Fluke 8505A - Page 17

8505A
OHMS
AUTO
MANUAL/
EXTERNAL
AUTO
i
t
Select the
OHMS function
to
make resistance measurements (OHMS annunciator lights). The-02A
Ohms
Converter must
be
installed. Eight resistance ranges are
available:
100 MO, 10 MO, 1 MO,
lOOkO,
10 kO,
1 kO,
1000
and
100.
NOTE
Either
two-wire
or
four-wire resistance measurements can
be
made. Refer to Measurement
Terminals and Controls.
The AUTO (trigger) push button selects the Auto Trigger mode. A flashing SAMPLE annunciator
verifies Auto Trigger operation.
Initial use of the
MANUAL/EXTERNAL push button disables the Auto Trigger mode (SAMPLE
annunciator stops flashing), enables the front panel Manual Triggering mode, and
arms
the
External T riggering mode. Each succeeding use of the MANUAL/EXTERNAL push button
triggers
a
new
measurement: any reading already in progress
is
aborted and the new reading begun
immediately. The SAMPLE annunciator verifies that
a
measurement has been triggered
by
flashing
once,
or several
times
(if the sample-per-reading
setting
is greater than
7,
2 exponent 7
—
128
samples). An external trigger applied through the rear panel external
trigger
jack
similarly
commands a new
reading.
An external trigger applied
simultaneously withafront pane! manual
trigger will be
ignored. AUTO
must
be
pushed to reenter
the Auto Triggering mode.
AUTO RANGE toggles into/out of the Autoranging mode, changing the
existing range if necessary.
When enabled
(AUTO annunciator lighted), Autoranging automatically selects a range that
displays the measurement with maximum resolution.
Each use
of
this
manual ranging push button selects the next higher available range,
if AUTO
RANGE was previously activated, use of the uprange push button toggles out of
Autoranging
(AUTO
annunciator off) and steps to the next higher range. No range change
is effected if the
multimeter is already in the highest range.
Use
of the down-range push button causes the multimeter to toggle out
of Autoranging (AUTO
annunciator
off) and assume the next
lower
available range. Each successive use of the
down-
range
button selects the next lower range. This push button has no effect once the
multimeter is in
the lowest available range.
Figure
2-2.
Front Panel Push Buttons (cont)
2-9