Limit DM 620 Multimeter Instruction Manual

Limit DM 620 Multimeter

Product Information

The Multimeter Limit DM 620 is a versatile and reliable measuring tool designed to meet the highest safety standards. It complies with CE standards including EN 61010-1:2010+A1:2019, EN 61010-2-030: 2010, EN 61010-2-033:2012, EN 61326:2013, EN61326-2-2:2013. It also adheres to CAT III: 1000 V, CAT IV: 600 V safety certifications, as well as RoHS, pollution grade II, and double insulation standards.

Features

• Safety certification: CE standards, CAT III: 1000 V, CAT IV: 600 V
• Analog bar display for easy visualization
• High refresh rate for accurate measurements
• Voltage measurement range (DC)
• Voltage measurement range (AC)
• Capacitance measurement range
• Temperature measurement range
• Current measurement range (AC)
• Current measurement range (DC)
• Resistance measurement range
• Frequency measurement range
• Duty ratio measurement range
• Operating temperature range
• Storage temperature range

SAFETY INFORMATION

Safety certification

This Meter strictly follows the CE standards: EN 61010-1:2010+A1:2019, EN 61010-2-030: 2010, EN 61010- 2-033:2012, EN 61326:2013, EN61326-2-2:2013, as well as CAT III: 1000 V, CAT IV: 600 V, RoHS, pollution grade II and double insulation standards.

To prevent possible electrical shock, fire, or personal injury

1. Do not use the Meter if it is damaged or if the Meter is not operating properly. Inspect the case before using the Meter and look for cracks or missing plastic. Pay attention to the insulation layers.
2. If the test leads are damaged, they must be replaced with leads of the same type or the same electrical specification.
3. When measuring, do not touch exposed wires, connectors, unused inputs, or the circuit being measured.
4. When measuring a voltage higher than AC 30 V RMS, 42 V peak or DC 60 V, keep your fingers behind the finger guard on the test lead to prevent electric shock.
5. If the range of the voltage to be measured is unknown, the maximum range should be selected and then gradually decreased.
6. Never apply more than the rated voltage and current, as marked on the Meter.
7. Before switching ranges, make sure to disconnect the test leads from the circuit to be tested. It is strictly prohibited to switch range during the measurement.
8. Before measuring resistance, testing diodes, continuity, or capacitance, switch off the power supply to the circuit and fully discharge all capacitors.
9. Do not use or store the Meter in high temperature, high humidity, flammable, explosive or strong magnetic field environments.
10. To avoid the damage to the Meter and to users, do not modify the internal circuitry of the Meter.
11. To avoid false readings, replace the battery as soon as the battery indicator appears.
12. Maintenance and servicing must be carried out by qualified professionals or designated departments.
13. The warranty does not apply to damage caused by accident, negligence, misuse, modification, contamination or mishandling.

OVERVIEW

The Limit multimeter 620 is a handheld true RMS digital multimeter with high reliability and security (6000 counts). With its large screen, high-resolution display, full-scale overload protection, and unique design, it is a new and highly practical electrical multimeter. The meter can measure AC/DC voltage/ current, resistance, continuity, capacitance, frequency, duty ratio, temperature and be used to test diodes, etc. Featuring data transmission, data hold, relative value measurement, peak measurement, internal temperature alarm, low battery indication, backlight, auto power off, and non-contact voltage detection (NCV) functions, the meter is ideal for many applications.

FEATURES

• LCD with 20 mm digits and backlight
• NCV function
• AC/DC voltage measurement
• AC/DC current measurement
• Resistance measurement
• Continuity/Diode test
• Capacitance measurement
• Data hold
• Frequency and duty ratio measurement
• Temperature test °C or °F
• Data transmission via USB

SPECIFICATIONS

≤50% at 30 ~ 40°C

Operating altitude| ≤2000 m
Dimensions (L × W × D)| 186 × 89 × 49 mm
Power supply| 1.5 V AAA × 4 (included)
Weight| 400 g (with batteries)

POSITIONS (P 1 & P 2)

1. NCV detector
2. Indicator light
3. LCD display
4. Function buttons
5. Function dial
6. Input terminals
7. USB (Bluetooth) access port
8. Test lead slots
9. Nut for external holder
10. Battery compartment fixing screw
11. Tilt stand

ACCESSORIES

Open the packaging box and take out the meter. Please double check whether the following items are missing or damaged, contact your supplier immediately if they are.

1. User manual—————————————— 1 pc
2. Test leads——————————————– 1 pair
3. Adapter socket————————————– 1 pc
4. K-type thermocouple——————————- 1 pc
5. USB cable ——————————————- 1 pc
6. 1.5 V AAA batteries——————————— 4 pcs

SYMBOLS

Electrical symbols

FUNCTION DIAL AND FUNCTION BUTTONS

Function Dial

Function Buttons

• Short press: Press a button for less than 2 seconds.
• Long press: Press a button for more than 2 seconds.

1. Button
   • Short press to switch between functions in each multi-function position.
2. Button
   • Short press to enter the manual range mode and change the range. Long press to enter auto mode.
3. Button
   • Short press to switch between frequency and duty ratio measurement.
   • Long press to turn on/off data communication (note: only available when USB communication module is inserted into the meter casing).
4. Button
   • Short press to enter/exit the relative value measurement mode.
5. Button
   • Short press to cycle through the measured maximum and minimum.
   • Long press to cycle through the peak maximum and peak minimum.
6. Button
   • Short press to hold the measurement on the display. The symbol “ H ” will be displayed.
   • Short press again to cancel data hold.
   • Long press to turn on/off the backlight.

OPERATING INSTRUCTIONS

• To avoid false reading, replace the battery if the battery low power symbol appears (when the battery voltage is ≤4.6 V ± 0.2 V). Also pay special attention to the warning sign next to the test lead jack, indicating that the tested voltage or current must not exceed the values listed on the meter.
• The meter automatically shuts down if there is no operation for 15 minutes. You can wake up the meter by pressing this button. To disable auto shutdown, press and hold the button in the off state, and then turn on the meter. Restart the meter to restore auto function.
• Buzzer alarm during measurement: When the input voltage >1000 V or current >10 A, the buzzer will sound an alarm.

AC voltage measurement (P 3)

1. Insert the red test lead into the jack, and the black test lead into the COM jack.
2. Turn the function dial to the position.
3. Short-press the button to switch to AC voltage measurement.
4. Connect the test leads in parallel with the measured load or power supply.
5. Read the voltage value on the display (if the voltage is >1000 V, the red indicator light will be lit and the buzzer will sound an alarm).
6. Short-press the button to display the frequency/duty ratio of the measured voltage.

Caution

• Do not input a voltage over 1000 V or it may damage the meter.
• Take care to avoid electric shock when measuring high voltages.
• After completing the measurement, disconnect the test leads from the circuit under test.
• Before each use, verify meter operation by measuring a known voltage.
• The input impedance of the meter is about 10 MΩ. The effect of this load may cause measurement errors in high-impedance circuits. In most cases, if the impedance of the circuit is below 10 kΩ, the error can be ignored (≤0.1%).

DC voltage measurement (P 4)

1. Insert the red test lead into the jack, and the black test lead into the COM jack.
2. Turn the function dial to the position.
3. Short-press the button to switch to DC voltage measurement if required.
4. Connect the test leads to the measured load or power supply in parallel.
5. Read the voltage value on the display (if the voltage is >1000 V, the red indicator light will be on and the buzzer will sound an alarm).

AC/DC millivolt voltage measurement (P 5)

1. Insert the red test lead into the jack, and the black test lead into the COM jack.
2. Turn the function dial to the position.
3. Short press the button to switch to AC/DC millivolt voltage measurement if required.
4. Connect the test leads in parallel with the measured load or power supply.
5. Read the voltage value on the display.
6. When measuring AC millivolt voltage, short-press the button to display the frequency/duty ratio of the measured voltage.

Caution

• Do not input a voltage over 1000 V or it may damage the meter.
• Take care to avoid electric shock when measuring high voltages.
• After completing the measurement, disconnect the test leads from the circuit under test.
• Before each use, verify meter operation by measuring a known voltage.
• The input impedance of the AC mV range is about 10 MΩ. The effect of this load may cause measurement errors in high-impedance circuits. In most cases, if the impedance of the circuit is below 10 kΩ, the error can be ignored (≤0.1%).
• The input impedance of the DC mV range is infinite (about 1 GΩ), and it does not attenuate when measuring weak signals, so the measurement accuracy is high. When the test leads are open, there may be a value on the screen, but this is normal and will not affect the measuring result.
• Frequency measurement at 60 mV range (AC voltage) is for reference only.

LoZ (low impedance) ACV measurement (P 6)

1. Insert the red test lead into the jack, and the black test lead into the COM jack.
2. Turn the function dial to the LozV position.
3. Connect the test leads in parallel with the measured load or power supply.
4. Read the voltage value on the display.
5. Short-press the button to display the frequency/duty ratio of the measured voltage.

Caution

• Do not input a voltage over 1000 V or it may damage the meter.
• Take care to avoid electric shock when measuring high voltages.
• After completing the measurement, disconnect the test leads from the circuit under test.
• Before each use, verify meter operation by measuring a known voltage.
• After using the LoZ function, wait 3 minutes before next operation.
• LoZ ACV measurement eliminates ghost voltage for more accurate measurement.

Resistance measurement (P 7)

1. Insert the red test lead into the jack, and the black test lead into the COM jack.
2. Turn the function dial to the position.
3. Touch the probes to the test points in the circuit.
4. Read the resistance value on the display.

Caution

• Take care when working with voltages above AC 30 V RMS, 42 V peak or DC 60 V. Such voltages pose a shock hazard.
• If the measured resistor is open or the resistance exceeds the maximum range, the LCD will display “OL”.
• Before measuring resistance, switch off the power supply to the circuit, and fully discharge all capacitors.
• When measuring low resistance, the test leads will produce 0.1~0.3 Ω measurement error. To obtain an accurate measurement, short-circuit the test leads and use the relative value measurement (REL) mode.
• If the resistance is not less than 0.5 Ω when the test leads are short-circuited, please check if the test leads are loose or defective.
• When measuring high resistance, it is normal to take a few seconds to stabilize the reading.

Continuity test (P 8)

1. Insert the red test lead into the jack, and the black test lead into the COM jack.
2. Turn the function dial to the position.
3. Short-press the button to switch to continuity test.
4. Touch the probes to the test points in the circuit.
5. Measured resistance <50 Ω: The circuit has good continuity; the buzzer beeps continuously and the green indicator light is on.

Caution

• Take care when working with voltages above AC 30 V RMS, 42 V peak or DC 60 V. Such voltages pose a shock hazard.
• Before testing continuity, switch off the power supply to the circuit, and fully discharge all capacitors.

Diode test (P 9)

1. Insert the red test lead into the jack, and the black test lead into the COM jack.
2. Turn the function dial to the position.
3. Short-press the button to switch to diode test if required.
4. Connect the red probe to the diode anode, and the black probe to the diode cathode.
5. Read the forward bias value on the display.
6. Measured value <0.12 V: The diode may be damaged; the red indicator light is on. Measured value within 0.12~2 V: The diode is normal; the green indicator light is on (for reference only).
7. If the diode is open or its polarity is reversed, the LCD will display “OL”. For silicon PN junction, the normal value is generally about 500~800 mV.

Caution

• Take care when working with voltages above AC 30 V RMS, 42 V peak or DC 60 V. Such voltages pose a shock hazard.
• Before testing the diode, switch off the power supply to the circuit, and fully discharge all capacitors.

Capacitance measurement (P 10)

1. Insert the red test lead into the jack and the black test lead into the COM jack.
2. Turn the function dial to the position.
3. Short-press the button to switch to capacitance measurement.
4. Touch the probes to the capacitor pins.
5. Read the capacitance value on the display after it stabilizes.

Caution

• Take care when working with voltages above AC 30 V RMS, 42 V peak or DC 60 V. Such voltages pose a shock hazard.
• Before measuring, fully discharge all capacitors (especially high-voltage capacitors) to avoid damage to the meter and user.
• If the measured capacitor is short-circuited or the capacitance exceeds the maximum range, the LCD will display “OL”.
• When measuring high capacitance, it is normal to take a few seconds to stabilize the reading.
• For small capacitance measurements, it is recommended that REL mode is used to avoid the influence of distributed capacitance and to obtain a correct reading.

Frequency/Duty ratio measurement (P 11)

1. Insert the red test lead into the terminal, and the black test lead into the COM terminal.
2. Turn the function dial to the Hz% position.
3. Short-press the button to switch to frequency/duty ratio measurement if required.
4. Read the frequency/duty ratio value on the display.

_ Caution: _Take care when working with voltages above AC 30 V RMS, 42 V peak or DC 60 V. Such voltages pose a shock hazard.

Temperature measurement (P 12)

1. Turn the function dial to the °C°F position, “OL” appears on the display.
2. Insert the K-type thermocouple into the adapter socket, then insert the adapter socket into the input terminals.
3. Put the temperature sensing end of the thermocouple close to the object surface under test.
4. Read the temperature value on the display after it stabilizes.
5. Short-press the button to switch between °C and °F.

Caution

• Only a K-type thermocouple can be used.
• Max. temperature 230°C/446°F (°F = °C × 1.8 + 32)

AC/DC current measurement (P 13)

1. Insert the red test lead into the mA/μA or A terminal, and the black test lead into the COM terminal.
2. Turn the function dial to the position.
3. Short-press the button to switch to AC/DC current measurement if required.
4. Connect the test leads in series with the measured load or power supply.
5. Read the current value on the display (if the current is >10 A, the red indicator light will be on and the buzzer will sound an alarm).
6. When measuring AC current, short-press the button to display the frequency/duty ratio of the measured current.

Caution

• To prevent possible electric shock, fire, or personal injury, switch off the power supply to the circuit, then connect the meter in series with the circuit before measuring the current.
• If the range of the measured current is unknown, select the maximum range and then reduce accordingly.
• There are fuses inside mA/μA and A input terminals. Do not connect the test leads in parallel with any circuit.
• If the measured current is >5 A, each measurement time should be ≤10 s and the rest interval should be ≥15 minutes.
• If the temperature of the meter rises above 75°C after measurement of a large current, the yellowindicator light will come on, the buzzer will beep, and the LCD will display “CUT”. When the temperature drops to <40°C, the yellow indicator light will turn off, and the measurement can be made.

Non-contact voltage (NCV) detection (P 14)

1. Turn the function dial to the NCV position.
2. Put the NCV detector (top left corner of the meter) close to the wire (AC) under test.
3. If the voltage of the wire is ≥50 V RMS (frequency: 50/60 Hz), the red indicator light will be on and the buzzer will beep. If no voltage is detected, the LCD will display “EF”. As the intensity of the detected voltage increases, more segments “-” will be displayed, and the frequency of buzzer beeping and red indicator light flashing will increase.

Caution

• The detected voltage level varies with the distance between the NCV detector and the wire under test.
• The detected voltage level is for reference only, not for specific measurement. The frequency of the detected voltage should be 50/60 Hz.
• Hold the meter casing for non-contact voltage detection.

USB data transmission (P 15a, P 15b)

1. Pull out the USB sealing cover at the back of the meter (Picture 15a).
2. Insert the USB communication module into the USB access port of the meter and the LCD will display “ S ” (Picture 15b).
3. If USB data transmission is not needed during measurement, long-press the USB button or pull out the USB module to disable data transmission, and “ S ” will disappear.
4. To recover this function, long-press the USB button or insert the USB module.
5. The USB communication software can be downloaded from the official website of Limit (www.limit-tools.com).

ELECTRICAL SPECIFICATIONS

• Accuracy: ± (a% of reading + b digits).
• Ambient temperature: 23°C ± 5°C (73.4°F ± 9°F)
• Relative humidity: ≤75%

Caution

• To ensure measurement accuracy, the operating temperature should be within 18°C~28°C and the fluctuation range should be within ±1°C.
• When the temperature is <18°C or >28°C, add temperature coefficient error: 0.1 × (specified accuracy)/°C.

DC voltage

• Input impedance: About 1 GΩ for mV range, about l0 MΩ for other ranges
• Accuracy guarantee: 1%~100% of range; short circuit allows least significant digit ≤5
• Max input voltage: 1000 V (if the voltage is >1000V, the red indicator light will be on and the buzzer will sound an alarm; if the voltage is >1010 V, the LCD will display “OL”)
• Overload protection: 1000 V

AC voltage

• Input impedance: About l0 MΩ
• Display: True RMS
• Frequency response: 40 Hz ~ 1 kHz
• The AC crest factor can be ≤3.0 at 3000 counts, and can only be ≤1.5 at 6000 counts. The additional error should be added according to the crest factor for a non-sinusoidal wave, as follows:
  • Add 4% when crest factor is 1~2
  • Add 5% when crest factor is 2~2.5
  • Add 7% when crest factor is 2.5~3
• Frequency measurement range: 40 Hz~1 kHz, input amplitude: ≥10% of voltage range. Duty ratio is for reference only
• Accuracy guarantee: 2%~100% of 60 mV range, 1 %~100% of other ranges; short circuit allows least significant digit ≤3
• Max input voltage: 1000 V (if the voltage is >1000 V the red indicator light will be on and the buzzer will sound an alarm; if the voltage is >1010 V, the LCD will display “OL”)
• Overload protection: 1000 V

Resistance

± (1.0%+2)

60.00 kΩ| 10 Ω
600.0 kΩ| 100 Ω
6.000 MΩ| 1 kΩ| ± (1.2%+2)
60.00 MΩ| 10 kΩ| ± (2.0%+5)

• Measurement result = displayed value – resistance of shorted test leads
• Open-circuit voltage: About 1 V
• Accuracy guarantee: 1%~100% of range
• Overload protection: 1000 V

Continuity and diode

Resistance <50 Ω, audio/visual alarm.

| ****

0.001 V

| Open-circuit voltage: About 3V.

For normal diodes, the buzzer will beep once.

For short circuit, the buzzer will beep for a long time.

• Overload protection: 1000 V
• When the forward voltage drop is within 0.12~2 V, the buzzer will beep once.
• When the forward voltage drop is <0.12 V, the buzzer will beep for a long time.

Capacitance

± (3%+5)

600.0 nF| 100 pF
6.000 μF| 1 nF
60.00 μF| 10 nF
600.0 μF| 100 nF
6.000 mF| 1 μF| ± (10%+5)
60.00 mF| 10 μF

• Overload protection: 1000 V
• Measurement result = Displayed value – capacitance of open-circuit test leads
• For capacitance ≤1 μF, it is recommended to use the REL mode to deduct the open-circuit reading
• Accuracy guarantee: 1~100% of range
• For ranges of 60 mF. the measurement time is about 20 s

Temperature

-40~1000°C

| -40~0°C| ****

0.1°C~1°C

| ± (1.0%+30°C)
0~300°C| ± (1.0%+20°C)
300~1000°C| ± (1.0%+3°C)

-40~1832°F

| -40~32°F| ****

0.2°F~2°F

| ± (1.0%+60°F)
32~572°F| ± (1.0%+40°F)
572~1832°F| ± (1.0%+6°F)

• The measured temperature should be less than 230°C/446°F

DC current

• Overload protection: mA/μA range: F1 Fuse 600 mA 1000 V Ф6 × 32 mm.
• A range: F2 Fuse 11 A 1000 V Ф10 × 38 mm
• Open circuit allows least significant digit ≤5
• Accuracy guarantee: 1~100% of range

AC current

• Display: True RMS
• Frequency response: 40 Hz ~ 1 kHz
• Accuracy guarantee: 5~100% of 600.0 μA range.
• 1~100% of other ranges; open circuit allows least significant digit ≤5
• The AC crest factor can be ≤3.0 at 3000 counts, and can only be ≤1.5 at 6000 counts. The additional error should be added according to the crest factor of a non-sinusoidal wave, as follows:
  • Add 4% when crest factor is 1~2
  • Add 5% when crest factor is 2~2.5
  • Add 7% when crest factor is 2.5~3
• Frequency measurement range: 40 Hz ~ 1 kHz, input amplitude: ≥50% of current range.
• Duty ratio is for reference only
• Frequency accuracy: ± (0.1% + 4); resolution: 0.1 Hz
• Overload protection: Same as for DC current

Frequency/duty ratio

• Frequency input amplitude:
  • ≤100 kHz: 200 mV RMS ≤input amplitude ≤20 V RMS

  • 100 kHz ~ 1 MHz: 600 mV RMS ≤input amplitude ≤20 V RMS

  • 1 MHz: 1 V RMS ≤input amplitude ≤20 V RMS

• Duty ratio measurement is only applicable to square waves.
  • 1 Vpp ≤ input amplitude ≤20 Vpp
  • Frequency ≤10kHz, duty ratio: 10.0~90.0%
• Overload protection: 1000 V

Indicator light

NCV

| Off| <36 V
On, red| 50~1000 V (the red indicator light flashes from slow to fast)

Continuity

| Off| OL
On, red| No continuity (≥70 Ω)
On, green| Continuity (<50 Ω)

Diode

| Off| >2 V
On, red| Breakdown (<0.12 V)
On, green| Conduction (0.12~2V)
AC/DC voltage| Off| ≤1000 V
On, red| >1000 V
Current| Off| ≤10 A
On, red| >10 A
Internal temperature during AC/DC current measurement| Off| The temperature in the meter drops to <40°C after

measurement of large current

On, yellow| The temperature in the meter is ≥75°C after measurement of large current

MAINTENANCE

Warning: Before opening the rear cover or battery cover of the meter, switch off the power supply and remove the test leads.

General maintenance

1. Clean the meter casing with a damp cloth and mild detergent. Do not use abrasives or solvents!
2. If there is any malfunction, stop using the meter and send it for maintenance.
3. Maintenance and servicing must be carried out by qualified professionals or designated departments.
4. Resistance measurement can be used to check the built-in 600 mA and 11 A fuses.

Operation (Picture 16a)

Insert the red test lead into the terminal. Insert the red probe into the mA/μA input terminal to measure the resistance. If the LCD displays “OL”, the 600 mA fuse is blown. Insert the red probe into the A input terminal to measure the resistance. If the LCD displays “OL”, the 11 A fuse is blown.

Battery/Fuse replacement (P 16b)

• Battery: 4 × 1.5 V AAA batteries
• Fuse: F1 Fuse 600 mA 1000 V Ф6 × 32 mm (mA/μA input terminal)
• F2 Fuse 11 A 1000 V Ф10 × 38 mm (A input terminal)
• When “ ” is displayed, please replace the batteries to ensure measurement accuracy.

Replacement steps:

• Turn the function dial to the “OFF” position and remove the test leads.
• Unscrew and remove the battery cover to replace the batteries and fuses.

Contact

• +46 322-60 60 00
• info@limit.se
• limit-tools.com

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