GVDA GD128PLUS Smart Digital Multimeter User Manual

1. Introduction

This meter is an intelligent true RMS digital multimeter. It features intelligent and professional measurement functions, with a full-function gear display and an analog bar multiple display. It is designed for measuring AC/DC voltage, AC/DC current, resistance, capacitance, continuity, diode, NCV (Non-Contact Voltage), frequency, and temperature.

1.1. Overview

The GVDA GD128PLUS is a versatile digital multimeter equipped with a VA color display screen and a maximum display count of 9999. It supports both auto and manual ranging, offering a sampling rate of approximately 3 times per second. Key features include over-range display ("OL"), low voltage indication, a supporting bracket for convenience, and a rechargeable 3.7V Li battery. It also provides input jack indication to guide correct probe placement.

• (1) Power On/Off Button
• (2) Charge Jack
• (3) NCV (Non-Contact Voltage) Sensor
• (4) Warning Indicator
• (5) Display Screen
• (6) Flashlight Key
• (7) Input Jack Indicator
• (8) 10A Jack (for high current measurements)
• (9) mA Jack (for milliampere current measurements)
• (10) COM Jack (common ground for all measurements)
• (11) Input Jack (for voltage, resistance, capacitance, frequency, temperature, diode, continuity)
• (12) Flashlight

1.2. Safety Statement

Caution: Operations that may cause damage to the meter or other equipment.

Warning: Operations that may cause danger to users.

1.3. Safety Instructions

The meter conforms to IEC61010-1 international electrical safety standard. The design and manufacture 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:

• Read this manual carefully and pay special attention to safety warnings before using the meter.
• Operate the meter according to the manual; otherwise, the protection function may be damaged or weakened.
• Take special care when measuring values that exceed 60VDC, 30VAC RMS, or 42V, as these voltages pose a risk 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 if the meter works normally. If it is not normal or damaged, do not use it.
• Before use, check for cracks or damaged plastic parts in the instrument shell. If found, do not use it.
• Before use, check if the probes are cracked or damaged. If so, replace them with probes of the same model and electrical specification.
• Use the meter according to the measurement category, voltage, or current rating specified in the meter or manual.
• Observe local and national safety regulations. Wear personal protective equipment (e.g., approved rubber gloves, masks, flame retardant clothing) to prevent injury from electric shock and arc flash when dangerous live conductors are exposed.
• If the low battery symbol ("") is displayed, replace the battery promptly to prevent measurement error.
• Do not use the meter in environments with explosive gas, steam, or high humidity.
• When using probes, hold your fingers behind the probe finger guard.
• When measuring, connect the null or ground wire first, then the live wire. When disconnecting, disconnect the live wire first, then the null or ground wire.
• Remove the probes from the meter before opening the case or battery cover. Do not use the meter if it is disassembled or the battery cover is open.
• The meter must only be used with the provided probes that meet safety standards. If a probe is damaged, it must be replaced with one of the same model and electrical specification.

2. Product Features

• Display: VA Color Large HD LCD Display, 9999 Counts
• Measurement Modes: Auto Range and Manual Range
• Sampling Rate: Approximately 3 times per second
• Over Range Indication: "OL" displayed for values exceeding range
• Low Voltage Indication: Low battery symbol displayed
• Power Supply: 1200mA 3.7V rechargeable Li battery
• Convenience: Integrated supporting bracket, Input Jack Indication, Flashlights
• Special Functions: Max/Min Measurement, Relative Value Measurement, NCV (Non-Contact Voltage), Diode Test, Continuity Test, Live Wire Detection, True RMS, Fuse Burning Prompt, Auto Power Off, Data Hold
• Certifications: CE certified, conforms to IEC61010-1

3. Setup

3.1. Initial Charging

The multimeter is equipped with a 1200mA 3.7V rechargeable Li battery. Before first use, ensure the device is fully charged. Connect the provided charging cable to the charge jack (2) on the multimeter and to a suitable USB power source.

3.2. Probe Connection

For most measurements (voltage, resistance, capacitance, frequency, temperature, diode, continuity), insert the red probe into the INPUT jack (11) and the black probe into the COM jack (10).

For mA current measurements, insert the red probe into the mA jack (9) and the black probe into the COM jack (10).

For 10A current measurements, insert the red probe into the 10A jack (8) and the black probe into the COM jack (10).

The Input Jack Indicator (7) will flash to prompt correct probe insertion when changing gears.

4. Operating Instructions

4.1. Power On/Off

Press and hold the Power On/Off button (1) for approximately 2 seconds to turn the meter on or off.

4.2. Range Selection

Press the "RANGE" button to enter manual range mode. Press it again to cycle through available ranges. Press and hold "RANGE" for about 2 seconds to return to automatic range. This function is invalid in intelligent measurement mode. Only voltage, resistance, and mA gears are valid for manual range selection.

4.3. Gear Selection

Press the "FUNC" button to enter manual shift mode. Press it again to select the desired shift position. Press and hold "FUNC" for about 2 seconds to return to intelligent (auto) measurement mode. The meter defaults to intelligent measurement mode upon power-on. For multiple functions within one gear, press the "SEL" button to switch.

4.4. Max/Min Measurement

Press the "MAX MIN" button to enter maximum/minimum measurement mode. Press it again to cycle through maximum and minimum values. Press and hold "MAX MIN" for about 2 seconds to return to normal measurement. This function is invalid for capacitance, frequency/duty cycle, temperature, NCV/Live measurements. The instrument will automatically enter manual range mode during Max/Min measurement.

4.5. Relative Value Measurement

Press and hold the "HOLD REL" button for about 2 seconds to turn on or off relative value measurement. This function is invalid for continuity, frequency, duty cycle, temperature, NCV/Live measurements. The meter will automatically enter manual range mode.

4.6. Data Hold

Press the "HOLD REL" button to turn on or off data holding. This function is invalid for NCV/Live measurements.

4.7. Flashlight

Press the "SEL" button to turn the flashlight on or off.

4.8. Smart (AUTO) Measurement

This is the default measurement mode upon power-on. In this mode, the meter automatically identifies and measures DC voltage, AC voltage, resistance, and continuity.

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Insert the red probe into the INPUT jack (11) and the black probe into the COM jack (10).
3. Contact the probes with both ends of the measured power supply or resistance (in parallel). The meter will automatically recognize the signal.
4. Read the results from the display.

4.9. Professional Measurement Modes

For specific measurements, you can manually select the function using the "FUNC" button.

4.9.1. AC/DC Voltage Measurement

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the voltage ("V") gear. The display will show "DC" for DC voltage measurement. Press "SEL" to switch to "AC" for AC voltage measurement.
3. Insert the red probe into the INPUT jack (11) and the black probe into the COM jack (10).
4. Contact the probes with both ends of the measured power supply (in parallel).
5. Read the results from the display.

4.9.2. Resistance Measurement

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the resistance ("Ω") gear.
3. Insert the red probe into the INPUT jack (11) and the black probe into the COM jack (10).
4. Contact the probes with both ends of the measured resistance (in parallel).
5. Read the results from the display.

4.9.3. Continuity Test

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the continuity ("") gear.
3. Insert the red probe into the INPUT jack (11) and the black probe into the COM jack (10).
4. Contact the probes with both ends of the measured resistance or circuit (in parallel).
5. If the resistance value is less than 50 Ω, the buzzer will sound and the alarm indicator will light up.
6. Read the results from the display.

4.9.4. Diode Test

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the diode ("") gear.
3. Insert the red probe into the INPUT jack (11) and the black probe into the COM jack (10).
4. The red probe contacts the anode of the diode and the black probe contacts the cathode.
5. If the probe polarity is opposite to the diode polarity, the display will show "OL".
6. Read the results from the display.

4.9.5. Capacitance Measurement

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the capacitance ("") gear.
3. Insert the red probe into the INPUT jack (11) and the black probe into the COM jack (10).
4. Contact the probes with both ends of the measured capacitance (in parallel).
5. Read the results from the display.

4.9.6. AC/DC mV Voltage Measurement

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the mV voltage ("mV") gear. The display will show "DC" for DC mV voltage measurement. Press "SEL" to switch to "AC" for AC mV voltage measurement.
3. Insert the red probe into the INPUT jack (11) and the black probe into the COM jack (10).
4. Contact the probes with both ends of the measured power supply.
5. Read the results from the display.

4.9.7. Frequency/Duty Measurement

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the frequency/duty ("Hz%") gear.
3. Insert the red probe into the INPUT jack (11) and the black probe into the COM jack (10).
4. Contact the probes with both ends of the measured power supply.
5. Read the results from the display.

4.9.8. Temperature Measurement

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the temperature ("°C/°F") gear.
3. Insert the positive pole of the K-type thermocouple into the INPUT jack (11) and the negative pole into the COM jack (10).
4. The thermocouple probe contacts the measured object.
5. Read the results from the display.

4.9.9. Non-Contact AC Voltage Detection (NCV)

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the "NCV/Live" gear. The display will show the "NCV" symbol.
3. Gradually move the NCV sensor area (3) close to the conductor.
4. When a weak electric field signal is detected, it will display "---L", and the buzzer will sound slowly with a green light.
5. When a strong electric field signal is detected, it will display "---H", and the buzzer will sound quickly with a red light.

4.9.10. Live Wire Detecting

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the "NCV/Live" gear. Press "SEL" to display the "LIVE" symbol.
3. Insert the red probe into the INPUT jack (11) 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", and the buzzer will sound slowly with a green light.
6. When a strong electric field signal is detected, it will display "---H", and the buzzer will sound quickly with a red light.

4.9.11. mA Current Measurement

Caution: Do not measure current greater than 630 mA in this gear, otherwise the mA fuse will be burnt out.

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the "mA" gear. Alternatively, insert the red probe into the mA jack (9) to automatically select the "mA" gear.
3. The display will show "DC" for DC current measurement. Press "SEL" to switch to "AC" for AC current measurement.
4. Insert the red probe into the mA jack (9) and the black probe into the COM jack (10).
5. Connect the meter in series to the measured power supply.
6. Read the results from the display.

4.9.12. Ampere (A) Current Measurement

Caution: Do not measure current greater than 10A in this gear, otherwise the 10A fuse will be burnt out.

1. Press the Power On/Off button (1) to start the machine. The display will show "Auto".
2. Press "FUNC" to select the "A" gear. Alternatively, insert the red probe into the 10A jack (8) to automatically select the "A" gear.
3. The display will show "DC" for DC current measurement. Press "SEL" to switch to "AC" for AC current measurement.
4. Insert the red probe into the 10A jack (8) and the black probe into the COM jack (10).
5. Connect the meter in series to the measured power supply.
6. Read the results from the display.

4.10. Input Jack Indicator

When the measurement gear is changed, the corresponding input light will flash 5 times to prompt the user to insert the probe into the correct jack.

4.11. Auto Power Off

After power on, the auto power off function is enabled by default, indicated by the "C" symbol. If no key operation occurs for approximately 15 minutes, the meter will automatically shut down to conserve battery energy. To disable this function, press the "SEL" key. The "C" symbol will disappear when the function is off.

5. Technical Specifications

5.1. General Specifications

• Environment Condition of Use: CAT. IV 600V; CAT. III 1000V; Pollution level 2, Altitude < 2000m
• Operating Temperature & Humidity: 0~40°C (<80% RH, <10°C non-condensing)
• Storage Temperature & 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: F630mA/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: "-" displayed for negative polarity
• Power Requirement: 3.7V Li battery rechargeable (1200mA)
• Dimensions: 166mm * 83mm * 29mm
• Product Weight: 273g

5.2. 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).

5.2.1. DC Voltage

5.2.2. AC Voltage

5.2.3. AC/DC Current

Overload protection: mA: F630mA/250V fuse, 10A: F10A/250V fuse. Note: The time to measure ampere current must be less than 15 seconds.

5.2.4. Diode/Continuity

5.2.5. Resistance

Overload protection: 250V

5.2.6. Capacitance

Overload protection: 250V

5.2.7. Frequency/Duty

5.2.8. Temperature

Resolution: 1°C/1°F. Note: Use K-type thermocouple probe.

6. Maintenance

6.1. Cleaning

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.

6.2. Battery Replacement

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. 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, 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, remove the battery when it is not used for a long time to prevent battery leakage from damaging the product.

6.3. Fuse Replacement

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, use a fuse of the same specification or specified specification.

7. Troubleshooting

• "OL" Display: Indicates an over-range condition. The measured value exceeds the meter's maximum capacity for the selected range. Switch to a higher range if available, or note that the value is beyond measurement limits.
• Low Battery Indication: If the battery symbol is displayed, the battery charge is low. Replace or recharge the battery promptly to ensure accurate readings and proper operation.
• "FUSE" Display: If "FUSE" is displayed, it indicates that a fuse is burnt out. This typically occurs during current measurements if the current exceeds the fuse rating. Replace the fuse with one of the correct specification immediately.
• "LEAD" Display: If "LEAD" is displayed when attempting a measurement, it means that the test leads are not inserted into the correct jacks for the selected function. Refer to the Input Jack Indicator section (4.10) for correct placement.
• No Continuity Beep: If the continuity test does not produce a beep, ensure the circuit resistance is below approximately 50 Ω. Check connections and the circuit for breaks.

8. User Tips

• Versatility: This multimeter is highly versatile, capable of accurately measuring a wide range of electrical parameters including AC/DC voltage and current, resistance, capacitance, frequency, and temperature.
• Ease of Use: The VA color display screen provides clear, easy-to-read measurements. The auto-ranging feature simplifies operation, making it suitable for both beginners and experienced users.
• Safety Features: Utilize the live wire detection and NCV features for enhanced safety when working with electrical circuits. The input jack indication helps prevent incorrect probe connections.
• Portability: Its compact size and integrated bracket make it convenient for fieldwork and hands-free operation.
• Rechargeable Battery: The built-in rechargeable Li battery offers convenience and reduces the need for disposable batteries. Remember to charge it regularly.

9. Package Contents

The following items are included in your product package:

• 1x GVDA GD128PLUS Smart Digital Multimeter
• 1x Test Lead Set (Pen cable)
• 1x Cloth Bag
• 1x K-type Thermocouple Probe
• 1x Charging Cable
• 1x User Manual (this document, also available as PDF)

10. Warranty and Support

This GVDA GD128PLUS Smart Digital Multimeter is designed and manufactured to meet high-quality standards and is CE certified, conforming to IEC61010-1 international electrical safety standards.

For detailed warranty information, troubleshooting guides, and further technical support, please refer to the complete user manual PDF available at: GVDA GD128PLUS User Manual (PDF).