Agilent Technologies E2094S, User Manual, Page: 129 / 146

Programming via USB
6
Agilent VISA User’s Guide 129
Communicating with a USB Instrument Using VISA
To establish communications with a USB device using VISA, you can
either use the full VISA resource string for the device or use the alias
provided by VISA. Using the alias is recommended, for reasons
described below.
Using the full VISA resource string, a viOpen call would look
something like this:
viOpen( . . .,
"USB0::2391::1031::0000000123::0::INSTR", . . .
);
Following is a summary of the components of this call.
This string uniquely identifies the USB device. The values needed for
the resource string are displayed in a dialog box when the device is
plugged into the computer.
To simplify the way a USB device is identified, Agilent VISA also
provides an alias which can be used in place of this resource string. The
first USB device that is plugged in is assigned a default alias of
UsbDevice1 . Additional devices are assigned aliases of UsbDevice2 ,
UsbDevice3 , etc. You can modify the default alias name at the time a
device is plugged in, or by running Agilent Connection Expert and
changing the properties of the VISA alias.
Table 29 Summary of Full-String viOpen Call
Value Description Data Type
2391 Manufacturer ID 16-bit unsigned integer
1031 Model Code 16-bit unsigned integer
0000000123 Serial Number string value
0 USBTMC Interface
Number 8-bit unsigned integer