EMOS M0391 Digital Multimeter User Guide

: June 10, 2024
: EMOS

EMOS M0391 Digital Multimeter

M0391 Digital Multimeter

Overview

Before you begin using multimeter MD-210, read this instruction manual thoroughly. It contains
particularly important passages concerning occupational safety principles when using the device. Such passages are highlighted. Reading the manual will prevent potential injury by electric current or damage to the device.
The multimeter was designed in accordance with the
IEC-61010 standard regarding electronic measuring devices in the category (CAT III 300 V), for 2nd pollution degree.
Category CAT III is designed for measuring circuits powered by a fixed output power supply, such as relays, sockets, switchboards, power supplies, short branching circuits and lighting systems in large buildings

alternating current (AC)
direct current (DC)
direct and alternating current (AC/DC)
earthing
double insulation
low battery
diode
fuse
warning
risk of injury by electric current
product complies with applicable EU standards
This symbol means: warning, risk of danger.
Read the manual in all cases where this symbol is used!
This symbol indicates risk of injury by electric current.

ATTENTION

Comply with the following instructions in particular:

Make sure the device is not damaged before you begin using the multimeter. If you find obvious signs of damage on the body of the device, do not make any measurements! Check that the surface of the multimeter does not have scratches and that the side joints are not coming apart.
Do not measure voltage higher than 300 V, or current higher than 10 A!
The COM terminal must always be connected to reference ground.
Also check the measuring tips. Insulation on the measuring probes should have no visible signs of damage. Damaged insulation may result in injury by electric current. Therefore, do not use damaged measuring probes.
If you find that the multimeter is making abnormal measurements, stop using it. These may be caused by a disrupted fuse. If you are unsure of the cause of the defect, contact a service centre.
Do not use or store the multimeter in environments with high temperature, dust or humidity.
It is also not recommended to use the device in environments with potentially strong magnetic fields or risk of explosion or fire.
Do not measure voltages and currents higher than indicated on the front panel of the multimeter. Risk of injury by electric current or damage to the multimeter!
Check that the multimeter is working properly before use. Test on a circuit with known electrical values.
Before you connect the multimeter to a circuit you intend to measure, turn off the power to the circuit.
If you need to replace a component of the multimeter (e.g. battery, fuse), always use spare parts of the same type and specifications. Change parts only when the multimeter is disconnected and turned off.
Do not alter or otherwise interfere with the internal circuitry of the multimeter!
Be extra careful when measuring voltages higher than 30 V AC rms, 42 V peak or 60 V DC. Risk of injury by electric current!
When using measuring tips, make sure you are holding them behind the finger barriers.
Disconnect the measuring tips from the tested circuit before opening the casing of the multimeter.
Do not perform measurements if the multimeter‘s casing is removed or loose.
Change the battery once the low battery warning indicator appears on the screen.
Otherwise, subsequent measurements may be inaccurate. Incorrect measurements may then result in injuries by electric current!

ATTENTION
Use multimeter MD-210 only in the manner specified below. Otherwise, the device could get damaged or the user may suffer injury. Comply with the following instructions:
Before measuring resistance, diodes or current, disconnect the circuits from the power supply and discharge the high-voltage capacitors.
Before measuring, make sure the circular switch for measuring range is in the correct position. Under no circumstances should you make any changes to the measuring range (by moving the circular switch for measuring programs) while measuring. Doing so could damage the device.
If you intend to measure current, check the multimeter‘s fuse and turn off the power supply to the circuit before you connect the multimeter.
When you are measuring, first connect the black conductor (probe) and then the red conductor (probe). When disconnecting the testing conductors, disconnect the red one first.

Maintenance Instructions

Attention
Do not attempt to repair or modify the multimeter in any way if you are not qualified for the task or do not have access to the necessary calibration equipment.
To prevent injury by electric current, make sure that water does not enter the inside of the multimeter!

Disconnect the measuring tips from the tested circuit before opening the casing of the multimeter.
Regularly clean the body of the multimeter with a moist cloth and a mild detergent. Perform cleaning only when the multimeter is disconnected and turned off.
Do not use solvents or abrasive agents for cleaning!
If you are not using the multimeter for an extended period of time, turn it off and remove the batteries.
Do not store the multimeter in places with high humidity and temperature or in places with a strong magnetic field!

Device Description

Multimeter MD-210 is a compact device with a 3.5 digit display. It is designed for measuring direct and alternating voltage, direct and alternating current, resistance, temperature, test diodes and perform audio testing of conductivity and of circuits. The multimeter provides protection against overload and informs the user when the battery is low. It is ideal for use in e.g. workshops, laboratories and households.

Front View of the Multimeter

Screen – displays 3.5 digits i.e. a maximum value of 1999
Function and range switch – allows selecting functions and the desired range as well as turning the multimeter on or off. If you are not using the multimeter, turn it off. The battery will then last you longer.
10 A socket – used for connecting the plug of the red (positive) tipped measuring conductor to measure currents in 10 A DC current range.
socket – used for connecting the plug of the red (positive) tipped measuring conductor to measure voltage, resistance or current to up to 200 mA.
COM socket – used for connecting the plug of the red (positive) tipped measuring conductor.

Specifications

Screen: LCD, 1999 (3.5 digits) with automatic polarity indication
Measuring method: dual-slope integration via an A/D converter
Reading frequency: 2–3× per second
Operating temperature and humidity: 0 °C to 40 °C, <75 %
Storage temperature and humidity: -10 °C to 50 °C, relative humidity <85 %
Power supply: 1× 9 V (6F22) battery
Fuses: F 250 mA/300 V, ø 5×20 mm, F 10 A/300 V, ø 5×20 mm
Low battery : indication via a battery symbol on the screen
Indication of exceeded range: shows „OL“ on the LCD
Measuring category: CAT III (300 V)
Enclosure: IP20 Dimensions 28 × 138 × 70 mm
Weight: 141 g (battery included)

Accuracy

The stated accuracy is for a period of one year since calibration of the device at 18 °C to 28 °C and relative humidity of up to 75 %.
Measurement accuracy is stated as: ± [(% of reading) + (lowest valid digits)].

DC Voltage

Range

| Resolution| Accuracy
---|---|---
200 mV| 100 µV|

±(0.5 % + 5)

2 V

| 1 mV|

±(0.8 % + 5)

20 V

| 10 mV
200 V|

100 mV

300 V| 1 V| ±(1 % + 5)

Input impedance: 1 MΩ
Maximum input voltage: 300 V DC

AC Voltage

Range

| Resolution| Accuracy
---|---|---
200 V| 100 mV|

±(1.2 % + 10)

300 V

|

1 V

Frequency range: 40 Hz to 400 Hz
Maximum input voltage: 300 V AC
Note: The value is an average corresponding to the calibrated effective sine wave.

Direct current (DC)

Range

| Resolution| Accuracy
---|---|---

20 µA

| 0.01 µA|

±(1.2 % + 5)

200 µA|

0.1 µA

|

±(1 % + 5)

2 000 µA

|

1 µA

20 mA

|

10 µA

200 mA

| 100 µA| ±(1.2 % + 5)
10 A| 10 mA|

±(2 % + 5)

Overload protection:
µA and mA range: F 250 mA/300 V fuse
10 A range: F 10 A/300 V fuse

Maximum input current:

socket: max. 200 mA
10 A socket: max. 10 A
When measuring currents larger than 2 A: measurement duration must be max. 10 seconds and measurement may only be repeated again after 15 minutes!

Resistance

Range

| Resolution| Accuracy
---|---|---
200 Ω| 0.1 Ω|

±(1.2 % + 5)

2 kΩ

| 1 Ω
20 kΩ|

10 Ω

200 kΩ

| 100 Ω
2 MΩ|

1 kΩ

Voltage of an open circuit: max. 1 V
Diode and Circuit Continuity Test

Range	Description	Note
The approximate voltage of the diode in the direction of the current flow
will appear on the screen.

Voltage without load: 2.2 V

| Built-in buzzer indicates that resistance in the circuit is lower than 20 Ω. If resistance is between 20 Ω and 150 Ω the buzzer may or may not sound.
If resistance is higher than
150 Ω, the buzzer will not sound.| Voltage without load: 2.2 V

Measuring Direct Voltage

Connect the plug of the red measuring conductor into the socket and the black conductor into the COM socket.
Turn the circular switch to function marked
Choose a measuring range and place the measuring tips the spot or circuit where you wish to measure DC voltage.
If you do not know the voltage range beforehand, set the highest possible range and gradually decrease it as you measure.
Turn on the device you want to measure. The screen will display the voltage value and polarity relative to the red measuring tip.
If you exceed the range of 300 V, immediately stop measuring. Otherwise, you risk damaging the multimeter and suffering injury by electric current.

Measuring Alternating Voltage

Connect the plug of the red measuring conductor into the socket and the black conductor into the COM socket.
Turn the circular switch to function marked . Choose a measuring range and place the measuring tips the spot or circuit where you wish to measure AC voltage.
If you do not know the voltage range beforehand, set the largest possible range and gradually decrease it as you measure.
Turn on the device you want to measure. The screen will display the voltage value and polarity relative to the red measuring tip.
If you exceed the range of 300 V, immediately stop measuring. Otherwise, you risk damaging the multimeter and suffering injury by electric current.

Measuring Direct Current

Connect the plug of the red measuring conductor into the socket and the black conductor into the COM socket. If the measured voltage is between 200 mA and 10 A, connect the plug of the red measuring conductor into the 10 A socket.
Turn the circular switch to function marked .
Connect the multimeter serially to the circuit you wish to measure and turn on the power supply to the measured device.
The screen will display the measured current and polarity relative to the red measuring tip.

Never use the device to measure current in places where the idle voltage in an open circuit exceeds 300 V.
Measuring current at higher idle voltage could result in damage to the device (fuse burnout, electric discharge) or injury by electric current!

Measuring Resistance

Connect the plug of the red measuring conductor into the socket and the black conductor into the COM socket.
Turn the circular switch to function marked Ω .
Select measuring range. Turn off the power supply to the circuit and discharge all high-voltage capacitors before measuring resistance in the circuit. Doing so prevents potential damaging of the multimeter.
Connect the measuring tips to the device or circuit where you wish to measure resistance.
The screen will show the measured resistance value.

Note:

When measuring resistances higher than 1 MΩ, it is necessary to wait a few seconds before the measured value stabilizes.
If the circuit is open, the ”OL” symbol will appear, same as when the measuring range is exceeded. Before measuring resistance, make sure that the measured object is disconnected from power supply and all its capacitors are fully discharged.

Diode Test

Connect the plug of the red measuring conductor into the socket and the black conductor into the COM socket.
Turn the circular switch to function marked .
Place the red measuring tip onto the diode‘s anode and then the black measuring tip onto the diode‘s cathode.
The screen will show voltage in mV for the direction of current flow. „OL“ will appear on the screen if the polarity has been reversed.

Circuit Continuity Test

Connect the plug of the red measuring conductor into the socket and the black conductor into the COM socket.
Turn the circular switch to function marked .
Connect the measuring tips to the tested circuit or device. If resistance is lower than 20 Ω, you will hear a buzzer.
Note: Before making measurements, make sure that the measured circuit is disconnected from power supply and all its capacitors are fully discharged.

Changing Batteries

If the display shows the symbol, the battery needs replacing. Use a suitable screwdriver to change the battery.
Before changing the battery, disconnect the measuring tips from the measured circuit or device and turn the switch to the OFF position.
Unscrew the rear cover.
Replace the 9 V type 6F22 battery with a new one.
Use alkaline batteries only. Do not use rechargeable batteries.
Make sure to observe the correct polarity. After changing the battery, replace the cover and screw it back on.

Replacing the Fuse

If the fuse burns out, it is most likely caused by improper handling. The multimeter uses fuses with these parameters:
F 250 mA/300 V, ø 5×20 mm, F 10 A/300 V, ø 5×20 mm.
The fuse is located under the battery cover. Always replace the fuse with a fuse of the same type and parameters. Replace the battery cover and close it shut.
To replace the F 10 A L 300 V fuse, contact a service centre.
Before changing a fuse, disconnect the measuring tips from the measured circuit or device and turn the switch to the OFF position.

This device is not intended for use by persons (including children) whose physical, sensory or mental disability or lack of experience and knowledge prevents safe use, unless they are supervised or

instructed regarding use of the appliance by a person responsible for their safety. Children must always be supervised and must never play with the device.
Do not dispose with domestic waste. Use special collection points for sorted waste.
Contact local authorities for information about collection points. If the electronic devices would be disposed on landfill, dangerous substances may reach groundwater and subsequently food chain, where it could affect human health.
You can request technical assistance from the supplier:
EMOS spol. s r.o., Lipnicka 2844, Prerov, Czech Republic