Even Yokogawa's PLC can run PREEMPT_RT version of Linux. Many of
you saw the demonstration of the realtime response of such PLC at
ICALEPCS09 at Kobe. The response time thru EPICS was less than
150 microsecond for several hours of the demonstration. It was
impressive for 533MHz PowerPC. Faster Intel CPU may provide
several-times better performance.
>>> On Thu, 17 Dec 2009 12:45:32 JST, David Kline <email@example.com> wrote;
> at aps, the ebricks are using a standard linux kernel (2.6.19) (vector
> linux distribution) with a real-time
> patch provided by the osadl group (http://www.osadl.org) ... *all free*
> ... we are happy with it and
> has made a difference with respect to interrupt response time.
> firstname.lastname@example.org wrote:
> > Hi,
> > I've noticed several people mentioning real time linux. Are proprietary
> > real time builds widely used, or is standard free linux with real time
> > patches generally used?
> > Are there hardware platforms that are more suitable for RT linux?
> > (specific CPUs or chipsets?)
> > Cheers,
> > Matthew
> > -----Original Message-----
> > From: email@example.com
> > [mailto:firstname.lastname@example.org] On Behalf Of Richard Farnsworth
> > Sent: 17 December 2009 00:34
> > To: Rees, Nick (DLSLtd,RAL,DIA)
> > Cc: email@example.com
> > Subject: RE: Remote I/O
> > Nick,
> > At the Australian synchrotron, we use Ethernet as a field bus also.
> > Ethernet is not deterministic in theory , but with clever networking you
> > can get around most of the issues in practice. We separate the
> > accelerator networks from the beamlines (and other places). We use
> > gateways if we need data transfer.
> > Our primary PLC's use Modicon premium PLCs (Schneider) and a Modbus/IP
> > driver (Not Mark Rivers one though, although it may have a common
> > ancestor). Also our PILZ safety system PLC's, and a number of other
> > systems use Modbus. We do have some other Ethernet drivers for a few
> > variant PLC's (Siemens and Rockwell and our building systems).
> > One problem we are getting into is that the keep alive chatter
> > (Broadcast) on the PLC's is starting to impact network performance and
> > we may look at separate networks (And second network cards) on certain
> > PLC's in the future.
> > Our IOC's talk via Moxa's terminal servers to serial devices, RS232
> > primarily, but also RS422 and RS485. We also have a number of Cosylab
> > supplied PC/104 soft IOC's with RS485 daughter cards.
> > Almost no VME, most analog and digital I/O is performed using PCI I/O
> > cards on a mixture of Soft IOC's and some running Redhawk real time
> > Linux. We will be removing them in the near future and just using
> > standard Linux.
> > Temperature measurements are done in part using a tiny (cheap) Modbus
> > device called an "ITM". More details if you need that. We recently
> > replaced most of them as they (ironically) got too hot wher we mounted
> > them and they failed.
> > VME (as a power supply/crate) is only in use on the timing system and
> > one or two special devices. We use Linux IOC's and a Struck VME to PCI
> > bridge for the odd VME only case.
> > I'd like to say no VxWorks, but I've discovered recently that the
> > Modicon premiums actually use VxWorks internally.
> > A strong emphasis on Linux throughout, the major exceptions being our
> > PLC development tools and the Dipole power supply uses (Ahhchoo, Spit,
> > Ting) Windows CE. Even our GUI's use wine on Linux to run the windows
> > executables we develop with Borland Delphi (We will change to QT over
> > time).
> > Richard Farnsworth | Head of Computing | Australian Synchrotron
> > p: (03) 8540 4118 | f: (03) 8540 4200 | m: 0421 082 147
> > firstname.lastname@example.org | www.synchrotron.org.au 800
> > Blackburn Road, Clayton, Victoria 3168
> > <br>This message and any attachments may contain proprietary or
> > confidential information. If you are not the intended recipient or you
> > received the message in error, you must not use, copy or distribute the
> > message. Please notify the sender immediately and destroy the original
> > message. Thank you.
> David M. Kline email@example.com
> Argonne National Laboratory
> Argonne IL, 60439 630.252.8639
> Advanced Photon Source, X-ray Science Division
> Optics and Detectors Group
Kazuro FURUKAWA <firstname.lastname@example.org>
Linac&KEKB, High Energy Accelerator Research Organization (KEK), Japan
Telephone: +81-29-864-5200 x4316, Facsimile: +81-29-864-0321
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