Terra Exploration Group EZ Res Pro Manual

Terra EZ ResTM Pro 2/3/4 Probes
Earth R/P Analyzer
Copyright 2016
Terra Exploration Group
Austin, Texas, USA
512-280-9600
www.TexGru.com
Technical User's Guide

CONTENTS
Warning..............................................................................................1
I．Introduction ..................................................................................3
II．Technical Specifications .............................................................4
1. Base Conditions and Working Conditions ............................4
2. General Specification.............................................................4
3. Intrinsic error and performance indicators under base
conditions...................................................................................8
III．Tester Structure .........................................................................8
IV．LCD Display..............................................................................9
V．Measuring Principle..................................................................10
VI.Operation Methods .....................................................................11
1．Switch On/Off....................................................................11
2．Battery Voltage Check........................................................11
3．AC Voltage Measurement ..................................................11
4．Earth Voltage Measurement...............................................12
5．4-wires Precise Earth Resistance Measurement.................13
6．3-Wires Earth Resistance Measurement.............................15
7．2-Wires Simple Measurement............................................15
8．Soil Resistivity Measurement ............................................17
9．Backlight Control ..............................................................18
10．Alarm Settings .................................................................18
11．Data Lock/Storage............................................................18
12．Data Reading/Deletion.....................................................19
13．Data Upload.....................................................................19
VII.
.Battery Replacement ..............................................................19
VIII．Accessories............................................................................20

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Warning
Thanks for your purchase of Terra EZ Res Pro
Digital Earth Analyzer. For best results, thoroughly
read and completely understand this User's Guide.
Thetester conforms toIEC61010indesign, production
and testing.
Underall circumstances,payspecial attention to the
safe use of this device.
Avoid nearby use of high-frequency signalgenerators like mobile
phones to avoidelectrical interference errorsduringdevice operation.
Pay attention towarnings and symbols shown on the device.
Make sure thatdevice andaccessories areingood
working order beforeuse.Do not use if there are broken parts or
exposed areas of test wires. Do not touch probes while
measurement is in progress---risk of electrical shock!!!!
Duringmeasurement, do not touch bareconductors or circuits
undermeasurement.
Beforemeasurement, please set rotary FUNCTION
switch to desired measuring position.
Confirmthatconnector plugofleadshave been completely
inserted into device interface.
Do not expose to Earth Voltage exceeding 600VA.C.orD.C.
between probes and interface as this may seriously damage the
device.

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Do not operate device in the presence of flammables, as a spark
spark could initiate an explosion or fire.
Do not use device if test wires are damaged with uninsulated wire
exposed.
Do not expose the device to high temperatures, high humidity or
condensation.
Do not leave device exposed to direct sunlight
for expended periods to avoid excessive heating of electronics.
Forbattery replacement,remove testingwirefrom device
interface,and make sure that rotary FUNCTION switch
is in “OFF”position.
Dispose of used batteries in an appropriate manner.
When the meterdisplays batterylowvoltagesymbol, replace
batteries.
TheTesterhas noautoshut-offfunction.Uof
Testing complete, turn rotary FUNCTION switch to "Off"
Ifthe Testeris notgoingtobeused foralongperiod,remove
batteries to prevent battery corrosion and damage to the device.
This measuringdevice is onlytobe disassembled,
adjusted and/or andrepaired bydistributor-authorized
personnel---all other use will void warranty.
Risk of severe electrical shock exists through improper
use of this device. Device users must perform all operations
as instructed in this user's guide.

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I．Introduction
The Terra EZ Res Pro is specially designed and
manufactured for measuring earth resistance, soil resistivity and
AC voltage. Utilizing state-of-the-art digital and micro-processing
technology precise earth resistance and soil resistivity
measurements can utilize 2, 3 or 4 probe arrays. The EZ Res Pro
possesses an unique function of wire resistance verification,
anti-interference capability and the ability to adapt to the
environment---all to ensure high precision, high stability and
reliability for prolonged and complicated measurements. The
EZ Res Pro is very effective in locating caves and tunnels as
well as underground water and mineral veins through the use
of electrical resistance tomography to accurately locate desired
subterranean anomalies. The EZ Res Pro is also widely used in
commercial power, telecommunications, oil field applications and
general construction.
The Terra EZ Res Pro is composed of a
host device, monitoring software, testing wires,
communication wires, probes and a carrying case. The large
LCD display of device offers blue back-light for dark conditions
and a digital bar graph for ease of viewing. The Terra EZ Res
Pro can store sets of data of 300 individual readings, allowing
post-analysis via the included Data Collection and Analysis
Software, showing the maximum, minimum, and average
resistivity values. Included are alarm settings and an
alarm indicator as well as historical data access,
reading, preservation, report forms and printing.
The Terra EZ Res Pro Earth Analyzer may also
be called: Precise Earth Resistance Tester, 4-pole
Earth Resistance Tester, 2/3/4-pole Earth Resistance
Tester and/or Soil Resistivity Tester.

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II．Technical Specifications
1. Working Conditions
Influence Description
Working
Conditions
Ambient Temp
15F-105F
Ambient Humidity
＜80%
Working Voltage
9V±1.5V
Auxiliary Earth
Resistance
＜30kΩ
Interference Voltage
＜20V
Interference Current
＜2A
Electrode Distance
when measuring R
a＞5d
Electrode Distance
when measuring ρ
a＞20h
2. General Specification
Function
Measurement of 2/3/4-pole earth resistance, soil
resistivity, earth voltage, AC voltage
Power Supply
DC 9V(6 High Quality Alkaline C Cells 1.5V
continuous standby for 300 hours )
Measurement
Range
Earth Resistance: 0.00Ω-30.00kΩ
Soil Resistivity: 0.00Ωm-9000kΩm
Measuring
Modes Precise 4-probe measurement, 3-probe
measurement and simple 2-probe measurement
Measuring
Methods
Earth Resistance: rated current change-pole
method, measurement current 20mA Max
Soil Resistivity: 4-pole measurement
(Wenner or Schlumberger Arrays))
Earth Voltage: average rectification(between P(S)-ES)
Test Frequency
128Hz/111Hz/105Hz/94Hz(AFC)
Short-circuit
Test Current
AC 20mA max
Open-circuit
Test Current
AC 40V max
Test Voltage
Wave
Sine wave
Electrode
Distance Range
Outside probes can be set up to 330' apart .
Shift
Earth resistance: 0.00Ω-30.00kΩ, automatic shift

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Soil Resistivity: 0.00Ωm-9000kΩm, automatic shift
Backlight
Blue screen backlight, suitable for dim light use
Display Mode
4-digital super-large LCD display, blue screen
backlight
Measuring
Indicator
During measurement, LED flash indicator, LCD count
down display, progress bar indicator
LCD Frame
Dimension
5"×3"mm
LCD Window
Dimension
4.9"×2.6"
Dimension
L×W×H: 8.5"×7.5"×3.75"
Standard Test
Wire
4 wires: red 200 feet, black 200 feet, yellow 100
feet, and green 100 feet
Simple Test
Wire
2 wires: red and black 5.2 feet each
Landscape
Spikes 4 probes: 3/8" x 12"
Measuring Rate
Voltage to ground: about 3 times/second
Earth resistance, soil resistivity: about 5 seconds/time
Measuring
Times
Over 5000 times (Short-circuit test, interval time
should be at least 30 seconds)
Circuit Voltage
Below AC 600V
RS232 Interface
RS232 interface, software supervision, storage
data can be uploaded to computer, saved or printed.
Communication
Wire
One RS 232 Cable
Data Storage
300 measurements, “MEM” icon storage indicator,
flash display “FULL” icon to indicate storage is full
Data Hold
Data hold function: “HOLD” icon display
Data Read
Data read function: “READ” icon display
Overflow
Display
Exceeding measuring range overflow function: “OL”
icon display
Interference
Test
Recognize interference signal automatically, “NOISE”
icon display when interference voltage exceed 5V
Auxiliary
Earthing Test
Can measure auxiliary earth resistance, 0.00KΩ-
30kΩ(100R+rC<50kΩ, 100R+rP<50kΩ)
Alarm Function
When measuring value exceeds alarm setting value,
an alarm will sound.
Battery Voltage
When battery voltage decreases to about 7.5V,
low battery voltage icon will display, indicating
battery replacement is necessary.

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Power
Consumption
Standby: about 20mA (Backlight shut off)
Boot-up and with backlight: about 45mA (25mA
without backlight)
Measurement: about 100mA (Backlight shut off)
Weight
Total weight: 12 lbs. (including package)
Tester: 3.2 lbs (including batteries)
Testing wires: 5.3 lbs
Copper-clad probes (4pcs) 5 lbs
Working
Temperature &
Humidity
15 oF-115 oF, below 80%rh
Storage
temperature &
humidity
-4 oF-140oF, below 70%rh
Overload
Protection
Measuring earth resistance: between interfaces of
C(H)-E、P(S)-ES, AC 280V/3 seconds
Insulation
Resistance
Over 20MΩ (between circuit and enclosure it is 500V)
Withstanding
Voltage
AC 3700V/rms (Between circuit and enclosure)
Electromagnetic
Features
IEC61326(EMC)
Protection Type
IEC61010-1 (CAT Ⅲ300V、CAT IV 150V、Pollution
2), IEC61010-031, IEC61557-1 (Earth resistance),
IEC61557-5 (Soil resistivity), JJG 366-2004
3. Intrinsic error and performance indicators under base
conditions
Category
Measurement Range
Intrinsic Error
Resolution
Earth
Resistance
(R)
0.00Ω-30.00Ω
±2%rdg±3dgt
0.01Ω
30.0Ω-300.0Ω
±2%rdg±3dgt
0.1Ω
300Ω-3000Ω
±2%rdg±3dgt
1Ω
3.00kΩ-30.00kΩ
±4%rdg±3dgt
10Ω
Soil Resistivity
(ρ)
0.00Ωm-99.99Ωm
According to
the precision of
R
(ρ=2πaR
0.01Ωm
100.0Ωm-999.9Ωm
0.1Ωm
1000Ωm-9999Ωm
1Ωm
10.00kΩm-99.99kΩm
10Ωm

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100.0kΩm-999.9kΩm
a:1 m-100m,
π=3.14)
100Ωm
1000kΩm-9000kΩm
1kΩm
Earth Voltage
AC 0.0-600V
±2%rdg±3dgt
0.1V
Note: 1. When rC max or rP max, additional error≤±3%rdg±5dgt.
(rC max: 4kΩ+100R＜50kΩ, rP max: 4kΩ+100R＜50kΩ)
2. When 5V interference voltage, additional error≤±5%rdg±5dgt.
III． Tester Structure
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1. LCD 2. Button area
3. Rotary switch for function selection 4. RS232 interface
5. Interface for testing wires 6. P(S) interface: Voltage probe
7. C(H)interface: Current probe 8. Einterface: Earth probe
9. ES interface: Auxiliary earth probe 10. Standard test wires
11. Auxiliary earthing probes 12. Simple test wires
IV．LCD Display
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1. Progress bar (Dynamic display of testing progress)
2. Alarm symbol (Displayswith open alarm function, flashes when
alarm value is met)
3. Exceed voltage symbol (Displayswhen measured voltage exceeds
30V---use caution and maintain safety)
4. AC symbol
5. Data hold symbol (Press MEM to hold data)
6. Data access symbol (Press MEM for at least 3 seconds to access
data)
7. Data storage symbol (Press MEM to store data)
8. Interference signal symbol (Displayswhen interference voltage
exceeds5V)
9. Low battery symbol (Displayswhen battery voltage falls to 7.5V or
less)
10. Displaysthe group number of stored data and countdown.
11. Interference electrode symbol (Displayswhen interference
exceeds 5v)
12. Measured data
13. Voltage unit symbol
14. Resistance, soil resistivity, length unit symbol (Ω, kΩ, Ωm, kΩm, m)

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V．Measuring Principle
1. Voltage to ground measurement utilizes average value rectification
method.
2. Earth resistance measurement uses fall-of-potential method. AC
constant current I is applied between the measurement object Eearth
probe and C(H) current probe, and calculating the potential
difference Vbetween Eearth probe and P(S) voltage probe,
calculating the earth ground Raccording to formula R=V/I. To ensure test
accuracy,the 4-wires method was developed. To use 4-wires
method,clip ES and E to the same probe during testing. The 4-wires
method can eliminate the influence of contact resistance (usually caused
by dirty probes) between measured earthing body, auxiliary earthing
probes, test clips and/or meter’s input interface. The 4-wires method
can also eliminate influence of line resistance.
3．Maximum Operating Error：Operating error(B) is an error obtained
within the rated operating conditions, and calculated with the intrinsic
error(A), which is an error of the instrument used, and the error(E) due to
variations.
A：Intrinsic error
E2：Variation due to power supply voltage
E3：Variation due to temperature change
E4：Variation due to interference voltage change

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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 Eearthing probe and C(H) current
electrode. The potential difference V between PS 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). The probe distance of C(H)-P(S) is equal to
P(S)-ES (both =a) for Wenner method. In order to simplify the
calculation, make electrode distance amuch more than probe
embedding depth h(generally,a>20h, 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
After switch on, if LCD displays low battery voltage
icon " ”，which indicates that battery voltage is low, replace
batteries in accordance with instructions. Adequate battery power
can ensure accuracy of measurement.
3．AC Voltage Measurement
Ac line voltage measurement cannot exceed 600 V.
Connect P(S) and ES interface to test commercial AC
voltage, no need to connect C(H) and E interface.

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AC voltage measurement refers to general commercial AC
voltage measurement.By determining the difference between earthing
voltage, the meter can be used for testing below 600V AC line voltage.
As shown below: First,connect test wires P(S) with ES interface.
Second,connect test wires with tested line, then rotate FUNCTION
rotary switch to “EARTH VOLTAGE” and start testing, LCD will display
the test results.
4．Earth Voltage Measurement
Earth voltage measurement uses only 2 probes (ES + P).
The meter connects with the earth by using only
testing wires and 2 probes. Other testing wires of meter’s
interface cannot be used to connect with commercial
power line L, N, as breakers may be tripped and serious
damage to tester will result.
Earth voltage measurement cannot exceed 600 V.
As shown below: once meter, probes and testing wires are all
connected, rotate FUNCTION rotary switch to “EARTH VOLTAGE”
and start testing, LCD will display test results.
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5．4-wires Precise Earth Resistance Measurement
For testing earth resistance, first confirm the
earth voltage i.e. the voltage between C(H) and E or
P(s) and ES must under 20V. The meter NOISE
symbol shows when the earth voltage exceeds 5V,
which may produce resistivity measurement error. If
high earth voltage is found, interrupt power
supply causing earth voltage. Confirm the earth
voltage decrease, then test earth resistivity again.
4-wires measurement: The 4-wires method can eliminate the influence
of contact resistance (usually caused by rust) between probes, test clips,
and/or meter’s input interface. The 4-wires method can also eliminate
influence of line resistance. It is much better than 3-wires measurement.
As shown below: Start from probe E, interval 10-30', respectively
insert P(S), C(H) probes deep into the earth in a straight line, and then
connect testing wires (black, green, yellow, red) from E,ES, P(S),C(H)
interfaces corresponding to measured earth electrode E, auxiliary
voltage electrode P(S),auxiliary current electrode C(H).
The distance from probe E to current electrode C(H),
should at least ten times farther than the embedded
depth probe depth (h)
Testing wires cannot be wound together as this will
affect measuring accuracy.
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>10h

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6．3-Wires Earth Resistance Measurement
3-wires measurement: As shown below, short-circuit ES and E interface.
The operation of meter is the same with 4 wires measurement but, the
3-wires method cannot eliminate the influence of line resistance, or the
influence of contact resistance between meter and testing wires or
between testing wires and probes. Oxidation layers on probes must be
removed when measuring.
7．2-Wires Simple Measurement
Using simple 2-wires method for measuring earth
resistance, choose a earthing body which has a small re
value as auxiliary earthing probe, so that the reading value is
more close to the actual value. Buried metal pipes or metal
fire hydrant would be priority auxiliary earthing probes.
d= Probe Depth

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2-wires method: This method is a simple method for measurement
that does not use an auxiliary earthing probe. Use the earth electrode
with the minimal existing earth ground resistance value as auxiliary
earth electrode and connect two simple testing wires (in which C(H)-
P(S), E-ES interfaces are in short circuit). It can make use of metal pipes,
fire hydrants and other metal buried objects, common earthing of
commercial electric power system or lightning protection earth ground
electrode and others to replace auxiliary earthing rods C(H),P(S)---remove
oxide layer on the connection point of the selected metal auxiliary
earthing object when making measurement.
Wire connection is as shown in following figure, and refer to
4-wires measurement for other operations.
2-wires simple method for measurement of earth ground resistance,
its reading on tester is the total value of earth ground resistance value of

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measured earthing object and that of commercial earthing object, that is:
R=RX＋re
In which:
R is the tester reading value;
RX is the earth ground resistance value of measured earthing
object;
re is the earth ground resistance value of common earthing object
like commercial use power system.
Then, the earth ground resistance value of measured earthing
object is: RX=R－re
8．Soil Resistivity Measurement
Soil resistivity ρis a determining factor of earthing resistance of
earthing body. In different types of soil, there is a different soil
resistivity. Even the same kind of soil, due to different temperatures
and water content and so on, the soil resistivity will correspondingly
show a significant change.
Soil resistivity is measured by 4-pole method (ex: Wenner method)
According to formula ρ=2πaR(Ωm) calculating soil resistivity ρ, its
unit is Ωm, in which:
a——probe separation distance
R——soil resistivity between electrode P(S)-ES
4-pole method (Wenner method): Connect testing wires as shown
below, pay attention to the distance between auxiliary earthing probes,
and the embedding depth. Respectively insert C(H), P(S),ES,E
auxiliary earthing rods deep into the earth in a straight line, and then
connect testing wires (red, yellow, green, black) corresponding to C(H),
P(S), ES, Eof interfaces and measured auxiliary earthing probe.
After completing wire connections, rotate FUNCTION rotary switch to “ρEARTH”,
long press “SET” button (about 3 seconds) to enter setting, quickly

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press “SET” button to move the cursor, press “ ”or “ ” button to change
current data value (arange:1m-100m), then press and hold “SET” button to
save the set a value, and return to soil resistivity testing mode. After setting a
value, in soil resistivity testing mode, press the“START” button to start testing.
A countdown display testing process and soil resistivity value is shown when
testing cycle is completed. As shown below, the measured soil resistivity is
53.38Ωm and there are 157 sets of data stored. Press “SET” button, the earth
resistance rC of auxiliary current electrode C(H) and earth resistance rP of
auxiliary voltage probe P(S) will be displayed, then automatically,display will
return to measured soil resistivity ρ.
9．Backlight Control
After startup, press "Light" button to turn backlight on or
off. The backlight function is helpful in dark situations---power
consumption of backlight is about 25mA. It will default to backlight
turned off after each startup.
10．Alarm Settings
After startup, rotate FUNCTION rotary switch to select function,
press button for abrief time to open or shut off alarm function;hold
for about 3 seconds to enter alarm critical value settings, press or
to change current value. Press button tostore and exit. When
measurement value is surpassed, the alarm function will open --- the icon
will flash and an alarm will sound.
In test mode, press button for a brief time to lock current
displayed data, showing , icon and automatically store with
icon, andserial numbers. If storage is full, the tester will display
then press button to remove lock.
As shown in the left figure below: the lockmeasurement data of soil
resistivity is 53.38Ωm, as the 28th group of data storage.
11. Data Lock Storage

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12．Data Reading/Deletion
In test mode, press
data reading, press or
button for more than 3 seconds to enter
button to select reading data
number by step value 1, press or button continually to
select data reading group number by step value 10. When the
current data is earth resistance or soil resistivity, press “SET” button to
read data value rC and rP and button to exit from reading.
If there is no storage data, LCD will display “- - - -”, see the above
figure on right side.
Under data reading status, press button to enter data deletion,
press or to select “NO” or “YES”, selecting “NO and then pressing
“CLR” button for not deleting and return data reading status, selecting
“YES” and then pressing “CLR” button for deleting stored data---it will
show as above right figure after deletion.
Notice: Operating data deletion will delete all the stored data one-
time and cannot be restored. Be sure you want to delete stored data.
13．Data Upload
Stored data can be retrieved via functions explained
above and easily transferred to an optional Interpolated
Data Transfer Spreadsheet supplied by Terra Exploration
Group. The Interpolated Data Transfer Spreadsheet
feeds seamlessly into the optional Voxler Earth Imaging
Software. The Interpolated Data Transfer Spreadsheet
and Voxler Earth Imaging Software are available as a
package from Terra Exploration Group. The Interpolated
Data Transfer Spreadsheet provides the ability to view
Voxler information in 2D or 3D modes.
VII. Battery Replacement
Do not replace batteries around flammable products.
Do not replace batteries during measurement
Pay attention to battery polarity and specification. do not
mix use of new and used batteries to avoid damage to Tester
When the enclosure of Tester is wet, do not open battery
cover
Dispose of used batteries in an appropriate manner.
1. Switch off; makesure that the Tester is in switched-off state.
2. Loosen the four screws on battery cover at the bottom of the
Tester, and remove battery cover.
3. Install new batteries, paying attention to battery polarity
and specification, close battery cover, and re-fasten screws.
4. Switch on Tester for verification and operate normally.