SCADA (Supervisory Control Data Acquisition) systems collect and manage data from remote devices across various industries, including power generation and manufacturing. The system architecture consists of a control center, field sites, and communication links, facilitating real-time data collection and analysis. Key components include the Master Terminal Unit (MTU), Human Machine Interface (HMI), Programmable Logic Controllers (PLC), and Intelligent Electronic Devices (IED), contributing to enhanced monitoring, control, and maintenance.

1. SCADA
Supervisory Control Data
Acquisition
By
Asadullah Khan

2.  SCADA refer to a system that collect data from various plants or other remote
devices and then send this data to control computer which Manage and control
this data.

 SCADA USES
 Electric power generation, transmission and distribution
 Water, wastewater and sewage
 Buildings, facilities and environments
 Manufacturing
 Mass transit
 Traffic signals
 Oil and Gas
 Food and Beverage Production

SCADA
Supervisory Control Data Acquisition

3. SCADA Architecture

4.  There three basic Components of SCADA
Architecture.
 Control Centre
 Field Site
 CommunicationLink
SCADA Architecture

5. Control center is responsible to communicate with field component
It has main Function
 together data in real time
 To record System events into a log file
 Information Storage and report for analysis
 Presentation of information in graphic and text form to operator
It consist of the following Components
 SCADA Server or MTU
 HMI Human Machine Interface
 Engineering Workstation
 Data Historian
 Communication router
 All these components are linked by Local area Network
Control Centre

6. Master Terminal Unit
 The MTU is the Heart of Control Center. MTU issues command to RTU/PLC’s/IED ( in field sites) and
asked the desired information from RTU.
 It communication through communication link
Human Machine Interface
 The HMI is hardware and software which enable human operator to control process data
 It provide tool for configuration and
 It also display information that required to supervise the field devices
 It can run on CMS (Central Monitoring System)
 The decision of action of any fault is taken in here
Data Historian
 This is database placed at control center for recording and storage information for any analysis
Engineering Workstation/Programming
 It helps to manage Logistic information and trouble Shooting guide
Control Centre

7. Communication Link
 There is usually long distance between control center and field site. The effective communication is
necessary for effective flow message to and from the MTU and PLC/RTU/IED’S
Link can either be
 Phone
 Cellular network
 Satellite
 Fiber optics

 Remote Terminal Unit
 It support to SCADA System remotely
 Its primary task to controlled collect data from processing equipment and send back to this data to
MTU through communication network
 Occasionally PLC are deployed as field devices to replace RTU’s
Control Centre

8.  Field site consist of Modem and PLC which connect to the
sensors and other field devices through bus network.
 The processed data fro the PLC passes through modem
where it is modulated transmitted through the
communication Modem to control center .
 PLC (Programmable Logic Controller
 It execute Logical function using electrical hardware such
as switches, counter and timer
 It is also responsible for supervisory and data acquisition
through sensors and convert data received from sensors to
digital format
Field site-1

9.  Field site -2 has both WAN card and Intelligent Electronic
devices connected directly to Modem there is no need of
PLC. It is enough intelligent to handle data.
 IED ( Intelligent Electronic Devices)
 It is the basic components of substation perform
protection, Monitoring, controlling and data acquisition
function
 IED are microprocessor based devices with the capability
to exchange data and control signals with another devices
i.e electronic meter, controller )over communication link
Field Site-2

10. The reason why you can see SCADA systems deployed
in many different industries is that these systems can
bring many benefits. Some of them are:
 Receiving real-time information to monitor
equipment
 Remote industrial control
 Storage of performance data for later analysis
 It allows for proactive maintenance and decreases
downtime
Advantage of SCADA