Megger DLRO10HDX User manual

nNEW Onboard memory storage for test
results up to 200 records (HDX only)
nDownload to PowerDB
nNEW interchangeable test lead terminations
nHigh or low output power selection for
condition diagnosis
nOperates from battery or AC mains supply
nProtected to 600 V without blowing a fuse,
test lead live voltage warning light
nHeavy duty case: IP 65 lid closed,
IP54 operational
nSimple rotary switch selection of five test
modes, including auto start on connection
DLRO10HDX
10 A Digital Low Resistance Ohmmeter
DLRO10HDX
10 Amp Digital Low Resistance
DESCRIPTION
Augmenting Megger’s DLRO10 and 10X range the
DLRO10HDX combines ultimate simplicity of operation with
a rugged IP65 case designed for stable ground and bench
operation and provides memory storage.
These units are powered from either rechargeable battery
or mains power making it suitable for continuous testing in
production line/repetitive use environments.
Rotary switch controls are simple and easy to operate in all
weather conditions and with gloved hands. A large, clear,
backlit LCD display is easy to read from a distance. The
DLRO10HDX provides significantly enhanced compliance
and is capable of delivering 10 A into measurements up
to 250 mΩ and 1 A into measurements up to 2.5 Ω. The
duration of each test may be up to 60 seconds.
The DLRO10HDX is rated CAT III 300 V provided the
optional terminal cover is fitted to the instrument. Details of
which can be found in the ordering information panel of this
data sheet.
The DLRO10HDX provides five test modes each of which is
selected through a simple rotary control on the Mode selection
rotary switch. All memory functions, delete, download to
PowerDB and recalling test results are also accessible via the
Range Selection rotary switch.
A simple control panel enables easy navigation for
configuration settings.
History of ‘Ducter’ testing
For over 100 years the ‘Ducter test’ has been used to describe
a simple test for measuring very low contact resistances
and “Ducter”, which is still used as a trade mark, was the
name originally given to the low resistance ohmmeter
manufactured by Megger. The name Ducter was registered
by Megger in June 1908 and ‘Ducter’ has since become the
industry standard.
ADDITONAL FEATURES AND BENEFITS
nRugged case well suited to transportation with shoulder
strap and lead set pouch
nRemovable lid facilitates easy test lead connection
nOperational ingress protection is IP 54 (battery power
only) ensuring protection from the elements
n7Ah lead acid battery provides extended operation and
can be charged whilst operating from line power
nRotary mode switch with bidirectional (current reversal
with averaging cancels thermal EMFs), unidirectional,
automatic, continuous and inductive modes
nLarge, clear LCD display with backlight and contrast
adjustment
nAuto power off function conserves battery

2
DLRO10HDX
10 A Digital Low Resistance Ohmmeter
APPLICATIONS
The DLRO10HDX measures low resistance values in applications
ranging from railways and aircraft to resistance of components
in industry.
Any metallic joint can be measured but users must be aware
of measurement limitations depending on application. For
example, if a cable manufacturer plans to make resistive
measurements on a thin wire, a low test current should be
selected to prevent heating the wire thereby changing its
resistance.
Measurements on electric motors and generators will
be inductive and require the user to understand the
inductive mode and charging process before a correct result
is achieved.
The DLRO10HDX is well suited to measuring thick conductors,
bonds and quality of welding because of its 10 A range for
resistance values up to 250 mΩ.
Electromagnetic noise induced into the leads can interfere
with a reading. A noise symbol alerts the user and prevents
a measurement when the instrument detects noise above its
threshold.
When dissimilar metals are joined a thermocouple effect is
created. Users should select a bidirectional mode to ensure
cancellation of this effect. The instrument measures with
current flowing in both directions and averages the result.
Normal mode is initiated by pressing the ‘Test’ button after
connecting the test leads to the unit under test. Continuity
of all four connections is checked. Current is applied in both
forward and reverse direction following which measurement
is displayed.
Automatic mode is started as soon as the probes make
contact. Forward and reverse current measurements are made
and the average value is displayed. This mode is ideal when
working with handspikes. Each time the probes are removed
and reconnected to the load a new test will be performed
without the need to press the test button.
TEST modes
Automatic unidirectional mode applies current in one
direction only to speed up the measurement process.
However thermal EMF resulting from dissimilar metal bonds
can cause lower accuracy. Test starts automatically when
probes are connected.
Continuous mode allows repeated measurements to be made
on the same sample. Simply connect the test leads and press
the test button. The measurement is updated every three
seconds until the circuit is broken.
Inductive mode is selected when measuring resistance on, for
example, motors and generators. When measuring inductive
loads it is necessary to wait for the voltage to stabilise as the
inductive element is charged. Test leads are firmly connected
to the device under test and the ‘Test’ button pressed. The
instrument will pass the selected current through the sample
continuously in one direction only and take repetitive readings
that will gradually decrease to the true value as the voltage
stabilises. The operator decides when the result is stable and
presses the ‘Test’ button to terminate the test.
ELECTRICAL SPECIFICATIONS
Resistance/Current Ranges
The green resistance ranges on the keypad indicate low
output power (<0.25 W) outputs. Red ranges indicate higher
2.5 W (1 A) and 25 W (10 A) power outputs.
Resolution and Accuracy
Test current accuracy ±10%
Voltmeter input impedance >200 kΩ
Maximum lead resistance at 10 A <100 mΩ
Test current Resistance range Resolution (as displayed) Basic accuracy* Full scale voltage Max. power output
100 µA 0 - 2.5 kΩ 0.1 Ω ±0.2%
±200 mΩ 25 mV 25 μW
100 µA 0 - 250 Ω 0.01 Ω ±0.2%
±20 mΩ 25 mV 2.5 μW
1 mA 0 - 25 Ω 1 mΩ ±0.2%
±2 mΩ 25 mV 25 μW
10 mA 0 - 2.5 Ω 0.1 mΩ ±0.2%
±200 µΩ 25mV 250 μW
100 mA 0 - 250 mΩ 0.01 mΩ ±0.2%
±20 µΩ 25 mV 2.5 mW
1 A 0 - 25 mΩ 1 μΩ ±0.2%
±2 µΩ 25 mV 25 mW
10 A 0 - 2.5 mΩ 0.1 μΩ ±0.2%
±0.2 µΩ 25 mV 0.25 W
1 A ** 0 - 2.5 Ω 0.1 mΩ ±0.2%
±200 µΩ 2.5 V 2.5 W
10 A ** 0 - 250 mΩ 0.01 mΩ ±0.2%
±50 µΩ 2.5 V 25 W
* Basic accuracy stated assumes forward and reverse
measurements.
** Higher 2.5 W (1 A) and 25 W (10 A) power outputs.
Inductive mode or undirectional mode will introduce an
undefined error if an external EMF is present.
Basic accuracy at reference conditions.

3
DLRO10HDX
10 A Digital Low Resistance Ohmmeter
GENERAL SPECIFICATIONS
Temperature coefficient < 0.01% per ºC, from 5 ºC to
40 ºC
Maximum altitude 2000 m (6562 ft) to full safety
specifications
Display size/type Main 5 digit + 2 x 5 digit
secondary displays
Battery type 6 V, 7Ah sealed lead acid
Voltage input range 100 - 240 V 50 / 60 Hz 90 VA
Charge time 8 hours
Backlight LED backlight
Battery life >1000 Auto (3 sec) tests
Auto power down 300s
Mode selection Rotary switch
Range selection Rotary switch
Memory features selection Rotary switch
Weight 6.7 kg
Case dimensions L315 mm x W285 mm x
H181 mm
Pouch for test leads Yes (lid mounted)
Test leads included depending on
chosen option:
DH4C lead set
KC1 Kelvin Clip lead set
IP rating IP65 case closed, IP54 battery
operation
Record storage 200 test records
Safety rating
In accordance with IEC61010-1, CATIII 300V when used
with optional terminal cover (details in ordering information)
Operating temperature and humidity
-10 °C to +50 °C
(14 °F to 122 °F) <90% RH
Reference conditions 20 °C ±3 °C
Storage temperature and humidity
-25 °C to +60 °C, <90% RH
EMC
In accordance with IEC61326-1 (Heavy industrial)
Noise rejection
Less than 1% ±20 digits additional error with 100 mV peak
50/60 Hz. on the potential leads. Warning will show if hum
or noise exceeds this level.
Maximum lead resistance
100 mΩ total for 10 A operation irrespective of battery
condition.

4
DLRO10HDX
10 A Digital Low Resistance Ohmmeter
OPTIONAL TERMINAL COVER
The CAT III 300 V rating
on the DLRO10HDX is only
valid when the instrument
is fitted with the optional
terminal cover to provide
the required creepage and
clearances at the instrument
terminals. Although the
terminal cover may be used
with any test leads, only the Megger DH4, DH5 and DP1-C
duplex handspikes, and KC2-C insulated kelvin clips have
suitable probe insulation to comply with the requirements of
IEC61010-1 and the CATIII 300 V rating.
SUPPLIED LEADSET OPTIONS
DLRO10HDX
+ KC1 Kelvin clip 3 m leads
+ No test leads supplied
+ DH4-C probe 1.5 m leads

5
DLRO10HDX
10 A Digital Low Resistance Ohmmeter
Back light -
for low light
conditions
Contrast for
clear visibility
Mains power
LED
Display clearly
showing large digits
for test results and
visible in all light
conditions
Single button to save
test results and to
automatically save in
auto mode
IP54 for protection
against dust and
rain during testing
CONNECTORS
C1-C2
P1-P2
USB for
downloading
Hazard warning
LED during test
Quick and easy
rotary switch
selection of test
modes.
- no
configuration
required
Rotary switch
selection of view,
download and
delete test results
Setting for
time and date
Simple
navigation
of setup
and stored
results
Test button
to start and
stop test
Rotary switch
selection of
test modes and
off position

6
DLRO10HDX
10 A Digital Low Resistance Ohmmeter
Model name Language Plug/Mains lead
DLRO10HDX - - L G - P
SELECT A LEADSET
NLS (No Leadset)
DH4C (DH4-C probe 1.5 m leads)
KC1-TL3-C (KC1 Kelvin clip 3 m leads)
SELECT A LANGUAGE AND PLUG
Please note only some plug types are available for certain languages - the language you need will determine the mains leads available
LANGUAGE PLUG TYPES AVAILABLE
3 DIGIT
CODE
LANGUAGE
INCLUDED
UK EU US CH AUS IT IN UK + US
LG1 EN, DE, FR, NL P1 P2 - P4 P5 - - -
LG2 EN, ES, PT, IT P1 P2 P3 - - P6 - -
LG3 EN, AR, TR, FR P1 P2 P3 - - - P7 -
LG4 EN, CZ, SK, PL P1 P2 - - - - - -
LG5 EN, CN, JA, KO P1 P2 P3 - - - - P8
LG6 EN, RU, HU, RO - P2 - - - - - -
LG7 EN, NO, SV, FI - P2 - - - - - -

SALES OFFICE
Megger Limited
Archcliffe Road Dover
CT17 9EN England
T [phone]
E [e-mail]
DLRO10HDX_DS_en_V08
www.megger.com
ISO 9001
The word ‘Megger’ is a registered trademark
DLRO10HDX
10 A Digital Low Resistance Ohmmeter
ORDERING INFORMATION
Item (Qty) Order No.
DLRO10HDX Configured*
* See ordering configuration on previous page
Standard included accessories
DLRO10HDX user guide CD
Optional Accessories at extra cost
Calibration Shunt,10 Ω, current rating 1 mA. 249000
Calibration Shunt, 1 Ω, current rating 10 mA. 249001
Calibration Shunt, 100 mΩ current rating 1A. 249002
Calibration Shunt, 10 mΩ current rating 10 A. 249003
Certificate of Calibration for Shunts, NIST CERT-NIST
Replacement tips for DH4 and DH5 handspikes.
Needle point 1008-024
Replacement tips for DH4 and DH5 handspikes.
Serrated end 1010-929
Transport case 1009-744
Optional Test Leads at extra cost
Normal test leads not fitted with in-line connector:
Industrial application kit 1011-376
Terminal cover (use in conjunction with DH4 test leads
supplied as standard, or optional DH5 test leads for
CATIII 300 V compliance) 1002-390
Duplex Handspikes (2) with spring loaded helical contacts.
2m/7ft 242011-7
DH1 2.5m/8ft 1006-442
DH1 5.5m/18ft 242011-18
DH2 6m/20ft (only 1 lead supplied) 1006-443
DH2 9m/30ft (only 1 lead supplied) 242011-30
6m ext 1006-460
Straight Duplex Handspikes (2) Heavy Duty with fixed
contacts. 2m/7ft 242002-7
Straight Duplex Handspikes (2) Heavy Duty with fixed
contacts 5.5m/18ft 242002-18
Test lead pouch (lid mounted) 1005-623
Item (Qty) Order No.
Straight Duplex Handspikes (2) Heavy Duty with
fixed contacts 9m/30ft 242002-30
Duplex Heavy Duty 5cm (2”) C-Clamps. (2)
2m/7ft 242004-7
Duplex Heavy Duty 5cm (2”) C-Clamps. (2)
5.5m/18ft 242004-18
Duplex Heavy Duty 5cm (2”) C-Clamps. (2)
9m/30ft 242004-30
Duplex handspikes with replaceable
Needle Points 2m/7ft 242003-7
Duplex 1.27 cm (1/2 “) Kelvin Clips. (2)
gold plated 2m/7ft 241005-7
Duplex 1.27 cm (1/2 “) Kelvin Clips. (2)
silver plated 2m/7ft 242005-7
Duplex 3.8 cm (11/2”) Kelvin Clips. (2)
2m/7ft 242006-7
Duplex 3.8 cm (11/2”) Kelvin Clips. (2)
5.5m/18ft 242006-18
Duplex 3.8 cm (11/2”) Kelvin Clips. (2)
9m/30ft 242006-30
Single handspike (1) for potential measurement.
2m/7ft 242021-7
Single handspike (1) for potential measurement.
5.5m/18ft 242021-18
Single handspike (1) for potential measurement.
9m/30ft 242021-30
Current clip (1) for current connections.
2m/7ft 242041-7
Current clip (1) for current connections
5.5m/18ft 242041-18
Current clip (1) for current connections
9m/30ft 242041-30
Note: For more details of optional leadsets see separate test lead
datasheet DLRO_TL_DS_V##.pdf
For detailed information on connecting lead accessories refer
to the supplied “accessory important information sheet”
(DLROTestLeads--2007-431_UG_EN-DE-FR-ES-IT_V##)