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 2021 <2022> 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 2021 <2022> 2023 2024
<== Date ==>		<== Thread ==>

Subject:	Re: Timing in seq record
From:	Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>
To:	Freddie Akeroyd - STFC UKRI <freddie.akeroyd at stfc.ac.uk>
Cc:	"tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov>
Date:	Thu, 3 Mar 2022 02:36:59 +0000

Hi Freddie,

Thanks for pointing out that issue.

That issue was closed on March 12, 2021, saying there has been a pull request.

7.0.6 was release on July 3, 2021, and 7.0.6.1 on October 6, 2021. But I don't see anything about this issue in the release notes for either of these.

Is there a release of base that fixes this fairly serious issue?

Mark

From: Freddie Akeroyd - STFC UKRI <freddie.akeroyd at stfc.ac.uk>
Sent: Wednesday, March 2, 2022 7:54 PM
To: Mark Rivers <rivers at cars.uchicago.edu>
Subject: RE: Timing in seq record

Hi Mark,

This might be related to Timers expire early · Issue #106 · epics-base/epics-base (github.com) as I think it may use timers for the delay

Freddie

From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Mark Rivers via Tech-talk
Sent: 03 March 2022 00:35
To: Mark Rivers <rivers at cars.uchicago.edu>
Cc: tech-talk at aps.anl.gov
Subject: RE: Timing in seq record

I see the same thing with base 7.0.5.

From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of Mark Rivers via Tech-talk
Sent: Wednesday, March 2, 2022 6:31 PM
To: tech-talk at aps.anl.gov
Subject: Timing in seq record

I have the following simple database with a seq record which just writes 1 and 0 to the Shutter record. There is a delay of $(DELAY) before writing 1 and before writing 0.

record(seq,"$(P)OpenCloseShutter") {

field(PINI, "YES")

field(DLY0,"$(DELAY)")

field(DOL0,"1")

field(LNK0,"$(P)Shutter PP MS")

field(DLY1,"$(DELAY)")

field(DOL1,"0")

field(LNK1,"$(P)Shutter PP MS")

field(FLNK,"$(P)OpenCloseShutter.PROC CA")

}

record(bo, "$(P)Shutter") {

field(ZNAM, "Done")

field(ONAM, "Moving")

}

If DELAY is 0.1 I see the following with camonitor on Shutter:

Test:Shutter 2022-03-02 18:22:24.997849 Moving

Test:Shutter 2022-03-02 18:22:25.092984 Done

Test:Shutter 2022-03-02 18:22:25.188102 Moving

Test:Shutter 2022-03-02 18:22:25.283205 Done

Test:Shutter 2022-03-02 18:22:25.378332 Moving

Test:Shutter 2022-03-02 18:22:25.473436 Done

Test:Shutter 2022-03-02 18:22:25.568547 Moving

Test:Shutter 2022-03-02 18:22:25.663681 Done

Test:Shutter 2022-03-02 18:22:25.758885 Moving

Test:Shutter 2022-03-02 18:22:25.854026 Done

Test:Shutter 2022-03-02 18:22:25.949228 Moving

The period is about 190 ms rather than the expected 200 ms, but not too far off.

However, if I set DELAY=0.01 then I see this:

Test:Shutter 2022-03-02 18:25:44.341923 Done

Test:Shutter 2022-03-02 18:25:44.347055 Moving

Test:Shutter 2022-03-02 18:25:44.352186 Done

Test:Shutter 2022-03-02 18:25:44.357367 Moving

Test:Shutter 2022-03-02 18:25:44.362523 Done

Test:Shutter 2022-03-02 18:25:44.367682 Moving

Test:Shutter 2022-03-02 18:25:44.372816 Done

Test:Shutter 2022-03-02 18:25:44.377965 Moving

Test:Shutter 2022-03-02 18:25:44.383104 Done

Test:Shutter 2022-03-02 18:25:44.388263 Moving

Test:Shutter 2022-03-02 18:25:44.393372 Done

Test:Shutter 2022-03-02 18:25:44.398496 Moving

Test:Shutter 2022-03-02 18:25:44.403633 Done

The period is 10 ms when it should be 20 ms. The DELAY appears to be 5 ms, not 10 ms.

If I set DELAY=.005 then the Shutter PV has no monitor events.

Something seems wrong here, since I know that epicsThreadSleep on Linux is capable of good accuracy down to 100 microseconds or so.

This is base 7.0.4 on Centos 7. Is this expected?

Mark

This email and any attachments are intended solely for the use of the named recipients. If you are not the intended recipient you must not use, disclose, copy or distribute this email or any of its attachments and should notify the sender immediately and delete this email from your system. UK Research and Innovation (UKRI) has taken every reasonable precaution to minimise risk of this email or any attachments containing viruses or malware but the recipient should carry out its own virus and malware checks before opening the attachments. UKRI does not accept any liability for any losses or damages which the recipient may sustain due to presence of any viruses.

Replies:: Re: Timing in seq record Johnson, Andrew N. via Tech-talk

References:: Timing in seq record Mark Rivers via Tech-talk; RE: Timing in seq record Mark Rivers via Tech-talk

Navigate by Date:: Prev: Re: StreamDevice Mark Rivers via Tech-talk; Next: Re: Timing in seq record Johnson, Andrew N. 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 2021 <2022> 2023 2024
Navigate by Thread:: Prev: RE: Timing in seq record Mark Rivers via Tech-talk; Next: Re: Timing in seq record Johnson, Andrew N. 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 2021 <2022> 2023 2024

ANJ, 14 Sep 2022

· Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System