-11-
E5
：
Variation due to contact electrode resistance
4. Soil resistivity (ρ) is measured by 4-
probe
method (
ex:
Wenner method):
An
AC current
I
runs
between
E
earthing
probe
and
C
(H)
current
electrode. The potential difference
V
between
P
S
voltage
electrode and
ES
auxiliary earthing
probe
, the potential
difference
V
is
divided by AC current
I
to give
earth resistance
R
.
With
probe
separation
distance
a
, soil resistivity can be
determined
according
to
formula
ρ=2πaR(Ωm)
.
T
he
probe
distance of
C
(H)
-
P
(S)
is equal
to
P
(S)
-
ES
(both
=
a) for
W
enner method. In order to
simpl
ify
the
calculation, make electrode distance
a
much
more
than
probe
embedding depth
h
(
generall
y,
a
>20
h
, as shown
below
).
VI. Operation Methods
1
．
Switch On/Off
Rotate
FUNCTION
rotary switch to switch on and off.
The
rotary
switch button
is in position
“
OFF
” for shut-off. The Tester has no auto
shut-off function
---
shut it off after usage
to prevent unwanted battery
drainage
.
2
．
Battery Voltage Check
A
fter switch on, if LCD displays low battery voltage
icon
"
”
，
which indicates that battery voltage is low, replace
batter
ies
in
accordance
with instructions. Adequate battery power
can ensure
accuracy of measurement.
3
．
AC Voltage Measurement
Ac line voltage measurement can
not
exceed 600 V.
Connect P
(S)
and ES interface to test commercial AC
voltage, no need to connect C
(H)
and E interface.
