Mastech MS2025A User manual

MS2025A
Digital Clamp Meter
Operation Manual
CAT III
1000V

CONTENTS CONTENTS
1. Safety Information
1.1 Preliminary
1.2 Usage
1.3 Symbols
1.4 Maintenance
2. Description
2.1 Part Name
2.2 Switch, Button And Input Jack Description
2.3 LCD Display
3. Specifications
3.1 General
3.2 Technical Indicators
4. Operating Guidance
4.1 Reading Hold
4.2 Manual Measuring Range
4.3 Frequency/Duty Ratio Switch
4.4 Max./Min. Measurement Choice
4.5 Function Switch
4.6 REL/INRUSH Measurement
4.7 Back Light And Clamp Head Light
4.8 Automatic Power-Off
4.9 Measurement Preparation
4.10 Current Measurement
4.11 Voltage Measurement
4.12 Frequency And Duty
Ratio Measurement
4.13 Resistance Test
4.14 Diode Test
4.15 Circuit Continuity Test
4.16 Capacitance Measurement
5. Maintenance
5.1 Replace Battery
5.2 Replace Probe
6. Accessories
4.17 NCV Measurement
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1.2.13 Unless the meter bottom case and the battery
cover are completely fastened completely, do not
use the meter.
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 1000V, and pollution degree 2 and
safety requirements for hand-held clamps for electrical
measurement and test.

03 04
1.3 Symbols
1.4 Maintenance
1.4.1 Don't try to open the meter bottom case to adjust or
repair. Such operations can only be performed by
technicians who fully understand the meter and
electrical shock hazard.
1.4.2 Before opening the meter bottom case or battery
cover, remove probe from the circuit to be measured.
1.4.3 To avoid wrong readings causing electric shock,
when " " appears on the meter display, replace
the battery immediately.
1.4.4 Clean the meter with damp cloth and mild detergent.
Do not use abrasives or solvents.
1.4.5 Power off the meter when the meter is not used.
Switch the measuring range to OFF position.
1.4.6 If the meter is not used for long time, remove the
battery to prevent the meter being damaged.
2. Description
- The meter is a portable, professional measuring
instrument with LCD display and back light for easy
reading by users. Measuring range switch is operated by
single hand for easy operation with overload protection
and low battery indicator. It is an ideal multifunction
meter for professionals, factories, schools, fans and
family use.
- The meter is used for AC current, DC current, AC voltage,
DC voltage, frequency, duty ratio, resistance,
capacitance measurement, circuit connection, diode
test and non-contact voltage detection.
- The meter has automatic measuring range and manual
measuring range.
- The meter has reading hold function.
- The meter has max. measuring function.
- The meter has min. measuring function.
- The meter has clamp head frequency measurement
function.
- The meter has auto power-off function.
- The meter has relative measuring function.
1.2.14 Don't store or use the meter in the conditions of direct
sunlight, high temperature and high 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
Both direct and alternating current
CAT III
It is applicable to test and measuring circuits
connected to the distribution part of the
building's low-voltage MAINS installation.

05 06
(1) Current clamp head: used for current measurement.
(2) Clamp head light
(3) Panel
(4) Trigger
(5) Function choice button (FUNC)
(6) Relative measurement button
(7) Frequency/duty ratio switch button (Hz/%)
(8) LCD display
(9) Common end jack
(10) Resistance, capacitance, voltage, frequency, diode
and continuity input jack
(11) Maximum/minimum choice button (MAX/MIN)
(12) Reading hold/Back light button (B.L/ HOLD)
(13) Transfer switch
(14) NCV indicator
2.1 Part Name
15
13
12
11
109
8
7
5
4
2
6
3
1
14
(15) Protective Barrier
(to warn the operator of the limit of safe access)

09
Battery undervoltage indication: LCD displays symbol.
Temperature coefficient: less than 0.1×accuracy/°C
Operational temperature: 18°C~28°C
Storage temperature: -10°C~50°C
Dimension: 238×92×50mm
Weight: about 420g (include battery)
3. Specifications
Automatic measuring range and manual measuring range.
Full measuring range overload protection.
The maximum allowable voltage between
measurement end and ground: 1000V DC or 750V AC
Operational height: maximum 2000m
Display: LCD
Displayed maximum value: 5999 digit.
Polarity indication: automatical indication, '-' means
negative polarity.
Exceeding measuring range display: 'OL' or '-OL'.
Sampling rate: about 3 times/sec.
Unit display: has function and power unit display.
Auto off time: 15 min
Power supply: DC 9V battery (type NEDA 1604, 006P or
6F22)
The meter should be recalibrated under the condition of
18°C~28°C, relative humidity less than 75% with the
period of one year.
3.1 General
3.2 Technical Indicators
Environment temperature: 23±5°C, relative humidity
(RH):<75%
3.2.1 True RMS Zero Input Characteristic
3.2.1.1 For measuring non-sinusoidal wave signal, uses
true RMS measuring method, which has less error
than traditional average response measuring
method.
3.2.1.2 The true RMS meter can accurately measure
non-sinusoidal wave signal, but if it is in AC
function mode, when there is no signal to be
measured (input terminal short circuit in AC
voltage mode), clamp meter may show a reading
from 1 to 50. These deviating readings are normal.
In the designated measurement range, they will
not affect the accuracy for multimeter measuring
AC.
3.2.1.3 The true RMS can be measured only when input
signal reaches a certain level. Therefore, the
measuring range of AC voltage and current should
be specified at 2% ~100% of full range.

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- Forward DC current is about 1mA
- Backward DC voltage is about 3.3V
- Overload protection: 250V DC or AC (RMS)
1) In the process of measurement, if reading hold is
required, press “HOLD/B.L” key, the value on the
display will be locked. Press “HOLD/B.L” key again to
cancel reading hold state.
4. Operating Guidance
4.1 Reading Hold
4.2 Manual Measuring Range
RANGE key is automatic/manual measuring range key to
trigger mode. The preset one is automatic measuring
range. Press to switch to manual measuring range. In the
manual measuring range mode, click once to change to
upper range. Continue to the top range, then continue to
press this key to change to the bottom range, followed by
recycling. If this key is pressed more than 2 sec, it will
switch back to automatic measuring range state.
In capacitance and frequency measurement state, rhw
manual measuring range button is invalid.
Note:
4.3 Frequency/Duty Ratio Switch
1) When the meter is in AC voltage mode, if “Hz/%” button
is pressed, the meter will measure Hz, and measure AC
voltage, AC current signal frequency. Click “Hz/%”
button again, the meter will measure DUTY cycle, and
measure voltage and current signal duty ratio. If it is in
HZ/DUTY position, pressing HZ % key will switch
between HZ and DUTY by recycling.
2) If “Hz/%” button is pressed again, the meter will revert
to voltage, current measurement state.
Note:
The meter is in the maximum/minimum value
measurement state, it can't switch to frequency, duty
ratio measurement mode.

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4.4 Max/Min Measurement Choice
1) Press “MAX/MIN” key to enter MAX mode, and always
keep measurement maximum value; press “MAX/MIN”
key again, the meter will enter minimum value
measurement state; press “MAX/MIN” key for the third
time, the meter will display the difference of maximum
and minimum value; press “MAX/MIN” key to repeat
the above operations by recycling.
2) After entering MAX or MIN mode, it will automatically
save the measured maximum or minimum value.
3) If the user presses “MAX/MIN” key more than 2 sec,
the meter will restore normal measuring range.
Note:
1) When the meter is in the maximum/minimum value
measurement state, it is in manual measuring range
mode.
2) When the meter is in the frequency, duty ratio
measurement state, it can't switch to maximum/
minimum value measurement mode.
1) In the resistance mode, press "FUNC" button, it will
switch among resistance, diode and continuity
detection by recycling.
2) In the voltage and current mode, press "FUNC" button
to switch between AC and DC.
4.5 Function Switch
1) REL/INRUSH button is relative value measurement
button. Operated by tapping this button, it will enter
relative value measurement mode,. The current display
value can be stored in the memory as reference value.
When the user measures later, the display value is the
difference for input value minus reference value. ie.
REL△(current reading)= Input value - Reference value.
2) The relative value measurement can only be performed
in the manual mode.
1) In the process of measurement, if ambient light is too
dark to read, press “B.L/HOLD” key to open the
backlight, the backlight will automatically turn off after
about 30 seconds.
2) During this period, pressing “B.L/ HOLD” key more
than two seconds will turn off backlight.
3) In the current mode, the meter will turn on backlight
and, at the same time, it will turn on clamp head light.
Backlight is LED with high current draw. The backlight
will turn off in about 30 seconds. If backlight is used
often, it will shorten battery life, so do not use backlight
excessively.
4.6 REL/INRUSH Measurement
4.7 Back Light And Clamp Head Light

1) If there is no operation during any 15 minutes after
turning the machine on, the meter will enter suspended
stated, automatically powering off to save the battery.
Within 1 minute before shutdown, buzzer will sound five
times. The meter will then enter a dormant state.
2) After automatic power-off, press FUNC key, the meter
will turn on again.
3) If the user holds “FUNC” key when powering on, it will
cancel automatic power-off function.
1) Measuring switch is placed to position A. At this time,
the meter is in AC current measurement state. Choose
appropriate measuring range.
2) Hold the trigger, open clamp head, clip one lead of
measurement circuit to be tested inn the clamp.
3) Read the current value on the LCD display.
4.11 Voltage Measurement
Electric shock hazard.
Pay special attention to avoid shock when
measuring high voltage.
Don't input voltage more than AC750 RMS.
Warning
1) Insert black probe to COM jack, insert red probe to
INPUT jack, choose appropriate measuring range.
2) Place transfer switch to AC voltage or position.
At this time, the meter is in the DC voltage
measurement state. To measure AC voltage, press
FUNC button to enter AC voltage measurement state.
3) Connect the probe with voltage source or both ends
of load in parallel for measurement.
4) Read the voltage on the LCD.
VmV

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Note:
1) In the small voltage measuring range, the probe is
not connected with the circuit to be tested, and the
meter may have fluctuating readings, which is normal
and caused by the meter's high sensitivity. When the
meter is connected with the circuit to be tested, you
will get actual measured value.
2) In the relative measurement mode, automatic
measuring range is invalid.
3) “ ”indicates that maximum input voltage is 750V AC
or 1000V DC. Maximum input voltage at mode mV is
600mV DC or AC.
4) If the readings measured by the meter is more than
750V rms AC, it will send out "beep" alarm.
4.12 Frequency And Duty Ratio Measurement
Electric shock hazard.
Remove the probe from the meter before
measuring with current clamp.
Warning
(1) Measuring switch is placed to position A .
(2) Hold the trigger, open clamp head, clip one lead of
measurement circuit to be tested in the clamp.
(3) Press Hz/% key to switch to frequency measuring
state.
(4) Rad the current value on the LCD display.
(5) Pressing Hz/% again can enter duty ratio measuring
state.
1) Clamp head measuring frequency
(through AC current):
Note:
(1) Clamping two or more leads of circuit to be tested
simultaneously will not get the correct
measuring results.
(2) Frequency measurement range is 10Hz~1kHz the
frequency to be tested is less than 10Hz, or if
frequency is higher than 10 kHz, accuracy is
not guarantee
(3) Duty ratio measuring range is 10 ~ 95%.
(4) “ ”means that maximum input current is 1000A AC
(RMS).
2) In Voltage Measurement Mode:
Electric shock hazard.
Pay special attention to avoid shock when
measuring high voltage.
Don't input voltage more than AC 750 RMS.
Warning
(1) Insert black probe to COM jack, insert red probe
to INPUT jack.
(2) Place transfer switch to or position, press
FUNC to enter AC voltage measurement state.
(3) Prss “Hz/%” key to switch to frequency measuring
state.
(4) onnect the probe with signal or both ends of load in
parallel for measurement.
(5) VRead on the LCD.
(6) Pressing “Hz/%”again can enter duty ratio measurig
state.
mV
V

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(1) Frequency measurement range is 10Hz~1kHz
When the frequency to be tested is less than 10Hz,the
LCD will show “00.0” Masuring frequency higher than
10kHz is possible, but ccuracy is ot guarantee
(2) Duty ratio measuring range is 10 ~ 95%.
(3) “ ”means that maximum input voltage is 750V AC
(RMS).
Note:
3) In HZ/DUTY Measurement Mode:
Electric shock hazard.
Pay special attention to avoid shock when
measuring high voltage.
Don't input voltage more than AC 250V RMS.
Warning
(1) Insert black probe to COM jack, insert red probe to
NPUT ack.
(2) Transfer switch is placed to position HZ.
(3) Connect the probe with signal or both ends of load in
parallel for measurement.
(4) Read on the LCD.
(5) Pressing “Hz/%” again can enter duty ratio measuring
state.
Frequency measurement range is 10Hz~1kHz When the
frequency to be tested is more than 10Hz,the LCD will
show “00.0”measuring frequency higher than 10 kHz is
possible, but accuracy is not guarantee
Note:
4.13 Resistance Test
Electric shock hazard.
When measuring circuit impedance,
determine that the power supply is
disconnected and the capacitor in the circuit
is completely discharged.
Warning
1) Insert black probe to COM jack, insert red probe to
INPUT jack.
2) Place measuring range switch to position. At this
time, the meter is in the measurement state.
3) Connect the probe to the both ends of resistor or circuit
to be tested for measurement.
4) LCD will show readings.
Ω

4.17 NCV Measurement
1) Turn the meter to NCV mode.
2) Place the meter top close to the conductor. When test
voltage is greater than 110 Vac (RMS), when the meter
is close to the conductor, the meter induction voltage
indicator will turn on and the buzzer will give an
alternating high-low alarm sound.
1. Even there is no indication, voltage may exist still.
Don't use non-contact voltage detector to judge
whether there is voltage in the wire. Detection
operation could be affected by socket design,
insulation thickness, type and other factors.
Note:

1. If the symbol “ ” appears, it means that the batteries
should be replaced.
2. Loosen the screw of the battery cover and remove it.
3. Replace the used battery with a new one.
4. Return the battery cover and tighten the screw.
To avoid electric shock, make sure that the test leads have
been clearly move away from the circuit under
measurement before opening the battery cover.
Test Probe 1 pair
Operating Manual 1 pcs
9V DC battery (6FF2)
1 pcs
1)
2)
3)
Case 1 pcs
4)
6. Accessories
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2. When inputting voltage on the meter input terminal,
due to the existence of the induced voltage, voltage
induction indicator also may light.
3. External sources of interference (such as flashlight,
motor, etc.) may incorrectly trigger non-contact voltage
detection.
5. Maintenance
5.1 Replace Battery
The battery polarity can't be reversed.
Note:
5.2 Replace Probe
WARNING
Replace test leads if leads become damaged or worn.
Use meet EN 61010-031 standard, rated CAT III 1000V,
or better test leads.
WARNING
To avoid electric shock, make sure the probes are
disconnected from the measured circuit before
removing the rear cover. Make sure the rear cover is
tightly screwed before using the instrument.
WARNING

R-00-05-1803