The Keysight IO Libraries Suite installer has determined that a 32-bit non-Keysight VISA implementation is already installed on this PC. In this situation, you should install Keysight VISA as Secondary (recommended). Use the preselected settings in the remaining installation steps to install Keysight VISA as the Secondary VISA.

To learn more about Primary/Secondary VISA installations, and how to designate Keysight VISA as Primary, read below.

Primary and Secondary 32-Bit VISA*

When using Keysight VISA with another vendor's VISA on the same PC, one VISA implementation is designated as Primary, and the other is designated as Secondary. This Primary/Secondary designation is known as side-by-side mode. In side-by-side mode, Keysight VISA is installed in a secondary location and does not overwrite the other vendor's VISA (the Primary VISA).

In general, 32-bit non-Keysight VISA implementations do not support being operated as the Secondary VISA. This means that you must operate 32-bit Keysight VISA as the Secondary VISA, and the other vendor's VISA as Primary. Following the installation of Keysight IO Libraries Suite, you can find more details on side-by-side mode in the Keysight IO Libraries Suite online help. You can view this help by clicking Documentation > IO Libraries Suite Help from the IO Control icon located in the bottom right corner of your screen.

Choosing Keysight VISA as Primary

You can designate Keysight VISA as Primary, but it will overwrite and disable the other vendor's VISA. To install Keysight VISA as Primary (NOT usually recommended when another vendor's 32-bit VISA is present**), return to the beginning of the installation process and choose the Custom installation option. You will then be given an option to install Keysight VISA as the Primary VISA.

You can also choose to make Keysight VISA Primary at a later date.** To do that, simply choose the Modify/Change option for the Keysight IO Libraries Suite entry in Windows Add/Remove Programs (Programs and Features on some Operating Systems).

*When installing on a 64-bit operating system, the Keysight IO Libraries Suite installs a 32-bit and a 64-bit version of Keysight VISA. When installing on a 32-bit operating system the Keysight IO Libraries Suite installs only a 32-bit version of Keysight VISA. The 64-bit versions of VISA are automatically managed, so no Primary/Secondary designation is needed for the 64-bit versions.

**It is sometimes necessary to install Keysight VISA as Primary, even when another vendor's VISA is present. This is most commonly the case when a software application, such as the Keysight Physical Layer Test System (PLTS), requires that Keysight VISA be Primary in order to run. 

Last Revised: 13April, 2011