MEGGER DLRO 10, DLRO 10X User Manual

DLRO 10 and DLRO 10X

Digital Microhmmeter

DESCRIPTION

DLRO 10 and DLRO 10X set the standards for low resistance
measurement. DLRO 10 and DLRO 10X are fully automatic
instruments, selecting the most suitable test current up to 10A d.c.
to measure resistance from 0.1 µΩ to 2000 Ω, on one of seven
ranges.

For users who desire more control over the measurement process,
DLRO 10X uses a menu system controlled by a two-axis paddle to
allow the user to manually select the maximum test current.

DLRO 10X also adds real time download of results and on board
storage for later download to a PC.

Both instruments are built into a strong, lightweight case that is
equally at home in the field or in the laboratory. Light enough to
be worn around the neck, they are small enough to be taken into
areas that were previously too small to access.

DLRO 10 uses a large, bright 4 1/2 -digit LED display while DLRO
10X has a large, backlit LCD display. Normally, measurements are
made with forward and reverse currents to cancel the effects of
any standing voltages across the test sample.

The average value is then displayed within 3 seconds, to a basic
accuracy of 0.2%. DLRO 10X displays both forward and reverse
measurements as well as the average of the two.

DLRO 10X allows the user to set high and low pass limits, thereby
enabling simple go-no-go testing.

At the end of a test DLRO10X will store the test results, as well as
any notes relevant to the test.

To assist operator safety and ease of use, both instruments are
supplied complete with a pair of duplex handspikes with 1.2 m
(4 ft) leads. One of the probes is fitted with LED’s, which
duplicate indicators on the instrument display indicating that all
four contacts have been made, the presence of a high voltage
across the load, and the presence of current flow while a load is
discharging. A full range of test leads is available with probes,
clamps and Kelvin clips.

Nickel Metal Hydride (NiMH) batteries power the instruments.
The battery packs are interchange-able so that an exhausted
battery may be recharged using the external charger supplied
while testing continues using a spare pack. Although full charging
will take 4 hours, a fast charge mode allows the battery to be 90%
charged within 2 1/2 hours from a 12 volt battery or from a
standard 120/230 V AC supply via the supplied charger. The
battery pack contains its own battery state indicator, which allows
the charge-state to be monitored, even without being connected
to the instrument.

DLRO 10X is fitted with RS232 communications that will allow
results to be downloaded in real time or stored for later retrieval.

Up to 700 sets of results may be stored within DLRO 10X
complete with notes containing up to 200 characters which may
be added using the on board keypad. These results can also be
downloaded to a PC.

MEASUREMENT MODES:

A variety of measurement modes are available. Since the
introduction of V2.0 firmware, Normal, Auto, Continuous and
Inductive mode are available on both the DLRO 10 and the
DLRO 10X.

■

Auto current reversal cancels standing
emfs

■

Protected to 600 V

■

Automatically detects continuity in
potential and current connections

■

Multiple operating modes including fully
automatic

■

Alpha-numeric keypad for entering test
notes (DLRO 10X)

■

User selectable high and low limits
(DLRO 10X)

■

Printer output and memory (DLRO 10X)

DLRO 10 AND DLRO10X

Digital Microhmmeter

DLRO 10 AND DLRO 10X

Digital Microhmmeter

FEATURES AND BENEFITS

■ Small, lightweight and portable - can be used in tight places,

reduces the need for extra long leads and two person
operation.

■ Four terminal resistance method shows the true resistance of

the item under test.

■ Bright LED (DLRO 10) and LCD (DLRO 10X) displays are easily

visible under all lighting conditions and reduce human error.

■ Automatically applies forward and reverse currents which cancel

out any standing voltages across the sample under test.

■ Checks for undue noise during measurement, reducing the

possibility of recording the incorrect result.

■ Automatically detects continuity in P and C circuits, preventing

erroneously high reading to be taken due to high resistance
contact.

■ Battery module has a battery condition indicator allowing the

user to check the state of spare batteries without connecting to
the instrument.

■ RS232 connector on the DLRO 10X allows downloading of

results in real time or stored for later retrieval.

DLRO 10 will display the average of the measurements achieved
using forward and reverse current, while DLRO 10X displays both
individual measurements and the average.

Normal mode initiates a test by pressing the Test button on the
instrument front panel after connecting the test leads. Continuity
of all four connections is checked, forward and reverse currents
are applied.

Auto mode allows forward and reverse current measurements to
be made and the average displayed simply by making contact
with all four probes. This mode is ideal when working with the
supplied handspikes. Each time the probes are removed and
reconnected to the load another test will be performed without
the need to press the test button on the instrument.

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 3 seconds until the
circuit is broken.

Inductive mode is intended for use when measuring inductive
loads. When measuring inductive loads it is necessary to wait for
the voltage to stabilise. This means that the measurement could
take a few seconds or several minutes. The test leads are firmly
connected to the item to be measured and the Test button is
pressed. The instrument will pass a current through the sample
and wait for the voltage to stabilise. If possible the current will be
increased. This procedure will be repeated until the voltage
detected falls into the range 15 mV to 200 mV. The instrument will
then continue to take readings, which will gradually decrease to
the true value as the voltage stabilises further. The operator
decides when the result is stable and presses the Test button to
terminate the test. Measurement is made with forward current only.

Unidirectional mode, on DLRO 10X only, applies a current in
one direction only. This does not enable any standing emfs to be
negated but speeds up the measurement process. Test starts
automatically when probes are connected.

APPLICATIONS

The needs for accurate low resistance measurement are well
known and very diverse. They range through Goods Receiving
inspection of components to ground bonding and welded joints.
Typical applications include, but are not limited to, making d.c.
resistance measurements of:

■ Switch and contact breaker resistance

■ Busbar and cable joints

■ Aircraft frame bonds and static control circuits

■ Integrity of welded joints

■ Inter-cell connections on battery systems up to 600 V peak

■ Quality control of resistive components

■ Transformer and motor winding resistance

■ Rail and pipe bonds

■ Metal alloys, welds and fuse resistance

■ Graphite electrodes and other composites

■ Wire and cable resistance

■ Transmitter aerial and lightning conductor bonding

The DLROs are light enough to be worn around the neck. They
are also small enough to be taken into areas which were
previously too cramped for easy testing.