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Saturday, 21 August 2010


SCADA is the acronym of Supervisory Control And Data Acquisition. It is used in the fields of data acquisition and monitoring in industries. SCADA is a pure software package and not having any hardware components. It is the monitoring section of a process and the decision making section. It controls all the process taken while doing a particular task.

Normally we use couplet of software, e.g. SCADA- PLC couplet. Here SCADA acts as master and PLC acts as slave. SCADA gives instructions and PLC obeys as per the order. In short control is safe in SCADA hands. It’s more convenient if we use the couplets even if SCADA alone can do all the operations alone.

SCADA operations are categorized under three below explaining sections. Such as- industrial, infrastructure and facility based processes. Industrial process includes manufacturing, production, power generation etc. Infrastructure based process means water treatment, waste water collection, refining etc. Facility process includes building, airport and all public sector processes.

SCADA mainly consists of five subsystems. Each is assigned to perform a particular task. The five subsystems are:

+ HMI or Human Machine Interface- This is an apparatus used to supply data to the human operator and through this he could able to monitor and control
+ A supervisory computer system- This is used to acquire data and to send commands to the process.
+ RTU or Remote Terminal Unit- These are connected to sensors to do a process, Converts sensor signals to digital data and sends this data to the supervisory system.
+ PLC or Programmable Logic Controller- used as field devices in a process, since they are economical, flexible, versatile and much configurable than general purpose RTU’s.
+ Communication- Many modes of communication are available. Communication connects supervisory systems to RTU’s.

Three generation SCADA software is available. They are First generation or Monolithic, Second generation or distributed, Third generation or Integrated. Now third generation is in use.

SCADA has applications on energy management system, multi tasking, automation, industrial control systems, data exchange, pipeline transport, graphical design etc. SCADA made almost all sections under its control tactically. Mainly we use this software in automation purposes. This software is freely available and another advantage is no programming is needed. So even a person who is not good in programming can handle SCADA well and efficiently.


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