Re: question about pvmonitor behavior

[Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>]

You need to add the PP attribute to the OUT field if you want myaipv to process.  Otherwise it writes the value, but does not process the record, so no monitor is posted.

  field(OUT, "myaipv PP")

Mark

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Alfio Rizzo via Tech-talk <tech-talk at aps.anl.gov>
Sent: Tuesday, March 17, 2026 5:27 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: question about pvmonitor behavior

 

Hej

I noticed that the pvmonitor of a record value does not update  when the .VAL is  changed from the  OUT field of another record,

E.g. Using this simple db

record(ai, "myaipv"){
   field(PINI, "YES")
   field(VAL, 100)
}

record(ao, "myaopv") {
   field(PINI, "YES")
   field(VAL, 30)
   field(OUT, "myaipv")  
}

If I do pvput myaovpv 1000, the myaipv.VAL is updated correctly (pvget myaipv gives back the updated value)

But this change is not shown in the pvmonitor  STDOUT

According to what I heard this is the intended behavior, but why apparently it applies only to  the .VAL field ?

I have tested the OUT with other fields like the alarm fields, or .RVAL , etc (i.e. OUT, "myaipv.HIHI") (OUT, "myaipv.RVAL")

Then if I do pvmonitor myaipv.HIHI for instance, everytime the myaopv value changes, 

The pvmonitor reacts as well showing the updated .HIHI field value

Can someone give some more explanation about ?

I am using EPICS 7.0.9/6.0.0

Thanks

Best

Alfio 

 

______________________

 

Alfio Rizzo

PhD / Automation Section Leader / ICS HW&I Group

 

European Spallation Source ERIC

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E-mail: alfio.rizzo at ess.eu

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