NDB Technologies LRM-10 User manual

NDB TECHNOLOGIES INC.
LRM-10 micro-ohmmeter
MU033-GEN-ENG Version 1.4
LRM-10
User Manual

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Table of Contents
Contact Us.................................................................................................................. 3
Safety Warnings......................................................................................................... 3
Safety Symbols....................................................................................................... 3
Safety Precautions ................................................................................................. 4
Introduction ............................................................................................................... 4
Kit content ................................................................................................................. 4
Technical specifications ............................................................................................. 5
Overview.................................................................................................................... 6
Settings ...................................................................................................................... 7
Operation................................................................................................................... 8
Modes .................................................................................................................. 10
Start a new measurement ....................................................................................... 11
Accessories and spare parts..................................................................................... 11
Dual hands probes ............................................................................................... 13
Kelvin clamp probes............................................................................................. 14
Exothermic Cadweld® probe................................................................................ 15
Temporary grounding jumper tester ................................................................... 16
Resistor sample.................................................................................................... 17
Protection and transport ..................................................................................... 18
Data transfer............................................................................................................ 19
Batteries................................................................................................................... 21

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Contact Us
Phone [phone]
Address 1405 St-Jean-Baptiste Avenue, office 111
Quebec, QC G2E 5K2
Canada
Web Site www.ndbtech.com
Technical Support 1 [phone]
9AM to 4PM, Eastern Time (GMT -5)
Email: [email protected]m
Safety Warnings
Follow all the safety rules to avoid dangerous electric shocks. Only properly
trained personnel should use the LRM-10 micro-ohmmeter. Safety is the
responsibility of the user.
Read all safety and operating instructions before to use the equipment.
Retain this User Manual for future reference.
Heed all safety warnings on the equipment and in the manual.
Follow all operating instructions.
Safety Symbols
Hazard symbol referring to the instruction manual: The product is
marked with this symbol when it is necessary for you to refer to the
instruction manual in order to protect yourself against personal
injury or to protect against damage to the product.
The hazardous high voltage symbol alerts you of the presence of an
un-insulated voltage with enough magnitude to produce an electric
shock.

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Safety Precautions
Do not use the LRM-10 micro-ohmmeter in an explosive area.
Stand clear of all parts of the high-voltage circuit, including all
connections, unless the test set is de-energized and all parts of the test
circuit are grounded.
Keep other people away from test activities with suitable barricades or
warnings.
Treat all terminals of high-voltage power equipment as potential electric
shock hazards. Voltages may be induced at these terminals because of
proximity to energized high-voltage lines or equipment.
Maintenance must be performed by qualified personnel who are familiar
with the construction and operation of the test set and the hazards
involved.
Only use the rechargeable batteries approved by ndb Technologies. Using
any other brand/model of rechargeable batteries in this instrument can
cause excessive heat, damage the batteries, damage the instrument,
cause fire or explosion. If the rechargeable batteries needs to be replaced,
contact ndb Technologies to order a new set. Refer to the Battery
replacement section of this manual for more details.
Introduction
The LRM-10 is a high precision micro-ohmmeter that can be paired with a great
variety of accessories. Many applications are available such as low resistance
measurement on circuit breakers, soldering, connectors, wires, metal plates,
battery inter-cell connections, Cadweld® exothermic soldering, etc…
Kit content
The kit content is described below:
LRM-10 digital micro-ohmmeter
Six rechargeable NiMH AA batteries
Battery charger
Set of dual hand probe LRM-4015HD
Nylon mesh protective bag
Set of standard measuring cables with clips (DRM-403)
Communication cable and adapter
Calibration certificate
User Manual

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Technical specifications
LRM-10
Measuring range
0.01µto 200
Display
LCD display 128 x 64 pixels
Current
10A, 250mA, 5mA
Resolution
0.01 µΩ
Power supply
Six AA NiMH batteries
Autonomy
(number of measurements)
12 000 at 10A, 10 000 at other currents
Operating temperature
-20°C to 50°C*
Charging temperature
0° to 50°C
Storage temperature
-40°C to 50°C
Humidity
0 to 95% non-condensing
Weight
0.86kg
Dimensions
203 x 114 x 51 mm
*Using the instrument below 0°C shortens the battery duration time. Cable
length can also affect battery duration time. The instrument’s accuracy remains
unaffected.
LRM-10 –Scales
Scale
Current
Measurement
error
Scale Error
Common mode reject
error
200 Ω
5mA
0.1%
± 2 counts
0.02 Ω
-
-
20 Ω
5mA
0.1%
± 2 counts
0.002 Ω
-
-
2 Ω
250mA
0.1%
± 2 counts
0.0002 Ω
-
-
200 mΩ
250mA
0.1%
± 2 counts
0.02 mΩ
-
-
20 mΩ
10A
0.1%
± 2 counts
0.002 mΩ
-
-
2 mΩ
10A
0.1%
± 2 counts
0.0002 mΩ
-
-
200 µΩ
10A
0.1%
± 2 counts
0.02µΩ
± 2 counts
0.02µΩ
20 µΩ
10A
0.1%
± 2 counts
0.02µΩ
± 2 counts
0.02µΩ

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Overview
The figure below shows an overview of the LRM-10 features.
1. Probe connector: Allows the user to connect a probe to the LRM-10
micro-ohmmeter.
2. Charger & RS232 communication port:Allows charging the batteries
and transferring the measurement data to a computer.
3. I/O button: Press to turn ON or OFF the instrument.
4. Backlight button: Press to activate the display backlight.
5. Mode button: Press to change the measurement mode.
6. Display: The LCD screen displays the measurement data.
7. Go button: Press to start a new measurement.
8. Battery compartment: Only use the recommended batteries.

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Settings
Follow the steps below to adjust the instrument’s settings.
Turn ON the instrument by pressing the I/O button.
Press and hold (approximately 6sec) the MODE button until the System
Menu appears, see figure below.
Press the MODE button to select the parameter to set.
oFrequency: Select the electric network frequency where the
LRM-10 micro-ohmmeter will be used (50Hz or 60Hz). This
feature allows a reduction of the reading errors due to nearby
electromagnetic induction on the test leads.
oLanguage: Select the preferred language between English and
French.
oContrast: Adjust the display’s contrast.
Press the Backlight button or the GO button to set the parameter.
When completed, press and hold (approximately 6sec) the MODE
button until the System Menu disappears.

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Operation
Connect the test leads to the LRM-10 micro-ohmmeter. Make sure to
connect each lead in the proper connector of the same color, on the
LRM-10 micro-ohmmeter.
The yellow and green clips are installed to both extremity of the device
under test. They allow a pulsed current to travel through the device
under test.
The red and black clips are installed between the two current injection
points (yellow and green). The instrument will measure the voltage
drop between the red and black clips. The instrument will then be able
to measure the resistance between the red and black clips. See figure
below:

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The result is shown on the display, see the above figure.
To manually start a new measurement, press the GO button.
If the LRM-10 detects a bad connection, the ‘’BAD CONNECTION’’ error
message will be displayed. In this case, check the quality of contact of
each clip.

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Modes
The LRM-10 instrument features five modes:
Standard mode: Allows taking a resistance measurement and displaying the
reading.
Relative mode: A reference measurement is taken in the standard mode, and
then the instrument is switched to the relative mode by pressing the MODE
button. Taking a second measurement will display the resistance difference
between the two readings.
Example: A measurement was taken in the standard mode (692.8 micro-ohms).
The MODE button was pressed to select the relative mode. A new measurement
was taken. The difference between the previous reading and the new reading is
displayed (209.03 micro-ohm). The value in the red rectangle is the reference
reading, previously taken in the standard mode.
Relative % mode: Similar to the relative mode, the Relative % mode displays the
resistance difference between the two readings, in percentage.
Motor mode: Allows measuring the winding resistance in a very small coil. This
mode increases the output’s duty cycle in order to saturate the measured coil.
OK/X mode: Allows showing the difference between the previous reading taken
in the standard mode, and the new measurement taken in the OK/X mode.
After the reading is taken in the standard mode, press the MODE button until
you reach the OK/X mode, then take a new measurement by pressing the GO
button. If the new reading is lower than the reading from the standard mode,
the LRM-10 displays OK, otherwise, it displays X.

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Start a new measurement
To start a new measurement, the user can press the GO button on the
instrument’s keypad.
Another way to start a new measurement is to momentarily (~1 sec) short the
blue and green connectors. This feature allows the integration of the LRM-10
micro-ohmmeter in a more complex system where it could be controlled, for
example, by a computer or an N/O (normally open) switch.
Accessories and spare parts
The following accessories are available for the LRM-10 micro-ohmmeter.
Item number
Description
Figure
NDB-HSC
Hard shell case
DRM-4014
Nylon mesh protective
bag
(micro-ohmmeter not
included)
DRM-403
Set of standard
measuring cables with
clips

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DRM-4015
Double hands probe
with replaceable tips
DRM-4015-
2MM
2MM tip for DRM-
4015 or LRM-4015HD
DRM-4015-SP
Long spring pin
adapter for DRM-4015
and LRM-4015HD
DRM-4040-
Set of four pins for
DRM-4015 and LRM-
4015HD
LRM-4015HD
Dual hand test probe,
heavy duty version,
with replaceable tips
DRM-4017-19
Kelvin clamps 19mm
(3/4’’)
DRM-4017-35
Kelvin clamps 35mm
(1 3/8’’)
DRM-4012
Exothermic welding
test probe (Cadweld®
test)
DRM-4013
Sample resistance 9.5
micro-ohm
GET-40
Temporary ground
cable test set
GET-401
Torque wrench and
socket for GET-40
XDP-103 and
XDP-104
Data transfer kit (cable
and RS232 to USB
converter)
NDB-BAT
Battery replacement
kit for LRM-10

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Dual hands probes
The DRM-4015 and LRM-4015HD probes are easy to use on any metallic surface.
Their spring loaded tips allows a good electrical contact on the conductor to
test. The next figure shows the DRM-4015 probes on a metallic surface. The
black dots (DRM-4015) or red dots (LRM-4015HD) should always be facing one
another while performing the test. This ensures that the voltage reading points
are inside the current injection points.
After multiple usages, the probe’s tips can start to round which leads to bad
electrical contact. To replace the pins, gently pull them out of the probe using
long noise pliers. Insert the new pins using the same technique.

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Some applications require applying the probe’s tips on limited space. The DRM-
4015-2MM (figure below top) or DRM-4015-SP (figure below bottom) can be used
to achieve this task. To install these adapters, simply remove the standard pins
from the probe, and insert the adapter of your choice.
DRM-4015-2MM installed on a DRM-4015 probe:
Kelvin clamp probes
The DRM-4017-19 and DRM-4017-35 kelvin probes are used with the LRM-10
micro-ohmmeter to measure resistance on cables, rods, or any other metallic
surface. They integrate the four terminals measurement technique.

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Exothermic Cadweld® probe
The DRM-4012 probe is designed to allow testing Cadweld® exothermic welding
with the LRM-10 micro-ohmmeter. Its special design allows repeatable readings
and easy handling.
Note: A sample resistor may be used to test Cadweld® welding in relative mode.

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Temporary grounding jumper tester
The GET-40 device is an easy-to-use and accurate Grounding Jumper Tester
using four points measuring method. The micro-ohmmeter is installed on top of
the GET-40, and the test cables are connected on top of it.

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Resistor sample
Resistor samples are available to facilitate the use of the LRM-10 micro-
ohmmeter in relative mode. The sample is used to take the initial measurement
and to set the reference value. Then, the instrument can be used to measure
the unit(s) under test in the relative mode. Refer to the mode section of this
manual for more details.
Next figure shows the DRM-4013 (9.5µ) installed on the LRM-10 micro-
ohmmeter.
Note: Resistor samples are not as precise as calibration shunt resistors.
Therefore, they should not be used to validate the instrument precision.

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Protection and transport
The DRM-4014 nylon mesh bag and NDB-HSC transportation case are designed
to protect the LRM-10 micro-ohmmeter from on water, dirt and impacts that
could damage the instrument. Using such protection is suggested to preserve
your LRM-10 micro-ohmmeter.

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Data transfer
The LRM-10 features the capability to send reading data to a computer using its
serial communication port (the same connector is also used to charge the
batteries).
Connect the LRM-10 micro-ohmmeter to a PC computer using the XDP-
103 and XDP-104 accessory. See next figure:
In Windows, open the Control Panel.
Open Device Manager.
Select the Serial Port.
Configure the Serial Port:
oBits per second: 19200
oData bits: 8
oParity: None
oStop bit: 1
oRow control: None

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Start the serial communication software of your choice.
Start taking measurement on the LRM-10 micro-ohmmeter, the values
are shown on the serial communication software.