Andrew Johnson wrote:
ILC-Controls folk: I'm forwarding Ron Rechenmacher's message to the
EPICS developers who are working on an enhanced timing/event API that
will be included in EPICS Base R3.14.10.
EPICS Guys:
The ILC community are discussing timing/event systems, see the
messages forwarded below.
Do any of you have a network (probably UDP-based) driver pair for the
(old or new) Event system? I don't see any particular difficulty with
creating one that would plug in to the Time Governor code, but I don't
remember hearing anyone talking about having created one.
Not at the moment (unless somebody has written such one and forgotten to
tell :-) ). However, writing such a driver would not
be a big deal, for most of the functionality. I would need to take a
close look at some of the issues. I would like to revise
some of the concepts with the drivers anyway (since many years...)
That brings up another point for the Time Governor: should (do) we
have a standard API for event generators? IIRC the Time Governor
stuff is currently just for event receivers, does it make sense to add
an API call for event system drivers that generates a particular event
number? This obviously isn't going to be useful for high precision
timing, but it could be useful, including as a way to implement a
'time distribution over event system' time driver in a generic manner
(although that would almost certainly break compatibility with
existing clients).
The Time Governor has also a part for event generators, at least in our
(Babak's) version. We have a mixture of (SLS) 'old' and 'new' (Diamond
& later) event
cards and need to distribute some global time information over the
network (and also keep the event time in sync with wall clock time with
a servo loop.)
Adding an API call to generate an event number is simple, but it is not
obvious for me at the moment how that could be used in time distribution
(it is late Friday afternoon over here ...)
By the way, I could not resist to comment on this:
The jitter and the drift with this system are several of 10ps
There must be something wrong with the setup (I am not sure whose
comment this was...) we get a jitter well below 10 ps, measured with a
LeCroy SDA6000 (and the 230-series EVG/EVR). Long-term drift can of
course depend on many issues, mainly (ambient) temperature change, but
we have not seen any problems with this at SLS, and when the devices are
operated in steady state.
best regards,
Timo
ps. And yes, the Micro-Research system is indeed the result of evolution
from the Fermilab-APS line. We at SLS took the APS system
as a reference, redesigned it (with Micro-Research) so that we could use
it for all timing including injection. For Diamond we then collaborated
and had a chance to implement many things which were not possible or
feasible at the time we were building SLS. Shanghai Light Source is
indeed using them, as well as the Australian Light Source. All these
places have contributed several good ideas along the way :-)
- Andrew
-------- Original Message --------
Subject: Re: Timing/Event Systems
Date: Fri, 14 Dec 2007 09:58:51 -0600
From: Ron Rechenmacher <[email protected]>
Reply-To: [email protected]
To: Dalesio, Leo `Bob` <[email protected]>
CC: Kazuro FURUKAWA <[email protected]>, Andrew Johnson
<[email protected]>, Frank Lenkszus <[email protected]>, [email protected],
[email protected], [email protected]
Hi,
I suggest to anyone on this list that can influence the development of
the
interface software that the software be constructed in such a way as
to allow
(either as a compile time config or a runtime config) a way to work
without
the hardware (simulation mode -- perhaps allowing for stimulus via
network
messages). CERN has recently added such capability to their front end
software
environment - see 2nd dark bullet on the 3rd page of:
http://ics-web4.sns.ornl.gov/icalepcs07/WOPA04/WOPA04.PDF
I've been thinking about this for several years and I thing such thinking
ultimately can facilitate collaboration on such system.
--Ron
LCLS is using this timing on RTEMS. Contact Dayle Koturi or Till
Straumann ([email protected] and [email protected]) It
was installed and ported there with much help from Timo and Eric.
At NSLS II we are considering a modification of this approach as we
are looking to develop a standard data and timing distribution to
embed into our FPGA based device controllers. We are working in
concert with Larry Doolittle at LBL while inclulding Timo at SLS,
Jukka at Micro Research, and Rok Ursic at I Tech (libera BPM folks).
Bob
-----Original Message-----
From: [email protected] on behalf of Kazuro FURUKAWA
Sent: Fri 12/14/2007 5:45 AM
To: Andrew Johnson
Cc: Frank Lenkszus; [email protected]; [email protected];
[email protected]; Kazuro FURUKAWA
Subject: Re: Timing/Event Systems
Hello,
Discussion with Ron Rechenmacher and other Fermilab people were very
interesting. Thank you Ron.
We have started some software evaluation based on the discussion. But
is may take time.
For the Event system;
As far as I understand, Timo at SLS (Swiss light source) took the
idea of the event/timing system from APS/ANL and designed his event
system for SLS, EVG/EVR-100 series. Later for Diamond light source
he designed the modules with newer technologies, EVG/EVR-200 series.
It should have much potential, and Jukka at MRF reported on the
possible embedded EPICS on RTEMS on PowerPC on EVG230. (We normally
don't use that PowerPC, yet.)
The event rate is around 100MHz depending on the rf frequency, we can
transfer 2kbyte of information at the rate of ~100MHz/2000, which is
fast and large enough for most applications to provide additional
beam information.
The system is used at Diamond and BEPCII at IHEP-Beijing. We hope to
utilize it at our running machine, KEK Linac, from the next summer.
It is also planned to be used or is evaluated at many places
including LCLS, LANL, Shanghai, SNS(?), BNL(?). The current
developer of the EPICS device support is Eric Bjorklund at LANL.
The jitter and the drift with this system are several of 10ps, and we
will keep some of the old but more precise system for some areas.
However, most of the signals will be replaced with outputs from this
system.
This week, we are evaluating the new device support from Eric on
VxWorks collaborating with people from IHEP, Ms. Lei and Mr. Xu.
Hopefully, the next week we will evaluate its new functionality soon,
and maybe with RTEMS as well. (Although we didn't succeeded in
building it on RTEMS.)
Regards.
>>> On Thu, 13 Dec 2007 11:52:30 JST, Andrew Johnson
<[email protected]> wrote;
> Frank Lenkszus wrote:
> > > > I took a quick look at the Micro-Research web site. I'm not
sure what > > the genesis of their event system is but it looks very
familiar and > > interesting. What I can tell you is Fermi Lab
published an event system > > several years ago. We at APS looked at
what they had done and developed > > what we considered a higher
performance system suitable for general > > timing at the APS in the
very early 90's. Our implementation added > > features such as
synchronized time stamping for record processing. > > Subsequently
SLS took the APS design, updated it and increased the speed > > by
~x10 while maintaining the programming model. I believe the SLS > >
version became commercially produced but I don't recall the firm name.
> > I'm not sure if they were the original, but Micro Research are
the > current suppliers, so this is the great**N grand-son of the APS
Event > System, versions of which have been used at various
accelerators around > the world since we gave away the design. EPICS
support is pretty much > guaranteed with any version.
> > - Andrew
> -- > When a distinguished but elderly scientist states that
something is
> possible, he is almost certainly right. When he states that something
> is impossible, he is very probably wrong. -- Arthur C. Clarke
-----
Kazuro FURUKAWA <[email protected]>
Linac&KEKB, High Energy Accelerator Research Organization (KEK), Japan
Telephone: +81-29-864-5200 x4316, Facsimile: +81-29-864-0321
--
Timo Korhonen PSI (Paul Scherrer Institut, http://www.psi.ch)
CH-5232 Villigen PSI
tel + 41- 56 3103262 fax + 41 - 56 310 3383
e-mail: [email protected]
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