Manual
7
Model 835-M Programmer’s
Manual
V1.1 2011
VISA is
an IO library
used
to develop IO
applicatio
n
s
and instrument
drivers
that
comply
with industry
standards.
It
is recommended
that the
VISA
library be
used
for programming the
signal
generator. The
NI-VISA
and Agilent
VISA libraries
are
similar
implementations of
VISA
and have the
same
commands, syntax, and
functions.
Using Telnet LAN
Telnet
provides
a
means
of
communicating
with the
signal
generator over the
LAN.
The Telnet client, run on
a
LAN connected
computer, will create a login
session
on the
signal
generator. A connection,
established
between
computer
and
signal
generator, generates a
user
interface
display screen
with
“>”
prompts
on the
command
line.
Using
the Telnet
protocol
to
send commands
to the
signal
generator
is similar
to
communicating
with
the
signal
generator over
LAN.
You
establish
a
connection
with the
signal
generator and then
send
or
receive
information
using
predefined
commands. Communication is interactive:
one
command
at a time. The telnet
service is
available on port 18.
Once
a telnet
session
to the
device is established,
the
echo can
be enabled by
typing
SYST:COMM:SOCK:ECHO
ON
Following this
command
a prompt “>>”
should become
visible.
USB
(fully supported from Firmware 0.4.0
upwards)
The
Model
835-M
supports the following
USB
interface
pro
t
o
c
ols:
1) USBTMC class device
via VISA
2)
USBTMC:
the application programming interface
(API)
provided with the instrument
supports
general programming
using
the
USB
interface under Windows operating system.
USB-TMC
Interface Connection and Setup using VISA
USBTMC stands
for
USB Test
& Measurement
Class. USBTMC is
a
protocol
built on top of
USB
that
allows
GPIB-
like communication
with
USB devices. From
the
user's
point of view, the
USB
device
behave
s
just like a
GPIB
device. For
example, you
can use VISA
Write to
send
the *IDN? query and use
VISA Read
to get the
response.
The
USBTMC
protocol
supports service
request,
triggers
and other
GPIB
specific
operations.
USBTMC upgrades
the
physical
layer from
GPIB
to
USB
while maintaining software compatibility
with
existing
software,
such as
instrument
drivers
and any
application
that
uses VISA. This is also
what
the
VXI-11 protocol
provides
for TCP/IP.