Error running example, python script for analog discovery

[Moto_NOX]

Hi,

I am trying to run the python script "Device_Enumeration.py", but cannot seem to load the dwf.dll. When I attempt to run the script in anaconda 2 or Idle (python 2.7.8), I get the following error:

runfile('C:/Users/John/.spyder2/py/Device_Enumeration.py', wdir='C:/Users/John/.spyder2/py')
Traceback (most recent call last):

  File "<ipython-input-8-4aa4827489b3>", line 1, in <module>
    runfile('C:/Users/John/.spyder2/py/Device_Enumeration.py', wdir='C:/Users/John/.spyder2/py')

  File "C:\Users\John\Anaconda2\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 685, in runfile
    execfile(filename, namespace)

  File "C:\Users\John\Anaconda2\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 71, in execfile
    exec(compile(scripttext, filename, 'exec'), glob, loc)

  File "C:/Users/John/.spyder2/py/Device_Enumeration.py", line 14, in <module>
    dwf = cdll.dwf

  File "C:\Users\John\Anaconda2\lib\ctypes\__init__.py", line 435, in __getattr__
    dll = self._dlltype(name)

  File "C:\Users\John\Anaconda2\lib\ctypes\__init__.py", line 365, in __init__
    self._handle = _dlopen(self._name, mode)

WindowsError: [Error 126] The specified module could not be found

I have copied the dwf.dll to my working directory with no luck. I am running windows 7, 64 bit.

What is the best path forward to get this working? How is the Digilent Adept Runtime used? 

Thanks,

John 

 

[attila]

Hello,

It is not needed to copy the dwf.dll to work directory.
On Windows the WaveForms Runtime installs the dwf.dll into the system path (c:/windows/system32), on 64 bit OS both 32 and 64 bit versions are installed.

Try reinstalling the WaveForms from the following page https://reference.digilentinc.com/waveforms3

Verify if your PATH Environment Variable contains %SystemRoot%\system32

[Moto_NOX]

Hi attila,

I have reinstalled WaveForms from the link provided and verified that my PATH Environment variable contains %SystemRoot%\system32. However, I still receive the same error signature show above.

I did notice I had to change permissions on the sample python scripts to enable saving them in the installed directory.

Also, I have tried this on my work computer with the same result.

Do you have another suggestion?

Thanks,

John

[attila]

Hi John,

Does it help if you replace the dwf = cdll.dwf with the following?
dwf = cdll.LoadLibrary("C:/Windows/System32/dwf.dll")

Regarding the other question, the WaveForms Runtime (dwf library) relies on Adept Runtime in communication with the device.

[Moto_NOX]

Hi Attila, 

Changing the library load to :

dwf = cdll.LoadLibrary("C:/Windows/System32/dwf.dll")

Resulted in the exact same error.

I actually tried this over the weekend with the same result. However, I tried again since I had reinstalled the SW.

Is there something basic I am missing? I do not have a lot of experience using dlls...

Thanks,

 

[attila]

Sorry, but I don't know why is the Python not loading the library for you.

Earlier I used WinPython 2.7 32bit, now I installed Anaconda 2.7 64bit and it is working with this too.

[Moto_NOX]

Hi Attila,

Thanks for trying. Can you tell me what, if any, dependencies the dwf.dll has? I am wondering if I am missing any.

Thanks,

 

[attila]

Hi,

You can try running the 32bit dwfcmd application which loads the dwf.dll:
C:\Program Files (x86)\Digilent\WaveFormsSDK\samples\dwfcmd\dwfcmd.exe connect info

You can use the http://www.dependencywalker.com/ to see which libraries are loaded or missing. In case you are using 32bit Python try the x86 version, for 64bit the x64. 
I get the following false errors.