HP 3457A - Page 49

3457A
Operation
3-27.
Range
Selection.
The
Auto-Range
feature
automatically
selects
the
appropriate
range
for
the
current
being
measured.
The
Auto-Range
feature
can
be
disabled
by
selecting
Manual
Ranging.
There
are
5
DC
current
ranges
available;
300
uA,
3
mA,
30
mA,
300
mA
and
|
A.
There
are
3
AC
current
ranges
available,
30
mA,
300
mA
and
1
A.
The
maximum
input
current
for
DC
or
AC
inputs
is
1.5
A
peak.
The
default
range
is Auto-Range.
©
To
select
Manual
Ranging
and
maintain
the
present
range
-
Press
the
Blue
SHIFT
key
then
the
{/HOLD
scroll
key.
© To select Manual Ranging and the next higher range - Press the t/AUTO scroll key.
© To select Manual Ranging and the next lower range - Press the |/HOLD scroll key.
¢ To return to Auto-Ranging - Press the Blue SHIFT key then the }/AUTO scroll key.
3-28.
Measurement
Resolution.
Measurement
Resolution
is
changed
by
selecting
the
number
of
digits
dis-
played.
You
can
choose
a
display
of
3
1/2,
4
1/2,
5
1/2
or
6
1/2
digits.
The
1/2
digit
refers
to
the
most
sig-
nificant
digit
which
is
limited
to
a
value
of
0,
1,
2,
or
3.
The
default
number
of
digits
displayed
is
5
1/2
(most significant digit plus 5 digits).
©
To
change
the
number
of
digits
displayed
-
Press
the
DIGITS
DISP
/
P
configuration
key,
enter
the
number
3,
4,
5
or
6
and
press
the
ENT
/
LAST
ENTRY
key.
3-29.
Integration
Time.
The
Integration
time
can
be
changed
to
reduce
measurement
noise
or
to
permit
faster
readings.
The
integration
time
is
dependent
upon
the
power
line
frequency
and
is
expressed
in
num-
ber
of
power
line
cycles
(NPLC).
There
are
six
integration
times
available,
100
PLC;
10)
PLG,.1-PLG,..1
PLC.
005
PLC
and
.0005
PLC.
The
greater
the
PLC
number,
the
quieter
and
more
accurate
the
reading
will
be
and
the
slower
the
measurement
speed.
©
To
select
the
Integration
Time
-
Press
the
NPLC
/
A
configuration
key.
Use
the
[/AUTO
or
|/HOLD
scroll
key
to
display
the
desired
number
and
press
the
ENT
/
LAST
ENTRY
key.
The
Integration
Time
can
also
be
changed
by
pressing
the
NPLC/A
key,
entering
the
desired
number
directly
using
the
MATH
keys
and pressing
the
ENT/LAST
ENTRY
key.
3-30.
Input
Connections.
For
current
measurements,
the
input
current
is
applied
to
the
INPUT
I
and
LO
Terminals,
This
applies
to
both
Front
and
Rear
Terminal
operation.
When
using
the
HP
44491A
Plug-In
as-
sembly,
the
input
is
connected
to
the
I
and
LO
inputs
of
either
channel
8
or
channel
9.
3-31.
Front/Rear
Input
Selection.
The
Input
configurations
are
Front
Terminals,
Rear
Terminals/Scanner
or
Open.
Only
one
input
configuration
(front,
rear,
scanner
or
open)
can
be
selected
at
a
time.
©
To
select
Input
configuration
-
Press
the
TERM
/
M
configuration
key.
Use
the
{/AUTO
or
|/HOLD
scroll
key
to
display
the
desired
input
and
press
the
ENT
/
LAST
ENTRY
key.
The
input
can
also
be
changed
by
pressing
the
TERM/M
key,
entering
the
appropriate
number
using
the
MATH
keys
and
pressing
the
ENT/LAST
ENTRY
key.