9
A
：
Intrinsic error
E2
：
Variation due to power supply voltage
E3
：
Variation due to
temperature change
E4
：
Variation due to interference voltage change
E5
：
Variation due to contact electrode resistance
4. The soil resistivity (
ρ
) is measured using the 4-pole method (Winner
method): the alternating current I flows between the E ground electrode and
the H current electrode, and the potential difference V between the S voltage
electrode and the FR auxiliary ground electrode is calculated. The potential
difference V is divided by the alternating current I obtains the grounding
resistance value R, the electrode spacing distance is a(m), and the soil
resistivity value is obtained according to the formula
ρ
=2
π
aR(
Ω
m), and the
distance between the HS pitch and the S-FR is equal (both a), that is Wenner
method. For ease of calculation, please make the electrode spacing a much
larger than the buried depth h, generally should meet a> 20h, see the figure
below.
VII. Operation Methods
1
．
Switch On/Off
Turn the function key to the corresponding test position and turn it on.
Turn the function key to the OFF position to turn off the instrument. After
power on, there is "APO" displayed in the lower corner. If it is not operated, it
will be automatically turned off after 15 minutes.
2
．
Battery Voltage Check
After switch on, if LCD displays low battery voltage icon
“
“
，
which
indicates that battery voltage is low, and please replace the battery in time.
