Fluke 8021B Instruction Manual page 24

8021
B
NOTE
The minus sign
(-)
may
flash
momentarily
as the
8021
B
conies out
of an
overrange condition. This
will
most
likely
he seen
in
the
ohms mode
as
the
open
circuit
test
leads are applied
to
an in-range resistance value. If
the
minus
sign
remains on for
in-range
ohms
readings, the
circuit
is
live
(a
negative voltage
is
present
at the input terminals
due
to
charged capacitors,
etc.),
and
incorrect resistance
readings will
he
observed.
2-23,
The
Display has
two
abnormal
status indicators,
one
for
low
battery
power
and
one
for
instrument overrange.
A BT
is
displayed
when
approximately
80%
of the battery's
life
is
exhausted (battery
replacement
is
indicated).
And,
a
"i" followed by three
blanked
digits
is
displayed (decimal point
may
be present) as
an overrange
indication.
This does not
necessarily
mean
that the
instrument
is
being
exposed
to
a
damaging
input
condition.
For
example, when measuring
resistance
an open-input will
cause
an
overrange indication.
NOTE
When
the
8021B
is
powered
with the
A8I
battery eliminator
the"BT'
indicator
may come
on.
However,
instrument operation
will
remain
normal.
2-24.
The
liquid crystal
display used
in
the 8021
B
is
a
rugged and
reliable unit
which
will
give years
of
satisfactory service.
Display
life
can be extended by observing the following
practices:
1.
Protect the display
from extended exposure
to
bright sunlight.
2.
Keep the voltmeter out of high
temperature, high humidity environments, such
as,
the
dash
of
a
car
on
a
hot,
sunny
day.
Otherwise,
the display
may
temporarily
turn
black.
Recovery
occurs
at
normal operating temperature.
3.
Note that
the
display operation
may
be
slowed
in
extremely low temperature
environments.
No
damage
will
occur
to
the
LCD,
but
response time
is
greatly
increased.
Recovery occurs
at
normal
operating temperature,
2-25.
OPERATION
2-26.
The
six
figures,
2-4 through
2-9,
each
illustrate
one
of the six
measurement
functions of the
Model 802
IB.
Each
figure has
two
parts.
The
lop part
shows your
802
IB
as
it
should look
when
ready
to
perform
that
type of
measurement. The bottom
part of the
figure
lists, in
sequential order, the steps
you
should perform
to
make
that type of
measurement with your 8021
B.
To
operate your 8021
B
turn
to
the
operation
figure
corresponding to the
measurement
function desired
and perform
the steps
listed in
the
figure.
Operate
the
Model 802 IB
in
accordance with
the
input
Overload
Protection
and
the
Input Connections to
COMMON
portions of
the
Operating Notes presented
earlier in
this
section.
2-8