EPICS Home

Experimental Physics and Industrial Control System


 
1994  1995  1996  1997  <19981999  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  1997  <19981999  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: record linking question
From: [email protected] (Ralph Lange)
To: [email protected] (EPICS Tech-Talk)
Date: Tue, 17 Mar 1998 14:16:27 +0100 (MET)
Benjamin Franksen wrote:
> Perhaps it is worth mentioning that the SCAN field is not PP, so if you
> change it over CA you need to process the record (eg by a put to the
> PROC field) for the change to take effect.

Which is IMO not true, as the SCAN field is special by nature, i.e. scan
periodic list issues are taken care of automatically by database runtime
access. [See base/src/db/dbAccess.c if you _really_ want to know the
details.]

SCAN fields are accessible, i.e. you may change it any way you like (CA or
DB links). Keep in mind that --- as SCAN is of a MENU type --- you will
have to use the index number instead of the string at runtime.

Within the database (part)

---------              ----------
|       |              |        |
|       |  PP          |        |
|    VAL|<-------------|INP     |
|       |              |        |
|       |              |        |
---------              ----------
recSrc                 recDest

if recSrc.SCAN is set to Passive, each processing of recDest will process
recSrc before the recSrc.VAL is used.

Setting recSrc.SCAN field to something different from Passive will disable
this mechanism. recSrc will be processed according to its SCAN value.
When processed, recDest will use whatever recSrc.VAL contains at that time.
No additional processing is required.

Ralph

Replies:
Re: record linking question Marty Kraimer
References:
Re: record linking question Benjamin Franksen

Navigate by Date:
Prev: Re: record linking question Benjamin Franksen
Next: Re: record linking question Marty Kraimer
Index: 1994  1995  1996  1997  <19981999  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: record linking question Benjamin Franksen
Next: Re: record linking question Marty Kraimer
Index: 1994  1995  1996  1997  <19981999  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