 Different steps in mixing of colours By pressing ‘A’ push button, the process will start and we will get
red color. The star button also activates the PLC (Programmable Logic
Controller).The PLC will generate a signal to drive the conveyer
li
belt. The conveyer belt starts moving and the bucket comes under a proper position.
The sensor (intruder) senses the position of the bucket and generates an appropriate signal. This signal is applied to the PLC.
After receiving the signal PLC (Programmable logic controller) respond according to the program stored.
PLC generates a signal such that it will drive the valve 1. The pump motor will start filling the bucket with red color. After certain time delay valve will close. This time delay (already mentioned in the program) is equal to the
time taken to fill a bucket. After this time delay PLC (Programmable Logic controller)
generate a signal to drive the conveyer belt. The next switch B will run the conveyer as well but this time the
bucket will stop only in under the yellow tank. Again the sensor (intruder) senses the position of the bucket and
generates an appropriate signal. Again the PLC (programmable logic controller) starts filling the
yellow c If we will press switch C the bucket will stop in front of both the tanks and get filled with 50% red and 50% yellow so that we can get orange color.
CHAPTER 5 - SCADA
5.1 Introduction
SCADA stands for Supervisory Control And Data Acquisition. It
generally refers to an industrial control system: a computer system
monitoring and controlling a process. The process can be industrial,
infrastructure or facility based as described below:
lii
Industrial processes include those of manufacturing, production,
power generation, fabrication, and refining, and may run in
continuous, batch, repetitive, or discrete modes.
Infrastructure processes may be public or private, and include
water treatment and distribution, wastewater collection and
treatment, oil and gas pipelines, electrical power transmission
and distribution, civil defence siren systems, and large
communication systems.
Facility processes occur both in public facilities and private
ones, including buildings, airports, ships, and space stations.
They monitor and control HVAC, access, and energy
consumption.
A SCADA System usually consists of the following subsystems:
A Human-Machine Interface or HMI is the apparatus which
presents process data to a human operator, and through this, the
human operator monitors and controls the process.
A supervisory (computer) system, gathering (acquiring) data on
the process and sending commands (control) to the process.
Remote Terminal Units (RTUs) connecting to sensors in the
process, converting sensor signals to digital data and sending
digital data to the supervisory system.
liii
Programmable Logic Controller (PLCs) used as field devices
because they are more economical, versatile, flexible, and
configurable than special-purpose RTUs.
Communication infrastructure connecting the supervisory
system to the Remote Terminal Units
There is, in several industries, considerable confusion over the
differences between SCADA systems and Distributed control systems
(DCS). Generally speaking, a SCADA system usually refers to a
system that coordinates, but does not control processes in real time.
The discussion on real-time control is muddied somewhat by newer
telecommunications technology, enabling reliable, low latency, high
speed communications over wide areas. Most differences between
SCADA and DCS are culturally determined and can usually be
ignored. As communication infrastructures with higher capacity
become available, the difference between SCADA and DCS will fade
5.2 Systems concepts
The term SCADA usually refers to centralized systems which monitor
and control entire sites, or complexes of systems spread out over large
areas (anything between an industrial plant and a country). Most
control actions are performed automatically by remote terminal units
("RTUs") or by programmable logic controllers ("PLCs"). Host
control functions are usually restricted to basic overriding or
supervisory level intervention. For example, a PLC may control the liv
flow of cooling water through part of an industrial process, but the
SCADA system may allow operators to change the set points for the
flow,and enable alarm conditions, such as loss of flow and high
temperature, to be displayed and recorded. The feedback control loop
passes through the RTU or PLC, while the SCADA system monitors
the overall performance of the loop.
Fig 5.2.1 SCADA SYSTEM
5.3 Hardware solutions
SCADA solutions often have Distributed Control System (DCS)
components. Use of "smart" RTUs or PLC’s, which are capable of
autonomously executing simple logic processes without involving the
master computer, is increasing. A functional block programming
language, IEC 61131-3 (Ladder Logic), is frequently used to create
programs which run on these RTUs and PLC’s. Unlike a procedural
lv
language such as the C programming language or FORTRAN, IEC
61131-3 has minimal training requirements by virtue of resembling
historic physical control arrays. This allows SCADA system engineers
to perform both the design and implementation of a program to be
executed on an RTU or PLC. A Programmable automation controller
(PAC) is a compact controller that combines the features and
capabilities of a PC-based control system with that of a typical PLC.
PACs are deployed in SCADA systems to provide RTU and PLC
functions. In many electrical substation SCADA applications,
"distributed RTUs" use information processors or station computers to
communicate with protective relays, PACS, and other devices for I/O,
and communicate with the SCADA master in lieu of a traditional
RTU.
Since about 1998, virtually all major PLC manufacturers have offered
integrated HMI/SCADA systems, many of them using open and non-
proprietary communications protocols. Numerous specialized third-
party HMI/SCADA packages, offering built-in compatibility with
most major PLC’s, have also entered the market, allowing mechanical
engineers, electrical engineers and technicians to configure HMI’s
themselves, without the need for a custom-made program written by a
software developer.
lvi
5.4 Supervisory Station
The term "Supervisory Station" refers to the servers and software
responsible for communicating with the field equipment (RTUs,
PLC’s, etc), and then to the HMI software running on workstations in
the control room, or elsewhere. In smaller SCADA systems, the
master station may be composed of a single PC. In larger SCADA
systems, the master station may include multiple servers, distributed
software applications, and disaster recovery sites. To increase the
integrity of the system the multiple servers will often be configured in
a dual-redundant or hot-standby formation providing continuous
control and monitoring in the event of a server failure.
Initially, more "open" platforms such as Linux were not as widely
used due to the highly dynamic development environment and
because a SCADA customer that was able to afford the field hardware
and devices to be controlled could usually also purchase UNIX or
OpenVMS licenses. Today, all major operating systems are used for
both master station servers and HMI workstations.
5.5 Communication infrastructure and methods
SCADA systems have traditionally used combinations of radio and
direct serial or modem connections to meet communication
requirements, although Ethernet and IP over SONET / SDH is also
frequently used at large sites such as railways and power stations. The
lvii
remote management or monitoring function of a SCADA system is
often referred to as telemetry.
This has also come under threat with some customers wanting
SCADA data to travel over their pre-established corporate networks or
to share the network with other applications. The legacy of the early
low-bandwidth protocols remains, though. SCADA protocols are
designed to be very compact and many are designed to send
information to the master station only when the master station polls
the RTU. Typical legacy SCADA protocols include Modbus RTU,
RP-570, Profibus and Conitel. These communication protocols are all
SCADA-vendor specific but are widely adopted and used. Standard
protocols are IEC 60870-5-101 or 104, IEC 61850 and DNP3. These
communication protocols are standardized and recognized by all
major SCADA vendors. Many of these protocols now contain
extensions to operate over TCP/IP. It is good security engineering
practice to avoid connecting SCADA systems to the Internet so the
attack surface is reduced.
RTUs and other automatic controller devices were being developed
before the advent of industry wide standards for interoperability. The
result is that developers and their management created a multitude of
control protocols. Among the larger vendors, there was also the
incentive to create their own protocol to "lock in" their customer base.
A list of automation protocols is being compiled here.
lviii
Recently, OLE for Process Control (OPC) has become a widely
accepted solution for intercommunicating different hardware and
software, allowing communication even between devices originally
not intended to be part of an industrial network.
5.6 SCADA Programming
The SCADA system used by us is SCADA RSVIEW32. This SCADA
system is created by Rockwell Automation. It has variety of
commands, tool library and many other features required for
programming. RSView®32™ is an integrated, component-based HMI
for monitoring and controlling automation machines and processes.
RSView32 is available in English, Chinese, French, German, Italian,
Japanese, Portuguese, Korean, and Spanish. RSView32 expands your
view with open technologies that provide unprecedented connectivity
to other Rockwell Software products, Microsoft products, and third-
party applications
RSView32 was the first HMI software to:
Open its graphic displays as OLE containers for ActiveX®
controls — with thousands of third-party ActiveX controls to
choose from, you can drop ready-made solutions right into your
projects
Develop an object model to expose portions of its core
functionality, allowing RSView32 to interoperate easily with
other component-based software products
lix
Integrate Microsoft's popular Visual Basic® for Applications
(VBA) as a built-in programming language allowing almost
unlimited ways to customize your RSView32 projects
Support OPC standards as both a server and a client for fast,
reliable communications with a wide variety of hardware
devices
Implement add-on architecture (AOA) technology to expand
RSView32's functionality and integrate new features directly
into RSView32's core
5.6.1 Benefits of RSVIEW32
Interact with other Rockwell Software products
Share data with Microsoft products
Enjoy preferred compatibility with Rockwell Automation
products
Maximize your hardware investments with OPC
Update projects online
5.6.2 Programming with RSVIEW32
lx
Double click on RSVIEW32 icon and a window will appear named
‘RSVIEW32 show works’.
Whenever the RSVIEW software is opened for the SCADA system
then a following window will appear. At the right most corner of this
software the project window will appear. In this window there are all
the options related to our project in the SCADA. Like system,
graphics, alarms, datalogs, logic & control etc.
Fig- 5.6.2.1 RS View 32 page
These all the options are used in this window are the important options
that are needed in the SCADA operation. Double clicking on each of lxi
the option will again open the list of sub options under that category.
Clicking on
the new button on the left corner will start a new project.
After clicking on new button we have to first save the file. Then click
on graphics & then click on display. A display screen will appear.
This screen is used to make the SCADA constructions.
5.6.3 GRAPHICS:
Fig 5.6.3.1 Graphics window
5.6.4 DISPLAY SCREEN:
lxii
Fig- 5.6.4.1 New project display screen
5.6.5 LIBRARY:
The library under the graphic window consists of different type of
tools for the SCADA system. These tools consists of almost all the
tools & machines that are being used in the industry. These tools can
be placed on the display screen. To place these tools on the display
screen we need to just copy the tolls from the library & then use the
paste option to place the tools on the display screen.
The figure below shows the library which contains the different type
of bottles. These bottles can be used in the SCADA system to show
the bottle filling process in the SCADA system.
5.6.6 BOTTLES LIBRARY:
lxiii
Fig- 5.6.6.1 Bottle selection
5.6.7 MACHINES LIBRARY:
lxiv
Fig 5.6.7.1 Machine library
5.7 CONVERSION OF A PLC PROGRAM INTO SCADA COMPATIBLE FORM
A Program that is made in the PLC can be used by the SCADA
system. That program can be controlled from the SCADA system
directly without pressing any switch. Some modification is necessary
to make the program compatible to SCADA. For the program to be
used through SCADA it is necessary that each bit & switch should be
companied by another bit. That bit is called SCADA bit. SCADA bit
is inserted in parallel with the parallel bit & is inserted in series with
the series bit.
Then the tagging process is done in SCADA. In tagging process the
address of each SCADA bit is given to the particular switch in
SACDA. Means that the start button in SCADA will be given the tag
name of the start SCADA bit in the input rung of the original program
lxv
5.8 MODIFICATION FOR SCADA:
Fig 5.8.1 Use of binary bits for SCADA
In this the start bit B3:0/1 is tagged to the start button in the SCADA
display & stop bit B3:0/1 is tagged to the stop button in the SCADA
lxvi
display. Using those start & stop buttons the program can be
controlled directly from the scada screen without actually pressing the
buttons. In this way to control each operation the corresponding scada
bit must be inserted in the PLC program so that sacda can
communicate with the PLC program.
5.9 Screenshots of SCADA programming
Fig 5.9.1 Creating of digital tags
lxvii
Fig 5.9.2 Creating a button
5.10 Car washing SCADA layout
lxviii
Fig 5.10.1 Car enters the washing area
Fig 5.10.2 Car entered
lxix
Fig 5.10.3 Car is being washed by water spray
Fig 5.10.4 Car has been washed
lxx
Fig 5.10.5 Car leaves the washing area
lxxi
CHAPTER -6 HMI (HUMAN MACHINE INTERFACE) and
Drives
The user interface (also known as human computer interface or man-
machine interface (MMI)) is the aggregate of means by which people
—the users—interact with the system—a particular machine, device,
computer program or other complex tool. The user interface provides
means of:
• Input, allowing the users to manipulate a system
• Output, allowing the system to indicate the effects of the users'
manipulation.
• The design of a user interface affects the amount of effort the
user must expend to provide input for the system and to interpret the
output of the system, and how much effort it takes to learn how to do
this. Usability is the degree to which the design of a particular user
interface takes into account the human psychology and physiology of
the users, and makes the process of using the system effective,
efficient and satisfying.
lxxii
6.1 How to connect HMI with PC
The terminal of HMI can be connected with PC either by USB or
Ethernet port. You must have to enter the panel address of your HMI
in your browser (Internet Explore, mozila firebox etc.). You can also
transfer programme by pen drive.
6.1.1 For USB
The panel view component have a USB port to support
communication with USB. You must first install ALLEN BRADLEY
Panel view USB remote NDIS network device driver on your
computer. The default address of Allen Bradley HMI is
169.254.2542.
6.1.2 For Ethernet
For Ethernet first install the drivers. The default address of single
Allen Bradley HMI is 169.254.2542. If you install more than one
HMI in the circuit then the address start from 169.254.0.0 to
169.254.255.255.
6.1.3 After connecting
After connecting the HMI with PC. Fill the default IP address in the
web browser software. Then panel view component is shown as
shown in fig.
lxxiii
Fig 6.1.3.1 Panel view component screen
Fig 6.1.3.2 HMI program screen
6.2OPEN A NEW APPLICATION
lxxiv
Applications are created with default file names that you can change when saving the application. The default file name is PVcApplication1. The number automatically increments as you create new applications.
Click the Create & Edit button in the Panel View Explorer Start up window
Review areas of screen. This is where you will spend most of your time
6.2.1 Different toolbars
Navigation tabs Provides access to the different functional areas of an application
Application toolbar Provides common tools that are available to all views of the application. Drag your mouse over each tool
Cursor controls Hides or shows the Controls or Properties panel to increase the workspace area
Screen list Contains a list of screens in the application including the alarm banner and diagnostics banner
Screen workspace Contains objects that you drag to the screen from the object palette
6 Object palette Contains panels of objects that you can drag to the screen workspace. Click the cursor on a tab to open or close a panel of objects. The palette can occupy 25, 50 or 75% of the Controls panel. Right-click on the object palette heading to resize it. The object palette and screen list are resized accordingly
7 Screen toolbar Contains tools that operate on selected objects in the screen workspace. Also contains a tool for turning the screen grid on or off.
lxxv
Fig 6.2.1.1 Toggles designed in HMI
lxxvi
Fig 6.2.1.2 HMI screen designing
6.3 DRIVESA variable-frequency drive (VFD) is a system for controlling the rotational speed of an alternating current electric motor by controlling the frequency of the electrical power supplied to the motor. A variable frequency drive is a specific type of adjustable-speed drive. Variable-frequency drives are also known as adjustable-frequency drives (AFD), variable-speed drives (V SD), AC drives, micro drives or inverter drives. Since the voltage is varied along with frequency, these are sometimes also called VVVF (variable voltage variable frequency) drives .Variable-frequency drives are widely used. For example, in ventilations systems for large buildings, variable-frequency motors on fans save energy by allowing the volume of air moved to match the system demand. Variable frequency drives are also used on pumps, conveyor and machine tool drives.
Fig 6.3.1 Drives
6.3.1 Volts per Hertz (v/f) Ratio
Flux should remain constant in order to produce full load torque which is achieved by maintaining a constant magnetic flux in the motor. This method of magnetic flux control is called the volts-per-hertz ratio. With this method, the frequency and voltage must increase in the same proportion to maintain good torque production at the motor. For example, if the frequency is 60 Hz
lxxvii
and the voltage is 460 V, then the volts per Hertz ratio(460 divided by 60) would be 7.6 V/Hz. So, at half speed on a 460 V supplied system, the frequency would be 30 Hertz and the voltage applied to the motor would be 230 V and the ratio would still be maintained at 7.6 V/Hz. This ratio pattern saves energy going to the motor, but it is also very critical to performance. The variable-frequency drive tries to maintain this ratio because if the ratio increases or decreases as motor speed changes, motor current can become unstable and torque can diminish. On the other hand, excessive current could damage or destroy the motor. In a PWM drive the voltage change required to maintain a constant Volts-per-Hertz ratio as the frequency is changed is controlled by increasing or decreasing the widths of the pulses created by the inverter. And, a PWM drive can develop rated torque in the range of about 0.5 Hz and up. amperage rating of the drive (All motors will operate at the same frequency). This can be an advantage because all of the motors will change speed together and the control will be greater.
lxxviii
Fig 6.3.3.1 Power flex 4M Drive
6.3.2 Catalog no. explanation
The catalog explanation of drives is given below
lxxix
Fig- 6.3.2.1 Catalog Explanation
lxxx
6.3.3 Drive connection
Fig 6.3.3.3 Drive connection
lxxxi
CONCLUSION
The working the project was an interesting and all together learning experience. New technology, new progress and new competition are the order of the day the core area to look for a highly fragmented and information intensive activity sequence. The project based on color mixing system using PLC and SCADA. this project helps us to visualise that hoe the actual plant will be setup with the help of SCADA layout, PLC programming tells about the working as to how much time a single task would be completed in whole application. switching plays an important role every plant and here PLC is governor of that. the cope f the study is very useful in these days where everything has been automated. Hence, working with PLC, SCADA, HMI and DRIVES was very interesting and new experience.
lxxxii