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Table 3-6.
Address
Codes.
ASCII
CODE
CHARACTER
BINARY CODE
OCTAL CODE
Listen
Address
Talk
Address
Jumper
-+
A5
A4 A3
A2 A1
b7 b5
b5
b4
b3 b2 b1
Listen
Talk
SP
:,
#
$
7o
1
(
l
I
0
1
2
3
4
5
6
7
8
I
;
(g'
A
I
D
E
F
G
H
I
J
K
L
M
N
o
P
o
R
S
T
U
W
X
z
t
I
00000
0000'l
00010
00011
00100
00101
00110
00111
01000
0100'l
01010
01011
01100
01101
01110
01111
10000
1000'l
10010
10011
10t00
10101
10110
10111
11000
11001
11010
11011
11100
11111
11110
See
note
below
040
100
M1 101
o42
102
043 103
o44
104
045
105
046 106
u7
'to7
050
110
o51
111
o52
't12
o53 1 13
054
114
055
115
056
116
057
117
060 120
061 121
62
122
063
123
064
124
065
125
066 126
067
'127
o70 130
o71 131
o72
132
073 133
o74
134
o75 135
076 136
Model3490A
Note:
Only first five
bits
of
binary code are
given,
and
these
bits
are
the
same for
both listen
and
talk
addresses.
Sixth
and
seventh
bits
determine
whether address
is listen
(011
or
talk
(1O).
ever,
it cannot
be returned to local
during output of a
reading.
If
REN
goes
HIGH then
LOW again while a
r''
reading output
is in progress,
the 3490A
will
stay
in
remote. In
order
to
return to local, then, REN must
be
HIGH
when no
reading
output
is
in progress.
The 3490A
may
also
be returned
to
local by turning its
power
off
and
back on
again.
If
the 3490A is
returned
to local
by
setting
REN
HIGH,
but
is not
unaddressed
to talk, it
will
continue
to
output
readings. If there
is a listener
such
as
a
9800
series
calculator
on
the
bus that is
addressed
to
listen
but is
not
able to
receive
data,
the 3490Awill
stop
sampling,
since
it
cannot
output
data.
This
condition
may
appear
to
be
a failure,
since the 3490A
would
typically
be
expected
to continue
sampling and no
longer
be
under
program
control.
3-108.
Remote
Program
Sequence. The order
ofremote
programming
is not
important
except
that it
must end
with the
E
command
to execute
the
program.
The
191-ul
programming
sequence
is
one alpha identifier
followed
by
one
digrt.
For
example,
the
progam
F2R4S1T2MlE
selects
AC volts,
l0V
range,
Sample/
Section III
Hold off, Next
External Trigger,
Addressed Multi with
'j
Output
(see
Table
3-7).lf it is necessary
to
change
only
might
be R3E. In
other words,
program
data
will
remain
stored
as
long as the instrument is in
remote control,
unless
changed
by a subsequent programming
data.
if
more than
one
alpha identifier or
digit
is sent, the last
valid
identifier
or digit
will be stored.
For
example,
FRl5T20SMF3E
will
be accepted
as
R5T@F3E. Para-
graph
3-l3l
gives
a
programming
example
using
the
-hp-
9820A
Calculator
as the controller
and
printer.
The
power
line switch cannot
be
programmed.
$109.
Trigger
Source
Program. The following
para-
graphs
explain
the trigger
source codes shown
in
Table
3_7.
3-110.
T0,
Internal
Sample Rate.
The 3490A
releases
the
Hold line
when ready for
a
new
measurement
to
be
taken, and the
instrument
is triggered according to the
internal sample
rate. If
the front
panel
Sample
Rate
control is set
to the
Hold
position,
it will not sample
3-9