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    SCADA (Supervisory Control and Data Acquisition) is a system that collects data from various sensors at a factory, plant, or in other remote locations and sends this data to a central computer that then manages and controls the data.

    SCADA is a term that is used broadly to portray control and management solutions in a wide range of industries. Some of the industries where SCADA is used are Water Management Systems, Electric Power, Traffic Signals, Mass Transit Systems, Environmental Control Systems, and Manufacturing Systems.

    SCADA as a System

    There are many parts in a working SCADA system. A SCADA system usually includes signal hardware (input and output), controllers, networks, user interface (HMI), communications equipment, and software. All together, the term SCADA refers to the entire central system. The central system usually monitors data from various sensors that are either in close proximity or off site (sometimes miles away).

    For the most part, the brains of a SCADA system are the Remote Terminal Units (RTU). The Remote Terminal Units consists of a programmable logic converter. The RTU are usually set to specific requirements. However, most RTU allow human intervention. For instance, in a factory setting, the RTU might control a conveyor belt’s setting and humans can change or override the speed at any time. In addition, any changes or errors are usually automatically logged and/or displayed. Most often, a SCADA system monitors and makes slight changes to function optimally. SCADA systems are considered closed loop systems and run with relatively little human intervention.

    One of SCADA’s key processes is its ability to monitor an entire system in real time. Data acquisitions including meter reading, checking sensor statuses, etc. that are communicated at regular intervals depending on the system facilitate this. Besides the data that the RTU uses, data is also displayed to a human that interfaces with the system to override settings or make changes when necessary.

    SCADA can be seen as a system with many data elements called points. Usually, each point is a monitor or sensor and can be hard or soft. A hard data point can be an actual monitor, while a soft point can be seen as an application or software calculation. Data elements from hard and soft points are always recorded and logged to create a time stamp or history

    User Interface (HMI)

    A SCADA system includes a user interface called a Human Machine Interface (HMI). The HMI of a SCADA system is where data is processed and presented to be viewed and monitored by a human operator. This interface usually includes controls where the individual can interface with the SCADA system.

    HMIs are an easy way to standardize the facilitation of monitoring multiple RTUs or PLCs (programmable logic controllers). RTUs or PLCs run a pre programmed process, but monitoring each of them individually can be difficult because they are spread out over the system. Because RTUs and PLCs historically had no standardized method to display or present data to an operator, the SCADA system communicates with PLCs throughout the system network and processes information that the HMI easily disseminates.

    HMIs can also be linked to a database, which can use data gathered from PLCs or RTUs to provide graphs on trends, logistic info, schematics for a specific sensor or machine, or even make troubleshooting guides accessible. In the last decade, practically all SCADA systems include an integrated HMI and PLC device, making it extremely easy to run and monitor a SCADA system.

    SCADA Software and Hardware Components

    SCADA systems are an extremely advantageous way to run and monitor processes. They are great for small applications such as climate control or can be effectively used in large applications such as monitoring and controlling a nuclear power plant or mass transit system.

    SCADA can come in open and non-proprietary protocols. Smaller systems are extremely affordable and can either be purchased as a complete system or can be mixed and matched with specific components. Large systems can also be created with off the shelf components. SCADA system software can also be easily configured for almost any application, removing the need for custom made or intensive software development.

    Additional Reading on SCADA Systems

    • rekha

      any one can tel me the details of scada…and job opp..plz frnz help….send the information to srekhaece@gmail.com



      What is the difference between SCADA & PLC ?

    • shammas

      I am a diploma student for electronics & instrumentation.Whether SCADA has any job oppurtunities & where does this course offered ?

      • Andy

        There is a school for SCADA (i think the only school for just SCADA) in Mitchell South Dakota at Mitchell Technical Institute. I am a graduate of the program myself and i can tell you that if you are already an Electronic Tech you will not need the program. they are pretty enterchangeable

    • John

      Can someone explain the differences between SCADA, PLC,RTU and Transducers

      • Andy

        SCADA is the system that more or less interperts the Data from a PLC
        a PLC is in the simplest form just an industerial computer it gets data from a Transducer is just a device used to interpet one type of energy and turn it into a form that can be read by the PLC and then in turn sent to the SCADA system

        A RTU (radio transmitting unit) is just like a radio that takes the information from the PLC and sends it wirelessly to another RTU that is connected to the SCADA system

        the way i have explained this is just on direction you have to understand that everything works back and forth all the time.

        • ben

          pliz give one practical or aspect or example how SCADA works.i am really more interested in knowing in depth about SCADA.for example SCADA system used to report water level/flow to/ in tank

        • kyle

          Andy, RTU actually stands for Remote Terminal Unit not Radio Transmitting Unit. Your description of an RTU is partially incorrect, for a simple description of what an RTU is just do a simple search on the web for RTU + SCADA. Hope that helps.

    • ossama

      HI. it’s agood description for SCADA system

    • Asi

      Very good snd simple description

    • pvbrowser

      Our http://pvbrowser.org is a Open Source SCADA framework.
      The server may also run on OpenVMS
      where the client can run on Linux/Unix/Windows and OS-X
      It uses Qt.

    • Andy


      My Name is Andy, I am a Graduate of Mitchell Technical Institute In there SCADA Program. I have been doing Electrical work in many different environments and have a very good understanding of how most things in the world of SCADA work. I would like to offer my Knowledge to anyone that has any questions about how SCADA works or what it is or how to use it. Please if you have any questions please send me a message and i will try to answer as soon as i can if i dont know the answer i will do my best to find it for you.

      Thank you all

      • Ravi

        hia Andy,
        I jus wanna to know abt SCADA in simple language coz i have my subject in engg. 7th sem elec.n elex. branch so as soon as possible please revert me coz i hv my xams also in dec 201. here is mine mail id “prakash.ravi07@yahoo.com “.i ll b very thankful to u …..

        Ravi Prakash

      • Ravi

        hia Andy,
        I jus wanna to know abt SCADA in simple language coz i have my subject in engg. 7th sem elec.n elex. branch so as soon as possible please revert me coz i hv my xams also in dec 201. here is mine mail id “prakash.ravi07@yahoo.com “.i ll b very thankful to u …..


      • wally

        Dear Andy,

        I apreciete your effort if you have any thing on SCADA as representation on Power Point !

        My e-mail walykab@hotmail.com

        Have a nice day !

        Wally Kabbara

    • R.Saravanan

      Dear Sir,
      I want to install the SCADA system in an rubber product manufacturing company.I want to contact an consultant engineer near DELHI in INDIA for the same.


    • siddiqui fouzia

      hello Andy…….
      i want to know about scada bcoz i have to give the seminar on this topic….
      plz help me as soon as posible 

    • Shiva

      hi guys… i want some basic information on SCADA … so plz send me the informaton \to  shivas485@gmail.com

    • isachar

      hi andy i’m electronics engineering graduate i’m inerested in scada, can you give me a hand out about scada, a pdf files,and send the links in my email account isachar_paran@yahoo.com…thank u for sharing you knowledge your a big help to us…. 

    • D Morekoo

      I am new to scada system and i am electrical engineer technician. I would like to be introduced to this course online . In anticipation of your corporation, I thank you.


    • Akhtar Aziz

      I am associate technical in mechanical and working in power plant since 20years but electrical side specially in SCADA system face problem.Lay out of fiber optic is no problem
      only the connection between the system and component and attachment give some problem.
      Pls help me to work on confidently to run the system 

    • habeeb


      What are the problems you are facing, is it network connectivity issues or measurements issues.


    • Modou

      1)    What are the components in a scada system?

    • Kamek Sadek El Sharqawy

      I am new to scada system and i am electrical engineer. I would like to be introduced to this course online . In anticipation of your corporation, 
      Thanks and Appreciated

    • Kamek Sadek El Sharqawy

      I am new to scada system and i am electrical engineer technician. I would like to be introduced to this course online . In anticipation of your corporation, 
      Thanks & Appreciated


    • kiran

      i just awnted to know whats the cost of installing scada system ?

    • shekher wadhwa

      Hello Andy
      Plz. my help Scada programming related job. find me.

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    • Kimberly

      If you could use extra profit of about 50 bucks to 300 bucks on daily basis for doing jobs on your computer from home for several hrs daily then this may interest you…

    • etta.bartlett2


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