Emos MD-420, Manual

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• Be cautious when measuring voltages higher than 30 V AC
rms, 42 V peak or 60 V DC.
• Risk of injury by electric current!
• When using the measuring tips, make sure you hold them
behind the finger barriers.
• Disconnect the measuring tips from the tested circuit before
opening the multimeter’s casing.
• Do not make measurements if the casing of the multimeter
is removed or loose.
• Replace the battery once the screen shows a warning indica-
tor for low battery
• Otherwise, subsequent measurements may be inaccurate.
That may lead to false or distorted measurement results and
subsequent injury by electric current!
Warning
Use multimeter MD-420 only as specified below. Other uses
may result in damage to the device or your health. Follow these
instructions:
• Before you measure resistance, diodes or current, disconnect
circuits from power supply and discharge their high-voltage
capacitors.
• Before you make measurements, make sure the measuring
range switch is in the correct position. Do not under any
circumstances make changes to the measuring range during
measurement (by turning the circular measuring programme
switch). Doing so could damage the device.
• If you measure current, check the multimeter’s fuse and
turn off the power supply for the circuit before you connect
the multimeter.
• When making measurements, connect the black conductor
(probe) first and the red conductor (probe) second. When
disconnecting the conductors, disconnect the red one first.
Instructions for Multimeter Maintenance
Warning
Do not attempt to repair or in any way modify the multimeter if
you are not qualified for such an activity and if you do not have
the necessary calibration tools at your disposal.
To prevent injury by electric current, make sure that water does
not enter the interior of the multimeter!
• Disconnect the measuring tips from the tested circuit before
opening the multimeter’s casing.
• Regularly clean the body of the multimeter with a moist
cloth and a mild detergent. Clean only when the multimeter
is disconnected and switched off.
• Do not clean using solvents or abrasive agents!
• If you are not going to be using the multimeter for an ex-
tended period of time, turn it off and remove the batteries.
• Do not store the multimeter in a place with high humid-
ity or temperature or in an environment with a strong
magnetic field!
Device Description
The multimeter belongs to a series of compact devices that have
a 3.5 digit screen and are designed for measuring DC and AC
voltage, direct current, resistance, capacity, temperature, test
diodes and perform audible tests of conductivity and circuits.
The multimeter is able to capture and hold the maximum meas-
ured value and the displayed value on the screen. It indicates
the exceeding of the measuring range. It also has an automatic
switch-off function.
The multimeter provides protection against overload and informs
the user when the battery is low. Ideal use of the multimeter is
e.g. in workshops, laboratories and households.
Frontal View of the Multimeter
(see Fig. 1)
1 – Screen
Displays 3.5 digits and can display a maximum value of 1999.
2 – Measuring Range Switch
The multimeter has an automatic range setting if you measure
voltage, current, resistance and capacity.
In automatic range mode, AUTO appears on the screen.
To select or end manual range mode:
a. Press the RANGE button. The multimeter switches to
manual mode and the AUTO symbol disappears from
the screen. Each subsequent press of the RANGE button
increases the range. After reaching maximum range, the
switch loops back to the lowest range.
b. To end manual mode, press and hold the RANGE but-
ton for 2 seconds. The multimeter will switch back to
automatic mode and the word AUTO will appear on
the screen.
3 – FUNC Button
When measuring current, you can use the FUNC button to switch
between AC and DC measurement.
When measuring temperature, the FUNC button switches be-
tween °C and °F units.
The FUNC button also switches between measuring diodes or
performing conductivity tests on circuits.
4 – On/Off Switch
Pressing switches the device on or off.
5 – Range and Function Switch
The switch is used for selecting the desired function and range.
6 – “10 A” Socket
Plug in the head of the red (positive) tipped measuring conductor
to measure current in the 10 A AC/DC current range.
7 – “COM” Socket
Plug in the head of the black (negative) tipped measuring
conductor.
8 – “INPUT” Socket
Plug in the head of the red (positive) tipped measuring conduc-
tor to measure voltage, resistance, capacity or current to up
to 200 mA.
9 – Screen Backlight Button
Holding the button for 2 seconds illuminates the screen. Back-
lighting will turn off automatically after 15 seconds, or can be
switched off manually by again holding the button for 2 seconds.
10 – Button
Pressing the button will hold the measured value on the screen,
indicated by the symbol. Another press of the button
cancels the function and the symbol disappears.
11 – Button
Pressing the button will automatically hold the highest measured
value and the symbol will appear on the screen. Another
press of the button cancels the function and the symbol dis-
appears. In some ranges, the maximum value function is not
available.
Specifications
Screen: LCD, 1999 (3.5 digits) with automatic polarity indication
Measurement method: double down-slope integral A/D
conversion
Reading speed: 2–3× per second
Operating temperature: 0 °C to 40 °C <75 %
Storage temperature: -10 °C to 50 °C, relative humidity <85 %
Temperature measurement range: -20 °C to 1 000 °C (-20 °C to
250 °C with the enclosed temperature probe)
Power supply: 3× 1.5 V AAA batteries
Fuses: F 250 mA/300 V, ø 5×20 mm, F 10 A/300 V, ø 5×20 mm
Low battery: indication by battery symbol on the screen
Indication of exceeded range: displays “OL” on the LCD