An Introduction To SCADA (Supervisory Control And Data Acquisition) For Beginners

An Introduction To SCADA (Supervisory Control And Data Acquisition) For Beginners // On photo Monitor iFIX By ServiTecno via FlickR

Control and Supervision

It is impossible to keep control and supervision on all industrial activities manually. Some automated tool is required which can control, supervise, collect data, analyses data and generate reports. A unique solution is introduced to meet all this demand is SCADA system.

SCADA stands for supervisory control and data acquisition. It is an industrial control system where a computer system monitoring and controlling a process.

Another term is there, Distributed Control System (DCS). Usually there is a confusion between the concept of these two.

A SCADA system usually refers to a system that coordinates, but does not control processes in real time, but DCS do that. SCADA systems often have Distributed Control System (DCS) components.

Components of SCADA

1. Human Machine Interface (HMI)

It is an interface which presents process data to a human operator, and through this, the human operator monitors and controls the process.

2. Supervisory (computer) system

It gathers data on the process and sending commands (or control) to the process.

3. Remote Terminal Units (RTUs)

It connect to sensors in the process, converting sensor signals to digital data and sending digital data to the supervisory system.

4. Programmable Logic Controller (PLCs)

It is used as field devices because they are more economical, versatile, flexible, and configurable than special-purpose RTUs.

5. Communication infrastructure

It provides connectivity to the supervisory system to the Remote Terminal Units.

SCADA System Concept

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 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.

A simple SCADA system with single computer

A simple SCADA system with single computer

SCADA/PLC Video Introduction/Example

Waste Water Treatment SCADA System Raising your Plant IQ

Cant see this video? Click here to watch it on Youtube.

Introducing students to Industrial Programmable Controllers

Cant see this video? Click here to watch it on Youtube.

About Author //


Bipul Raman

Bipul Raman - Bipul Raman (@BipulRaman), a graduate in Electrical Engineering had presented two research papers in National Conferences. He has overtaken and successfully completed a project to design an Automated CB Test-Rig for Light Combat Aircraft at Aircraft Research and Design Center (HAL). Apart from this, he has done several projects at NTPC and Grid Substation. Not only limited to Electrical Engineering, He is also very much passionate in Software Development. He has contributed few of his code to 'Codeplex' ( a Microsoft OpenSource software hosting website ). Visit his complete profile at


  1. Andrew Odihi
    May 13, 2015

    please am just newly recruited in the SCADA dept.need more information.

  2. […] locally. This is largely due to the limited bandwidth typical of communications links between the SCADA central host computer and the field data interface […]

  3. satish
    May 05, 2015

    Very useful domain….regarding plc,scada,dcs

  4. morris
    Apr 06, 2015

    Interested in knowing more for plc and scada filed of work and studies.
    Thank you.

  5. brij kishor rai
    Mar 28, 2015

    Sir me scada ralated information and vedio in electrical engineering career growth me increased .so please help me . more information send me sir

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