n this PowerPoint, the elements of SCADA systems are explored in detail. The presentation covers key components such as human-machine interface (HMI), data acquisition units, communication networks, and data storage. It also discusses the role of each element in the overall SCADA system and their interaction for efficient process control.

1. MEI POLYTECHNIC
Rajajinagar, Bangalore-560010
Topic :- Elements of SCADA
Presented by:- Shrinidhi and Chetan

2. Supervisory control and data acquisition (SCADA) software is a remote
monitoring and control system that oversees automated processes in all kinds
of factories. Manufacturers use SCADA to keep tabs on operations that
require high-level supervisory control and real-time data acquisition.
Some of the biggest industries that use SCADA include:
Oil and gas
Food and beverage
Automotive
Chemicals
Power and energy

3. SCADA’s Role in Data Collection
This system sends digitized information in real time, and it also automatically
compiles backlogs of all collected data for easy analysis later. This is known as a
process historian and commonly uses a SQL database.
At their core, SCADA systems rely on microcomputers called programmable logic
controllers (PLCs) and remote terminal units (RTUs). PLCs and RTUs
communicate with objects like machines and sensors within your factory and send
gathered information to central processing hubs. These central processors analyze
the data and distribute it to the appropriate parties.

4. Cloud
Elements of scada
Field
Devices
Field
Controllers
HMI

5. Field Devices
At the lowest level we have input and output devices (field devices) such as sensors and
actuators. These devices help monitor and maintain the plant processes and are
controlled by PLC's or RTU's.

6. Field Controllers
RTU PLC
The field devices are connected to RTU's and PLC's which control the bulk of the site.
RTUs rely on microprocessors to convert data collected from sensors into usable data for the
central hub. PLCs operate more locally, allowing users to interface directly with sensors and
make changes without affecting the entire SCADA system.

7. Human Machine Interface (HMI)
HMI devices are master units that allow humans to supervise the SCADA data acquisition process.
Serving as the system’s central processor, the HMI also allows users to regulate and modify the
system as needed. Operators also use HMIs to interact with the gathered data through graphical
user interfaces, usually computer monitors, and compile reports for later use.

8. Network Connectivity
The SCADA system relies on maintaining integrated network connectivity throughout its operation.
Facilities can achieve this using both wired lines and wireless options, connecting conversion units
to the master unit through either landlines or the internet.

9. Field buses, protocols -
The fieldbus links the PLCs of the direct control level to the components in the plant of the field
level such as sensors, actuators, electric motors, console lights, switches, valves and contactors
and replaces the direct connections via current loops or digital I/O signals. The requirement for a
fieldbus are therefore time-critical and cost sensitive.

10. Database or Cloud
The cloud provides reliable and secure storage of data and can be used to provide SaaS (Software
as a service) in the form of data analytics and other applications. For example, an online historian
can be used to provide data analytics. Once analyzed, the data becomes information that can be
accessed by web-enabled HMI software, and then displayed to users. The scalable processing
power on the cloud is useful for performing these tasks, which often require considerable
computing resources. By using a plant floor HMI as a gateway, access to information from the
cloud is available in many forms, including bar charts, graphs, trends, tables, etc.