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

Subject: Re: how to know which PVs write to a PV
From: Ralph Lange <[email protected]>
To: EPICS Tech-Talk <[email protected]>
Date: Wed, 21 May 2014 11:16:38 +0200
On 21/05/2014 10:54, LEI Ge wrote:
> Hi, all,
>
> This week we met a problem, a PV's value should be 1 (to enable our e-gun trigger), but sometimes it becomes 0 unexpectedly. I checked the software logic I can remember to this pv, and have not found the reason. Maybe there is some logic I forget or I don't know, to write to this pv. So is there a way to check in our control system, which PVs write to this pv? Or, this PV is written from which IP?
>
> Thanks a lot ,
>
> Ge

Hello Ge,

There is a module to log all Channel Access Puts [1], which logs all
Channel Access put operations to an iocLogServer, and should tell you if
the PV has been changed from the outside.

DB writes from the same IOC are harder to log. You can always try to set
the TPRO field of the target record. This will show you when it is being
processed, and by which thread, but not exactly which other record is
writing. (You should be able to find this by searching the IOC's
database, though.)

Writes from records on other IOCs are done through Channel Access, and
logged by CAPutLog.

Good luck,
~Ralph

[1] http://www-csr.bessy.de/control/SoftDist/caPutLog/

Replies:
RE: how to know which PVs write to a PV Hu, Yong
Re: Re: how to know which PVs write to a PV LEI Ge
References:
how to know which PVs write to a PV LEI Ge

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