Commit 1ced5d70 authored by Maciej Lipinski's avatar Maciej Lipinski

trivial corrections from reviewer 1

parent d757f438
......@@ -51,7 +51,7 @@
%\boldmath
This article provides a non-exhaustive overview of applications and
enhancements to the White Rabbit (WR) extension of the IEEE1588 Precision Time Protocol (PTP).
enhancements to the White Rabbit (WR) extension of the IEEE 1588 Precision Time Protocol (PTP).
Initially developed to serve accelerators at the European Organization for
Nuclear Research (CERN), WR has become a widely-used synchronization solution
in scientific installations. This article classifies WR applications
......@@ -125,7 +125,7 @@ collaboration with companies.
% the original PTP standard \cite{biblio:P1588WG}\cite{P1588-HA-enhancements}.
% This article attempts at providing a snapshot of the various WR applications,
% the ongoing work on enhancing WR and evolution of WR into IEEE1588.
% the ongoing work on enhancing WR and evolution of WR into IEEE 1588.
The article briefly describes in Section~\ref{sec:wrElements} the portfolio of
readily available WR network elements. It then explains in
Sections~\ref{sec:time-and-freq}-\ref{sec:RFoverWR} different types of
......@@ -133,7 +133,7 @@ WR applications, their concept and use examples,
summarized in Table~\ref{tab:applications}. Application-triggered enhancements are described in
Section~\ref{sec:WRenhancements}. Finally, in Section~\ref{sec:WRin1588} we
briefly describe the integration of WR into the
IEEE1588 standard and we conclude in Section~\ref{sec:conclusions}.
IEEE 1588 standard and we conclude in Section~\ref{sec:conclusions}.
\begin{table}[!t]
\caption{Non-exhaustive list of White Rabbit applications}
\centering
......@@ -348,7 +348,7 @@ within their campus UTC(NIST) and UTC(OP), respectively. All
laboratories are studying WR with different types and lengths of fiber links and attempt to
increase its performance, see Table~\ref{tab:timelabs}.
These studies have shown that the stability (at \textcolor{red}{$\tau=1s$}) of the off-the-shelf
WR switch is 1e-11 (Alan Deviation, ADEV, similar to a typical frequency counter e.g. Keysight 53230A)
WR switch is 1e-11 (Alan deviation, ADEV, similar to a typical frequency counter e.g. Keysight 53230A)
and can be improved to 1e-12 without any modifications to the WR-PTP Protocol, see
Section~\ref{sec:JitterAndStability} and
\cite{biblio:MIKES-50km}\cite{biblio:SYRTE-LNE-500km}\cite{biblio:WR-ultimate-limits}.
......@@ -771,7 +771,7 @@ These requirements necessitate enhancements of WR.
% \label{sec:CSNS-GMT}
% The China Spallation Neutron Source (CSNS) [1] is an accelerator-based pulsed spallation neutron source located in south China, forth of the kind in the world. A "super microscope" for looking into the microstructure of materials, the CSNS has a wide range of application prospects, including in life sciences, physics, chemistry, resources and the environment, and new energy. Completed in March 2018 [2], the facility includes a powerful linear proton accelerator, a rapid circling synchrotron, a target station and three neutron instruments: the General-Purpose Powder Diffractometer (GPPD), Small-Angle Neutron Scattering instrument (SANS), and multi-purpose reflectometer (MR).
% The instrument control system of CSNS is based on White Rabbit network that provides synchronization and real-time control [4]. The experimental control system of CSNS is in charge of target and instrument control. In CSNS, the precise time (T0) of proton hitting the target needs to be measured. The measured time is broadcast to the target stations and the neutron instruments so that these equipment can work relative to T0. This time is also needed to measure the neutron time of flight. The required precision of T0 is 10ns while its transmission to all neutrino instruments must be below 5us [3]. While WR has proven to provide sub-ns accuracy of synchronization, thus meet the 10ns requirement, the tests in [3] confirmed WR’s suitability for the real-time controls (delay below 5us with jitter below <500ns). WR network is used also to synchronize “standard” IEEE1588 devices (NI, BeckHoff PLCs) [4]. The WR Network is synchronized to GPS receiver and rubidium clock. It is composed of 3 WR Switch in 2 layers and 7 WR Nodes
% The instrument control system of CSNS is based on White Rabbit network that provides synchronization and real-time control [4]. The experimental control system of CSNS is in charge of target and instrument control. In CSNS, the precise time (T0) of proton hitting the target needs to be measured. The measured time is broadcast to the target stations and the neutron instruments so that these equipment can work relative to T0. This time is also needed to measure the neutron time of flight. The required precision of T0 is 10ns while its transmission to all neutrino instruments must be below 5us [3]. While WR has proven to provide sub-ns accuracy of synchronization, thus meet the 10ns requirement, the tests in [3] confirmed WR’s suitability for the real-time controls (delay below 5us with jitter below <500ns). WR network is used also to synchronize “standard” IEEE 1588 devices (NI, BeckHoff PLCs) [4]. The WR Network is synchronized to GPS receiver and rubidium clock. It is composed of 3 WR Switch in 2 layers and 7 WR Nodes
%
% \subsection{Neutrinos Detectors}
......@@ -1239,17 +1239,17 @@ With such calibration, a "golden calibrator" will not be required and adding a n
(e.g. SFP) to a WR network will not necessitate a time-consuming calibration of all
devices with this component.
\section{WR Standardization in IEEE1588 (PTP)}
\section{WR Standardization in IEEE 1588 (PTP)}
\label{sec:WRin1588}
The P1588 Working Group \cite{biblio:P1588} is revising the
IEEE1588 standard, due to \textcolor{red}{be finished} in 2019. This group has been studying
IEEE 1588 standard, due to \textcolor{red}{be finished} in 2019. This group has been studying
WR in order to incorporate its generalized
version into the standard \cite{P1588-HA-enhancements}.
This resulted in a third Default PTP Profile, High Accuracy,
% As a result, one of the additions to the standard
% is a third Default PTP Profile: High Accuracy.
that mandates a number of IEEE1588's new optional features. All together, these
that mandates a number of IEEE 1588's new optional features. All together, these
additions are functionally equivalent to WR and allow the support of WR hardware.
Along with the new features, informative annexes are added with a "standardized"
description of the WR calibration procedures \cite{biblio:wrCalibration} and
......@@ -1271,7 +1271,7 @@ project with their
specific expertise and new developments.
% , making it find its way in more applications.
WR has become a \textit{de facto} standard for synchronization in scientific installations
and it is now becoming an industry standard within IEEE1588.
and it is now becoming an industry standard within IEEE 1588.
With its wide adaptation in science, commercial support, upcoming
standardization and EU-funded projects to catalyze applications in
industry, WR will
......
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