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  2012  2013  2014  2015  2016  <2017 Index 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  <2017
<== Date ==> <== Thread ==>

Subject: CA monitoring weirdness for status/severity
From: "Hogben, Colin H" <Colin.Hogben@ukaea.uk>
To: "tech-talk@aps.anl.gov" <tech-talk@aps.anl.gov>
Date: Mon, 07 Aug 2017 10:58:32 +0100
Hi,
Here at JET, I'm developing bridges (both directions) between EPICS Channel Access and our home-grown Object Monitoring System. I've come across what to me seems like unexpected behaviour, which I can demonstrate with standard CA tools.

First I start softIoc with the following database:

  record(ao, "chah:ao") {
    field(HIGH, 10)
  }

Next, I monitor the HIGH field:

  gen-pub-11:~ $ camonitor chah:ao.HIGH
  chah:ao.HIGH                   <undefined> 10 UDF INVALID

My first surprise is that the HIGH field is reported as undefined, when it clearly has the value I configured. But it gets weirder. I now do a

  caput chah:ao.HIGH 11

and the camonitor spits out an update:

  chah:ao.HIGH                   <undefined> 11 UDF INVALID

However, if I start a new camonitor, I get

  gen-pub-11:~ $ camonitor chah:ao.HIGH
  chah:ao.HIGH                   2017-08-07 10:30:55.033976 11

So is it undefined or not? I find it surprising that the last output from camonitor should differ depending on when I start it.

Any illumination welcome!
--
Colin Hogben
Professional Software/Control Engineer
CODAS & IT Department
United Kingdom Atomic Energy Authority
Culham Science Centre
Abingdon
Oxfordshire
OX14 3DB
Tel : 01235 464948
Web: www.gov.uk/ukaea

Replies:
Re: CA monitoring weirdness for status/severity Johnson, Andrew N.

Navigate by Date:
Prev: RE: Compile Warning:"Device using undefined record type 'stringin', place-holder created Mark Rivers
Next: Re: CA monitoring weirdness for status/severity Johnson, Andrew N.
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  <2017
Navigate by Thread:
Prev: RE: Compile Warning:"Device using undefined record type 'stringin', place-holder created Mark Rivers
Next: Re: CA monitoring weirdness for status/severity Johnson, Andrew N.
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  <2017
ANJ, 07 Aug 2017 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·