Connecting over USB

[AngusEason]

Hi there,
I am trying to use this library to read voltage and current information over USB. However, when I run it I get the following error:

Trying to auto-detect USB device
Traceback (most recent call last):
  File "c:\Users\AngusEason\Desktop\Programming power supply\SPD3303X.py", line 9, in <module>
    with SPD3303X.usb_device() as dev:
  File "C:\Users\AngusEason\AppData\Local\Programs\Python\Python310\lib\site-packages\spd3303x\__init__.py", line 106, in __enter__
    raise Exception("No device found")
Exception: No device found

I believe it is a driver issue where I do not have all the required prerequisites. What drivers, versions, or other software is required to be installed for this to work?

[AngusEason]

Found the issue. In the enter function when it attempts to auto-detect the USB device it looks for 'SPD3XID' in the resources list. However, for my system the address was 'USB0::0xF4EC::0x1430::SPD3XJFQ6R5257::INSTR'. Changing it to search for 'SPD3X' solved the issue.

    def __enter__(self):
        rm = pyvisa.ResourceManager("@py")
        if self._visa_rscr is None:
            logger.debug("Trying to auto-detect USB device")
            resources = rm.list_resources()
            for res_str in resources:
                if "SPD3XID" in res_str:
                    self._visa_rscr = res_str
            if self._visa_rscr is None:
                raise Exception("No device found")

[geissdoerfer]

Thanks for reporting. Could you please check if the code I just pushed to the fix_specificer branch works for your device?

[AngusEason]

That code does not fix it, however if you just remove the "any" it does. e.g.
if (dev_spec in res_str for dev_spec in ["SPD3XID", "SPD3ID"]):

[geissdoerfer]

Oh, I just noticed that I had apparently misread your resource specifier. I fixed it on the fix_specifier branch, using the solution you suggested in your second comment. This should work for both device types. Please try again.

That code does not fix it, however if you just remove the "any" it does. e.g. if (dev_spec in res_str for dev_spec in ["SPD3XID", "SPD3ID"]):

That's not a good idea because it will always evaluate True no matter what's in res_str.

[geissdoerfer]

Hi @AngusEason, could you help me and quickly check if the code on the fix_specifier branch works with your device?

[Heftie]

i did not work correctly for me (branch fix_specifier). Seams that the issue comes from pyvisa or the "@py". Below I have my debugged code snippets: and the console log output.

def __enter__(self):
        rm = pyvisa.ResourceManager("@py")
        if self._visa_rscr is None:
            logger.debug("Trying to auto-detect USB device")
            resources = rm.list_resources()
            logger.debug(resources)
            for res_str in resources:
                if "SPD3X" in res_str:
                    self._visa_rscr = res_str

Trying to auto-detect USB device
('ASRL3::INSTR',)

def __enter__(self):
        rm = pyvisa.ResourceManager()
        if self._visa_rscr is None:
            logger.debug("Trying to auto-detect USB device")
            resources = rm.list_resources()
            logger.debug(resources)
            for res_str in resources:
                if "SPD3X" in res_str:
                    self._visa_rscr = res_str

Trying to auto-detect USB device
('USB0::0xF4EC::0x1430::SPD3XJFC7R0760::INSTR', 'ASRL3::INSTR')

The SP3X change does work for me in that way. I would suggest to remove the "@py" from the pyvisa.ResourceManager.

[geissdoerfer]

OK thanks for checking. I won't have access to the device in the foreseeable future so can't test your suggestions.