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PyVISA not listing USB instrument on Linux

I am trying to communicate with a LeCroy WaveRunner 640Zi oscilloscope from a Raspberry Pi, they are connected with a USB cable. I have already done this under Windows, but now I am not able to make it work in Linux.
If I run lsusb I see this:
$ lsusb
Bus 001 Device 009: ID 05ff:1023 LeCroy Corp.
...
If I now go to Python I get this:
$ python3
Python 3.7.3 (default, Dec 20 2019, 18:57:59)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pyvisa
>>> pyvisa.ResourceManager().list_resources()
('ASRL/dev/ttyAMA0::INSTR',)
>>>
The oscilloscope is not there (the ASRL/dev/ttyAMA0::INSTR I think is something from the Raspberry Py itself). The oscilloscope is properly configured, I think, because if I go to the options (using the screen from the scope itself) and go to "remote options" I see that it is set up for USB and the VISA address is USB0::bla::bla::bla::INSTR.
I tried to proceed as explained in this page but did not work. If I run python3 -m visa info I get
$ python3 -m visa info
~/.local/lib/python3.7/site-packages/visa.py:23: FutureWarning: The visa module provided by PyVISA is being deprecated. You can replace `import visa` by `import pyvisa as visa` to achieve the same effect.
The reason for the deprecation is the possible conflict with the visa package provided by the https://github.com/visa-sdk/visa-python which can result in hard to debug situations.
FutureWarning,
Machine Details:
Platform ID: Linux-4.19.97-v7+-armv7l-with-debian-10.3
Processor:
Python:
Implementation: CPython
Executable: /usr/bin/python3
Version: 3.7.3
Compiler: GCC 8.3.0
Bits: 32bit
Build: Dec 20 2019 18:57:59 (#default)
Unicode: UCS4
PyVISA Version: 1.11.3
Backends:
ivi:
Version: 1.11.3 (bundled with PyVISA)
Binary library: Not found
py:
Version: 0.5.2
ASRL INSTR: Available via PySerial (3.4)
USB INSTR: Available via PyUSB (1.0.2). Backend: libusb1
USB RAW: Available via PyUSB (1.0.2). Backend: libusb1
TCPIP INSTR: Available
TCPIP SOCKET: Available
GPIB INSTR:
Please install linux-gpib (Linux) or gpib-ctypes (Windows, Linux) to use this resource type. Note that installing gpib-ctypes will give you access to a broader range of funcionality.
No module named 'gpib'
I have also tried to connect with the oscilloscope without "listing the resources" by doing pyvisa.ResourceManager().open_resource('USB0::bla::bla::bla::INSTR') but I get:
>>> osc = pyvisa.ResourceManager().open_resource('USB0::0x05ff::0x1023::2810N60091::INSTR')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "~/.local/lib/python3.7/site-packages/pyvisa/highlevel.py", line 3304, in open_resource
res.open(access_mode, open_timeout)
File "~/.local/lib/python3.7/site-packages/pyvisa/resources/resource.py", line 298, in open
self._resource_name, access_mode, open_timeout
File "~/.local/lib/python3.7/site-packages/pyvisa/highlevel.py", line 3232, in open_bare_resource
return self.visalib.open(self.session, resource_name, access_mode, open_timeout)
File "~/.local/lib/python3.7/site-packages/pyvisa_py/highlevel.py", line 167, in open
sess = cls(session, resource_name, parsed, open_timeout)
File "~/.local/lib/python3.7/site-packages/pyvisa_py/sessions.py", line 323, in __init__
self.after_parsing()
File "~/.local/lib/python3.7/site-packages/pyvisa_py/usb.py", line 84, in after_parsing
self.parsed.serial_number,
File "~/.local/lib/python3.7/site-packages/pyvisa_py/protocols/usbtmc.py", line 287, in __init__
super(USBTMC, self).__init__(vendor, product, serial_number, **kwargs)
File "~/.local/lib/python3.7/site-packages/pyvisa_py/protocols/usbtmc.py", line 199, in __init__
raise ValueError("No device found.")
ValueError: No device found.
>>>

I managed to find a solution which I share for the sake of future generations to come. I had just to add a line to the file /etc/udev/rules.d/99-com.rules with the content SUBSYSTEM=="usb", MODE="0666", GROUP="usbusers" (or append this line in case the file already exists) and then restart the computer. In summary:
Enter into the sudo environment:
sudo su
Now add the required line into the respective file:
echo 'SUBSYSTEM=="usb", MODE="0666", GROUP="usbusers"' >> /etc/udev/rules.d/99-com.rules
Restart the computer.
Enjoy.
$ python3
Python 3.7.3 (default, Dec 20 2019, 18:57:59)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pyvisa
>>> pyvisa.ResourceManager().list_resources()
('ASRL/dev/ttyAMA0::INSTR', 'USB0::bla::bla::bla::INSTR')
>>> osc = pyvisa.ResourceManager().open_resource('USB0::bla::bla::bla::INSTR')
>>> osc.query('*IDN?')
'*IDN LECROY,WR640ZI,LCRY28blablabla,7.7.1\n'

iPython: DLL load failed: The specified module could not be found; plain Python fine

I keep getting this (well known) error in iPython. Yet, the same import works fine in plain Python. (Python 3.3.5, see details below)
iPython:
Python 3.3.5 (v3.3.5:62cf4e77f785, Mar 9 2014, 10:37:12) [MSC v.1600 32 bit (Intel)]
Type "copyright", "credits" or "license" for more information.
IPython 2.0.0 -- An enhanced Interactive Python.
? -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help -> Python's own help system.
object? -> Details about 'object', use 'object??' for extra details.
In [1]: import test1
---------------------------------------------------------------------------
ImportError Traceback (most recent call last)
<ipython-input-7-ddb30f03c287> in <module>()
----> 1 import test1
ImportError: DLL load failed: The specified module could not be found.
Python (not only it loads fine, it also works):
$ python
Python 3.3.5 (v3.3.5:62cf4e77f785, Mar 9 2014, 10:37:12) [MSC v.1600 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import test1
>>>
Now, Dependency Walker on test1.pyd shows this
[ ? ] LIBGCC_S_DW2-1.DLL Error opening file. The system cannot find the file specified (2).
[ ? ] LIBSTDC++-6.DLL Error opening file. The system cannot find the file specified (2).
[ ? ] PYTHON33.DLL Error opening file. The system cannot find the file spec
I even overwrote sys.path in iPython with the one from plain Python. The file test1.pyd is in C:\Test.
['c:\\Test',
'c:\\WinPython-32bit-3.3.5.0\\python-3.3.5\\python33.zip',
'c:\\WinPython-32bit-3.3.5.0\\python-3.3.5\\DLLs',
'c:\\WinPython-32bit-3.3.5.0\\python-3.3.5\\lib',
'c:\\WinPython-32bit-3.3.5.0\\python-3.3.5',
'c:\\WinPython-32bit-3.3.5.0\\python-3.3.5\\lib\\site-packages',
'c:\\WinPython-32bit-3.3.5.0\\python-3.3.5\\lib\\site-packages\\FontTools',
'c:\\WinPython-32bit-3.3.5.0\\python-3.3.5\\lib\\site-packages\\win32',
'c:\\WinPython-32bit-3.3.5.0\\python-3.3.5\\lib\\site-packages\\win32\\lib',
'c:\\WinPython-32bit-3.3.5.0\\python-3.3.5\\lib\\site-packages\\Pythonwin']
Why would the import work in plain Python but not in iPython?

I have encountered the same problem. After hours looking and thinking I found out the cause. The difference is environment variables between interpreters (plain python and ipython or pycharm etc.). I think your can use %env in ipython to check the environment variables. In plain python, use (works in python 3.7):
import os
os.environ
Then if there are differences, maybe you should set the right one before your run.
Actually there are multiple ways to set envs. For example
os.environ['key']='value' #Both key and value are strings
or
os.putenv('key', 'value')
Here key is the name of the environment variable, and value is the value you want to set it to.
Hope this helps you.~~~///(^v^)\\~~~

Pycharm 4 no module named ROOT, when importing a locally installed module (PyROOT), that is working fine from shell on Mac OS X Yosemite

I am trying to set up PyROOT to work with Pycharm 4 on Mac OS X Yosemite.
I have installed ROOT (locally), with the python option enabled, and set up all of the necessary environment paths.
echo $PYTHONPATH
/Users/natalia/Software/root/lib:/Users/natalia/Software/root/bin:/Users/natalia/Software/root
It works just fine from the shell interpreter:
python
Python 2.7.6 (default, Sep 9 2014, 15:04:36)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.39)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import ROOT
>>> ROOT.__file__
'/Users/natalia/Software/root/lib/ROOT.pyc'
>>>
In Pycharm I have tried to add these paths to the interpreter using Preferences->Project Interpreter->More->Show paths...
The paths that show there are the following:
file:///Library/Python/2.7/site-packages/pip-6.1.1-py2.7.egg
file:///Users/natalia/Software/root/lib
file:///System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7
file:///System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin
file:///System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac
file:///System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages
file:///System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python
file:///System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk
file:///System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload
file:///System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/PyObjC
file:///Library/Python/2.7/site-packages
file:///Users/natalia/Software/root/bin
file:///Users/natalia/Software/root
I created the following file in Pycharm:
import os
os.system("echo $PYTHONPATH")
import ROOT
When run, it returns this:
Traceback (most recent call last):
/Users/natalia/Software:/Users/natalia/Software/root:/Users/natalia/Work/Projects/untitled
File "/Users/natalia/Work/Projects/untitled/l.py", line 3, in <module>
import ROOT
ImportError: No module named ROOT
Notice how this PYTHONPATH that's printed from python in Pycharm doesn't include (for a reason unknown to me) the path that actually includes the ROOT.pyc file, that is: '/Users/natalia/Software/root/lib'
I have also tried doing the dirty trick of
os.system("export PYTHONPATH=$PYTHONPATH:/Users/natalia/Software/root/lib")
but I found it doesn't actually change the path if I print it afterwards.
I am absolutely confused as to where Pycharm gets the paths from.
Any possible solutions would be welcome and greatly appreciated.

You may have figured this out already, but just in case...
import sys
sys.path.append('/Applications/Misc/root/lib')
import ROOT
print ROOT.TTimeStamp().AsString()
will add that search path to Python (& PyCharm by extension); the snippet gives me the following output in PyCharm:
/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7
/Users/rrios/PycharmProjects/untitled/dummy.py
Thu, 02 Jul 2015 01:07:57 UTC +628998000 nsec
Process finished with exit code 0

Connecting to Informix with pyodbc on Windows

I am attempting to write a process in python that needs to be portable between different database environments. One of the environments that it must be able to connect to is Informix.
I've been searching for how to connect to Informix in Python and have come across both InformixDB and ibm_db{,_sa}, both of which seem overly difficult to use (and I've tried and tried and just can't get them working).
I'm trying (again) to get this working with pyodbc but can't establish a connection to the database from Windows:
set INFORMIXDIR="C:\Program Files\IBM Informix Client SDK"
set CLIENT_LOCALE=en_US.CP1252
set DB_LOCALE=en_US.819
python
Python 3.3.3 (v3.3.3:c3896275c0f6, Nov 18 2013, 21:18:40) [MSC v.1600 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> import pyodbc
>>>
>>> cnxn = pyodbc.connect(dsn='devdb')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
pyodbc.Error: ('HY000', '[HY000] [Informix][Informix ODBC Driver][Informix]Unspecified System Error = -23101. (-23101) (SQLDriverConnect)')
From what I've found, Error -23101 is caused by the Locale's not matching correctly, however these are the same values used in the ODBC configuration as well as any other Informix-related utility that I have at my disposal.
I am at a loss to figure out how to connect to Informix and can't think of any more search terms to use to try and figure out this issue. How can it be so difficult to use ODBC - almost every other language I know doesn't have a problem with it!
Note: just to be clear, the ODBC connection is configured correctly and works with other ODBC-based applications (I can connect using QTODBC or Perl DBI).
Thanks in advance for any help.
Edit: Heh, I'm not reputable enough to attach an image yet, but I've uploaded it at http://wraeth.id.au/wp-content/uploads/2014/10/odbcad32.png if you want to have a look.
Edit 2:
Updated to ActivePython-3.3.4 with no change
Created symbolic link to IFX ClientSDK dir to remove spaces in path resulting in "The driver did not supply an error"
Confirmed DB_LOCALE is en_US.819 by checking the sysdbslocale table in the database.
Also, confirmed that %INFORMIXDIR% is set to a valid CSDK installation:
> mklink /D informix "C:\Program Files\IBM Informix Client SDK"
> set INFORMIXDIR=C:\informix
> dir %INFORMIXDIR%\gls
Volume in drive C has no label
Volume Serial Number is 808D-98FF
Directory of C:\informix\gls
19/09/2013 04:50 PM <DIR> .
19/09/2013 04:50 PM <DIR> ..
19/09/2013 04:50 PM <DIR> cm3
19/09/2013 04:50 PM <DIR> cv9
19/09/2013 04:50 PM <DIR> dll
19/09/2013 04:50 PM <DIR> etc
19/09/2013 04:50 PM <DIR> lc11
Using the symbolic link as INFORMIXDIR still doesn't allow it to connect:
ActivePython 3.3.4.1 (ActiveState Software Inc.) based on
Python 3.3.4 (default, Feb 25 2014, 15:11:05) [MSC v.1600 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import os, pyodbc
>>> os.path.exists(
... os.path.join(
... os.environ.get('INFORMIXDIR'),
... 'gls'
... )
... )
True
>>> cnxn = pyodbc.connect(dsn='devdb', uid='user', pwd='password')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
pyodbc.Error: ('HY000', 'The driver did not supply an error!')
Solution
Uninstalling and reinstalling the Client SDK to a path that didn't have spaces (C:\informix) seems to have resolved the issue.

It should be comment, but is too long.
While I cannot reproduce your error I have some ideas.
Reinstall ClientSDK and install it in c:\informix directory setting it as %INFORMIXDIR%. This should change ODBC registry entries about driver:
[HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBCINST.INI\IBM INFORMIX ODBC DRIVER]
"Driver"="C:\\informix\\bin\\iclit09b.dll"
"Setup"="C:\\informix\\bin\\iclit09b.dll"
and about database (devdb is my DSN)
[HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\ODBC.INI\devdb]
"Driver"="C:\\informix\\bin\\iclit09b.dll"
(those entries are from 32 bit Windows)
I advice it after reading answers and comments to: Informix connection works through Windows, but not through Cygwin
If you have ActiveState Python then you can use odbc module instead of pyodbc. Is is part of win32 package and works only on Windows but maybe it can connect with your database. You can open database with:
import odbc
cnxn = odbc.odbc('devdb/user/password')
If some ODBC software works then you can enable tracing ODBC and compare traces. It would be useful especially if you can connect from odbc module but not from pyodbc.

python import cx_Oracle error on cygwin

I tried to install cx_Oracle from pypi source since there is no available port for it in cygwin. I did make some changes as suggested in http://permalink.gmane.org/gmane.comp.python.db.cx-oracle/2492 and modified my setup.py. However, I still get the following error :-
$ python
Python 2.7.3 (default, Dec 18 2012, 13:50:09)
[GCC 4.5.3] on cygwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import cx_Oracle
/usr/lib/python2.7/site-packages/cx_Oracle-5.1.3-py2.7-cygwin-1.7.24-i686.egg/cx_Oracle.py:3: UserWa
rning: Module cx_Oracle was already imported from /usr/lib/python2.7/site-packages/cx_Oracle-5.1.3-p
y2.7-cygwin-1.7.24-i686.egg/cx_Oracle.pyc, but /home/zerog/cx_Oracle-5.1.3 is being added to sys.pat
h
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "build/bdist.cygwin-1.7.24-i686/egg/cx_Oracle.py", line 7, in <module>
File "build/bdist.cygwin-1.7.24-i686/egg/cx_Oracle.py", line 6, in __bootstrap__
ImportError: Exec format error
>>>
If someone can please help me fix this ?
TIA.

Fixed this by specifying the path to instantclient as below :
$ export PATH=$PATH:/cygdrive/d/Tools/instantclient_11_2
(Other, possibly important stuff) :
$ echo $LD_LIBRARY_PATH
/cygdrive/d/Tools/instantclient_11_2
$ echo $ORACLE_HOME
/cygdrive/d/Tools/instantclient_11_2
Now, I get :-
$ python
Python 2.7.3 (default, Dec 18 2012, 13:50:09)
[GCC 4.5.3] on cygwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import cx_Oracle
>>>

It's hard to pin down from the error message alone, but I am guessing that you have two different copies of cx_Oracle in your sys.path. The error message is complaining that a different version of the same module had already been import-ed.
Presumably the pristine upstream version is installed system-wide in /usr/lib/python2.7/site-packages/cx_Oracle-5.1.3-py2.7-cygwin-1.7.24-i686.egg, and your modified version in /home/zerog/cx_Oracle-5.1.3.
Does it work if you pare down sys.path so that only the original, or only your modified version, is included?
(You might want to use virtualenv if you need to switch back and forth between two versions frequently.)

I ran into this error "Exec format error."
For me, this was likely caused by a mismatch between cygwin being installed as 64 bit, but the instant client being installed as 32 bit. Double check that everything (oracle, cygwin) is either 32 bit or 64 bit.
What fixed my issue:
Since my cygwin is 64 bit (see uname -a, and look for x86_64), I downloaded the 64 bit instant client from oracle's website, and unzipped
I set the env vars in .profile, to point where it was unzipped:
export ORACLE_HOME=/cygdrive/c/oracle/instantclient_x64_11_2
export LD_LIBRARY_PATH=$ORACLE_HOME
export DYLD_LIBRARY_PATH=$ORACLE_HOME
export TNS_ADMIN='//optional/path/to/your/oracle/tns/files/'
source ~/.profile
To test, you should now be able to run this python command with no error:
import cx_Oracle
To verify the path is correct, if you run ls, you should see something like
ls $ORACLE_HOME
adrci.exe genezi.exe oci.sym ociw32.dll ojdbc6.jar
oraocci11.dll oraociei11.sym uidrvci.exe vc9
adrci.sym genezi.sym ocijdbc11.dll ociw32.sym orannzsbb11.dll
oraocci11.sym orasql11.dll uidrvci.sym xstreams.jar
BASIC_README oci.dll ocijdbc11.sym ojdbc5.jar orannzsbb11.sym
oraociei11.dll orasql11.sym vc8