Fluke 8021B - 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