HP 3468A - Programming Hints

Instructions are implemented as they are received over the loop interface. in other
words,
the
3468A
will
be
set
to
the
ac
volts
function
before
it
is
set
to
the
lowest range. It will be set to the lowest range before autoranging, etc.
The complete string is sent to the 3468A by loading the string into the Alpha
register and executing the command OUTA:
ALPHA FORTRAIN4T2 ALPHA
XEQ] [ALPHA] OUTA [ALPHA
Programming Hints
When more than one command is sent to the 3468A in one string, the commands
are
executed
as
they
arrive.
Therefore,
it
is
best
to
make
the
trigger
statement
the
last
statement
in
the
string.
In
this
way,
the
3468A
will
be
set
up
for
the
measurement, before the the multimeter is triggered. If you send the command
”“F2F3”, the F3 command is the last one received and will be in effect.
Instructions
sent
to
the
3468A
are
in
the
form
of
7-bit
ASCII
characters.
All
lower
case
letters,
spaces,
commas,
semicolons
and
Carriage
Return,
Line
Feed
(CR,
LF)
are
ignored.
They
may
be
used
to
format
commands
for
easy
readability.
All
null
characters,
Form
Feed,
and
tab
characters
result
in
a
syntax
error
(see
INSTAT
command,
Status
Register).
All
other
characters
and
sequences
not
explicitly
allowed
(see
the
Command
Codes)
will
also
result
in
a
syntax
error.
For
example:
“F
2
Ra
3”
is
the
same
as
“F2R3”
When
a
multicharacter
command
is
received,
if
a
character
is
received
which
does
not
fit
into
the
syntax
of
a
command,
the
command
will
be
aborted
and
a
syntax
error generated.
An attempt is made by the 3468A to process the character as if
it were the first character
of another command.
For example, the command
“FR3”
will
cause
a
syntax
error
(because
the
3468A
does
not
recognize
FR)
but
will then go to range 3, i.e.,R3.
Commands that require arguments, such as the D2 command, are exceptions to
the
above
rules.
Any
ASCII
character
may
be
sent
as
part
of
the
D2
text
message.
Note, however, that the 3468A display recognizes only the lower six bits of the
ASCII code, see Appendix B.