Sonel MRU-200 Earth Resistance Meter User Manual
- June 14, 2024
- Sonel
Table of Contents
Sonel MRU-200 Earth Resistance Meter
Specifications
- Product Name: Earth Resistance Meter
- Model: MRU-200 / MRU-200-GPS
- Manufacturer: SONEL S. A.
- Address: Wokulskiego 11, 58-100 widnica, Poland
- Version: 2.04
- Date: 11.09.2023
Product Information
The MRU-200 / MRU-200-GPS meter is a modern, easy and safe measuring device designed for measuring earth resistance. It is equipped with various settings and features to ensure accurate measurements and convenient usage.
Product Usage Instructions
Safety
Prior to using the MRU-200 / MRU-200-GPS meter, it is important to
familiarize yourself with the safety guidelines outlined in the user manual.
This will ensure safe and proper operation of the device.
Menu
The meter’s menu provides access to various settings and features. The
following subsections explain some of the key menu options:
Wireless Transmission
This option allows you to enable or disable wireless transmission of
measurement data. Refer to the user manual for detailed instructions on how to
set up and use this feature.
GPS Settings
The GPS settings allow you to configure the GPS functionality of the meter.
This includes setting the time zone, enabling or disabling GPS coordinates
display, and more. Follow the instructions in the user manual to properly
adjust these settings.
**Measurement Settings
**
In the measurement settings menu, you can configure various parameters related to the measurement process:
Mains Frequency
This option allows you to set the mains frequency used during resistance
measurements. Ensure the correct frequency is selected based on your location
and power supply specifications.
Calibration of Measurement Clamps
Calibrating the measurement clamps is essential for accurate readings. The
user manual provides step-by-step instructions on how to calibrate the clamps
properly. Follow these instructions carefully.
Earth Resistivity Settings
The earth resistivity settings menu allows you to adjust parameters
specific to earth resistivity measurements. Refer to the user manual for
detailed instructions on how to configure these settings correctly.
Meter Settings
The meter settings menu provides options for customizing the display and other meter-related settings:
LCD Contrast
You can adjust the LCD contrast to optimize visibility based on your
preferences. Follow the user manual instructions to make the necessary
adjustments.
LCD Backlight
This option allows you to control the backlight of the LCD display. Adjust
the backlight settings according to your needs and lighting conditions.
AUTO-OFF Settings
The AUTO-OFF feature automatically turns off the meter after a specified
period of inactivity to conserve battery power. Configure the AUTO-OFF
settings based on your requirements.
Display Settings
The display settings menu offers options for customizing the information
displayed on the meter’s screen. Follow the user manual instructions to modify
the display settings as desired.
Date and Time
You can set the date and time on the meter using this menu option. Ensure
accurate date and time settings for proper measurement logging and record-
keeping.
Battery Discharging
This option provides information about the battery status and discharging
rate. Refer to the user manual for detailed instructions on interpreting and
utilizing this feature.
Programme Update
The programme update option allows you to update the meter’s firmware when
new versions become available. Follow the instructions in the user manual to
perform a successful firmware update.
Language Choice
You can select your preferred language from the available language options provided by the meter. Follow the user manual instructions to change the language setting.
Information on the Manufacturer
This menu section provides information about the manufacturer, SONEL S. A.,
including their address. It is useful for reference purposes.
Measurements
The MRU-200 / MRU-200-GPS meter offers different measurement modes and techniques:
Measurement of Resistance of Earth Connection and Equipotential Bonding (2P)
This measurement mode allows you to measure the resistance of earth
connections and equipotential bonding using a specific method. Refer to the
user manual for step-by-step instructions on performing measurements in this
mode.
Calibration of the Test Leads (RE3P+ERP-1)
Calibrating the test leads is crucial for accurate measurements. The user
manual provides detailed instructions on how to calibrate the test leads
properly. Follow these instructions carefully to ensure reliable results.
Earth Resistance Measurement with Two-Clamp Method (2C)
This measurement mode utilizes the two-clamp method for measuring earth
resistance. The user manual contains detailed instructions on how to perform
measurements using this method. Follow the provided guidelines for accurate
results.
FAQ (Frequently Asked Questions)
Q: How do I update the firmware of the MRU-200 / MRU-200-GPS meter?
A: To update the firmware, follow the instructions provided in the user manual
under the “Programme Update” section. It will guide you through the necessary
steps to successfully update the firmware.
Q: How can I calibrate the measurement clamps?
A: The user manual includes a dedicated section on calibrating the measurement
clamps. Follow the step-by-step instructions provided in that section to
ensure proper calibration and accurate measurements.
Q: What is the purpose of the AUTO-OFF feature?
A: The AUTO-OFF feature automatically turns off the meter after a specified
period of inactivity to conserve battery power. It helps prolong the battery
life and ensures efficient usage of the device.
USER MANUAL EARTH RESISTANCE METER
MRU-200 MRU-200-GPS
SONEL S. A. Wokulskiego 11 58-100 widnica
Poland Version 2.04 11.09.2023
The MRU-200 / MRU-200-GPS meter is a modern, easy and safe measuring device. Please acquaint yourself with the present manual in order to avoid measuring errors and prevent possible problems related to operation of the meter.
The icon with the meter name is placed next to sections of the text that refer to specific features of the device. All other parts of the text relate to all types of the instrument.
Safety
The MRU-200 / MRU-200-GPS meter has been designed to realize measurements
whose results determine the safety conditions of the installation. Therefore,
in order to provide conditions for correct operation and the correctness of
the obtained results, the following recommendations must be observed: Before
you proceed to operate the meter, acquaint yourself thoroughly with the
present manual
and observe the safety regulations and specifications determined by the
producer. The MRU-200 / MRU-200-GPS meter has been designed for the purpose of
measurements of
earth connection and equipotential bonding, ground resistivity, as well as
clamps current measurements. Any application that differs from those specified
in the present manual may result in a damage to the device and constitute a
source of danger for the user. The device must be operated solely by
appropriately qualified personnel with relevant certificates to realize
measurements of electric installation. Operation of the meter realized by
unauthorised personnel may result in damage to the device and constitute a
source of danger for the user. Using this manual does not exclude the need to
comply with occupational health and safety regulations and with other relevant
fire regulations required during the performance of a particular type of work.
Before starting the work with the device in special environments, e.g.
potentially firerisk/explosive environment, it is necessary to consult it with
the person responsible for health and safety. It is unacceptable to operate
the following: A damaged meter which is completely or partially out of order,
A meter with damaged test leads insulation, A meter stored for an excessive
period of time in disadvantageous conditions (e.g. exces-
sive humidity). If the meter has been transferred from a cool to a warm
environment of a high level of relative humidity, do not realize measurements
until the meter has been warmed up to the ambient temperature (approximately
30 minutes). Before measurements may commence, make sure the test leads are
connected to the appropriate measurement sockets. Do not operate a meter with
an open or incorrectly closed battery (accumulator) compartment or power it
from other sources than those specified in the present manual. The meter’s
inputs are electronically protected from power surge, as a result for example,
of accidental connection to the power supply source: – for all input
combinations up to 276 V for 30 seconds. Repairs may be realized solely by
an authorized service point. The device complies with the following norms; EN
61010-1 and EN 61557-1, -4, -5.
Note: The manufacturer reserves the right to modify the appearance,
accessories and technical data of the meter.
MRU-200 MRU-200-GPS USER MANUAL
5
2 Menu
The menu is available at any position of the knob.
Press MENU.
2.1 Wireless transmission
See chapter 5.3.
2.2
GPS settings
Using buttons and highlight the required position. Press ENTER to select the option.
Using buttons , select GPS on or off. Press ENTER to select the option.
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MRU-200 MRU-200-GPS USER MANUAL
Note:
– Switching GPS on during the resistance (resistivity) measurement is
signalling by the icon in the left upper corner of the display. Searching GPS
signal is indicated by the blinking icon. The icon stops blinking and is
displayed continuously, when the satellite signal is found.
2.3 Measurement settings
Using buttons and highlight the required position. Press ENTER to select the
option.
2.3.1 Mains frequency
It is necessary to determine the frequency of the mains which is the source of
potential interference in order to select the appropriate frequency of the
measurement signal. Solely measurements based upon the correct frequency of
the measurement signal will guarantee the optimum interference filtering. The
meter is adapted for filtering of interference from 16 2/3 Hz, 50 Hz, 60 Hz
and 400 Hz networks. It also has the function of automatic specification of
the parameter in question (selection of the mains frequency = AUTO), which is
based upon the result of measurements of the interference voltage realized
before the earth resistance measurement. The function is active if the
interference voltage UN 1 V. Otherwise the meter adopts the last frequency
value selected from the MENU.
Using buttons and select the frequency and press ENTER to select the option.
MRU-200 MRU-200-GPS USER MANUAL
7
2.3.2 Calibration of measurement clamps
The clamp bought apart for a meter that was purchased before must be
calibrated before it is used for the first time. It may be periodically
calibrated in order to avoid the influence of the ageing elements upon the
resolution of measurements. The procedure of calibration must be realized also
after clamp has been replaced. Calibration of hard clamps
Having read the preliminary information ENTER.
Follow the displayed instructions.
Once the calibration has been successfully concluded, the following will be displayed.
The meter has determined the correction factor for connected clamp. The factor is saved in the memory also when the power supply of the meter is off until the following successful calibration of the clamp has been performed.
8
MRU-200 MRU-200-GPS USER MANUAL
Calibration of flexible clamps (using ERP-1 adapter)
After reading the introductory information press ENTER.
Follow on-screen prompts displayed by the meter and short H and E sockets with a wire.
Connect ERP-1 adapter to the terminal of the clamps. Turn ERP-1 adapter ON.
MRU-200 MRU-200-GPS USER MANUAL
9
Connect flexible clamps to ERP-1 adapter.
Wrap the clamps around the wire referred to in sec. (up to 4 times). Use FLEX
and TURNS buttons on ERP-1 adapter to select the clamps and number of wraps,
according to the actual situation around the wire referred to in sec. .
Press START button on MRU meter. If the calibration is successful, you will see the following screen.
The meter has determined the correction factor for connected clamp. The factor is saved in the memory also when the power supply of the meter is off until the following successful calibration of the clamp has been performed.
10
MRU-200 MRU-200-GPS USER MANUAL
Note:
– Make sure the test lead passes centrally through the clamp. – If hard clamps
and the ERP-1 adapter with flexible clamps are used interchangeably for
measurements, the calibration must be performed each time the hard clamps are
replaced with ERP-1. The meter does not store individual calibration
coefficients for hard clamps and the ERP-1 adapter.
Additional information displayed by the meter
Message
ERROR: CLAMP NOT CONNECTED OR NOT PUT ON WIRE CONNECTED TO H AND E SOCKET!
ERROR: WIRE NOT CONNECTED TO H AND E TERMINAL! CALIBRATION ABORTED. PRESS
ENTER ERROR: CALIBRATION COEFFICIENT OUT OF RANGE. CALIBRATION ABORTED. PRESS
ENTER
Cause The clamp is not connected
No wire
Incorrect calibration factor
Procedure Check whether the clamp is connected to the device or whether it is
placed upon the test lead used by the meter to force the passage of current.
Revise the connections
Check the quality of the connections and/or replace the clamp.
2.3.3 Earth resistivity settings
Using buttons , ,
and select the result and the distance unit and press ENTER to confirm.
MRU-200 MRU-200-GPS USER MANUAL
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2.4 Meter settings
Use , to select an option. Press ENTER to confirm.
2.4.1 LCD contrast
Using the buttons and
2.4.2 LCD Backlight
set the contrast value and press ENTER.
Use , to set the time for LCD backlight shut-off and press ENTER to confirm.
2.4.3 AUTO-OFF settings
The setting determines the time before the automatic turning-off of the device
when it is not in use. Use buttons and to set the time or AUTO-OFF disable,
press ENTER.
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MRU-200 MRU-200-GPS USER MANUAL
2.4.4 Display settings
The setting permits to turn on/off the setting bar display. Use buttons and to
set the display of the setting bar (measurement parameters), press ENTER.
Visible bar
2.4.5 Date and time
Hidden bar
2.4.6 Battery discharging
The procedure is fully described in chapter 6.5.
Use buttons and to select the value to be modified (Day, month, hour, minute).
Use buttons and to set the value. Once the date and time have been set, press
ENTER.
MRU-200 MRU-200-GPS USER MANUAL
13
2.4.7 Programme update
NOTE! Before you proceed to programming, charge the accumulators. During
programming do not turn the meter off or disconnect the transmission cable.
Before you proceed to updating the programme, download from the manufacturer’s
web page the meter programming software, install it in the computer and
connect the meter to the computer.
Having chosen the Program update in the MENU, proceed in accordance with the
instructions displayed by the programme.
2.5 Language choice
Use buttons and to select Language choice in the main MENU and press
ENTER. Use buttons and to select the language and press ENTER.
2.6 Information on the manufacturer
Use buttons and in order to select Product info and press ENTER.
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MRU-200 MRU-200-GPS USER MANUAL
Note:
Measurements
During measurements the status bar is displayed.
3.1 Measurement of resistance of earth connection and equipotential bonding (2P)
Note: The measurement complies with the requirements specified in the norm EN 61557-4 (U<24 V, I>200 mA for R10 ).
Turn the meter on. Set the rotational function selector at 2P.
Connect the object being measured to the terminals S and E of the meter.
The meter is ready for measurement. The auxiliary display shows the value of the interference voltage and its frequency. The setting bat shows the mains frequency set in the MENU.
MRU-200 MRU-200-GPS USER MANUAL
15
Press START In order for the test to commence.
Read out the result.
The right side of the display shows the date, time and GPS coordinates.
The result is displayed for 20 s. It may be displayed again when ENTER is pressed.
Additional information displayed by the meter
R>19,99k UN>40V! and a continuous sonic signal
UN>24V!
NOISE!
Measurement range exceeded.
The voltage on the measurement points exceeds 40 V, the measurement is
blocked.
The voltage on the measurement points exceeds 24 V but lower than 40 V, the
measurement is blocked. The value of the interfering signal is too high, the
result may be distorted by additional uncertainty.
16
MRU-200 MRU-200-GPS USER MANUAL
3.2 Calibration of the test leads
In order to eliminate the influence of the resistance of the test leads over
the result of the measurement, it is possible to realize its compensation
(auto-zeroing). In order to do so the measurement function 2P includes the
AUTOZERO subfunction.
3.2.1 Auto-zeroing on
Turn the meter on. Set the rotational function selector at 2P.
Press F1.
CAT IV 300V
Follow the displayed instructions.
E
S
Once the auto-reset function has concluded the following will be displayed:
Auto-zeroing is signalled by the legend AUTOZERO on the right-hand side of the display.
MRU-200 MRU-200-GPS USER MANUAL
17
3.2.2 Auto-zeroing off
Turn the meter on. Set the rotational function selector at 2P.
Press F1. Separate the test leads. Press START.
C AT IV 300V
E
S
Once the auto-zeroing function has been turned off, the legend AUTOZERO will
be no longer displayed.
Note:
– It is sufficient to realize compensation once for the given test leads. It
is also remembered once the meter has been turned off, until the next
successful auto-reset procedure.
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MRU-200 MRU-200-GPS USER MANUAL
3.3 Earth resistance measurement with 3-pole method (RE3P)
The basic kind of the earth resistance measurement is 3-pole measurement.
Disconnect the tested earth electrode for the object installation.
Turn the meter on. Set the rotational function selector at 3P.
CAT IV 300V
E
SH
Connect the current electrode driver into ground to the H socket of the meter.
Connect the voltage electrode driver into ground to the S socket of the meter.
Connect the tested earth electrode to the E socket of the meter. The tested
earth electrode as well as the current electrode and voltage electrode should
be aligned.
The meter is ready for measurement. The auxiliary display shows the value of
the interference voltage and its frequency. The setting bar shows the mains
frequency set in the MENU.
MRU-200 MRU-200-GPS USER MANUAL
19
Press F1 to order to modify the measuring voltage.
Use buttons and to set the measuring voltage and press ENTER.
Press START In order for the test to commence measurement.
Read out the result. Current electrode resistance Voltage electrode resistance
Additional uncertainty caused by the resistance of the electrodes Displayed,
when >30%
By pressing the F4 button you can display GPS coordinates. The result is
displayed for 20 s. It may be displayed again when ENTER is pressed.
20
MRU-200 MRU-200-GPS USER MANUAL
S
Note:
Repeat the measurements (see points 3, 7 and 8) moving the voltage electrode by a couple of meters: approaching it to and moving it away from the tested earth electrode. If the RE test results differ more than 3%, then it is necessary to increase significantly the distance between the current electrode from the earth electrode in question and repeat the measurement.
Earth resistance measurement may be realized if the interference voltage does not exceed 24 V. The interference voltage is measured up to 100 V. Do not connect the meter to a voltage exceeding 100 V.
– Pay particular attention to the quality of the connection of the tested
object with the test leads the contact area must be cleaned of paint, rust,
etc. – If the resistance of the auxiliary electrodes is too high, then the
measurement of the RE earth electrode will be distorted by additional
uncertainty. A particularly high measurement uncertainty is generated if we
measure a low value of the earth resistance with electrodes of a weak contact
with the ground (such a situation occurs often if the earth electrode is
properly made and the upper layer of the ground is dry and characterised by a
low conductivity). Then the relation between the electrode resistance and the
resistance of the measured earthing is very high, and so is the case of the
measurement uncertainty which depends on it. What may be done then is to
perform, in accordance with the formulae specified in point 10.2,
calculations, which will permit to evaluate the influence of the measurement
conditions. It is also possible to improve the contact of the electrode with
the ground, for example by means of moistening of the place when the electrode
is driven, its driving into the ground in another place or using a
80-centimetre electrode. Check also the test leads and make sure the
insulation is not damaged and the contacts: test lead banana plug
electrode are not corroded or loosened. In most cases the achieved resolution
of the measurement is sufficient, but it is necessary to be conscious of the
uncertainty the measurement is burdened with.
– If the resistance of H and S electrodes or one of them exceeds 19.9 k, an
appropriate message is displayed: “RH and RS electrodes resistance are higher
than 19.9 k! Measurement impossible!”. – Manufacturer’s calibration doesn’t
include the resistance of test leads. Displayed result is sum of measured
object and test leads resistance.
Additional information displayed by the meter
RE>19,99k UN>40V! and a continuous sonic signal
UN>24V!
LIMIT!
NOISE!
Measurement range exceeded.
The voltage on the measurement points exceeds 40 V, the measurement is
blocked.
The voltage on the measurement points exceeds 24 V but lower than 40 V, the
measurement is blocked. The uncertainty of the electrode resistance >30%.
(Uncertainties calculated on the basis of the measured values) The value of
the interfering signal is too high, the result may be distorted by additional
uncertainty.
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3.4 Earth resistance measurement with 4-wire method (RE4P)
The 4-wire method is recommended in the case of measurements of earth
resistance of very low values. It permits to eliminate the influence of the
test leads resistance over the result of the measurement. In order to evaluate
the resistance of the ground it is recommended to use the dedicated
measurement function (point 3.9).
Disconnect the tested earth electrode for the object installation.
Turn the meter on. Set the rotational function selector at 4P.
CAT IV 300V
E
ES
S
H
E ES S H
Connect the current electrode driver into ground to the H socket of the meter.
Connect the voltage electrode driver into ground to the S socket of the meter.
Connect the tested earth electrode to the E socket of the meter. Connect the
ES socket to the earth electrode In question below the E cable. The tested
earth electrode as well as the current electrode and voltage electrode should
be aligned.
The meter is ready for measurement. The auxiliary display shows the value of
the interference voltage and its frequency. The setting bar shows the mains
frequency set in the MENU.
22
MRU-200 MRU-200-GPS USER MANUAL
Press F1 to order to modify the measuring voltage.
Use buttons and to set the measuring voltage and press ENTER.
Press START In order for the test to commence measurement.
Read out the result. Current electrode resistance Voltage electrode resistance
Additional uncertainty caused by the resistance of the electrodes
By pressing the F4 button you can display GPS coordinates.
The result is displayed for 20 s. It may be displayed again when ENTER is
pressed.
MRU-200 MRU-200-GPS USER MANUAL
23
S
Note:
Repeat the measurements (see points 3, 7 and 8) moving the voltage electrode by a couple of meters: approaching it to and moving it away from the tested earth electrode. If the RE test results differ more than 3%, then it is necessary to increase significantly the distance between the current electrode from the earth electrode in question and repeat the measurement.
Earth resistance measurement may be realized if the interference voltage does not exceed 24 V. The interference voltage is measured up to 100 V. Do not connect the meter to a voltage exceeding 100 V.
– Pay particular attention to the quality of the connection of the tested
object with the test leads the contact area must be cleaned of paint, rust,
etc. – If the resistance of the auxiliary electrodes is too high, then the
measurement of the RE earth electrode will be distorted by additional
uncertainty. A particularly high measurement uncertainty is generated if we
measure a low value of the earth resistance with electrodes of a weak contact
with the ground (such a situation occurs often if the earth electrode is
properly made and the upper layer of the ground is dry and characterised by a
low conductivity). Then the relation between the electrode resistance and the
resistance of the measured earthing is very high, and so is the case of the
measurement uncertainty which depends on it. What may be done then is to
perform, in accordance with the formulae specified in point 10.2,
calculations, which will permit to evaluate the influence of the measurement
conditions. It is also possible to improve the contact of the electrode with
the ground, for example by means of moistening of the place when the electrode
is driven, its driving into the ground in another place or using a
80-centimetre electrode. Check also the test leads and make sure the
insulation is not damaged and the contacts: test lead banana plug
electrode are not corroded or loosened. In most cases the achieved resolution
of the measurement is sufficient, but it is necessary to be conscious of the
uncertainty the measurement is burdened with.
– If the resistance of H and S electrodes or one of them exceeds 19.9 k, an
appropriate message is displayed: “RH and RS electrodes resistance are higher
than 19.9 k! Measurement impossible!”. – Manufacturer’s calibration doesn’t
include the resistance of test leads. Displayed result is sum of measured
object and test leads resistance.
Additional information displayed by the meter
RE>19,99k UN>40V! and a continuous sonic signal
UN>24V!
LIMIT!
NOISE!
Measurement range exceeded.
The voltage on the measurement points exceeds 40 V, the measurement is
blocked.
The voltage on the measurement points exceeds 24 V but lower than 40 V, the
measurement is blocked. The uncertainty of the electrode resistance > 30%.
(Uncertainties calculated on the basis of the measured values) The value of
the interfering signal is too high, the result may be distorted by additional
uncertainty.
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MRU-200 MRU-200-GPS USER MANUAL
CAT IV 300V
3.5 Earth resistance measurement with 3-pole method with additional clamp
(RE3P+C)
Turn the meter on. Set the rotational function selector at 3P .
E SH
Connect the current electrode driver into ground to the H socket of the meter.
Connect the voltage electrode driver into ground to the S socket of the meter.
Connect the tested earth electrode to the E socket of the meter. The tested
earth electrode as well as the current electrode and voltage electrode should
be aligned. Snap the clamp on the tested earth electrode below the E cable
connection.
The meter is ready for measurement. The auxiliary display shows the value of
the interference voltage and its frequency. The setting bar shows the mains
frequency set in the MENU.
Press button F2 to select measurement with C-3 clamp.
MRU-200 MRU-200-GPS USER MANUAL
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Use buttons and to select C-3 clamp and press ENTER.
Press F1 to ordered to modify the measuring voltage.
Use buttons and to set the measuring voltage and press ENTER.
Press START in order for the test to commence measurement.
Read out the result.
Current electrode resistance Voltage electrode resistance Additional
uncertainty caused by the resistance of the electrodes.
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MRU-200 MRU-200-GPS USER MANUAL
By pressing the F4 button you can display GPS coordinates.
The result is displayed for 20 s. It may be displayed again when ENTER is pressed.
Repeat the measurements (see points 2 and 5) moving the
voltage electrode by a couple of meters: approaching it to and
moving it away from the tested earth electrode.
S
If the RE test results differ more than 3%, then it is necessary
to increase significantly the distance between the current elec-
trode from the earth electrode in question and repeat the gaug-
ing.
Notes:
Flexible clamp must not be used for this measurement.
Earth resistance measurement may be realized if the interference voltage does not exceed 24 V. The interference voltage is measured up to 100 V. Do not connect the meter to a voltage exceeding 100 V.
– The clamps are not the part of meter basic accessories, you have to purchase them apart. – The clamp must be calibrated before it is used for the first time. It may be periodically calibrated in order to avoid the influence of the ageing elements upon the resolution of measurements. The clamp calibration option is in the MENU. – Pay particular attention to the quality of the connection of the tested object with the test leads the contact area must be cleaned of paint, rust, etc. – If the resistance of the auxiliary electrodes is too high, then the measurement of the RE earth electrode will be distorted by additional uncertainty. A particularly high measurement uncertainty is generated if we measure a low value of the earth resistance with electrodes of a weak contact with the ground (such a situation occurs often if the earth electrode is properly made and the upper layer of the ground is dry and characterised by a low conductivity). Then the relation between the electrode resistance and the resistance of the measured earthing is very high, and so is the case of the measurement uncertainty which depends on it. What may be done then is to perform, in accordance with the formulae specified in point 10.2, calculations, which will permit to evaluate the influence of the measurement conditions. It is also possible to improve the contact of the electrode with the ground, for example by means of moistening of the place when the electrode is driven, its driving into the ground in another place or using a 80-centimetre electrode. Check also the test leads and make sure
MRU-200 MRU-200-GPS USER MANUAL
27
the insulation is not damaged and the contacts: test lead banana plug
electrode are not corroded or loosened. In most cases the achieved resolution
of the measurement is sufficient, but it is neces-
sary to be conscious of the uncertainty the measurement is burdened with.
– If the resistance of H and S electrodes or one of them exceeds 19.9 k, an
appropriate message is displayed: “RH and RS electrodes resistance are higher
than 19.9 k! Measurement impossible!”.
– Manufacturer’s calibration doesn’t include the resistance of test leads.
Displayed result is sum of measured object and test leads resistance.
Additional information displayed by the meter
RE>1999 UN>40V! and a continuous sonic signal
UN>24V!
NOISE!
LIMIT!
IL>max
Measurement range exceeded.
The voltage on the measurement points exceeds 40 V, the measurement is
blocked.
The voltage on the measurement points exceeds 24 V but lower than 40 V, the
measurement is blocked. The value of the interfering signal is too high, the
result may be distorted by additional uncertainty. The uncertainty of the
electrode resistance > 30%. (Uncertainties calculated on the basis of the
measured values) Excessive interfering current, the measurement error may
exceed the basic error
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MRU-200 MRU-200-GPS USER MANUAL
3.6 Earth resistance measurement with 3-pole method with ERP-1 adapter
(RE3P+ERP-1)
Turn the meter on. Set the rotational function selector at 3P .
The current electrode (driven into earth) should be connected to H socket of
the meter. The voltage electrode (driven into earth) should be connected to S
socket of the meter. The tested leg of the pole should be connected to E
socket of the meter with the lead. The tested leg of the pole, the current
electrode and the voltage electrode should be arranged in one line. Clamps
should be attached to the tested leg of the pole below the connection point of
E lead.
Select voltage measurement as described in par. 3.5.
Press F2 button to select the measurement in ERP-1.
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Use , buttons to select the measurement with ERP-1, press ENTER.
Press F3 button to select the number of pole legs.
Use , buttons to select the number of pole legs, press ENTER.
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MRU-200 MRU-200-GPS USER MANUAL
Press START. Follow the command on the screen and fix the clamps to the first leg (if not already done).
To start the measurement, press START push-button again.
After the measurement of the first leg of the pole, the measured resistance value of the tested leg is shown on the main screen as R1 for 5 seconds. After this time, the meter transfer R1 result to the window on the right side and displays a message to the user to connect the clamps to another leg of the pole.
This result may be restored on the main screen for another 5 seconds by pressing ENTER.
MRU-200 MRU-200-GPS USER MANUAL
31
After performing the measurement on the last leg of the pole and displaying
for 5 seconds the resistance result “Rn”, the device displays the resultant
earth resistance RE.
Use buttons and to change results displayed in the window on the right side of
the screen.
By pressing the F4 button you can display GPS coordinates.
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MRU-200 MRU-200-GPS USER MANUAL
3.7 Earth resistance measurement with two-clamp method (2C)
Two-clamp measurements are applied where there is no possibility of using
ground-driven electrodes.
NOTE! The two-clamp method may be used solely in the case of multiple earthing
measurements.
Turn the meter on. Set the rotational function selector at .
CAT IV 300V
C -3
E
H
N -1
Connect the transmission clam to sockets H and E, while the measurements clamp should be connected to the clamp socket. Snap the transmission clamp and measurement clamp on the tested earth electrode AT east 30 cm from each other.
The meter is ready for measurement. The auxiliary display shows the value of the leakage current passing through the clamp and its frequency.
Press START In order for the test to commence measurement.
MRU-200 MRU-200-GPS USER MANUAL
33
Read out the result. The right side of the display
shows the date, time and GPS coordinates.
The result is displayed for 20 s. It may be displayed again when ENTER is
pressed.
Notes:
Measurements may be performed in the presence of interference current not
exceeding 3 A RMS and whose frequency complies with the value set in the MENU.
Flexible clamp and flexible clamps connected to the ERP-1 adapter must not be used for this measurement.
– The clamps are not the part of meter basic accessories, you have to purchase them apart. – The clamp must be calibrated before it is used for the first time. It may be periodically calibrated in order to avoid the influence of the ageing elements upon the resolution of measurements. The clamp calibration option is in the MENU. – If the clamp current is insufficient, an appropriate message is displayed: “Measured current is too low. Measurement impossible!”.
Additional information displayed by the meter
RE>149,9 UN>40V! and a continuous sonic signal
UN>24V!
NOISE!
Measurement range exceeded.
The voltage on the measurement points exceeds 40 V, the measurement is
blocked.
The voltage on the measurement points exceeds 24 V but lower than 40 V, the
measurement is blocked. The value of the interfering signal is too high, the
result may be distorted by additional uncertainty.
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MRU-200 MRU-200-GPS USER MANUAL
3.8 Earth impedance measurement with impulse method (RE4P )
The impulse method is applied in the case of measurement of the dynamic
impedance of lightning arrester earthing systems. It must not be used for the
purpose of measurements of protective and working earthing systems.
Due to the high steepness of the test pulse leading edge the inductivity of
the earth electrode highly influences its impedance. Therefore the impedance
of the earth electrode measured by means of the impulse method depends upon
its length and the steepness of the test pulse leading edge.
The inductivity of the earth electrode causes a shift between the current
spikes and the resultant voltage drop. Hence extensive earth electrodes of a
low resistance measured by means of the lowfrequency method may have a much
higher value of the dynamic impedance. The impulse impedance is calculated on
the basis of the following formula:
U
ZE
S
IS
Where US, IS peak value of the current and voltage.
The impulse method is used to determine the resultant earth impedance.
Therefore the control measurement points must not be undone.
It is recommended to place the test leads in such a manner that the angle
between them is at least 60°.
Note: Measuring leads must be completely unrolled. Otherwise the result of the measure may be wrong.
The following illustration explains the numbers which determine the shape of
the pulse (in accordance with EN 62305-1 Lightning protection Section 1.
General Requirements).
90%
t
50%
10%
T1 T2
t = current amplitude T1 = pulse leading edge duration T2 = time to semi-spike
The pulse shape is determined by the relation T1/T2 eg: 4/10 s.
MRU-200 MRU-200-GPS USER MANUAL
35
C AT IV 300V
Turn the meter on. Set the rotational function selector at 4P .
E ES S H
Connect the current electrode driver into ground to the H socket of the meter.
Connect the voltage electrode driver into ground to the S socket of the meter.
Connect the tested earth electrode to the E socket and the shield of the H
cable. Connect the ES socket to the earth electrode in question below the E
cable. The tested earth electrode and the current electrode and voltage
electrode should be placed in such a manner than the angle between the gauging
aligned amount to 60°.
The meter is ready for measurement. The auxiliary display shows the value of
the interference voltage and its frequency. The setting bar shows the pulse
build up time.
Press F1 in order to modify the pulse shape.
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MRU-200 MRU-200-GPS USER MANUAL
Use buttons and to set the pulse shape and press ENTER.
Press START In order for the test to commence measurement. Read out the
result. Current electrode resistance Voltage electrode resistance Additional
uncertainty caused by the resistance of the electrodes.
By pressing the F4 button you can display GPS coordinates.
The result is displayed for 20 s. It may be displayed again when ENTER is
pressed.
MRU-200 MRU-200-GPS USER MANUAL
Notes:
Earth impedance measurement may be realized if the interference voltage does not exceed 24 V. The interference voltage is measured up to 100 V. Do not connect the meter to a voltage exceeding 100 V.
– Impulse 8/20 s is available from firmware version 2.04. – RH and RS are
measured by means of the low-frequency method. – Pay particular attention to
the quality of the connection of the tested object with the test leads the
contact area must be cleaned of paint, rust, etc. – If the resistance of the
auxiliary electrodes is too high, then the measurement of the ZE earth
electrode will be distorted by additional uncertainty. A particularly high
measurement uncertainty is generated if we measure a low value of the earth
resistance with electrodes of a weak contact with the ground (such a situation
occurs often if the earth electrode is properly made and the upper layer of
the ground is dry and characterised by a low conductivity). Then the relation
between the electrode resistance and the resistance of the measured earthing
is very high, and so is the case of the measurement uncertainty which depends
on it. What may be done then is to perform, in accordance with the formulae
specified in point 10.2, calculations, which will permit to evaluate the
influence of the measurement conditions. It is also possible to improve the
contact of the electrode with the ground, for example by means of moistening
of the place when the electrode is driven, its driving into the ground in
another place or using a 80-centimetre electrode. Check also the test leads
and make sure the insulation is not damaged and the contacts: test lead
banana plug electrode are not corroded or loosened. In most cases the
achieved resolution of the measurement is sufficient, but it is necessary to
be conscious of the uncertainty the measurement is burdened with.
– If the resistance of H and S electrodes or one of them exceeds 1 k, an
appropriate message is displayed: “RH and RS electrodes resistance are higher
than 1 k! Measurement impossible!”.
Additional information displayed by the meter
ZE>1991 ZE>3002 UN>40V! and a continuous sonic signal
UN>24V!
LIMIT!
NOISE!
Measurement range exceeded.
1 – MRU-200 up to serial number E31440, MRU-200-GPS up to serial number E40434
2 – MRU-200 from serial number E31441, MRU-200-GPS from serial number E40435
The voltage on the measurement points exceeds 40 V, the measurement is
blocked.
The voltage on the measurement points exceeds 24 V but lower than 40 V, the
measurement is blocked. The uncertainty of the electrode resistance > 30%.
(Uncertainties calculated on the basis of the measured values) The value of
the interfering signal is too high, the result may be distorted by additional
uncertainty.
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MRU-200 MRU-200-GPS USER MANUAL
3.9 Current measurement (I)
The present function facilitates measurements of the current effective value
using measurement clamp. It may be used for example for the purpose of
measurements of the leakage current in the installation in question. It is
possible to choose between several types of clamps, which differ in regard to
diameter and measured current range (see Technical Data).
Turn the meter on. Set the rotational function selector at I.
Press F1 to select type of clamp.
Use buttons and to select the type of clamp and press ENTER.
Notes:
– Measurements are continuous and there is no possibility of their being
saved. – Flexible clamp F series may be used solely for the purpose of
measurements of currents > 1 A.
MRU-200 MRU-200-GPS USER MANUAL
39
3.10 Earth resistivity measurement ()
For the purpose of earth resistivity measurements which are used as a
preliminary measure for the project of earthing systems or in geology there
is a separate function, which is selected by means of the rotational function
selector: earth resistivity measurements . The function is metrologically
identical as the 4-wire earth resistance measurement, but it includes an
additional procedure of storing of the distance between the electrodes. The
result of the measurement is the resistance value which is calculated
automatically in accordance with the following formula: = 2LRE, which is used
in the Wenner’s measurement method. The method in question assumes equal
distances between electrodes.
Turn the meter on. Set the rotational function selector at .
E ES S H
L
L
L
Connect the four aligned and equally spacer electrodes, which are driven into the ground, to the meter, and do so In accordance with the diagram above
The meter is ready for measurement. The auxiliary display shows the value of the interference voltage and its frequency. The setting bar shows the measurement voltage, mains frequency set in the MENU and the distance between the electrodes.
Press F1 to change the measurement voltage.
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MRU-200 MRU-200-GPS USER MANUAL
Use buttons and to set the measuring voltage and press ENTER.
Press START to commerce measurement. The meter will activate the mode of
selection of the distance between electrodes.
Use buttons and to set the distance between electrodes and press ENTER In
order to commerce measurement.
Read out the result. Current electrode resistance Voltage electrode resistance
Additional uncertainty caused by the resistance of the electrodes
By pressing the F4 button you can display GPS coordinates.
The result is displayed for 20 s. It may be displayed again when ENTER is pressed.
MRU-200 MRU-200-GPS USER MANUAL
41
Notes:
Earth resistance measurement may be realized if the interference voltage does not exceed 24 V. The interference voltage is measured up to 100 V. Do not connect the meter to a voltage exceeding 100 V.
– Calculations are based upon the assumption that the distances between the
specific measurement electrodes are equal (the Wenner’s method). If this is
not the case the earthing resistance measurement must be realized by means of
the four-pole method and calculations must be performed individually. – Pay
particular attention to the quality of the connection of the tested object
with the test leads the contact area must be cleaned of paint, rust, etc. –
If the resistance of the auxiliary electrodes is too high, then the
measurement of the RE earth electrode will be distorted by additional
uncertainty. A particularly high measurement uncertainty is generated if we
measure a low value of the earth resistance with electrodes of a weak contact
with the ground (such a situation occurs often if the earth electrode is
properly made and the upper layer of the ground is dry and characterised by a
low conductivity). Then the relation between the electrode resistance and the
resistance of the measured earthing is very high, and so is the case of the
measurement uncertainty which depends on it. What may be done then is to
perform, in accordance with the formulae specified in point 10.2,
calculations, which will permit to evaluate the influence of the measurement
conditions. It is also possible to improve the contact of the electrode with
the ground, for example by means of moistening of the place when the electrode
is driven, its driving into the ground in another place or using a
80-centimetre electrode. Check also the test leads and make sure the
insulation is not damaged and the contacts: test lead banana plug
electrode are not corroded or loosened. In most cases the achieved resolution
of the measurement is sufficient, but it is necessary to be conscious of the
uncertainty the measurement is burdened with.
– If the resistance of H and S electrodes or one of them exceeds 19.9 k, an
appropriate message is displayed: “RH and RS electrodes resistance are higher
than 19.9 k! Measurement impossible!”.
Additional information displayed by the meter
999km UN>40V! and a continuous sonic signal
UN>24V!
LIMIT!
NOISE!
Measurement range exceeded.
The voltage on the measurement points exceeds 40 V, the measurement is
blocked.
The voltage on the measurement points exceeds 24 V but lower than 40 V, the
measurement is blocked. The uncertainty of the electrode resistance > 30%.
(Uncertainties calculated on the basis of the measured values) The value of
the interfering signal is too high, the result may be distorted by additional
uncertainty.
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MRU-200 MRU-200-GPS USER MANUAL
4 Memory
The MRU-200 / MRU-200-GPS meters are equipped with a memory whose capacity is
990 results of resistance measurements. Individual measurements are saved in
memory cells. The whole memory is divided into 10 banks with 99 cells each.
Each result may be saved in a cell of a defined number and in the selected
bank, so the user of the meter may, at their own discretion assign numbers of
the cells to individual measurement points and the numbers of the banks to
individual objects, realize measurements in any order and repeat them without
loosing other data.
The memory of the results of the measurements is not deleted when the meter is
turned on, so they may be read further on or transmitted to the computer. The
number of the current cell and the bank is not modified either.
It is recommended to delete the memory once the data have been read or before
a new series of measurements is realized. New measurements may be saved in the
same cells as the previous ones.
4.1 Saving of the measurement results in the memory
Once the measurement has finished press ENTER.
Empty cell
Occupied cell
Selection of the measure (cell) is realized by means of the buttons and . Bank May be selected with the buttons and . To save press ENTER.
Should you intend to save data In an occupied cell, the following message will be displayed:
Once the option has been selected with the buttons and press ENTER.
MRU-200 MRU-200-GPS USER MANUAL
43
4.2 Memory erasing Note:
– During the process of memory erasing the progress bar is being displayed.
Turn the meter on. Set the rotational function selector at MEM.
Using the buttons and “Memory erasing”.
highlight
Press ENTER.
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MRU-200 MRU-200-GPS USER MANUAL
Follow the displayed instructions.
4.3 Memory browsing
Use the buttons and to select complete “Memory erase”, “Bank erase” or “Measurement erase”
Use the buttons and “Memory browsing”.
to highlight
Press ENTER.
Use the buttons and to select bank and the buttons and to select a cell.
Note:
– During a memory search empty cells and banks are unavailable. ,,Meas. 1/20″
means the first measurement in a group of 20; cells 21…99 are empty and
unavailable. The same principle refers to banks. If the memory is not filled
in a continuous manner, then empty measurements and banks are skipped during
browsing.
MRU-200 MRU-200-GPS USER MANUAL
45
5 Data transmission
Remarks:
– Data transmission is not possible during the charging of accumulators.
5.1 Computer connection accessories
What is necessary in order to operate the meter with a computer is additional
accessories, namely a USB cable or Bluetooth module and appropriate software.
If the required accessories have not been purchased along with the meter, then
they are available from the manufacturer or an authorized distributor.
The accessories may be used in case of many devices manufactured by SONEL S.A.
which are equipped with the USB interface and/or Bluetooth module.
Detailed information regarding software is available from the manufacturer or
an authorized distributor.
5.2 Connection of the meter to a computer
1. Set the rotational function selector at MEM. 2. Connect the cable to the
USB port of the computer and the USB socket of the meter. 3. Start the SONEL
READER programme.
5.3 Data transmission with Bluetooth module
Starting from serial number E30001 the meters are equipped with BT module
instead of OR-1. Starting from serial number E40001 the meters are equipped
with BT module instead of OR-1.
1. Select Wireless transmission in the main MENU of the meter.
or set the function switch to MEM and press F1.
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MRU-200 MRU-200-GPS USER MANUAL
2. Connect Bluetooth module to the USB socket of the PC, unless it is
integrated into the PC. 3. During the process of pairing the meter with a PC
enter PIN code compatible with the PIN code of the meter defined in main
settings. 4. On the computer start data storing programme. If a PIN code
change is necessary, select Modify PIN code.
Set the required code with the cursors.
Note:
Standard pin for Bluetooth is “123”. – The data transmission may be
interrupted using the ESC button. – With the USB cable active the wireless
transmission is not possible.
MRU-200 MRU-200-GPS USER MANUAL
47
6 Power supply
Note: Instrument MRU-200 / MRU-200-GPS has been designed for use only with the
supplied rechargeable batteries. Using disposable instead of rechargeable
batteries can take place only in emergency cases (e.g. total discharge of
batteries during field measurements of electric poles). However, a rapid
discharge of disposable batteries (several measurements) and malfunction of
the instrument at high instantaneous power consumption should be expected.
6.1 Monitoring of the power supply voltage
The level of the charge of the batteries or accumulators is currently
indicated by the symbol in the right upper corner of the display:
Battery charged. Battery low. Battery fully discharged.
Battery fully discharged, Measuring blocked.
Note:
– The displayed BAT symbol means insufficient power supply voltage and the
need to charge the accumulators, – Measurements realized with an insufficient
meter power supply voltage are distorted with additional errors which are
impossible to ascertain by the user and thus they cannot constitute a basis
for a conclusion of correctness of the tested earthing system.
6.2 Replacement of accumulators
The MRU-200 / MRU-200-GPS meter is equipped with a package of NiMH
accumulators and charger. The package of accumulators is placed in a
compartment. The charger is installed inside the meter casing and it may be
used solely to charge the original accumulators. It is powered from an
external power supply. It is also possible to use a car lighter socket.
48
MRU-200 MRU-200-GPS USER MANUAL
WARNING: If the test leads are left in the sockets during replacement of the
batteries or the package of accumulators, there is a risk of electric shock
with a dangerous voltage.
In order to replace the package of accumulators it is necessary to do the
following: Remove all the test leads from the sockets and turn the meter off,
Remove the four screws of the accumulators/batteries compartment (in the lower
part of the
casing), Remove the compartment, Insert the compartment in the meter, Replace
the four screws of the accumulators/batteries compartment.
NOTE! Do not use the meter when the accumulator compartment is removed or open or power it from other sources than those mentioned in the present manual.
6.3 Fuse replacement
Remove the battery compartment to get access to two replaceable fuses: – FST
250Vac 1A, 5x20mm and – 2A 250Vac, time-delay fuse, 5x20mm.
If the instrument or battery charger does not work, before sending it for
servicing, check the fuses and, if they are blown, replace them with identical
ones. The fuses are placed in holders, near the centre of the cavity. To
remove the fuses, use a narrow tool (e.g. a screwdriver).
6.4 Charging of accumulators
Charging commences once the power supply has been connected to the meter
regardless of the fact whether the meter is on or off. During charging the
screen looks as it is presented in the following illustration. The
accumulators are charged in accordance with the algorithm of ,,quick charge”
this process permits to reduce the duration of charging to approximately four
hours. The end of the
process of charging is signalled by: Charging concluded. In order to turn the
device off, remove the power supply plug of the charger.
MRU-200 MRU-200-GPS USER MANUAL
49
Operating mode
Messages regarding the process of charging
Charging Progress, the changing interior symbolizes charging.
Note:
– As a result of interferences in the network it is possible that the process
of charging of accumulators will finish too fast. In the case too short a time
of charging is detected it is necessary to remove the plug of the charger and
start charging anew.
Additional information displayed by the meter
Message Battery connection error! No battery!
Battery temperature too low!
Precharge error
Cause Excessive voltage at the accumulator package during charging. No
communication with the accumulator controller or batteries compartment put in.
The ambient temperature is lower than 10C
A damaged or deeply discharged accumulator package
Proceeding
Check the contacts of the accumulator package. Should the problem persist,
replace the package. Check the contacts of the accumulator package. Should the
problem persist, replace the package. Put the accumulators compartment instead
of batteries. It is not possible to charge the accumulators correctly in such
a temperature. Place the meter in a warm place and commence the charging mode
anew. The present message may be displayed also in the case of deep
discharging of the accumulators. It is then recommended to try to turn the
charger on and off repeatedly. The message is displayd for a while and then
the precharge process begins again. If after several attempts the message:
Battery temperature too high! is displayed, replace the package.
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MRU-200 MRU-200-GPS USER MANUAL
6.5 Discharging of accumulators
In order to guarantee proper functioning of the accumulators (charge
indications) and prolong their durability, it is recommended to charge them
from zero from time to time. Proceed as follows in order to discharge the
accumulators:
Press MENU and highlight Meter settings. Press ENTER.
Use buttons and to select Battery discharging,and press ENTER.
Read the displayed text and accept.
Discharging, which may last up to 10 hours depending on the level of the
charge of the package, is signalled with the following message: Discharging of
accumulators in progress.
6.6 General principles regarding using Ni-MH accumulators
– If you do not use the device for a prolonged period of time, then it is
recommended to remove the accumulators and store them separately. – Store the
accumulators in a dry, cool and well ventilated place and protect them from
direct sunlight. The temperature of the environment in the case of prolonged
storage should not exceed 30C. If the accumulators are stored for a long time
in a high temperature, then the occurring chemical processes may reduce their
lifetime. – Accumulators Ni-MH resist normally 500-1000 charging cycles. The
accumulators reach their maximum capacity after being formatted (2-3 charge
and discharge cycles). The most important factor which influences the lifetime
of an accumulator is the depth of discharge. The deeper the discharge of the
accumulator, the shorter its lifetime. – The memory effect is limited in the
case of Ni-MH accumulator. These accumulators may be charged at any point with
no serious consequences. However, it is recommended to discharge them
completely every few cycles. – During storage of Ni-MH accumulators they are
discharged at the rate of approximately 30% per month. Keeping accumulators at
high temperatures may accelerate this process even 100%. In order to prevent
excessive discharge of accumulators, after which it would be necessary to
format them, it is recommended to charge the accumulators from time to time
(even if not in use).
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– Modern fast chargers detect both too low and too high a temperature of
accumulators and react to the situation adequately. Too low a temperature
should prevent the start of the process of charging, which might damage the
accumulator irreparably. An increase of the temperature of the accumulator is
a signal to stop charging and is a typical phenomenon. However charging at a
high temperature of the environment apart from reducing the lifetime causes an
accelerated increase of the temperature of the accumulator, which will be not
charged to its full capacity. – Remember that in the case of quick charging
accumulators are charged to approximately 80% of their capacity; better
results may be obtained if the process of charging is continued: the charger
goes then to the phase of charging with a low current and after next couple of
hours the accumulators are charged to their full capacity. – Do not charge or
use accumulators in extreme temperatures. Extreme temperatures reduce the
lifetime of batteries and accumulators. Avoid placing devices powered from
accumulators in very hot environments. The nominal working temperature must be
absolutely observed.
7 Cleaning and maintenance
NOTE! Apply solely the maintenance methods specified by the manufacturer
within the present manual.
The casing of the meter may be cleaned with a soft, damp cloth using all-
purpose detergents. Do not use any solvents or cleaning agents which might
scratch the casing (powders, pastes, etc.).
Clean the auxiliary electrode with water and dry it. Before the electrode is
stored for a prolonged period of time it is recommended to grease it with any
machine lubricant.
The reels and test leads should be cleaned with water and detergents, and then
dried.
The electronic system of the meter does not require maintenance.
8 Storage
In the case of storage of the device, the following recommendations must be
observed: Disconnect all the test leads from the meter. Clean the meter and
all its accessories thoroughly. Wind the long test leads onto the reels. In
the case the meter is to be stored for a prolonged period of time, the
batteries must be re-
moved from the device. In order to prevent a total discharge of the
accumulators in the case of a prolonged storage,
charge them from time to time.
9 Dismantling and disposal
Worn-out electric and electronic equipment should be gathered selectively,
i.e. it must not be placed with waste of another kind.
Worn-out electronic equipment should be sent to a collection point in
accordance with the law of worn-out electric and electronic equipment.
Before the equipment is sent to a collection point, do not dismantle any
elements. Observe the local regulations concerning disposal of packages, worn-
out batteries and accumulators.
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MRU-200 MRU-200-GPS USER MANUAL
10 Technical data
The specified accuracy applies to meter terminals. The abbreviation ,,m.v.” in the accuracy definition means the measured value.
10.1 Basic data
Interference voltage measurement UN (RMS)
Range
Resolution
Accuracy
0…100 V
1 V
±(2% m.v. + 3 digits)
measurement for fN 15…450 Hz frequency of measurements minimum two measurements/s
Interference frequency measurement fN
Range
Resolution
Accuracy
15…450 Hz
1 Hz
±(1% m.v. + 2 digits)
measurement for interference voltage >1 V (for interference voltage <1 V the following is displayed: f=—)
Measurement of resistance of protective conductors and equipotential bonding (2P) The measurement method: in accordance with IEC 61557-5
Range of measurement in accordance with IEC 61557-4: 0,045 … 19,99 k
Range
Resolution
Accuracy
0,000…3,999 *
0,001
±(2% m.v. + 4 digits)
4,00…39,99
0,01
40,0…399,9
0,1
±(2% m.v. + 2 digits)
400…399 9
1
4,00…19,99 k
0,01 k
- In 0,000…0,045 range uncertainty is unspecified.
±(5% m.v. + 2 digits)
Measurement of earth resistance 3-pole method (RE3P), 4-wire method (RE4P)
The measurement method: 3-pole, in accordance with IEC 61557-5
Range of measurement in accordance with IEC 61557-5: 0,100 … 19,99 k
Range
Resolution
Accuracy
0,000…3,999 *
0,001
±(2% m.v. + 4 digits)
4,00…39,99
0,01
40,0…399,9
0,1
±(2% m.v. + 2 digits)
400…3999
1
4,00…19,99 k
0,01 k
±(5% m.v. + 2 digits)
- For 3-pole method in 0,000…0,045 range uncertainty is unspecified.
Measurement of resistance of auxiliary electrodes RH and RS
Range
Resolution
Accuracy
0…999
1
1,00…9,99 k
0,01 k
±(5% (RE+RH+RS) + 8 digits)
10,0…19,9 k
0,1 k
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53
Measurement of earth resistance 3-pole method with additional clamp (RE3P+C)
Range of measurement in accordance with IEC 61557-5: 0,120 … 1999
Range
Resolution
Accuracy
0,000…3,999 * 4,00…39,99
0,001 0,01
±(8% m.v. + 4 digits)
40,0…399,9
0,1
±(8% m.v. + 3 digits)
400…1999
1
- In 0,000…0,045 range uncertainty is unspecified.
Measurement of multiple earth resistance two-clamp method (2C)
Range
Resolution
Accuracy
0,00…19,99
0,01
±(10% m.v. + 3 digits)
20,0…149,9
0,1
±(20% m.v. + 3 digits)
Earth resistivity measurement ()
The measurement method: Wenner’s, = 2LRE
Range
Resolution
0,0…199,9 m
0,1 m
200…1999 m
1 m
2,00…19,99 km
0,01 km
20,0…99,9 km
0,1 km
100…999 km
1 km
distance between measurement probes (L): 1…50 m
Accuracy
Depends on the accuracy of the RE 4P measurement but not less than ±1 digit.
Earth impedance measurement impulse method (RE4P )
Range
Resolution
Accuracy
0,0…99,9 100…199
0,1 1
±(2,5% m.v. + 3 digits)
200…300 1
1 1
±(5% m.v. + 3 digits)1
1 – MRU-200 from serial number E31441, MRU-200-GPS from serial number E40435
impulse shape: 4/10 µs, 8/20 s or 10/350 µs
impulse measurement current: approximately 1 A
spike voltage: approximately 1500 V
Measurement of leakage damage current (RMS)
Range
Resolution
0,1…99,9 mA 1
0,1 mA
100…999 mA 1
1 mA
1,00…4,99 A 1,2,3,4
0,01 A
5,00…9,99 A1,2,3,4
10,0…99,9 A1,2,3,4
100 … 300 A1,2,3,4
1 clamp (diameter 52 mm) C-3 2 flexible clamp F series 3 flexible
clamp FS-2 4 flexible clamp FSX-3 frequency range: 45…400 Hz
0,01 A 0,1 A 1 A
Accuracy ±(8% m.v. + 5 digits) ±(8% m.v. + 3 digits) ±(5% m.v. + 5 digits)
1,3,4
unspecified 2 unspecified for 0…2 A 3 unspecified for 0…1 A 4
±(5% m.v. + 5 digits)
54
MRU-200 MRU-200-GPS USER MANUAL
10.2 Other technical data
a) type of insulation acc. to EN 61010-1 and IEC 61557…………………………………………………. double
b) measurement category acc. to EN 61010-1 (for 2000 m a.s.l.) ………………………………….. IV 300 V
c) protection grade of the casing in accordance with EN 60529……………………………………………IP54
d) maximum interference voltage AC + DC at which a measurement may be performed………….24 V
e) maximum measured interference voltage ……………………………………………………………………100 V
f) maximum interference current at which a measurement of the earth resistance by means of the
clamp method is performed ………………………………………………………………………………….3 A RMS
g) frequency of the measurement current ………………. 125 Hz for 16 2/3 Hz, 50 Hz, 400 Hz networks
………………………………………………………………………………………………. 150 Hz for 60 Hz networks
h) measurement voltage and current for 2P……………………..U < 24 V RMS, I 200 mA for
R 60 i) measurement voltage for RE3P, RE4P ……………………………………………………………… 25 V or 50
V j) measurement current (short-circuit current) for RE3P,
RE4P………………………………………>200 mA
k) maximum resistance of auxiliary electrodes ………………………………………………………………. 20 k
l) signalling of insufficient clamp current for ………………………………………………………………..0,5 mA m) power supply of the meter ……………………. accumulator package type SONEL NiMH 4,8 V 4,2 Ah
n) parameters of AC adapter for the battery charge ………………………… 100 V…240 V, 50 Hz…60 Hz
o) number of measurements for 2P ………………………………………….>1500 (1, 2 measurement/min)
p) number of measurements for RE3P, RE4P……>1200 (RE=10 , RH=RS=100 , 2 measurement/min) q) duration of a resistance measurement by means of the two- pole method …………………………. <6 s
r) duration of a resistance and resistivity measurement by means of other methods ……………… <8 s
s)
position Accuracy (in good weather conditions and visibility of satellites)……….3 m (50%CEP)
t) dimensions …………………………………………………………………………………………. 288 x 223 x 75 mm
u) mass of the meter with accumulators …………………………………………………………………….. ca. 2 kg
v) working temperature ………………………………………………………………………………………..-10…+50ºC w) operating temperature range for battery charger……………………………………………. +10ºC to +35ºC x) temperatures at which loading is interrupted…………………………………………………< 5ºC and 50ºC y) reference temperature …………………………………………………………………………………………. 23 ±2ºC z) storage temperature ………………………………………………………………………………………..-20…+80ºC aa) relative humidity ……………………………………………………………………………………………….. 20…90% bb) relative humidity nominal ……………………………………………………………………………………. 40…60% cc) altitude (above sea level)…………………………………………………………………………………….2000 m* dd) quality standard ……………………………………… design and production in accordance with ISO 9001
ee) the product meets EMC requirements according to the following standards ……………………………..
………………………………………………………………………………………… EN 61326-1 and EN 61326-2-2
NOTE * Information about the use of meter at altitude from 2000 m to 5000 m
As for voltage inputs E, ES, S, H the instrument is to be considered
downgraded to measurement category CAT III 300 V to ground (max 300 V between
inputs) or CAT IV 150 V to ground (max 150 V between inputs). Markings and
symbols indicated on the instrument are to be considered valid when using it
at altitude lower than 2000 m.
EN 55022 Compliance statement MRU-200 / MRU-200-GPS is a class A product. In a domestic environment this product may cause radio interference in which case the user may be required to take adequate measures.
MRU-200 MRU-200-GPS USER MANUAL
55
10.3 Additional data
Data regarding additional uncertainties are useful mainly in the case the
meter is used under non-standard conditions as well as for measurement
laboratories for the purpose of calibration.
10.3.1 Influence of the serial interference voltage UZ upon earth resistance
measurements for functions RE3P, RE4P, RE3P+C
R 0,000…3,999
3,999
Additional uncertainty []
(25 104
R E
2 104
Uz R
) Uz
E
(5 104 RE 2 102 ) U z
10.3.2
Influence of the serial interference voltage UZ upon earth resistance measurements for earth resistivity function ()
add [] = 2,5 (103 RE 106 RH U Z ) U Z ,
where
RE
2 L
10.3.3 Influence of the auxiliary electrodes upon earth resistance meas-
urements for function RE3P, RE4P, RE3P+C
RE
RH,RS
Additional uncertainty [%]
RH 500 and RS 500
within the range of the accuracy
0,000… …3,999
RH > 500 or RS > 500 or RH and RS > 500
(
R S
R S 106
200
R E
RH R
H
2
200
5 103
(1
1 R
E
)
RH
4
104 )
RH 1 k and RS 1 k
within the range of the accuracy
3,999
RH > 1 k or RS > 1 k or RH and RS > 1 k
(
RS
R S 106
200
RE
RH RH
2
200
5103
R H
4 104 )
RE[], RS[] and RH[] are values which are displayed by the device.
For measurements with the use of ERP-1 adapter
RE
RH,RS
Additional uncertainty for U = 25 V [%]
RH 500 and RS 500
within the range of the accuracy
0,000 …3.999
RH > 500 or RS > 500 or RH and RS > 500
( RS
R S
106
200
RE
R2 H
RH
200
5 103
(1
1 RE
)
RH
4 104 )
RH 1 k and RS 1 k
within the range of the accuracy
3.999
RH > 1 k or RS > 1 k or RH and RS >1 k
( RS
R S
106
200
RE
R2 H
5 103
RH 200
RH
20 104 )
56
MRU-200 MRU-200-GPS USER MANUAL
RE
RH,RS
Additional uncertainty for U = 50 V [%]
RH 500 and RS 500
within the range of the accuracy
0,000 …3.999
RH > 500 or RS > 500 or RH and RS > 500
( R
S
R S 106
200
R E
RH 2
R H
200
5 103
(1
1 R
E
)
RH
4 104 )
RH 1 k and RS 1 k
within the range of the accuracy
3.999
RH > 1 k or RS > 1 k or RH and RS > 1 k
( RS
R S
106
200
R E
RH 2
R H
5 103 200
R H
15 104 )
RE[], RS[] and RH[] are values which are displayed by the device.
10.3.4
Influence of the auxiliary electrodes upon earth resistance measurements for earth resistivity function ()
Uncertainty [%]
( RH RS 30000 3,2 107 4 104
RE
R H
2
R S
2
)
RE[], RS[] and RH[] are values which are displayed by the device.
10.3.5 Influence of the auxiliary electrodes upon earth resistance
measurements by means of the impulse method (RE4P )
RH
ZE
Uncertainty [%]
RH 150 0.0…199
within the range of the accuracy
RH > 150
0.0. …4.9
5.0…199 1 5.0…300 2
( RH 100 4102 ) ZE
((RH 100) 7 103)
1 – MRU-200 up to serial number E31440, MRU-200-GPS up to serial number E40434
2 – MRU-200 from serial number E31441, MRU-200-GPS from serial number E40435
ZE[] and RH[] are values which are displayed by the device.
10.3.6 Influence of the interference current IZ upon the result of the earth
resistance measurement for method RE3P+C
The MRU-200 / MRU-200-GPS meter may perform a measurement, if the value of the
interference current does not exceed 3 A RMS and the frequency complies with
the value set in the MENU.
RE
Uwy
Uncertainty []
50
25 V 50 V
(5 103
RE
I2 zakl
)
(2,5 103
RE
I
2 zakl
)
50
25 V 50 V
(70
106
R2 E
I
2 zakl
)
(50
106
RE
2
I
2 zakl
)
If the interference current exceeds 3 A the possibility of measurement is blocked.
MRU-200 MRU-200-GPS USER MANUAL
57
10.3.7 Influence of interference current on the result of the earth resistance
measurement for two-clamp method (2C)
The MRU-200 / MRU-200-GPS meter may perform a measurement, if the value of the
interference current does not exceed 3 A RMS and the frequency complies with
the value set in the MENU.
RE
Uncertainty []
0.00…4.99
within the range of the accuracy
5.00…19.9
(5
103
RE
2
I
3 zakl
)
20.0…149.9
(6
102
R E
2
I
3 zakl
)
If the interference current exceeds 3 A the possibility of measurement is blocked.
10.3.8
Influence of the relation of the resistance measured with clamp for
the multiple earthing branch to the resultant resistance (RE3P+C)
RC 99.9
Uncertainty []
(3
10
3
R C
Rw2
)
99.9
(6
10 2
R C
Rw 2
)
RC[] is the value of the resistance measured with clamps for the branch displayed by the device, and RW[] is the value of the resultant multiple earth resistance.
10.3.9 Additional uncertainties in accordance with IEC 61557-4 (2P)
Influencing factor Location Power supply voltage
Temperature
Symbol E1 E2
E3
Additional uncertainty
0%
0% (BAT not displayed)
R3,999
±0,3digits/°C
R>3,999 and <1k
±0,2digits/°C
R1k
±0,07%/°C ±0,2 digits/°C
10.3.10 Additional uncertainties in accordance with IEC 61557-5 (RE3P, RE4P, RE3P+C)
Influencing factor Location Power supply voltage
Temperature
Symbol E1 E2
E3
Serial interference voltage
E4
Resistance of electrodes and auxiliary earth electrodes
E5
Additional uncertainty
0%
0% (BAT not displayed)
R3,999
±0,3 digits/°C
R>3,999 and <1 k
±0,2 digits/°C
R1 k
±0,07%/°C ±0,2 digits/°C
In accordance with formula In 10.2.1
(Uz=3 V 50/60/400/16 2/3 Hz) In accordance with the formula in
10.2.3
58
MRU-200 MRU-200-GPS USER MANUAL
11 Positions of the meter’s cover
The movable cover enables using the meter in various positions.
1
2
3
1 Cover as the bottom of the meter 2 Cover used as a support 3 Cover in
the position that enables convenient use of the meter suspended on the neck by
means of hanging straps
12 Manufacturer
The manufacturer of the device, which also provides guarantee and post-
guarantee service is the following company:
SONEL S.A. Wokulskiego 11 58-100 widnica
Poland tel. +48 74 884 10 53 (Customer Service)
e-mail: customerservice@sonel.com web page: www.sonel.com
Attention: Service repairs must be realized solely by the manufacturer.
MRU-200 MRU-200-GPS USER MANUAL
59
NOTES
60
MRU-200 MRU-200-GPS USER MANUAL
References
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