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IO Libraries Suite: Why does my Keysight USB instrument appear disconnected when NI-VISA is also installed on Windows Vista?

IO Libraries Revisions: Suite 15.0 and Suite 15.0 LXI compliant Update

Note: this issue only affects Windows Vista PC’s. This situation has been resolved in IO Libraries Suite 15.1

Upgrade to IO Libraries Suite 15.1, or later, to fix this problem.

If the National Instruments driver is associated with the USB device, the USB driver vendor field in Keysight Connection Expert Properties Pane will be blank.

In this case, the Connection Expert shows the USBTMC device in the failed state and the device cannot be used by the Connection Expert or by a VISA program that was built to explicitly use Keysight VISA (linked with agvisa32.dll). It can be used by a normal VISA program (one linked with visa32.dll) and the device will appear in NI-MAX. The VISA Open Report will indicate that the device is managed by NI-MAX and is usable in a VISA program.

If you need to change the USBTMC driver associated with a device, you must do it for each device you wish to change. From the Windows device manager, right click on the device you wish to change and select ‘Update Driver Software…’. Choose ‘Browse my computer for driver software’ then choose ‘Let me pick from a list of device drivers on my computer’. From that list select the driver you desire and then click ‘Next’ to install the driver. You may be asked to reboot when you make this change.

  • If you choose the NI driver, your device will be visible in NI-MAX and will work with normal VISA programs. The device will appear as failed in Keysight Connection Expert.
  • If you choose the Keysight driver, your device will not be visible in NI-MAX and it will not work with a normal VISA program. The device will be visible and connected in Keysight Connection Expert.

Last Updated: 05January, 2009

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