LCLS - Undulator Controls
WBS 1.04.02
S. Joshua Stein
Argonne National Laboratory
Office of Science
U.S. Department of Energy
A U.S. Department of Energy
Office of Science Laboratory
Operated by The University of Chicago
[UCS] - Design Philosophy
• The LCLS Undulator Control System (UCS) will be designed as
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a stand-along control system with interfaces to the existing
SLAC control system.
Commercial products will be used whenever possible to avoid
duplication of effort and maximize the benefits of product
maturity.
When a novel design is required, all attempts will be made to
create a “product” which will be useful in both the LCLS-UCS
and the SLAC control system.
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[UCS] - Resource philosophy
• Whenever possible, APS manpower will be utilized in the
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design and implementation of the UCS.
External consultants will be used to help bridge the gap
between SLAC and APS and fill in for engineering manpower
that APS is unable to supply.
- Bob Dalesio (LANL) is currently working with both APS and
SLAC on LCLS control issues. His primary goal is to ease the
communication between the different (independent) control
systems. In addition, his experience in implementing control
systems for multi-laboratory projects make him uniquely
qualified in this role.
- Technical design effort will be outsourced as needed from a wide
pool of talent in the EPICS community.
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[UCS] - Schedule and cost estimates
• Whenever possible, real-world experience was used as a basis
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of estimate for both material and effort costs.
Using engineering experience from within the APS controls
group (who designed and implemented the control system for
the APS and LEUTL), initial estimates were gathered from a
diverse resource pool.
Also, consultant effort has been utilized to check and scrub the
initial UCS schedule.
Many controls requirements are still not defined well enough
for accurate vendor-based quotations. However, making
practical assumptions allowed for creating estimates that we
feel are significantly better than a wild guess.
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[UCS] - Interface with SLAC
• While the UCS will be self-sufficient, there is by necessity a
large amount of communication required between the two
control systems.
- Software
- It is expected that the undulator section will be accessible
from anywhere within the LCLS control structure. As such,
software interfaces will be designed to accommodate such a
requirement, while maintaining the integrity of the individual
control systems.
- To leverage the knowledge of the APS controls group staff
and minimize unnecessary effort, the EPICS control system
platform was chosen for the UCS. EPICS has a proven track
record in the accelerator (and FEL) community.
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[UCS] - Interface with SLAC (timing)
- Timing
- Significant effort will be expended in research and design to
assure that timing information from the injector is available to
the UCS and diagnostics.
- We envision the design of EPICS compliant timing boards
which will reside in both VME and PCI backplanes. These
boards will accept the SLC timing messages and output
EPICS compatible data for all of the subsystems within the
UCS that require timing and time-stamp information.
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[UCS] - Interface with SLAC (MPS)
- Machine Protection
- To protect the undulator components, a machine protection
system (MPS) will be implemented along side the UCS. This
system will be responsible for notifying the LCLS injector of a
shutdown condition when a (machine oriented) dangerous
situation arises.
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[UCS] - Interface with SLAC (commissioning)
• Our goal is to turn over a completely seamless and operational
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undulator system to the LCLS. In this regard, as much as
possible the control system will be designed, tested and
verified at the APS.
Work done at SLAC should be restricted to commissioning and
test.
Training will have to be done after the commissioning process
to allow the operation of the undulator by SLAC personnel.
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[UCS] - Motion platforms
• Fine Motion
- Strongback Cradle
- Current motion platform based on cam movers
- Stepper motors with rotary encoders
- Overall effect to move Quadrapoles
- Purpose: Beam Steering and tuning within the intraundulator space
- Position feedback via external sensors (wire position
monitors covered in 1.04.06.01.01 - Undulator alignment)
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[UCS] - Motion platforms
• Fine Motion
- Scanning Wire Transducer
- Using SLAC standard SWA assembly
- Stepper motors with rotary encoders
- Purpose: Characterize the beam
• Position
• Size
• Shape
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[UCS] - Motion platforms
• Rough Motion
- Diagnostic Stage Selection
- Translate diagnostic “elevator”
- Stepper motors
- Purpose: Select which Diagnostic stage (OTR, SWA, “NoDiagnostic”) is in use at each station
- Camera controls
- Adjust Focus and aperture for both OTR and inspection
cameras
- Stepper motors
- Purpose: “Tune” video picture
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[UCS] - Signal Analysis
• RF BPM [33 in total - one per break section]
- Physics design to be done by SLAC
- Detectors (RFBPM)
- Front-end electronics (amplification)
- Interface with Timing triggers
- Physics requirements will determine ADC resolution and
conversion rate - expected to be 12-14 bits at 40MHz - VME
backplane
- High data rates may necessitate individual processors for each
BPM.
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[UCS] - Signal Analysis
• Charge Monitor [1]
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- Hardware to be designed by SLAC
- Toroid and ICT pair
- COTS VME based ADC
- Interface with Timing triggers
Scanning Wire [33]
- Hardware to be designed by SLAC
- Mechanical Assembly including motors
- COTS VME based ADC
- Interface with Timing triggers
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[UCS] - Video
• OTR Stages [11]
- Acquire and analyze beam
- Position
- Shape
- Size
- 30 Hz capture and analysis rate (1/4 SLAC trigger)
- Large FOV requirement at “reasonable” resolution
- Allows digital “zoom”
- No need for two camera configuration
- Digital interface for frame grabber
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[UCS] - Video
• OTR Stages (continued)
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- Provide operator/scientist “warm fuzzy”
- Rough beam alignment
- Requires video mux and routing via UCS
Observation video [7]
- Color “analog” cameras for visual inspection only
- To be integrated in video mux system from OTR stations.
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[UCS] - Temperature monitoring
• Two thermal sensors per each strongback
- Used for low data-rate trend analysis and alarms
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[UCS] - Vacuum control
• Pump controller interface to control system
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- Whenever possible, commercial pump controllers will be
purchased with standard communications protocols (Serial,
Ethernet, etc.).
Vacuum gauges
- Whenever possible, commercial gauges will be purchased with
standard communications protocols (Serial, Ethernet, etc.).
RGA
- Typically, these devices use embedded PCs as both a user
interface and data acquisition unit. Integrating these into the
UCS will most likely be done via Ethernet based function calls.
Vacuum Valve
- Position monitoring only via binary inputs from limit switches.
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[UCS] - Software
• Control software will be run on the EPICS ‘platform’
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- Defines a low level control schema and implies higher-level
software.
Whenever possible, existing software will be utilized
- Software maturity is an important part of creating a stable control
system.
High level tools will be installed or written to allow flexible
‘science’ software and support the LCLS community as much
as possible without compromising the UCS.
- Correlated and consistent operator screens
- Data archiving
- External software hooks
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[UCS] - Machine Protection System (MPS)
• Scope needs to be fully defined before details extracted
• Must interface with SLAC to inhibit beam trigger
• Local (inter-undulator) machine protection may include:
- Cherenkov detectors
- Motion limit detectors
- Vacuum
- Pressure
- Gas detection
- Valve position
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[UCS] - Machine Protection System (MPS)
• System must be independent of the UCS
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- Regardless of response time of UCS, MPS must be able to
shutdown beam within specified parameters.
Current estimates based off of ‘standard’ MPS components
within the APS and take into consideration:
- I/O types
- Number of channels
- Response time
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[UCS] - Design documentation
• It is important to create and maintain system documentation
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from the beginning of the design process to avoid the “as
built” syndrome.
In particular, all installed hardware and software will be logged
and tracked via ‘live’ tools such as the APS developed IRMIS
suite.
- Maintain an integrated, comprehensive and searchable
database of:
- Installed hardware
- Control software
- Cable
- And all interconnections…
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[UCS] - Cost and Schedule
• Undulator controls initial scrub schedule completely integrated
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within LCLS overall WBS.
- Notable Milestones
- Cradle motion controls complete : February 2005
- RF BPM controls complete : March 2007
- OTR Video capture and analysis complete : June 2005
Material and Effort numbers within reasonable bounds for TPC
- Total Cost : $4.78M
- Total Effort : 5.3 FTE
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[UCS] Cost and resource loading
• An attempt has been made to distribute resource needs over
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the project construction timeline in order to allow the use of
staff and technicians from within the APS controls group
A more balanced profile may be possible with further schedule
scrubbing
- FY04 : 0.1
- FY05 : 3
- FY06 : 1.7
- FY07 : .5
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