M0320 - Multimeter Emos - Free user manual and instructions

Product Type	Digital Multimeter
Model	M0320 (MD-110)
Brand	Emos
Display	LCD, 3.5 digits (1999 counts)
Measurement Category	CAT III 300 V
DC Voltage Ranges	200 mV, 2000 mV, 20 V, 200 V, 300 V
AC Voltage Ranges	200 V, 300 V (40-400 Hz)
DC Current Ranges	2000 μA, 20 mA, 200 mA
Resistance Ranges	200 Ω, 2000 Ω, 20 kΩ, 200 kΩ, 2000 kΩ
Diode Test	Yes
Battery Test	1.5 V and 9 V
Signal Generator	50 Hz rectangular, >3 Vpp
Dimensions	57 × 95 × 30 mm
Weight	82 g (including battery)
Power Supply	12 V battery, type 23A
Overload Protection	250 mA/300 V safety fuse (5×20 mm)
Auto Power Off	Yes
Low Battery Indication	Battery symbol on display
Over Range Indication	Display shows "1"
Operating Temperature	0 °C to 40 °C, humidity <75%
Storage Temperature	-10 °C to 50 °C, humidity <85%
Maintenance	Clean with damp cloth and mild detergent; avoid solvents
Safety Standards	IEC-61010, double insulation
Warranty	2 years (excluding battery and fuse)

Frequently Asked Questions - M0320 Emos

What is the maximum voltage I can measure with the Emos M0320 multimeter?

The maximum voltage is 300 V for both AC and DC, with a category rating of CAT III 300 V. Do not exceed this limit to avoid electric shock or damage.

How do I measure DC current with the M0320?

Set the rotary switch to the A position, select the appropriate range (2000 μA, 20 mA, or 200 mA), connect the probes in series with the circuit, and turn on power. Always start with the highest range if unknown. Do not exceed 200 mA.

How do I replace the battery in the M0320?

Disconnect the test leads from any circuit. Unscrew the back cover, remove the old 12V (type 23A) battery, insert a new one, and replace the cover. The low battery symbol indicates when replacement is needed.

What does the '1' on the display mean?

A '1' on the display indicates an over-range condition, meaning the measured value exceeds the selected range. Switch to a higher range to get a proper reading.

How do I test a diode with the M0320?

Set the rotary switch to the diode symbol (➤). Connect the red probe to the anode and black to the cathode. The display shows the forward voltage drop (approx. 2.8 V open circuit). A reading of '1' indicates a faulty connection or open circuit.

Can I measure resistance in a live circuit?

No, always disconnect the circuit from power and discharge capacitors before measuring resistance to avoid damage to the multimeter or electric shock.

How do I replace the safety fuse in the M0320?

Disconnect the test leads. Unscrew the back cover, locate the blown fuse (F 250 mA/300 V, 5×20 mm), replace it with an identical fuse, and screw the cover back on. Use only the specified fuse type.

What is the auto power off feature?

The multimeter automatically turns off after a period of inactivity to conserve battery life. To turn it back on, rotate the rotary switch to OFF and then to the desired function.

How should I clean and maintain the M0320?

Clean the exterior with a damp cloth and mild detergent only when the device is off and disconnected. Do not use solvents or abrasives. Store in a dry, cool place away from strong magnetic fields.

What is the warranty period for the M0320?

The multimeter has a 2-year warranty covering material and workmanship defects. The battery and safety fuse are not covered. Damage from improper use or extreme conditions voids the warranty.

USER MANUAL M0320 Emos

Before you start using MD-110 read carefully this manual.

Especially important passages that deal with principles of safety work with this device are highlighted. You will prevent electric shock or damage of the device. The digital multimeter was designed in accordance with standard IEC-61010 relating to electronic measuring instruments falling in to the category (CAT III 300 V), pollution level 2. The CAT III category is used to measure circuits powered by a fixed output power supply, such as a relay, socket, switchboards, power supplies, short branching circuits and lighting systems in large buildings.

Electrical symbols

Alternating current (AC)

Direct current (DC)

Alternating/direct current (AC/DC)

WARNING – Read up the instructions before using this device

Risk of electric shock

Ground

Safety-fuse

Declaration of Conformity (CE)

The device is protected by a double insulation and a reinforced insulation

Pay special attention to the following instructions:

• Carefully check that the device is not damaged before you start using the multimeter. If you see any obvious damage of the device, do not perform any measurement! Check if the surface of the multimeter is not scratched and side connections are not unglued.
• Check the insulation of the measuring probes and jaws. There is a risk of electric shock when the insulation is damaged. Do not use the damaged probes!
• Do not measure voltages higher than 300 V or current higher than 200 mA!

- Do not measure current, if the void voltage in an open circuit is higher than 300 V.

- The „COM“ terminal must always be connected to the reference measuring ground.

- If you detect abnormal measurement results, do not use the multimeter. If you are not sure about the cause of a failure, contact the service center.

- Do not measure higher voltages and currents than those indicated on the front panel of the multimeter. There is a risk of electric shock and damage of the multimeter!

- Verify that the multimeter is working properly before use. Test a circuit where you know its electrical parameters.

- Turn off the power supply of the circuit before you connect the multimeter to the circuit of which current you intend to measure to.

- Do not use or store the multimeter in environments with high temperature, dust and moisture. It is also not recommended to use the device in an environment where a strong magnetic field is present or where there is a risk of explosion or a fire.

- When replacing the battery or other parts of the multimeter, use spare parts of the same type and specification. Replace the parts only when the multimeter is switched off and disconnected!

- Do not change or modify the internal circuits of the multimeter!

- Caution when measuring voltages higher than 30 V AC rms, 42 V peak or 60 V DC. Risk of electric shock!

- When handling the measuring pins make sure to hold them behind the finger barrier.

- To avoid electric shock, do not touch any bare wires with your hands or skin.

- Disconnect the measuring pins from the circuit before opening the cover of the multimeter.

- Do not take any measurements if the cover of the multimeter is removed or it is loose.

- When the display shows a discharged battery icon „—+“, replace the battery. Otherwise, the subsequently performed measurements can be inaccurate. This can lead to biased results of the measurement resulting in an electric shock!

WARNING

Use a multimeter MD-110 only as specified below, otherwise it may result in damage of the device or your health. Pay attention to the following instructions:

- Disconnect circuits from their power source and discharge high-voltage capacitors, before you make any measurement of resistance, diode or current.

- Check if a round range selector switch knob is in the correct position before measurement. Do not make any changes in the measuring range (by turning the round range selector switch knob) during the measurement in any case! This could cause damage of the device.

- When measuring current, turn off the power supply of circuit before you connect the multimeter.

Description of the device

Digital multimeter MD-110 belongs to a series of compact devices with 3.5 digital display, designed to measure AC and DC voltage, DC current, resistance and diode testing. It indicates exceeding of the measured range. It has an auto power off feature. The multimeter offers an overload protection and information about low battery. Ideal use of the multimeter MD-110 is for example in workshops, laboratories and homes.

Technical specifications

Display: LCD, 1999 (3.5 digits) with an automatic polarity indication

Working temperature: 0 °C to 40 °C < 75 %

Storage temperature: -10 °C to 50 °C, relative humidity < 85 %

Low battery: indication by battery symbol on the display

Over range indication: display number "1" on the LCD

Measurement category: CAT III (300 V)

Dimensions and weight: 57 × 95 × 30 mm, 82 g (including battery)

Front view of the multimeter

1. Display - 3.5 digit LCD display with maximum indication up to 1999
2. Rotary switch knob

It is used for the desired function selection and also for turning the measuring device on and off. Set the rotary switch knob to the OFF position, when you are not using the device.

1. Test conductors

Measurement accuracy

Accuracy is specified for a period of one year after calibration, at 18 °C to 28 °C and at a relative humidity of 75 %.

Accuracy specification has the following form:

±([% of device reading] + [number of the lowest valid digits])

DC voltage (DC)

Range Resolution Accuracy
200 mV 100 μV	±(0.5 % + 5)
2000 mV 1 mV		±(0.8 % + 5)20 V 10 mV
200 V 100 mV
300 V 1 V ±(1 % + 5)

Input impedance: 1 MΩ

⚠️ Maximum allowable voltage input: 300 V

Alternating voltage (AC)

Range Resolution Accuracy
200 V 100 mV	±(1.2 % + 10)
300 V 1 V ±(1.2 % + 10)

Input impedance: about 500 kΩ

Frequency range: 40 Hz to 400 Hz

⚠️ Maximum allowable voltage input: 300 V

Response: Average, calibrated to a virtual value of the sine wave

Direct current (DC)

Range Resolution Accuracy
2000 μA 1 μA ±(1 % + 5)
20 mA 10 μA ±(1 % + 5)
200 mA 100 μA ±(1.2 % + 5)

Over voltage protection: 250 mA/300 V safety fuse

Resistance

Range Resolution Accuracy
200 Ω 0.1 Ω ±(1 % + 5)
2000 Ω 1 Ω		±(0.8 % + 5)20 kΩ 10 Ω
200 kΩ 100 Ω
2000 kΩ 1 kΩ ±(1.2 % + 5)

Max. open circuit Voltage: about 3 V

Battery Test

Range Function Note
1.5 V	Will display a voltage current over the 45 battery	Test current: about 20 mA
9 V Test current over the 45 battery

Diode Test

Range	Resolution	Accuracy
	1 mV	Displays an approximate drop of voltage in a forward direction of the diode.Voltage during open circuit: approximately 2.8 VTest current: approximately 1 mA

Generator of a rectangular output signal

The frequency of the output signal: 50 Hz

Level: higher than 3 Vpp

Measurement of direct current (DC) voltage

1. Set the rotary switch knob to the V position.
2. Select the measuring range. In case you do not know the voltage range in advance, set the highest range and reduce it gradually after every measurement.
3. Attach the measuring pins to a device or circuit, where you measure the DC voltage.
4. Turn on the power supply of the device that you measure. The display displays the voltage and polarity relative to the red measuring tip.

Note:

⚠ To avoid electric shock or damage of the measuring device do not connect voltages higher than 300 V.

Measurement of alternating current (AC) voltage

1. Set the rotary switch knob to the ∨ position.
2. Select the measuring range – In case you do not know the voltage range in advance, set the highest range and reduce it gradually after every measurement.
3. Attach the measuring pins to a device or circuit, where you measure the AC voltage.
4. Turn on the power supply of the device that you measure. The display displays the voltage and polarity relative to the red measuring tip.

To avoid electric shock or damage of the measuring device do not connect voltages higher than 300 V.

Measurement of DC current

1. Set the rotary switch knob to the A position.
2. Select the measuring range – In case you do not know the current range in advance, set the highest range and reduce it gradually after every measurement.
3. Attach the measuring pins to a device or circuit, where you measure the DC.
4. Turn on the power supply of the device that you measure. The display displays the current value and polarity relative to the red measuring tip.

Resistance Measurements

1. Set the rotary switch knob to the position.
2. Select the measuring range – In case you do not know the value of the measured resistance in advance, set the highest range and reduce it gradually after every measurement.
3. Attach the measuring pins to a measured device.
4. The measured value is displayed on the display.

Note: If you measure a value higher than 1 MΩ, it is normal that the measured value of the resistor stabilizes after a few seconds. If the circuit is not closed, the display will show "1".

⚠️ Disconnect circuit from its power source and discharge high-voltage capacitors before measurement.

Diode Test

This mode can be used for diodes, transistors and other semiconductor components inspection.

1. Set the rotary switch knob to the ➤ position.
2. Attach the red measuring pin to the anode of a measured diode and the black measuring pin to the cathode. The display shows the voltage of the diode in the forward direction. The display shows "1" if the connection is bad.

To avoid damage of the multimeter or the measured devices, disconnect circuit from its power source and discharge all high-voltage capacitors before the diode measurement. Disconnect the measured device or circuit from the measuring leads after measurement.

Battery Test

1. Set the rotary switch knob to the position for battery testing 1.5 V or 9 V.

2. Attach the measuring pins to the battery with the red pin connected to the positive pole and the black tip to the negative pole of the battery.

3. The measured value is displayed on the display.

Note: Disconnect the test pins from the battery after measurement.

Generator of a rectangular output signal (voltage)

1. Set the rotary switch knob to the N position.
2. Attach the measuring pins to the tested device.
3. The measured value is displayed on the display.

To avoid damage of the multimeter or the measured devices, do not attempt to reach voltage higher than 10 V. The short circuit protection is not active during this function.

Note:

The frequency of the output signal: 50 Hz

Level: higher than 3 Vpp during load of 1 MΩ

⚠️ Battery replacement

Before replacing the battery the measuring pins must be disconnected from of the circuit or a device. If the low battery symbol is displayed on the display ( ), it is necessary to replace the battery as soon as possible.

1. Unscrew the screws with a suitable screwdriver on the backside of the multimeter and remove the cover.
2. Remove the old battery and replace it with a new one with a specified dimension (12 V, type 23 A).
3. Put the cover on and screw it back.

Safety fuse replacement

Before replacing the safety fuse the measuring pins must be disconnected from of the circuit or device. The safety fuse blows usually if the prescribed measurement procedure is not followed down.

1. Unscrew the screws with a suitable screwdriver on the backside of the multimeter and remove the cover.
2. Remove the blown safety fuse and replace it with a new one with a specified dimension (F 250 mA/300 V AC fuse, 5 × 20 mm).
3. Put the cover on and screw it back.

Note: For a constant overload protection use a safety fuse with a specified current and voltage.

Maintenance instructions of the multimeter

Warning

• Do not attempt to repair the multimeter or modify it in any way, if you are not qualified to execute such an activity and if you do not have the appropriate calibration devices.
• To prevent electric shock, ensure that no liquid water enters the interior of the multimeter!

• Disconnect the measuring pins from the circuit before opening the cover of the multimeter.

• Clean the body of the multimeter regularly with a damp cloth and a mild detergent. Cleaning should be done only when the multimeter is switched off and disconnected.

• Do not use solvents or abrasives for cleaning!
• If you are not using the multimeter for a long time, turn it off and remove the battery.
• Do not store the multimeter in a place where there is a high humidity and temperature, or in the environment with a strong magnetic field!
• When replacing the safety fuse, make sure a new fuse is of the same type and the same range as the original one. Safety fuse: (F 250 mA/300 V), type F, ∅ 5 × 20 mm.

The purchased device is under a warranty concerning a material quality and multimeter workmanship. This warranty is valid for two years. The warranty does not include a battery and a safety fuse. A complaint will not be accepted if the defect of the device is caused by its improper use or exposure to extreme conditions.

Information on the backside of the multimeter:

Warning

Read all instructions before using this device. To prevent a possible electric shock, disconnect the measuring leads from the power supply before opening the multimeter.

This device is not intended for use by a person (including children) whom a reduced physical, sense or mental inability or a lack of experience and knowledge inhibits from a safe using of the device, if they are not supervised or have been instructed about the use of the device by a person responsible for their safety. It is necessary to supervise children to ensure that they do not 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.

EMOS spol. s r.o. declares that the MD-110 is in compliance with the essential requirements and other relevant provisions of Directive. The device can be freely operated in the EU. The Declaration of Conformity can be found at http://www.emos.eu/download.

Technical assistance can be obtained from the supplier:

current continuu (DC)

current alternativ/continuu (AC/DC)