Velleman 3 1/2 Digital Multimeter DVM990BL User Manual

Important Safety Information

Read all safety warnings and operating instructions before using this multimeter. Failure to follow these instructions may result in electric shock, fire, or serious injury. Keep this manual for future reference.

• Always ensure the multimeter is in good working condition and test leads are not damaged before use.
• Do not apply voltage or current that exceeds the maximum specified limits for each range.
• Exercise extreme caution when working with voltages above 30V AC RMS, 42V peak, or 60V DC. These voltages pose a shock hazard.
• Always disconnect the test leads from the circuit before changing functions or ranges.
• Do not operate the multimeter if the battery cover is not properly closed.
• Replace the battery immediately when the low battery indicator appears to ensure accurate readings.

Product Overview

The Velleman DVM990BL is a 3 1/2 digit digital multimeter designed for measuring DC/AC voltage, DC current, resistance, capacitance, frequency, and temperature. It features a large LCD with backlight, low-battery indication, overload protection, diode test, and audible continuity test.

Image: The Velleman DVM990BL Digital Multimeter, shown with its orange casing, large LCD display, rotary function switch, and input jacks. Accompanying the multimeter are red and black test leads, a temperature probe, and the product packaging.

Key Components

• LCD Display: Shows measurement readings, units, and function indicators.
• Function/Range Switch: Rotary switch to select desired measurement function and range.
• Input Jacks: Sockets for connecting test leads and probes (COM, VΩmA, 10A).
• Data Hold Button: Freezes the current reading on the display.
• Backlight Button: Activates the display backlight for improved visibility in low light conditions.

Setup

Battery Installation

The multimeter requires a 9V battery (not always included). Ensure the battery is installed correctly before first use.

1. Turn off the multimeter by setting the function switch to 'OFF'.
2. Locate the battery compartment cover on the back of the unit.
3. Unscrew the retaining screw(s) and remove the cover.
4. Connect the 9V battery to the battery clip, observing correct polarity.
5. Place the battery into the compartment and replace the cover, securing it with the screw(s).

Connecting Test Leads

Proper connection of test leads is crucial for accurate and safe measurements.

1. Insert the black test lead into the 'COM' (common) input jack.
2. For most voltage, resistance, capacitance, frequency, diode, and continuity measurements, insert the red test lead into the 'VΩmA' input jack.
3. For high current measurements (up to 10A), insert the red test lead into the '10A' input jack. Ensure the function switch is set to the appropriate current range.

Operating Instructions

Always ensure the multimeter is set to the correct function and range before making any measurement. Start with a higher range if the expected value is unknown to prevent overload.

DC Voltage Measurement (DCV)

1. Connect the red lead to 'VΩmA' and the black lead to 'COM'.
2. Set the function switch to the desired 'V=' (DC Voltage) range.
3. Connect the test leads across the component or circuit to be measured, observing polarity.
4. Read the voltage value on the display.

AC Voltage Measurement (ACV)

1. Connect the red lead to 'VΩmA' and the black lead to 'COM'.
2. Set the function switch to the desired 'V~' (AC Voltage) range.
3. Connect the test leads across the component or circuit to be measured.
4. Read the voltage value on the display.

DC Current Measurement (DCA)

Caution: Never connect the multimeter in parallel with a voltage source when measuring current, as this can damage the meter and the circuit.

1. For currents up to 200mA, connect the red lead to 'VΩmA'. For currents up to 10A, connect the red lead to '10A'. Connect the black lead to 'COM'.
2. Set the function switch to the desired 'A=' (DC Current) range.
3. Open the circuit where current is to be measured and connect the multimeter in series with the circuit.
4. Read the current value on the display.

Resistance Measurement (OHM)

1. Connect the red lead to 'VΩmA' and the black lead to 'COM'.
2. Set the function switch to the desired 'Ω' (Resistance) range.
3. Ensure the circuit or component is de-energized before measuring resistance.
4. Connect the test leads across the component.
5. Read the resistance value on the display.

Diode Test

1. Connect the red lead to 'VΩmA' and the black lead to 'COM'.
2. Set the function switch to the 'Diode' symbol.
3. Connect the red lead to the anode and the black lead to the cathode of the diode. A forward voltage drop will be displayed.
4. Reverse the leads. The display should show 'OL' (Open Loop) for a good diode.

Continuity Test

1. Connect the red lead to 'VΩmA' and the black lead to 'COM'.
2. Set the function switch to the 'Continuity' symbol (often shared with Diode test).
3. Connect the test leads across the circuit or component.
4. If continuity exists (resistance below a certain threshold), the buzzer will sound, and the display will show the resistance value.

Capacitance Measurement (CAP)

1. Connect the red lead to 'VΩmA' and the black lead to 'COM'.
2. Set the function switch to the 'F' (Capacitance) range.
3. Ensure the capacitor is fully discharged before measurement to prevent damage to the meter.
4. Connect the test leads across the capacitor.
5. Read the capacitance value on the display.

Frequency Measurement (Hz)

1. Connect the red lead to 'VΩmA' and the black lead to 'COM'.
2. Set the function switch to the 'Hz' (Frequency) range.
3. Connect the test leads across the signal source.
4. Read the frequency value on the display.

Temperature Measurement (TEMP)

1. Connect the temperature probe (if included) to the appropriate input jacks (usually VΩmA and COM, or dedicated temperature jacks if present).
2. Set the function switch to the '°C' or '°F' (Temperature) range.
3. Place the probe tip on or near the object whose temperature is to be measured.
4. Read the temperature value on the display.

Data Hold Function

Press the 'HOLD' button to freeze the current reading on the display. Press it again to release the hold and resume live measurements.

Backlight Function

Press the 'LIGHT' button to turn on the display backlight. This improves visibility in dimly lit environments. Press it again to turn off the backlight.

Maintenance

Battery Replacement

When the low battery indicator appears on the display, replace the battery promptly to ensure accurate readings and proper operation.

1. Turn off the multimeter and disconnect all test leads from any circuit and from the input jacks.
2. Follow the battery installation steps outlined in the 'Setup' section.
3. Dispose of the old battery responsibly according to local regulations.

Cleaning

To clean the multimeter, wipe the case with a damp cloth and a mild detergent. Do not use abrasives or solvents. Ensure the meter is completely dry before use.

Storage

If the multimeter is not to be used for an extended period, remove the battery to prevent leakage and store the device in a cool, dry place away from direct sunlight.

Troubleshooting

Specifications

• Display: 3 1/2 digit LCD with backlight
• DC Voltage (DCV): Max. 1000V
• AC Voltage (ACV): Max. 700V
• DC Current (DCA): Max. 10A
• Resistance: Max. 20MΩ
• Capacitance: Max. 20µF
• Frequency: Max. 20kHz
• Temperature: -20°C to 1000°C
• Diode Test: Yes
• Audible Continuity Test: Yes
• Low-Battery Indication: Yes
• Overload Protection: Yes
• Data Hold Function: Yes
• Holster: Included
• Plug-in Protection: The corresponding input is opened for each selected range.

Warranty and Support

For detailed warranty information, technical support, or service inquiries, please refer to the official Velleman website or contact your authorized Velleman dealer. Keep your purchase receipt as proof of purchase.