Argonne National Laboratory

Experimental Physics and
Industrial Control System

1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  <20062007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  Index 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  <20062007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017 
<== Date ==> <== Thread ==>

Subject: Re: AlarmHandler - filtering vs. HYST
From: Randy Flood <flood@aps.anl.gov>
To: tech-talk@aps.anl.gov
Date: Mon, 17 Apr 2006 07:51:17 -0500


Terry Carlino wrote:



Operationally "Not Significant " is a situational term. If I have degrading vacuum, which hits a MINOR I want someone to look at it ONCE, to evaluate the need for intervention. What I don't need is for vacuum sitting at the MINOR setpoint to constantly alarm, as it goes above and below. Most would think that the likelihood of something like that happening with any regularity is small. When you have hundreds of vacuum pumps the regularity goes way up. What I really need is a way to disable just individual MINOR alarms while allowing the channel to still alarm on a MAJOR.

ALH provides this. You can either set the entire alarm handler or individual pv's to beep on severity. Individual groups or pv's are done from the Action menu list and the entire ALH from the Setup menu list




But in some cases I want users to get at least the initial flash, so conditions can be evaluated. Once I know there is a problem to be watched I only want to know if conditions deteriorate to the MAJOR condition.


You should look at the "NOACK Transient" mask in ALH. With this set, when
the PV goes out of alarm ALH will stop beeping at you.

Except when the value is hovering around the setpoint. HYST could be a reasonable to deal with this, provided you can get someone to decide what a reasonable value is for a couple of thousand different channels. A better way to deal with it is just to give the user the ability to disable MINOR alarms easily without affecting the MAJOR alarms, or having to go into the configuration tools.

The beep severity doesn't disable the alarm, it only changes when it beeps and you don't have to change the permanent configuration.



I certainly agree.


I also believe that alarm limits, especially MINOR alarms, should be
influenced by operational reality as well as engineering design.  If the
normal value of an analog input is close enough to an alarm limit to
generate alarms when no action is actually required, that limit should
probably be changed.

Based on personal experience I can state that any significant number of
"nuisance" alarms will lead to users becoming less reactive to real alarms.

One thing we've done at APS is to utilize $FORCEPV. If you are in a mode where you only care about major alarms (e.g. Conditioning power supplies), the $FORCEPV disables/modifies the alarm until that mode is over. It cuts down on nuisance alarms a lot.



We were having enough issues with operators silencing ALH "forever" (so
they wouldn't be annoyed by "false" alarms) that I modified ALH to put a
black border around the button on the screen so you could tell it was
silenced without opening the alarm window.

We have had similar problems in the past for the same reasons. A re-evaluation of the which parameters were monitored by the AH and of their setpoints has help fix this problem. Off loading alarms which were not operational driven also helped. (The trend is often to place non-operational alarms in the control room because the control room is always manned. Setting up AH which can page or email interested parties makes this mostly unnecessary.) We have eliminated many MINOR alarms and the situation is better than before.



-- Randy Flood Chief of Operations ASD Operations Group 630-252-1767 4-1767




References:
Re: AlarmHandler - filtering vs. HYST Brian McAllister
Re: AlarmHandler - filtering vs. HYST Terry Carlino

Navigate by Date:
Prev: Re: AlarmHandler - filtering vs. HYST Terry Carlino
Next: CAJ 1.0.4 issues Chu, Paul C.
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  <20062007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017 
Navigate by Thread:
Prev: Re: AlarmHandler - filtering vs. HYST Terry Carlino
Next: Alarm Handler in Global mode in and outside the control room Ernest L. Williams Jr.
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  <20062007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017 
ANJ, 02 Sep 2010 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·