AD Instruments
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©Copyright Abacanto Digital SA.
Manual de usuario AD4120ER
13
5. Measuring Methods
BEFORE PROCEEDING WITH MEASUREMENT, READ SAFETY NOTES ON
PAGE 11.
1. Before proceeding with measurement, if symbol appears on the display,
replace with new batteries.
2. Rotate the function switch to the "EARTH VOLTAGE" position and press to
test. Earth voltage will be displayed on the LCD. When the earth voltage is
more than 10V, it may result in errors in earth resistance measurement.
Accurate earth resistance measurement may not be made.
3. Precision earth resistance measurement method:
(1) Connect green, yellow and red test leads to instrument terminals E, P and C
with auxiliary earth spikes P1, C1 inserted into earth "IN A STRAIGHT LINE".
(Fig. 1)
(2) Rotate the function switch to the proper range, then press the push-button
to test and take the reading.
4. Simplified earth resistance measurement method:
(1) This method is recommended where an earth resistance higher
than 10W is measured or where it is not possible to drive auxiliary earth
spikes. An approximate value of earth resistance can be obtained by the
two-wire system as shown in Fig. 2.
(2) Rotate the function switch to the "EARTH VOLTAGE" position and press to
test. Make certain that earth voltage is less than 10V.
(3) First rotate the function switch to "200W " position and press to test.
Read earth resistance. If the display shows "1" (MSD), switch to
"2000W " position and read earth resistance.
(4) The reading obtained (Rx) is an approximate earth resistance value. There
is no need for external shorting since P and C terminals are shorted by using
