GVDA GD128 Smart Digital Multimeter User Manual

1. Safety Information

1.1 Safety Statement

Before using the instrument, please read this manual carefully and save it well for future use.

▲ Caution:

Operation that may cause damage to the meter or equipment.

▲ Warning:

Operation that may cause danger to users.

1.2 Safety Instructions

• The meter conforms to IEC61010-1 international electrical safety standard. The design and manufacture of the meter comply with IEC61010-1 CAT.III 1000V, CAT.IV 600V overvoltage safety standard and pollution level 2.
• To avoid possible electric shock or personal injury, please observe the following specifications:
• Please read this manual carefully and pay special attention to safety warning information before using the meter.
• Operate the meter according to the manual, otherwise the protection function provided by the instrument may be damaged or weakened.
• Take special care when measuring values that exceed 60VDC, 30VAC RMS, or 42V. This kind of voltage has the danger of electric shock.
• Do not measure voltage higher than the rated value between terminals or between terminals and ground.
• Measure a known voltage to check whether the meter works normally. If it is not normal or damaged, please do not use it again.
• Before using the meter, please check whether there are cracks or damaged plastic parts in the instrument shell. If so, please do not use it again.
• Before using the meter, please check whether the probe is cracked or damaged. If so, please replace the probe with the same model and the same electrical specification.
• Please use the meter according to the measurement category, voltage or current rating specified in the meter or manual.
• Please observe local and national safety regulations. Wear personal protective equipment (such as approved rubber gloves, masks and flame retardant clothing, etc.) to prevent injury caused by electric shock and electric arc when dangerous live conductors are exposed.
• When the battery symbol is displayed on the meter, please replace the battery in time to prevent measurement error.
• Do not use the meter in an environment with explosive gas or steam or humid environment.
• When using the probe, please hold your fingers behind the probe finger guard.
• When measuring, please connect the null or ground wire first, then the live wire; when disconnected, please disconnect the live wire first, and then the null or ground wire.
• Remove the probe from the meter before opening the case or battery cover. Do not use the meter when the meter is disassembled or the battery cover is opened.
• The meter can only be used together with the probe provided to meet the requirements of the safety standard. If the probe is damaged and needs to be replaced, the probe of the same model and electrical specification must be replaced.

2. Product Overview

The GVDA GD128 is an intelligent true RMS digital multimeter designed for accurate and reliable electrical measurements. It features a full function set with gear display and an analog bar for multiple display options.

2.1 Product Features

• Smart Auto Range: Automatically selects the appropriate range for accurate readings.
• True RMS: Provides accurate readings of current, voltage, and resistance, even on non-linear loads.
• Wide Range: Measures up to 1000V and 10A, handling a broad spectrum of electrical measurements.
• Digital Display: Large VA HD LCD color screen for easy-to-read results in various lighting conditions.
• Input Jack LED Indication: Flashing jacks guide correct probe placement.
• LED Spot Lights Lamp: Integrated flashlight for working in dimly lit areas.
• Silicon Protective Case: Durable case for enhanced protection.

2.2 Parts Identification

Diagram of the GVDA GD128 Multimeter showing its various components.

1. NCV Sensor area
2. Power key
3. Warning indicator
4. Flashlight key
5. Input jack indicator
6. Display
7. Function key
8. Auto power off key
9. Flashlight
10. Jack other than current and NCV
11. COM jack
12. mA(<600mA) jack
13. 10A jack

3. Setup

3.1 Battery Installation

The multimeter requires 3x AAA batteries (not included).

Image showing the battery compartment with 3xAAA batteries.

1. Turn off the meter power and remove the probes.
2. Remove the screw fixing the battery cover and remove the battery cover.
3. Remove the old battery and replace it with a new one of the same specification. Please pay attention to the battery polarity.
4. Install the battery cover back to its original position, and fix and lock the battery cover with screws.

▲ Warning:

To avoid electric shock or personal injury caused by wrong reading, please replace the battery immediately when the battery is low. Do not discharge the battery by shorting it or reversing its polarity. To operate and maintain the meter safely, please take out the battery when it is not used for a long time to prevent battery leakage from damaging the product.

3.2 Probe Connection

Always ensure probes are correctly inserted into the appropriate jacks for the desired measurement. The input jack indicator will flash to guide you.

• For most measurements (Voltage, Resistance, Capacitance, Frequency, Diode, Continuity, Temperature): Insert the red probe into the VHz%°C/°F jack and the black probe into the COM jack.
• For mA Current Measurement: Insert the red probe into the mA(<600mA) jack and the black probe into the COM jack.
• For Ampere (A) Current Measurement: Insert the red probe into the 10A jack and the black probe into the COM jack.

4. Operation

4.1 Power On / Off

Press and hold the power key () for about 2 seconds to turn the meter on or off.

4.2 Smart (AUTO) Measurement Mode

This is the default measurement mode when the meter is powered on. In this mode, the meter can automatically identify and measure DC voltage, AC voltage, resistance, and continuity.

The multimeter in Smart Auto Range mode, automatically detecting AC/DC voltage, resistance, and continuity.

1. Press the power key to start the machine; it will display "Auto" and enter the intelligent measurement mode.
2. Insert the red probe into the VHz%°C/°F jack and the black probe into the COM jack.
3. Contact the probes with both ends of the measured power supply or resistance (parallel), and the meter will automatically recognize the measured signal.
4. Read the results from the display.

Note: The minimum measurable voltage in this mode is AC0.5V; DC0.8V.

4.3 Professional Measurement (Manual Mode)

To access specific measurement functions, press the "AUTO/FUNC" key to enter manual shift mode. Press it repeatedly to cycle through functions, or press and hold for about 2 seconds to return to intelligent (auto) measurement mode.

4.3.1 AC/DC Voltage Measurement

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "~" gear. The "DC" symbol will be displayed for DC voltage measurement. Press the "SEL" key to switch to the "AC" symbol for AC voltage measurement.
3. Insert the red probe into the VHz%°C/°F jack and the black probe into the COM jack.
4. Contact the probe with both ends of the measured power supply (parallel).
5. Read the results from the display.

4.3.2 Resistance Measurement

Image showing the multimeter performing a resistance measurement.

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "Ω" gear.
3. Insert the red probe into the VHz%°C/°F jack and the black probe into the COM jack.
4. Contact the probe with both ends of the measured resistance (parallel).
5. Read the results from the display.

4.3.3 Continuity Test

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the ")))" gear.
3. Insert the red probe into the VHz%°C/°F jack and the black probe into the COM jack.
4. Contact the probe with both ends of the measured resistance or circuit (parallel).
5. When the resistance value is less than 50 Ω, the buzzer will sound and the alarm indicator will be on.
6. Read the results from the display.

4.3.4 Diode Test

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "→|" gear.
3. Insert the red probe into the VHz%°C/°F jack and the black probe into the COM jack.
4. The red probe contacts the anode of the diode and the black probe contacts the cathode of the diode.
5. If the probe polarity is opposite to the diode polarity, the display will show "OL".
6. Read the results from the display.

4.3.5 Capacitance Measurement

Image showing the multimeter performing a capacitance measurement.

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "╪" gear.
3. Insert the red probe into the VHz%°C/°F jack and the black probe into the COM jack.
4. Contact the probe with both ends of the measured capacitance (parallel).
5. Read the results from the display.

4.3.6 AC/DC mV Voltage Measurement

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "mV" gear. The "DC" symbol will be displayed for DC voltage measurement. Press the "SEL" key to switch to the "AC" symbol for AC voltage measurement.
3. Insert the red probe into the VHz%°C/°F jack and the black probe into the COM jack.
4. Contact the probe with both ends of the measured power supply.
5. Read the results from the display.

4.3.7 Frequency/Duty Measurement

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "Hz%" gear.
3. Insert the red probe into the VHz%°C/°F jack and the black probe into the COM jack.
4. Contact the probe with both ends of the measured power supply.
5. Read the results from the display.

4.3.8 Temperature Measurement

Image showing the multimeter measuring temperature using the K-type thermocouple probe.

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "°C/°F" gear.
3. Insert the positive pole of the K-type thermocouple into the VHz%°C/°F jack and the negative pole into the COM jack.
4. The thermocouple probe contacts the measured object.
5. Read the results from the display.

4.3.9 Non-contact AC Voltage Detection (NCV)

Image showing the multimeter performing NCV measurement near a power outlet.

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "NCV/Live" gear. The "NCV" symbol will be displayed.
3. The NCV sensor area is gradually brought close to the conductor.
4. When a weak electric field signal is detected, it will display "---L"; the buzzer will sound slowly and the green light will turn on.
5. When a strong electric field signal is detected, it will display "---H"; the buzzer will sound quickly and the red light will turn on.

4.3.10 Live Wire Detecting

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "NCV/Live" gear. Press the "SEL" key to display the "LIVE" symbol.
3. Insert the red probe into the VHz%°C/°F jack and remove the black probe.
4. Use the red probe to contact the conductor.
5. When a weak electric field signal is detected, it will display "---L"; the buzzer will sound slowly and the green light will turn on.
6. When a strong electric field signal is detected, it will display "---H"; the buzzer will sound quickly and the red light will turn on.

4.3.11 mA Current Measurement

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "mA" gear. Or insert the red probe into the mA jack to automatically select the "mA" gear.
3. The "DC" symbol will be displayed for DC current measurement. Press the "SEL" key to switch to the "AC" symbol for AC current measurement.
4. Insert the red probe into the mA jack and the black probe into the COM jack.
5. Connect the meter in series to the measured power supply.
6. Read the results from the display.

▲ Caution:

Do not measure current > 600mA in this gear, otherwise the mA fuse will be burnt out.

4.3.12 Ampere (A) Current Measurement

1. Press the power key to start the machine, display "Auto" and enter the intelligent measurement mode.
2. Press "AUTO/FUNC" key to select the "A" gear. Or insert the red probe into the 10A jack to automatically select the "A" gear.
3. The "DC" symbol will be displayed for DC current measurement. Press the "SEL" key to switch to the "AC" symbol for AC current measurement.
4. Insert the red probe into the 10A jack and the black probe into the COM jack.
5. Connect the meter in series to the measured power supply.
6. Read the results from the display.

▲ Caution:

Do not measure current > 10A in this gear, otherwise the 10A fuse will be burnt out.

4.4 Other Functions

4.4.1 Range Selection

Press the "RANGE" key to enter manual range mode, then press to cycle through ranges. Press and hold "RANGE" key for about 2 seconds to return to automatic range.

Note 1: This function is invalid in intelligent measurement mode.

Note 2: Only voltage, resistance and mA gears are valid.

4.4.2 Max / Min Measurement

Press the "MAX/MIN" key to enter maximum / minimum measurement mode. Press again to cycle through maximum and minimum values. Press and hold for about 2 seconds to return to normal measurement.

Note 1: Invalid in capacitance, frequency/duty cycle, temperature, NCV/Live gear.

Note 2: Maximum / minimum measurement, the instrument will automatically enter the manual range mode.

4.4.3 Relative Value Measurement

Press "REL/HOLD" for about 2 seconds to turn on or off relative value measurement.

Note 1: Invalid in continuity, frequency / duty cycle, temperature, NCV / live.

Note 2: Relative value measurement, the meter will automatically enter the manual range mode.

4.4.4 Data Hold

Press "REL/HOLD" key to turn on or off data holding.

Note: Invalid in NCV / Live.

4.4.5 Flashlight

Animated image showing the LED flashlight of the multimeter.

Press the flashlight key to turn on or off the flashlight.

4.4.6 Auto Power Off (APO)

After power on, auto power off will be on by default and the "APO" symbol will be displayed. Without any key operation for about 15 minutes, the meter will automatically shut down to save battery energy.

Press the "APO" key to turn on or off the automatic shutdown function. When no "APO" symbol is displayed, the automatic shutdown function is turned off.

5. Maintenance

5.1 Cleaning

When cleaning the meter, please follow these steps:

1. Turn off the meter power and remove the probes.
2. Wipe the case with a damp cloth or mild detergent. Do not use abrasives or solvents.
3. Wipe the contacts in each input socket with a clean swab soaked in alcohol.

▲ Warning:

Always keep the inside of the meter clean and dry to prevent electric shock or damage to the meter.

5.2 Replacing the Fuse

If the fuse is burnt out, the symbol "E" will be displayed. When the current gear is selected, the symbol "FUSE" will be displayed. It is not allowed to measure the current. Please replace the fuse in time.

1. Turn off the meter power and remove the probes.
2. Remove the screw fixing the back cover and remove the back cover.
3. Remove the burnt out fuse, replace it with a new one of the same specification, and ensure that the fuse is installed in the safety clip and clamped tightly.
4. Install the back cover and fix it with screws.

▲ Warning:

To prevent electric shock, personal injury or damage to the meter, please use insurance of the same specification or specified specification.

6. Troubleshooting

• Meter does not power on: Check if batteries are installed correctly and have sufficient charge. Replace if necessary.
• Inaccurate readings: Ensure probes are clean and properly connected. Verify the correct measurement mode is selected. Check battery level.
• "OL" displayed: Indicates an over-range condition. Select a higher range if in manual mode, or check if the measured value exceeds the meter's maximum capacity.
• Low battery indicator: Replace batteries immediately to ensure accurate measurements.
• Fuse burning prompt: If "E" or "FUSE" is displayed, the fuse is blown. Replace it as per the maintenance section.
• No continuity beep: Ensure the continuity test mode is selected and the resistance is below 50 Ω.

7. Specifications

7.1 General Technical Specifications

• Environment Condition of Using: CAT. IV 600V; CAT. III 1000V; Pollution level 2, Altitude < 2000m
• Working Temperature and Humidity: 0~40°C (<80% RH, <10°C non condensing)
• Storage Temperature and Humidity: -10~60°C (<70% RH, remove the battery)
• Temperature Coefficient: 0.1× accuracy /°C (<18°C or >28°C)
• MAX. Voltage between terminals and earth ground: DC1000V/AC750V
• Fuse Protection:
  • mA: F600mA/250V fuse
  • 10A: F10A/250V fuse
• Sampling Rate: Approx. 3 times/second
• Display: 9999 counts, VA Color Display Screen
• Over Range Indication: "OL"
• Low Battery Indication: Battery symbol displayed
• Input Polarity Indication: Display "-"
• Power Requirement: 3 x 1.5V AAA alkalinity batteries
• Product Weight: Approx. 230g
• Product Size: 83x23x165mm
• Package Size: 170x95x50mm
• Package Weight: 470g
• Safety Rating: EN61010-1,-2-030 EN61010-2-033, EN61326-1 CAT III 1000V CAT IV 600V

7.2 Accuracy Specifications

The accuracy applies within one year after calibration. Reference condition: environment temperature 18°C to 28°C, relative humidity no more than 80%. Accuracy: ± (% reading + word).

Note: Use K-type thermocouple probe for temperature measurement.

8. User Tips

• Capacitor Measurement: Yes, this model (GD128) is capable of measuring capacitance. Ensure you select the correct capacitance range or use the smart auto-range feature for convenience.
• Smart Mode Efficiency: For general troubleshooting and quick checks, the Smart Auto Range mode is highly efficient as it automatically identifies the measurement type (voltage, resistance, continuity) and selects the best range.
• Safety First: Always prioritize safety. Use the NCV feature to detect live wires before making contact, and ensure probes are correctly inserted and in good condition.
• Clear Display: The large VA HD LCD color screen makes readings clear, even in challenging light conditions. Utilize the built-in flashlight when working in dark areas.

9. Warranty and Support

For warranty information, technical support, or service inquiries, please refer to the documentation provided with your purchase or contact the manufacturer directly. Keep your purchase receipt as proof of purchase.

10. Product Demonstration Video

A video demonstrating the features and operation of the GVDA GD128 Smart Digital Multimeter.