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

Subject: Re: Use case for ao record HOPR != DRVH or LOPR != DRVL?
From: Andrew Johnson <anj@aps.anl.gov>
To: <tech-talk@aps.anl.gov>
Date: Tue, 30 May 2017 12:32:31 -0500
On 05/30/2017 11:52 AM, Pete Jemian wrote:
> That use case is not so convincing.  Plot zoom seems a GUI client
> feature rather than a feature common to all clients of an ao PV.

Right, but the default is for the GUI client to start by displaying the
range LOPR..HOPR.

For another example you might want to display multiple signals that have
slightly different DRV* ranges all on the same graph, using the same Y
axis for all of them.

It seems obvious to me that while the two ranges are often going to be
the same (for the simple case at least), they shouldn't *have* to be,
hence they need different fields to control them.

- Andrew


> On 5/30/2017 11:50 AM, Mark Rivers wrote:
>> One use case would be when you want to zoom into a plot of the PV
>> without restricting the actual output values.  You can set HOPR and
>> LOPR without changing DRVH and DRVL.
>>
>> -----Original Message-----
>> From: tech-talk-bounces@aps.anl.gov
>> [mailto:tech-talk-bounces@aps.anl.gov] On Behalf Of J. Lewis Muir
>> Sent: Tuesday, May 30, 2017 11:42 AM
>> To: EPICS Tech-Talk
>> Subject: Use case for ao record HOPR != DRVH or LOPR != DRVL?
>>
>> Hello, Tech-Talkers!
>>
>> I understand that for the ao (Analog Output) record, the HOPR and LOPR
>> fields are used for the display limits and the DRVH and DRVL fields are
>> used for the control limits.  However, I always end up setting HOPR =
>> DRVH and LOPR = DRVL.  What's a use case where the display limits would
>> be different from the control limits (i.e., HOPR != DRVH or LOPR !=
>> DRVL)?
>>
>> Thanks!
>>
>> Lewis
>>
> 

-- 
Arguing for surveillance because you have nothing to hide is no
different than making the claim, "I don't care about freedom of
speech because I have nothing to say." -- Edward Snowdon

References:
Use case for ao record HOPR != DRVH or LOPR != DRVL? J. Lewis Muir
RE: Use case for ao record HOPR != DRVH or LOPR != DRVL? Mark Rivers
Re: Use case for ao record HOPR != DRVH or LOPR != DRVL? Pete Jemian

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