SCADA
Apr 21, 2023
Contents..
Introduction Hardware Architecture Software Architecture Functionality Conclusion References
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Introduction What is SCADA?
What is data acquisition?
Where and why, use of SCADA?Application area :
Industrial processes : chemical, power generation and distribution, metallurgy,
… Nuclear processes : reactors, nuclear waste, ... Experimental physics : HEP laboratories
Application size: 20 k I/O to 450 K I/O, 1 M I/O under development
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Data Server
SCADA ?
SupervisoryControl
AndDataAcquisition
Graphics and Batch processingArchiving, Logging, Access Control, Alarms
Distributed database
PLC’s
Field Bus
Data Server
Control Programs
ERP SystemsExpert Systems
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Architecture
Hardware
Software
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Hardware
Typical Hardware Architecture
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Software Architecture
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Software Architecture Communication
Internal CommunicationAccess to Devices
InterfacingH/W
Multiple communication protocols supported in a single system Support for major PLCs/DCSs but not VME
S/W API ODBC, DDE and OLE I/F to PC Products OPC Client and OPC Server ActiveX Containers
Scalability
DatabaseConfiguration DB, alarm DB, Archive DB, log DB and
RTDB resides in the memory of the servers
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Functionality
Generic SCADA functionality Access Control, MMI, Trending, Alarm Handling, Logging, Archiving, Report Generation, Automation.
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Functionality Contd..
Access Control Users - allocated to groups
group - defined read/write access
MMI multiple screens
library of standard graphical symbols
dragged and dropped
zooming, re-sizing, scrolling...
Links - pages to navigate
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Functionality Contd.. Trending
based on parameters on specific chart
can be predefined or defined on-line
more than 8 trended parameters per chart
both real-time and historical trending
zooming and scrolling
Alarm Handling based on limit and status checking
handled centrally
E-mails can be generated
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Functionality Contd..
Logging, Archiving Data stored in compressed and proprietary format Logging / Archiving either for a set number of parameters or for
a set period of time Logging / Archiving can be frequency or event driven * Logging of user actions together with a user ID VCR facility for playback of stored data Writing logs into RTDB
Report Generation Reports created using SQL type queries to the RTDB or logs Automatic generation, printing and archiving of reports Use of ‘components’ for report generation
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Functionality Contd..
Automation triggered by events
defined in scripting languages
send e-mail ,write into RTDB
recipes
Sequencing
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Development Tools
Project editor Graphics editor Configuration through parameter templates Scripting language Driver Development Tool Kit And more…
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Data Access Mechanism's
Alarm Server typically poll data from the data server( -> impact on network
bandwidth)
More advanced techniques like publish / subscribe are available in some cases
Data from field buses are mainly polled
Field Bus
Data Server
Alarm Server
Polling
Polling
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Conclusion SCADA is a control system with
•More frond end functionality•More interfaces and efficient storage •More record or device oriented configuration•but System wide configuration tools are needed•are less expensive than DCS, but offer different functionality than DCS•And finally various applications
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References
1. www.scadanews.com
2. www.princeton-indiana.com/wastewater/pages/scada/scada-overview.html
3. www.ref.web.cern.ch/ref/CERN/CNL/2002/003/scada/
4. www.sss-mag.com/scada.html
5. www.scada.com