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National Instruments Corporation
5
VXI-USB Installation Guide
For VXI systems that include VME devices, ensure that the VME devices
are not configured in the upper 16 KB (starting from 0xC000) of the A16
address space. This region is reserved for VXI device configuration
registers, which are used for initializing, configuring, and interacting with
VXI devices. The VXI-USB also uses this region for this purpose.
Note
Also ensure that no VXI devices in your system are configured for logical address 0.
This is the VXI-USB logical address, which you cannot change.
Connecting Cables
Connect the USB cable to a USB connection in your host PC and to the
VXI-USB, as shown in Figure 1-1. You can use any available USB port on
the computer for each device. The VXI-USB has two external ports for
devices. You can connect any other USB devices to any available port on a
VXI-USB, but for best performance, minimize the number of USB
devices/hubs in the system. Adding to the number of devices in the tree
degrades system performance.
Note
Your VXI-USB controller is a Hi-Speed USB device, which means it performs much
faster when connected to a Hi-Speed USB port as described in the USB 2.0 specification.
USB 2.0 ports are often integrated on the motherboard of current computers. National
Instruments recommends using an integrated USB 2.0 port, if available, for optimal
performance. Plug-in boards with USB 2.0 ports are also supported but may not provide
the highest performance. Full-speed (USB 1.
x
) ports are supported as well, but provide
much lower performance. The LINK light (refer to Chapter 1,
Introduction
, in the
VXI-USB User Manual
) on the front panel of your VXI-USB controller indicates your
connection speed.
Software Configuration and Verification
To configure the software and verify the configuration, follow these steps:
1.
Run MAX. You must run the Resource Manager (Resman) every time
the chassis or computer power is cycled, so that your application can
access devices in the VXI chassis. You can also configure MAX to run
Resman automatically at every computer startup by selecting
Tools»NI-VXI»VXI Options
and selecting the appropriate checkbox.
2.
You can also use MAX to interactively configure the National
Instruments hardware in your system. Use the right-click help for
information about the various configuration options. After you finish
configuring the system through MAX, verify the configuration
through the interactive control utility, VISAIC (
Start»Programs»
National Instruments»VISA»VISA Interactive Control
), as
described in Chapter 3,
Developing Your Application
, in the
VXI-USB
User Manual
.
