Rod,
I was involved with a such a systems (and we needed to address that very concern that our regulator had).
The two places where the alarm goes off Is in the field and in the control room.
One could argue that the alarm going off in the field plays a safety role if it is purpose is to direct staff to leave the area. Redundant and diverse solutions using both horns and lights would be a nice way of handling it. There are
some pretty nifty IEC 61508 certified monitors and horns on the market. Personal preference I would try to do that one independently of EPICS as the hazard and risk analysis is simplified.
One could potentially argue the annunciation in the control room is not safety critical but safety related. The safety issue is resolved if the local horn is going and staff have left the area. Generally I would use a separate app with
watchdogs etc. I am aware of one lab with the regulator required that app to be running as a condition of operating the machine.
I think it comes down to how you do the Hazard and Risk Analysis and the mitigation you have in place.
Elder Matias
Mighty Oaks
http://www.mightyoaks.com
----------------------
Hi Rod,
Background noises and alarm floods are also potential problems, so if alarms are really important, audio needs to be supplemented with visual alarms (i.e., a multi-factor
approach needs to be considered). Relying on audio alarms alone is probably not going to be satisfactory because someone is always going to be adjusting something to suit individual preferences. Are you doing any alarm filtering?
John Munro
ORNL
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Rod Nussbaumer
Sent: Wednesday, January 14, 2015 4:27 PM
To: epics Techtalk
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.
Elder Matias,
BSc,
CEO
T: 250.386.9398 x203 | [email protected]
MIGHTY OAKS Business ~ IT ~ Community
27 Burnside Road West Victoria | TF: 866.386.9398 | www.mightyoaks.com