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<== Date ==> <== Thread ==>
Subject: RE: Increasing scan rate to 10 kHz
From: Emmanuel Mayssat <[email protected]>
To: Evgeniy <[email protected]>, EPICS mailing list <[email protected]>
Date: Tue, 26 Nov 2013 17:00:09 -0800
You need hardware with proper clock and in particular a hardware circular buffer which you populate with your samples.
Software wise, you read the hardware buffer at a much lower frequency, but fast enough so it doesn't wrap around.
(i.e. set the size of the hardware buffer correctly and use 2 pointers (last data written, last data read))
Read all the new data from the hardware buffer **at once** and append it to your compress record.

What are you sampling and how do you currently intend to do it?
can you lose chunks of data?

Good luck!
--
Emmanuel


> Date: Tue, 26 Nov 2013 15:20:22 -0800
> From: [email protected]
> To: [email protected]
> Subject: Increasing scan rate to 10 kHz
>
> Hello,
>
> I can easily set scan period to 0.01 second by adding:
>
> choice(menuScan_01_second,".01 second")
>
> in dbd file.
>
> What about adding scan period 0.0001 second?
> Similar line:
>
> choice(menuScan_0001_second,".0001 second")
>
> doesn't work.
>
> CLOCKS_PER_SECOND on my 8-core DELL server is 1000000 (running SL5.4).
>
> What should I do to set scan period to 0.0001 second?
>
> I need such short period to quickly fill in the circular buffer of
> compress record.
>
> Thanks,
> Evgeniy
>
References:
Increasing scan rate to 10 kHz Evgeniy
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