This a basic intro to SCADA. There are very many opportunities to create and improve such systems.

1. Supervisory Control And Data Acquisition
•Definition and Examples of SCADA systems
•Designing a SCADA system(interface and sensors)
•Building a SCADA system using LABVIEW 2013
•Implementation and Troubleshooting
BY WINNIE MBAU

2. SCADA Definition and Examples
S-Supervisory, C-Control And Data Acquisition
 A SCADA system is an automated centralized monitoring and control function/system for processes
with data logging capability used to control and monitor geographically dispersed sites over long-
distance communications networks, including monitoring alarms and processing status data.
 Based on information received from remote stations, automated or operator-driven supervisory
commands can be pushed to remote station control devices, which are often referred to as field
devices= control local operations such as opening and closing valves and breakers, collecting data
from sensor systems, and monitoring the local environment for alarm conditions
 SCADA systems are typically used in industries such as electric, water, oil and gas, transportation,
chemical, pharmaceutical, pulp and paper, food and beverage, textile industry and other discrete
manufacturing processes.
 SCADA systems are also used in distribution systems such as water distribution and wastewater
collection systems, oil and gas pipelines, electrical power grids, and railway transportation systems.

3. FEATURES OF A SCADA SYSTEM
Dynamic
Process Graphic
–HMI
Alarm History
Real time trend
&Historical
Time Trend
Data base
connectivity
Device
Connectivity
Script and
Security
Device
Connectivity

4. FUNCTIONS OF A SCADA SYSTEM
 A SCADA system performs four functions:
1. Data acquisition- Using sensors (either digital or analog) that are directly interfaced with
the managed system.
2. Networked data communication- remote telemetry units (RTUs). These are small
computerized units deployed in the field at specific sites and locations that report to
SCADA master units (ie larger computer consoles that serve as the central processor for
the SCADA system)
3. Data presentation- HMI Human machine Interface
4. Control- control relays that are directly interfaced with the managed system can be
switched ON/Off from the Central processor AND PLCs.

5. ARCHITECTURE OF SCADA
Power supply
Digital or Status inputs
Analog inputs
Digital (control) outputs
Analog outputs
Software and logic control
• IED communications
• Master communicationsCommunications

6. Architecture cont
HARDWARE
•CLIENT LAYER man machine interaction
•DATA SERVER Layer handles process data control activities. This is where PLCs are connected.
SOFTWARE
• SERVERS responsible for data acquisition and handling
COMMUNICATIONS
• INTERNAL COMMUNICATIONS server to sever & server to client
• ACCESS TO DEVICES data servers poll controllers at user defined intervals.
INTERFACING

7. RTU
remote terminal unit (RTU) is
a microprocessor-controlled
electronic device that
interfaces objects in the
physical world to a distributed
control system
or SCADA (supervisory control
and data acquisition) system by
transmitting telemetry data to a
master system, and by using
messages from the master
supervisory system to control
connected objects. Another
term that may be used for RTU
is remote telecontrol unit.

8. PLC in SCADA
system
(PLCs) connect to sensors
in the process and convert
sensor signals to digital
data. PLCs have more
sophisticated embedded
control capabilities than
RTUs. PLCs do not have
telemetry hardware,
although this functionality
is typically installed
alongside them. PLCs are
sometimes used in place of
RTUs as field devices
because they are more
economical, versatile,
flexible, and configurable.

9. HMI
Human Machine Interface
HMI is the apparatus or
device which presents
processed data to a human
operator, and through this,
the human operator
monitors and interacts
with the process. The HMI
is a client that requests
data from a data
acquisition server.

10. ADVANTAGES
Flexible
simple
reliable
Efficient
with less
manpower
Portable
and cost
efficient
Self-
checking
and
readability
Alarming-
Early Fault
Detection
Data
logging

11. DISADVANTAGES
Network Security Risks
Lack of trained personnel
Initial capital investments

12. DESIGN AND IMPLEMANTATION OF SCADA
SYSTEMS
 Consider a simple system where an alarm goes on when the water level of a
tank reaches maximum. The operator has the ability to switch off the pump at
the sound of the alarm 500meters away. SCADA systems are basically the
same. However you need to monitor more complex machines with more than
one output. So a real-life system needs to monitor hundreds or thousands of
sensors. Some sensors measure inputs into the system (for example, water
flowing into a reservoir), and some sensors measure outputs (like valve
pressure as water is released from the reservoir)
 Some of those sensors measure simple events that can be detected by a
straightforward on/off switch, called a discrete input (or digital input).
 Some are analog sensors, which can detect continuous changes defined by a
bottom and top level.. Analog sensors are used to track fluid levels in tanks,
voltage levels in batteries, temperature and other factors that can be measured
in a continuous range of input.For example, you may want the temperature in a
server room to stay between 60 and 85 degrees Fahrenheit. If the temperature
goes above or below this range, it will trigger a threshold alarm.

13. Cont…
 Data Communication is required to monitor multiple systems from a central location, so you
need a communications network to transport all the data collected from your sensors.
 Early SCADA networks communicated over radio, modem or dedicated serial lines.
 Today, more and more data is being transmitted over optical fiber using SONET. SONET
(Synchronous Optical NETworking) is a standardized protocol that transfers digital
information over fiber optic networks. For security reasons, data should be kept on closed
LAN/WANs without exposing sensitive data to the open Internet.
 Real SCADA systems don't communicate with just simple electrical signals, either. Data is
encoded in protocol format.
 Sensors and control relays are very simple electric devices that can't generate or interpret
protocol communication on their own. Therefore the remote telemetry unit (RTU) is needed to
provide an interface between the sensors and the network. The RTU (Remote Telemetry Unit)
encodes sensor inputs into protocol format and forwards them to the SCADA master; in turn,
the RTU (Remote Telemetry Unit) receives control commands in protocol format from the
master and transmits electrical signals to the appropriate control relays..

14. APPLICATION AREAS OF SCADA
 Power
 Oil & Gas
 water and waste management
 Process Industries including petrochemicals,
fertilizers, cement, paper and pulp, steel industries,
and aluminum plants.

15. Basic SCADA Level program.