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<== Date ==> <== Thread ==>
Subject: RE: [EXTERNAL] Re: How to archive PVs regularly even if they are not updating
From: Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>
To: Ralph Lange <ralph.lange at gmx.de>
Cc: "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov>
Date: Mon, 26 Sep 2022 16:17:00 +0000

Hi Ralph,

 

Ø  For rarely-moving things, it just blows up the file with redundant identical samples.

 

That is not my interpretation of what Kay said:

Ø  Instead, it would for example scan once every 5 minutes, and then write whatever the most recently received sample was .. if it changed.

 

That means it should not fill up the file, because it does not write anything if it has not changed.

 

Mark

 

 

 

 

From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Ralph Lange via Tech-talk
Sent: Monday, September 26, 2022 10:47 AM
To: EPICS Tech Talk <tech-talk at aps.anl.gov>
Subject: Re: [EXTERNAL] Re: How to archive PVs regularly even if they are not updating

 

On Mon, 26 Sept 2022 at 17:13, Kasemir, Kay <kasemirk at ornl.gov> wrote:

MONITOR:  Channel uses monitor (for ADEL threshold) and tries to save every received value.

SCAN:  Channel uses monitor (for ADEL threshold) and then saves the most recently received value every SCAN period.

 

SCAN does not perform a get or get-callback every SCAN period, and it also doesn't save the time of when it was scanned.

Instead, it would for example scan once every 5 minutes, and then write whatever the most recently received sample was .. if it changed.

 

Pardon my archiver ignorance and thanks for the explanation.

Of course: SCAN mode intends to limit the number of samples written to file for fast-moving things with small ADEL. For rarely-moving things, it just blows up the file with redundant identical samples.

 

Sorry for the noise.

~Ralph

Replies:
Re: [EXTERNAL] Re: How to archive PVs regularly even if they are not updating Ralph Lange via Tech-talk
References:
Re: How to archive PVs regularly even if they are not updating Shankar, Murali via Tech-talk
Re: How to archive PVs regularly even if they are not updating Ralph Lange via Tech-talk
Re: [EXTERNAL] Re: How to archive PVs regularly even if they are not updating Kasemir, Kay via Tech-talk
Re: [EXTERNAL] Re: How to archive PVs regularly even if they are not updating Ralph Lange via Tech-talk
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