SCADA Supervisory Control And Data Acquisition Ramtin Raji Kermani Fall 2005 Computer Sciences &...

SCADASupervisory Control And Data Acquisition

Ramtin Raji KermaniFall 2005

Computer Sciences & Engineering DepartmentShiraz University


Road Map:• What is a Control System?• What is SCADA ?• Where and why SCADA is used?• SCADA architecture• Components of SCADA• Security issues• Modern features


First of all, Lets see what is a Control System ?

A control system, is a system that holds responsible in top of another system (being controlled system) for setting and stabling the system in a predefined state.Nowadays control systems are mostly microprocessor based. (Microcontrollers, PLCs, PC-Based Control systems).

Process being controlledSensor Actuator

Controller System


Example of a monitoring and control system is a system which monitors temperature and switches heaters on and off.


What is SCADA?

SCADA is “Supervisory Control And Data Acquisition”. Real-time industrial process control systems used to centrally monitor and control remote or local industrial equipment such as motors, valves, pumps, relays, sensors, etc.SCADA is Combination of telemetry and Data Acquisition.

SCADA is not just a hardware, neither a software. It’s a concept,it’s a system as a combination of special hardware, software and protocols.

SCADA is used to control chemical plant processes, oil and gas pipelines, electrical generation and transmission equipment, manufacturing facilities, water purification and distribution infrastructure, etc.


Why SCADA is needed ?

The Ability to Remotely collect different plants on different places.

The Ability to control process from a distance.

The Ability to create logs and reports about system’s current and past state.

The Ability to send necessary information to Engineers and operators in real-time using Instant Messaging and SMS.


Where SCADA is used ?

- Electrical generation/distribution,- Natural gas distribution- Fuel Oil storage & flow- Water storage & flow - Lighting- Heating, cooling, ventilation- Fire alarms & suppression- Elevators & escalators- Gates & doors, alarms- Video security cameras - Traffic signals- Process Line Control


SCADA is not a new stuff !

It has been used since the early days of control systems to remotely Control and Monitor current and past state of being controlled system (our plant, factory, etc.)


Early Power System Control (in 1919)

Control room(mimic wall) 1970’s

formerly, all instruments were directly wired to the control room


Late 1990’s Control Centers


A little Confused ?!?!Lets SEE what it is !


Central Monitoring Unit

CommunicationsNetwork

Sensor

Sensor

Programmable Logic Controller

Sensor

Fiber, Radio, Modem,Microwave, Telephone, Wireless, Powerline Carrier

Remote Terminal Unit (RTU)

RTU

RTU


SCADA Hardware

- Field level instrumentation and control devices Sensing field variables, controlling the process and ….

- Remote Terminal Units (RTUs) Send control and monitoring data to MTU. (could be a PLC)

- Master Terminal Unit or MTU (Also called The Master Station)gathering information from RTUs, Monitoring and processing,sending necessary control actions to RTUs.

- Communication System


Going a little more in details …


CommunicationNetwork

Instrumentation

Remote Station

Central Monitoring Station

LAN, WAN, INTERNET


Instrumentation

Remote Station




Instrumentation

Remote Station

Corporate ArchitectureCorporate Architecture


•Focus –Safety–100% Availability–Electro-mechanical–No updating, Aged equipment

•The Language–RTUs, PLCs, IEDs– DNP, Modbus– Low Bandwidth– Analog & Digital

•The Vendors–Allen Bradley(AB)/Rockwell, Honeywell, Siemens, Johnson Controls

•Focus–Security–99.5% Availability–Electronic–Continuous Updating, New

•The Language–Routers, Switches, Servers– IP, Ethernet– High Bandwidth– All Digital

•The Vendors–IBM, Microsoft, CISCO, Dell

Physical Plant Computer Networking

What are the concerns ?


Protocols used in SCADA Systems:

DNP (Distributed Network Protocol)ModbusDeviceNet

Mostly Open Protocol are used in SCADA systems. The most popular protocols are as follows:


SCADA Functionality:

- Data acquisition and displaystore binary & analog data into process data base

- Alarm & Eventsrecord important changes and operator actions

- History data basekeep a record of the process values

- Measured processingcalculate derived values (limit supervision, trending)

- Logging & reporting- Human Machine Interface (HMI):

graphical object state presentation, lists, reports- Operator Command handling

binary commands, set pointsrecipes, batches, scripts (command procedures)


Current stateAlarms and events

Trends and history

Remote Monitoring including:


What is an alarm, an event ?

A&E consider changes occurring in the plant (process) or in the control system(operator actions, configuration changes,…) that merit to be recorded. Recorded changes can be of three kinds:- informative: no action required

(e.g. "production terminated at 11:09")- warning: plant could stop or be damaged if no corrective action is taken "soon"

(e.g. “fuel low")- blocking: the controller took action to protect the plant and further operation is prevented until the reason is cleared (e.g. “Temperature too high")

An event is a change related to:operator actions ("grid synchronisation performed at 14:35"),configuration changes ("new software loaded in controller 21"), andsystem errors ("no life sign from controller B3")


Implementing alarms by variables

An alarm is often encoded as a simple 16-bit word sent by an object (thru PLC) in the plant.Each bit has a different meaning, the error condition is reset when the word is 0.

[120] low oil pressure

121] low water level

[122] trajectory error

[123] synchronisation error

[123] tool error

[131] robot %R1% not ready

…

word


New Trends in SCADA

- Web-Based SCADA systems- Connecting SCADA system to Internet- Gives more functionality to our system- Security issues should be covered

- Using Instant Messaging to report systems status (implemented)- Giving more functionality- Using a reliable instant messaging service

- Using Short Message Service to report critical situations (implemented)- A kind of instant messaging, using Mobile Telecommunication network- Using SMS Server, connecting a cell to PC, setting up a web server and using WAP


Instant Messaging for SCADA

Facilitate the remote monitor and control by utilizing the secure IM

Instant Messaging (IM) is a type of communications service over the Internet that enables individuals to exchange text messages and track availability of a list of users in real-time.

By taking advantage of the near real time feature of IM and richness of the IM presence, we bring forward a secure IM based remote monitor and control system.

LDAP-based device and system managementLightweight Directory Access Protocol (LDAP) [6] specifically targeted at management applications and browser applications that provide read/write interactive access to directories.


Internet

PDA

Cell Phone

`

Computer

IM server

LDAP Server

`

IM Control/Mornitor Proxy

Device 3

`

node1

Device 1

Device 2

Device 4

`

node2

`

Leader node1

firewall

Group key

IM Architecture for SCADA


A simple IM based remote monitor/control interface


SCADA on mobile phoneThe system allows you to use your mobile phone to monitor and control your process from any location. More versatile than a pager system.

You can get detailed alarm messages about any event that occurs in your business.

The application has been written in J2ME

The refresh time is about 2 s

Java application in mobile phone transfers data to/from WWW server.


Last words on SCADA

With new trends and technologies of Computer and Electrical Engineering, there are lots of functionalities available, that we can add to our SCADA system.

You saw that SCADA covers different fields of Computer Engineering like Computer networking, Control, Programming, Embedded Systems, Operating Systems, Real-time Systems and ….

SCADA is a very fast growing technology which is widely used in plants and factories and makes good job opportunities for you in the industry, in computer engineering field..


References:

www.google.comwww.wikipedia.comwww.whatis.comModern SCADA protocols, Elsevier, newness publicationDESY SCADA Experience, EPICS Workshop - Oak Ridgewww.modbus.comwww.DNP.orgEngineering The Architecture Of Distributed Control Systems, Eric RunnerstromMPR AssociatesJoint Program Office for Special Technology Countermeasures, National Defense Industrial Association15-17 July 2003


Questions ? Comments?

Thanks for coming …

Ramtin Raji Kermani, Fall [email protected]

SCADA Supervisory Control And Data Acquisition Ramtin Raji Kermani Fall 2005 Computer Sciences &...

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