Experimental Physics and
Industrial Control System

Rod Nussbaumer <[email protected]> · Fri, 23 Jan 2015 09:45:29 -0800

Thanks for all of your comments.

While my original question was about the use of the 'old ALH'

application on a PC (running Linux, which I don't think I originally

mentioned) in a control room setting only, I appreciate the comments

from others regarding other alarm annunciation techniques. Those

comments will be sure to generate some dialog here, as well.

My present strategy under initial investigation is to use USB speakers.

In that scenario, I think we can use the console PC host to control the

volume via a 'hidden' tool making inadvertent volume adjustment much

less likely. It certainly appears that we can monitor the volume, and

also monitor the connection status of the speakers through software.

Power is supplied to the speakers through the USB interface, so that

eliminates the possibility of (hidden/silent) power source faults. This

should allow us to have a secondary alarm handler somewhere, which is

dedicated to monitoring the primary alarm handler.

For the record, we are using the ALH application now and in the

immediate future, however this is expected to change at some time not

too distant from now. The control room console that runs the ALH

application is pretty much dedicated to that purpose. Personnel safety

is managed independently from the control system here, and radiation

alarms & oxygen deficiency alarms use industrial alarm annunciators that

are not part of the primary control system, other than supervisory monitors.

   ---   rod.

On 01/20/2015 03:59 PM, Maren Purves wrote:

ALH or something else, sensors can fail too, it doesn't have to
have anything to do with what you're running or what you're
running it on. We recently had an almost whole system shutdown
(thankfully the instruments stayed cold) when the UPS failed
to last through a power outage.

The old ALH works quite well :)

Maren

On 01/20/15 13:43, Emmanuel Mayssat wrote:

Interesting thread.
If I understand your email correctly, you are using the old ALH on a PC.
Well, if you are sticking with this setup then the best way may be to
dedicate a computer to run the ALH
and put it behind a glass so that no one can touch it! Put the speakers
out of reach as well.

Are you open to using something else other than the ALH?

--
Emmanuel Mayssat
http://www.epicsqt.org

> Date: Wed, 14 Jan 2015 13:27:14 -0800
> From: [email protected]
> To: [email protected]
> Subject: Alarm annunciation with ALH and other PC based systems
>
> Hi All:
>
> Sorry that this isn't really an EPICS question, other than the tenuous
> connection via Alarm Handler.
>
> The question has been raised here about how to ensure that the audible
> alarms from Alarm Handler are always audible. A number of places exist
> where this can be disabled. The speakers can become faulty, the
> wall-wart commonly used to power the speakers can become
disconnected or
> faulty, the volume control on the speakers can be turned down, the host
> OS software controls can be turned down or muted either through
accident
> or software fault, audio cables can become faulty, and sound card
> hardware can become faulty. Most of these will manifest only in
silence.
>
> Has anyone undertaken measures to monitor any of these components in
> some way, or implemented hardware which is not subject to the common
> frailties of commodity audio equipment used for control room alarms?
>
> Any suggestions cheerfully accepted. Thanks.
>
> Rod Nussbaumer
> E-Linac Controls, TRIUMF
> Vancouver, Canada.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System