Experimental Physics and
Industrial Control System

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<== Date ==>		<== Thread ==>

Subject:	Re: PV Seq not process everytime
From:	"Hu, Yong via Tech-talk" <tech-talk at aps.anl.gov>
To:	GAGET Alexis <alexis.gaget at cea.fr>, Ralph Lange <ralph.lange at gmx.de>, "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov>
Date:	Thu, 10 Feb 2022 14:46:02 +0000

Hi Alexis,

I guess your “mySetPoint” and “myCommand” might be asynchronous records, meaning it probably takes one or a few seconds to be completely processed.

If that is the case, you’d better to use CA instead of PP in LNK*, something like this: field(LNK1,"mySetPoint CA"). If “mySetPoint” does not take its value from “myPV1”, you probably should use something like this: field(LNK1,"mySetPoint.PROC CA"). The same rule for LNK2, either field(LNK2,"myCommand CA") or field(LNK2,"myCommand.PROC CA")

Additionally set mySetPoint.TPRO and myCommand.TPRO to 1. Also, check if there are other records or programs which write (or caput) to “mySetPoint” and “myCommand”.

If this problem happens again, type this command although I am not sure if it is really helpful: caget mySetPoint.LCNT myCommand.LCNT

Cheers,

~Yong

Obsolete EPICS Wiki: https://wiki-ext.aps.anl.gov/epics/index.php?title=RRM_3-14_dbCommon

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov>
Reply-To: GAGET Alexis <alexis.gaget at cea.fr>
Date: Thursday, February 10, 2022 at 3:00 AM
To: Ralph Lange <ralph.lange at gmx.de>, "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov>
Subject: RE: PV Seq not process everytime

Hi Ralph,

Thanks for your suggestion (and answering the CEA team all the day yesterday ;) )

Sorry I forgot to mention that i had tested the FLNK before (without the CP), the CP was my second solution to test if it was the problem.

MDEL of myPV1 is at 0...I've tried -1 yesterday just in case, doesn't change anything.

the problem is I wasn't able to reproduce the problem yesterday, except at the end of the day when beam started I have to find the causality of this correlation .... In the meantime I've noticed that when I'm processing myPV1, by reintroducing value in CSS, it process correctly the sequence, but get stuck few step later, BUT if I execute a dbtr of mySequence it seems to correct the problem until the next reboot of the IOC.

Any idea ?

De : Tech-talk <tech-talk-bounces at aps.anl.gov> de la part de Ralph Lange via Tech-talk <tech-talk at aps.anl.gov>
Envoyé : mercredi 9 février 2022 10:51:18
À : EPICS Tech Talk
Objet : Re: PV Seq not process everytime

On Wed, 9 Feb 2022 at 09:02, GAGET Alexis via Tech-talk <tech-talk at aps.anl.gov> wrote:

record(ao, "myPV1"){

}

record(seq,"mySequence"){

     field(DLY1,"0")

     field(DOL1,"myPV1 CP")

     field(LNK1,"mySetPoint PP")

     field(DLY2,"0.5")

     field(DOL2,"1")

     field(LNK2,"myCommand PP")

}

myPV1 is the destination i want to reach, each time I change it, it process this sequence to set the destination in mySetPoint, and 0.5s later to activate the command. It works well most of the time. But yesterday sometimes, myPV1 was changed but mySequence was not processed .... it causes the whole sequence (emittance measurement) to get stuck. It can be unstuck by processing "mySequence" but it's a long sequence and we don't stay in front of the computer.

Hi Alexis,

CP input links are using monitors. If you have a myPV1.MDEL setting, it could suppress changes to be sent to mySequence.

Unless you have a specific reason to use a CP inlink, you could also set myPV1.FLNK to point to mySequence. That would make this a very tight coupling, with the sequence being run basically as part of changing myPV1. (Remove the CP in mySequence.DOL1 in that case.)

Cheers,
~Ralph

Replies:: Re: PV Seq not process everytime Hu, Yong via Tech-talk

References:: PV Seq not process everytime GAGET Alexis via Tech-talk; Re: PV Seq not process everytime Ralph Lange via Tech-talk; RE: PV Seq not process everytime GAGET Alexis via Tech-talk

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ANJ, 14 Sep 2022

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System