Win7 AttributeError: 'Device' object has no attribute 'serial_number'

[marcDesm]

I'm trying to access a USBTMC device (B&K Precision power supply) with a non NI backend with pyvisa on a Win 7 PC. It works with NI as the back end. But not with pyvisa-py.

A problem happen with the serial library (which I don't need pyvisa-py to use) when I call "visa.ResourceManager('@py')".

I get an exception that ends with AttributeError: 'Device' object has no attribute 'serial_number'

Here are some details:

C:\Users\ss745c\Documents\IT\Python\pyvisa\pyvisa-py-master>python -m visa info Machine Details: Platform ID: Windows-7-6.1.7601-SP1 Processor: Intel64 Family 6 Model 79 Stepping 1, GenuineIntel

Python: Implementation: CPython Executable: C:\Python27\python.exe Version: 2.7.13 Compiler: MSC v.1500 64 bit (AMD64) Bits: 64bit Build: Dec 17 2016 20:53:40 (#v2.7.13:a06454b1afa1) Unicode: UCS2

PyVISA Version: 1.8

Backends: ni: Version: 1.8 (bundled with PyVISA)

1: C:\Windows\system32\visa32.dll:

     found by: auto
     bitness: 64
    Vendor: National Instruments
     Impl. Version: 17825792
     Spec. Version: 5244672
  #2: C:\Windows\system32\visa32.dll:
     found by: auto
     bitness: 64
     Vendor: National Instruments
     Impl. Version: 17825792
     Spec. Version: 5244672

py: Version: 0.3.dev0 ASRL INSTR: Available via PySerial (3.2.1) TCPIP INSTR: Available USB RAW: Available via PyUSB (N/A). Backend: libusb10 USB INSTR: Available via PyUSB (N/A). Backend: libusb10 GPIB INSTR: Please install linux-gpib to use this resource type. No module named gpib TCPIP SOCKET: Available

Result of trying to use visa.ResourceManager('@py')

File "C:\Users\ss745c\Documents\El Segundo\PROJECTS\FMS\Python\fmsControllerV51c\power.py", line 311, in connect self.parent.getListOfVisaInstruments() File "C:\Users\ss745c\Documents\El Segundo\PROJECTS\FMS\Python\fmsControllerV51c\power.py", line 55, in getListOfVisaInstruments self.resourceList= self.rm.list_resources() File "C:\Python27\lib\site-packages\pyvisa-1.8-py2.7.egg\pyvisa\highlevel.py", line 1560, in list_resources return self.visalib.list_resources(self.session, query) File "C:\Python27\lib\site-packages\pyvisa_py-0.3.dev0-py2.7.egg\pyvisa-py\highlevel.py", line 233, in list_resources for key, st in sessions.Session.iter_valid_session_classes()], []) File "C:\Python27\lib\site-packages\pyvisa_py-0.3.dev0-py2.7.egg\pyvisa-py\usb.py", line 206, in list_resources serial_number=dev.serial_number, AttributeError: 'Device' object has no attribute 'serial_number'

[MatthieuDartiailh]

What version of PyUSB are you using ? Pyvisa report the version as not being available, but the usb module should have a version string and serial number property was added 4 years ago, so save if you use a old version I don't get how you can end up with that issue.

[marcDesm2]

"pip list" reports that I have pyusb (1.0.0a2) installed

[marcDesm]

Complete list from pip list

C:\Users\marc>pip list DEPRECATION: The default format will switch to mns) in your pip.conf under the [list] section altgraph (0.15) dis3 (0.1.2) enum34 (1.1.6) future (0.16.0) libusb1 (1.6.4) macholib (1.9) matplotlib (1.4.3) numpy (1.9.2) pefile (2017.11.5) PIL (1.1.7) pip (9.0.1) py2exe (0.6.9) PyAudio (0.2.8) pydub (0.16.6) pyftpdlib (1.5.3) PyInstaller (3.3.1) pyparsing (2.0.3) pyserial (3.4) python-dateutil (2.4.2) pyusb (1.0.0a2) pyvisa (1.8) PyVISA-py (0.2) pywin32 (221) pywinusb (0.4.2) scipy (0.16.0) setuptools (16.0) six (1.9.0)

[MatthieuDartiailh]

The version of pyusb on PyPI is 1.0.2. Could you update ?

[marcDesm]

I ran this (BTW, is say something has been deprecated, is it pyusb?)

C:\Users\marc>pip install --upgrade pyusb Collecting pyusb Downloading pyusb-1.0.2.tar.gz (54kB) 100% |################################| 61kB 183kB/s Installing collected packages: pyusb Found existing installation: pyusb 1.0.0a2 DEPRECATION: Uninstalling a distutils installed project (pyusb) has been deprecated and will be removed in a future version. This is due to the fact that uninstalling a distutils project will only partially uninstall the project. Uninstalling pyusb-1.0.0a2: Successfully uninstalled pyusb-1.0.0a2 Running setup.py install for pyusb ... done Successfully installed pyusb-1.0.2

A check shows that the new version is installed

C:\Users\marc>pip list DEPRECATION: The default format will switch to columns in the future. You can use --format=(legacy|columns) (or define a format=(legacy|colu mns) in your pip.conf under the [list] section) to disable this warning. altgraph (0.15) dis3 (0.1.2) enum34 (1.1.6) future (0.16.0) libusb1 (1.6.4) macholib (1.9) matplotlib (1.4.3) numpy (1.9.2) pefile (2017.11.5) PIL (1.1.7) pip (9.0.1) py2exe (0.6.9) PyAudio (0.2.8) pydub (0.16.6) pyftpdlib (1.5.3) PyInstaller (3.3.1) pyparsing (2.0.3) pyserial (3.4) python-dateutil (2.4.2) pyusb (1.0.2) pyvisa (1.8) PyVISA-py (0.2) pywin32 (221) pywinusb (0.4.2) scipy (0.16.0)

Then if I run "python -m visa info" I get the same "USB INSTR: Available via PyUSB (N/A)" . I'm assuming from your previous email that the presence of "N/A" is a bad thing. I'm on my home machine, and I don't have the USBTMC power supply to try out with PyVisa. But I assume I still have the problem.

**C:\Users\marc>python -m visa info Machine Details: Platform ID: Windows-7-6.1.7601-SP1 Processor: Intel64 Family 6 Model 23 Stepping 10, GenuineIntel

Python: Implementation: CPython Executable: C:\Python27\python.exe Version: 2.7.10 Compiler: MSC v.1500 32 bit (Intel) Bits: 32bit Build: May 23 2015 09:40:32 (#default) Unicode: UCS2

PyVISA Version: 1.8

Backends: ni: Version: 1.8 (bundled with PyVISA)

1: C:\Windows\system32\visa32.dll:

     found by: auto
     bitness: 32
     Vendor: National Instruments
     Impl. Version: 17825792
     Spec. Version: 5244672
  #2: C:\Windows\system32\visa32.dll:
     found by: auto
     bitness: 32
     Vendor: National Instruments
     Impl. Version: 17825792
     Spec. Version: 5244672

py: Version: 0.2 ASRL INSTR: Available via PySerial (3.4) TCPIP INSTR: Available USB RAW: Available via PyUSB (N/A). Backend: libusb10 USB INSTR: Available via PyUSB (N/A). Backend: libusb10 GPIB INSTR: Please install linux-gpib to use this resource type. No module named gpib TCPIP SOCKET: Available**

[MatthieuDartiailh]

The first deprecation warning you get may mean that even after uninstalling pyusb some old parts are left behind. Try to go to the Lib/site_packages folder of your Python installation and remove anything related to pyusb manually and then re-install using pip.

[marcDesm]

I deleted a couple of folders in Lib/site_packages and reinstalled using pip. Seems like the "N/A" is gone. I'll try it on my work computer tomorrow. BTW, the work computer has got pip blocked and I need to installed from a setup.py l which I download. Is running "python setup.py install" the same you think?

C:\Users\marc>python -m visa info Machine Details: Platform ID: Windows-7-6.1.7601-SP1 Processor: Intel64 Family 6 Model 23 Stepping 10, GenuineIntel

Python: Implementation: CPython Executable: C:\Python27\python.exe Version: 2.7.10 Compiler: MSC v.1500 32 bit (Intel) Bits: 32bit Build: May 23 2015 09:40:32 (#default) Unicode: UCS2

PyVISA Version: 1.8

Backends: ni: Version: 1.8 (bundled with PyVISA)

1: C:\Windows\system32\visa32.dll:

     found by: auto
     bitness: 32
     Vendor: National Instruments
     Impl. Version: 17825792
     Spec. Version: 5244672
  #2: C:\Windows\system32\visa32.dll:
     found by: auto
     bitness: 32
     Vendor: National Instruments
     Impl. Version: 17825792
     Spec. Version: 5244672

py: Version: 0.2 ASRL INSTR: Available via PySerial (3.4) TCPIP INSTR: Available USB RAW: Available via PyUSB (1.0.2). Backend: libusb1 USB INSTR: Available via PyUSB (1.0.2). Backend: libusb1 GPIB INSTR: Please install linux-gpib to use this resource type. No module named gpib TCPIP SOCKET: Available

[MatthieuDartiailh]

Yes running setup.py would be equivalent but be sure to remove any left over from the previous install.

[MatthieuDartiailh]

I actually played today a bit with USB on windows and found some interesting things. One reason you may be unable to read the serial number is because the right driver is not installed for your device (the USBTMC driver of NIVISA does not work with libusb). You can use http://zadig.akeo.ie/ to actually install the WinUSB driver in its place but note that you won't be able to use NI after that (you will have to first fully uninstall the driver for the instrument).

[marcDesm]

Oh, so it's not sufficient to have "C:\Windows\System32\libusb-1.0.dll" ... this library needs a the "WinUSB" driver? OK I'll look into it. I'm not sure if I can run an full exe on the company PC however (such as zadig). I'll see if there is a more manual way of installing "WinUSB".

[MatthieuDartiailh]

The point is that you need to somehow specify which usb driver to use for the instrument as the one set-up by NI-VISA cannot be used as backend by liusb. This is similar to the udev configuration on Linux it seems. Zadig is just a convenient way to do this, but it may be possible to do it manually.

[marcDesm]

Is this the driver in question?

https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/winusb-installation

[MatthieuDartiailh]

It may very well be so. If you open the windows device manager, your instrument should indeed appear as a generic usb device (at least it was the case for me).