In most cases PyVISA will be able to find the location of the shared visa library. If this does not work or you want to use another one, you need to provide the library path to the VisaLibrary or ResourceManager constructor:
>>> visalib = VisaLibrary('/path/to/library')
>>> rm = ResourceManager('Path to library')
You can make this library the default for all PyVISA applications by using a configuration file called .pyvisarc (mind the leading dot) in your home directory.
|Windows 2000, XP and 2003||<root>\Documents and Settings\<username>|
|Windows Vista, 7 or 8||<root>\Users\<username>|
|Mac OS X||/Users/<username>|
|Linux||/home/<username> (depends on the distro)|
For example in Windows XP, place it in your user folder “Documents and Settings” folder, e.g. C:\Documents and Settings\smith\.pyvisarc if “smith” is the name of your login account.
This file has the format of an INI file. For example, if the library is at /usr/lib/libvisa.so.7, the file .pyvisarc must contain the following:
[Paths] VISA library: /usr/lib/libvisa.so.7
Please note that [Paths] is treated case-sensitively.
You can define a site-wide configuration file at /usr/share/pyvisa/.pyvisarc (It may also be /usr/local/... depending on the location of your Python). Under Windows, this file is usually placed at c:\Python27\share\pyvisa\.pyvisarc.