Experimental Physics and
Industrial Control System

Emmanuel Mayssat <[email protected]> · Fri, 24 Aug 2007 15:52:44 -0700

Yes, it is plug and play.
But let's imagine that now you do this for all of your devices
(chillers, modulators, x-ray detectors...). Let's take the example of a
chiller.

A chiller usually comes with a serial or Ethernet interface. A computer
is not included (contrary to detectors;). So you add one (let's call it
a picotux computer http://en.wikipedia.org/wiki/Picotux or a gumstix).
You install epics and chiller driver on computer stick. As you do so
your chiller has just become "plug-and-play".

Now, let's create a *generic* chiller interface. So PV are
TemperatureSetPointAO
ReadBackTemperatureSetPointAI
CurrentWaterTemperatureAI
AlarmMBBI

Once connected to network all of those PVs are available.

Now I decide to change the chiller from a Schreiber to a Polyscience
(or change detector from a Roger to a Mar). Because both of the chillers
have the generic interface the control system does not perceive the
change. So no compilation, database changes are needed. No need of a
computer engineer either (he programmed the computer prior chiller
installation). In other words, only a technician is required...

To me, it appears to be an interesting design because contrary to most
of you, I have several identical sites to maintain. Plus most of those
sites are at remote locations (+ I need permission from 3rd party for
remote access). Also, at remote sites hardware may be slightly different
but software has to be the same.

Now if you push this design to the limit, where all epics controlled
device are "plug-and-play" , then it seems that your high level software
(extensions) are immune to hardware changes.
The ioc that is on the device could be seen as a software patch to the
control system.

As anybody considered such a design, were you turn all of your devices
into EPICS embedded ones?

--
E

On Fri, 2007-08-24 at 13:40 -0500, Mark Rivers wrote:
> I'm not quite sure I know what you mean, but I think we are doing what
> you are suggesting.  We have, for example, x-ray detectors (MAR, Roper)
> that have an EPICS soft IOC running on the Linux or Windows computer
> that controls the detector.  When we turn on the detector and its soft
> IOC boots we can then control the detector from other IOCs that run the
> rest of the beamline.  Is that plug and play?
> 
> Mark
> 
> 
> > -----Original Message-----
> > From: [email protected] 
> > [mailto:[email protected]] On Behalf Of Emmanuel Mayssat
> > Sent: Friday, August 24, 2007 1:14 PM
> > To: epics
> > Subject: Network plug and play epics devices
> > 
> > Hello all,
> > 
> > In though, I have been tinkering with a network plug-and-play epics
> > devices. Let's imaging that you have a new device you want to control
> > through EPICS. You connect it, power it, and allow for network
> > communication. 
> > Now in practice, the device is not under epics control yet. 
> > But what if the device includes an embedded computer with the 
> > associated
> > epics ioc? Then when you plug it to the network, the PV are 
> > immediately
> > available...
> > 
> > Is anybody using such a design?
> > 
> > --
> > Emmanuel
> > 
> > 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System