Chauvin Arnoux AEMC True Megohmmeter 3528 User manual

Megohmmeter
Models 6528 and 6529
ENGLISH
User Manual
www.aemc.com
True Megohmmeter®

Copyright © Chauvin Arnoux®, Inc. d.b.a. AEMC®Instruments. All rights reserved.
No part of this documentation may be reproduced in any form or by any means (including electronic
storage and retrieval or translation into any other language) without prior agreement and written consent
from Chauvin Arnoux®, Inc., as governed by United States and International copyright laws.
Chauvin Arnoux®, Inc. d.b.a. AEMC®Instruments
15 Faraday Drive • Dover, NH 03820 USA
Tel: [phone] or [phone] • Fax: [phone]
This documentation is provided “as is,” without warranty of any kind, express, implied, or otherwise.
Chauvin Arnoux®, Inc. has made every reasonable effort to ensure that this documentation is accurate;
but does not warrant the accuracy or completeness of the text, graphics, or other information contained
in this documentation. Chauvin Arnoux®, Inc. shall not be liable for any damages, special, indirect,
incidental, or inconsequential; including (but not limited to) physical, emotional or monetary damages
due to lost revenues or lost prots that may result from the use of this documentation, whether or not
the user of the documentation has been advised of the possibility of such damages.
Chauvin Arnoux®, Inc, AEMC®, and DataView® are registered trademarks of AEMC®Instruments.

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 NIST 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 #: 2126.54 / 2126.55
Model #: 6528 / 6529
Please fill in the appropriate date as indicated:
Date Received: _________________________
Date Calibration Due: ____________________
Chauvin Arnoux®, Inc.
d.b.a AEMC®Instruments
www.aemc.com

4 Megohmmeter Models 6528/6529
MEASUREMENT CATEGORIES
Thank you for purchasing the True Megohmmeter®Model 6528 or 6529. For best results
with your instrument:
■Read this user manual carefully
■Respect precautions for use
AC - Alternating current DC - Direct Current
AC or DC Double insulated
Shock Hazard Fuse
Battery Instructions that must be
read and understood
Instrument follows
recycling directives Comply with US directives
Sorting for the recycling
of electric and electronic
waste
Earth Ground
Danger Hazard
770 V
Voltage on the instrument
should not exceed 770VRMS
Definition of Measurement Categories (CAT)
■CAT IV: Test and measurement circuits connected to the source of the building’s
low-voltage network installation.
Example: Measurement on equipment installed upstream of the main fuse or
building installation cut-off switch.
■CAT III: Test and measurement circuits connected to parts of the building’s low
voltage network installation.
Example: Measurement on distribution switchboards (including secondary meters),
the circuit breakers, cabling including cables, busbars, junction boxes, circuit
breakers, power outlets in the xed installation and industrial instruments and
other equipment such as motors permanently connected to the xed installation.
■CAT II: Test and measurement circuits directly connected to points of use (power
outlets and other similar points) on the low voltage network.
Example: Measurement on circuits in network for household appliances, portable
tools and other similar instruments.

5 Megohmmeter Models 6528/6529
PRECAUTIONS FOR USE
Failure to comply with safety instructions can create a risk of electric shock, re, explosion and destruction of
the instrument or the installations. If the instrument is used other than as specied in this User Manual,
the protection provided by the instrument may be impaired.
■The operator and/or the responsible authority must carefully read and clearly understand the
various precautions to be taken in use.
■Before using the instrument, make sure it functions properly by measuring a known voltage and a
known insulation resistor, and check continuity by short circuiting both test leads.
■Do not use the instrument in an explosive atmosphere or in the presence of inammable gas or
smoke.
■Do not use the instrument on networks with a rated voltage or category higher than those listed in
this manual.
■Respect the maximum rated voltages and currents between terminals and in relation to the earth.
■Do not use the instrument if it seems damaged, incomplete, or incorrectly closed.
■Before each use, check the condition of the cable insulation, the instrument, and its accessories.
All elements on which the insulation is damaged (even partially) must be put out of service for
repair or disposed as waste.
■Use cables and accessories for voltage according to IEC 61010-031 and measurement categories
at least equal to those of the instrument. If not, an accessory of a lower category reduces the
category of the combined megohmmeter plus the accessory to that of the accessory.
■Respect the environmental conditions of use.
■Strictly comply with the fuse specications. Disconnect all cables before opening the fuse access
cover.
■Do not modify the instrument, and, do not replace components using equivalent parts. Repairs
and adjustments must be performed by qualied, approved personnel.
■Replace the battery as soon as the symbol appears on the display. Disconnect all cables
before opening the battery access cover.
■Use personal protection equipment (PPE) when conditions require it.
■Keep your hands and ngers away from the unused instrument terminals. When handling sensors
or test probes, do not place ngers beyond the physical nger guard.

TABLE OF CONTENTS
1.INTRODUCTION............................................................................................... 7
1.1 Receiving Your Shipment................................................................................................................... 7
1.2 Ordering Information .......................................................................................................................... 7
1.3 Accessories........................................................................................................................................ 8
1.4 Replacement Parts ............................................................................................................................ 8
2.OVERVIEW ...................................................................................................... 8
2.1 Description ......................................................................................................................................... 8
2.2 Insulation Resistance Testing Principal of Operation ......................................................................... 9
2.3 Megohmmeter Models 6528 & 6529 — Front View ........................................................................... 9
2.4 TEST Button and Function Keys...................................................................................................... 10
2.5 Instrument Display ........................................................................................................................... 10
2.6 Terminals...........................................................................................................................................11
2.7 Conguration Mode...........................................................................................................................11
2.8 Alarm Buzzer ................................................................................................................................... 12
2.9 Permanent Mode ............................................................................................................................. 12
2.10 Backlight (BL) ................................................................................................................................. 12
2.11 Firmware Version............................................................................................................................ 12
2.12 Alarm Functions and Indicators ...................................................................................................... 12
3.OPERATION ................................................................................................... 14
3.1 Battery Installation ........................................................................................................................... 14
3.2 Instrument Check............................................................................................................................. 14
3.3 Power Supply and Battery Life......................................................................................................... 14
3.4 Stand, Door or Magnetic Mount ....................................................................................................... 15
3.5 AC+DC or DC Voltage ..................................................................................................................... 15
3.6 Continuity ......................................................................................................................................... 16
3.7 Resistance ....................................................................................................................................... 17
3.8 Insulation Resistance Tests.............................................................................................................. 18
4. MAINTENANCE.............................................................................................. 24
4.1 Cleaning........................................................................................................................................... 24
4.2 200mA Fuse Test ............................................................................................................................. 24
4.3 Battery and Fuse Replacement ....................................................................................................... 24
5. GENERAL SPECIFICATIONS .......................................................................... 25
6. ELECTRICAL SPECIFICATIONS ..................................................................... 26
6.1 General Condition of Reference ...................................................................................................... 26
6.2 AC/DC Voltage Measurement.......................................................................................................... 26
6.3 Ground Bond Continuity Measurement............................................................................................ 26
6.4 Ground Bond Resistance Measurement.......................................................................................... 26
6.5 Insulation Resistance Specication ................................................................................................ 27
7. REPAIR AND CALIBRATION ........................................................................... 28
8. TECHNICAL AND SALES ASSISTANCE .......................................................... 28
9. LIMITED WARRANTY..................................................................................... 29

7 Megohmmeter Models 6528/6529
1.INTRODUCTION
1.1 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, le 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.
1.2 Ordering Information
Megohmmeter Model 6528 (Digital, 250V, 500V, 1kV, 420K-Ohm, V, Continuity, Alarm &
Timer).................................................................................................................................. Cat. #2126.54
Megohmmeter Model 6529 (Digital, 50V, 100V, 250V, 500V, 1kV,420k-Ohm, V, Continuity, Alarm &
Timer, PI/DAR) .................................................................................................................... Cat. #2126.55
Both models include soft carrying case, set of (2) 5 ft color-coded silicone leads, (2) color-coded
alligator clips, (2) color-coded test probes (red/black), {Rated 1000V CAT IV, UL V2}, (6) 1.5V AA batteries
and a user manual.
(1) of the following Megohmmeter Models:
Model 6528 Cat. #2126.54 or
Model 6529 Cat. #2126.55
Lead – set of (2), 5 ft silicone color-coded
(red/black) with 4mm straight/right angle
banana plugs (Rated 1000V CAT IV, UL)
Cat. #5000.94
Probe – black test probe (Rated
1000V CAT IV, 15A, UL V2)
Cat. #5000.97
Probe – red test probe (Rated
1000V CAT IV, 15A, UL V2)
Cat. #5000.98
Clip – safety alligator – black
(Rated 1000V CAT IV, 15A, UL V2)
Cat. #5000.99
Clip – safety alligator – red (Rated
1000V CAT IV, 15A, UL V2)
Cat. #5100.00
(1) Pouch – replacement for Models 1026, 6528, & 6529
(7 x 8.5 x 2”)
Cat. #2117.73
Also includes 6 AA batteries and a user manual.

8 Megohmmeter Models 6528/6529
1.3 Accessories
Continuity Probe for use with Megohmmeters and Installation
Testers .................................................................................................Cat. #2138.54
1.4 Replacement Parts
Pouch – replacement for Models 1026, 6528, & 6529 (7 x 8.5 x 2”)................................. Cat. #2117.73
Lead – set of (2), 5 ft silicone color-coded (red/black) with 4mm straight/right angle banana plugs
(Rated 1000V CAT IV, UL) .................................................................................................. Cat. #5000.94
Fuse – set of 2, FF, 200mA, 1000V, 10kA, 6x32mm .......................................................... Cat. #2971.04
Probe – black test probe (Rated 1000V CAT IV, 15A, UL V2) ............................................ Cat. #5000.97
Probe – red test probe (Rated 1000V CAT IV, 15A, UL V2) ............................................... Cat. #5000.98
Clip – safety alligator – black (Rated 1000V CAT IV, 15A, UL V2) ..................................... Cat. #5000.99
Clip – safety alligator – red (Rated 1000V CAT IV, 15A, UL V2) ......................................... Cat. #5100.00
For accessories and replacement parts, visit our store at www.aemc.com.
2.OVERVIEW
2.1 Description
The Megohmmeter Models 6528 and 6529 are portable measuring instruments with digital displays.
They are powered by batteries. These instruments can check the safety of electrical insulation. For
example, they can be used to test new insulation before they are powered up, check existing insulation
in a power-off condition, or troubleshoot potential faulty insulation.
Features include:
Model 6528 Model 6529
Insulation test voltages 250, 500, and 1000V 50, 100, 250, 500, and 1000V
Insulation Resistance  
PI and DAR ratios calculation –
Continuity measurement  
Resistance measurement  
Programmable alarms  

9 Megohmmeter Models 6528/6529
2.2 Insulation Resistance Testing Principal of Operation
Insulation resistance measurement is based on Ohm’s Law. By applying a known DC voltage and then
measuring the current owing, the instrument can determine the value of the resistance. In principle, the
value of the insulation resistance is very high, but not innite. Therefore, by measuring the low current
owing, the instrument indicates the insulation
resistance value, providing a result in kΩ, MΩ, or GΩ.
This resistance characterizes the quality of the insulation and
provides a good indication of the risks
of leakage currents.
2.3 Megohmmeter Models 6528 & 6529 — Front View
Ω
0
SET-UP
OFF
1000 V
500
V
MΩ
700 V
max
Ω
FUSED
600 V CAT IV
V
kΩ
Ω
MEGOHMMETER
250 V
MODEL 6528
HOLD
Ω
P
0
V
kΩ
GΩ
MΩ
V%
mA
AC
+
DC
HOLD
NOISE
REL
Ω
0
SET-UP
OFF
250 V
100
V
M
700 V
max
Ω
FUSED
600 V CAT IV
V
kΩ
Ω
MEGOHMMETER
50 V
MODEL 6529
500 V
1000 V
HOLD
Ω
P
0
V
kΩ
GΩ
MΩ
V%
mA
AC
+
DC
HOLD
NOISE
REL
PI
DAR
Backlit LCD
display unit
TEST button
Test Modes
Six (Model 6528)
Eight (Model 6529)
Four Function
Keys
Fused
Test Lead Terminals

10 Megohmmeter Models 6528/6529
2.4 TEST Button and Function Keys
2.4.1 TEST Button
Pressing the TEST button starts an insulation measurement. It also serves to conrm a programmed
threshold.

• Performs battery voltage check (§3.2)
• In resistance measurement, it is used to enter/exit the DMR mode and record
the reference measurement (§3.7.1)
• Starts insulation resistance test (§3.8)
2.4.2 Function Keys
KEY DESCRIPTION

HOLD
Freezes/unfreezes the measurement on the display. To unfreeze the display press
HOLD key again. In SET-UP mode, the function of the key

HOLD
is to cycle through
parameters.

Toggle between AC+DC and DC (§3.5)
Activate/deactivate audible continuity indicator (§3.6) and insulation alarm (§3.7)

Ω
0
(short press <2s) Activate/deactivate backlight (§2.10)
Ω
0
(long press >2s) Perform lead compensation for continuity checks (§3.6.1)

SET-UP
SET-UP (long >2s press): congure settings (§2.7)
(short press <2s): select type of insulation test ( , , PI, DAR (Model
6529)) (§3.8)
▲, ►Navigate the conguration menu (§2.7)
2.5 Instrument Display
1. Indicates the measurement is on hold.
2. Indicates the Differential Mode Resistance
(DMR) or relative mode function is active in
a resistance measurement.
3. Indicates the resistance of the leads is
compensated in a continuity measurement.
4. Indicates auto-off is deactivated.
5. Indicates the remaining battery life.
6. Indicates that the measurement is within
or outside of the alarm threshold set point.
7. Indicates the presence of a hazardous voltage.
8. Indicates the alarm is active in the insulation
or DMR measurement mode.
9. Indicates the audible buzzer is activated.
10. Indicates a voltage interference in a conti
nuity
or resistance measurement.
Ω
P
0
V
kΩ
GΩ
MΩ
V%
mA
AC
+
DC
HOLD
NOISE
REL
Secondary
Display
Primary
Display
6 7 8 9 10
1 2 3 4 5

11 Megohmmeter Models 6528/6529
2.6 Terminals
The instrument has two measurement terminals: + (positive) and COM (common).
2.7 Configuration Mode
Conguration mode enables you to set several options for the instrument. To open conguration
mode, turn the rotary switch to OFF. Then press and hold down the SET-UP key for >2s while
turning the rotary switch to any position. The symbol ConF appears on the LCD.
Pressing the ▲key cycles through parameters, and the ►key selects the setting for the displayed
option. Available parameters:
Insulation test mode buzzer enabled/disabled (§2.8)
1st press on ▲
P
Permanent mode enabled/disabled (§2.9)
2nd press on
▲
Backlighting enabled/disabled (§2.10)
3rd press on ▲
Firmware version number (display only, §2.11)
4th press on ▲Return to the rst screen.
Switch the instrument off by turning the rotary switch to OFF. All of your changes are applied the next
time the instrument is turned ON.
700 V
max
Ω
FUSED

SET-UP
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V
6528 rotary switch shown
>2s

12 Megohmmeter Models 6528/6529
2.8 Alarm Buzzer
To enable/disable the audible Alarm buzzer in Insulation mode:
1. Turn the rotary switch to
OFF .
2.
Press and hold down the SET-UP key for >2s turning the rotary switch to any position. The LCD
momentarily
displays ConF to indicate the insturment is in conguration mode.
3. The symbol appears on the display. If this is set to
ON , press ► to select OFF . When you
restart the instrument, the Alarm Buzzer will be disabled.
2.9 Permanent Mode
To help prolong battery life, by default the instrument’s auto-off is activated and turns off the display if
it is idle for 10 minutes. Press the TEST button to awaken the instrument.
To deactivate auto-off:
1. Turn the rotary switch to
OFF.
2. Press and hold down the SET-UP key for >2s turning the rotary switch to any position. The LCD
momentarily
displays ConF to indicate the insturment is in conguration mode.
3. Press ▲until
P
appears. If this is set to OFF , press ► to select ON .
When you restart the instrument, the auto-off is deactivated and the
P
appears on the LCD indicating
the Permanent mode is active.
2.10 Backlight (BL)
To help prolong battery life, by default the instrument’s Backlighting mode is deactivated (or auto-off of
backight is activated) and after 2 minutes the backlighting is switched off.
If you want the backlighting to stay on at all times:
1. Turn the rotary switch to
OFF .
2. Press and hold down the
SET-UP key for >2s while turning the rotary switch to any position.
The LCD momentarily displays
ConF to indicate the insturment is in conguration mode.
3. Press ▲ until appears. If this is set to
OFF , press ►to select ON . The next time the instrument
is switched on, automatic switching off of the backlighting will be deactivated and the backlighting
will stay on at all times once the key has been pushed while the instrument is actively on.
2.11 Firmware Version
To display the rmware version number currently running on the instrument:
1. Turn the rotary switch to OFF.
2. Press and hold down the SET-UP key for >2s while turning the rotary switch to any position. The
LCD will display ConF.
3. Press ▲until SOFT appears; the rmware version appears in the primary display.
2.12 Alarm Functions and Indicators

13 Megohmmeter Models 6528/6529
2.12.1 Alarm Functions
The alarm functions make it possible to rapidly conrm that the readings are OK, without looking at
the display. You can adjust the alarm function default settings by adjusting the thresholds.
There are 7 alarm thresholds:
Function Default Threshold Programmable Threshold
Insulation 50V* 50kΩ from 10kΩ to 399.9MΩ
Insulation 100V* 100kΩ from 20kΩ to 399.9MΩ
Insulation 250V 250kΩ from 50kΩ to 3.999GΩ
Insulation 500V 500kΩ from 100kΩ to 3.999GΩ
Insulation 1000V 1000kΩ from 200kΩ to 9.99GΩ
Continuity 1Ω 1Ω or 2Ω
Resistance DMR 5% from 0.1 to 3999.9%
To program a threshold, set the switch to the desired function, long press the SET-UP key for >2s
and release it when the beep sounds. The instrument displays the current threshold with the rst
digit blinking.
Use the ▲ key to set the digit and the ► key to go to the next digit. When all 4 digits have been set,
choose the unit number. Conrm by pressing the TEST button.
To enable Alarm Mode, press the Alarm Buzzer key. The symbols and are displayed.
If the measurement is below the alarm threshold, the meter emits a continous beep, the backlighting
lights red and the ×
symbol is displayed.
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V

SET-UP
kΩ

HOLD


6528 rotary switch shown
>2s
* Model 6529 only

14 Megohmmeter Models 6528/6529
3.OPERATION
3.1 Battery Installation
Place the batteries in the instrument as follows:
1. Use a Phillips screwdriver to remove the battery cover
screw on the back of the instrument (see illustration
on right).
2. Install the batteries, respecting polarity. Requires six
AA (LR6) batteries.
3. Replace the battery cover and tighten the screw.
3.2 Instrument Check
We recommend performing the following steps
when using the instrument for the rst time, or
after a long period without use.
1. Start the instrument. Ensure all display segments are displayed.
2. Perform a Continuity check (§3.6). Ensure the LCD displays >42.0Ω with no input connected.
Then short circuit both terminals, the display should show 0Ω.
3. Turn the rotary switch to V, check a known voltage (e.g., a battery) and ensure that the
measured
voltage is correct.
4. Disconnect from the voltage source, and press the TEST button. The instrument’s battery voltage
is displayed. Ensure this is above 6.6V.
5. Turn the rotary switch to an insulation voltage setting (§3.7), and check a known resistor that
is within the
measurement range for the test voltage selected.
6. When all the steps above produce expected results, you can start using the instrument.
3.3 Power Supply and Battery Life
The power supply is six 1.5V alkaline batteries (type AA or LR6). Nominal voltage is 6.6 to 9.6V. Below
6.6V the instrument will not turn on.
■Battery life for insulation measurements: Average battery life for insulation measurement
(according to IEC61557-2 clause 6.7) is 2000 measurements with new batteries at room
temperature (5s ON, 25s OFF).
■Battery life for voltage and resistance measurements: Average battery life for voltage
and resistance with new batteries at room temperature @ 400kΩ is > 300h.
■Battery life for continuity checking: Average battery life for continuity checking (according
to IEC 61557-4 clause 6.6) is > 6000 measurements with new batteries at room temperature
(5s ON, 25s OFF). For shorter continuity tests (0.8s ON, 10s OFF) battery life is > 40,000 tests.
■Battery voltage: To check the battery voltage, press and hold the TEST button with the switch
set to the Vposition.

15 Megohmmeter Models 6528/6529
3.4 Stand, Door or Magnetic Mount
For convenience, the instrument can be used in
different positions:
■With the stand - simply pull the back stand
down to free it from its slot, then fold it and
insert the end in the upper available slot.
■The stand can be placed on the top of a
door or other similar surface by positioning
the stand over the top edge as shown.
■The stand is equipped with magnets
allowing the instrument to be attached
to a metal surface.
3.5 AC+DC or DC Voltage
The instrument measures AC+DC or DC voltage, to minimize risk when measuring an
unknown voltage. Measure AC+DC voltage rst. Be sure to respect the rated voltage
and category.
If the measurement departs from the measurement range, the instrument displays OL.
1. Turn the rotary switch to the V position.
2. Toggle between AC+DC or DC voltage measurement
by pressing the key.
3. Connect the red test lead to the +terminal and the
black test lead to the COM terminal.
4. Measure the voltage by attaching the test leads to the
desired test points of the circuit.
Note: When the rotary switch is set to V, you can
display the instrument’s battery voltage by pressing and
holding down the TEST key with no voltage present
on the test leads. Releasing the key returns to voltage
measurement mode.
V
AC
+
DC VDC

Toggle
between
AC + DC
and DC

16 Megohmmeter Models 6528/6529
3.5.1 Voltage Error Indicators
■If the measurement is outside of the measurement range, the instrument displays OL.
3.6 Continuity
To avoid electrical shock and damage to the instrument when measuring resistance or continuity
in a circuit, ensure power to the circuit is turned OFF and all capacitors are discharged.
The measurement can be a󰀨ected by (1) impedances of additional operating circuits connected in
parallel, or (2) transient currents.
In Continuity mode the instrument outputs a current above 200mA @ 2Ω between the +and COM
terminals. The voltage across the circuit under test is measured by the instrument; this voltage is then
used to calculate resistance (R = V/I).
1. Turn the rotary switch to Ω.
2. The continuity threshold can be either 1Ω or 2Ω. To change this, press SET-UP for >2s. This
displays the threshold setting. Press ▲to change this, then press TEST to exit SET-UP mode.
3. Connect the red test lead to the +terminal and the black test lead to the COM terminal.
4. To compensate leads see §3.6.1.
5. Check continuity by connecting the leads to the desired point of the circuit. If resistance is under
the threshold, the buzzer will sound, and will display on the LCD designating a short circuit. If
the resistance is above the threshold, the backlight will light up red, the buzzer won’t sound, and the
LCD displays ×. The LCD displays the measured continuity on its primary display and test current
on the secondary display (§2.5). To activate the audible alarm signal, press the key. The
symbol is displayed
and a beep is emitted when the measurement is below the threshold. This
lets you check that the continuity
measurement is OK just by listening, without looking at the display.
If you change the leads without redoing the compensation, the reading can become negative.
Ω
%
REL
Secondary Display
Primary Display
Ω
%
REL

17 Megohmmeter Models 6528/6529
3.6.1 Compensation of the Measurement Leads
Short the input terminals by touching them together. Then press the
Ω
0
key and hold it down for >2s.
The LCD should display 0Ω. If current is 0 mA when the terminals are shorted, verify the fuse is good.
NOTE: If the resistance of the leads is >5Ω, compensation is not possible.
To remove test lead compensation, press
Ω
0
for >2s with the test leads open. The buzzer can be
disabled by pressing the alarm key.
3.6.2 Continuity Alarm Indicators
■The alarm is always active in continuity measurement.
■The instrument gives you a choice of two alarm thresholds: 1Ω or 2Ω.
■If the measurement is below the threshold, the symbol is displayed.
■If the measurement exceeds the threshold, the backlighting lights turn red and the ×symbol
is displayed.
3.6.3 Continuity Error Indicators
■If the measurement is beyond the measurement range, the instrument displays >42.00Ω.
■If during the measurement the symbol appears on the LCD, transient currents are
affecting the measurement. Ensure the circuit under measurement is de-energized.
■When the measurement current is <200mA, the measurement is still correct but is no longer
compliant with the IEC standard continuity measurements.
■The instrument displays the AC+DC voltage. If it is >30V, the symbol is displayed to warn
the user that the voltage on the terminals is hazardous and the instrument emits a pulsed beep.
■If there is a voltage of more than 0.4V on the object to be tested, the instrument displays .
3.7 Resistance
To perform a resistance test, the instrument outputs a DC voltage and measures the current across
the circuit under test. The instrument then calculates the resistance.
To avoid electrical shock and damage to the instrument when measuring resistance or continuity in
a circuit, ensure power to the circuit is turned OFF and all capacitors are discharged.
3.7.1 Differential Mode Resistance (DRM) Mode
In the resistance measurement mode, there is a very useful feature
called the Differential Resistance Mode (DRM). It can be used as
an incoming inspection tool, a radiant heat element qualifying tool
or a quality check on production lines to name a few.
This is a valuable feature to compare successive measurements to
a previously measured
“reference” resistance. If the measurement
falls outside a congured threshold percentage
, a visual and audible
alarm will occur.
Start by setting the threshold in %
1. Turn the rotary switch to the kΩ position.
2. Press and hold the SET-UP key for >2s. The threshold
percentage appears in the LCD secondary display area, with
the rst digit blinking.
3. You can adjust the percentage by pressing the ▲to increment
the blinking digit and the ►to advance to the next digit. 6528 rotary switch shown
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V

18 Megohmmeter Models 6528/6529
4. The threshold percentage can be set from 0.1% to
399.9%; default is 5%. When nished setting the threshold
percentage, press TEST to exit SET-UP mode.
5. Connect the red lead to the +terminal and the black lead
to the COM terminal.
6. Connect the test leads to the device to be used as the reference
resistance. The resistance measurement will appear in
the
primary display area.
7. Press the TEST button to accept that as the reference
value. The ΔRel symbol will appear and the percentage
difference will appear on the top line of the secondary
display indicating the instrument is in DRM mode.
As you take subsequent measurements, the difference between
the measurement and the reference is displayed both in ohms
(primary display (§2.5)) and as a percentage (secondary
display (§2.5)).
If the difference exceeds the threshold percentage, an alarm
activates with a red back lit display and an audible buzzer (if
enabled) indicating the out of tolerance condition.
3.7.2 Resistance Mode Alarm Indicators
■Before starting an insulation measurement, pressing
the key activates the alarm. The alarm threshold
is displayed, along with the and symbols.
■If the measurement exceeds the threshold, the 
symbol is displayed.
■If the measurement is below the threshold, the
instrument emits a continuous beep, the backlight
turns red and the ×symbol is displayed.
3.7.3 Resistance Mode Error Indicators
■If there is a voltage of more than 0.4V on the object to be tested, the instrument displays .
■If the object to be tested is at a hazardous voltage, >30V, the symbol is displayed and the
instrument emits a pulsed beep.
■If the measurement is outside of the measurement range, the instrument displays >420.0kΩ.
3.8 Insulation Resistance Tests
To avoid electrical shock and damage to the instrument when measuring resistance or continuity
in a circuit, ensure power to the circuit is turned OFF and all capacitors are discharged.
In Insulation Resistance mode the instrument outputs a DC voltage. This voltage depends on the
resistance to be measured. The device measures the voltage and current present between the two
terminals and determines the value of R=V/I.
You can perform up to ve types of resistance tests, depending on instrument model. By default, the
instrument is in “unlocked” untimed test mode. In this mode, the test begins when you press the
TEST button, and ends when you release it. This mode is typically used to run short “spot” tests.
%
Ω
M
Ω
%
REL
DRM
Mode
Ω
%
REL

19 Megohmmeter Models 6528/6529
The other test types are selected via the SET-UP key:
KEY DESCRIPTION
1st press
Lock the TEST button. In this mode, after you start the measurement, it
continues without requiring you to keep the TEST button pressed. The test will
run until you stop it, or when 40 minutes have passed.
2nd press
Activate timed test mode. You can set the test duration between 1 second and
39:59 minutes.
3rd press
Exit
PI
Exit timed text mode (Model 6528).
Enable the PI function (Model 6529). This is used to calculate the polarization
index (the ratio of the measurement at T2 [default 10 minutes] to the measurement
at T1 [default 1 minute]).
KEY DESCRIPTION
4th press DAR Enable the DAR function (Model 6529). This is used to calculate the dielectric
absorption ratio (the ratio of the measurement at T2 [default 1 minute] to the
measurement at T1 [default 30 seconds]).
5th press TEST Exit timed test mode (Model 6529).
3.8.1 Untimed Test (Including Unlocked and Locked)
1. Turn the rotary switch to an insulation voltage setting, Choices are 250 V, 500 V, 1000 V (available
on both the Models 6528 and 6529), and 50 V and 100 V (available on Model 6529 only). The test
voltage to select depends on the operating voltage of the device to be tested.
2. To run an unlocked test, skip this step and continue with step 3. To lock the TEST button, press the
SET-UP key once. The icon appears on the LCD.
3. To set an Alarm (§2.12).
4. Use the leads to connect the system to be tested to the instrument’s terminals. The test sample
must be powered down and discharged. When testing insulation, the typical connection is negative
(black) lead to conductor and positive (red) lead to ground or the outer insulation of the test sample.
5. Press the TEST button to start the test.
If you are running an unlocked test, hold down the TEST button until the displayed measurement
is stable.
If you are running a test, release the TEST button.
Note that if the instrument detects a voltage greater than 30V in the system under test, pressing the
TEST button has no effect because the test will be prohibited.
When the insulation measurement stabilizes, it appears on the primary display (§2.5). The secondary
display (§2.5) shows the test voltage.
MΩ
V
OFF
1000 V
500
V
MΩ
V
kΩ
Ω
250 V

6528 rotary switch shown

20 Megohmmeter Models 6528/6529
6. When performing insulation measurement, you can press the key to enable the alarm
feature. If the
measurement falls below the alarm threshold, the alarm will activate. To set alarm
threshold (§2.12).
7. At the end of the test, either release the TEST button (for unlocked tests) or press the TEST button
a second time (for tests). The instrument stops generating the test voltage and discharges
the device being tested. During this process the discharging voltage value is displayed to indicate
residual voltage. The measured value will remain on the display until you make another
measurement,
press the HOLD key, or turn OFF the instrument. You can also start another measurement
immediately by a long press on the TEST button.
Do not disconnect the instrument while the symbol is still displayed.
3.8.2 Timed Test (Including PI and DAR)
Both the Model 6528 and Model 6529 can perform timed tests that stop automatically after a dened
duration. In addition, the Model 6529 can perform polarization index (PI) and dielectric absorption
ratio (DAR) tests.
Polarization index is a useful indicator of motor insulation health. It can identify the accumulation of
contaminants as well as any physical damage to the insulation itself. The test involves applying
a
positive charge to a motor’s conductors and a negative charge to the motor frame therefore
polarizing
the insulation. This test essentially measures the change over time. Healthy clean insulation
will charge over time resulting in the decrease of induced current and an increase in insulation
resistance.
Unhealthy insulation will result in a at to decreasing insulation resistance over time.
The PI test compares the measurement of insulation resistance at two points in time. The most prominent
used time points are at 1 and 10 minutes. Model 6529 defaults to these two test points labeled as T1
and T2. The instrument allows user programming of both time points if necessary. Acceptable values
can be programmed between 1 second and 30 minutes for each test point. The time for T2 must be at
least 1 second longer than T1.
The polarization index is calculated by dividing the insulation resistance value at point in time T2 (e.g.,
10-min) by the insulation resistance value taken at point in time T1 (e.g., 1-min).
Ω
0
SET-UP
OFF
1000 V
500
V
MΩ
700 V
max
Ω
FUSED
600 V CAT IV
V
kΩ
Ω
MEGOHMMETER
250 V
MODEL 6528
HOLD
P
MΩ
V
Press TEST to start
measurement
Timer
Model 6528 shown