lcls-i/lcls-ii timing system low level · 2013. 10. 18. · lcls-i/lcls-ii timing system low level...

EPICS Collaboration Meeting Fall 2012 @ PAL

October 22 ~ 26, 2012

LCLS-I/LCLS-II Timing System

Low Level Kukhee Kim for LCLS Timing Team

ICD Software, SLAC National Accelerator Laboratory

October 22, 2012

http://www.aps.anl.gov/epics/index.phphttp://www.aps.anl.gov/epics/index.php


October 22 ~ 26, 2012 2

Event System is a most complicated system!

http://www.aps.anl.gov/epics/index.php


October 22 ~ 26, 2012 3

Accelerator complex for current and future

(LCLS-I, LCLS-II and …)

LCLS

LCLS-II

End of

linac

LCLSLCLS-II

Bypass line

|

Sector 0

|

Sector 10

|

Sector 20|

Sector 30

FEL Injector Test Facility

3 km SLAC LINAC

LTU

Undulators

Interleaved Accelerator Operation

LCLS-III ? LCLS-I

One gun, one destination

120 Hz

LCLS-II

One gun, two destinations,

plus shared tunnel,

plus multibunch?

120 Hz

Separate but synchronous timing systems

360 Hz = 6 x 60 Hz power line timeslots

Independent rate control to each destination

MPS-aware timing

TS4, and TS1

TS5 and TS2

TS6, and TS3



October 22 ~ 26, 2012 4

360Hz – constraint: What is the timeslots?

LCLS-I LCLS-I LCLS-II LCLS-II

FACET FACET



October 22 ~ 26, 2012 5

Legacy Timing System

• SLC timing system

- The Linac is a Pulsed Machine (get a packet of beam per pulse) runs

at a max of 360Hz (120Hz)

- Three Main Timing Signals:

• Hardware

- 476MHz Master Accelerator Clock (runs down 2mile Heliax Main Drive Line cable)

- 360Hz Fiducial Trigger / encoded onto the 476MHz master clock

• Software – MPG (Master Pattern Generator)

- 128-Bit PNET (Pattern Network) Digital Broadcast (contains time slot, trigger setup,

beam type & rate information, beam destination)

- Provide the timing pattern 3 fiducial prior

• Advantage of the Legacy system

- Physicists & Operator are used to the old system

- Provide event patterns 3 fiducial prior

• give a time margin to slow device, or pre-trigger up to 2 fiducial ahead



October 22 ~ 26, 2012 6

Old architecture for the LCLS-I Timing System

D

E

V

~ Linac main drive line

Sync/Div

SLC

MPG

P

N

E

T

119 MHz 360 Hz

SLC

events

LCLS

events

P

N

E

T

m

P

P

D

U

E

V

R

I

O

C

TTL-NIM

convert.

Digitizer

LLRF

BPMs

Toroids

Cameras

Wire Scanner

SLC klystrons

TTL

SLC Trigs

F

A

N

I

O

C

Low Level RF

EPICS Network

Precision


October 22 ~ 26, 2012 7

LCLS-I Timing System

• LCLS Timing System

• Use MRF EVG and EVRs

• Generate event code at 360 Hz based on:

- PNET pattern input (beam code + 128 bits pattern that define beam

path and other conditions, scheduled information)

- Receive MPS*) information (real-time information), and queue it up

into the pattern pipeline (pipeline bypass for quasi real-time)

- Add LCLS information (MPS, BPM calibration, diagnostics and ….)

• Extend the pattern to 192 bits

- Hardwired BCS fault

• Send out timing pattern, including EPICS timestamp with encoded

pulse ID on the timing fiber

• Manage user-defined Beam Synchronous Acquisition (BSA)

MPS*) Please, see the talk for LCLS Machine Protection System (M. Boyes) in hardware solution session (16:30 – 16:50 Oct 22, 2012)



October 22 ~ 26, 2012 8

How to work the EVG

• PNET message broadcast from the old timing system (following a

fiducial, 360 Hz rate)

• PNET receiver in EVG IOC generates IRQ

• EVG software takes the PNET data and uses it to assign the proper

event codes (the PNET data pipelined 3 fiducial ahead)

• Event code setup in EVG one cycle head

• Next fiducial is sent: 360 Hz fiducial signal received by EVG

• The EVG begins to send out the event codes in its Sequence RAM

• The event codes get sent across the timing fiber links to the EVRs

• Inside the EVR, its mapping RAM is set to map a specific HW trigger to

an event code

• when the Event Code matches the same value in the mapping RAM, a

hit is generated and after a programmed delay, a HW trigger is output

form the EVR to the device



October 22 ~ 26, 2012 9

How to work the EVR

• Set trigger delays, pulse width, and enable/disable via

user requests

• Set event code per trigger

• Receive timing pattern ~8.3 msec (3 fiducials prior) before

corresponding pulse. Provides EPICS timestamp to record

processing

• Perform BSA based on tags which are set by EVG in the

timing pattern

• Process pre-defined records when specific event codes

are received



October 22 ~ 26, 2012 10

Timeline for the EVR

F0

0

Fiducial

Time (usec)

B0

Acq

Trigger

1023

Beam Kly Standby

Record processing (event, interrupt)

Fiducial Event

Received

Event Timestamp,

pattern records,

and BSA ready

Receive pattern for

3 pulses ahead

Hardware Triggers

~500 0.3

~40 100

Triggering

Event Codes

Kly Accel

F1

Fiducial

… 2778

110

Start End



October 22 ~ 26, 2012 11

Upgrade Timing system for both LCLS-I and LCLS-II

• Main Goals

• Remove the dependency with the SLC timing system

• Independent EVG for each beam program - LCLS-I, LCLS-II, FACET, XTA and future beam programs

- Promise for independent operation

- Relieves the pain from limited event number (255 limitation)

• Keep compatibility with old system, keep SLAC specific features

(advantage of the legacy system) - Beam code and timing pattern pipeline:

• For pattern aware operation

- BSA

- Event Code Sequence for photon group

• Covers various platforms for EVR: RTEMS, linux, and linuxRT - LCLS-I, and LCLS-II both are going to use various hardware platforms

• VME, PMC, Standard PC, uTCA, and COM-X

• Need to support linux/linuxRT for new hardware platform



October 22 ~ 26, 2012 12

Timing System Upgrade Cont’d

• Upgrade

• Develop a new hardware called VMTG: VME based Master

Trigger Generator which provides 360 Hz IRQ to drive EVG

software instead of the PNET receiver (VMTG in EVG side)

• Develop new software module PABIG: Pattern Bits Generator

which mimics the PNET

• Develop a new software tool to design the event/timing

pattern visually: evGUI1)

• Work on the EVR software to support linux/linuxRT2) for the

new hardware platform: uTCA, and COM-X

evGUI1) Please, see the talk for LCLS timing system for pattern design , evGUI and high level (M. Zelazny)

in the timing system session (15:00 – 15:20 Oct 22, 2012)

Support for linux/linuxRT 2) Please, see the talk for Real-Time Performance Issues on linux/linuxRT (K. Kim)

in the low level application session (14:10 – 14:30 Oct 23, 2012)



October 22 ~ 26, 2012 13

New architecture for the timing system

Device

Analog

Front End

Device

Analog

Front End

EVR

DAQ

IOC

EVR

DAQ

IOC

Linac LLRF Phase Distribution~

LCLS

Local

Oscillator

Synchronizer

Divider

Fiducial

Detector

EV

G

Fa

no

ut

IOC

Timing

Reference

Distribution

360 Hz

119 MHz 360 Hz

119 MHz 119 MHz Fiber Distribution

Timing Event System Fiber Distribution

EPICS CA Network

476 MHz

Device

Analog

Front End

Hardware trigger

signal

Beam

Synchronous

Acquisition

BSA

Data Buffers

To clocked devices

To LCLS-I

EVG

EVR

DAQ

IOC

Master

Oscillator

MPS Link Node MPS Network

LCLS-II CD-2 DOE Review / Aug 21 - 23, 2012



October 22 ~ 26, 2012 14

VMTG

Sector 0 (LI00) VMTG – Master Trigger Generator

• Provides the synchronized 360Hz trigger to the fiducial generator

• Input: 360Hz AC trigger train + 476 MHz MDL RF

• Ouput: 360Hz synchronized trigger

• Then, the fiducial generator makes synchronization with the Master

Oscillator

Sector 20 (IN20) VMTG with the EVG – Master Trigger

Generator

• Provide 360 Hz interrupts with the Timeslot counter

• Provide Timeslot Synchronization

• Input: 60 Hz AC trigger (AC phase C) + Synchronized 360 Hz trigger

• Output: 360 Hz interrupts + timeslot counters



October 22 ~ 26, 2012 15

Disabling PNET allows VMTG control

• PNET task needs to be delayed ~ 150 usec after the PNET IRQ to wait the MPS

message.

• PNET IRQ is using HW_TIMER to make the delay

• The PNET ISR implement 150 usec delay on the HW_TIMER

• The callback for the HW_TIMER releases signal to execute the PNET Task.

• VMTG has configurable IRQ delay

• Configure the VMTG IRQ delay as ~570 usec

• The VMTG IRQ occurs 150 usec after the PNET IRQ

Fiducial

PNET

VMTG

Unknown delay

PNET IRQ

ISR implements the timer

Timer callback releases the signal

to the PNET task

PNET task

VMTG IRQ

The ISR releases the signal to the PNET task

~150 usec

~ 570 usec

MPS message arrives somewhere before the signal.



October 22 ~ 26, 2012 16

Software Stacks for the new EVG application and the

PABIG

PNET VMTG Acromag DIO EVG

BCS SBI Permit BCS Beam Permit 119MHz Clock 360Hz Fiducial Trigger PNET broadcasting

Asyn module VMTG

module

EVG

Drv/Dev

PABIG GenVar Master Beam

Control

Bits 0 to 8

via CA

HW input bits in PABIG EVG Application

EPICS

DB

EDEF reservation for the BSA

PNBN PVs from SoftIOC

SNL program

476MHz Clock

360Hz Trigger

360Hz Fiducial Trigger

2nd NIC

udpComm

mpsComm PNET Task

MPS message

(beam destination &

Permit)



October 22 ~ 26, 2012 17

EVR Software Stacks/ Form factor & OS dependency

VME EVR Hardware PMC EVR Hardware

mrfCommon/mrfVme64

drvErMrf

devErMrf

erRecord BSA

EVR Processing Logic

Event Module for RTEMS/vxWorks

erapi

drvLinuxEvr

devErMrf

erRecord BSA

EVR Processing Logic

Event Module for linux/linuxRT

PMC EVR Hardware

Works with old register map Works with modular register map (new)



October 22 ~ 26, 2012 18

Summary

•Successfully upgraded timing system

• Standalone from the SLC system

• Same code base for LCLS-I, LCLS-II and future projects

• Backward compatibility, keep the advantages from the legacy

system

•Our Team has done the following work:

• Develop new VMTG hardware: John Dusatko

• Develop PABIG software: Till Straumann

• Develop evGUI: Mike Zelazny and Partha Natampalli

• EVG software integration,

EVR software support for linux/linuxRT and real-time performance

issues: Kukhee Kim, Till Straumann, Stephanie Allison



October 22 ~ 26, 2012 19

Related Talks

• LCLS Machine Protection System (M. Boyes)

in hardware solution session (16:30 – 16:50 Oct 22, 2012)

• LCLS timing system for pattern design , evGUI and high level (M. Zelazny)

in the timing system session (15:00 – 15:20 Oct 22, 2012)

• Real-Time Performance Issues on linux/linuxRT (K. Kim)

in the low level application session (14:10 – 14:30 Oct 23, 2012)



October 22 ~ 26, 2012

Thank You!
http://www.aps.anl.gov/epics/index.phphttp://www.aps.anl.gov/epics/index.php

lcls-i/lcls-ii timing system low level · 2013. 10. 18. · lcls-i/lcls-ii timing system low level...

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