Introduction TO Scada

Introduction

SCADA or Supervisory Control and Data Acquisition is a distributed measurement and control system for large-scale industrial automation. SCADA has applications in automated operations like chemical manufacturing and transport, supply systems
and power generation.

How SCADA Works

The SCADA technology was developed as part of Instrumentation Engineering. Monitoring systems such as SCADA have been in use for quite some time now. Such systems are collectively called DCS (Distributed Control System). DCS have conventionally been used for facilities like factories. However such systems are not effective in covering large geographical areas like those involved in gas transport systems. SCADA has been specifically developed to meet requirements covering large territories.

A SCADA system at the machine level consists of a central station for gathering data and managing the overall operation. It also has sensors (these could be Remote Terminal Units or RTUs, or Programmable Logic Controller) placed in proximity to where the action is. The RTU or the PLC collects the information locally and then passes it on to the central station which is often several miles away. RTUs and PLCs today are capable of controlling the operations within its purview through closed loop feedback systems. The central station oversees the overall performance of the one or more RTU/ PLC under its control. SCADA systems also allow operators or supervisors to change the settings as appropriate at the level of the RTU or the central station. Alarming conditions like high temperature are recorded and displayed.