On Time, in Style: Nanosecond Accuracy in Network Control Systems

269 Pages·2017·18.57 MB·English

by  Mathias Kreider

On Time, in Style:
Nanosecond Accuracy
in Network Control Systems
Kreider, M.
PhD August, 2017

Mathias Kreider
Diplomingenieur (FH) Elektrotechnik
On Time, in Style:
Nanosecond Accuracy
in Network Control Systems
DOCTOR OF PHILOSOPHY
COMPUTER SCIENCE
DIRECTOR OF STUDIES: SUPERVISORS:
Prof. Vic Grout Prof. John Davies
Dr. Ralph Bär
Research was undertaken under the auspices of
Glyndwˆ r University and GSI Helmholtzzentrum für
Schwerionenforschung and was submitted in partial fulfilment for
the award of a Degree of the University of Wales
August, 2017

iii
Thesis Declaration
I hereby declare that this work has not been accepted in substance for any degree
andisnotcurrentlybeingsubmittedincandidatureforanydegree.
Date: 03/08/2017
This thesis is the result of my own investigations, except where otherwise stated.
Othersourcesareacknowledgedbyreferences. Abibliographyisappended.
Date: 03/08/2017
I hereby give consent for my thesis, if accepted, to be available for photocopying
and for inter-library loan, and for the title and summary to be made available to
outsideorganisations.
Date: 03/08/2017
Theresearchwascompletedundertheguidanceof:
Prof. VicGrout(DirectorofStudies),GlyndwˆrUniversity.
Date: 03/08/2017

v
Ididn’tgotouniversity. Didn’tevenfinishA-levels.
ButIhavesympathyforthosewhodid.
–TerryPratchett

vii
GLYNDWˆ RUNIVERSITY
Abstract
DepartmentofComputing
DoctorofPhilosophy
OnTime,inStyle:
NanosecondAccuracy
inNetworkControlSystems
byMathiasKreider
The aim of this thesis is to prove it is possible to control and coordinate machines
at sub-nanosecond accuracy. The demonstration case was the conceptualisation of
a control system for large physics experiments, employing high precision timing
technologyanddeterministiccommunication.
The results were empirically proven by means of a control system for a next
generationparticleaccelerator,theFacilityforAntiprotonandIonResearchFAIRin
Darmstadt, Germany. In the scope of this thesis, concepts and prototypes for both
the control system’s master unit, the Data Master, and the employed low latency
network protocol, Etherbone were developed. In addition, a formal model of the
control system was created. Its purpose is to guarantee deterministic operation by
means of an offline analysis ahead of time, assaying latency bounds for a given set
ofcommands.
This research shows that an alarm-based control system with a timing resolu-
tion of 1ns is feasible. A scheme which allows machine schedules to be steered at
runtime is presented and has been validated. Timely arrival can be guaranteed for
trees of alternative command sequences, known ahead of time, as well as for lim-
ited changes during runtime. The proposed approach scales to several thousand
controlled machines. It supports fully deterministic, parallel control processes that
can utilise the full accuracy of the underlying time distribution system. The rate of
controlmessagesisonlydependentonavailablenetworkbandwidth.
The results of this work are already wholly in use at FAIR, controlling a real
world particle accelerator. Etherbone components are also already in productive
useattheEuropeanCentreforNuclearResearchCERNandotherinstitutions,both
forparticleacceleratorcontrolsystemsandcommunicationapplications.