UNI-T UT109, UNI-T, Digital Multimeter

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3¾ digit automotive multimeter to measure voltages, currents, resistances, frequencies, temperatures and many automotive values, like dwell, battery, engine speed and testing of many different sensors.

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Description

The UNI-T digital automotive multimeter provides a sophisticated measurement technology at a very good price / performance ratio. The automotive Multimeter UT109 effectively helps diagnosing problems with the electronic components of an automobile. This part gives a special introduction as to how the Meter UT109 is used to diagnose any trouble with a fuse, switch, solenoid, relay, starting and charging systems, ignition system, fuel system and engine sensor.

Besides the quality, the measurement devices distinguish by their ease of use, good legibility of the display and sophisticated measurement functions. UNI-T digital multimeters also fulfill the important details of everyday measuring, such as the almost immediate response of the continuity test, reliable measurement results, and conservative use of the battery. If you have ever worked with a digital multimeter from one of the various cheap manufacturers, you are familiar with problems such as continuity tests taking several seconds, noticeable deviation of measurement results if the battery is low, and rapid battery drain...

Dwell Testing

It was very important in the past to test the dwell of the cut-off switch of an ignition system. "Dwell testing" is measuring the duration of a cut-off switch remaining off, while the cam is turning. As an automobile is now ignited electronically, it is no longer necessary to adjust the dwell. In addition, the dwell testing can also be used to test a mixed-controlled solenoid. (e.g. GM feedback carburetor).

Starting/Charging System Testing

The on-off package of the engine starting system consists of a battery, engine starting button, solenoid and relay starting buttons, lead connections and lines. During the operation of the engine, the charging system keeps the battery charged. This system consists of an AC generator, voltage calibrator, lead connections and circuits. The multimeter is an effective tool for checking these systems.

Fuse Testing
Load-Free Battery Testing
Battery Power Consumption Testing when the Engine Is off
Switch Testing
Solenoid or Relay Testing
Trigger Voltage Battery Load Testing
Voltage Drop Testing
Charging System Voltage Testing
Trigger Voltage Battery Load Testing

Engine Tach Testing (Rotation Speed, RPMx10)

The RPM means the rotating frequency of the main shaft of the engine per minute.

Hall Switch/Sensor Testing / Magnetic Resistance Sensor

When the tach and dwell are tested in the computer of the automobile, a Hall sensor is used. The Hall sensor is normally used in the ignition system to detect the position of the camshaft, so the computer of the automobile can set the optimal time for the ignition and the opening of the fuel injector. The functions of a magnetic resistance sensor is similar to those of a Hall sensor, and the testing methods of both sensors are also similar.

Fuel System Testing

It is necessary to add a more accurate engine fuel control to a low injection automobile. Since 1980, the automotive manufacturing industry uses electronically-controlled carburetor and fuel injection, in order to achieve lower fuel injection

Oxygen Sensor

The oxygen sensor is used to test the oxygen content in the exhaust, giving rise to an appropriate voltage or resistance. A low voltage (high resistance) means the excessive output of oxygen content in the exhaust, while a high voltage (low resistance) results in insufficient oxygen content. The computer regulates the ratio between the air and the fuel according to the high or low voltage.

PC Measurement Possibilities

The UNI-T UT109 has a built-in RS232 interface for PC communications. Together with its software, it is possible to receive, record and perform long time data measurements with graphical visualization.

It can save up to 2-3 Sa/s, depending on the measurement function selected (DCV, Resistance, Frequency, ...)

Specifications

Measurement	Range	Accuracy	Resolution
DC Voltage (DCV)	40.00 mV 400.0 mV 4.000 V 40.00 V 400.0 V 1000 V	±(0.8%+3 dig.) ±(0.8%+3 dig.) ±(0.5%+3 dig.) ±(0.5%+3 dig.) ±(0.5%+3 dig.) ±(0.5%+3 dig.)	0.01 mV 0.1 mV 1 mV 10 mV 100 mV 1 V
AC Voltage (ACV) 40 Hz - 1 kHz	4.000 V 40.00 V 400.0 V 1000 V	±(1.0%+3 dig.) ±(1.0%+3 dig.) ±(1.0%+3 dig.) ±(1.2%+5 dig.)	1 mV 10 mV 100 mV 1 V
DC Current (DCA)	400.0 µA 4000 µA 40.00 mA 400.0 mA 4.000 A 10.00 A	±(1.0%+2 dig.) ±(1.0%+2 dig.) ±(1.2%+3 dig.) ±(1.2%+3 dig.) ±(1.5%+3 dig.) ±(1.5%+3 dig.)	0.1 µA 1 µA 10 µA 100 µA 1 mA 10 mA
AC Current (ACA)	400.0 µA 4000 µA 40.00 mA 400.0 mA 4.000 A 10.00 A	±(1.2%+5 dig.) ±(1.2%+5 dig.) ±(1.5%+5 dig.) ±(1.5%+5 dig.) ±(2.0%+5 dig.) ±(2.0%+5 dig.)	0.1 µA 1 µA 10 µA 100 µA 1 mA 10 mA
Resistance	400.0 Ω 4.000 kΩ 40.00 kΩ 400.0 kΩ 4.000 MΩ 40.00 MΩ	±(1.0%+5 dig.) ±(1.0%+5 dig.) ±(1.0%+5 dig.) ±(1.0%+5 dig.) ±(1.0%+5 dig.) ±(1.5%+5 dig.)	0.1 Ω 1 Ω 10 Ω 100 Ω 1 kΩ 10 kΩ
Capacitance	10.00 nF 100.0 nF 1000 nF 10.00 µF 100.0 µF	±(3.0%+5 dig.) ±(3.0%+5 dig.) ±(3.0%+5 dig.) ±(3.0%+5 dig.) ±(3.0%+5 dig.)	10 pF 100 pF 1 nF 10 nF 100nF
12 V Battery (120 Ω / 2 W load)	20.00 V	±(3.0%+5 dig.)	10 mV
Frequency	10 Hz ~ 1 MHz	±(0.1%+4 dig.)	1 Hz
Dwell Testing	4 CYL 6 CYL 8 CYL	±(3.0%+5 dig.) ±(3.0%+5 dig.) ±(3.0%+5 dig.)	0.1° 0.1° 0.1°
Tach (Rotation Speed) Testing	4 CYL 6 CYL 8 CYL	±(3.0%+5 dig.) ±(3.0%+5 dig.) ±(3.0%+5 dig.)	10 RPM 10 RPM 10 RPM
Temperature °C ¹⁾	-40°C ~ 537°C	±(1.0%+10 dig.)	1°C
Temperature °F ¹⁾	-40°F ~ 998°F	±(1.0%+18 dig.)	2°F

¹⁾The included K-type temperature probe can be used for temperatures up to 230°C, do not use it with higher temperatures!

Function	Digital Multimeter UT109
RS232 Interface
True RMS (TRMS)
Auto Range
Manual Range
Data Logging
Data Recall
Diode test
Transistor test
Continuity test	(fast reaction time below 0.5 seconds)
Low battery indication
Relatively measuring
Data hold
Min-Max / Peak hold
Auto power-off
Overload protection	X Fuse 1: F1 A 240 V, ⌀6.4 x 25.4 mm; Fuse 2: F10 A 240 V, ⌀6.4 x 25.4 mm
Shockproof Protection
Backlight
"Analogue" Bargraph	(41 steps)
Max. Reading	3999 (3¾digits)
LCD Size	65 mm x 43 mm
Sampling rate	Approx. 2-3 times / second

Details	Digital Multimeter UT109
Battery	9 V Block Battery (included in delivery)
Safety standard	CAT II 1000 V CAT III 600 V
Dimensions	17.9 cm × 8.8 cm × 3.9 cm (7.05" × 3.46" × 1.54")
Weight without accessories / packaging	363 g (with battery) (0.80 lb)
Weight with accessories / packaging	700 g (1.54 lbs)
Warranty	2 Years