MD 9070 Insulation/Continuity Digital Multimeter
Operation
10
Normal forward voltage drop (forward biased) for a good silicon diode is between 0,400
V to 0,900 V. A reading higher than that indicates a leaky diode (defective). A zero reading
indicates a shorted diode (defective). An OL indicates an open diode (defective). Reverse
the test leads connections (reverse biased) across the diode. The digital display shows
OL if the diode is good. Any other readings indicate the diode is resistive or shorted
(defective).
Earth Continuity Test function
WARNING
This function measures the Resistance values of earth connection and equipotential
bonding in Low Voltage Distribution Systems up to Nominal Voltage (Un) 830V, phase-
to-phase. DO NOT use on Systems with Nominal Voltages above that. Measurements
shall only be carried out on de-energized circuits. The measuring loop is protected by an
HBC 1kV F fuse against accidental extraneous overvoltages.
The LCD icon
used alone throughout in this manual is referred as active
measurements of Earth Continuity Test function through the activation of the
TEST
button
on the meter or on the Remote Probe. Check the fuse before each
. If the fuse is open,
the meter will display “
OPEN
” when the
is being activated at no circuit connection to
the probes. Refer to the maintenance section for fuse replacement.
is
inhibited when the meter beeps and displays “> 2 V” plus
warning against
energized circuit of more than 2 V is being connected, before the
is active.
Connecting to energized circuits when the
is active will produce false results and may
blow the protection fuse and/or damage the instrument. Always check with voltage
functions and remove power from the circuits before carrying out the
.
The results of measurements can be adversely affected by impedances of additional
operating circuits connected in parallel or by transient currents.
Setup
as illustrated below. This function uses measuring currents of
≧
200 mA for 2,199
Ω range and
≧
90mA for 21,99
Ω range measurements, auto-ranging. Press the
RANGE
button momentarily to override auto-ranging and select a range. Press and hold for 1
second or more to resume auto-ranging.
The
is active as long as the
TEST
button is pressed and hold. The
TEST
buttons on
the meter and on the Remote Probe work alike. The Continuity Resistance readings are
shown on the primary display. The RANGE of measuring current is indicated on the
secondary display as “
200 mA
” or “
90 mA
”. The meter further gives a beep sound for
continuity when the active Resistance reading is
“< 2 Ω
”.
Default startup primary display reading is “-.---”. Allow enough
time for a good
measuring result. After the
is released, the last measuring display stays until the next
or a function change.
