AEMC 6255 User manual

ENGLISH
User Manual
■
MICRO-OHMMETER
6255
www. .com [e-mail]1.800.561.8187

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.
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
2Micro-Ohmmeter Model 6255
www. .com [e-mail]1.800.561.8187

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 Battery......................................................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
www. .com [e-mail]1.800.561.8187

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
instructions whenever this danger symbol appears.
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)
In the European Union, this product is subject to a separate collection
system for recycling electrical and electronic components In
accordance with directive WEEE 2002/96/EC
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 cleaners 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.
4Micro-Ohmmeter Model 6255
www. .com [e-mail]1.800.561.8187

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 materials such as lead or
cadmium, in compliance with the applicable regulations.
After prolonged storage, the battery may be completely discharged. If so, it
must
be completely recharged. Full recharging of a completely discharged
battery may take several hours. The instrument cannot be used when the
battery is being recharged.
At least 5 charge/discharge cycles will be necessary for your battery
to recover 95% of its capacity.
To maximize battery life:
 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.
NiMH technology allows a limited number of charge/discharge cycles
depending significantly on:
 The conditions of use.
 The charging conditions.
See §9 for battery replacement instructions.
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 installations.
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 measurementstaken on
circuits directly connected to low-voltageinstallations.
Example: power supply to domestic electrical appliances and
portable tools.
Micro-Ohmmeter Model 6255 5
www. .com [e-mail]1.800.561.8187

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®software..
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.…......................…......... Cat. #5000.60
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 Loaded …........................ 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 …............................................…......... Cat. #2129.95
RTD temperature probe with 7 ft. (2m) extension cable ............ Cat. #2129.96
Inverter – 12VDC to 120VAC 200 Watt for vehicle use ............. Cat. #2135.43
6Micro-Ohmmeter Model 6255
www. .com [e-mail]1.800.561.8187

2. FEATURES
2.1. Description
The Micro-ohmmeter Model 6255 performs low resistance measurements
from 1μΩto 2500Ω. This easy-to-use instrument measures all inductive or
non-inductive resistances with test currents (continuous 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 10ADC. Other features include long battery life and fast
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 provides 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. Enhanced 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:
 Checking metallic coating resistance, especially in aeronautics
 Ground connections and continuity measurement
 Resistance measurements on motors and transformers
 Contact resistance measurements on breakers and switches
 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
www. .com [e-mail]1.800.561.8187

2.3. Key Features
 Measures from 1µΩto 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 multiple test operation
 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 display
 Direct display of the measurement with its units, 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
8Micro-Ohmmeter Model 6255
www. .com [e-mail]1.800.561.8187

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
www. .com [e-mail]1.800.561.8187

2.5. Button Functions
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 function 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 Activates the secondary function of a button. The symbol
appears on the left side of the display.
PRINT Immediateprintingofthemeasurement to aserial printer.Ifthe
temperature compensation function has been activated, the
calculated result and the temperatures involved are also
printed.
PRINT
MEM
Retrieves stored data for printing (this function is independent
of the setting of the switch) except in the OFF and SET-UP
positions.
R ( ) Activates or deactivates the temperature compensation
function to calculate the resistance measured at a temperature
other than ambient measurement temperature.
ALARM 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).
METAL Selects the metal type for the temperature compensation
calculation: Cu, Al, or Other metal.
MEM
Stores the measurement at an address identified by an object
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.
MR
Retrieves stored data (this function is independent of the
selector setting of the switch) except for the OFF and SET-
UP positions. Data is viewed using the ▲and ►buttons.
The
R ( )
,, and ALARM buttons can be used.
Turns the display backlight ON or OFF.
Activates or deactivates the buzzer and adjusts the sound
level.
10 Micro-Ohmmeter Model 6255
www. .com [e-mail]1.800.561.8187