Il sistema di controllo Tempo Reale dei collimatori dell`LHC

8/14/2019 Il sistema di controllo Tempo Reale dei collimatori dell`LHC

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LHC Collimators Low LevelLHC Collimators Low Level

Control SystemControl System

Dr. A. MasiCERN, Switzerland

AB Dept, ATB group

aless andro .masi@ce rn.ch

Outline

The LHC collimation system

Control requirements

Control system layout

The RT platform used

Control system software architecture

The Motor Drive Control (MDC) The Position Readout and survey (PRS)

Conclusions


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A. Masi, R. Losito

LHC Collimators low level control system

The LHC collimation

system

Control

requirements

Control system

layout


Control systemsoftware architecture

The MDC

The PRS

Conclusions

Circumference: 26.7km

Beam energy in collision: 7 TeVDipole field at 7 TeV: 8.33 T

Luminosi ty:1034 cm -2.s -1

Operating temperature: 1.9 K

A. Masi, R. Losito


One US aircraft carrier at11 knots

A mis-stereed beam can provoke:

1. Damage to the machine

The energy in the two LHC beams is sufficient to melt almost1 ton of copper

2. Quenches:

For example, local transient loss of 4 107 protons at 7 TeV

The LHC collimation system has to protect amachine of 2 billions $ and reduce noise to theLHC experiments absorbing particles out of the

nominal beam coreSee details at: http://lhc-collimation-project.web.cern.ch/lhc-collimation-project

The LHC nominal beam energy is equivalent to:

The LHC collimation

system

Control

requirements

Control system

layout


Control system

software architecture

The MDC

The PRS

Conclusions


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A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout



The MDC

The PRS

Conclusions

A col l imator has two paral le l jaws

Each jaw is controllable in positionand angle

The jaws need to be posit ionedwith 10 um accuracy

A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout


Control system


The MDC

The PRS

Conclusions

The collimation systemis based on different

collimators typesan d

up to 108 col l imatorsdistributed over 6

points in the machine

Jaw posit ions arecorrelated

primary secondarytert iary

Also duringmovements

they have to stay insync


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Reliability: since coll imators protect the machine thefirst requirement of the control system is reliabil ity

Jaws positioning accuracy: fract ion (1/1 0 ) of the

beam size (20 0m !!).

Syncronization between the two m otors of the same

jaw: much less than 1 ms to reduce vibrations

Motion profi les:jaws in different coll imators need tobe locked for more than 20 minutes to movementfunctions sent by a central supervisory application.

The motion start is provided b y a Trigger sent viaoptical fiber

Response delay to a Digital trigger: < 1ms

Syncronization between al l the 5 55 col l imators motorsall along a motion profile: < 10 ms

The LHC collimation

system

Control

requirements

Control system

layout



The MDC

The PRS

Conclusions

A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout


Control system


The MDC

The PRS

Conclusions

Survey frequency: posit ion sensors have to be readat least at 100 Hz to check in Real-Time that the

actual position lies within a given limit function

Synchroniz ation betw een survey process and profile

generation: lag time 200 us

Low level rack dimensions: maximum 40 0mm deep.Limited space in the rack (in one 400 mm deep rackwe need to instal l the controls for at least two

collimators)


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A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout



The MDC

The PRS

Conclusions

A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout


Control system


The MDC

The PRS

Conclusions

PXI systems by National Instruments havebeen used as RT platform because of:

their robustness and compactness

the new R T controllers based on Intel Dual Core

processors with solid state disk are powerful andreliable

the built -in 10 MHz signal architecture allows easydaisy chaining of a synchronization clockacrossmultiple chassis through BNC connectors on the

back of the chassis

3 M gate FPGA cards with analog I/ O are available

Awide variety of cards is available and providedwith LabView RT drivers. This allows saving

manpower on the drivers deveolpment


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A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout



The MDC

The PRS

Conclusions

CMW Infrastructure

CORBA, RDA, JMS

Java Control

Programs

Middleware Client API

Device/Property Model Topic Model

RAD programs

(VB, Excel)C Programs

Clients

DIM (Distributed InformationManagementSystem) is a communication

system for distributed / mixedenvironments based on the

client/server paradigm

The DIM system is currently availablefor mixed platform environments

comprising the operating systems :VMS, several Unix flavors (Linux,

Solaris, HP-UX, Darwin, etc.) Windows

NT/2000/XP and the real time OSs:

OS9, LynxOs and VxWorks. It uses asnetwork support TCP/IP

(See details at http://dim.web.cern.ch/dim/ )

The DIM Server library was

successfully compiled forPharlap

The new Front-End SoftwareArchitecture (FESA) is acomprehensive framework

for designing, coding andmaintaining LynxOS/Linux

equipment-software thatprovides a stable functionalabstraction of accelerator

devicesSee details at:

http://project-fesa.web.cern.ch/project-fesa

A. Masi, R. Losito


T im ing Ca rd

6 6 5 3 w i t h 4 5

ppb c lockstabi l i ty

The LHC collimation

system

Control

requirements

Control system

layout


Control system


The MDC

The PRS

Conclusions


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The LHC collimation

system

Control

requirements

Control system

layout



The MDC

The PRS

ConclusionsAll the PXIs chassis are

syncronized with the 10 MHz

clock.

A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout


Control system


The MDC

The PRS

Conclusions


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A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout



The MDC

The PRS

Conclusions

The signal amplitude is estimated with a

sine-fit algorithm

The algorithm is optimized for RT

implementation

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LVDT working principle

A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout


Control system


The MDC

The PRS

Conclusions

21 LVDTs are read in less than 1 ms with a

negligible jitter. The requir ement about 100

Hz reading frequency is easily satisfied

Multiple readingcharacterization: the

crosstalk has been rejected

carefully choosing the

excitations frequencies

Different SNR scenarioshave been simulated

adding noise on the LVDT

secondaries. The

accuracy will remain

below few um


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A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout



The MDC

The PRS

Conclusions

Trigger delay: 100 usreading jitter: 100 us

Stop reading jitter: 200 usSurvey profile duration: ~20 minutes

Tr igger delay

S t a r t j i t t e r

Pro f i l e dura t ion

Stop j i t t e r

A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout


Control system


The MDC

The PRS

Conclusions


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A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout



The MDC

The PRS

Conclusions

A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout


Control system


The MDC

The PRS

Conclusions

The LHC collimator low level system is reliable androbust: redundancy and fault tolerance have beenbuilt by separating the motor control and theposition survey on different units

PXI running LabView RT has been chosen as lowlevel RT platform

Delay between trigger and motor movements isbelow 100 us

Position sensors can be read a t frequencies close to1 KHz

120 chassis are synchron ized using a 10 M Hz clock

This configuration has been extensively tested inlaboratory and in the CERN SPS confirmingfulfillment of all the specs in a real (noisy)accelerator environment


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A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout



The MDC

The PRS

Conclusions

We Thank R. W. Assmann, M. Jonker,M Sobczak and S. Redaelli for thelong discussions on the architectureof the collimation control system.

Our colleagues of the AB/ATB/LPEsection, in particular A. Brielmann, G.Conte, M. Donze, P. Gander, J.

Lendaro and M. Martino for thefruitful collaboration on theimplementation of the system.

A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout


Control system


The MDC

The PRS

Conclusions

We are indebted to NI for theprecious support received. Inparticular the System EngineeringGroup (Doug, Brent and Christian)and all the R&D people that wereinvolved in this project as well as theEuropean team (Stefano, Joel,Christian).

Last but not least Chris and Giuseppe


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A. Masi, R. Losito


The LHC collimation

system

Control

requirements

Control system

layout



The MDC

The PRS

Conclusions

Thank you very muchfor your attention

Il sistema di controllo Tempo Reale dei collimatori dell`LHC

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