Collimator Controls - CERN Indico

Collimator Controls

• Readiness of collimators control – from bottom to top• State of automated collimator positioning

Extended LTCSession 6 - Readiness of Controls

Friday 07 March 2008 14h30

2008/03/07 MJJ

Collimator Controls

Primary Actors(from bottom – to top)– Alessandro Masi, Mathieu Donze, Arnaud Brielmann, Jerome Lendaro,

Roberto Losito

– Jacky Brahy, Enrique Blanco Vinuela

– Guy Surback, Roland Chery, Nicolas Zaganidis

– Stefano Redaelli, Eric Veyrunes, Delphine Jacquet

Support from LSA team, AB/CO-DM, M.Lamont

Outline

Installation status

h lArchitecture evolution

Functional Status• Environmental Survey

• Positioning & Survey

• Application LayerApplication Layer

Automatic Collimator Positioning (Beam Based Optimisation)

Baseline Architecture (as decided in 2005)

Control roomCentral Collimation Application

Ethernet

Controls Network Data Base

Actual Machine Parameters

Data Base Machine Timing

Control room software:• Management of settings (LSA)• Preparation for ramp• Assistance in collimator tuning

Surface support buildingBLM system

Critical SettingsMachine Timing

Machine Timing Distribution

g– Based on standard LSA components– Dedicated graphical interface for collimator control and

tuning– OP responsibility

C lli t S i S t (CSS)

Underground low radiation area

Collimator Supervisory System(one or two per LHC point)

Synchronisation

Collimator Supervisor System (CSS):– Environmental Supervision through standard PVSS class– Support building, VME / FESA

• Fesa Gateway to Control Room Software• Synchronization of movements

B B d Ali t i itiUnderground, low radiation area

Fan out

• Beam Based Alignment primitives• Takes action on position errors (FB)

– Receives timing, send sync signals over fiber to low level (Ramp & Beam Based Alignment)

– Synchronization and communication (udp) with BLM– CO responsibility

Local Ethernet Segment

Motor Drive Control

PXI

Position Readout and Survey

PXI

Environment Survey

PLC

LHC tunnel

Beam Permit

– CO responsibility

Low level control systems– 3 distinct systems

• Motor drive PXI • Position readout and survey PXI . . . • Environment Survey PLC

– ATB responsibility & CO for Environment

HW Installation status

Today some 75 Collimators are installed.

b l !== 92 by April !

Details in talk of O.Aberle


Temperature readoutAll PLC’ i l– All PLC’s in place

– All installed collimators t dconnected

– All temperature gauges tested except in IP7tested except in IP7

• Very few surprises

• IP7: waiting for 220VIP7: waiting for 220V power connections

HW Installation statusPXI installation– All PXI systems installed

– Test in progress: stages• Pre-Commissioning

– Test signal connectivity

– No motor movement

– All done (IP7 finished yesterday)

• Commissioning 1Requires tunnel access for visual confirmation of– Requires tunnel access for visual confirmation of mechanical movements, swichtches etc.

– IP5, IP6 in progress, followed by IP2, IP8, IP1 (constrained by tunnel access), then IP3, IP7.

– First LVDT-CalibrationFirst LVDT Calibration

• Commissioning 2– Remote tests

– Including PC-gateway & synch-signal

– LVDT-reCalibration, autoretraction, mechanical play

– Finished by last week of May


CSS related hardware– PC Gateways installed in all points except BA7

– Fibers connectivity for synchronisation signals:

• Ready in IP1, IP2, IP3, IP6, IP7• IP8, IP5 before end of March

Temperature monitoring

Based on standard UNICOS / PVSS control environmentPLC programs automatically generated from excel filesPLC supervised by standard PVSS server

PVSS ClientPVSS Client

J Cli

PLC programs automatically generated from excel files(excel files are extracted from Collimation Configuration tables in the DBwith additional dump and alarm limits per temperature sensor

PLC supervised by standard PVSS server• Internal store (Months of data)• Feeds various clients (LoggingDb, Alarm, JapC, Configurable PVSS clients,)

Japc ClientsJapc Clients

Japc ClientsJapc Clients

Collimation Configuration

PVSSServer Alarm System

Logging DB

y

PLC PLC PLC

Temperature monitoring

Configurable PVSS clients

Architecture Evolution

Central Collimation Application

Ethernet





Ethernet




Only considering Position control: 3 Layers

For various reasons (responsibility delimitation) the architecture grew more complex with 4 layersCritical Settings

Machine Timing


Critical SettingsMachine Timing


architecture grew more complex with 4 layers.

A low level Fesa Server was introduced• Longer Execution Path• More resources, more maintenance


Synchronisation


,• Duplicated functionality• For not much benefit• And a complication for MCS

Fan out


Motor Drive Control

PXI


PXISynchronisation

Low Level Fesa(one or two per LHC point)

Low Level Fesa Server taking more and more responsibility (calibration, expert access, …)

What is the solution ?

Beam Permit

Fan out


Motor Drive Control

PXI


PXI

Make Low Level Fesa Server to implement the same property interface as CSS

Suggest to include also synchronisation control in the Low Level Fesa Server

Low Level Fesa

CSS

Beam Permit

in the Low Level Fesa Server.

Architecture (as evolved after 2007 runs)


Ethernet




ATB kindly agreed to include the synchronisation control in the Low Level Fesa

Low Level Fesa Server became de facto the CSSCritical Settings

Machine Timing Low Level Fesa Server became de facto the CSS

Central Collimator Application can (almost) talk directly to ATB CSS implementation as if it was the CO CSS implementation

Many thanks to A.Masi for this 2007 Christmas present.


Synchronisation


Fan out


Motor Drive Control

PXI


PXI

Beam Permit

Architecture (to be completed in 2008)


Ethernet




ATB kindly agreed to include the synchronisation control in the Low Level Fesa

Low Level Fesa Server became de facto the CSS

Optimisation Application

Critical SettingsMachine Timing Low Level Fesa Server became de facto the CSS

Central Collimator Application can (almost) talk directly to ATB CSS implementation as if it was the CO CSS implementation

BLM system

Missing functionality

• CSS is now reporting asynchronously to t (i k f St f )

Beam Based Optimisation(one or two per LHC point)


Synchronisation

requests. (i.e. more work for Stefano).

• Beam Based optimisation primitives not provided

N d i d d h


Fan outNeed an independent process that runs on the PC gatewayLocal Ethernet Segment

Motor Drive Control

PXI


PXI

Beam Permit

PXI and CSS

All functionality defined and ~implemented on PXI(except multi movement option for fast optimisation)(except multi movement option for fast optimisation)

Merge of Fesa Servers

Expert application for LVDTExpert application for LVDT-Calibration• Interacts with Fesa Server to calibrate• Calibration stored in MCS• Calibration stored in MCS• Updates under control of RBAC

Fesa device delivery tool• Takes information from• Takes information from

• Collimation Configuration DB• PXI configuration DB

• Feed Fesa Configuration DB

PXI: Tracking Jaw PositionsSetting

Reading

50 μm 20 sGenerally excellent resolution and performance.

In the tunnel at some locations pickup noise.

20 s 50 μmBeing analyzed.

Setting

10 μm

Reading

20 s

RWA, LHC MAC 12/07 15

S. Redaelli

PXI and CSS

To be finalized and testedF i d i i• Function driven execution

• Machine protection functionalityi d li i• Warning and Dump limits

• Machine Protection limits (MCS) depending on Energy

• Synchronisation• Synchronisation

• Reception of Energy and other Machine Parameters

I t ti ith li ti l (t i d S )• Interaction with applications layer (trim and Sequencer)

New functionality to be commisioned in April.• Actual priority is HW commissioning in the tunnel.

Application Layer

Stefano has provided a lot of work in collaboration with Eric and Delphinewith Eric and Delphine

• Database Table definitions to store collimator configuration• WEB interface• WEB interface

• Collimator configuration database population

• Collimator Control Application

• Definition of parameter space to control collimators settings and limits.

Ad t ti f t i dit ( ith CO/AP) t i li• Adaptation of trim editor (with CO/AP) to visualize more conveniently the collimators following the Beam-IP-family hierarchy

Collimation Configuration

18

Collimator Control Application

Collimator Parameter Space

High level Trim parameter is expressed in Nσ

Absolute values are obtained by folding in the beam based σbeam XXbeam

σbeam is obtained from Momentum, εbeam and βcoll.beam βcoll

• εbeam is the nominal emmittance for which the machine is protected. It is a collimator specific parameter. Measured ε must be < εbeam

• βcoll can be trimmed based on beam based alignment, to correct for local β−beatingβ g

Same hierachy for warning and dump limits.

Collimator Function Trim

Automated Collimator Positioning

94 (up to 160 in final upgrade) collimators, to protect against machine damage and magnet

quenches.

The collimation process is a multi-staged process that require precise (0.1 σbeam) setting of the

jaws with respect to the beam envelope.

Goal for positioning accuracy is ≈20 μm (0.1 σbeam at 7 TeV).Goal for positioning accuracy is 20 μm (0.1 σbeam at 7 TeV).

Actual beam envelope (position and size) may change (from fill to fill ?, by how much?)

Adapt to changing beam parameters to guarantee machine protection and to keep good

l i ffi icleaning efficiency

There are 376 degrees of freedom (4 motors per collimator) (188 if not considering the angle of the jaws)

12 minutes for two positions

30 seconds per degree of freedom (a very efficient operator) still requires about 3 hours.

⇒ We need automated tools and procedures⇒ We need automated tools and procedures

by Chiara Bracco

Beam ProbingTraditional method to establish the beam position, angle and size by touching the actual

beam. (Required with new optics or after substantial changes of beam parameters)

– Starts with producing a well-defined cut-off in the beam distribution.

Beam Loss Monitor Beam Loss Monitor

Starts with producing a well defined cut off in the beam distribution.

– Each collimator jaw is moved until the beam edge is touched. This step defines an absolute reference position for each jaw. (and angle if two motors are moved independently)

Note: Best done from the last element in the cleaning insertion to the firstNote: Best done from the last element in the cleaning insertion to the first• Collimators may stay in place• Machine is better protected against quenches

Disadvantages:• Only possible with low intensity beam (i.e. 5 bunches, extrapolation from 5 to 3000 ??).• Slow if done manually (188 positions )• Delicate (e.g. moving a collimator too far changes the cut-off in the beam distribution).

Fast beam based setupComplements the traditional set-up method (possible with nominal beam intensity).

Adjust positions to reproduce known beam loss pattern.– Based on experience of other accelerators:Based on experience of other accelerators:

Collimation efficiency is more closely related to beam loss patterns than to absolute collimator positions, which are sensitive to orbit deviations, beta beat, etc.

Move jaws in hierarchical order into the beam halo up to the point where a specified beam loss level is recorded in the adjacent beam loss monitors

Beam Loss Monitor Beam Loss Monitor

recorded in the adjacent beam loss monitors.

• Fast if implemented as an automated procedure:– Start at a fixed offset relative to a previously known position (only have to move short– Start at a fixed offset relative to a previously known position (only have to move short

distances, no need to be retracted.– Two beam can be tuned in parallel in the two cleaning insertions IR3 and IR7

Fast beam based setupProcedure in practice:The collimators are set at 1.5 σ retracted with respect to the last optimised value.p p

The jaws are optimised one by one in a precise order.

Optimization by moving in steps of 0.05 σ until the associated set of Beam Loss Monitors (BLM) detects a predefined value of beam lossMonitors (BLM) detects a predefined value of beam loss.The BLM reference levels are found empirically and may be updated from fill to fill.

Timing implications:Starting position –1.5 σ, step size of 0.05 σ (≈50 μm @ 450 GeV)⇒ 30 steps/motor ⇒ 9600 steps in total (only position, no angles, final upgrade).

Available time 5 min. two rings in parallel ⇒ 60 ms per step (16 Hz)

@ 2mm/s 50 μm ⇒ 25 ms per step needed for motor movement@ / μ p p=> 35 ms for driving, data collection, reading BLM, deciding

Fast Optimisation PrimitivesCollimator Supervisory System (CSS)– Send a trigger to adjacent BLM system

on every motor movement

BLM system

on every motor movement– BLM system sends a short “transient”

data to the CSS– Optimization primitive command (on CSS)


SynchronisationMove until BLM-levelParameters• Motors and step size• BLM signals and limits

Synchronisation

Fan outLocal Ethernet Segment

g• Repetition frequency• Maximum steps

– Example:Move Jaw-left in steps of 10 um every 30 ms

Motor Drive Control

PXIPosition Readout and Survey PXI

Beam Loss Monitor Move Jaw-left in steps of 10 um every 30 ms until BL signal reaches 103

This optimization primitive can be used by a central application for

Beam Loss Monitor

a central application for– Beam Probing– Fast beam based optimization

The real chalenge

Motor movement 10ms (20μm)

During the SPS MD, not able to make clean cut in the beam distribution

Beam-dynamics: Re-poppulatution of tails over several 100th of ms.

Long tails after collimator movement,

Large noise components

Motor movement 50ms (25μm)

(70 Hz)12 secLarge noise components

50, 150, 300, 450 &

600 Hz noise

Loss tails with echo

If these effect are also present in the LHC, optimisation will me more challenging.

Fast Optimisation Implementation

To be developed this year.• Implement Multi Step movements at Low Level• Implement Multi-Step movements at Low Level• Development of Optimiser Process

− Beam Based Optimisation Primitivel d f l f d ll− Already useful for operator assisted collimator setup.

• Development of Central Optimisation Control Process− Sequencing the optimisation of the individual jaw positions− Driven by a DB configuration, able to react intelligently if there is

unexpected behaviour.− Initially simple, improve by learning.D t l t d t ?Doctoral student ?

The challenges• Convince BI/SW that transfer of 600 bytes @ 30Hz is sustainable (when

used occasionally for a single BLM crate at the time).• Understanding the beam loss response

Conclusions

Collimation controls is ready to set the collimators for the first beamfor the first beam.

Still to be demonstrated• Function driven control.

• Machine protection functionality still to be tested.

Collimation position setup will be challenging.• Development of tools and applications required• Development of tools and applications required

Collimator Controls - CERN Indico

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