AstroAI TRUE RMS 4000 Count Intelligent Digital Multimeter

Introduction

Thank you for purchasing the TRUE RMS 4000 Count Intelligent Digital Multimeter from AstroAI.

The AstroAI TRUE RMS 4000 Count Intelligent Digital Multimeter is designed for safe and accurate use by professionals in commercial environments or by weekend DIYers who require more from their standard digital multimeter. This manual contains all safety instructions, operating instructions, specifications, and maintenance information for the device. The device measures AC/DC current, AC/DC voltage, resistance, diode, capacitance, Hz/Duty, and temperature.

Thank you again for choosing AstroAI. If you have any questions or suggestions regarding this product, please contact us at support@astroai.com.

Please read this manual thoroughly before use and keep it for future reference.

EC REP: APEX CE SPECIALISTS LIMITED, UNIT 3D NORTH POINT HOUSE, NORTH POINT BUSINESS PARK, NEW MALLOW ROAD, CORK, T23 AT2P, IRELAND

Safety Precautions (HINWEISE)

• Before using the multimeter, inspect the outer casing. Do not use the multimeter if it is damaged or if the outer casing is partially or fully removed. Check for cracks or missing plastic. Pay special attention to the insulation around the terminals.
• Check the test leads for damaged insulation or exposed metal. Test the test leads for continuity.
• Do not apply more than the rated voltage indicated on the multimeter between the terminals or between a terminal and ground.
• The rotary selector switch must be set to the correct position before measurement and must NOT be moved during measurement to avoid damaging the multimeter.
• When the multimeter is operating with a voltage exceeding 60V DC or 30V AC, exercise extreme caution due to the risk of electric shock.
• Use the correct terminals, functions, and ranges for your measurements.
• Do not use or store the multimeter in an environment with high temperatures, high humidity, or near strong magnetic fields. Performance may degrade after exposure to moisture.
• When using the test leads, keep your fingers behind the finger guards.
• Disconnect the circuit from the power source and discharge all high-voltage capacitors before testing resistance, continuity, diodes, or hFE.
• Disconnect the connection between the test leads and the circuit under test, and turn off the multimeter before opening the device casing.
• Replace the battery as soon as the battery indicator appears. A weak battery can cause the device to display incorrect readings, potentially leading to electric shock and injury.
• When servicing the multimeter, use only replacement parts with the same model number or identical electrical specifications.
• The internal circuitry of the device must not be modified arbitrarily to avoid damage to the device and accidents.
• Clean the surface of the device with a soft cloth and a mild detergent. Do not use abrasive cleaners or solvents to protect the surface from corrosion and damage.
• Turn off the multimeter when not in use, and remove the battery if it will not be used for an extended period. Check the battery regularly, as it may leak if left unused for a long time. Replace the battery if it has leaked. A leaking battery can damage the multimeter.

Dimensions

The multimeter has physical dimensions of approximately 76mm (width) x 158mm (height) x 35mm (depth).

Diagram and Symbols

Symbols:

Functions

• Select Button: When a multimeter function is selected with the rotary dial, use the 'Select' button to further choose the specific function (e.g., for multi-functional settings like Capacitors, Resistors, Diodes, Continuity, and AC/DC Current selection).
• Hold/Backlight Button: During a measurement, press this button to hold the data for easier recording. Press again to deactivate the hold function. Press and hold the button to turn on the LCD backlight; press again to turn it off.
• Hz/Duty Button: When using the 'Hz%' function, press this button to quickly switch between functions. You can also switch to the Hz/Duty Cycle measurement function when measuring AC voltages.
• Relative Button: To obtain more accurate measurements, you can use the 'Relative' button. To activate this function, simply press the 'Relative' button. A small triangle (Delta symbol △) will appear on the display, and the measured value will reset to zero. Press the 'Relative' button again to exit Relative mode.
• Range Button: For AC/DC voltage, AC/DC current, and resistance, measurements can be made in both auto and manual ranges. The multimeter is set to Auto by default upon delivery. If you wish to select the range manually, press the Range button repeatedly to find the desired range. Ensure you do not select too low a range, as this may overload the device and prevent it from displaying a reading. Hold the 'Range' button to return to automatic range selection.
• Max/Min Button: Press this button once during a measurement to activate 'Max-Mode', where the multimeter records the highest measured value. Press the button again to switch to 'Min-Mode', which records the lowest measured value. Hold this button to exit Max/Min mode.
• Temperature Measurement Input: The temperature measurement function uses the K-type thermocouple. Connect the thermocouple's negative (black) plug to the COM jack and the positive (red) plug to the INPUT jack.

I. Voltage Measurement (Spannungsmessung)

Lead Connection: Connect the black test lead to the 'COM' jack and the red test lead to the 'INPUT' jack.

Function Selection: Set the rotary dial to 'V~' for AC voltage or 'V=' for DC voltage, corresponding to the measured voltage characteristic.

Circuit Connection: Connect the other end of the test leads to the circuit to be measured and connect them in parallel with the circuit.

Reading: Read the value displayed on the LCD.

Notes:

• When measuring a small range, if the test lead is not connected to the load, the multimeter may show unstable results. This is normal and does not affect the measurement.
• When measuring DC voltage, polarity is determined by the presence or absence of a '-' sign. The absence of '-' indicates a positive connection.
• To avoid damaging the multimeter, do not measure voltages exceeding 600V DC or 600V AC.
• When measuring AC voltage, you can use the 'Hz/Duty' button to switch between test frequency and duty cycle.
• If the measured voltage is unknown, press the 'Range' button to select the maximum range first, then select the appropriate range based on the initial value for satisfactory resolution. If the multimeter displays 'OL' or the circuit is outside the measurement range, select a higher range. For automatic operation, the 'Range' button does not need to be pressed.
• Do not use the AC voltage function to test DC voltages, and vice versa. This can lead to incorrect readings and damage the multimeter or the device under test.
• Finding a Live Wire in an Outlet:
  1. Switch to the voltage test setting.
  2. Connect the black test lead to the grounded wire or socket, and the red test lead to one of the sockets to be measured.
  3. Test both sockets. One should display a reading, and the other should remain at or near zero. The live wire will show the reading.

Ending Measurement: When measurement is complete, turn off the device by setting the rotary dial to 'OFF'.

II. Current Measurement (Strommessung)

Lead Connection: Connect the black test lead to the 'COM' jack and the red test lead to the 'INPUT' jack for currents less than 500mA. For currents between 500mA and 10A, connect the red test lead to the 'A' jack instead.

Function Selection: Set the rotary dial according to the estimated current value: 'µA≈', 'mA≈', or 'A≈'.

Test Condition Selection: Use the 'Select' button to choose between DC or AC current measurement based on the circuit characteristic.

Circuit Connection: Connect the test lead in series with the circuit or load to be measured.

Reading: Read the value displayed on the LCD.

Notes:

• To avoid damaging the multimeter, do not measure more than 10A AC or DC.
• For DC current measurements, polarity is determined by the display showing '-' or not.
• For testing strong currents, each measurement should last less than 10 seconds for safety reasons, with intervals of more than 15 minutes between tests.
• A load must be present in the circuit when testing current. Do not connect the multimeter in series with the circuit without a load, as this can damage the multimeter.
• If the measured current is unknown, use the 'Range' button to select the maximum range first, then adjust to the appropriate range for satisfactory resolution. If 'OL' is displayed, select a higher range. For automatic operation, the 'Range' button is not needed.
• Parasitic Battery Drain in Vehicles:
  1. Turn off all electrical devices inside and outside the vehicle and close the doors.
  2. Check if battery voltage and current generation are within normal range (typically 12.7V for battery, 14V for generation).
  3. Disconnect the negative battery electrode. Set the multimeter to the maximum current setting and connect it in series with the battery.
  4. Connect the red test lead to the negative terminal and the black test lead to the battery terminal.
  5. If necessary, set the multimeter to a lower range.
  6. Wait approximately 30 minutes for all vehicle modules to enter sleep mode, then read the static discharge current. This is typically 0.02A (20mA) but varies by vehicle. Generally, 50mA should not be exceeded.
  7. If the discharge current exceeds 50mA, check fuses individually to identify the circuit drawing excessive load.
  8. If removing a fuse reduces battery drain to below 50mA, that circuit is identified as the source of the excessive discharge.

Ending Measurement: When measurement is complete, turn off the device by setting the rotary dial to 'OFF'.

III. Resistance Measurement (Widerstandsmessung)

Lead Connection: Connect the black test lead to the 'COM' jack and the red test lead to the 'INPUT' jack.

Continuity Test:

1. Set the rotary dial to 'Ω'. Use the 'Select' button to choose the continuity mode; the symbol '•))' will appear on the display.
2. Touch the red and black test leads together. If you hear a continuous beep ?, the test is functioning correctly.

Function Selection: Use the 'Select' button to choose the resistance test function.

Circuit Connection: Connect the test leads to the circuit or component to be measured, in parallel with the circuit.

Reading: Read the value displayed on the LCD.

Notes:

• For resistance measurements >1MΩ, it may take several seconds for the reading to stabilize. This is normal for high resistance measurements.
• Do not change the resistance while performing a measurement, as this can damage the multimeter and affect the results.
• Do not test parallel circuits directly; accuracy may be compromised.
• Do not directly measure the internal resistance of micrometers, galvanometers, batteries, or other instruments.
• If the input is not connected (open circuit), the 'OL' symbol indicates an out-of-range condition.
• Before measuring the resistance of a circuit, ensure the circuit is de-energized and all capacitors are fully discharged.
• Use the 'Range' button for manual range selection if needed. If the measured value is unknown, select the maximum range first and then adjust for better resolution. 'OL' indicates an out-of-range condition.

Ending Measurement: When measurement is complete, turn off the device by setting the rotary dial to 'OFF'.

IV. Continuity Test (Durchgangsprüfung)

Lead Connection: Connect the black test lead to the 'COM' jack and the red test lead to the 'INPUT' jack.

Continuity Test Procedure:

1. Set the rotary dial to the continuity symbol (speaker icon •)). Use the 'Select' button to confirm the continuity mode; the symbol '•))' will appear on the display.
2. Touch the red and black test leads together. If you hear a continuous beep ?, the test is functioning correctly.

Load Connection: Connect the test leads to both sides of the circuit or load to be measured.

Reading: Read the value displayed on the LCD.

Notes:

• If the resistance is between 50Ω and 100Ω, the summer may or may not sound. If the resistance is over 100Ω, the summer will not sound.

Ending Measurement: When measurement is complete, turn off the device by setting the rotary dial to 'OFF'.

V. Diode Test (Diodentest)

Lead Connection: Connect the black test lead to the 'COM' jack and the red test lead to the 'INPUT' jack.

Function Selection: Press the 'Select' button to choose the diode test function; the symbol '►' will appear on the display.

Diode Connection: Connect the red test lead to the anode of the diode to be tested and the black test lead to the cathode.

Reading: Read the value displayed on the LCD.

Notes:

• Correct Diode Function: When the red lead is connected to the diode's positive terminal and the black lead to the negative terminal, the diode should be in forward bias, and the displayed value represents the forward voltage drop.
• Normal Diode Forward Voltage Drop: The average for silicon diodes is 0.5-0.7V; for germanium diodes, it is 0.15-0.3V.
• Polarity Judgment Method:
  1. Set the multimeter to resistance mode.
  2. Connect the test leads to both electrodes of the diode.
  3. Measure the result, then reverse the test leads and measure again.
  4. The larger result is the reverse resistance, and the smaller result is the forward resistance. The smaller resistance occurs when the black lead is connected to the diode's positive end and the red lead to the negative end.

Ending Measurement: When measurement is complete, turn off the device by setting the rotary dial to 'OFF'.

VI. Capacitance Measurement (Kapazitätsmessung)

Lead Connection: Connect the black test lead to the 'COM' jack and the red test lead to the 'INPUT' jack.

Continuity Test:

1. Set the rotary dial to 'Ω'. Use the 'Select' button to choose the continuity mode; the symbol '•))' will appear on the display.
2. Touch the red and black test leads together. If you hear a continuous beep ?, the test is functioning correctly.

Function Selection: Press the 'Select' button to choose the capacitance test function.

Capacitance Connection: Connect the capacitor to be measured, with the capacitor's positive pole connected to the red wire and the capacitor's negative pole connected to the black wire.

Reading: Read the value displayed on the LCD.

Ending Measurement: When measurement is complete, turn off the device by setting the rotary dial to 'OFF'.

VII. Temperature Measurement (Temperaturmessung)

Connection: Insert the negative (black) plug of the K-type thermocouple into the 'COM' jack and the positive (red) plug into the 'INPUT' jack.

Function Selection: Set the rotary dial to '°C' or '°F'.

Test Method: Carefully touch the object to be measured with the tip of the K-type thermocouple.

Reading: Read the value displayed on the LCD until the temperature reading stabilizes.

Ending Measurement: When measurement is complete, turn off the device by setting the rotary dial to 'OFF'.

VIII. Frequency Measurement (Frequenzmessung)

Lead Connection: Connect the black test lead to the 'COM' jack and the red test lead to the 'INPUT' jack.

Continuity Test:

1. Set the rotary dial to 'Ω'. Use the 'Select' button to choose the continuity mode; the symbol '•))' will appear on the display.
2. Touch the red and black test leads together. If you hear a continuous beep ?, the test is functioning correctly.

Function Selection: Set the dial to 'Hz%' and use the 'Hz/Duty' button to switch between test frequency and duty cycle.

Signal Source Connection: Connect the test leads to the circuit to be measured.

Reading: Read the value displayed on the LCD.

Ending Measurement: When measurement is complete, turn off the device by setting the rotary dial to 'OFF'.

Specifications

General Specifications

Detailed Specifications

Accuracy is guaranteed for 1 year at 23°C±5°C/73°F ±9°F under 80% relative humidity.

I. DC Voltage (Automatic Range)

Input Impedance: 10MΩ

Overload Protection: 600V DC or 600V AC RMS

Max. Input Voltage: 600V DC

II. AC Voltage (Automatic Range)

Input Impedance: 10MΩ

Frequency Response: 40Hz~400Hz

Overload Protection: 600V DC/AC RMS

Response: Average value, calibrated to RMS of sine wave

Max. Input Voltage: 600V AC RMS

III. Temperature

NOTE: Different temperature sensors are configured for different temperature test ranges, and normal temperature sensors are intended for standard configuration.

IV. DC Current

Overload Protection: µA- and mA-ranges: F0.5A/600V fuse

4A- and 10A-ranges: F10A/600V fuse

Max. Input Current: INPUT jack: 200mA

'A' jack: 10A

(For measurements >5A: measure only in time spans of less than 10 seconds, with intervals of more than 15 minutes)

Voltage Drop: 400µA, 40mA and 4A ranges: 40mV

4000μA, 400mA and 10A ranges: 400mV

V. AC Current

Overload Protection: µA- and mA-ranges: F0.5A/600V fuse

4A- and 10A-ranges: F10A/600V fuse

Max. Input Current: INPUT jack: 200mA

'A' jack: 10A

(For measurements >5A: measure only in time spans of less than 10 seconds, with intervals of more than 15 minutes.)

Voltage Drop: 400µA, 40mA and 4A ranges: 40mV

4000μA, 400mA and 10A ranges: 400mV

Frequency Response: 40Hz ~ 400Hz

Response: Average, calibrated in RMS of sine wave

VI. Resistance (Automatic Range)

Open Circuit Voltage: ~0.25V

Overload Protection: 250V DC/AC RMS

VII. Diode and Continuity

For Continuity Test: If resistance is between 50Ω and 100Ω, the buzzer may or may not sound. If resistance is over 100Ω, the buzzer will not sound.

VIII. Capacitance

IX. Frequency

Package Contents (LIEFERUMFANG)

• 1 x User Manual
• 1 x Pair of Test Leads
• 1 x K-Type Thermocouple
• 1 x AstroAI 4000 Count Multimeter

Recycling

When you wish to dispose of this product, please note that it is made of many valuable materials, some of which can be reused. Please recycle the relevant materials according to local sorting regulations.

Warranty

AstroAI offers a 3-year warranty on this product.

Every AstroAI 4000 Count Digital Multimeter is free from material and workmanship defects. This warranty does not cover fuses, disposable batteries, and damage caused by abnormal operating or handling conditions such as negligence, misuse, contamination, modification, accidents, etc., including overvoltage failures caused by using the multimeter outside its specified ratings or by normal wear and tear of mechanical parts. This warranty is valid only for the original purchaser and is non-transferable.

If this product is defective, please contact AstroAI Customer Service at support@astroai.com.