UNI-T UT123 UT123D Smart Multimeter User Manual

1. Overview and Features

The UNI-T UT123 and UT123D are pocket-size residential multimeters designed for ease of use and reliability. Their compact structure allows for comfortable single-hand operation, and the EBTN screen ensures clear readings from various angles. These multimeters adhere to EN61010-1:2010, EN61010-2-030:2010, and EN61326-1:2013 safety standards, featuring full anti-burn protection for safe operation within a CAT III 600V environment.

Key Features:

• Automatic identification of ACV/DCV measurement.
• Intelligent non-contact electric field detection (NCV) with color-coded LED indicators (green for weak, yellow for strong, red for super strong electric fields).
• Automatic battery status detection upon booting: green light for normal, yellow for low battery, red for very low battery with acousto-optic indication.
• Full featured protection.

2. Safety Instructions

Please read these safety instructions carefully before using the multimeter to ensure safe and correct operation.

• Do not use the meter if the rear cover is not installed, as this poses a shock hazard.
• Before each use, inspect the insulation layer of the meter and test leads for any damage or broken wires. Discontinue use if damage is found.
• Always place your fingers behind the finger guard ring of the test leads during use.
• Do not apply voltage exceeding 600V between any meter terminal and earth ground to prevent electric shock and damage.
• Exercise caution when measuring voltages higher than 60V (DC) or 30Vrms (AC) to avoid electric shock.
• Ensure the measured signal does not exceed specified limits to prevent damage to the meter.
• Never change the range setting during measurement to avoid damaging the meter.
• Do not modify the internal circuit of the meter.
• Replace batteries promptly when the low battery symbol 'D' appears on the LCD to maintain measurement accuracy.
• Avoid using or storing the meter in high temperature and high humidity environments, as this may affect its performance.
• Clean the meter casing with a damp cloth and mild detergent. Do not use abrasives or solvents.

3. Operating Instructions

3.1 General Operation

The multimeter performs a battery self-check within 2 seconds of booting:

• Green light: Supply voltage >2.7V, power is sufficient, normal measurement mode.
• Yellow light: Supply voltage 2.4V~2.7V, low battery symbol 'D' appears.
• Red light: Supply voltage <2.4V, meter powers off. Replace batteries.

The meter features an auto-shutdown function. If there is no operation of the range switch or any button for 15 minutes, the meter will automatically shut down to save power. To disable auto-shutdown, turn the range switch to the OFF position, then press and hold the SELECT button (≥2 seconds) while powering up the meter.

3.2 DC/AC Voltage Measurement

1. Turn the range switch to the AC voltage position.
2. Insert the red test lead into the 'VΩ°C' jack and the black test lead into the 'COM' jack.
3. Make the probes contact both ends of the measured voltage (parallel connection to the load).
4. Read the test results on the display.

The meter automatically identifies ACV/DCV (voltage ≥0.5V). For voltages less than 0.5V, press the SELECT button to toggle and lock the measurement mode. After pressing SELECT, auto-identification is disabled until the range switch is turned or the meter is restarted.

Image: Multimeter display showing AC voltage measurement.

3.3 Resistance Measurement

1. Turn the range switch to the resistance measurement position.
2. Insert the red test lead into the 'VΩ°C' jack and the black test lead into the 'COM' jack.
3. Make the probes contact both ends of the measured resistance.
4. Read the test results on the display.

Before measuring online resistance, ensure the circuit's power supply is off and all capacitors are fully discharged. If the resistance is not less than 0.5Ω when test leads are shorted, check for loose or abnormal test leads. If the measured resistor is open or exceeds the maximum range, 'OL' will appear on the display. Do not input voltage higher than DC 60V or AC 30V.

Image: Multimeter measuring resistance on a circuit board.

3.4 Continuity Measurement

1. Turn the range switch to the continuity measurement position.
2. Insert the red test lead into the 'VΩ°C' jack and the black test lead into the 'COM' jack.
3. Make the probes contact the two test points.

• Resistance ≤30Ω: Green indicator light, continuous beeps, small on-resistance.
• Resistance 31Ω~420Ω: Red indicator light, no beep, large on-resistance.
• Resistance >420Ω: No indicator or beep, circuit open, 'OL' displayed.

Before measuring continuity online, ensure the circuit's power supply is off and all capacitors are fully discharged.

Image: Multimeter performing a continuity test.

3.5 Temperature Measurement (°C/°F)

1. Turn the range switch to the temperature measurement position.
2. Insert the plug of the K-type thermocouple into the meter.
3. Fix the temperature sensing probe on the object to be tested and read the temperature value once it is steady.

Note: 'OL' appears when the meter is turned on. Only K-type thermocouples/temperature sensors are applicable (measured temperature should be less than 300 °C/572 °F). The conversion formula is °F = °C * 1.8 + 32.

Image: Multimeter measuring temperature with a thermocouple.

3.6 Non-contact AC Electric Field Sensing (NCV)

1. Turn the range switch to the NCV position.
2. Bring the front end of the meter close to the measured object to start sensing.

The intensity of the electric field is indicated by the LED indicator and segments ('-', '--', '---', '----') on the LCD. More segments and faster beeps indicate higher electric field intensity. The live wire will show a stronger signal than the neutral wire.

Image: Multimeter demonstrating NCV function near a power outlet.

4. Specifications

General Specifications

• Max Display: 4099
• Overload Display: OL
• Sampling Frequency: 3 times/second
• Polarity Display: '-' symbol for negative input, no display for positive polarity.
• Low Battery Indication: The bottom left corner of the LCD displays 'D', and the indicator on top lights up yellow during booting.

Operating Conditions

• Operating Temperature: 0°C~40°C (32°F~104°F)
• Storage Temperature: -10°C~50°C (14°F~122°F)
• Relative Humidity: 0°C~ below 30°C: ≤75%; 30°C~40°C: ≤50%
• Altitude: 0~2000m
• Battery: AAA battery 1.5V×2

Safety Standards

• Design Standards: EN61010-1: 2010; EN61010-2-030:2010; EN 61326-1:2013
• EMC: RF field (1V/m): Overall accuracy = specified accuracy ± 5% of range; RF field (>1V/m): No specified calculation
• Measurement Standards: CAT III 600V, double insulation and material pollution degree II
• Dimensions: 130mm×65mm×28mm
• Weight: About 130g (including batteries)

5. Maintenance

Warning: Before opening the rear cover of the meter, switch off the power supply (remove the test leads from the input terminals and the circuit).

5.1 General Maintenance

• Clean the meter casing with a damp cloth and mild detergent. Do not use abrasives or solvents!
• If there is any malfunction, stop using the meter and send it for maintenance.
• Maintenance and service must be implemented by qualified professionals or designated departments.

5.2 Battery Replacement

Replace the batteries immediately when the low battery symbol 'D' appears on the LCD, otherwise the measurement accuracy might be affected. Use a screwdriver to unscrew the screw on the battery cover, remove the cover, and replace the batteries. Pay attention to the positive and negative polarity when installing new batteries.

6. Troubleshooting

• 'OL' Display: If 'OL' is displayed during voltage or resistance measurement, it indicates that the value is over range or the circuit is open.
• Inaccurate Resistance Reading: If the resistance is not less than 0.5Ω when test leads are shorted, check for loose or abnormal test leads.
• Low Battery Indication: If the low battery symbol 'D' appears, replace the AAA 1.5V batteries promptly to ensure accurate measurements.
• No Sound on Continuity Test: Some users report that the UT123 model may only show visual indication without sound during continuity tests. Verify your model's specific features.

7. User Tips

• The compact size and robust, thick plastic casing make this multimeter durable and convenient for everyday use.
• The rotary switch is noted for its high quality and smooth operation, comparable to higher-end multimeters.
• Continuity testing provides both visual (LED) and auditory feedback, with quick response times.
• The EBTN display offers excellent viewing angles and clear, large digits for easy readability.

8. Warranty and Support

Uni-Trend guarantees that this product is free from any defect in material and workmanship for one year from the purchase date. This warranty does not cover damages caused by accident, negligence, misuse, modification, contamination, or improper handling. For warranty service, please contact your seller directly.

Uni-Trend will not be responsible for any special, indirect, incidental, or subsequent damage or loss caused by using this device. Please note that some countries or regions do not allow limitations on implied warranties and incidental or subsequent damages, so this limitation of liability may not apply to you.

For further support, you can refer to the official user manual PDF: User manual (PDF).

Contact Information:
UNI-TREND TECHNOLOGY (CHINA) CO., LTD.
No. 6, Gong Ye Bei 1st Road, Songshan Lake National High-Tech Industrial Development Zone, Dongguan City, Guangdong Province, China
Tel: (86-769) 8572 3888
Website: www.uni-trend.com