Argonne National Laboratory

Experimental Physics and
Industrial Control System

1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  <20122013  2014  2015  2016  2017  2018  2019  2020  Index 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  <20122013  2014  2015  2016  2017  2018  2019  2020 
<== Date ==> <== Thread ==>

Subject: Question about CA event (i.e. monitor) time order
From: Dirk Zimoch <dirk.zimoch@psi.ch>
To: EPICS <tech-talk@aps.anl.gov>
Date: Thu, 05 Jul 2012 17:21:55 +0200
Hello,

Consider a client that subscribes for two PVs (here in particular two fields of the same record). Now the IOC (the record support) posts events on both fields. Is the time order of these two events preserved?

In other words, are the monitor callbacks of the client called in the same order as the IOC calls db_post_events()?

In my particular case, I have a client (with unknown source code) that sometimes sees value changes on two fields of the motor record, DMOV and RRBV, in the wrong order. Thus in the DMOV callback, RRBV still has the old value. I checked in the motor record that DMOV is always posted after RRBV.

Is there any mechanism in EPICS that could swap the execution order or should the problem be searched in the client?

Dirk

Replies:
Re: Question about CA event (i.e. monitor) time order Andrew Johnson
Re: Question about CA event (i.e. monitor) time order Tim Mooney

Navigate by Date:
Prev: Re: 回复: Re: Re: Problems when download synApps IOC Dirk Zimoch
Next: Re: caQtDM: a MEDM replacement Michael Johnson
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  <20122013  2014  2015  2016  2017  2018  2019  2020 
Navigate by Thread:
Prev: Re: ImageJ from waveform record Steve Kinder
Next: Re: Question about CA event (i.e. monitor) time order Andrew Johnson
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  <20122013  2014  2015  2016  2017  2018  2019  2020 
ANJ, 18 Nov 2013 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·