RE: Controlling vacuum valves with EPICS

[Mark Rivers <rivers@cars.uchicago.edu>]

Hi Florian,

We use PLCs to control our valves because they are part of an Equipment Protection System (EPS).  If the vacuum goes bad somewhere the PLC automatically closes the appropriate valves.  EPICS makes valve open/close requests to the PLC, and the PLC acts on those requests only if is safe to do so.

If you don't have any EPS requirements, i.e. it is fine to open/close the valves any time, then using EPICS to directly control them should be fine.  But if you do need an EPS I would use a PLC for that, not EPICS, since it might not be running when you need it.

Mark

________________________________________
From: tech-talk-bounces@aps.anl.gov [tech-talk-bounces@aps.anl.gov] on behalf of Florian Feldbauer [florian@ep1.ruhr-uni-bochum.de]
Sent: Tuesday, April 05, 2016 2:52 AM
To: EPICS Tech-Talk
Subject: Controlling vacuum valves with EPICS

Hey all,

I'm working with EPICS now for several years to develop parts of the
Detector Control System for
the PANDA experiment.
For our luminosity detector we need to control a small vacuum system.
I had a look at various talks from EPICS meetings to see, how others are
building their control systems
and I have a question concerning this:
All the systems I have seen are using PLCs to control the valves of the
system.

What is the advantage of a PLC for controlling the valves?
Why not using an EPICS IOC for direct control running on a realtime system?

I never worked on vacuum systems before, and our vacuum workshop here at
Mainz
could not help me with this question.

Many thanks in advance for the help!

   Florian

--
----------------------------------------
| Dr. Florian Feldbauer                |
|                                      |
| Helmholtz-Institut Mainz /           |
| Johannes Gutenberg-Universität Mainz |
| Johann-Joachim-Becher-Weg 36         |
| D-55128 Mainz                        |
|                                      |
| Office: SB1 / 00-213                 |
| Phone:  (+49)6131 / 39-29608         |
----------------------------------------