HP 54501A - Page 48

Figure
3-1
shows
a
breakdown
of
an
example
<
program
message
>.
There
are
a
few
key
items
to
notice:
1.
A
semicolon
separates commands
from
one
another.
Each
<
program
message
unit
>
serves
as
a
container
for
one
command.
The
<
program
message
unit
>
s
are
separated
by
a
semicolon.
2.
A
<
program
message
> is
terminated
by a
<
NL
>
(new line), a
<
NL
>
with
EOI
asserted,
or
EOI
being
asserted
on
the
last
byte
of
the
message.
The
recognition
of
the
<
program
message terminator
>,
or
<
PMT
>,
by
the
parser
serves
as
a signal
for
the
parser
to
begin
execution
of
commands.
The
<
PMT
>
also
affects
command
tree
traversal
(see
the
Programming
and
Documentation Conventions
chapter).
3.
Multiple
data
parameters
are
separated by
a
comma.
4.
The
first
data
parameter
is
separated
from
the
header
with
one
or
more
spaces.
5.
The
header
MEAS:SOURCE
is
a compound
header.
It
places
the
parser
in the
measure
subsystem until
the
<
NL>
is
encountered.
Message
Communication
and System Functions
HP
54501A
3-6
Programming