Fluke 8024B - Page 33

8024B
2-42.
Not
all
applications
for
temperature
measurement
use
just
one
thermocouple.
The
applications
material
at
the
end
of
this
section
describes
how
to
use
your
8024B
to
sequentially
measure
different
thermocouples
of
the
same
type.
Your
8024B
is
intended
for
use
with
K-type
thermocouples.
If
you
use
another
type
of
thermocouple,
the
measurement
will
be
in
error.
See
the
Temperature
Measurement
Techniques
material
presented
later
in
this
section.
2-43. Level Detector Operation
WARNING
TO AVOID ELECTRICAL SHOCK AND/OR INSTRUMENT DAMAGE, DO
NOT CONNECT THE 8024B TERMINALS TO SOURCES THAT EXCEED THE
FOLLOWING LIMITS WHEN USING THE LEVEL DETECTOR FUNCTION:
COMMON: 500V DC OR 500V AC RMS WITH RESPECT TO EARTH GROUND
V/Q/S: 500V DC OR 500V AC RMS WITH RESPECT TO THE COMMON
TERMINAL.
2-44.
Use
the
level
detector
function
for
sensing
logic
levels
and
other
active
signals
less
than
250V
dc
or
ac
rms
in
amplitude.
Select
the
200
kN
range
on
the
2
function.
The
200
kQ.
range
is
marked
with
a
step
function
symbol
(_F)
on
the
front
panel
of
your
8024B
to
indicate
its
use
in
the
level
detector
function.
The
level
detector
compares
the
input
signal
toa
+0.8V
(nominal)
reference.
There
is
both
audible
and
visual
indication
of
the
results
of
the
comparison.
The
audible
indication
is
a
2
kHz
tone
that
can
be
enabled
by
depressing
the
AC/
DC
switch
or
disabled
by
releasing
the
AC/
DC
switch.
The
visual
indication
is
an
up
and/or
down
arrow
that
appears
on
the
display
above
and/or
below
the
minus
sign
position.
Figure
2-11
shows
the
indications
for
some
typical
input
signals.
Starting
from
left
to
right:
1. The level is above the +0.8V reference so the Aup arrow appears in the display
and the audible tone does not sound.
2.
The
input
level
is
below
the
+0.8V
reference,
but
above
OV.
The
audible
tone
sounds
and
the
Wdown
arrow
appears
in
the
display
but
the
minus
sign
is
absent.
3.
The
input
levgl
is
below
both
the
+0.8V
reference
and
OV.
The
Wdown
arrow
appears,
the
tone
is
audible,
and
the
minus
sign
appears.
4,
The
input
signal
is
very
near
OV.
The
Wdown
arrow
appears,
the
audible
tone
sounds,
and
the
minus
sign
flickers
off
and
on.
5.
The
input
is
a
train
of
pulses
that
pass
above
+0.8V
but
whose
average
value
is
positive.
Each
time
a
pulse
goes
above
+0.8V,
the
Aup
arrow
appears
and
the
audible
tone
is
silent.
Each
time
the
pulse
goes
below
+0.8V,
the
W
down
arrow
appears
and
the
audible
tone
sounds.
The
minus
sign
does
not
appear.
For
a
fast
pulse
train,
both
arrows
will
be
on.
6.
The
input
signal
is
a
sine
wave
whose
positive
peaks
pass
above
+0.8V
but
whose
average
value
is
negative.
The
audible
tone
and
arrows
behave
as
described
in
step
5
and
the
minus
sign
appears
in
the
display.
2-16