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Subject: Re: Monitors on a stringin record
From: Marty Kraimer <[email protected]>
To: Ralph Lange <[email protected]>
Cc: Mark Rivers <[email protected]>, EPICS Tech-Talk <[email protected]>
Date: Fri, 11 Dec 1998 09:02:59 -0600
Ralph Lange wrote:
> 
> > I have a naive question here.  I was under the impression that even if a
> > record requested that monitors be posted on a field which had not changed,
> > that channel access would not actually post the monitors if the values were
> > the same.  Is this true?
> 
> Generally yes.
> 
> When a CA client opens a monitor connection, it immediately gets the current
> value in the response and it is added to a list in the record.
> 
> During record processing the record checks for its value to have changed and
> (if it has changed) sends out "value change events" to all the clients in
> the list.
> 
> Ralph Lange


One extra comment.

For numeric records (ai, ao, longin, etc) fields ADEL and MDEL are provided.
These are alarm and monitor "deadbands". Values must change by specified amounts
before monitors are issued. If these are set to a negative value then monitors
are posted everytime the record is processed.

Marty Kraimer

Replies:
Re: Monitors Brian McAllister
References:
Re: Monitors on a stringin record Ralph Lange

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