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:
sudo su
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'