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

Subject: Re: saving samples
From: Ralph Lange <ralph.lange@gmx.de>
To: EPICS Tech Talk <tech-talk@aps.anl.gov>
Date: Tue, 13 Jun 2017 19:50:17 +0200
One of the functionalities of the compress record is acting as a ring buffer (for scalar values).

For arrays it can do averages. Either average over time, i.e. multiple array samples - like a scope - or average over multiple elements. If you combine two compress records after e.g. a temperature that gets updated every second, you can - in the first step - have a 3600 element time buffer over the last hour, then - in the second step - do a 60:1 average and have a 60 element buffer of the temperature averages of the last 60 minutes.

Cheers,
~Ralph


On Tue, Jun 13, 2017 at 6:06 PM, Miguel Bordalo <miguel.b.fernandes@gmail.com> wrote:
save in another PV the last sample (scalar) (or more samples) of other PV that is updated periodically.
this is for example: i have the temperature of a room being updated periodically. I want another PV to act as a buffer that stores the last two samples of the room's temperature . And i want to be able to acess them individually of course.
Thanks! 

-------------------------------------------------------------------------
Miguel Bordalo

Licenciado em Engenharia Electrotécnica e de Computadores
Instituto Superior Técnico

miguel.b.fernandes@gmail.com


On 13 June 2017 at 16:01, Ralph Lange <ralph.lange@gmx.de> wrote:
Please clarify a bit further.

What do you mean by "save"?
Write to a file? Store in an archiver? Write to another record?
What kind of PV?
Scalar or array data?
If array: does "last" mean last array in time, or last element in array?

Cheers,
~Ralph


On Tue, Jun 13, 2017 at 4:18 PM, Miguel <miguel.b.fernandes@gmail.com> wrote:
What is the easiest way to save periodicaly the last sample (or last 2/3 samples) of a certain PV ?

ty




References:
saving samples Miguel
Re: saving samples Ralph Lange
Re: saving samples Miguel Bordalo

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