Mastech MS2128A User manual

MS2128A
DIGITAL CLAMP METER
OPERATION MANUAL
CAT III
600V
40 0A
REL

1.1 Preliminary
1.2 During use
1.3 Symbols............
CONTENTS CONTENTS
1. Safety Information ...............................1
............................................1
...................................2
.............................3
4
............7
...................7
..........................15
.................................15
.......................................15
................16
....................................16
....................................3
..............................17
....
..
1.4 Maintenance............
2. Description...........................................
2.1 Names OF Parts ...................................5
2.2 Switch, Buttons And Input Jacks
2.3
3. Specifications ......................................9
4. Operation Instruction
...........................9
3.1 General Specifications
3.2 Technical Specifications.........................9
4.1 Holding Readings
4.2 Switching Rel
4.3 Switching Frequency Or Duty
4.4 Switching Maximum Or
Minimum Value
4.5 Switching Functions
4.6 Back Light And Clamp Lighting Bulb
4.7 Auto Power Off..........................................18
4.8 Preparing For Measurement
4.9 Measuring Ac Current
4.10 Measuring Dc Current
4.11 Measuring Ac Voltage
4.12 Measuring Dc Voltage
......................18
................................19
..............................20
..............................22
..............................24
..............................26
.......................................29
.............................33
..........................................35
....................................37
...........................39
.......17
4.13 Measuring Frequency
4.14 Measuring Duty
4.15 Measuring Resistance
4.16 Testing Diode
4.17 Testing Continuity
4.18 Measuring Capacitance
5. Maintenance ...........................................41
.............................41
5.1 Replacing The Batteries
5.2 Replacing Test leads .................................43
6. Accessories
............................................43
LCD (Liquid-Crystal Display)

01 02
1. Safety Information
With proper use and care, this digital multimeter will give
you years of satisfactory service.
1.1 Preliminary
1.1.1 When using the meter, the user must observe all
normal safety rules concerning:
- General protection against electric shock
- Protection of the meter against misuse.
1.1.2 When the meter is delivered, check whether it has
been damaged in transit.
1.1.3 After being stored and delivered under harsh
conditions, the meter should be checked and
confirmed whether any damages have been incurred.
1.1.4 Test leads must be kept in good condition. Before
using check whether the insulation on test leads has
been damaged and any wire has been exposed.
1.1.5 Use the test leads supplied to ensure operation
safety. If required, they must be replaced with test
leads of the same model or class.
1.2 During Use
1.2.1 Use the right input jack, function and range.
1.2.2 Do not take measurements that exceed the
protection limit values indicated in the
specifications.
1.2.3 Do not touch the metal tips of the test leads when
the meter is connected to the circuit to be
measured.
1.2.4 Keep your fingers behind the probe barriers when
taking a measurement with an effective voltage
above 60V DC or 30V rms AC.
1.2.5 Do not take voltage measurement if the value
between the terminals and earth ground exceeds
600V.
1.2.6 Select the highest range if the value scale to be
measured in the manual range is unknown.
1.2.7 Disconnect the test leads from the circuit under test
before turning the rotary selector to change
functions.
1.2.8 Do not measure the resistance, capacitance, diode
or continuity of live circuits.
1.2.9 Do not connect the meter to any voltage source
while the rotary selector is in the current,
resistance, capacitance, diode or continuity range.
1.2.10 Do not take capacitance measurements until the
capacitor to be measured has been fully
discharged.
Be extremely careful when using this meter. Improper use of this device
can result in electric shock or destruction of the meter. Take all normal
safety precautions and follow the safeguards suggested in this manual.
To exploit full functionality of the meter and ensure safe operation,
please read carefully and follow the directions in this manual. If the
equipment is used in a manner not specified by the manufacturer, the
protection provided by the equipment may be impaired.
WARNING
This meter is designed and manufactured according to safety
requirements of EN 61010-1, EN 61010-2-032, EN 61010-2-033
concerning electronic measuring instruments with a measurement
CAT III 600V and pollution degree 2 and safety requirements for
hand-held clamps for electrical measurement and test.
1.2.11 Do not use the meter near explosive gases, steam
or dirt.
1.2.12 Stop using the meter if any abnormalities or faults
are observed.

03 04
1.3 Symbols
1.4 Maintenance
1.4.1 Do not attempt to remove the rear case to adjust or
repair the meter. Such actions should only be
performed by a technician who fully understands the
meter and the danger involved.
1.4.2 Before opening the case and battery cover of the
meter, always disconnect test leads from all sources
of electric current. Disconnect the test leads from all
sources of electric current before opening the rear
case and battery cover of the meter.
1.4.3 To avoid any electric shock caused by error readings,
replace the batteries immediately when the “ ” sign
appears on the display.
1.4.4 Use damp cloth and mild detergent to clean the meter;
do not use abrasives or solvents.
1.4.5 Turn the rotary selector to OFF position to switch off
the power when the meter is not in use.
1.4.6 Remove the batteries to avoid damages to the meter
if it will idle for a long time.
2. Description
- This meter is a portable professional measuring
instrument with LCD and back light easily reading. The
'single-hand operation' design for the range switch makes
measurement simple and easy. Overload protection and
low battery indication are provided. It is an ideal multi-
function instrument with scores of practical applications
for professional, workshop, school, hobby and home use.
- The meter can perform measurements of AC/DC voltage
and current, resistance, frequency, duty, capacitance, as
well as continuity and diode test.
- Both auto range and manual range are available.
- This meter is equipped with reading hold function.
- This meter is equipped with true root mean square value
measuring function (at AC A and AC V range).
1.2.13 Do not use the meter unless its rear case and
battery cover is securely fastened in its original
position.
1.2.14 Do not store or use the meter in areas exposed to
direct sunlight, at high temperature or with high
relative humidity.
Note-Important safety information, refer to the
instruction manual.
Conforms to UL STD. 61010-1, 61010-2-032,
61010-2-033; Certified to CSA STD C22.2 NO.
61010-1, 61010-2-032,61010-2-033
Complies with European (EU) safety standards
Earth (ground) TERMINAL
Caution, possibility of electric shock
Equipment protected throughout by double
insulation or reinforced insulation.
Application around and removal from UNINSULATED
HAZARDOUS LIVE conductors is permitted.
Direct current
Alternating current
CAT III: MEASUREMENT CATEGORY III is applicable to
test and measuring circuits connected to the distribution
part of the building's low-voltage MAINS installation.
1.4.1 Do not attempt to remove the rear case to adjust or
repair the meter. Such actions should only be
performed by a technician who fully understands
the meter and the danger involved.

05 06
2.1 Names Of Components
(1) Current Clamp
(2) Clamp Lighting Bulb
(3) Panel
(4) Trigger
(5) Function Switch Button (S E L)
(6) MAX/MIN Switch Button (MAX/MIN)
(7) Relative Switch Button (REL)
(8) Liquid Crystal Display (LCD)
(9) COM Jack
(10) Input Jack
(11) Hz/Duty Switch Button (Hz/%)
(12) Reading Hold/Back Light Button (HOLD/B.L)
(13) Rotary selector
(14) OFF - power switch
(15) “+” Symbol
(16) “-” Symbol
(17) Rear Case
(18) Fixing Screw of Battery Cover
(19) Battery Cover
(20) Protective Barrier (to warn the operator of the limit of
safe access)
- This meter is equipped with inrush current measuring function.
- This meter is equipped with auto zero function (at DCA range).
- This meter is equipped with maximum value measuring
function.
- This meter is equipped with minimum value measuring function.
- This meter can measure frequency by clamp.
- This meter has function of auto power off.
- The normal function of the product may be disturbed by strong
Electro-Magnetic interference. If so, simply reset the product to
resume normal operation by following the instruction manual.
In case the function could not resume, please use the product
in other location.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
18
17
19
16
ACCORD WITH:
IEC 61010-2-032
IEC 61010-2-033
CAUTION
IEC 61010-1
600V CAT III
20
40 0A
REL

07 08
2.2 Switch, Buttons And Input Jacks
HOLD/B.L Button
- For holding the reading or control backlight
S E L Button
- For switching among measuring functions
REL Button
- The key is the relative value measurement.
Hz/% Button
- For switching between frequency and duty measuring
functions.
MAX/MIN Button
- For switching between maximum and minimum value
measuring function.
Rotary Selector
- For selecting functions and ranges.
OFF Position
- for turning off the power.
INPUT Jack
- For measuring voltage, resistance, frequency, duty,
capacitance, diode, and continuity.
COM Jack
- Common input connection for current, voltage, resistance,
frequency, duty, capacitance, diode, continuity
measurement.
Clamp
- For measuring current
2.3 LCD (Liquid-crystal display)
AC Alternating current
Direct current
Diode test
Continuity buzzer
Auto range mode
The minimum value is being measured.
The mimum value is being measured.
AUTO
MAX
MIN
DC
REL
H
%
mV, V
A
Ω, kΩ,
MΩ
Hz, kHz
nF,μF
Auto power off
Battery low
This indicates that the display data is
being held.
Percent (Duty cycle)
Milli-volts, Volts (Voltage)
Amperes (Current)
Nanofarad, Microfarad
Ohms, Kilo-ohms, Mega-ohms
(Resistance)
Hertz, Kilo-hertz (Frequency), Milohertz
DCA zero and relative measure
40
3020100
MkΩ
Hz
mVA
nμF
%
MAX MIN
REL

09 10
3. Specifications
Calibration is required once a year, to be carried out at
a temperature between 18°C and 28°C (64F° to 82F°)
and relative humidity below 75%.
3.1 General Specifications
3.1.1 Auto range.
3.1.2 Over range protection is provided for all ranges.
3.1.3 Maximum voltage between terminals and earth
ground: 600V DC or 600 rms AC
3.1.4 Operating altitude: max. 2000 meters (7000 ft.)
3.1.5 Display: 4000 counts with analog bar LCD display
3.1.6 Maximum value display: 4000 digits
3.1.7 Polarity indication: automatic; ‘-’ for negative
polarity.
3.1.8 Over range indication: ‘0L’ or ‘-0L’
3.1.9 Converter Rate: 3 times/sec; Bar graph: 30 times/sec.
3.1.10 Unit indication: function and unit.
3.1.11 Auto power off time: 15 minute.
3.1.12 Operating power : 3× 1.5V AAA batteries
3.1.13 Battery low indication: ‘ ’ on LCD
3.1.14 Temperature factor: < 0.1×Accuracy /°C
3.1.15 Operating temperature: 0°C to 40°C(32°F to 104°F)
3.1.16 Storage temperature: -10°C to 50°C(10°F to 122°F)
3.1.17 Dimension: 208×78×35mm
3.1.18 Weight: approximate 340g(including batteries)
3.2 Electrical Specifications
Ambient temperature: 23±5°C
Relative humidity: < 75%
3.2.1 AC Current
±(2.0% of rdg + 6 digits)
Accuracy
Resolution
0.01A
0.1A
Range
40A
400A
- Max. input current: 400A AC
- Frequency range: 40 to 400Hz
- Response: Average value
3.2.2 DC Current
- Max. input current: 400A DC
±(2.0% of rdg + 6 digits)
Accuracy
Resolution
0.01A
0.1A
Range
40A
400A
3.2.3 DC Voltage
Accuracy
Resolution
0.1mV
0.001V
Range
400mV
4V
0.01V
40V
±(1.0% of rdg + 2digits)
0.1V
400V
±(0.7% of rdg + 2digits)
- Input impedance: 10MΩ
- Max. input voltage: 600V DC
1V
600V ±(0.8% of rdg + 2digits)

11 12
3.2.4 AC Voltage
Accuracy
Resolution
0.001V
0.01V
Range
4V
40V
0.1V
400V
1V
600V
±(0.8% of rdg + 3digits)
±(1% of rdg + 4digits)
- Input impedance: 10MΩ
- Max. input voltage: 600V rms AC
- Frequency range: 40 to 400Hz
- Response: Average value
3.2.5 Frequency
3.2.5.1 By A range ( from current clamp):
±(1.5% of rdg + 5 digits)
Accuracy
Resolution
0.1Hz
Range
10Hz
1kHz
0.0011kHz
0.0011kHz
>1kHz
- Measurement range: 10 ~ 1kHz
- Input current range: >40A rms AC (higher input
current at higher frequency)
- Max. Input current: 400A rms AC
Note:
At small voltage range, unsteady readings will appear
before the test leads contact the circuit. This is normal
because the meter is highly sensitive. When the test
leads contact the circuit, the true reading will be shown.
3.2.5.2 By ACV range:
Accuracy
Resolution
0.01Hz
0.001kHz
Range
10Hz
1kHz
0.01kHz 10kHz
>10kHz
±(1.5% of rdg + 5 digits)
- Measurement range: 10 ~ 10kHz
- Input voltage range:>0.6V rms AC (higher input
voltage at higher frequency)
- Input impedance: 10MΩ
- Max. input voltage: 600V rms
0.01kHz
3.2.5.3 By Hz/DUTY range
Accuracy
Resolution
0.001Hz
0.01Hz
Range
9.999Hz
99.99Hz
0.1Hz 999.9Hz
9.999kHz ±(0.5% of rdg + 3 digits)
- MAX. Input voltage:600V AC (rms)
0.001kHz
99.99kHz
999.9kHz
9.999MHz 0.001MHz
0.1kHz
0.01kHz
Take it only as referance
Take it only as referance

13 14
Accuracy
Resolution
0.1Ω
0.001kΩ
Range
400Ω
4kΩ
0.01kΩ 40KΩ
0.1kΩ400kΩ
±(0.8% of rdg +3digits)
0.001MkΩ
4MΩ
0.01MΩ
40MΩ
- Open circuit voltage: 0.23V
3.2.7 Resistance
±(1.2% of rdg + 3digits)
3.2.8 Diode
FunctionResolution
Range
Displaying approximate
for ward voltage of diode
0.001V
- Forward DC current~1mA
- Reversed DC voltage~3.0V
Resolution
Range
Built-in buzzer will sound,
if resistance is lower than
50±20Ω.
0.1Ω
- Open circuit voltage~0.4V
3.2.9 Continuity
3.2.6 Duty Cycle
Accuracy
Resolution
0.1%
Range
1.0% - 99.9%
±3.0%
3.2.6.1 By A range ( from current clamp):
- Frequency response: 10 ~1kHz
- Input current range:> 4A rms AC
- Max. input current: 400A
3.2.6.2 By ACV range:
- Frequency response: 10 ~ 10 kHz
- Input voltage range:>1V rms AC
- Input impedance: 10MΩ
- Max. input voltage: 750V rmsAC
3.2.6.3 By Hz/DUTY range
- Frequency response: 1 ~ 10 MHz
- Input voltage range:>500mV rms 3.2.10 Capacitance
Accuracy
Resolution
0.01nF
Range
40nF
400nF
4µF
0.01µF40µF
±(4.0% of rdg + 5 digits)
0.1µF
400µF
0.1nF
0.001µF
4000µF 1µF
Function

15 16
4. Operation Instruction
4.1 Holding Readings
4.1.1 Press the “HOLD/B.L” button to hold the readings
while taking measurement and the value on the
display will be held.
4.1.2 Press the “HOLD/B.L” button again to release
the reading hold function.
4.2 Switching Rel
1) REL key is the relative value measurement
communication transmission key that acts with
trigger. Press this key will enter into the relative
value measurement mode. The system will save the
display value in the memory as the reference value.
When doing the measurement later, the display
value will be the difference value that the entry
value deducts the reference value.
2) Press REL key will enter into the Manual
Measurement Mode automatically.
3) In REL measurement status, press the key again,
the REL function will be relocked.
4) Press the key in HOLD status, HOLD function will be
cancelled. The system will save the display value in
the memory as the reference value. When doing the
measurement later, the display value is the
difference that the entry value deducts the
reference value.
5) Press SELECT Key or use Mode Switch will cancel
REL measurement mode, and go back to the
normal mode (REL will disappear in the LCD).
6) OL triggering: Under REL mode, OL shows when
input value larger than the allowed value of the
measurement mode. Press the key again, the
relative measurement function will be cancelled.
Disable to enter REL mode when OL shows.
7) No analog section bar function under REL mode.
4.3 Switching Frequency Or Duty
4.3.1 During working at the voltage or current ranges,
press the “Hz/%” button one time, frequency of
the voltage or current will be measured.Press the
“Hz/%” button twice, the meter will be changed
into the duty range for measuring the duty cycle
of the voltage or current. At the same time, the
meter is changed into manual mode.
4.3.2 Press the “Hz/%” button again, meter will be
back to the condition of the voltage or current
measuring.
Note:
During working at maximum or minimum value
measuring function, the meter can't be changed into
frequency or duty cycle measuring mode.
4.4 Switching Maximum Or Minimum Value
4.4.1 press the maxim/minimum button to enter into
the maximum mode, the maximum will always be
measured. and press this button again, it is the
same with the minimum.
4.4.2 After entering into maximum/minimum mode,
there is no more analog function and auto power
off function will also be canceled too.
4.4.3 After entering into maximum/minimum mode,
the maximum/minimum data will be recorded
automatically.
4.4.4 Press the max/min button for more than 2
seconds, it will be set into the normal mode.

- LED, which requires a larger working current, is the
main source of back light. Although the meter is
equipped with a timer set at 15 seconds (i.e. the back
light will be off automatically after 30 seconds),
frequent use of the back light will shorten the life of
the batteries. Therefore, do not use the back light
unless necessary.
- When the battery voltage is<3.7V, the symbol “ ”
(battery low)will appear on the LCD. When the back
light is on, even if the batter is>3.7V, the “ ” may
appear because of its large working current which
will cause the voltage to drop. (The accuracy
of the measurement cannot be assured when the
“ “ symbol appears.) In this case, you need not
replace the batteries yet. Normally, the batteries
can last until the “ ” appears when the back light is
not being used.
17 18
1) During measuring maximum or minimum value, the
meter will be set to manual mode automatically.
2) During working at frequency or duty measuring
function, the meter can't be changed into maximum
or minimum value measuring mode.
Note:
4.5 Switching Functions
1) SELECT Key is a function selection key that acts
with trigger. Press the key can choose the needed
measurement mode: To choose DC or AC in DC/AC
status, to choose Diode or Buzzer in Diode/Buzzer
status, to choose Ohm, Cap, Diode or Buzzer in
Ohm/Cap/Diode/ Buzzer status.
2) Press the key then turn on the power, the Auto
Power-off function will be cancelled, the signal
"APO"disappears in LCD, and enter into Sleep
Status (Power-Off). Press the key then power on
will have the Auto Power-Off function.
4.6 Back Light And Clamp Lighting Bulb
4.6.1 Press the “HOLD/B.L” button for two or more
seconds to switch on the back light if the light
in the environment is too dim for taking reading,
which will last for 15 seconds.
4.6.2 During the back light is working, press the
“HOLD/B.L” button for two or more seconds, it
will be turned off.
4.6.3 At the current range, when the back light is
switched on, the clamp lighting bulb will be turned
on at the same time.
Note:
4.7 Auto Power Off
4.7.1 If the mode switch or keys of the meter is no
action within 15 minutes, the system will power
off automatically (sleep mode). In Auto
Power-off status, press any key, the meter will
"Auto Power-On" (Operation Mode)
4.8 Preparating For Measurement
4.8.1 Switch on the power by turning the rotary selector.
If the battery voltage is lower than 3.7V, the “ ”
symbol will appear and the batteries should be
replaced.
4.8.2 The “ ” symbol shows that the input voltage or
current should not exceed the specified value in
order to protect the internal circuit from damage.

19
4.9 Measuring AC Current
WARNING
Beware of Electrocution.
Ensure that the test leads are disconnected
from the meter before making current clamp
measurements.
4.9.1 Set the rotary selector to the 40A or 400A range
position.
4.9.2 push the REL key make sure the LCD display zero
if the unsteady reading appear before
measurement.
4.9.3 Press the trigger to open jaw. Fully enclose only
one conductor.
4.9.4 Take the reading on the LCD.
Note:
1) Do not put more than one cable into
the jaw during test, otherwise incorrect
test value might be obtained.
2) For optimum results, center the conductor in the jaw.
3) At the manual range mode, when only ‘O L’ is shown
on the LCD, it means the measurement has
exceeded the range. A higher range should
be selected.
4.8.3 Turn the rotary selector to the required function
and range to be measured.
4.8.4 Connect the common test lead first and then the
charged test leads when making connection.
Take away the charged test lead first when
disconnecting.
4) If the scale of the value to be measured is unknown
beforehand, set the range to the highest.
4.10 Measuring DC Current
WARNING
Beware of Electrocution.
Ensure that the test leads are disconnected
from the meter before making current clamp
measurements.
4.10.1 Set the rotary selector to the 40A or 400A range
position.
4.10.2 Press the SEL key turn to DC current
measurement mode..
4.10.3 Press the "REL" button, the meter will be set
to zero.
4.10.4 Press the trigger to open jaw. Fully enclose only
one conductor.
4.10.5 Take the reading on the LCD.
4.10.6 Symbol "-" will be displayed on LCD if the
direction of the current is negative.
Note:
1) Do not put more than one cable into the jaw during
test, otherwise incorrect test value might be obtained.
2) For optimum results, press the "REL" button to make
the meter get into zero first.
3) For optimum results, center the conductor in the jaw.
4) At the manual range mode, when only “O L” or “-O L”
is shown on the LCD, it means the measurement has
exceeded the range. A higher range should be selected.
5) Under the manual range mode, when the scale of the
value to be measured is unknown beforehand, set
the range to the highest.
20
5) “ ” means the maximum input current is
400A rms AC.
6) " " means the maximum input current is 400A DC.

21 22
4.11 Measuring AC Voltage
WARNING
Beware of Electrocution. Pay special attention to
avoid electric shock when measuring high voltage.
Do not input the voltage which more than750V rms
AC.
4.11.1 Plug the black test lead into the COM jack and the
red test lead into the INPUT jack.
4.11.2 Set the rotary selector to position to make the
meter get into AC V range.
4.11.3 Connect the test leads to the voltage source or load
terminals for measurement.
4.11.4 Take the reading on the LCD.
Note:
1) “ ” means the maximum input voltage is 750V True
RMS AC.
2) If the test result is more than 750V True RMS AC,
symbol “OL” will be displayed on LCD and the build-up
buzzer will sound.
V
Correct Incorrect
400 A
REL REL
REL

9V
23 24
4.12 Measuring DC Voltage
WARNING
Beware of Electrocution.
Pay special attention to avoid electric shock
when measuring high voltage.
Do not input the voltage which more than
1000V DC.
4.12.1 Plug the black test lead into the COM jack and
the red test lead into the INPUT jack.
4.12.2 Set the rotary selector to at the V range
position.
4.12.3 Connect the test leads to the voltage source or
load terminals for measurement.
4.12.4Take the reading on the LCD. The polarity
symbol denotes the polarity of the end
connected by the red test lead.
Note:
1) At small voltage range, unsteady readings will
appear before the test leads contact the circuit.
This is normal because the meter is highly sensitive.
When the test leads contact the circuit, the true
reading will be shown.
2) “ ” means the maximum input voltage is 1000V DC.
3) If the test result is more than 1000V DC, symbol “O L”
will be displayed on LCD and the build-up buzzer
will sound.
40 0A
REL

25 26
4.13 Measuring Frequency
4.13.1 By A range (from current clamp):
WARNING
Beware of Electrocution.
Ensure that the test leads are disconnected
from the meter before making current clamp
measurements.
4.13.1.1 Set the rotary selector to the A range
(A~ or A ) position.
4.13.1.2 Press the trigger to open jaw. Fully enclose
only one conductor.
4.13.1.3 Press the “Hz/%” to switch to the frequency
measurement.
4.13.1.4 Take the reading on the LCD.
Note:
1) Do not put more than one cable into the jaw during
test, otherwise incorrect test value might be obtained.
2) Frequency test range is 10Hz - 1kHz.‘00.0’ will be
displayed on LCD if the test frequency is lower than
10.0 Hz. It is possible to test the frequency which is
higher than 1 kHz but the tolerance of the test result
can not be ensure.
3) “ ” means the maximum input current is
400A rms AC.
Correct Incorrect
REL REL

27 28
4.13.2 By V range:
WARNING
Beware of Electrocution.
Pay special attention to avoid electric shock
when measuring high voltage.
Do not input the voltage which more than
750V rms AC.
4.13.2.1 Plug the black test lead into the COM jack
and the red test lead into the INPUT jack.
4.13.2.2 Set the rotary selector to the V range
position.
4.13.2.3 Press the "Hz/%" to switch to frequency
measurement.
4.13.2.4 Connect test leads to the two ends of the
source or load for measurement.
4.13.2.5 Take the reading on the LCD.
Note:
1) Frequency test range is 10Hz -10kHz. It is possible
to test the frequency which is higher than 10kHz but
the tolerance of the test result
can not be ensure.
2) “ ” means the maximum input voltage is
750V rms AC.
4.13.3 By HZ/DUTY range:
WARNING
Beware of Electrocution.
Pay special attention to avoid electric shock
when measuring high voltage.
Do not input the voltage which more than
250V rms AC.
4.13.3.1 Plug the black test lead into the COM jack and
the red test lead into the INPUT jack.
4.13.3.2 Set the rotary selector to the HZ/DUTY
range position.
4.13.3.3 Connect test leads to the two ends of the
source or load for measurement.
4.13.3.4 Take the reading on the LCD.
400 A
REL

29 30
4.14 Measuring Duty
4.14.1 By A range ( from current clamp):
WARNING
Beware of Electrocution.
Ensure that the test leads are disconnected
from the meter before making current clamp
measurements.
4.14.1.1 Set the rotary selector to the A range position.
4.14.1.2 Press the trigger to open jaw. Fully enclose
only one conductor.
4.14.1.3 Press the "Hz/%" to switch to the DUTY
measurement.
4.14.1.4 Take the reading on the LCD.
Note:
1) Do not put more than one cable into the jaw during
test, otherwise incorrect test value might be obtained.
2) If the duty cycle is less than 10%, symbol 'UL' will be
displayed on LCD; if the duty cycle is more than 94.9%,
symbol 'O L' will be displayed on LCD.
3) The input signal frequency range is 10 – 1kHz. It is
possible to test duty cycle of the higher than 1 kHz
frequency signal, but the tolerance of the test result
can not be ensure.
4) “ ” means the maximum input current is 400A rms
AC. Correct Incorrect
REL REL

31 32
4.14.2 By V range:
WARNING
Beware of Electrocution.
Pay special attention to avoid electric shock
when measuring high voltage.
Do not input the voltage which more than
750V rms AC.
4.14.2.1 Plug the black test lead into the COM jack and
the red test lead into the INPUT jack.
4.14.2.2 Set the rotary selector to the V range position.
4.14.2.3 Press the "Hz/%" to switch to DUTY
measurement.
4.14.2.4 Connect test leads to the two end of the source
or load for measurement.
4.14.2.5 Take the reading on the LCD.
Note:
1) If the duty cycle is less than 10%, symbol 'UL' will be
displayed on LCD; if the duty cycle is more than
94.9%, symbol 'O L' will be displayed on LCD.
3) The input signal frequency range is 10 – 10 kHz. It is
possible to test duty cycle of the higher than 10 kHz
frequency signal, but the tolerance of the test result
can not be ensure.
3) “ ” means the maximum input voltage is
750V rms AC.
40 0A
REL

33 34
4.15 Measuring Resistance
WARNING
Beware of Electrocution.
When measuring in-circuit resistance, make
sure that the power of the circuit under test
has been turned off and that all capacitors
have been fully discharged.
4.15.1 Plug the black test lead into the COM jack and the
red test lead into the INPUT jack.
4.15.2 Set the rotary selector to the range position to
make the meter get into range.
4.15.3 Connect the test leads to the ends of the resistor
or circuit for measurement.
4.15.4 Take the reading on the LCD.
Note:
1) When the input is open, “O L”will appear on the LCD to
indicate that the range has been exceeded.
2) For measuring resistance above 1MΩ, t may take a
few seconds to get a steady reading. This is normal for
high resistance reading.
4.14.3 By HZ/DUTY range:
WARNING
Beware of Electrocution.
Pay special attention to avoid electric shock
when measuring high voltage.
Do not input the voltage which more than
250V rms AC.
4.14.3.1 Plug the black test lead into the COM jack and the
red test lead into the INPUT jack.
4.14.2.2 Set the rotary selector to the HZ/DUTY range
position.
4.14.2.3 Press the "Hz/%" to switch to DUTY measurement.
4.14.2.4 Connect test leads to the two end of the source or
load for measurement.
4.14.2.5 Take the reading on the LCD.
Note:
1) If the duty cycle is less than 10%, symbol 'UL' will be
displayed on LCD; if the duty cycle is more than 99.9%,
symbol 'O L' will be displayed on LCD.
3) The input signal frequency range is 10 – 10 kHz. It is
possible to test duty cycle of the higher than 10 kHz
frequency signal, but the tolerance of the test result can
not be ensure.
3) “ ” means the maximum input voltage is 750V rms AC.
Ω
Ω
400A
REL

35 36
4.16 Testing Diode
4.16.1 Plug the black test lead into the COM jack and
the red test lead into the INPUT jack.
4.16.2 Set the rotary selector to the range position.
4.16.3 Press the "SEL" button to switch to test.
4.16.4 Connect the red test lead to the anode and the
black test lead to the cathode of the diode for
testing.
4.16.5 Take the reading on the LCD.
Note:
1) The meter will show the approximate forward voltage
drop of the diode.
2) When the test leads have been reversed or open, ‘O L’
will appear on the LCD.
Ω
40 0A
REL