collimator controls readiness of collimators control – from bottom to top state of automated...

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 statusArchitecture evolutionFunctional Status

• Environmental Survey• Positioning & Survey• Application Layer

Automatic Collimator Positioning (Beam Based Optimisation)

LHC tunnel

Underground, low radiation area

Surface support building

Control room

Baseline Architecture (as decided in 2005)

Collimator Supervisory System(one or two per LHC point)


BLM system

Beam Permit

Central Collimation ApplicationCentral Collimation Application

Ethernet

Controls Network Data Base

Actual Machine Parameters

Data Base

Critical Settings

. . .

Machine Timing

Machine Timing Distribution

Synchronisation

Fan out

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

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

tuning– OP responsibility

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

• Fesa Gateway to Control Room Software• Synchronization of movements• 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

Low level control systems– 3 distinct systems

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

– ATB responsibility & CO for Environment

Local Ethernet Segment

Motor Drive ControlMotor Drive Control

PXIPosition Readout and Survey

Position Readout and Survey

PXIEnvironment Survey

Environment Survey

PLC

OP

CO

COATBATB

HW Installation status

Today some 75 Collimators are installed.== 92 by April !Details in talk of O.Aberle


Temperature readout– All PLC’s in place– All installed collimators

connected– All temperature gauges

tested except in IP7• Very few surprises• IP7: 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 1– 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-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 monitoringBased on standard UNICOS / PVSS control environment

PVSSServer

PLC PLC PLC

Logging DB

PVSS Client

Alarm System

PVSS Client

Japc ClientsJapc Clients

Japc ClientsJapc Clients

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

Collimation Configuration

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

Configurable PVSS clients

Temperature monitoring



Beam Permit


Ethernet



Data Base

Critical SettingsMachine Timing


Synchronisation

Fan out





PXI



Beam Permit


Ethernet



Data Base



Synchronisation

Fan out





PXI

Low Level Fesa(one or two per LHC point)

Low Level Fesa(one or two per LHC point)

Architecture Evolution

Only considering Position control: 3 Layers

For various reasons (responsibility delimitation) the architecture grew more complex with 4 layers.

A low level Fesa Server was introduced• Longer Execution Path• More resources, more maintenance• Duplicated functionality• For not much benefit• And a complication for MCS

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

What is the solution ?

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

Architecture (as evolved after 2007 runs)

Beam Permit


Ethernet



Data Base



Synchronisation

Fan out

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

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.





PXI



ATB

Architecture (to be completed in 2008)

Beam Permit


Ethernet



Data Base



Synchronisation

Fan out

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

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

Missing functionality

•CSS is now reporting asynchronously to requests. (i.e. more work for Stefano).

•Beam Based optimisation primitives not provided

Need an independent process that runs on the PC gatewayLocal Ethernet Segment




PXI

BLM system

Beam Based Optimisation(one or two per LHC point)

Beam Based Optimisation(one or two per LHC point)



Optimisation ApplicationOptimisation Application

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

Merge of Fesa Servers

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

Fesa device delivery tool• Takes information from

• Collimation Configuration DB• PXI configuration DB

• Feed Fesa Configuration DB

RWA, LHC MAC 12/07 15

PXI: Tracking Jaw PositionsSetting

Reading

50 m

20 s

20 s

50 m

Setting

Reading

10 m

20 s

Generally excellent resolution and

performance.

In the tunnel at some locations pickup noise.

Being analyzed.

S. Redaelli

PXI and CSS

To be finalized and tested• Function driven execution• Machine protection functionality

• Warning and Dump limits• Machine Protection limits (MCS) depending on Energy

• Synchronisation• Reception of Energy and other Machine Parameters• Interaction with applications layer (trim and Sequencer)

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

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

• Database Table definitions to store collimator configuration• WEB interface• Collimator configuration database population

• Collimator Control Application• Definition of parameter space to control collimators settings and

limits.• Adaptation of trim editor (with CO/AP) to visualize more

conveniently the collimators following the Beam-IP-family hierarchy

Application Layer

18

Collimation Configuration

Collimator Control Application

Collimator Parameter SpaceHigh level Trim parameter is expressed in N

Absolute values are obtained by folding in the beam based beam

Xbeam

beamis obtained from Momentum,

beam and coll.

• beam is the nominal emmittance for which the machine is protected. It is a collimator specific parameter.

Measured must be < beam

• coll can be trimmed based on beam

based alignment, to correct for local beating

Same hierachy for warning and dump limits.

Collimator Function Trim

Automated Collimator Positioning94 (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 beam) setting of the jaws with respect to the beam envelope.Goal for positioning accuracy is 20 m (0.1 beam 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 cleaning efficiency

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

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

We need automated tools and procedures

by Chiara Bracco

12 minutes for two positions

Beam Probing

Beam Loss Monitor Beam Loss Monitor

Traditional 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.– 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 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 setup

Beam Loss Monitor Beam Loss Monitor

Complements the traditional set-up method (possible with nominal beam intensity).

Adjust positions to reproduce known beam loss pattern.– 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.

• Fast if implemented as an automated procedure:– 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.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 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⇒=> 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 sends a short “transient” data to the CSS

– Optimization primitive command (on CSS)

Move until BLM-levelParameters• Motors and step size• BLM signals and limits• Repetition frequency• Maximum steps

– Example: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 Probing

– Fast beam based optimization



BLM system

Synchronisation

Fan outLocal Ethernet Segment




PXI

Beam Loss Monitor

The real chalengeMotor movement

10ms (20m)

Long tails after collimator movement,

Large noise components

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

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.

Motor movement

50ms (25m)

(70 Hz)

50, 150, 300, 450 &

600 Hz noise

Loss tails with echo

12 sec

Fast Optimisation Implementation

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

− Beam Based Optimisation Primitive− 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.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 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

collimator controls readiness of collimators control – from bottom to top state of automated...

Documents

position control

collimator tuningbased

tunnel access

low level ramp beam

sync signals

alarm limits

synchronisation signals

lsa team