I installed NI-488.2 GPIB driver in my Scientific Linux 5.5, and now it is working~! Thanks very much Mathew!

PS: just curious: is there any alternative solution without having NI firmware involved? 

On Tue, May 24, 2011 at 3:56 AM, Mathew Maher <[log in to unmask]> wrote:
If you're using NI-VISA then you probably need NI-488.2 GPIB driver, not
linux-gpib. Beware, however, NI-488.2 GPIB drivers do not work on Linux
with USB adapters - you'll need a PCI GPIB card.

Mat.

Mathew Maher
Simulation Team Leader
Surrey Satellite Technology Ltd


________________________________

From: [log in to unmask]
[mailto:[log in to unmask]] On Behalf Of
eigenroot
Sent: 24 May 2011 00:25
To: [log in to unmask]
Subject: Errors of instrument control with PyVISA in Scientific Linux
5.5


Hello everyone,

I would like to control a Keithley source meter with PyVISA in the lab.
The operating system is Scientific Linux 5.5, and the Python version is
2.4. I first installed NI-VISA's Linux package
(http://joule.ni.com/nidu/cds/view/p/id/2040/lang/en) which was
compatible with Scientific Linux 5, and then ctypes from
http://python.net/crew/theller/ctypes/ and linux-gpib from
http://linux-gpib.sourceforge.net/. After everything was done
successfully I fired up an interactive Python session, and typed

import visa

No errors. And then I typed

keithley = visa.instrument("GPIB::25")

but got errors:

Traceback (most recent call last):
 File "<stdin>", line 1, in ?
 File "/usr/lib/python2.4/site-packages/pyvisa/visa.py", line 287, in
instrument
   interface_type, _ = \
 File "/usr/lib/python2.4/site-packages/pyvisa/vpp43.py", line 777, in
parse_resource
   byref(interface_board_number))
 File "/usr/lib/python2.4/site-packages/pyvisa/vpp43.py", line 398, in
check_status
   raise visa_exceptions.VisaIOError, status
pyvisa.visa_exceptions.VisaIOError: VI_ERROR_LIBRARY_NFOUND: A code
library required by VISA could not be located or loaded.


Could anyone please help? Thanks very much~!


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