AD2, record continously using whole buffer

[Weevil]

I am a bit confused, in the following example i am using continiously the record mode and programmed a time.sleep(0.1) in my aquisition loop. So i would expect the new aquired samples should be the whole buffer size (nsamples = 15000) because there should be 50000000 new samples/s. But actual it is variating between ~150 -~ 8000 per loop. What i am doing wrong?

 

#set samplerate
libdwf.FDwfAnalogInFrequencySet(hdwf, c_double(50000000))

#set up acquisition
libdwf.FDwfAnalogInChannelEnableSet(hdwf, c_int(0), c_bool(True))
libdwf.FDwfAnalogInChannelRangeSet(hdwf, c_int(0), c_double(5))

libdwf.FDwfAnalogInAcquisitionModeSet(hdwf, c_int(3)) #record

libdwf.FDwfAnalogInRecordLengthSet(hdwf, c_double(0))

            
#wait at least 2 seconds for the offset to stabilize
time.sleep(2)

#begin acquisition
libdwf.FDwfAnalogInConfigure(hdwf, c_int(0), c_int(1))       
          
cSamples = 0
nSamples = 15000

for i in range(100):

    
    rgdSamples1 = (c_double*nSamples)()
    rgdSamples2 = (c_double*nSamples)()
    

    libdwf.FDwfAnalogInStatus(hdwf, c_int(1), byref(sts))
    if cSamples == 0 and (sts == DwfStateConfig or sts == DwfStatePrefill or sts == DwfStateArmed) :
        # Acquisition not yet started.
        continue

    libdwf.FDwfAnalogInStatusRecord(hdwf, byref(cAvailable), byref(cLost), byref(cCorrupted))

    cSamples += cLost.value
        
    if cLost.value :
        fLost = 1
    if cCorrupted.value :
        fCorrupted = 1

    if cAvailable.value==0 :
        continue

    if cSamples+cAvailable.value > nSamples :
        cAvailable = c_int(nSamples-cSamples)
    
    # get samples1
    libdwf.FDwfAnalogInStatusData(hdwf, c_int(0), byref(rgdSamples1, 8*cSamples), cAvailable)
    
    
    results = np.array(rgdSamples1)
    
    XX = results[np.nonzero(results)]
    
    print(len(XX))
    
    time.sleep(0.1)

 

[attila]

Hello,

The record mode can stream through USB at up to 1-2Msps. For such high rates reduce, or better remove the sleep.
For higher sample rates use device buffered acquisitions, up to 100Msps and 8/16k samples.