Experimental Physics and
Industrial Control System

Try Python.  This example needs PyEpics and h5py packages.

Here is an example:

* demo.db  example database
* demo.py  example python program
* demo.h5  example HDF5 output

Run attached demo.db with a softIoc (from EPICS base):

     softIoc -d demo.db

In separate terminal, run the demo program:

     python3 demo.py

See the output in demo.h5.  The content looks like this:

/tmp/demo/demo.h5
   wf10:float64[3] = [2.0, 4.0, 8.0]
   wf5:float64[5] = [1.0, 2.0, 3.0, 4.0, 5.0]

Pete

On 8/8/2020 3:41 PM, Ha, Kiman via Tech-talk wrote:
> Hi All,
> 
> NSLS-II LLRF system has a new circular buffer for the LLRF system 
> oscilloscope function.
> 
> A single waveform size is 1.8 M point and a total of ~40 PVs.
> 
> Does anyone have and any EPICS HDF client program for waveform PVs to 
> HDF5 files?
> 
> Our application is simple steps if the beam dump caused? Read waveforms 
> and write HDF5 files to a specific directory (DD/MM/YYYY).
> 
> 
> Thanks,
> 
> Kiman
> 

-- 
----------------------------------------------------------
Pete R. Jemian, Ph.D.                 <jemian at anl.gov>
Beam line Controls and Data Acquisition (BC, aka BCDA)
Advanced Photon Source,    Argonne National Laboratory
Argonne, IL  60439                    630 - 252 - 3189
-----------------------------------------------------------
       Education is the one thing for which people
          are willing to pay yet not receive.
-----------------------------------------------------------

# demo.db: read waveforms from EPICS and write HDF5 file

# softIoc -d demo.db

record(waveform, "demo:wf10") {
    field(NELM, 10)
    field(FTVL, "DOUBLE")
    field(EGU, "arbitrary")
}

record(waveform, "demo:wf5") {
    field(NELM, 5)
    field(FTVL, "DOUBLE")
    field(EGU, "arbitrary")
}

Attachment: demo.h5
Description: demo.h5

#!/usr/bin/env python

"""demo: read waveforms from EPICS and write HDF5 file"""

import epics
import h5py

wf5 = epics.PV("demo:wf5")
wf10 = epics.PV("demo:wf10")
for obj in (wf5, wf10):
    obj.wait_for_connection()

wf5.put([1,2,3,4,5])
wf10.put([2, 4, 8])

with h5py.File("demo.h5", "w") as fp:
    fp.create_dataset("wf5", data=wf5.value)
    ds = fp.create_dataset("wf10", data=wf10.value)
    ds.attrs["units"] = "arbitrary"

References:

HDF5 client for EPICS 3.15 Ha, Kiman via Tech-talk

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