PLC SCADA

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• Introduction of PLC• Introduction of Scada• What is PLC• Importance of PLC• How PLC works• What is Scada• Importance of Scada• How Scada works• Components of SCADA• Scada Architectures• Why Plc-Scada• Benefits Of PLC-Scada• Scope of PLC-Scada

TABLE OF CONTENT


INTRODUCTION OF PLC Programmable logic controllers (PLCs) have been an integral part of factory

automation and industrial process control for decades. PLCs control a wide array ofapplications from simple lighting functions to environmental systems to chemicalprocessing plants. These systems perform many functions, providing a varietyof analog and digital input and output interfaces; signal processing; data conversion;and various communication protocols. All of the PLC's components and functionsare centered around the controller, which is programmed for a specific task.

The basic PLC module must be sufficiently flexible and configurable to meet thediverse needs of different factories and applications. Input stimuli (either analog ordigital) are received from machines, sensors, or process events in the formof voltage or current. The PLC must accurately interpret and convert the stimulus forthe CPU which, in turn, defines a set of instructions to the output systems thatcontrol actuators on the factory floor or in another industrial environment.


INTRODUCTION OF SCADA SCADA (Supervisory Control and Data Acquisition)

Now a days automation system contains PLCs and SCADA software. If you use PLC &SCADA combination the advantages you have is you have better monitoring andcontrol of the plant and also you have access to the information the way you want.SCADA enables engineers, supervisors, managers and operators to view and interactwith the workings of entire operations through graphical representation of theirproduction process.

SCADA runs on a PC and is generally connected to various PLCs and other peripheraldevices. It enables you to generate applications for the most demandingrequirements of plant engineers, operators, supervisors and managers tailoredprecisely to the needs of each plant. SCADA constantly gathers data from the plantin real-time, stores and processes it in the database, evaluates and generatesalarms, displays information to plant operators, supervisors and managers and canissue instructions to PLCs on the plant floor.


PLC: A PROGRAMMABLE LOGIC CONTROLLER

A Programmable Logic Controller, or PLC, is more or less a small computerwith a built-in operating system (OS). This OS is highly specialized to handleincoming events in real time, or at the time of their occurrence.

The PLC has input lines where sensors are connected to notify upon events(e.g. temperature above/below a certain level, liquid level reached, etc.),and output lines to signal any reaction to the incoming events (e.g. start anengine, open/close a valve, etc.).

The system is user programmable. It uses a language called "Relay Ladder"or RLL (Relay Ladder Logic). The name of this language implies that thecontrol logic of the earlier days, which was built from relays, is beingsimulated.


IMPORTANCE OF PLC The PLC is primarily used to control machinery. A program is written for the

PLC which turns on and off outputs based on input conditions and theinternal program. In this aspect, a PLC is similar to a computer. However, aPLC is designed to be programmed once, and run repeatedly as needed. Infact, a crafty programmer could use a PLC to control not only simple devicessuch as a garage door opener, but their whole house, including switchinglights on and off at certain times, monitoring a custom built security system,etc.

Most commonly, a PLC is found inside of a machine in an industrialenvironment. A PLC can run an automatic machine for years with littlehuman intervention. They are designed to withstand most harshenvironments.


HOW PLC LOOKS


HISTORY OF PLC When the first electronic machine controls were designed, they used relays to

control the machine logic (i.e. press "Start" to start the machine and press "Stop" tostop the machine). A basic machine might need a wall covered in relays to control allof its functions. There are a few limitations to this type of control.

Relays fail. The delay when the relay turns on/off. There is an entire wall of relays to design/wire/troubleshoot. A PLC overcomes these limitations, it is a machine controlled operation. Recent developments PLCs are becoming more and more intelligent. In recent years PLCs have been

integrated into electrical communications(Computer network)i.e., all the PLCs in anindustrial environment have been plugged into a network which is usuallyhierarchically organized. The PLCs are then supervised by a control centre. Thereexist many proprietary types of networks. One type which is widely known is SCADA(Supervisory Control and Data Acquisition).


PLC: A PROGRAMMABLE LOGIC CONTROLLER


HOW PLC WORKS How the PLC operates: The PLC is a purpose-built machine control

computer designed to read digital and analog inputs from various sensors,execute a user defined logic program, and write the resulting digital andanalog output values to various output elements like hydraulic andpneumatic actuators, indication lamps, solenoid coils, etc.

Scan cycle: Exact details vary between manufacturers, but most PLCs followa 'scan-cycle‘s format.

Overhead includes testing I/O module integrity, verifying the user programlogic hasn't changed, that the computer itself hasn't locked up (via awatchdog timer), and any necessary communications. Communications mayinclude traffic over the PLC programmer port, remote I/O racks, and otherexternal devices such as HMIs (Human Machine Interfaces).


Input scan A 'snapshot' of the digital and analog values present at the inputcards is saved to an input memory table. Logic execution The user programis scanned element by element, then rung by rung until the end of theprogram, and resulting values written to an output memory table .Outputscan Values from the resulting output memory table are written to theoutput modules. Once the output scan is complete the process repeatsitself until the PLC is powered down.

The time it takes to complete a scan cycle is, appropriately enough, the"scan cycle time", and ranges from hundreds of milliseconds (on older PLCs,and/or PLCs with very complex programs) to only a few milliseconds onnewer PLCs, and/or PLCs executing short, simple code.

HOW PLC WORKS


SCADA(SUPERVISORY CONTROL AND DATA ACQUISITION)

SCADA is a system operating with coded signals over communicationchannels so as to provide control of remote equipment (using typically onecommunication channel per remote station). The supervisory system maybe combined with a data acquisition system by adding the use of codedsignals over communication channels to acquire information about thestatus of the remote equipment for display or for recording functions. It is atype of industrial control system (ICS). Industrial control systemsare computer-based systems that monitor and control industrial processesthat exist in the physical world. SCADA systems historically distinguishthemselves from other ICS systems by being large-scale processes that caninclude multiple sites, and large distances.


SCADA(SUPERVISORY CONTROL AND DATA ACQUISITION)


IMPORTANCE OF SCADA

Scada processes include industrial, infrastructure, and facility-basedprocesses, as described below: Industrial processes include those of manufacturing,

production, power generation, fabrication, and refining, and may runin continuous, batch, repetitive, or discrete modes.

Infrastructure processes may be public or private, and include watertreatment and distribution, wastewater collection and treatment, oiland gas pipelines, electrical powertransmission and distribution, wind farms, civil defense siren systems,and large communication systems.

Facility processes occur both in public facilities and private ones,including buildings, airports, ships, and space stations. They monitorand control heating, ventilation, and air conditioning systems(HVAC), access, and energy consumption.


SCADA TOOL SCADA can be a great tool while working in an environment where

operational duties need to be monitored electronical communicationinstead of locally. For example, an operator can position a valve to open orclosed as desired through SCADA without leaving the control station or thecomputer. The SCADA system also allows to switch a pump or motor on oroff and has the capability of putting motors on a Hand operating status, off,or Automatic. Hand would be referring to operate the equipment locally,and automatic would be scaling the equipment to be operated according toset points the operator instructs on a computer that can communicate withthe equipment through SCADA.


COMPONENTS OF SCADA Remote terminal units (RTUs) connect to sensors in the process and convert

sensor signals to digital data. They have telemetry hardware capable ofsending digital data to the supervisory system, as well as receiving digitalcommands from the supervisory system. RTUs often have embeddedcontrol capabilities such as ladder logic in order to accomplish boolean logicoperations.

Programmable logic controller (PLCs) connect to sensors in the processand converting sensor signals to digital data. PLCs have more sophisticatedembedded control capabilities, typically one or more IEC 61131-3 programming languages, than RTUs. PLCs do not have telemetryhardware, although this functionality is typically installed alongside them.PLCs are sometimes used in place of RTUs as field devices because they aremore economical, versatile, flexible, and configurable.


A telemetry system is typically used to connect PLCs and RTUs with controlcenters, data warehouses, and the enterprise. Examples of wired telemetrymedia used in SCADA systems include leased telephone lines and WANcircuits. Examples of wireless telemetry media used in SCADA systemsinclude satellite (VSAT), licensed and unlicensed radio, cellular andmicrowave.

A data acquisition server is a software service which uses industrialprotocols to connect software services, via telemetry, with field devicessuch as RTUs and PLCs. It allows clients to access data from these fielddevices using standard protocols.

A human–machine interface or HMI is the apparatus or device whichpresents processed data to a human operator, and through this, the humanoperator monitors and interacts with the process. The HMI is a client thatrequests data from a data acquisition server.

COMPONENTS OF SCADA


A Historian is a software service which accumulates time-stampeddata, boolean events, and boolean alarms in a database which can bequeried or used to populate graphic trends in the HMI. The historian is aclient that requests data from a data acquisition server.

A supervisory (computer) system, gathering (acquiring) data on the processand sending commands (control) to the SCADA system.

Communication infrastructure connecting the supervisory system to theremote terminal units.

Various process and analytical instrumentation

COMPONENTS OF SCADA


HOW SCADA WORKS The term SCADA usually refers to centralized systems which monitor and

control entire sites, or complexes of systems spread out over large areas(anything from an industrial plant to a nation). Most control actions areperformed automatically by RTUs or by PLCs. Host control functions areusually restricted to basic overriding or supervisory level intervention. Forexample, a PLC may control the flow of cooling water through part of anindustrial process, but the SCADA system may allow operators to changethe set points for the flow, and enable alarm conditions, such as loss of flowand high temperature, to be displayed and recorded. The feedback controlloop passes through the RTU or PLC, while the SCADA system monitors theoverall performance of the loop.


Data acquisition begins at the RTU or PLC level and includes meter readingsand equipment status reports that are communicated to SCADA asrequired. Data is then compiled and formatted in such a way that a controlroom operator using the HMI can make supervisory decisions to adjust oroverride normal RTU (PLC) controls. Data may also be fed to a Historian,often built on a commodity Database Management System, to allowtrending and other analytical auditing.

HOW SCADA WORKS


SCADA systems typically implement a distributed database, commonlyreferred to as a tag database, which contains data elements calledtags or points. A point represents a single input or output value monitoredor controlled by the system. Points can be either "hard" or "soft". A hardpoint represents an actual input or output within the system, while a softpoint results from logic and math operations applied to other points. (Mostimplementations conceptually remove the distinction by making everyproperty a "soft" point expression, which may, in the simplest case, equal asingle hard point.)

SCADA systems are significantly important systems used in nationalinfrastructures such as electric grids, water supplies and pipelines.However, SCADA systems may have security vulnerabilities, so the systemsshould be evaluated to identify risks and solutions implemented tomitigate those risks.

HOW SCADA WORKS


SCADA ARCHITECTURE


First generation: "Monolithic“ Early SCADA system computing was done by large minicomputers. Common

network services did not exist at the time SCADA was developed. ThusSCADA systems were independent systems with no connectivity to othersystems. The communication protocols used were strictly proprietary atthat time. The first-generation SCADA system redundancy was achievedusing a back-up mainframe system connected to all the Remote TerminalUnit sites and was used in the event of failure of the primary mainframesystem. Some first generation SCADA systems were developed as "turn key"operations that ran on minicomputers such as the PDP-11 series made bythe Digital Equipment Corporation

SCADA ARCHITECTURE


Second generation: "Distributed“ SCADA information and command processing was distributed across

multiple stations which were connected through a LAN. Information wasshared in near real time. Each station was responsible for a particular taskthus making the size and cost of each station less than the one used in FirstGeneration. The network protocols used were still not standardized. Sincethe protocols were proprietary, very few people beyond the developersknew enough to determine how secure a SCADA installation was. Securityof the SCADA installation was usually overlooked.

SCADA ARCHITECTURE


Third generation: "Networked“ Similar to a distributed architecture, any complex SCADA can be reduced to

simplest components and connected through communication protocols. Inthe case of a networked design, the system may be spread across morethan one LAN network and separated geographically. Several distributedarchitecture SCADAs running in parallel, with a single supervisor andhistorian, could be considered a network architecture. This allows for amore cost effective solution in very large scale systems.

SCADA ARCHITECTURE


Fourth generation: "Internet of Things“ With the commercial availability of cloud computing, SCADA systems have

increasingly adopted Internet of Things technology to significantly reduceinfrastructure costs and increase ease of maintenance and integration. As aresult SCADA systems can now report state in near real-time and use thehorizontal scale available in cloud environments to implement morecomplex control algorithms than are practically feasible to implement ontraditional programmable logic controllers. Further, the use of opennetwork protocols such as TLS inherent in Internet of Things technologyprovides a more readily comprehendable and manageable securityboundary than the heterogeneous mix of proprietary network protocolstypical of many decentralized SCADA implementations.

SCADA ARCHITECTURE


WHY PLC-SCADA In recent times, all most every industry use automation or control systems

for working. Every industry needs more engineers to grow their productionrate. Foreign countries have also understood the importance of automation.It is a type of control system which involves information technology andreduces the human manually works in production. For automation industryPLC and SCADA are the most important tools, without these toolsautomation is not possible. It plays a vital role in the world economy as itreplaces all manual systems power.

If you want to get a best job in automation industry, you must have an ideaabout industry’s requirement. Almost every industry needs professionallytrained students who have some experience and detailed knowledge aboutPLC-Scada technology. Candidate needs to get trained in the same, becauseTraining helps them to get practical knowledge and skills that required toget placed in a famous industry. By getting trained with the professionalswho have industry experience, you will get the industry exposure with theindustrial training project as well.


WHY APPIN If you are looking for a better career in an automation industry after

completing your degree, You should get trained from the company who hasexpertise in the same. Appin is a well-known company in the field ofInformation Technology which provides industrial training for all coursesrelated to IT, electronics and telecom field. We also provides the JobOriented Training programs in Information Security/IRM/SecuredApplication programming/ Secured Mobile Application Developmentprogramming in Android, BlackBerry, iOS. Our placement record is betterthan other players in the market.

Our training programs are on the latest technologies with the updatedversions & advanced concepts. Like cloud computing PLC-Scada.


HOW SCADA LOOKS


MANUFACTURING INDUSTRIES


BENEFITS OF PLC-SCADA

PLC and SCADA are the success behind the automation industry. PLC is designedin such a way that it can be used to control multiple inputs and outputs and itcan be handled in extreme temperature changes. Without these twoautomation concepts the automation industry fails. So there is a huge demandfor skilled manpower in PLC and SCADA in automation industry. We cannot eventhink of surviving without this technology even for a day. If the system fails thenthere would be losses of cores of rupees. After the application of PLC andSCADA technology in Industrial automation process.

It is creating a lot of employment opportunities There is a huge demand for skilled manpower in this sector Reduces time Reduces Cost Profit maximization Economies of scale Improved Productivity Quality output Increased Accuracy and speed


SCOPE OF PLC SCADA If you have PLC-Scada training certificate , you will get a chance in different

companies on different profiles specially in the manufacturing industry.Some of the profiles are mentioned below:-

1. PLC-SCADA Trainee2. PLC-SCADA Software Engineer3. Automation and Drives manufacturer at global firms4. PLC SCADA HMI AC DC5. Application Engineer – PLC-Scada6. Electrical Maintenance automation Manager maintenance

Manager PLC SCADA7. Automation Engineer.8. Instrumentation Engineer.


COMPANIES HIRING FOR PLC SCADA

and many more….


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