AD2 py waveforms sdk, problem measuring analogin frequency

[abia]

my external wavegenerator is set to sine wave 2kHz with High 700mV and low 0mV. im trying to record the frequency through the ad2 osciloscope (analog in). but my output displays '0'

 

 

from ctypes import *
from dwfconstants import *
import time
import sys

if sys.platform.startswith("win"):
    dwf = cdll.dwf
elif sys.platform.startswith("darwin"):
    dwf = cdll.LoadLibrary("/Library/Frameworks/dwf.framework/dwf")
else:
    dwf = cdll.LoadLibrary("libdwf.so")

#declare ctype variables
hdwf = c_int()
voltage1 = c_double()
voltage2 = c_double()

#print(DWF version
version = create_string_buffer(16)
dwf.FDwfGetVersion(version)
print("DWF Version: "+str(version.value))

#open device
"Opening first device..."
dwf.FDwfDeviceOpen(c_int(-1), byref(hdwf))

if hdwf.value == hdwfNone.value:
    szerr = create_string_buffer(512)
    dwf.FDwfGetLastErrorMsg(szerr)
    print(szerr.value)
    print("failed to open device")
    quit()

print("Preparing to read sample...")
dwf.FDwfAnalogInChannelEnableSet(hdwf, c_int(0), c_bool(True)) 
dwf.FDwfAnalogInChannelOffsetSet(hdwf, c_int(0), c_double(0)) 
dwf.FDwfAnalogInChannelRangeSet(hdwf, c_int(0), c_double(5)) 
dwf.FDwfAnalogInConfigure(hdwf, c_bool(False), c_bool(False)) 

time.sleep(2)
z = 0

for i in range(4):
    time.sleep(1.66)
    dwf.FDwfAnalogInStatus(hdwf, False, None) 
    dwf.FDwfAnalogInStatusSample(hdwf, c_int(0), byref(voltage1))
    dwf.FDwfAnalogInStatusSample(hdwf, c_int(1), byref(voltage2))
    print("Channel 1:  " + str(voltage1.value)+" V")
    print("Channel 2:  " + str(voltage2.value)+" V")
    dwf.FDwfAnalogInFrequencyGet(hdwf, z)
    print("Freq: " + str(z) )

    print('---------------------------')
dwf.FDwfDeviceCloseAll()

 

 

#####

DWF Version: b'3.18.1'
Preparing to read sample...
Channel 1:  0.25451508173897247 V
Channel 2:  -0.0023014079845233293 V
Freq: 0
---------------------------
Channel 1:  0.44609468785736645 V
Channel 2:  0.012614214611239793 V
Freq: 0
---------------------------
Channel 1:  0.6771269877313809 V
Channel 2:  0.012614214611239793 V
Freq: 0
---------------------------
Channel 1:  0.05825464754787773 V
Channel 2:  0.027529837207002916 V
Freq: 0
---------------------------

Process finished with exit code 0

[attila]

Hi @abia

With the above script you are just reading one ADC conversion at a time.
To identify the peak frequency component see the WF SDK/ samples/ py/ AnalogIn_Spectrum.py AnalogIn_FFT.py examples
https://forum.digilent.com/topic/8908-waveforms-beta-download/

 

[abia]

Hey Attila! Thanks for getting back so fast.

So Im trying out those two samples but I dont see where either of those utilize a get frequency function. Is there an analoginfrequencyget() function of sorts? and if not any recommendations on how to get the real time frequency of an input signal to the oscilloscope?

Thanks so much

 

 

 

Edited July 29, 2022 by abia

[attila]

Hi @abia

On 7/29/2022 at 7:55 PM, attila said:

To identify the peak frequency component see the WF SDK/ samples/ py/ AnalogIn_Spectrum.py AnalogIn_FFT.py examples
https://forum.digilent.com/topic/8908-waveforms-beta-download/