Experimental Physics and
Industrial Control System

Richard Farnsworth <[email protected]> · Tue, 28 Sep 2010 09:14:52 +1000

> Nevertheless, multicasting will probably be easier to configure, and more importantly for your users
> to understand, if one doesnât object to enabling multicasting in his control system routers. Many
> sites already make this concession for at least some of their Allen Bradley PLCs, as I recall.

We at the Australian Synchrotron have this latest issue alluded to by Jeff  - that is multicasting is enabled for our PLC's (Schneider Modicon Premiums). At first it was tolerable, but lately, with increasing network traffic it's becoming a serious problem and has started to affect other equipment - Most notably the timing system control. Our solution will involve second network cards for some PLC's and the separation of PLC networks.

Cheers

Richard Farnsworth | Head of Computing | Australian Synchrotron

Please Note: From 13th October 2010 I shall be no longer employed by the Australian Synchrotron. If you wish to communicate personnally after that date please use [email protected], or wait for my first post with an APS email address.

----

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Jeff Hill
Sent: Tuesday, 28 September 2010 8:00 AM
To: 'Andrew Johnson'; [email protected]
Subject: RE: Soft IOCs and Port Numbers

> Do you have to configure CA clients running on a
> machine with multiple interfaces to only use one
> of them for broadcasts, or would CA take care of
> that for you if they're all in the same subnet?

The default is for CA to broadcast on all active
LAN interfaces it finds, and unicast on all
active point-to-point interfaces it finds.

I suppose that a new environment variable perhaps
named EPICS_CA_SUBNET_LIST might make configuring
broadcasts for all interfaces attached to one or
more subnets easier.

Nevertheless, multicasting will probably be easier
to configure, and more importantly for your users
to understand, if one doesnât object to enabling
multicasting in his control system routers. Many
sites already make this concession for at least some
of their Allen Bradley PLCs, as I recall.

Jeff
______________________________________________________
Jeffrey O. Hill           Email        [email protected]
LANL MS H820              Voice        505 665 1831
Los Alamos NM 87545 USA   FAX          505 665 5107

Message content: TSPA

> -----Original Message-----
> From: [email protected] [mailto:tech-talk-
> [email protected]] On Behalf Of Andrew Johnson
> Sent: Friday, September 24, 2010 11:10 AM
> To: [email protected]
> Subject: Re: Soft IOCs and Port Numbers
>
> On Friday 24 September 2010 11:24:42 Ralph Lange wrote:
> >   On 24.09.2010 12:16, Eric Norum wrote:
> > > Or run every IOC in it's own virtual machine?
> >
> > Have been investigating that- too thick. Running a VM only to have an
> > additional IP address .... nah.
> >
> > I would prefer the solution that uses virtual network interfaces on
> the
> > soft IOC host. Relatively slim, completely transparent, does not need
> > additional services.
>
> But it does require configuring a alias interface and providing an IP
> address
> for each soft IOC you want to run.  If you're using non-routable
> addresses the
> extra IPs may not be a major issue (as long as your subnets were made
> large
> enough), but it might mean getting IT involved every time Controls
> wants to
> add a new soft IOC.  Do you have to configure CA clients running on a
> machine
> with multiple interfaces to only use one of them for broadcasts, or
> would CA
> take care of that for you if they're all in the same subnet?
>
> A machine-specific name-server would be more efficient since each PV
> name
> request only has to be checked once by the name-server rather than by
> all of
> the IOCs on the machine.
>
> - Andrew
> --
> The best FOSS code is written to be read by other humans -- Harald
> Welte

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System