AEMC 6255 Operating Manual
ENGLISH
■
MICRO-OHMMETER
6255
User Manual
Statement of Compliance
Chauvin Arnoux®, Inc. d.b.a. AEMC® Instruments
certifies that this instrument has been calibrated using
standards and instruments traceable to international
standards.
We guarantee that at the time of shipping your
instrument has met its published specifications.
An N.I.S.T. traceable certificate may be requested at
the time of purchase, or obtained by returning the
instrument to our repair and calibration facility, for a
nominal charge.
The recommended calibration interval for this
instrument is 12 months and begins on the date of
receipt by the customer. For recalibration, please use
our calibration services. Refer to our repair and
calibration section at www.aemc.com
Serial #:
.
Catalog #: 2129.84
Model #: 6255
Please fill in the appropriate date as indicated:
Date Received:
Date Calibration Due:
Chauvin Arnoux®, Inc.
d.b.a AEMC
®
Instruments
www.aemc.com
2 Micro-Ohmmeter Model 6255
CONTENTS
1. INTRODUCTION ............................................................................................ 4
1.1. Precautions ......................................................................................... 4
1.2. Battery Handling .................................................................................. 5
1.3. Definition of Measurement Categories (CAT) ...................................... 5
1.4. Receiving Your Shipment .................................................................... 6
1.5. Ordering Information ........................................................................... 6
2. FEATURES .................................................................................................... 7
2.1. Description .......................................................................................... 7
2.2. Applications ......................................................................................... 7
2.3. Key Features ....................................................................................... 8
2.4. Control Features .................................................................................. 9
2.5. Button Functions ............................................................................... 10
2.6. Display Symbols ................................................................................ 11
3. SPECIFICATIONS ....................................................................................... 13
3.1. Electrical ............................................................................................ 13
3.2. Mechanical ........................................................................................ 14
3.3. Display............................................................................................... 14
3.4. Environmental ................................................................................... 14
3.5. Safety ................................................................................................ 14
4. OPERATION ................................................................................................ 15
4.1. Quick Summary ................................................................................. 15
4.2. Instrument Configuration (SET-UP Mode) ......................................... 17
4.3. Operating Procedure ......................................................................... 26
4.4. Selecting the Test Range .................................................................. 28
4.5. Measurement Modes ......................................................................... 29
4.6. Ambient Temperature Compensation ................................................ 33
4.7. Activating Alarms ............................................................................... 36
5. MEMORY/PRINTING ................................................................................... 37
5.1. Managing and Printing the Data in Memory ...................................... 37
5.2. Displaying and Printing Stored Measurements .................................. 38
5.3. Cables and Printers Used with the Interface Port .............................. 40
6. DATAVIEW .................................................................................................. 42
7. TROUBLESHOOTING ................................................................................. 43
7.1. Fault Indicators .................................................................................. 43
8. APPLICATION EXAMPLES ........................................................................ 44
8.1. Measuring Winding Resistance of Motors and Transformers ............ 44
8.2. Measuring Resistance on Electric Motors ......................................... 45
8.3. Battery Strap Measurements ............................................................. 45
9. MAINTENANCE ........................................................................................... 46
9.1. Warning ............................................................................................. 46
9.2. Cleaning ............................................................................................ 46
9.3. Charging/Recharging the Batter y ...................................................... 46
9.4. Battery and Fuse Replacement ......................................................... 47
REPAIR AND CALIBRATION ........................................................................... 48
TECHNICAL AND SALES ASSISTANCE ....................................................... 48
LIMITED WARRANTY ...................................................................................... 49
Micro-Ohmmeter Model 6255 3
instructions whenever this danger symbol appears.
In the European Union, this product is subject to a separate collection
accordance with directive WEEE 2002/96/EC
1. INTRODUCTION
Thank you for purchasing the AEMC Micro-Ohmmeter Model 6255. For best
results from your instrument and for your safety, read the enclosed operating
instructions carefully and comply with the precautions for use. These products
must be only used by qualified and trained users.
WARNING, risk of DANGER! The operator must refer to these
CAUTION! Risk of electric shock. The voltage at the parts marked
with this symbol may be dangerous.
Equipment is protected by double insulation.
Battery
Important instructions to read and to fully understand.
Useful information or tip to read.
Compliance with the Low Voltage & Electromagnetic Compatibility
European directives (73/23/CEE & 89/336/CEE)
system for recycling electrical and electronic components In
1.1. Precautions
Refer to the following warnings to ensure personnel safety and proper instrument
operation.
Read the user manual before performing any tests with this instrument .
Only test de-energized circuits. Never connect to a live circuit.
When measuring resistance with a high inductive component
(transformers, motors, etc.), after ending the measurement the
instrument discharges the inductive sample and the warning icon
appears for the entire duration. Never disconnect the connection wires
before this icon disappears.
Do not use the instrument in an explosive environment, including poorly
ventilated battery rooms and enclosures.
Ensure the battery is fully charged prior to testing. If unused for several
months, recharge the battery. (We recommend monthly recharging.)
Use only direct replacements for blown fuses.
Do not use alcohol or oil based cleaner s when cleaning the instrument.
Only use soapy water with a damp cloth or sponge.
Test leads and measuring wires must be in good condition; replace
immediately if there is any deterioration (insulation split, burnt, etc.).
Never exceed the safety values indicated in the specifications.
4 Micro-Ohmmeter Model 6255
1.2. Battery Handling
Your instrument is equipped with a NiMH battery. This technology offers
several advantages:
Long battery charge life for a limited volume and weight.
Possibility of quickly recharging your battery.
Significantly reduced memory effect: you can recharge your battery
even if it is not fully discharged.
Respect for the environment: no pollutant materia ls suc h as lead or
After prolonged storage, the battery may be completely discharged. If so, it
must
battery may take several hours. The instrument cannot be used when the
battery is being recharged.
To maximize battery life:
NiMH technology allows a limited number of charge/discharge cycles
depending significantly on:
See §9 for battery replacement instructions.
cadmium, in compliance with the applicable regulations.
be completely recharged. Full recharging of a completely discharged
At least 5 charge/discharge cycles will be necessary for your battery
to recover 95% of its capacity.
Only charge your instrument at temperatures between 32° and 104°F
(0° and 40°C).
Comply with the conditions of use defined in this user manual.
Comply with the storage conditions specified in this user manual.
The conditions of use.
The charging conditions.
Do not dispose of the battery pack with other solid waste. Used
batteries must be entrusted to a qualified recycling company or to a
company specialized in processing hazardous materials.
1.3. Definition of Measurement Categories (CAT)
CAT IV Measurement category IV corresponds to measurements taken at
the source of low-voltage ins tallations.
Example: power feeders, counters and protection devices.
CAT III Measurement category III corresponds to measurements on
building installations.
Example: distribution panel, circuit-breakers, machines or fixed
industrial devices.
CAT II Measurement category II corresponds to measurements taken on
circuits directly connected to low-voltage installations.
Example: power supply to domestic electrical appliances and
portable tools.
Micro-Ohmmeter Model 6255 5
1.4. Receiving Your Shipment
Upon receiving your shipment, make sure that the contents are consistent
with the packing list. Notify your distributor of any missing items. If the
equipment appears to be damaged, file a claim immediately with the carrier
and notify your distributor at once, giving a detailed description of any
damage. Save the damaged packing container to substantiate your claim.
1.5. Ordering Information
Micro-ohmmeter Model 6255 …..………...........................….... Cat. #2129.84
Includes extra-large tool bag, set of two 10 ft. (3m) Kelvin clips (10A - Hippo),
set of two 10 ft. (3m) Kelvin probes (1A - Spring Loaded), one RS-232 DB9
F/F 6 ft. null modem cable, RS-232 to USB adapter, US 115V power cord,
quick reference guide, NiMH rechargeable 6V battery pack, and USB thumb
drive supplied with user manual and DataView
Replacement Parts:
Kelvin Clips 10 ft. (3m) 10A-Hippo..…….……................…......... Cat. #1017.84
Kelvin Probes 10 ft. (3m) 1A Spring Loaded ….............…......... Cat. #2118.73
Adapter - RS-232 to USB 2.0 Adapter.
Cable - PC RS-232 DB9 F/F 6 ft. (1.8m) Null Modem Cable …. Cat. #2119.45
Replacement Battery 6V, 8.5 Ah rechargeable NiMH ……........ Cat. #2129.91
115V Power Cord ……………………………………….…..…...... Cat. #5000.14
Extra-large classic tool bag ………………….……………..…...... Cat. #2133.73
Fuse, set of 3, 16A/250V, 1 1/4 x 1/4" (6.3x32mm) fast blow … Cat. #2129.98
Fuse, set of 10, 2A/250V, 3/4 x 3/16" (5x20mm) fast blow ….... Cat. #2129.99
Accessories:
Kelvin Clips 20 ft. (6m) 10A-Hippo …............................…......... Cat. #2118.70
Kelvin Probes 20ft (6m) 1A Spring Loaded …............................ Cat. #2118.74
Kelvin Probes Pistol Grip 10 ft. (3m) 10A Spring Loaded …...... Cat. #2118.75
Kelvin Probes Pistol Grip 20 ft. (6m) 10A Spring Loaded …...... Cat. #2118.76
Kelvin Probes 10 ft. (3m) 10A Spring Load ed …........................ Cat. #2118.77
Kelvin Probes 20 ft. (6m) 10A Spring Loaded …........................ Cat. #2118.78
Kelvin Clips 10 ft. (3m) 1-10A …....................................…......... Cat. #2118.79
Kelvin Clips 20 ft. (6m) 1-10A …....................................…......... Cat. #2118.80
RTD temperature probe
RTD temperature probe with 7 ft. (2m) extension cable ............ Cat. #2129.96
Inverter – 12VDC to 120VAC 200 Watt for vehicle use ............. Cat. #2135.43
For the accessories and replacement parts, visit our web site:
www.aemc.com
…............................................…......... Cat. #2129.95
…......................…......... Cat. #5000.60
®
software..
6 Micro-Ohmmeter Model 6255
2. FEATURES
2.1. Description
The Micro-ohmmeter Model 6255 performs low resistan ce m easur eme nts
from 1μΩ
non-inductive resistances with test currents (continuou s or pulsed) from 1mA
to 10A. A built-in thermal switch protects the micro-ohmmeter against
overheating on the 10A range when in continuous use.
The large, easy-to-read liquid crystal display is 2.25 x 4.00". It displays the
value of resistance, metal type, reference and ambient temperatures (if
selected), alarm conditions (if selected), test current and range and test mode
(Resistive, Inductive or Auto). You can perform long measurement campaigns
(up to 60 minutes) at 10A
load charging (measurement stabilization in under 2 seconds).
The Model 6255 employs a four-wire Kelvin configuration, which eliminates
test lead resistance for a measurement accuracy of 0.05%. A built-in circuit
filters out AC signals. The instrument provides laboratory-level performance,
offering a high precision of 0.05% with a maximum resolution of 0.1μΩ over
seven ranges from 5mΩ to 2.5kΩ.
The Model 6255 is packaged in a sealed case. It provide s a rating of IP64 with
cover closed (IP53 with cover open) and locking metal measuring terminals.
The instrument is primarily a field device, but can also be used in a shop or
manufacturing process.
For operator safety and instrument protection, the instrument is fuse protected
at the inputs. Two fuses, accessible behind the front panel, protect against
stored energy in inductive loads. Enh anc ed internal circuitry protects against
possible inductive kickback when the current is shut off.
2.2. Applications
Some of the more popular and most frequent uses of the micro-ohmmeter are
in applications for:
to 2500Ω. Th is easy-to-use instrument measures all inductive or
. Other features include long battery life and fast
DC
Checking metallic coating resistance, especially in aeronautics
Ground connections and continuity measurement
Resistance measurements on motors and transformers
Contact resistance measurements on break ers and sw itche s
Component measurement
Electrical cable resistance measurement
Mechanical bond tests
Wire to terminal connections
Aircraft and rail bonds
Many other very low resistance samples
Micro-Ohmmeter Model 6255 7
2.3. Key Features
Measures from 1µΩ to 2500Ω
Test current selection from 1mA to 10A
RTD temperature measurement (optional)
Automatic or manual temperature compensation
Two programmable alarms with high or low triggering
Stores up to 1500 test results
Selectable Inductive or Resistive test modes
Operator safety by automatic discharge of residual charge on the
equipment under test
Instantaneous, continuous or mult ipl e test oper at ion
Selectable metal type (copper, aluminum or other) for temperature
compensation
Internal, rechargeable batteries conduct up to 5000 tests at 10A
A built-in battery pack recharger recharges the batteries by
connecting to the AC line (90V/264V, 45Hz/420Hz) using a standard
line cord
4-Wire measurement with automatic compensation of undesirable
voltages and lead resistance
Large multi-function backlit dis play
Direct display of the measurement with its unit s, range ,
measurement mode, and (if activated) temperature compensation.
Measurement can be initiated from the front panel or remotely
through the 9-pin communication port
Rugged, sealed case
8 Micro-Ohmmeter Model 6255
2.4. Control Features
Figure 2-1
1. Kelvin input terminals
2. AC line recharging receptacle
3. Large multi-line backlit liquid crystal display
4. RTD temperature input
5. Communication / remote operation port
6. Range selection switch
7. Test, Start/Stop button
8. Eight program / function buttons
Micro-Ohmmeter Model 6255 9
2.5. Button Functions
R ( )
In SET-UP mode, selects a function or increments a flashing
parameter.
In SET-UP mode, selects a function or decrements a flashing
parameter
In SET-UP mode, accesses the func tion to be modified.
In Wrap-Around mode, selects the parameter to be modified
(from left to right)
In SET-UP mode, shifts the decimal point and selects the unit.
2nd
PRINT
PRINT
MEM
R ( )
ALARM
METAL
MEM
MR
Activates the secondary function of a button. The symbol
appears on the left side of the display.
Immediate printing of the measurement to a serial printer. If the
temperature compensation function has been activated, the
calculated result and the temperatures involved are also
printed.
Retrieves stored data for printing (this function is independent
of the setting of the switch) except in the OFF and SET-UP
positions.
Activates or deactivates the temperature compensation
function to calculate the resistance measured at a temperature
other than ambient measurement temperature.
Activates or deactivates the alarms. High or low triggering
values are adjusted in SET-UP.
Selects the desired measurement mode prior to starting one of
the following measurements: Inductive mode (continuous
test), non-inductive mode (instantaneous test) or non-inductive
mode with automatic triggering (multiple tests).
Selects the metal type for the temperature compensation
calculation: Cu, Al, or Other metal.
Stores the measurement at an address identif ied by an objec t
number (OBJ) and a test number (TEST).
Two presses on this button are required, one to select the
location (use the ▲ and ► buttons to change the location) and
another to store the measurement.
Retrieves stored data (this function is independent of the
selector setting of the switch) except for the OFF and SETUP positions. Data is viewed using the ▲ and ► buttons.
The
Turns the display backlight ON or OFF.
, , and ALARM buttons can be used.
Activates or deactivates the buzzer and adjusts the sound
level.
10 Micro-Ohmmeter Model 6255
2.6. Display Symbols
Cu
The display incorporates two lines of characters to display test results, as well as
a library of symbols to assist the operator in determining conditions at a glance.
The symbols that can appear are shown in Figure 2-2 and are descri bed bel ow.
Figure 2-2
Buzzer ON.
Battery condition
R ( )
Al
Other metal
Temperature compensation ON
Copper metal type selected
Aluminum metal type selected
User defined metal type selected
Communication port active
ALARM 1
ALARM 1
ALARM 2
ALARM 2
OBJ.
TEST
°C / °F
PRINT
MEM
REMOTE
MR
Alarm 1 active with high set point
Alarm 1 active with low set point
Alarm 2 active with high set point
Alarm 2 active with low set point
First position locator for data stored in memory
Second position locator for data stored in memory
Temperature displayed in either degrees Centigrade or
Fahrenheit
Printing current test result or tests stored in memory
Displayed measurement about to be stored in memory
Instrument under computer control
Memory recall
Micro-Ohmmeter Model 6255 11
mV m
Ω
Units of measure
AUTO
ST BY
OPER
250Ω 10mA
2500mΩ 1A
250mΩ 10A
5mΩ 10A
2500Ω 1mA
25Ω 100mA
25mΩ 10A
Memory utilization indicator
Resistive material test mode selected
Inductive material test mode select ed
Repetitive test mode selected
System idle ready to start a test
Test in process
Second function of a button activated
CAUTION! Refer to the user manual before using the
instrument.
2500 ohm, 1 milliamp test range selected
250 ohm, 10 milliamp test range selected
25 ohm, 100 milliamp test range selected
2500 milliohm, 1 Amp test range selected
250 milliohm, 10 Amp test range selected
25 milliohm, 10 Amp test range selected
5 milliohm, 10 Amp test range selected
12 Micro-Ohmmeter Model 6255
Accuracy over 1 year
(23°C ± 5°C)
5mΩ
0.1µΩ
0.15% ± 1.0µΩ
10A
50mV
25mΩ
1µΩ
0.05% ± 3µΩ
10A
250mV
250mΩ
10µΩ
0.05% ± 30µΩ
10A
2500mV
2500mΩ
0.1mΩ
0.05% ± 0.3mΩ
1A
2500mV
25Ω
1mΩ
0.05% ± 3mΩ
100mA
2500mV
250Ω
10mΩ
0.05% ± 30mΩ
10mA
2500mV
2500Ω
100mΩ
0.05% ± 300mΩ
1mA
2500mV
3. SPECIFICATIONS
3.1. Electrical
Specifications are given for an ambient temperature of 73°F ± 9°F (23°C ± 5°),
relative humidity of 45 to 75% and a supply voltage of 6V ± 0.1V.
All specifications are subject to change without notice.
Measurement Method:
4-Wire Kel v in resistance measurement with compensation for stray/residual
voltages.
Measurement Ranges:
Range Resolution
73°F ± 9°F
Measurement
Current
Voltage Drop
Temperature Measurement: 3-wire 100Ω Platinum RTD
Accuracy: ± 0.5°C
Resolution: 0.1°C
Influence From Environment Conditions:
Temperature: 0.1% per 10°C typical, 0.25% max
Humidity: 0.5% max from 10 to 90%
Battery Voltage: ± 0.1% from 4.5 to 7.5V
Open Circuit Voltage: 7V
Operating Voltage: 5 to 6V
Power Source:
Rechargeable 6V, 8.5 Ah NiMH battery pack, built-in 90 to 256V (45 to
420Hz) charger
Battery Life: 5000 10A tests (typical)
Battery Charging: 120/240V
Auto-Pow er Off: when battery voltage <5.0V
Micro-Ohmmeter Model 6255 13
max
DC
DC
± 20% (45 to 400Hz) line voltage
AC
Low Battery Indication: The symbol is displayed when the battery needs
to be recharged
Overload Input Protection: 250Vrms
Fuses:
F1 - 1 1/4 x 1/4" (6.3 x 32mm), fast acting, 16A/250V current source protection
F2 - 3/4 x 3/16" (5 x 20mm), fast acting, 2A/250V charging circuit protection
3.2. Mechanical
Dimensions: 10.63 x 9.84 x 7.09" (270 x 250 x 180mm)
Weight: 8.1 lbs (approximately 3.69kg) without leads
Case Protection: ABS plastic polycarbonate: watertight to IP64 (cover closed),
water resistant to IP53 (cover open)
Color: Safety yellow case with gray faceplate
3.3. Display
Blue Electroluminescent backlit Liquid Crystal Display (LCD), 2.25 x 4.00" (57.2 x
102mm) with icons and two numeric fields for data presentation.
One numeric field contains 4 digits for displaying ambient and reference
temperature levels on the top line in “temperature compensation” mode. The
other contains 5 digits and is used to display the measured values on the bottom
line. Error messages are also listed on the bottom line.
3.4. Environmental
Operating Temperature:
14° to 132°F (-10° to 55°C), 10 to 80% (non-condensing)
Storage Temperature: -40° to 140°F (-40° to 60°C)
3.5. Safety
EN 61010-1, 50V, CAT III, Pollution Degree 2
Conducted and radiated emission:
EN 55022, class B
EN 61000-3-2
EN 61000-3-3
Immunity:
EN 61000-4-2 electrostatic discharges
EN 61000-4-3 radiated fields
EN 61000-4-5 shock
EN 61000-4-6 conducted disturbanc es
EN 61000-4-11 voltage drops
EN 61000-4-4 bursts
14 Micro-Ohmmeter Model 6255
4. OPERATION
Fully charge the instrument battery before use.
4.1. Quick Summary
The following is a summary instruction set that will assist the operator in
performing measurements. For complete details on each function and test
method refer to the operating procedure section (§ 4.3) and instrument
configuration section (§ 4.2) in this manual.
WARNING: Read and follow all safety warnings on page 4 before
operating this instrument.
1. Turn the instrument on and select a test range by turning the rotary
switch to the desired position. If the resistance of the device under test
is unknown, start with the highest range (2500Ω) and work down to
increase resolution as necessary.
2. Select the test method best suited for the measurement by pressing the
button to select inductive (continuous test), resistive
(instantaneous test) or AUTO (multiple testing).
3. Activate the backlight, if necessary, by pressing the button.
4. Activate the buzzer, if desired, by pressing yellow
the button.
5. Activate alarms, if desired, by pressing the yellow 2nd button followed by
the ALARM button. Successive presses of this two-button sequence will
select Alarm 1, Alarm 2 or both.
6. Select the metal type for the device under test by pressing the yellow
nd
2
button followed by the METAL button. Successive presses of this
two-button sequence will select Copper (Cu), Aluminum (Al) or Other
metal. This will be needed for temperature compensation.
7. Activate temperature compensation by pressing the R ( )
reference temperature will appear followed by the ambient temperature
on the top line of the display.
nd
2
button followed by
button. The
Micro-Ohmmeter Model 6255 15
8. Start the test by pressing the START/STOP button. The resistance
reading will appear on the lower line of the display. The symbol OPER
will appear on the lower left to indicate that a test is in process. The
Stand-by symbol ST BY will appear when the test is completed.
Resistive element tests will stop automatically. Inductive and AUTO
testing will stop when you push the START/ STOP button a second
time.
9. Store the test result in memory by pressing the MEM button at the
conclusion of a test. The next available location will be presented on the
top line of the display. To use this location, press the MEM button a
second time.
10. Recall readings from memory by pressing the yellow
by the MEM button. The last measurement stored in location OBJ: X
TEST: X will be displayed.
Use the ▲, ▼ and ► buttons to select the object and test memory
location to review. All information from the measurement is availabl e for
review including metal type, ambient and reference temperatures,
resistance at ambient and reference temperatures, test range and test
current.
nd
2
button followed
Typical Operational Display
Figure 4-1
16 Micro-Ohmmeter Model 6255
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