Re: [Linux-gpib-general] Compatibility layer for pyvisa?

[Alexander H. <ale...@xx...>]

Things start to move here.
Your installation instructions were very useful, Walter, thank you!
I found that I had to add --enable-python-binding to ./configure and add 
PYTHONPATH="/usr/local/lib/python3.7/site-packages/" to /etc/profile, 
but eventually I got:

      GPIB INSTR: Available via Linux GPIB (b'4.3.3')
      GPIB INTFC: Available via Linux GPIB (b'4.3.3')

in `python3 -m visa info`. Yay!

I then proceeded to play with `python -m visa shell` and visa_test.py 
and managed to enable and disable the output of my power supply and 
write fancy text to the display.

There are situations in which i get error messages in the kernel ring 
buffer like these though:

        Nov 22 11:53:43 gpib kernel: tnt4882: write bus error

and

        Nov 22 11:41:46 gpib kernel: tnt4882: minor 0 read timed out
        Nov 22 11:41:46 gpib kernel: tnt4882: read timed out

Also, pyvisa often exits with:

pyvisa.errors.VisaIOError: VI_ERROR_SYSTEM_ERROR (-1073807360): Unknown system error (miscellaneous error).

and

pyvisa.errors.VisaIOError: VI_ERROR_TMO (-1073807339): Timeout expired before operation completed.

I haven't figured out yet why that is. Is it obvious what I am doing 
wrong here?

My instruments display things like 'Rmt Addr Err' and 'REM MTA'. Not 
sure yet what these mean, but 'Err' definitely doesn't sound right.

One of my goals is to be able to get screenshots off my scope.
The programming manual says:

Example:

210 CLEAR 707            ! Clear interface buffers.
220 OUTPUT 707;"PLOT"    ! Starts plotter buffering.
230 SEND 7;UNT UNL       ! Clears bus, set ATN line at controller true.
240 SEND 7;LISTEN 5      ! Tells plotter at address 5 to listen.
250 SEND 7;TALK 7        ! Sets 54200A/D to talk mode.
260 SEND 7;DATA          ! Sets ATN line at controller to false
270                      ! so data can be transferred.
280 WAIT 50              ! Wait 50 seconds for transfer to finish
290 !               Note:  If programming, use the SRQ capabilities
300 !                      of the 54200A/D to determine if the transfer
310 !                      is complete. Attempting to program the
320 !                      54200A/D while making a hardcopy dump will
330 !                      cause errors.

How would I go about receiving such a plot with pyvisa or linux-gpib 
directly? Can it be done? A quick web search didn't provide insights.

Thanks,
-Alex

On Sun, Nov 22, 2020 at 05:19:58PM +0100, W wrote:
> Hi Alex
> 
> I followed the same path as you and gave up with these NI-Visa drivers. Now
> I have something working with linux-gpib, pyvisa/pyvisa-py on an old PC
> (Pentium 4)
> 
> A couple of days ago, I described my process to have this software
> installed. If you are interested, you can find it here <https://github.com/daturach/Documentation/wiki/GPIB:-Building-an-instrumentation-lab-with-python-libraries>
> 
> Good luck
> 
> Walter
> 
> On 22.11.2020 12:18, Alexander Huemer wrote:
> > Hi
> > 
> > That looks promising. I actually already had it installed but didn't
> > look at it yet. From the README I figure that it has linux-gpib as a
> > dependency. I'll have to look into it.
> > Thanks for the suggestion.
> > 
> > -Alex
> > 
> > On Sun, Nov 22, 2020 at 10:58:44AM +0100, Roel Jordans wrote:
> > > Hi Alex,
> > > 
> > > You may want to have a look at pyvisa-py.  That seems to work nicely
> > > for me without having to install the NI-VISA drivers.
> > > 
> > > Cheers,
> > >   Roel
> > > 
> > > -----Original Message-----
> > > From: Alexander Huemer <ale...@xx...>
> > > To: Linux GPIB general mailinglist <
> > > lin...@li...>
> > > Subject: [Linux-gpib-general] Compatibility layer for pyvisa?
> > > Date: Sun, 22 Nov 2020 08:57:29 +0000
> > > 
> > > Hi
> > > 
> > > My understanding is this:
> > > * linux-gpib implements drivers for many GPIB interfaces and provides
> > > a
> > >    userspace API on top of that, which is great.
> > > * pyvisa depends on vendor drivers like NI-VISA or the equivalent of
> > >    other vendors.
> > > 
> > > Is this correct?
> > > 
> > > I tried to get NI-VISA working yesterday in order to be able to use
> > > pyvisa with a NI PCI board, on a distribution that they do not want to
> > > support, on a i686 box.  I gave up after some hours, the configure
> > > script they have in there was written by drunk monkeys.
> > > 
> > > So, here is my question: Did anybody consider to make the linux-gpib
> > > drivers available to pyvisa?
> > > 
> > > -Alex
> > > 
> > > [1]
> > > https://www.ni.com/de-at/support/downloads/drivers/download.ni-kal.html#334223
> > > 
> > > 
> > > _______________________________________________
> > > Linux-gpib-general mailing list
> > > Lin...@li...
> > > https://lists.sourceforge.net/lists/listinfo/linux-gpib-general
> > > 
> > 
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