EPICS Controls 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  2018  2019  2020  <20212022  2023  2024  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  2018  2019  2020  <20212022  2023  2024 
<== Date ==> <== Thread ==>

Subject: Re: [EXTERNAL] Archiver getDataAtTime and getData endpoints have a timestamp discrepancy
From: "Zimmermann, David Daniel via Tech-talk" <tech-talk at aps.anl.gov>
To: "De La Paz, Elena" <delapaz3 at llnl.gov>, "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov>
Date: Tue, 10 Aug 2021 14:48:48 +0000

Have you tried something like UNIXSECONDS FOR SECS OF VAL 3 + 1? There might be an issue of it using something like “<” rather than “<=”.

 

 

signature_61897647

David Zimmermann

Scientist, Controls Software

AOT-IC Accelerator Operations and Technology, Instrumentation and Controls

 

Office: 505.664.0824

Mobile: 503.547.5966

 

Los Alamos National Laboratory

lanl.gov

 

 

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of "De La Paz, Elena via Tech-talk" <tech-talk at aps.anl.gov>
Reply-To: "De La Paz, Elena" <delapaz3 at llnl.gov>
Date: Monday, August 9, 2021 at 3:35 PM
To: "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov>
Subject: [EXTERNAL] Archiver getDataAtTime and getData endpoints have a timestamp discrepancy

 

Hi all,

 

I have a question about using the different endpoints and the timestamp resolution of the archiver. Here is the situation that is confusing me:

 

  1. I make a request to the getData endpoint for some <PV> that returns multiple values, each accompanied by a secs and nanos field indicating when the value was updated

Example response for pv ID:  [{ val: “2”, secs: “1627576833”, nanos: “342322864”}, {val: “3”, secs: “1627576922”, nanos: “563728637”} ]

  1. When I make a request to getDataAtTime where the at parameter contains the full returned timestamp, down to the nanoseconds, I get the record value before:

Example request: <ARCHIVER DATA ENDPOINT>/getDataAtTime?at=<UNIXSECONDS FOR SECS OF VAL 3>.563728637 -d [“ID”]

Example response: { “ID”: “2”}

 

This occurs over shot intervals, so time zone issues are not the underlying cause. Is there some difference in the time resolution of the different endpoints? Is this a quirk of the archiver? We are doing a work around by rounding up to milliseconds, but it is confusing that the timestamp returned in nanoseconds can’t be used precisely in getdataattime

 

Thank you,  

 

Elena De La Paz

 


Navigate by Date:
Prev: RE: ADURL with Axis PTZ network camera Heesterman, Peter J via Tech-talk
Next: RE: Getting started talking to a device Leblanc, Gregory via Tech-talk
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  2018  2019  2020  <20212022  2023  2024 
Navigate by Thread:
Prev: Great Career Opportunity for Particle Accelerator Instrumentation Physicist/Engineer Nicholas James Meyler via Tech-talk
Next: HiPace control via EDU TC 400 Marco A. Barra Montevechi Filho via Tech-talk
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  2018  2019  2020  <20212022  2023  2024 
ANJ, 10 Aug 2021 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·