Prokit's Industries MT-1820 User Manual

MT-1820

3 5/6 Dual Display DMM
w/USB Connector

User’s Manual

1st Edition, 2013

©2013 Copyright by Prokit’s Industries Co., Ltd.

Index

General…………………………………………………………………. 2

Open Package Inspection…………………………………..……. 2

Safety Note………………………………………………………… 3

Safety Symbol Description…………………………………...4

Front Panel Description …………………………………...5

Property………………………………………………………………….7

DC Voltage (DCV) …………………………………………………7

AC Voltage (ACV) …………………………………………………8

DC Current (DCA) …………………………………………………9

AC Current (ACA) …………………………………………………11

Resistance …………………………………………………12

Diode and Continuity Test ……………………………………...14

Capacitance (C) …………………………………………………15

Frequency (Hz) ………………………………………………… 16

Transistor Test …………………………………………………18

Temperature Test …………………………………………………19

Other Function & Instrument Maintenance …………………… 20

Fault Elimination………………………………………………………22

1

General

The instrument is a high performance, high accuracy, 3 5/6 dual

display DMM w/usb connector multimeter, it uses the LCD with

24mm high figure to make the reading clear, the display simple and

the operation convenient.

The instrument can measure DC and AC voltage, DC and AC

current, Resistance, Capacitance, Frequency, Duty Circle,

Transistor, Diode and Continuity test; And it also has the features of

Bar Graph, Unit Indication, Data Hold, Relative Value Measurement

(REL), USB Interface, AUTO/MANUAL range selection, Auto Power

Off and Alarm Buzzer. The instrument adopts the directly driven 4

digits microprocessor and dual-integral A/D converter, which

provide the high solution and high accuracy digital displaying driver.

Because of its outstanding features, it is an excellent tool and most

suitable for lab, factory, maintenance and repair users.

Open-package Inspection

Open the package box and take out the instrument, check the

following accessories carefully. If any accessory was lost or

damaged, please contact the manufactory at once.

• Digital Multimeter 1pc

• Operation Manual 1pc

• Test Lead 1set

• Temperature Cable 1pc

• USB Cable 1pc

• Software disc 1pc

• Transistor test accessory 1pc

2

Safety Note

The instrument meets the standard of IEC1010 (safety standard

promulgated by the International Electrician Committee). Design

and manufacture complied with the standard of Pollution Degree

Warning

To avoid endangering the users safety, should read the operation
manual carefully before operation, and strictly obey the safety
warning information and operation description when use the
instrument.

1. Caution to avoid the electric shock when measuring the voltage
higher than 30V, the current higher than 10mA, AC Power Lines
with Inductive Load and the AC Power Lines during the period of
Electric Power Fluctuation.

2. Before measuring, should check if the function knob is set in the
correct range, make sure the test lead connects reliably, links up
correctly, and insulates properly to avoid the electric shock

3. It meets the requirements of the safety standard only to use the
instrument with the equipped test lead. If the test lead is broken,
should replace it by the same type and same electric specification
test lead.

4. Do not replace the inside fuse by the unconfirmed one. Only
replace it by the same type and specification fuse. Before
replacement, should keep the test lead off the tested point to make
sure there is no any signal at the input terminal.

5. Do not replace the inside battery by the unconfirmed one. Only
replace it by the same type and electric specification battery. Before
replacement, should keep the test lead off the tested point to make
sure there is no any signal at the input terminal.

6. When measuring electricity, do not connect the body with the
ground directly, and do not touch the possible exposed metal
terminal, output socket or lead clamp with ground potential. Usually
use the dry cloth, rubber overshoes, rubber cushion and other
insulated materials to keep the body isolated with the ground.

3

7. Do not store and use the instrument in high humility, high
temperature, combustible, explosive and strong magnetic places.

8. It is possible to damage the instrument and endanger the safety
of the users when measuring the voltage over the range limit. The
allowed maximum voltage is printed on the front panel of the
instrument, do not input the range limit specified to avoid the
electric shock and instrument damage

9. Do not measure any voltage when connecting the test lead with
the current terminal to avoid damaging the instrument and
endangering the safety of the users.

10. Do not try to calibrate or repair the instrument, should operate it
by the specially trained or qualified professional people.

11. The function/range selection knob should be set in the correct
range when measuring. When switching the function/range
selection knob, keep the test lead off the tested object to make sure
there is no any signal at the input terminal. Do not switch the
function/range selection knob when measuring.

12. When LCD displays “
make sure the measuring accuracy.

13. Do not allow to measure the voltage when connecting the test
lead with the current terminal!

14. Do not try to modify the inner circuit at will to avoid damaging
the instrument and endangering the safety of the users.

”, please replace the battery in time to

Safety Symbol Description

Warning

High Voltage!
Dangerous!

GND

Dual Insulation

Low Battery

4

DCA

ACA

DCA & ACA

Meets the direction
of European IEC

Fuse

Front Panel Description

1. Instrument Model Number

2. LCD Display

3. RANGE: Auto Range/ Manual

Range switch, the default is set as

Auto Range mode when turning

on, press the button and switch to

Manual Range. At the Manual

Range mode, press the button

once, the range is switched to the

higher one, press the button again

to switch the range to the lowest

one when measuring the highest

range, the cycle is in proper order

from low to high. Keep pressing the button for 2 sec, return to

Auto Range mode. There is no Manual Range mode at

Frequency, hFE and Capacitance range.

4. HOLD: Date Hold button, press the button, the value is held on

LCD; Press the button again, exit the hold mode and get into the

normal measuring status. Press the button more than 2 seconds,

the back light will be light up, press again the backlight turns off

or automatically turns off after 10 seconds.

5. HZ/DUTY: Frequency/Duty Circle selection button, press the

button to switch between the Frequency and Duty Circle mode at

Frequency Range; Press the button to switch to Voltage or

Current/Frequency/Duty Circle model at AC Voltage or AC

Current Range.

6. MAX/MIN: Maximum, Minimum, press the button, the instrument

5

gets into the MAX mode, the measuring maximum value will be

held at this mode; Press the button again to get into the MIN

mode, the measuring minimum value will be held at this mode. At

the MAX/MIN mode, the maximum or minimum value will be held

on LCD. Under this circumstance, there are no Bar Graph and

Auto Power Off function, hold pressing MAX/MIN button for 2

seconds, exit the MAX/MIN mode.

7. SELECT: function switch, press the button to switch the

measuring function.

8. RS232/REL: Relative Value Measurement, press the button to

the mode of Relative Value Measurement, press again to cancel

the Relative Value Measurement. Keep pressing the button more

than 2 seconds to switch to RS232 symbol appears on LCD, it

indicates the instrument is getting into the status of data

transmission. Keeping pressing the button more than 2 seconds,

RS232 symbol disappears, the data transmission is stopped.

9. Function/range selection knob: select the measuring function

and range.

10. 10A current input terminal: Measuring AC/DC 10A positive input

terminal, insert red test lead.

11. mA input terminal: Measuring AC/DC uA/mA and Temperature

positive input terminal. The hFE input terminal.

12. COM input terminal: Temperature negative input terminal,and

hFE input terminal, insert the black test lead.

13.

input terminal: measure Voltage, Frequency/Duty Circle,

Resistance, Capacitance, Diode and Continuity positive input

terminal, insert the red test lead

6

Property

General Feature

1-1 Display: LCD

1-2 Max Display: 5999 (3 5/6) counts automatic polarity display and

unit display.

1-3 Measuring method: dual-integral A/D converter

1-4 Sampling rage: 3 times/second

1-5 Over range indication: display “OL”

1-6 Low battery indication: “

1-7 Operation environment: 0~40˚C relative humidity <80%

1-8 Storage environment: -10~50˚C relative humidity <80%

1-9 Power: 2pcs 1.5V batteries (AAA battery)

1-10 Dimension: 185mm x 92mm x 48mm

1-11 Weight: Approx. 390g (including batteries)

Technic Property

1. Accuracy: (a% × reading + digits) at 23 ± 5˚C , relative humidity

<75%.

2. One year calibration guarantee since the time dispatched from

the factory.

DC Voltage (DCV)

1. Turn the function/range selection knob to DCV/ACV. Insert the
red and black test lead separately to VΩHz and COM input terminal,
press “SELECT” button to switch to DCV measurement mode.

2. The instrument was preset as the Auto Range mode of DCV
measurement, display “AUTO” symbol on LCD, press “RANGE”
button to switch to the Manual Range mode.

3. Connect the test lead to the tested circuit in parallel, the polarity
of the red test lead and the tested voltage value will be displayed on
LCD simultaneously.

” appearance

7

Note:

a) Do not measure the voltage higher than DC 1000V or AC 750V.
b) When measuring the high voltage, caution to avoid electric shock.
Cut the connection between the test lead and tested circuit at once
after measurement.
C) At the Manual Range mode, if “OL” is displayed on LCD, it
indicates the tested voltage value has exceeded the present range
limit, please select the higher range to complete the measurement

Range Accuracy Resolution

600mV 0.1mV

6V 1mV

60V 10mV

600V

1000V ±(1.0%+6d) 1V

Input impedance: >60MΩ at Range
600mV , 10MΩ at other range.
Overload protection: 1000V DC or 750V AC peak value.

±(0.5%+4d)

100mV

AC Voltage (ACV)

1. Turn the function/range selection knob to ACV/DCV, press
“SELECT” button to switch to ACV measurement mode. Insert the
red and black test lead separately to VΩHz and COM input terminal,
displayed as the following picture.

2. The instrument was preset as the Auto Range mode, displays
“AUTO” symbol on LCD, press “RANGE” button to switch to the
Manual Range mode. Press “Hz/DUTY” button to measure
Frequency/Duty Circle at the Auto Range or Manual Range mode.
But the frequency response is very low, at this time, it suits to
measure the circuit of high voltage and low frequency under the
circumstance of magnetic disturbance, such as
220V/50Hz-400Hz,380V/50Hz~400Hz.

3. Connect the test lead to the tested circuit in parallel,the polarity of

8

the red test lead and the tested voltage value will be displayed on
LCD simultaneously

Note:
a) Do not measure the voltage higher than DC 1000V or AC 750V.
b) When measuring the high voltage, caution to avoid electric shock.
Cut the connection between the test lead and tested circuit at once
after measurement.
C) At the Manual Range mode, if “OL” is displayed on LCD, it
indicates the tested voltage value has exceeded the present range
limit, please select the higher range to complete the measurement

Range Accuracy Resolution

6V 1mV

60V 10mV

600V

750V ±(1.0%+10d) 1V

Input impedance: 10MΩ. Overload
protection : 1000V DC or 750V AC peak
value.
Frequency response: 40-400Hz. Indication: average value
response (RMS of sine wave).
Duty Circle indication (0.1%~99.9%)

±(0.8%+10d)

100mV

DC Current (DCA)

1. Insert the black test lead to “COM” input terminal and the red test
lead to “mA ”or “10A”, displayed as the picture.

2. Turn the function/range selection knob to current range, press
“SELECT”, switch to DC measurement mode, then connect the test
lead with the tested circuit in series, the polarity of the red test lead
and the tested current value will be displayed on LCD
simultaneously.

9

3. At the Manual Range mode,if “OL” is displayed on LCD, it
indicates the test current value has
exceeded the present range limit, please select the higher range
to complete the measurement.

Note:

a) Do not measure the current higher than 10A at Range 10A and

higher than 6000uA at uA Range and higher than 600mA at mA

Range, otherwise the fuse will be burnt out or the instrument will be

damaged.

b) Do not connect the test lead to any circuit in parallel when the

test lead is inserted in the current input terminal, otherwise it is

possible to damage the instrument or endanger the safety of the

users. Cut the connection between the test lead and tested circuit at

once after measurement.

Range Accuracy Resolution

600uA 0.1μA

6000uA 1μA

60mA 10μA

600mA

6A 1mA

10A

±(1.0%+10d)

±(1.2%+10d)

100μA

10mA

10

Max input current: 10A (less than 15 seconds).

Overload protection: 0.5A/250V fuse, 10A/250V fuse.

AC Current (ACA)

1. Insert the black test lead to “COM” input terminal and the red test

lead to “mA ”or “10A”input terminal,displayed as the picture.

2. Turn the function/range selection knob to current range, press

“SELECT”, switch to AC measurement mode, then connect the test

lead to the tested circuit in series, the polarity of

the red test lead and the tested current value will be displayed on

LCD simultaneously

3. At the Manual Range mode,if “OL” is displayed on LCD, it

indicates the tested current value has exceeded the present range

limit, please select the higher range to complete the measurement.

Note:

a) Do not measure the current higher than 10A at Range 10A and

higher than 6000uA at uA Range and higher than 600mA at mA

Range, otherwise the fuse will be burnt out or the instrument will be

damaged.

b) Do not connect the test lead to any circuit in parallel when the

test lead is inserted in the current input terminal, otherwise it is

possible to damage the instrument or endanger the safety of the

users. Cut the connection between the test lead and tested circuit at

once after measurement.

11

Range Accuracy Resolution

600uA 0.1μA

6000uA 1μA

60mA 10μA

600mA

6A 1mA
10A

Max input current : 10A (less than 15 seconds). Frequency

response: 40-100Hz

Overload protection:0.5A/250V fuse, 10A/250V fuse. Duty Circle

Indication: (0.1%-99.9%)

±(1.5%+10d)

±(2.0%+15d)

100μA

10mA

Resistance (Ω)

1. Turn the function/range selection knob to Ω, insert the red and

black test lead separately to VΩHz and COM input terminal.

2. Connect the test lead to the tested resistance in parallel, the

tested resistance value will be displayed on LCD

3. Auto Range mode is preset when turning on, press “RANGE”

button to switch to Manual Range mode.

12

4. At the Manual Range mode,if “OL” is displayed on LCD, it

indicates the tested resistance

value has exceeded the present range limit, please select the

higher range to complete the measurement.

Note:

a) When measuring the in-circuit resistance, Make sure all the

power of the tested circuit has been turned off and all capacitors are

fully discharged.

b) It will cause the reading incorrect to input any voltage when

measuring the resistance. If the voltage exceeds 250V, over-range

protection voltage, it is possible to damage the instrument and

endanger the safety of the users.

c) At Range 600Ω, short-circuit the test lead to measure the wire

resistance, and then subtract it from the real measurement.

Range Accuracy Resolution

600Ω ±(0.8%+5d) 0.1Ω
6KΩ 1Ω
60KΩ 10Ω
600KΩ 100Ω
6MΩ
60MΩ ±(1.2%+10d) 10KΩ

±(0.8%+4d)

1KΩ

13