Transcript What is SCADA?

DESY SCADA
Experience
Matthias Clausen
DESY/ MKS-2
14 Nov. 2000
EPICS Workshop - Oak Ridge
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Overview
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14 Nov. 2000
What is SCADA (compared with DCS systems)
Where and Why are SCADA systems used
What do SCADA systems Provide?
Evolution
OPC for SCADA
Benefits
Experience from DESY
Outlook
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ERP Systems
Expert Systems
SCADA ?
Supervisory
Control
Data
Acquisition
And
Graphics and Batch processing
Archiving, Logging,
Access Control, Alarms
Distributed database
Data Server
Data Server
PLC’s
Field Bus
Control Programs
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What, Where and Why
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What is “SCADA”and where is it used
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Supervisory Controls And Data Acquisition
Application area :
 Industrial processes: chemical, power generation and distribution,
metallurgy, …
 Nuclear processes: reactors, nuclear waste, ...
 Experimental physics: Tokamaks, HEP laboratories
Application size:
 20 K I/O to 450 K I/O, two examples of 1 M I/O under development
Why SCADA systems were evaluated for LHC SLC ?
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Reduction of resources
CERN policy of “outsourcing”
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What do SCADA Provide?
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Flexible and open architecture
Basic SCADA functionality
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MMI
Alarm Handling and Trending
Access Control
Automation
Logging, Archiving, Report Generation
Interfaces to H/W and S/W
Interfaces to ERP- and Expert-Systems
Development Tools
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Generic Software Architecture
SCADA Client
ASCII
Files
Commercial
DB
SCADA Developt. Environt.
ASCII
File
Editor
Graphics
Editor
Commercial
Devel.
tool
MMI
Alarm
Display
Log
Display
Library
Client / Server - Publish / Subscribe - TCP/ IP
SCADA Server
Recipe
RT & Event Manager
DB
Export
/
Import
Recipe Data Report
Alarm
Log
Archive
Gener.
Managt Proces
RT
SQL Alarm DB Log DB Archive DB
Ref.
DB
DB
ODBC
DDE
Data
API/DLL
R/W
Private
Driver OPC
EXCEL
Application
Project
Editor
Driver
Toolkit
VME
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Trending
Active X
Controls
Active X
Container
PLC
PLC
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SCADA functions
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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 RDB
 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
* ! Experience @ DESY
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Interfaces to H/W and S/W
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H/W
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Multiple communication protocols supported in a single system
(in particular CERN supported Field busses)
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
 Web clients
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Development Tools
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Project editor
Graphics editor
Configuration through parameter templates
Scripting language
Most processing tools based on IEC 1131
Batch configuration according to S88.1
Driver Development Tool Kit
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Benefits of SCADA
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Standard frame for application
Rich functionality (50 - 100 p-yrs investment)
Reliability and Robustness (very large installed
base, mission critical processes)
Limited specific development
Technical support and maintenance
….. Etc
Enough arguments for the management to promote
SCADA systems.
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Benefits? – not only
More Aspects to take into Account:
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Configuration of SCADA Systems
Data Access Mechanism’s
DESY Experience:
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Namespace: flat vs. OO
System Load
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Network
Processor
Project Management
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Configuration
of SCADA Systems
Data Server
Data Server
PLC’s
Field Bus
Different Namespaces!!
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PLC
Configuration
of SCADA Systems 2nd
SCADA
Communication
Processor
Programs
•Analog-Input
•Value-AI-0
•Value-AI-1
•Analog-Output
•Value-AO-0
•Value-AO-1
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Mapping
Field Bus
•Analog-Input
•Vacuum_VALUE
•Pressure_VALUE
•Analog-Output
•Valve_1_OUT
•Heater_1_OUT
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Configuration
of SCADA Systems 3rd (Alarms)
SCADA
Data Server
•Analog-Input
•Vacuum_VALUE
•Pressure_VALUE
•Analog-Output
•Valve_1_OUT
•Heater_1_OUT
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Alarm Generation
(generic) Alarm scripts:
IF (Pressure_VALUE > Pressure_HIHI_ALARMVAL)
{Pressure_ALARM_HIHI=TRUE
Pressure_ALARM_STATE=CRITICAL
Pressure_ALARM_COLOR=RED }
IF (Pressure_VALUE < Pressure_LOLO_ALARMVAL)
{Pressure_ALARM_LOLO=TRUE
Pressure_ALARM_STATE=ATTETION
Pressure_ALARM_COLOR=BLUE }
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The burden of flat namespaces:
... A lot of individual tags!
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•Vacuum_VALUE
•Pressure_VALUE
•Valve_1_OUT
•Heater_1_OUT
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Pressure_VALUE
Pressure_HIHI_ALARMVAL
Pressure_ALARM_HIHI
Pressure_ALARM_STATE
Pressure_ALARM_COLOR
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Pressure_VALUE
Pressure_LOLO_ALARMVAL
Pressure_ALARM_LOLO
Pressure_ALARM_STATE
Pressure_ALARM_COLOR
2
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Data Access Mechanism's
Alarm Server
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Alarm Server typically poll
data from the data server
( -> impact on network bandwidth)
More advanced techniques like
publish / subscribe are
available in some cases
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Data Server
Data from field buses are
mainly polled
Asynchronous protocols are
difficult to handle
Field Bus
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DESY Experience 1st
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Namespace
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Individual tags for each property blow up the namespace
Flat namespaces of thousands of tags can not be properly
handled without adequate tools
Latest SCADA technology clearly shows the trend to support the
definition of objects which cleans up the namespace
System Load
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Additional –non standard- features like
 calculating alarms for each channel
 temperature conversions ( 6th grade polynomial)
... can cause a lot of overhead which needs to be taken into
account for the calculation of the system load on process
controllers ( here: in a SCADA-like DCS system)
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DESY Experience 2nd
 Project Management
 Small systems can be easily handled with in-house
personal
 Big systems (several thousand of channels) should be
coordinated by an engineering office because of:
 The coordination of the Field Bus (PLC) databases and the
SCADA databases
 The knowledge of the various tools which come along with a
SCADA system
 One of the main arguments for SCADA systems is:
outsourcing
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DESY Experience 3rd
 The SCADA project at DESY failed:
 The project management of the company underestimated
the necessary time to perform the engineering of the
project.
 The company underestimated the overhead for temperature
conversions and the required calculations for alarm
checking
 As a result – the front end processors were not capable to
handle the I/O and the calculations in the specified rate
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Preliminary conclusions
 DCS
system requirements are different from
SCADA requirements
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More frond end functionality
More record or device oriented configuration
System wide configuration tools are needed
 Water tight specifications are necessary
 DCS systems are more expensive than SCADA systems
 A call for tender has to focus on either DCS or SCADA
 SCADA systems are less expensive, but they offer different
functionality
 SCADA and DCS (mixed) can not selected by price
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SCADA @ DESY
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Utility controls @ DESY use EPICS as a SCADA system
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H1 is going to use PVSS for their slow controls
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For TESLA a lot of components will be delivered by
industry:
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Various subsystems can be controlled by SCADA systems:
 Utility Controls (water, energy, air, heating...)
 Cryogenic Controls (cryogenic plants, cryogenic distribution)
 Vacuum Systems (insulation vacuum, beam vacuum)
Problem: Integration of SCADA systems into accelerator
controls
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That’s all Folks
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