Sonel MRU-120HD User manual

Enabling auto-zeroing
Disabling auto-zeroing
Sonel MRU-120HD
Earth Resistance Meter ●QuickStart
v1.00 | 22.05.2020
Connect the meter to the measured wire.
Run the measurement using START button.
2P
In order to eliminate the inuence of the resistance of the test leads
over the result of the measurement, its compensation (auto-zeroing)
has to be done.
Press START.
Using button F1 enable AUTOZERO mode.
Short-circuit the test leads.
Press START.
Using button F1 enable AUTOZERO mode.
Separate the test leads.
It is sufcient 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.
First steps
Turn on the meter
Select the method and connect
Congure
Obtain the result
Measurements
The meter is designed for measurements at interference voltages which do not exceed 24 V
for REmeasurements and 3 V for RCONT measurements. The voltage is measured up to 100 V,
but above 40 V is indicated as dangerous. The meter must not be connected to voltages ex-
ceeding 100 V.
UN>24V!
The voltage on the mea-
surement points exceeds
24 V but is lower than
40 V. The measurement
is blocked.
NOISE!
The value of the interfering
signal is too high. The result
may be distorted by additional
uncertainty.
LIMIT!
The uncertainty of the
electrode resistance
>30%. Uncertainties
calculated on the basis of
the measured values.
UN>40V!
and a contin-
uous
sonic signal
The voltage on the
measurement points
exceeds 40 V. The mea-
surement is blocked.
R>19,99kΩ
RE>19,99kΩ
RS>19,9kΩ
RH>19,9kΩ
ρ>999kΩm
Measurement range
exceeded. IL>max
Excessive interfering
current, the measurement
error may exceed the
basic error.
Wire continuity measurement

MRU-120HD
ERP-1
Saving a result to the memory
After the measurement press ENTER.
Select memory cell using buttons ▲▼.
Select memory bank using buttons ◄►.
Connect the meter to the leg of the measured pole.
Select method 3P . Connect the exible clamp to
ERP-1 adapter. Wrap the clamp around the object's
leg and it's earthing tape. Select measuring voltage.
Press START.
Earth resistivity measurement
Connect the meter to the measured earth.
Enter settings
▪F1 measuring voltage
Using button ENTER run the measurement.
Press START.
Using buttons ▲▼enter the distance between electrodes.
Main result
Additional
results
Earth resistance measurement RE
3P
3P
3P
4P
4P
Measurement of RE of poles using ERP-1 adapter
Target cell empty Target cell occupied
Press ENTER to save the result.
Enter settings
▪ F1 voltage/pulse shape
Using button START run the measurement.
Conguration and RE measurement
UN........voltage on the measurement points
fN..........interference frequency
IL..........interfering current
RH........resistance of current electrode
RS.........resistance of voltage electrode
δ..........additional uncertainty caused by the resistance
of the electrodes
Main result
Additional
results
Similarly, connect the next legs of the object. Having
the results of each leg measurement, you can calculate
the resultant resistance of the entire object from the
formula:
RE= 1
1+ ... + 1
R1Rn
Using FLEX button select the type of exible clamps
connected to the device.
Using TURNS button select the number of exible
clamp wraps around the pole leg.
Find more information
in the user manual
and on our website
www.sonel.com