import errors for thorlabs apt motion controller

[aidenleefb]

Hello, I am trying to interface Thorlabs apt motion controller using a python script.

I am looking at the instruction on your github page GitHub - qpit/thorlabs_apt: python module for Thorlabs' APT library

In step #3 of the installation instruction, you mention that I should copy APT.dll from APT installation path\APT Server directory to Windows\System32 location.

I tried this option but when I try:

Import thorlabs_apt as apt

My program will crash without giving me any errors.

If I remove the APT.dll from Windows\System32 location, it generates the following errors:

File "C:\Users\aidenlee1\AppData\Roaming\Python\Python37\site-packages\shiboken2\files.dir\shibokensupport_feature_.py", line 142, in import
return original_import(name, *args, *kwargs)
File "C:\Users\aidenlee1*hidden", line 5, in
import thorlabs_apt as apt
File "C:\Users\aidenlee1\AppData\Roaming\Python\Python37\site-packages\shiboken2\files.dir\shibokensupport_feature.py", line 142, in import
return original_import(name, *args, *kwargs)
File "C:\Users\aidenlee1\Anaconda3\envs*hidden\lib\site-packages\thorlabs_apt_init.py", line 1, in
from .core import *
File "C:\Users\aidenlee1\AppData\Roaming\Python\Python37\site-packages\shiboken2\files.dir\shibokensupport_feature_.py", line 142, in import
return original_import(name, args, kwargs)
File "C:\Users\aidenlee1\Anaconda3\envs*hidden\lib\site-packages\thorlabs_apt\core.py", line 1376, in
_lib = _load_library()
File "C:\Users\aidenlee1\Anaconda3\envs*hidden\lib\site-packages\thorlabs_apt\core.py", line 1360, in _load_library
lib = ctypes.windll.LoadLibrary(filename)
File "C:\Users\aidenlee1\Anaconda3\envs*hidden\lib\ctypes_init.py", line 442, in LoadLibrary
return self.dlltype(name)
File "C:\Users\aidenlee1\Anaconda3\envs*hidden*\lib\ctypes_init.py", line 364, in init
self._handle = _dlopen(self._name, mode)
OSError: [WinError 126] The specified module could not be found

Based on my testing, the error is generated from import thorlabs_apt as apt.

Some other setting I am using are:

1. anaconda virtual environment
2. Python version 3.7.8

Some other observations:

1. If I add APT.dll from APT installation path\APT Server directory to Windows\System32 location and create a single threaded application, I can control the motor
2. if I create a second thread or use it with pyqt, the program crashes without error

If possible, could you help me solve this issue?

Kind regards,

-Aiden

I am getting this same effect about 5 out of 10 attempts to import. I have no information to add.

[gavinfunr]

I am also using a venv and getting this error

I was eventually forced to use a child process created from my main script, which takes a position argument and attempts to import the DLL and move the motor to that position. I use it in a retry loop in case it crashes which sometimes happen.