EPICS Controls Argonne National Laboratory

Experimental Physics and
Industrial Control System

1994  1995  1996  <19971998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024  Index 1994  1995  1996  <19971998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
<== Date ==> <== Thread ==>

Subject: Re: Bad CALC record kills IOC
From: Andrew Johnson <[email protected]>
To: Bob Dalesio <[email protected]>
Cc: [email protected]
Date: Fri, 04 Jul 1997 10:25:10 +0100
Bob Dalesio wrote:
> 
> Ron Chestnut at SLAC reported that the following record caused the
> scan task to crash. I assume that the watchdog restarted the task and
> left this record locked - but I don't know. The changes he made to fix
> it were worrisome - that is - they did not seem significant. I
> will take a look at this - unless someone beats me to it.

> BAD:
> 
> grecord(calc,"$(Ring):BXBCM:TEMPA") {
>         field(SCAN,"10 second")
>         field(CALC,"( (A&C) >> 3 ) - B")
>         field(INPA,"$(Ring):BXBCM:TEMP.VAL  PP MS")
>         field(INPB,"273.")
>         field(INPC,"65535")
> }
> 
> GOOD:
> 
> grecord(calc,"$(Ring):BXBCM:TEMPA") {
>         field(SCAN,"10 second")
>         field(CALC,"((A&C)>>D)-B")
>         field(INPA,"$(Ring):BXBCM:TEMP.VAL  PP MS")
>         field(INPB,"273.")
>         field(INPC,"65535")
>         field(INPD,"3")
> }

The thing which I see as significant in these differences is that Ron
has taken the literal "3" out of the expression and put it into the
input D instead.  I have been aware for some time that literals aren't
always accepted in CALC expressions (but some work fine -- thats the
wierd thing about it).  I suspect this may be the area of the problem,
but I'm only guessing.  It may relate to a literal with an adjacent
space, which matches where Rozelle's saw the error being reported.

-- Andrew
   ___
 .'   `.	Andrew Johnson, Head of Electronics
/ Royal )	Royal Greenwich Observatory
\ Greenwich	Madingley Road, Cambridge, CB3 0EZ
| Observatory	Tel: +44 1223 374823   Fax: 374700
+----------	WWW: http://www.ast.cam.ac.uk/~anj

References:
Re: Bad CALC record kills IOC Bob Dalesio

Navigate by Date:
Prev: Re: Bad CALC record kills IOC Rozelle Wright
Next: Re: Bad CALC record kills IOC Ralph Lange
Index: 1994  1995  1996  <19971998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
Navigate by Thread:
Prev: Re: Bad CALC record kills IOC Bob Dalesio
Next: Re: Bad CALC record kills IOC Rozelle Wright
Index: 1994  1995  1996  <19971998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
ANJ, 10 Aug 2010 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·