User`s guide

144 Agilent VISA User’s Guide
6 Programming via USB
Although the case of a VISA alias is preserved, case is
ignored when the alias is used in place of the full resource
string in a viOpen call. For example, UsbDevice1,
usbdevice1 and USBDEVICE1 all refer to the same device.
Using the alias, a viOpen call would look something like
this:
viOpen( . . ., "UsbDevice1", . . . );
As you can see, this is much simpler than having to use the
full resource string for a USB device.
Using the alias in a program also makes it more portable.
For example, two identical USB function generators have
different resource strings because they have different serial
numbers. If these function generators are used in two
different test systems and you use the full resource string to
access the function generator in the test program, you
cannot use that same program for both test systems, since
the function generators’ full resource strings are different.
By using the alias in the program, however, you can use the
same program in both test systems. All you need to do is
make sure the same alias is used for the function generator
in both systems.