User`s guide

28 Agilent VISA User’s Guide
3 Programming with VISA
VISA Resources and Attributes
This section introduces VISA resources and attributes, including:
• VISA Resources
• VISA Attributes
VISA Resources
In VISA, a resource is defined as any device (such as a voltmeter) with
which VISA can provide communication. VISA defines six resource
classes that a complete VISA system, fully compliant with the
VXIplug&play Systems Alliance specification, can implement. Each
resource class includes:
• Attributes to determine the state of a resource or session or to set a
resource or session to a specified state.
• Events for communication with applications.
• Operations (functions) that can be used for the resource class.
Table 4describes each resource class supported by Agilent VISA. See
VISA Resource Classes in the VISA Online Help for a description of the
attributes, events, and operations for each resource class.
NOTE
Although the Servant Device-Side (SERVANT) resource is defined by
the VISA specification, the SERVANT resource is not supported by
Agilent VISA. The SERVANT Resource is intended for advanced users
who need to write code that causes a computer to function as an
instrument rather than as a controller.
Table 4 Resource Classes Supported by Agilent VISA
Resource Class Interface Types Resource Class Description
Instrument
Control (INSTR)
Generic, GPIB,
GPIB-VXI, Serial,
TCPIP, USB, VXI
Device operations (reading,
writing, triggering, etc.).
GPIB Bus
Interface
(INTFC)
Generic, GPIB Raw GPIB interface
operations (reading, writing,
triggering, etc.).