problem with module PyVisa

[Jean Dubois]

On 9 nov, 22:14, w... at mac.com wrote:
> On Nov 9, 2012, at 3:43 PM, Jean Dubois <jeandubois... at gmail.com> wrote:
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> > The error may be obvious but finding this file and how to install it
> > is not unfortunately.
> > It seems I have to install it from the National Instruments site but
> > Debian Linux doesn't seem to be supported...
> > and I doubt whether just copying this file will be sufficient to make
> > PyVisa work.
> > I wonder whether there might be another way to communicate via USB
> > with a Keithley programmable power supply using Python.
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> > best regards,
> > Jean
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> > --
> >http://mail.python.org/mailman/listinfo/python-list
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> I've been using pyserial quite successfully to control a USB-to-serial converter.
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> That is, controlling a couple of RS232 serial devices via the USB port through a KeySpan USB-to-Serial converter.
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> Pyserial seems to make communication through the USB port quite transparent, at least on my OS-X system.
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> -Bill

Well, in fact I do have some working scripts using pyserial to control
an older (and more expensive) Keithley sourcemeter in combination with
a USB-to-serial converter.
But the trouble started when buying a cheaper and newer Keithley model
which does not have rs232 but only USB. I noticed they have put an
extra layer above USB called USBTMC
which complicates things further. I followed the instructions at
http://www.home.agilent.com/upload/cmc_upload/All/usbtmc.htm?&cc=BE&lc=dut#3.Copyright%20Notice|outline
and compiled and loaded the usbtmc-driver but I still can't
communicate with the Keithley, hence I started looking for an
alternative using PyVisa...and now I'm stuck

jean