HP 54501A - Page 96

Common
Commands
5
The
common
commands
are
defined
by
the
IEEE 488.2
standard. These
commands
will
be
common
to
all
instruments
that
comply
with
this
standard.
They
control
some
of
the
basic
instrument
functions,
such
as
instrument
identification
and
reset,
reading
the
learn
(instrument
setup)
string,
how
status
is
read and
cleared,
and how
commands
and
queries
are
received and
processed
by
the
instrument.
Common
commands
can
be
received
and
processed
by the
HP
54501A
whether
they
are
sent
over
the
HP-IB as
separate
program
messages
or
within
other
program messages.
If
an
instrument
subsystem
has
been
selected and
a
common
command
is
received
by the
instrument,
the
instrument
will
remain
in
the selected
subsystem.
For
example,
if
the
program
message
"ACQUIRE:COUNT
1024;
*CLS; TYPE
AVERAGE"
is
received
by
the
instrument,
the
instrument
will
set the
acquire
count
and
type,
and
clear
the
status
information.
This
would
not
be
the
case
if
some
other
type
of
command
were
received
within
the
program message.
For
example
the
program
message
":ACQUIRE:COUNT
1024;
:AUTOSCALE;
:ACQUIRE:TYPE
AVERAGE"
would
set
the
acquire
count,
complete
the
autoscale,
then
set
the acquire
type.
In
this
example
:ACQUIRE
must
be
sent
again
in
order to
reenter
the
acquire subsystem
and
set
the
type.
Refer
to
figure
5-1
for
common
commands
syntax
diagram.
Note
Each
of the
status
registers
mentioned
in
this
chapter
has
an
enable
(mask)
register. By
setting
the
bits
in
the
enable
register
you
can
select the
status
information
you
wish
to
use.
For
a
complete
discussion
of
how to
read
the
status
registers
and
how
to
use
the
status
information
available
from
this
instrument
refer
to
chapter
3.
HP
54501A
Programming
Common
Commands
5-1