Re: Real-Time Spectral Analysis of streaming data in EPICS operator screens.

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

Hi Richard,

The areaDetector framework contains a plugin and GUI screens for computing and displaying FFTs.  It can be used for 1-D or 2-D arrays and FFTs.

Documentation:

https://areadetector.github.io/areaDetector/ADCore/NDPluginFFT.html

Source code:

https://github.com/areaDetector/ADCore/blob/master/ADApp/pluginSrc/NDPluginFFT.cpp

To use it you would need to modify the driver to inherit from asynNDArrayDriver:

https://areadetector.github.io/areaDetector/ADCore/NDArray.html#asynndarraydriver

https://github.com/areaDetector/ADCore/blob/master/ADApp/ADSrc/asynNDArrayDriver.cpp

The driver will package the ADC data into an NDArray object and then call registered plugins with that array.  Those plugins can include NDPluginFFT. 

An advantage of this approach is that you also get other plugins that may be useful, including statistics and file writers.  You can stream your ADC data to an HDF5 file with metadata like the ADC gains, etc.

Mark

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Evans, Richard K. (GRC-H000) via Tech-talk <tech-talk at aps.anl.gov>
Sent: Friday, June 23, 2023 4:23 PM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Cc: Evans, Richard K. (GRC-H000) <richard.k.evans at nasa.gov>
Subject: Real-Time Spectral Analysis of streaming data in EPICS operator screens.

 

Hello,

What software tools/components would best enable an EPICS system to render real-time frequency plots (fft/psd) of single channels of data as it is being recorded? Is that possible within CSS/Phoebus? I can't find any mention in the CSS documentation about displaying live frequency plots). 

Elaine Chandler's User meeting talk on April 25th, 2023 at Fermilab, titled: "C2 Data Viewer: Visualization tool for EPICS7 Data Streaming" [1] describes a DAQ "scope" application that I would like to consider using, but I was told that this capability also exists in other tools as well and I should learn about all the tools that do this before deciding how to implement this. Is this (real-time spectral display of data) a common capability? What does the community recommend? Thanks!

(Assume the underlying EPICS system is acquiring data using an FMC IOC with fast ADCs -  i.e. Marble [2] and Zest [3] at 50 kSPS)

Thanks!
/Rich

[1] https://indico.fnal.gov/event/58280/contributions/264784/
[2] https://github.com/BerkeleyLab/Marble
[3] https://github.com/BerkeleyLab/Zest

- Richard Evans, NASA GRC - Armstrong Test Facility
  Data and Information Systems Management
  Public URI: https://www.linkedin.com/in/rkevans 
  Agency URI: https://wiki.grc.nasa.gov/pbgeneral/User:Rkevans