Transcript Workshop on the Use of Ethernet as a Fieldbus CERN, 28

Workshop on the Use of Ethernet
as a Fieldbus
CERN, 28 September 2001
Ethernet in the MO/AA control
systems
F.Havart ST/MO
History of use in both
groups
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1996 SPS SPS UNSMOKE system
1999 CDIN and CGAZ safety systems
1999-2000 EREM project
2000-2005 CSAM project
Ethernet
Token Ring
PLC
PCA
MIL1553
ECA
ECA
CDIB
PROFIBUS
WAGO DP
Operator Console
Contacts I/O
SERIAL RS LINK
Middleware
TCP/IP Integration of PLCs and SCADA
I/O - PLC - Fieldbus
Contacts I/O
SERIAL RS LINK
Why Ethernet?
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Completely distributed control environment
Wide areas to cover
Large number of data to process
No real need for determinism
characteristics
Available everywhere at CERN
Well adapted for event driven processes
Why Ethernet?


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Complex architecture but easier to stick to
state of the art safety and risk analysis
methodology
High reliability and/or availability Industrial
equipment use possible
Modularity
Return of experience
Reference: 48 PLC working 24h/day
356days/year for 4 years, 15000 data points

Conclusion so far:
Hardware is extremely reliable (both front
end and network equipment)
Remote maintenance/upgrade/diagnostic
facility
Very efficient coding/cabling for dry
contact/analog data points
Ethernet is a valid medium as fieldbus as
long determinism is not needed
BUT ...

Return of experience
Development cost sometimes high
therefore not recommended for short life
cycle projects
PLC manufacturers are not open minded
Not very well suited for ASCII protocol
translation
Industrial philosophy for SCAM doesn’t fit
the standard computing one
Future?

Future MO architecture for control system
will use PVSS SCADA and Ethernet
LHCX
PVSS
PVSS
UI
Configuration
database
LHC
PVSS
ST/AA
PVSS
TCR
PVSS
Databus
driver
GIF
PVSS
Direct equipment
data acquisition
Future?
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Industrial equipment is already available
(including embedded web server) for 5
years
Industry seems to favour Ethernet and the
trend is to use it at the lowest level of the
acquisition layer
Direct connection serial/Ethernet medium
will solve problem of proprietary system
and protocols