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PyVISA

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Manatee

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Apr 1, 2011, 11:29:10 AM4/1/11
to
I have unpacked the PyVISA files into the Python/lib/site-packages dir
and from the IDLE GUI I get and error

import visa

Traceback (most recent call last):
File "<pyshell#25>", line 1, in <module>
import visa
ImportError: No module named visa

There must be more to just putting the files in the correct directory.
Need help configuring PyVISA to work.
My ultimate goal is to control electronic instruments with Python
through visa.

eryksun ()

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Apr 1, 2011, 12:34:58 PM4/1/11
to
On Friday, April 1, 2011 11:29:10 AM UTC-4, Manatee wrote:
> I have unpacked the PyVISA files into the Python/lib/site-packages dir
> and from the IDLE GUI I get and error
>
> import visa
>
> Traceback (most recent call last):
> File "
> ", line 1, in <module>
> import visa
> ImportError: No module named visa
>
>
> There must be more to just putting the files in the correct directory.
> Need help configuring PyVISA to work.
> My ultimate goal is to control electronic instruments with Python
> through visa.

If you're on Windows, they have a win32 executable installer available on SourceForge. Otherwise you can just easy_install the egg.

http://sourceforge.net/projects/pyvisa/files/PyVISA/1.3/

You'll also need a VISA library (.dll or .so file) for your GPIB adapter.

Günther Dietrich

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Apr 1, 2011, 2:05:55 PM4/1/11
to
Manatee <markr...@aol.com> wrote:

>I have unpacked the PyVISA files into the Python/lib/site-packages dir
>and from the IDLE GUI I get and error
>
>import visa
>
>Traceback (most recent call last):
> File "<pyshell#25>", line 1, in <module>
> import visa
>ImportError: No module named visa
>
>
>
>There must be more to just putting the files in the correct directory.

Yes, there is more:

- DON'T unpack the files into any site-packages folder. If you already
have done it, remove them.
- Unpack the PyVISA archive to any other folder.
- On the command line, change into the PyVISA folder. There you should
find - among others - the two files setup.py and setup.cfg (at least
if you use PyVISA-1.3.tar.gz).
- Now, it depends on what variant of python you use and want to install
PyVISA for and on the configuration of your PYTHONPATH rsp. sys.path
and the folders they point to.
You can simply try: 'sudo python ./setup install'
If you are lucky, that's it. If not, you have to decide, where the
installation script has to put the files to. For example, for my
python 2.6, I chose
'/Library/Frameworks/Python.framework/Versions/2.6/'. In this path,
there is a folder 'lib/site-packages', which is pointed to by
sys.path, and where .pth files are evaluated.
- Edit the file setup.cfg. Near the end, in section '[install]', you will
find the line 'prefix=/usr'. Replace the '/usr' by your chosen path.
- Save the file and retry the install (see above).

Best regards,

Günther

Manatee

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Apr 1, 2011, 3:40:23 PM4/1/11
to
On Apr 1, 2:05 pm, "Günther Dietrich" <gd.use...@spamfence.net> wrote:

Well, ok, I'll try some of that. But I am running window 7, not Linux.
The "sudo" command sounds like Linux.

eryksun ()

unread,
Apr 1, 2011, 4:05:55 PM4/1/11
to
On Friday, April 1, 2011 3:40:23 PM UTC-4, Manatee wrote:
>
> Well, ok, I'll try some of that. But I am running window 7, not Linux.
> The "sudo" command sounds like Linux.

Again, there's a win32 exe installer available here:

http://sourceforge.net/projects/pyvisa/files/PyVISA/1.3/PyVISA-1.3.win32.exe/download

If your account is a standard user and the installer doesn't load a UAC prompt, you'll probably have to right-click it and choose to "Run as administrator".

Manatee

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Apr 1, 2011, 4:22:03 PM4/1/11
to
On Apr 1, 4:05 pm, "eryksun ()" <eryk...@gmail.com> wrote:
> On Friday, April 1, 2011 3:40:23 PM UTC-4, Manatee wrote:
>
> > Well, ok, I'll try some of that. But I am running window 7, not Linux.
> > The "sudo" command sounds like Linux.
>
> Again, there's a win32 exe installer available here:
>
> http://sourceforge.net/projects/pyvisa/files/PyVISA/1.3/PyVISA-1.3.wi...

>
> If your account is a standard user and the installer doesn't load a UAC prompt, you'll probably have to right-click it and choose to "Run as administrator".

Aaaaahhhhhh... now we are getting somewhere. I had the wrong version.
Ok, let me try accessing a simple instrument.

Manatee

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Apr 1, 2011, 10:24:58 PM4/1/11
to
On Apr 1, 4:05 pm, "eryksun ()" <eryk...@gmail.com> wrote:
> On Friday, April 1, 2011 3:40:23 PM UTC-4, Manatee wrote:
>
> > Well, ok, I'll try some of that. But I am running window 7, not Linux.
> > The "sudo" command sounds like Linux.
>
> Again, there's a win32 exe installer available here:
>
> http://sourceforge.net/projects/pyvisa/files/PyVISA/1.3/PyVISA-1.3.wi...

>
> If your account is a standard user and the installer doesn't load a UAC prompt, you'll probably have to right-click it and choose to "Run as administrator".

Ok, I have the correct version. I can run "from visa import *" and get
no error. How ever when I run this command I get and error:

My_Instrument = instrument("GPIB::5")

Traceback (most recent call last):

File "C:/Users/Rivetmr/MyPythonScripts/My_GPIB.py", line 2, in
<module>
my_instrument = instrument("GPIB::5")
File "C:\Python27_32bit\lib\site-packages\pyvisa\visa.py", line 288,
in instrument
vpp43.parse_resource(resource_manager.session, resource_name)
File "C:\Python27_32bit\lib\site-packages\pyvisa\vpp43.py", line
777, in parse_resource
byref(interface_board_number))
File "C:\Python27_32bit\lib\site-packages\pyvisa\vpp43.py", line
398, in check_status
raise visa_exceptions.VisaIOError, status
VisaIOError: VI_ERROR_INTF_NUM_NCONFIG: The interface type is valid
but the specified interface number is not configured.

My instrument is on GPIB 5 and I can do a *IDN? with another program
and get a response. So I must still have something not configured
correct. Getting closer though :)

eryksun ()

unread,
Apr 1, 2011, 11:03:32 PM4/1/11
to
On Friday, April 1, 2011 10:24:58 PM UTC-4, Manatee wrote:
>
> VisaIOError: VI_ERROR_INTF_NUM_NCONFIG: The interface type is valid
> but the specified interface number is not configured.
>
> My instrument is on GPIB 5 and I can do a *IDN? with another program
> and get a response. So I must still have something not configured
> correct. Getting closer though :)

If you have more than one board, you might need a more complete resource name, such as 'GPIB1::5' for board 1. You can query the available instruments using get_instruments_list(), which calls the VISA library's viFindRsrc function.

P S

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Apr 22, 2011, 8:26:37 PM4/22/11
to
I did a little writeup for setting PyVISA up in Windows. It's not exactly polished, but it can get you through the difficult bits. If you need any additional help, leave comments/questions on my blog.

http://psonghi.wordpress.com/2011/03/29/pyvisa-setup-in-windows/

> On Friday, April 01, 2011 11:29 AM Manatee wrote:

> I have unpacked the PyVISA files into the Python/lib/site-packages dir
> and from the IDLE GUI I get and error
>
> import visa
>
> Traceback (most recent call last):
> File "<pyshell#25>", line 1, in <module>
> import visa
> ImportError: No module named visa
>
>
>
> There must be more to just putting the files in the correct directory.

> Need help configuring PyVISA to work.
> My ultimate goal is to control electronic instruments with Python
> through visa.


>> On Friday, April 01, 2011 2:05 PM GüntherDietrich wrote:

>> Yes, there is more:
>>
>> - DON'T unpack the files into any site-packages folder. If you already
>> have done it, remove them.
>> - Unpack the PyVISA archive to any other folder.
>> - On the command line, change into the PyVISA folder. There you should
>> find - among others - the two files setup.py and setup.cfg (at least
>> if you use PyVISA-1.3.tar.gz).
>> - Now, it depends on what variant of python you use and want to install
>> PyVISA for and on the configuration of your PYTHONPATH rsp. sys.path
>> and the folders they point to.
>> You can simply try: 'sudo python ./setup install'

>> If you are lucky, that is it. If not, you have to decide, where the


>> installation script has to put the files to. For example, for my
>> python 2.6, I chose
>> '/Library/Frameworks/Python.framework/Versions/2.6/'. In this path,
>> there is a folder 'lib/site-packages', which is pointed to by
>> sys.path, and where .pth files are evaluated.
>> - Edit the file setup.cfg. Near the end, in section '[install]', you will
>> find the line 'prefix=/usr'. Replace the '/usr' by your chosen path.
>> - Save the file and retry the install (see above).
>>
>>
>>
>> Best regards,
>>

>> G??nther


>>> On Friday, April 01, 2011 3:40 PM Manatee wrote:

>>> .
>>>
>>> Well, ok, I will try some of that. But I am running window 7, not Linux.

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