Draper 400 Series, DMM402 User Manual

400 SERIES

MULTIMETER

41834

IMPORTANT: Please read these instructions carefully to ensure the safe and effective use of this product and save
these instructions for future reference. This manual has been compiled by Draper Tools and is an integrated part of the
product with which it is enclosed and should be kept with it for future references.

This manual describes the purpose for which the product has been designed and contains all the necessary information
to ensure its correct and safe use. We recommend that this manual is read before any operation or, before performing
any kind of adjustment to the product and prior to any maintenance tasks. By following all the general safety
instructions contained in this manual, it will ensure both product and operator safety, together with longer life of the
product itself.

AlI photographs and drawings in this manual are supplied by Draper Tools to help illustrate the operation of the product.
Whilst every effort has been made to ensure accuracy of information contained in this manual, the Draper Tools policy

of continuous improvement determines the right to make modifications without prior warning.

1. TITLE PAGE

1.1 INTRODUCTION:

USER MANUAL FOR:

SERIES 400 MULTIMETER

Stock no. 41834.
Part no. DMM402.

1.2 REVISIONS:

Date first published January 2018

As our user manuals are continually updated, users should make sure that they use the
very latest version.

Downloads are available from: http://www.drapertools.com/manuals

DRAPER TOOLS LIMITED WEBSITE: drapertools.com
HURSLEY ROAD PRODUCT HELPLINE: [phone]
CHANDLER’S FORD GENERAL FAX: [phone]
EASTLEIGH
HAMPSHIRE
SO53 1YF
UK

1.3 UNDERSTANDING THIS MANUALS SAFETY CONTENT:

WARNING! Information that draws attention to the risk of injury or death.

CAUTION! Information that draws attention to the risk of damage to the product or

surroundings.

1.4 COPYRIGHT © NOTICE:

Copyright © Draper Tools Limited.
Permission is granted to reproduce this publication for personal & educational use only.
Commercial copying, redistribution, hiring or lending is prohibited.
No part of this publication may be stored in a retrieval system or transmitted in any other
form or means without written permission from Draper Tools Limited.

In all cases this copyright notice must remain intact.

2

2. CONTENTS

2.1 CONTENTS
Page content

1 TITLE PAGE

1.1 INTRODUCTION ............................................................................................... 2

1.2 REVISION HISTORY.......................................................................................... 2

1.3 UNDERSTANDING THIS MANUAL .................................................................. 2

1.4 COPYRIGHT NOTICE ........................................................................................ 2

2 CONTENTS

2.1 CONTENTS ........................................................................................................ 3

3 GUARANTEE

3.1 GUARANTEE...................................................................................................... 4

4 INTRODUCTION

4.1 GENERAL SPECIFICATIONS......................................................................... 5-7

4.2 HANDLING & STORAGE ................................................................................... 7

5 HEALTH & SAFETY INFORMATION

5.1 SAFETY PRECAUTIONS ................................................................................... 8

6 IDENTIFICATION

6.1 FUNCTION BUTTONS .................................................................................... 10

6.2 LCD................................................................................................................... 11

7 UNPACKING & CHECKING

7.1 PACKAGING..................................................................................................... 12

7.2 WHAT´S IN THE BOX? .................................................................................... 12

8 OPERATING INSTRUCTIONS

8.1 MANUAL RANGING AND AUTORANGING..................................................... 13

8.2 USING DISPLAY HOLD MODE AND AUTO HOLD MODE ............................. 13

8.3 MEASURING DC OR AC VOLTAGE................................................................ 14

8.4 MEASURING RESISTANCE ............................................................................ 15

8.5 CONTINUITY TEST.......................................................................................... 16

8.6 DIODE TEST .................................................................................................... 17

8.7 MEASURING INSULATION RESISTANCE...................................................... 18

8.8 AUTO POWER OFF ......................................................................................... 19

9 MAINTENANCE

9.1 BATTERY REPLACEMENT ............................................................................. 20

9.2 TEST LEADS REPLACEMENT ........................................................................ 20

10 EXPLANATION OF SYMBOLS

10.1 EXPLANATION OF SYMBOLS ........................................................................ 21

11 DISPOSAL

11.1 DISPOSAL ....................................................................................................... 22

DECLARATION OF CONFORMITY.............................................................................ENCLOSED

.............................................................................. Page

3

3. GUARANTEE

3.1 GUARANTEE

Draper tools have been carefully tested and inspected before shipment and are guaranteed to
be free from defective materials and workmanship.
Should the tool develop a fault, please return the complete tool to your nearest distributor
or contact Draper Tools Limited, Chandler's Ford, Eastleigh, Hampshire, SO53 1YF.
England.
Telephone Sales Desk: [phone] or Product Helpline [phone].
A proof of purchase must be provided with the tool.
If upon inspection it is found that the fault occurring is due to defective materials or
workmanship, repairs will be carried out free of charge. This guarantee period covering
parts/labour is 12 months from the date of purchase except where tools are hired out when
the guarantee period is 90 days from the date of purchase. This guarantee does not apply
to normal wear and tear, nor does it cover any damage caused by misuse, careless or
unsafe handling, alterations, accidents, or repairs attempted or made by any personnel
other than the authorised Draper warranty repair agent.
Note: If the tool is found not to be within the terms of warranty, repairs and carriage
charges will be quoted and made accordingly.
This guarantee applies in lieu of any other guarantee expressed or implied and variations
of its terms are not authorised.
Your Draper guarantee is not effective unless you can produce upon request a dated
receipt or invoice to verify your proof of purchase within the guarantee period.
Please note that this guarantee is an additional benefit and does not affect your statutory
rights.
Draper Tools Limited.

4. INTRODUCTION

4.1 GENERAL SPECIFICATIONS

Display: Liquid crystal display (LCD) max. reading of 3999
Negative Polarity Indication: Negative sign " - " shown on the display automatically
Sampling Rate: About 2 to 3 times/sec
Over range Indication: " OL " shown on the display
Low Battery Indication: " " shown on the display
Battery: 1.5V battery, AAA or equivalent, 6 pieces
Operating Environment: Temperature: 0°C to 40°C

Relative Humidity: < 75%
Temperature Coefficient: 0.2 x (specified accuracy)/°C (< 18°C or > 28°C)
Storage Environment: Temperature: -30°C to 60°C

Relative Humidity: < 85%
Operating Altitude: 0 to 2000 meters
Size: 190 x 89 x 62mm
Weight: About 460g (including batteries )

DC Voltage

Range Accuracy Resolution
400mV 0.1mV
4V ± (0.8% of rdg + 5 digits) 0.001V
40V 0.01V
400V 0.1V
1000V 1V

Input impedance: 10MΩ.
Max. Allowable Input Voltage: 1000V.

AC Voltage

Range Accuracy Resolution
400mV ±（1.2% rdg + 5 digits） 0.1mV
4V 0.001V
40V ±（1.0% rdg + 5 digits） 0.01V
400V 0.1V
1000V 1V

Input impedance: 10MΩ.
Frequency range: 40Hz ~ 400Hz.
Response: Average, calibrated in rms of sine wave.

Max. Allowable Input Voltage: 1000V ac rms.

5

4. INTRODUCTION

Resistance

Range Accuracy Resolution
400Ω 0.1Ω
4kΩ 0.001kΩ
40kΩ ±（1.0% rdg + 5 digits） 0.01kΩ
400kΩ 0.1kΩ
4MΩ 0.1MΩ
40MΩ ±（1.5% rdg + 10 digits） 1MΩ

Open circuit voltage: < 0.7V.

Diode and Continuity Test

Range Description Remark

Open-Circuit Voltage:

The approximate forward voltage drop

of the diode will be displayed.

The built-in buzzer will sound if the

resistance is less than about 30Ω.

The buzzer may or may not sound if

the resistance is between 30Ω and

150Ω.

The buzzer will not sound if the

resistance is more than 150Ω.

about 2.5V

Test Current:
about 0.5mA

Open-circuit voltage about

0.5V.

Overload protection：300V DC/AC rms.

6

4. INTRODUCTION

Insulation resistance

Test Voltage Display Range Resolution Test Current Accuracy

20.0 ~ 100.0MΩ 0.1MΩ

20.0 ~ 200.0MΩ 0.1MΩ

0.01 ~ 20.00MΩ 0.01MΩ
500V 20.0 ~ 200.0MΩ 0.1MΩ 0.5mA @ 500kΩΩ
200 ~ 500MΩ 1MΩ ±(5%+5)

0.01 ~ 20.00MΩ 0.01MΩ
1000V 20.0 ~ 200.0MΩ 0.1MΩ 0.5mA @ 1MΩΩ
200 ~ 2000MΩ 1MΩ ±(5%+5)

Short-Circuit Test Current (nominal): 0.5 mA
Auto Discharge: Discharge time < 1 sec for C ≤ 1μF
Minimum Measurement: 0.1MΩ

4.2 HANDLING & STORAGE

Care must still be taken when handling, dropping this machine will have an effect on the
accuracy.

The environment will have a negative result on its operation if you are not careful. If the air
is damp, components will rust. If the machine is unprotected from dust and debris;
components will become clogged.

0.01 ~ 20.00MΩ 0.01MΩ

100V

0.01 ~ 20.00MΩ 0.01MΩ

250V

0.5mA @ 100kΩΩ

0.5mA @ 250kΩΩ

±(3%+5)

±(3%+5)

±(3%+5)

±(3%+5)

7

5. HEALTH & SAFETY INFORMATION

5.1 SAFETY PRECAUTIONS

This instrument complies with IEC1010 (International Electrotechnical Commission
promulgated safety standards). Design and production using the pollution level 2 safety
requirements.

Warning

To avoid electrical shock or personal injury.

Please read the safety information and “warnings and precautions” before use.

Warning: When measuring voltage above 30V, current above 10ma, AC power with an
inductive load. Use caution not to touch exposed contacts due to the risk of electric shock,
only use approved probes or clamps.

1. Before measuring, check whether the measurement function switch is in the correct
position, check whether the test probe is connected correctly to avoid electric shock.

2. The meter is only to be used in conjunction with the supplied test leads to comply with
safety standards. If the test leads are broken or damaged, replace the test leads of the
same type or the same electrical specifications.

3. Do not use an unapproved fuse to replace the fuse inside the meter. Only replace with
the same model or the same specifications of the fuse. Before changing, remove the
test leads to ensure that there is no signal input.

4. Do not use unapproved batteries to replace the battery inside the meter. Replace only
with the same model or the same electrical specifications of the battery. Before
changing, remove the test leads to ensure that there is no signal input.

5. During electrical measurements, the body must not be directly in contact with the
earth, use insulating materials to keep your body insulated from the earth.

6. Do not store or use in high temperature, high humidity, flammable, explosive and
strong magnetic field environments.

7. Measurements exceeding the limit values of the instrument may damage the
instrument and endanger the safety of the operator.

8. Do not attempt to calibrate or service the instrument.

9. When the LCD shows “ ”, please replace the battery.

10. Do not insert the test leads to be inserted into the current terminals to measure the
voltage!

8







6. IDENTIFICATION



 LCD display window.
 Function buttons.

 Measurement function range switch.
 Probe sockets.

9

6. IDENTIFICATION

6.1 FUNCTION BUTTONS - FIG. 1

   



FIG.1



RANGE

Used to switch the meter between autorange mode and manual range mode as well as to
select desired manual range.



AUTO HOLD

Used to enter or exit Display Hold mode or Auto Hold mode.



LOCK.

To lock the reading.



TEST

To start test.



SEL

Used to switch the meter between DC voltage and AC voltage measurement functions or
between diode and continuity test functions.



" "

Press this " " button to turn on or off the back-light.



10

6. IDENTIFICATION

6.2 LCD - FIG. 2

45213

6
7

8
9

10
11

12 13 14

# Symbol Meaning

1

2

3

4

5

6

Continuity test is selected.

Diode

test is selected.

The meter is in Display Hold mode.

The meter is in Auto Hold mode.

Automatic power-off feature is enabled.

The batteries are low and must be replaced
immediately.

Analog bar-graph with scale ( available in
the insulation resistance function only).

15

10

11

12

13

14

7

8

9

High voltage is present. Be cautious!

Indicates an overrange condication in
insulation resistance measurement.

Negative sign

DC

AC

Autorange mode is selected.

Insulation resistance test is locked on.

Insulation resistance test is ongoing.

11

7. UNPACKING & CHECKING

7.1 PACKAGING

Carefully remove the product from the packaging and examine it for any sign of damage
caused during shipping. Lay the contents out and check them. If any part is damaged or
missing, do not attempt to use the tool and contact the Draper Helpline immediately (see
back page for details).

Retain the packaging material at least during the guarantee period: in case the machine
needs to be returned for repair.

Warning! Some of the packaging materials used may be harmful to children, keep them out
of reach from children.

Disposed of any packaging correctly and according to local regulations.

7.2 WHAT´S IN THE BOX?

As well as the product; there are several parts not fitted or attached to it.



 Test probe



 Test probe caps

8. OPERATING INSTRUCTIONS

8.1. MANUAL RANGING AND AUTORANGING

The meter defaults to autorange mode when switched on. When the meter is in autorange
mode, the symbol " " is displayed.

1. Press the RANGE button to enter the manual range mode, the symbol " " will

disappear.

Each subsequent press of the RANGE button increases the range.
After the highest range, the meter reverts back to the lowest range.

2. To exit the manual range mode, press and hold down the RANGE
button for approx. 2 seconds. The meter returns to the autorange
mode and " " is displayed.

8.2. USING DISPLAY HOLD MODE AND AUTO HOLD MODE

Press the button to enter the Display Hold mode. The present reading is held, and
the symbol " " appears on the display as an indication.

Press the button again to switch to the Auto Hold mode. The present reading is
held, and the symbols " " and " " appear on the display. Whenever the meter
detects a new, stable reading, it beeps and displays the new reading. If you remove the
test leads (open the input), the last held reading will be retained on the display. To exit the
Auto Hold mode and return to normal operation, press the button once more; the
symbols " " and " " will disappear.

Note: For AC or DC voltage measurements, the measured voltage must be higher than

AUTO
HOLD

AUTO
HOLD

AUTO
HOLD

0.1V, and for insulation resistance measurements, the measured resistance must be
higher than 0.1MΩ; otherwise the auto hold function may not work.

1312

8. OPERATING INSTRUCTIONS

8.3 MEASURING DC OR AC VOLTAGE

1. Connect the black test lead to the " COM " terminal and the red test lead to the " "

terminal.

2. Set the measurement function range switch to the position.

3. To select DC voltage measurement function, press the SEL button until the symbol

" " appears on the display.

To select AC voltage measurement function, press the SEL button until the symbol

" " appears on the display.

4. Connect the test leads across the source or circuit to be tested.

5. Read the reading on the display. For DC voltage measurements, the polarity of the red
test lead connection will be indicated as well.

Note:

1. To avoid electric shock to you or damage to the meter, do not apply a voltage higher
than 1000V ac or 1000V dc between the terminals.

2. In manual range mode, if " OL " is shown on the display during measurement, select
the next higher range.

14

8. OPERATING INSTRUCTIONS

8.4. MEASURING RESISTANCE

1. Connect the black test lead to the " COM " terminal and the red test lead to the

" " terminal.

2. Set the measurement function range switch to position.

3. Connect the test leads across the resistor to be tested.

4. Read the reading on the display.
Note:

1. For measurements > 1MΩ, the meter may take a few seconds to stabilize reading. This
is normal for high resistance measurements.

2. When the input is not connected, i.e. at open circuit, " OL" will be displayed as an
overrange indication.

3. Before measurement, disconnect all power to the circuit to be tested and discharged all
capacitors thoroughly.

15

8. OPERATING INSTRUCTIONS

8.5 CONTINUITY TEST

1. Connect the black test lead to the " COM " terminal and the red test lead to the

" " terminal.

2. Set the measurement function range switch to position.

3. If the symbol " " is not shown on the display, press the SEL button until the symbol

" " appears on the the display.

4. Connect the test leads across the circuit to be tested.

5. If the resistance is less than about 30Ω, the built-in buzzer will sound.

Note:
Before test, disconnect all power to the circuit to be tested and discharge all capacitors

thoroughly.

16

8.6 DIODE TEST

8. OPERATING INSTRUCTIONS

1. Connect the black test lead to the " COM " terminal and the red test lead to the
" " terminal. ( Note: The polarity of the red lead is positive " + ". )

2. Set the measurement function range switch to position.

3. If the symbol " " is not shown on the display, press the SEL button until the symbol
" " appears on the the display.

4. Connect the red test lead to the anode of the diode to be tested and the black test lead
to the cathode of the diode.

5. The display shows the approximate forward voltage drop of the diode. If the connection
is reversed, " OL " will be shown on the display.

17

8. OPERATING INSTRUCTIONS

8.7 MEASURING INSULATION RESISTANCE

IMPORTANT

Turn off all power to the circuit to be tested and discharge all

capacitors thoroughly before attempting insulation resistance test.

Warning:

1. After you set the measurement function range switch in a test voltage position

(" 100V ", " 250V ", " 500V ", or " 1000V " position) and press the TEST button, the
meter will output a high test voltage through the " INSULATION " terminals. Don't touch
any naked conductor of the meter, the test leads (including clips) and the object under
test; otherwise electric shock will occur.

2. Do not touch any object which is with charge or which may contain voltage.

3. After you finish insulation resistance test, discharge the tested object thoroughly.

4. During measurement, if the measured resistance exceeds the measuring range of the
meter, the symbol " " will appear as an indication; and if the measured resistance is
less than 0.1MΩΩ, the display will show " Lo ".

5. Before measurement, make sure that the object to be tested is without charge.

18

8. OPERATING INSTRUCTIONS

1. Connect the black test lead to a " INSULATION " terminal and the red test lead to the
other " INSULATION " terminal.

2. Set the measurement function range switch to a desired test voltage position (" 100V ",
" 250V ", " 500V ", or " 1000V " position). The display shows " - - - - ".

3. Connect the test lead probes to the circuit under test.

4. Press and hold the TEST button to start the test. The display shows the symbol " " to
remind you that high voltage is being output, and shows the symbol " "
indicating that insulation resistance measurement is being performed.

Note: If you press the LOCK button and then press the TEST button, the meter will

perform insulation resistance measurement continuously until you press the LOCK
button again.

5. Read the reading on the display.

6. Release the TEST button to stop the measurement. (If the symbols " " and
" " are being displayed, press the LOCK button to stop the measurement.)

7. After insulation resistance measurement stops, the tested object discharges through
the Meter. To avoid electric shock and personal injury, do not disconnect the test leads
from the tested object before the object is completely discharged.

8.8 AUTO POWER OFF

The display will blank and the meter will go into Sleep mode if you have not operated the
meter for about 15 minutes. While in Sleep mode, you can arouse the meter from Sleep by
pressing a button.

To disable the automatic power-off feature, hold down the SEL button while turning the
meter on.

Note:
The meter will not turn off automatically when in Display Hold mode or Auto Hold mode or

when the meter is performing insulation resistance test.

19

9. MAINTENANCE

9.1 BATTERY REPLACEMENT

Before attempting to open the battery cover or case, make sure that the test leads
have been disconnected from the meter.

1. If “ ”appears on the LCD display, it indicates that the battery should be replaced.

2. Loosen the screw fixing the battery cover and remove it.

3. Replace the used battery with a new one.

4. Refit the battery cover.

9.2 TEST LEADS REPLACEMENT

WARNING
Full in compliance with safety standards can be guaranteed only if used with test

leads supplied. If necessary, they must be replaced with the same model or same
electric ratings.

Electric ratings of the test leads: 1000V 10A.

20

10. EXPLANATION OF SYMBOLS

10.1 EXPLANATION OF SYMBOLS

WEEE
Do not dispose of Waste Electrical
& Electronic Equipment in with
domestic rubbish

Attention.

For indoor use.
Do not expose to rain.

Class II construction
(Double insulated)

Conforms to all relevant
safety standards.

Earth

Fuse

Back light

High voltage / current!
Danger.

Voltage AC

Voltage DC

Resistance in Ohms

Continuity test buzzer

Data hold / Screen lock

Warning!
Read instruction manuals before
operating and servicing this
equipment.

Diode test

Auto power off

Low battery display

214

11. DISPOSAL

11.1 DISPOSAL

- At the end of the machine’s working life, or when it can no longer be repaired, ensure
that it is disposed of according to national regulations.

- Contact your local authority for details of collection schemes in your area.

In all circumstances:

• Do not dispose of power tools with domestic waste.

• Do not incinerate.

• Do not abandon in the environment.

• Do not dispose of WEEE*

as unsorted municipal waste.

* Waste Electrical & Electronic Equipment.

22

NOTES

23

CONTACT US

Draper Tools Limited, Hursley Road,
Chandler's Ford, Eastleigh, Hampshire. SO53 1YF. U.K.

Helpline:

Sales Desk:

[phone]

[phone]

Internet: www.drapertools.com

E-mail: [e-mail]

General Enquiries: [phone]

Service/Warranty Repair Agent:
For aftersales servicing or warranty repairs, please contact the
Draper Tools Helpline for details of an agent in your local area.

YOUR DRAPER STOCKIST

©Published by Draper Tools Limited.

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means,
electronic, mechanical photocopying, recording or otherwise without prior permission in writing from Draper Tools Ltd.

DBMC0118