Small improvements to visa backend

[jenshnielsen]

• Slightly better docs and logging
• Correct the backend name to reflect current pyvisa
• Remove deprecated fallback for visa address with library included
• Let pyvisa figure out the default termination char

[codecov]

Codecov Report

Merging #4219 (454e53f) into master (b302431) will decrease coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #4219      +/-   ##
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- Coverage   67.02%   66.99%   -0.04%     
==========================================
  Files         233      233              
  Lines       31525    31517       -8     
==========================================
- Hits        21130    21114      -16     
- Misses      10395    10403       +8     

[jenshnielsen]

@astafan8 Could you have another look. I made a change to not set the visa termination char unless explicitly given to match pyvisa here https://pyvisa.readthedocs.io/en/1.8/resources.html#termination-characters

[astafan8]

I made a change to not set the visa termination char unless explicitly given to match pyvisa here https://pyvisa.readthedocs.io/en/1.8/resources.html#termination-characters

seems like the right thing to do.

[astafan8]

breaking changes notes are added, so i think it's good to go

[jenshnielsen]

bors merge

[bors]

Build succeeded:

• builddocs (ubuntu-latest, 3.10)
• builddocs (ubuntu-latest, 3.9)
• builddocs (windows-latest, 3.7)
• pytestmin (ubuntu-latest, 3.7)
• pytestmypy (ubuntu-latest, 3.10)
• pytestmypy (ubuntu-latest, 3.7)
• pytestmypy (ubuntu-latest, 3.8)
• pytestmypy (ubuntu-latest, 3.9)
• pytestmypy (windows-latest, 3.10)
• pytestnonlocal (3.7)

[gztony1227]

@jenshnielsen @astafan8 Thank you both for incorporating this fix.
How do you pass down terminator when defining the tek 2012B?

I made terminator as a default argument in my local 2012 driver. kwargs won't be able to pass it down to visa.py right? I don't see visa.py looking for kwargs to determine terminator.

So far I like qcodes being installed and updated on pip. I haven't used it like a repository. So it will take a while for the new version to be pip?

def __init__(self, name: str, address: str,
                 timeout: float = 20, terminator: str = '', **kwargs: Any):
        """
        Initialises the TPS2012.

        Args:
            name: Name of the instrument used by QCoDeS
            address: Instrument address as used by VISA
            timeout: visa timeout, in secs. long default (180)
              to accommodate large waveforms
        """

        super().__init__(name, address, timeout=timeout, terminator = terminator, **kwargs) 

[jenshnielsen]

It would be nice if you can test the changes before we release a new version so we are sure it works.
You can install from the master branch by doing pip install git+https://github.com/QCoDeS/Qcodes.git
Once you are done testing you can then do pip uninstall qcodes and pip install qcodes to get back to the release version.
But if you have the time I would recommend lerning a bit of git to be able to install from a cloned repo

The value will be passed to the instrument with the current __init__ class

If you do TPS2012("name", "address", terminator="\n") terminator will be part of the kwargs dict to the base visa class.
Here it will be avilable via the terminator argument whic is passed to set_terminator. There is no need to explicitly add a terminator argument to TPS2012 unless we need to change the default.

What I would like you to do is.

• install qcodes from source as above
• test if scope = TPS2012('tek', 'ASRL5::INSTR') works
• If that does not work test that scope = TPS2012('tek', 'ASRL5::INSTR', terminator='\n') works

I suspect that number 2 will work since that should be equivalet to what pyvisa does by default

[gztony1227]

Dear Jens @jenshnielsen and Mikhail @astafan8 ,
The version worked well. I used a new environment on a separate PC to clone tttps://github.com/QCoDeS/Qcodes.git with pycharm and tps2012B is connected well.
scope = TPS2012('tek', 'ASRL5::INSTR') works

TPS2012('tek', 'ASRL5::INSTR', terminator='\n') also works.

The line "terminator = None" as default is good.
Please go ahead and release the version when you can. Thank you both very much.

[jenshnielsen]

Thanks @gztony1227 i will go ahead and close the issue then