Extended LTC
‘Controls Readiness’
Session Summary
Jörg Wenninger AB/OP
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Presentations
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Databases
LSA(*) Core
LSA(*) & Safety
Sequencer
Applications
Timing
Magnet Modelling
Collimator Control
Machine Interlocks
Software Interlock System
Post-mortem
C. Roderick (AB/CO)
G. Kruk (AB/CO)
W. Sliwinsky (AB/CO) & V. Kain (AB/OP)
R. Alemany Fernandez (AB/OP)
D. Jacquet (AB/OP)
J. Lewis (AB/CO)
N. Sammut (AB/OP)
M. Jonker (AB/CO)
B. Puccio (AB/CO)
J. Wozniak (AB/CO)
M. Zerlauth (AB/CO)
The mixture of speakers from the Control and Operation groups
underlines the successful SPS-LHC controls model of strong OP
involvement in controls activities.
(*) : LHC Software Architecture
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Databases
The AB databases are central components of the control system of all CERN
accelerators. They are essential for:

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Settings & configuration.
Alarm system.
Electronic logbooks.
Data logging and monitoring.
Key settings for the control of the LHC (LSA software) share a DB cluster
with the measurement and logging system. This system is reaching its limits
in terms of I/O…
>>> DB upgrade to

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cope with increasing demands.
decouple settings & configuration from logging.
increase availability.
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Evolution of Data Volumes
Estimated volumes for LHC ~ 10 TB/year
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DB Cluster Upgrade
Migration to new DB cluster foreseen ~ end March 2008.
In time for the injector startup.
Oracle RAC 1
Oracle RAC 2
CTRL
CTRL
2 x quadcore 2.8GHz
CPU 8GB RAM
Oracle RAC 3
CTRL
CTRL
11.4TB
usable
Clustered NAS shelf
14x146GB FC disks
LSA Settings
Measurements
Controls Configuration HWC Measurements
E-Logbook
CESAR
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Logging
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LHC Software Architecture - LSA
The LHC Control System ‘LSA’ is now well established and tested. It was
first used in the field in 2003.
LSA is used to :
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Manage equipment configuration
Manage equipment states
Manage machine settings
Drive the accelerators through their cycle
…
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A Tested Control System
The LHC will not be a guinea pig for LSA !
Some CERN accelerators are already under partial of full control of LSA:
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LEIR (partial, since 2005)
SPS and all its transfer lines (complete, since 2006)
Although the LHC will require a large number of dedicated applications for
its equipments, a lot of core functionality was tested and improved on
LEIR and in particular on the SPS.
The LSA core functionality is under permanent test by a large number of
application developers – should be well tested before first beam !
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A Flexible Control System !
Data model & business logic are common for all accelerators
 we can reuse applications
SPS
LHC
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LHC Applications Status
Settings management
Equipment
Instrumentation
General stuff
Trim
kicker
BTVI
sequencer
Drive hardware
RF slow control
Wire scanner
Slow timing
On line model / Knob
Beam dump
Synch rad monitor
Interlock
Settings generation
Equip state
BCT
Alarm
Settings manager
Equip monitor
Fast BCT
Logging
Collimator
BLM
Post Mortem
XPOC
BPM multiturn analysis
Final State Machine
Transverse Feedback
BPM – YASP
RF low level
Beta beating
Tune measurement
Tune feedback
Chromaticity meas.
Chromaticity feedback
Rest Gas Monitors
Schottky
Luminosity monitor
Luminosity scans / display
Wall current monitor
K-modulation
Abort Gap monitor
First working version available
eLTCDevelopment
- Controls Summary
well advanced
Development not started
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Safety
In the CERN accelerators, safety is not just ensured by cutting off the
technical network from the general internet!
There are critical issues related to some machine settings that must
only be accessible to a limited number of experts.
There are two aspects:
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Restrict access : “Role Based Access Control”
Protect and ensure integrity of settings :
“Management of Critical Settings” – MCS
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Role Based Access Control - RBAC
LAFS collaboration – S. Gysin
RBAC works by giving people ROLES and assigning
ROLES PERMISSIONS to access device properties. It
is integrated into the AB controls middleware.
RBAC provides means for
– AUTHENTICATION
– AUTHORISATION
Issues :
– Need a policy.
– Limit the ‘role proliferation’.
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Management of Critical Settings - MCS
Accelerator settings that are part of the MCS have a digital signature
attached to them (based on the public/private key principle).
The digital signature is (re-)generated when the setting is changed (after
RBAC authentication). It is stored in the DB (avoid data ‘corruption’) and
send to the front-end computer where the signature is verified with the
public key
>> Ensures that only authorized ‘clients’ may change the critical settings
Critical setting
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MCS is in the Field !
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Sequencing
In a slow cycling machine like the LHC, the most efficient way to operate is
to automate the execution of task sequences (injection, ramp…).
The SEQUENCER is the software entity that used to run such task
sequences. The sequences can be long and complicated : the sequencer
helps the operators not to forget anything !!
HWC already relies heavily on a sequencer, and a beam sequencer is
under development by a CO / OP collaboration.
The beam sequencer is now used systematically for all controls tests, and
by the time we take beam all essential sequences should be ready.
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Magnet Model : ‘FIDEL’
Aim of FIDEL:
• Describe the magnetic state of the LHC on a circuit by circuit basis
• Provide the settings of the main magnets
• Provide settings for correctors
Example of the b3 decay that should
be predicted by FIDEL:
3
Equation to parameterize the decay
t tin j


t , t inj , , d  d 1  e 


t tin j

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
  1  d 1  e 9
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
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

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b3 (units)
2.5
2
1.5
376
1
0.5
+ parameter values
0
0
200
400
600
800
1000
t (s)
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FIDEL Status
FIDEL parameters have been generated for all circuits.
Most of the data has been collected and validated. Work should be
finished end of March.
The FIDEL model has been implemented in LSA and is under test.
The full model including pre-cycles is expected to be ready for beam
beginning of June.
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Collimator Control
Collimation controls is ready to set the collimators for the first beam.
The high level collimation control system is relying heavily on MCS due
to the criticality of collimator settings.
Still to be demonstrated & tested
• Function driven control for ramp & squeeze.
• Machine protection functionality.
Collimation position setup will be challenging.
• Development of tools and applications required
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Timing
The timing system of the LHC is different from other machines because it is
only ‘loosely’ coupled to the injector chain:
LHC couples to the injector chain only during injection.
The LHC timing system is in place and is being tested.
The coupling and data exchange with the injectors during injection is quite
complex and will have to be tested in May with the SPS comes online with
beam.
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A Common Approach to Interlocks
Beam Interlock
System (BIS)
Powering Interlock
Controller (PIC)
Projects
Design
Safe Machine
Parameters
FMCM
Fail Safe concept
Reliability vs. Availability
RS422
Redundancy
Maintainability
Critical functions in Hw
Sw used only for Monitoring (in
most cases)
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Warm (magnet)
Interlock Controller
(WIC)
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Already Deployed @ CERN
BIS already
operational in SPSLHC Transfer lines &
CNGS
(~ 90 User-Permits)
and in SPS
(~ 30 User-Permits)
PIC operational
WIC already
operational in SPSLHC Transfer lines &
CNGS
(~ 800 nc magnets)
and in LEIR
(~ 100 nc magnets)
and already
participating in
HWC…
FMCM already
operational in both TL
(14 monitors)
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Interlock System Status
All components are ready and almost completely installed.
Progress with the BIS is on hold until missing optical fibres are installed
by TS/EL.
Detailed testing of all input signals to the BIS will be performed in
parallel to HWC.
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Software Interlock System
The Software Interlock System (SIS) complements the HW Interlock
Systems by providing additional equipment monitoring to anticipate
potentially ‘dangerous’ situations.
SIS has been developed for the SPS and the LHC, and it has been used
operationally at the SPS in 2007: the SPS experience was excellent.
The SIS version for the LHC is in the process of being configured. It is
expected to be ready in April 2008.
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Post-mortem System
The Post-mortem system is essential to understand the cause and
consequences of beam dumps and powering failures.
For HWC a PM system is in place. It is being improved continuously to
automate error detections and diagnostics. It is an essential component
of HWC.
The analysis of the beam PM will be a challenge due to the large amount of
data that is collected : ~ few Gbytes of PM data.
Work on beam post-mortem is just starting, it will be concentrated on the
most essential equipment for beam operation.
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Conclusions
The essential components of the LHC control system are ready / will be
ready for beam in June.
A large amount of testing is still required in parallel to HWC to ensure that
the SW will do what it is supposed to do ! This keeps a good fraction of
the CO and OP groups busy.
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