Draper 300 Series User manual

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.
300 SERIES
MULTIMETER
41822

2
1.1 INTRODUCTION:
USER MANUAL FOR:
SERIES 300 MULTIMETER
Stock no. 41822.
Part no. DMM301.
1.2 REVISIONS:
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.
Date first published August 2017
1. TITLE PAGE

3
2.1 CONTENTS
Page content .............................................................................. Page
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 ......................................................................... 5-9
4.2 HANDLING & STORAGE.................................................................................. 10
5 HEALTH & SAFETY INFORMATION
5.1 SAFETY PRECAUTIONS ................................................................................. 11
6 IDENTIFICATION......................................................................................................12-13
7 UNPACKING & CHECKING
7.1 PACKAGING..................................................................................................... 14
7.2 WHAT´S IN THE BOX?..................................................................................... 14
8 OPERATING INSTRUCTIONS
8.1 USING RELATIVE MODE................................................................................. 15
8.2 MANUAL RANGING AND AUTORANGING ..................................................... 15
8.3 DATA HOLD MODE.......................................................................................... 15
8.4 TRIGGER + - SELECTION ............................................................................... 15
8.5 MEASURING DC OR AC VOLTAGE................................................................ 16
8.6 MEASURING DC OR AC CURRENT ............................................................... 16
8.7 MEASURING RESISTANCE (Ω) ...................................................................... 17
8.8 CONTINUITY TEST .......................................................................................... 17
8.9 MEASURING FREQUENCY............................................................................. 17
8.10 MEASURING DUTY CYCLE ............................................................................ 18
8.11 MEASURING CAPACITANCE.......................................................................... 18
8.12 DIODE TEST..................................................................................................... 18
8.13 MEASURING TEMPERATURE ........................................................................ 19
8.14 MEASURING RPM ........................................................................................... 19
8.15 MEASURING DWELL ANGLE.......................................................................... 20
8.16 MEASURING PULSE WIDTH........................................................................... 20
8.17 AUTO POWER OFF ......................................................................................... 20
9 MAINTENANCE
9.1 BATTERY REPLACEMENT.............................................................................. 21
10 EXPLANATION OF SYMBOLS
10.1 FUNCTION KEYS EXPLAINED........................................................................ 22
10.2 EXPLANATION OF SYMBOLS......................................................................... 23
11 DISPOSAL
11.1 DISPOSAL ....................................................................................................... 24
DECLARATION OF CONFORMITY............................................................................ ENCLOSED
2. CONTENTS

4
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.
3. GUARANTEE

5
DC Voltage
Range Accuracy Resolution
6V ± (0.8% of rdg + 5 digits) 0.001V
60V 0.01V
600V ± (1.0% of rdg + 5 digits) 0.1V
Input Impedance: About 10MΩ
Overload Protection: 600V DC/AC rms.
4.1 GENERAL SPECIFICATIONS
Fuse Protection for " VΩmAHz " Terminal Inputs: 600mA, 600V,
FAST, Min. Interrupt Rating 10000A.
Fuse Protection for " 10A " Terminal Inputs: 10A, 600V, FAST,
Min. Interrupt Rating 10000A.
Display: 3 5/6-digit display, with a max. reading of 5999.
Over range Indication: " OL " shown on the screen.
Negative Polarity Indication: Negative sign " -" shown on the
screen automatically.
Sampling Rate: About 2 to 3 times/sec.
Operating Temperature: 0°C to 40°C< 75%RH.
Temperature Coefficient: 0.2 x (specified accuracy)/°C ( < 18°C
or > 28°C).
Storage Temperature: -10°C to 50°C< 85%RH.
Operating Altitude: 0 to 2000 meters.
Battery: 9V battery, 6F22 or equivalent, 1 piece.
Low Battery Indication: " " shown on the display.
Dimensions: 150 X 73 X 47mm.
Weight: About 228g ( including battery and holster ).
4. INTRODUCTION

6
AC Voltage
Range Accuracy Resolution
6V ±（1.0% rdg + 5 digits）0.001V
60V 0.01V
600V ±（1.2% rdg + 5 digits）0.1V
DC Current
Range Accuracy Resolution
60mA ±（1.0% rdg + 7 digits）0.01mA
600mA 0.1mA
6A ±（1.5% rdg + 7 digits）1mA
10A 10mA
AC Current
Range Accuracy Resolution
60mA ±（1.8% rdg + 10 digits）0.01mA
600mA 0.1mA
6A ±（2.5% rdg + 10 digits）1mA
10A 10mA
- Input Impedance: About 10MΩ
- Overload Protection: 600V DC/AC rms.
- Frequency Range: 40 to 400Hz
- Response: Average, calibrated in rms of sine wave
- Overload Protection:
Protection for "VΩmAHz" terminal inputs: Fuse, 600mA/600V, Fast.
Protection for " 10A " terminal inputs: Fuse, 10A/600V, Fast
- Max. Input Current:10A ( For measurements > 2A: measurement duration < 10 secs, and
interval > 15 minutes )
- Overload Protection:
Protection for "VΩmAHz" terminal inputs: Fuse, 600mA/600V, Fast
Protection for "10A" terminal inputs: Fuse, 10A/600V, Fast
- Max. Allowable Input Current: 10A ( For measurements > 2A: measurement duration
<10 secs, and interval > 15 minutes )
- Frequency Range: 40Hz ~ 400Hz
- Response: Average, calibrated in rms of sine wave
4. INTRODUCTION

7
- Open Circuit Voltage: <0.7V
- Open circuit voltage: approx. 0.7V
Resistance
Range Accuracy Resolution
600Ω±（1.0% rdg + 5 digits）0.1Ω
6kΩ0.001kΩ
60kΩ0.01kΩ
600kΩ0.1kΩ
6MΩ±（1.5% rdg + 5 digits）0.001MΩ
60MΩ±（3.0% rdg + 10 digits）0.01MΩ
Capacitance ( use Relative mode )
Range Accuracy Resolution
40nF ±（3.5% rdg + 20 digits）0.01nF
400nF ±（2.5% rdg + 5 digits）0.1nF
4μF ±（3.5% rdg + 5 digits）0.00μF
40μF ±（4.0% rdg + 5 digits）0.01μF
400μF ±（5.0% rdg + 5 digits）0.1μF
4000μF not specified 1μF
Continuity Test
Range Function
The built-in buzzer will sound if the resistance is less than about 20Ω.
The buzzer may or may not sound if the resistance is between
20Ωand 150Ω.
The buzzer will not sound if the resistance is more than 150Ω.
Diode
Range Resolution Function
The approx. forward
voltage drop of the diode will be
displayed.
Open Circuit Voltage: about 3V
Test Current: about 0.8mA
4. INTRODUCTION

8
- Input voltage: 1V rms ~ 20V rms.
Frequency
Range Accuracy Resolution
9.999Hz 0.001Hz
99.99Hz 0.01Hz
999.9Hz ±（1.0% rdg + 5 digits）0.1Hz
9.999kHz 1Hz
99.99kHz 10Hz
999.9kHz 100Hz
9.999MHz not specified 1kHz
- Input Voltage: 2Vp 〜50Vp
- Frequency Range: 4Hz 〜1kHz
Duty Cycle
Range Accuracy Resolution
0.5% ~ 99.9% ±（2.0% rdg + 7 digits）0.1%
Pulse Width
Range Accuracy Resolution
0.5 ~ 20ms ±（2.0% rdg + 3 digits）0.1ms
- Input Voltage: 2Vp 〜50Vp
4. INTRODUCTION
Note:
1. Use K type thermocouple.
2. Accuracy does not include error of the thermocouple probe.
3. Accuracy specification assumes ambient temperature is stable to ±1℃. For ambient
temperature changes of ±5℃, rated accuracy applies after 1 hour.
Temperature
Range Accuracy Resolution
-20°C ~ 0°C ±（6.0% + 5°C）0.1°C
°C 0°C ~ 400°C ±（1.5% + 4°C）0.1°C
400°C ~ 1000°C ±（1.8% + 5°C）1°C
-4°F ~ 32°F ±（6.0% + 9°F）0.1°F
°F 32°F - 752°F ±（1.5% + 7.2°F）0.1°F
752°F ~ 1832°F ±（1.8% + 9°F）1°F

9
- Input Voltage: 2Vp 〜50Vp
- Max. Allowable RPM of Engine: 20000RPM
Tach ( rotation speed )
Range Accuracy Resolution
2-stroke engine:
60 〜20000RPM ±（0.5% rdg + 3 digits） <10000RPM: 1RPM
4-stroke engine: ≥10000RPM: 0.1kRPM
120 〜20000RPM
- Input Voltage: 2Vp 〜50Vp
- Max. Allowable RPM of Engine: 20000RPM
Dwell Angle
Number of Cylinders Range Resolution Accuracy
4 cylinders 0 ~ 90º 0.1º ±（2.5% rdg + 2 digits）
5 cylinders 0 ~ 72º
6 cylinders 0 ~ 60º
8 cylinders 0 ~ 45º
4. INTRODUCTION
- Overload Protection: 250V DC or rms AC
Engine Dwell
Range Accuracy Resolution
4CYL ±（3º ) 0.1º
6CYL ±（3º ) 0.1º
8CYL ±（3º ) 0.1º

10
4.3 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.
4. INTRODUCTION

11
5.1 SAFETY PRECAUTIONS
Warning
To avoid electrical shock or personal injury.
Please read the safety information and “warnings and precautions” before use.
This instrument complies with IEC1010 (International Electrotechnical Commission
promulgated safety standards). Design and production using the pollution level 2 safety
requirements.
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!
5. HEALTH & SAFETY INFORMATION

12
 LCD display window.
 Switch between functions.
 Range switch button.
 Measurement function range switch.
 Probe sockets.
 Relative mode.
 Hold button.

6. IDENTIFICATION


 
 

13
6. IDENTIFICATION
4-stroke engine
measurement is selected.
2-stroke engine
measurement is selected.

Positive (+) trigger is selected.
Negative (-) trigger is selected.

Cylinder number display which
shows the presently selected
engine cylinder number.

The battery is low and
must be replaced immediately.

Diode test is selected.

Continuity test is selected.

Relative mode is active.

Automatic power-off feature
is enabled.

Data Hold is enabled.

Dwell angle measurement
is selected.

DC

Negative sign

AC

Autorange mode is active.


14
7.2 WHAT´S IN THE BOX?
As well as the product; there are several parts not fitted or attached to it.
 Test probe caps
 Test probe
 Temperature probe
 Inductive pick up
   
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. UNPACKING & CHECKING

15
8.2 MANUAL RANGING AND AUTORANGING
The meter defaults to autorange mode in measurement functions which have both
autorange mode and manual range mode. When the meter is in autorange mode,
" AUTO " is displayed.
1. Press the " RANGE " button. The meter enters the manual range mode, and " AUTO "
turns off. Each subsequent press of the " RANGE " button increases the range. After
the highest range, the meter returns to the lowest range.
2. To exit the manual range mode, press and hold down the " RANGE " button for
about 2 seconds. The meter returns to the autorange mode.
8. OPERATING INSTRUCTIONS
8.1 USING RELATIVE MODE
Selecting Relative mode causes the meter to store the present
reading on the screen as a reference for subsequent measurements.
1. Press the " REL " button. The meter enters the Relative mode and stores the present
reading on the screen as a reference for subsequent measurements, and " "
appears on the screen as an indicator. The screen reads zero.
2. When you perform a new measurement, the screen will show the difference between
the reference and the new measurement.
3. Press the " REL " button again, the meter will exit the Relative mode and the
symbol " " will disappear.
Note:
1. When in Relative mode, the actual value of the object under test must not exceed the
full-scale reading of the selected range. Use a higher range if necessary.
2. Relative mode is available only for voltage, current, resistance, capacitance, and
temperature measurements.
p
"
8.3 DATA HOLD MODE
Press the " HOLD " button briefly to freeze the reading on the screen, " " will appear on
the screen as an indicator. To exit Data Hold mode, press briefly this button again " "
disappears.
8.4 TRIGGER + - SELECTION
Trigger + or - is to identify whether the on or off portion of the signal under test is of
measuring interest. For example, as for a periodic square wave waveform whose period is
10ms, if you get a pulse width reading of 2ms in the trigger + (on portion), you then will get
a pulse width reading of 8ms (10ms - 2ms ) in trigger - (off portion).
To toggle between trigger + and -, press the " SEL " button.
Note：Trigger + - selection is available only for pulse width measurement functions.

16
8.5 MEASURING DC OR AC VOLTAGE
1. Connect the black test lead to the " COM " terminal and the red test lead to the
" VΩmAHz " terminal.
2. Set the measurement function range switch to the position. Then press the " SEL "
button to select DC or AC voltage measurement, the screen will show the
corresponding symbol.
3. Connect the test leads across the source or circuit to be tested.
4. Read the reading on the screen. For DC voltage measurements, the polarity of the red
lead connection will be indicated as well.
Note:
To avoid electric shock to you or damages to the meter, do not apply a voltage higher than
600V DC or AC between the terminals.
8. OPERATING INSTRUCTIONS
8.6 MEASURING DC OR AC CURRENT
1. Connect the black test lead to the " COM " terminal. If the current to be measured is
less than 600mA, connect the red test lead to the " VΩmAHz " terminal. If the current is
between 600mA and 20A, connect the red test lead to the " 10A " terminal instead.
2. Set the measurement function range switch to or range position.
Note: If the red test lead is connected to the " VΩmAHz " terminal, the function switch
must be set to the position. If the red test lead is connected to the " 10A "
terminal, the function switch must be set to the position.
3. Press the " SEL " button to select DC or AC current measurement, the screen will show
the corresponding symbol.
4. Turn off power to the circuit to be measured, and then discharge all capacitors.
5. Break the circuit path to be measured, and connect the test leads in series with the
circuit.
6. Turn on power to the circuit, then read the reading on the screen.
For DC current measurements, the polarity of the red lead connection will be indicated
as well.
Note:
If you don't know the magnitude of the current to be measured beforehand, select the
highest range first and then reduce it range by range until satisfactory resolution is
obtained.

17
8.8 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. Then press the " SEL "
button until the symbol " " appears on the screen.
3. Connect the test leads across the circuit to be tested.
4. If the resistance is less than about 20Ω, the built-in buzzer will sound.
Note:
Before test, disconnect all power to the circuit to be tested and
discharged all capacitors thoroughly.
8.9 MEASURING FREQUENCY
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 Hz % position. Then press the " SEL "
button until " Hz " appears on the screen.
3. Connect the test leads across the source or circuit to be tested.
4. Read the reading on the screen.
Note:
1. For frequency measurements, the range exchange is automatic, and the measurement
range is: 0MHz - 10MHz.
2. The voltage of input signal should be between 1V rms and 20V rms. The higher the
frequency, the higher the required input voltage.
3. For measurements < 10Hz, the amplitude of input signal must be more than 2V rms.
8. OPERATING INSTRUCTIONS
8.7 MEASURING RESISTANCE (Ω)
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. Then press the " SEL "
button to select resistance function ( the symbols " " and " " capacitance
measurement unit do not appear on the screen ).
3. Connect the test leads across the object to be tested.
4. Read the reading on the screen.
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 over
range indication.
3. Before measurement, disconnect all power to the circuit to be measured and
discharged all capacitors thoroughly.
VΩmAHz
VΩmAHz
VΩmAHz

18
8. OPERATING INSTRUCTIONS
8.10 MEASURING DUTY CYCLE
1. Connect the black test lead to the " COM " terminal and the red test lead to the
" VΩmAHz " terminal.
2. Set the measurement function range switch to Hz % position. Then press the " SEL "
button until " %" appears on the display.
3. Connect the test leads across the signal source to be measured.
4. Read the reading on the display.
Note:
After you remove the measured signal, its reading may still remain on the screen. Pressing
the " SEL " button twice will zero the display.
8.12 DIODE TEST
1. Connect the black test lead to the " COM " terminal and the red test lead to the
" VΩmAHz " terminal. ( Note: The polarity of the red lead is positive " + ". )
2. Set the measurement function range switch to position. Then press the " SEL "
button until the symbol " " appears on the display.
3. 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.
4. The screen shows the approximate forward voltage drop of the diode. If the connection
is reversed, " OL " will be shown instead.
8.11 MEASURING CAPACITANCE
1. Set the measurement function range switch to position. Then press the " SEL "
button until the screen shows unit of capacitance.
2. Connect the Adapter to the " COM " and " VΩmAHz " terminals as shown in the figure.
3. If the screen shows a reading other than zero, press the " REL " button to zero the
screen; the meter will enter Relative mode.
4. Make sure that the capacitor to be measured has been discharged thoroughly, and
then insert the two leads of the capacitor into the two holes of the Adapter. ( Ensure
correct polarity connection when measuring electrolytic capacitor. )
5. Wait until the reading is stable, then read the screen.
( For high-capacity capacitors, it may take about 30 seconds for reading to stabilize. )

19
8. OPERATING INSTRUCTIONS
8.13 MEASURING TEMPERATURE
1. Set the measurement function range switch to °C °F position. Then press the " SEL "
button to select between °C and °F.
2. Connect the negative " –" plug of the K type thermocouple to the " COM " terminal and
the positive " +" plug of the K type thermocouple to the " VΩmAHz " terminal.
3. Connect the sensing end of the thermocouple to the object to be measured.
4. Wait until the reading is stable, then read the screen.
Note:
1. When the measured temperature exceeds 1000°C /1832°F, the screen will show
" OL ".
2. To avoid possible damage to the meter or other equipment, remember that while the
meter is rated for -20°C to +1000°C and -4°F to 1832°F, the K Type Thermocouple
provided with the meter is rated to 250°C. For temperatures out of that range, use a
higher rated thermocouple.
The K Type Thermocouple provided with the meter is a present, it is not professional
and can only be used for non-critical reference measurements. For accurate
measurements, use a professional thermocouple.
8.14 MEASURING RPM
1. Set the measurement function range switch to position.
2. If the engine to be tested is a 2-stroke engine, press the " SEL " button until the symbol
" " appears on the upper area of the screen.
If the engine to be tested is a 4-stroke engine, press the " SEL " button until the symbol
" " appears on the upper area of the screen.
3. Connect the negative (black) output plug of the inductive pick up to the " COM "
terminal and the positive (red) output plug of the inductive pick up to the " VΩmAHz "
terminal.
4. Clamp the inductive pick up to a spark plug wire with the arrow mark on the inductive
pick up pointing to the spark plug. Make sure that the pick up jaws are completely
closed.
5. Start the engine and read the reading on the screen.
Note：
1. The input voltage must be between 2Vp and 50Vp. If the voltage is too low, it will be
impossible to make measurement.
2. If the engine's rotation speed is too low, the stability of reading will decrease.
3. The polarity of the input voltage must be correct; otherwise it will be impossible to
make measurement.
4. The inductive pick up will become hot and the reading will become unstable after the
measurement lasts for a period of time; in this condition, remove the inductive pick up
from the spark plug wire to stop the measurement and wait until the inductive pick up
cools down, then you can resume the measurement.

20
8. OPERATING INSTRUCTIONS
8.15 MEASURING DWELL ANGLE
1. Connect the black test lead to the " COM " terminal and the red test lead to the
" VΩmAHz " terminal.
2. Set the measurement function range switch to position. Then press the " SEL "
button until the displayed number ( 4, 5, 6 or 8) of cylinders matches the engine under
test.
3. Connect the black test lead to chassis or the negative terminal of the vehicle battery,
and connect the red test lead to the low voltage terminal of the distributor or the
negative terminal of the ignition coil.
4. Start the engine and read the reading on the display.
Note：
1. The input voltage must be between 2Vp and 50Vp. If the voltage is too low, it will be
impossible to make measurement.
2. Reading's stability will decrease if the rotation speed of the engine is too low.
3. The polarity of the input voltage must be correct; otherwise it will be impossible to make
measurement.
8.16 MEASURING PULSE WIDTH
1. Connect the black test lead to the " COM " terminal and the red test lead to the
" VΩmAHz " terminal.
2. Set the measurement function range switch to position.
3. Press the " SEL " button to select positive (+) trigger or negative (-) trigger, the screen
will show the corresponding symbol.
4. Connect the test leads as shown in the figure. Then read the reading on the screen.
8.17 AUTO POWER OFF
1. After fifteen minutes without any operation the meter will automatically switch off.
2. To disable auto power off, press and hold down any button while rotating the rotary
switch from " OFF " position to other switch position.