Technical data

Installing Agilent I/O Libraries Suite 2
Agilent Connectivity Guide 41
When you have both Agilent VISA and another vendor's VISA installed
on the same system, you will need to decide whether to let your
programs use the primary VISA or whether to explicitly direct them to
use the Agilent VISA implementation.
Agilent IO Libraries Suite supports the option to install Agilent VISA in
side-by-side mode, which allows Agilent VISA to be used
simultaneously with another vendor's VISA implementation. In
side-by-side mode, Agilent VISA is installed only in a secondary
location and therefore does not overwrite another vendor's VISA if it is
present on the computer.
In general, non-Agilent VISA implementations do not support operation
as the secondary VISA (in side-by-side mode). This means that you
must operate Agilent VISA in side-by-side mode as the secondary
VISA, and the other vendor's VISA as primary.
About primary and secondary VISA:
• VISA programs normally use visa32.dll, which is installed in the
Windows system directory. This is the primary VISA, as defined
by the VISA standard.
• Agilent VISA is implemented in agvisa32.dll, which is also
installed in the Windows system directory.
• If Agilent VISA is installed as primary, the Agilent version of
visa32.dll is installed in the Windows system directory. It simply
forwards all VISA calls to agvisa32.dll.
• If you install Agilent VISA as primary, all files needed to support
side-by-side mode are also installed. This means that if you
subsequently install another vendor's VISA as primary, you can
still use Agilent VISA as secondary.
If Agilent VISA is installed in side-by-side mode (as the secondary
VISA):
NOTE
You do not need to install NI-VISA to use National Instruments GPIB
cards and devices. You can install National Instruments’ NI-488.2 as a
driver for these devices, and avoid the complications of side-by-side
operations.