MASTFUYI Digital Clamp Meter Multimeter User Manual

1. Overview

The MASTFUYI Digital Clamp Meter series (Models FY215, FY217, FY219) are professional clamp multimeters designed for high-precision electrical measurements. These meters feature auto-ranging, True RMS capabilities, and a 6000-count display, making them suitable for various electrical tasks.

Equipped with a full-range intelligent burnout protection circuit and a unique design, these instruments offer superior performance and safety. They can be used to measure AC and DC voltage, AC/DC current, resistance, capacitance, frequency, temperature, diode, and continuity. The FY219 model, as the highest configuration, includes additional features such as surge current, temperature measurement, and low impedance voltage functions.

2. Safety Instructions

▲ Warning: Read all safety information and related precautions carefully before using the meter to avoid potential electric shock, personal injury, or damage to the instrument.

• These instruments are designed and produced according to the safety standards of EN61010-1 and EN61010-2-000 for electronic measuring instruments, with overvoltage category CAT III 600V and pollution level 2.
• The user must use the meter strictly in accordance with the provisions of this manual. Failure to do so may weaken or invalidate the protection provided by the meter.
• Before opening the case or battery covers, ensure the test leads are removed from the meter.
• For maintenance, use a soft cloth and neutral detergent to clean the instrument's case. Do not use abrasives or chemical solvents.
• Before each use, inspect the meter's casing for damage. Do not use the meter if the casing is damaged, especially around the input jacks.
• Check if the insulation of the test probes is damaged or if any metal is exposed. Verify the continuity of the test leads.
• If the meter operates abnormally, do not use it. The protective device may have been damaged. If in doubt, send the meter for repair.
• Do not apply a voltage exceeding the maximum rated value for any function.
• Exercise caution when measuring voltages exceeding 30V AC effective value, as there is a risk of electric shock.
• When connecting test leads, always connect the common (black) test lead first, then the live (red) test lead. When disconnecting, remove the live test lead first.
• When measuring AC current, place the wire to be measured in the center of the clamp head.
• When the voltage between the circuit and the ground exceeds 600V, do not perform measurements.

Electrical Symbols

• ▲: Important safety information / Warning
• ~: AC (Alternating Current)
• =: DC (Direct Current)
• ~=: AC or DC
• ⏚: Ground wire
• CAT III: Overvoltage Category III

3. Product Description

Instrument Components

1. Clamp Head AC/DC Current Transformer: Used for non-contact current measurement.
2. Protector: Designed to protect the clamp head.
3. Clamp Head Trigger: Opens and closes the clamp head.
4. SEL / V.F.C Function Switch Key: Selects functions or Variable Frequency Control.
5. Data Hold and Backlight Button: Locks the current reading and controls the display backlight.
6. Reset Mode & Surge Current Switch Key: Resets certain modes and activates surge current measurement.
7. LCD Screen: Displays measurement readings and indicators.
8. Black Test Lead Input (COM): Common terminal for test leads.
9. Red Test Lead Input (INPUT): Input terminal for test leads.
10. Function Selection Knob: Rotary switch to select measurement modes.
11. LED Flashlight: Illuminates the work area.
12. NCV Voltage Detection: Non-contact voltage detection area.

4. Setup

Battery Installation

The meter requires 2 x 1.5V AAA batteries for operation. Ensure batteries are installed correctly before use.

1. Remove the battery cover on the back of the meter by loosening the screw.
2. Insert two 1.5V AAA batteries, observing the correct polarity (+/-).
3. Replace the battery cover and tighten the screw.

▲ Warning: Replace the battery immediately when the low battery indicator "⎕" appears on the LCD to ensure accurate readings and prevent electric shock or personal injury.

5. Operating Instructions

Key Operations

• "SEL" Button: Function selection key. Press to cycle through different measurement modes within a single rotary switch position (e.g., AC/DC current, resistance/continuity/diode).
• "H/" Button: Data Hold / Backlight. Press once to lock the current reading (an "H" symbol will appear on the LCD). Press again to release. Long press to turn the backlight on/off.
• Flashlight Button: Press to turn the LED flashlight on/off.
• "NCV/LIVE" Button: Activates Non-Contact Voltage (NCV) detection or Live wire checking mode.

Measurement Operations

▲ Warning: Always ensure the correct function and range are selected before making any measurement. Disconnect power to the circuit before measuring resistance, continuity, or capacitance.

AC/DC Voltage Measurement

1. Turn the function knob to the AC Voltage (V~) or DC Voltage (V=) position.
2. Insert the black test lead into the COM jack and the red test lead into the INPUT jack.
3. Touch the test probes to the circuit points to be measured.
4. Read the measured value from the LCD screen. For DC voltage, the display will show polarity.

AC/DC Current Measurement (Clamp Head)

1. Turn the function knob to the AC Current (A~) or DC Current (A=) position.
2. Press the trigger to open the clamp head.
3. Clamp the wire carrying the current to be measured within the center of the clamp head. Ensure only one conductor is clamped for accurate readings.
4. Slowly release the trigger until the clamp head is completely closed.
5. Read the measured value from the LCD screen.

Resistance, Continuity, and Diode Measurement

1. Turn the function knob to the Resistance (Ω), Diode (▶|), or Continuity ())) position. Use the "SEL" button to cycle if needed.
2. Insert the black test lead into the COM jack and the red test lead into the INPUT jack.
3. For resistance, touch the probes across the component. For continuity, touch the probes across the circuit; a buzzer will sound for low resistance. For diode, touch the probes across the diode; the forward voltage drop will be displayed.

Capacitance Measurement

1. Turn the function knob to the Capacitance (∔) position.
2. Insert the black test lead into the COM jack and the red test lead into the INPUT jack.
3. Touch the test probes across the capacitor.
4. Read the measured value from the LCD screen.

Non-Contact Voltage (NCV) Detection

1. Turn the function knob to the NCV position or press the NCV button.
2. Place the sensing area at the top of the instrument clamp close to the power supply or wire.
3. The meter will detect an AC power signal and give an alarm (audible and visual).

Temperature Measurement (FY219 only)

1. Turn the function knob to the Temperature (°C/°F) position.
2. Connect the thermocouple probe to the INPUT and COM jacks, observing polarity.
3. Place the tip of the thermocouple probe on or in the object whose temperature is to be measured.
4. Read the temperature from the LCD screen.

Inrush Current Measurement (FY219 only)

Press the INR ZERO key in the AC current range to select inrush surge current measurement. Start the appliance, and the meter will measure the instantaneous starting current.

Variable Frequency Voltage (V.F.C) Measurement (FY217, FY219 only)

This function allows for accurate measurement of non-sinusoidal AC voltages, which is common in modern electronics with variable frequency drives.

Low Impedance Voltage (LOWz) Measurement (FY219 only)

This mode helps in safely dealing with false voltages in circuits, providing more reliable troubleshooting by accurately judging the true situation of circuit voltage.

6. Specifications

The following table outlines the general specifications and measurement ranges for the MASTFUYI Digital Clamp Meter series. Note that specific features and ranges may vary by model (FY215, FY217, FY219).

General Specifications

• Max Display Range: 6000 Counts
• Display Type: Digital Only
• True RMS: Yes
• Input Polarity Display: Yes
• Low Power Prompt: Yes
• Flashlight: Yes
• Backlight: Yes
• Automatic Shutdown: Yes (Approx. 15 minutes)
• Power Supply Type: 2 * 1.5V AAA Batteries
• Operating Environment: 0-40°C (<80% RH, not considered when <10°C)
• Storage Environment: -10-60°C (<70% RH)
• Altitude: <2000 m
• Pollution Degree: 2
• Sampling Rate: Approx. 3 times/second
• Over-range Indication: LCD displays "OL" or "-OL"
• Certifications: CE, FCC, RoHS

Detailed Measurement Ranges and Accuracy

7. Maintenance

General Maintenance

• To avoid injury or damage to the meter, do not allow moisture inside the meter.
• Before opening the case or battery cover, ensure all test leads are disconnected from the input signal.
• Clean the meter's case with a soft cloth and neutral detergent. Do not use abrasives or chemical solvents.
• If the input jacks are dirty or wet, clean them thoroughly. Remove all dirt from the jacks. Dip a new cotton swab with detergent or lubricant (such as WD-40) and clean the jacks.

Battery Replacement

▲ Warning: To avoid false readings and potential electric shock or personal injury, replace the batteries immediately when the low battery symbol appears on the display.

1. Ensure the meter is turned off and all test leads are disconnected.
2. Loosen the screw fixing the battery cover on the back of the meter.
3. Remove the old batteries.
4. Replace with 2 new 1.5V AAA batteries, ensuring correct polarity.
5. Reinstall the battery cover and tighten the screw.

8. Troubleshooting

If the meter is not functioning as expected, please check the following common issues:

• Meter does not turn on: Check if the batteries are installed correctly and have sufficient charge. Replace batteries if necessary.
• Inaccurate readings: Ensure the correct function and range are selected. Check test lead connections for proper contact and damage. Verify that the battery is not low.
• No continuity buzzer: Ensure the meter is in continuity mode. Check if the circuit resistance is within the audible range.
• NCV not detecting: Ensure the meter is in NCV mode. The sensing area should be close to the AC voltage source.
• Display shows "OL": This indicates an over-range condition. The measured value exceeds the selected range. Switch to a higher range if available, or if it's a fixed range, the value is simply too high for the meter.

9. User Tips

• Always start with the highest range: When measuring an unknown voltage or current, it's a good practice to start with the highest range setting and then decrease it until you get a stable and accurate reading. This prevents overloading the meter.
• Check test leads regularly: Periodically inspect your test leads for any signs of wear, cuts, or damage to the insulation. Damaged leads can pose a safety hazard and lead to inaccurate measurements.
• Use data hold for convenience: When taking measurements in hard-to-reach or poorly lit areas, use the data hold function to freeze the reading on the display, allowing you to view it more comfortably.
• Understand True RMS: For non-sinusoidal waveforms (common in modern electronics), True RMS meters provide more accurate readings than average-responding meters. If your model has True RMS, leverage this feature for precise measurements.
• Safety first: Always prioritize safety. Never work on live circuits without proper training and safety equipment. Double-check your connections and settings before making any measurement.

10. Support

For further assistance, technical support, or inquiries regarding your MASTFUYI Digital Clamp Meter, please refer to the official product page or contact the seller directly.

A PDF version of the user manual is available for download: User Manual (PDF)