Model UT90A: OPERATING MANUAL Table of Contents Title Page Overview Unpacking Inspection Safety Information Rules For Safe Operation International Electrical Symbols The Meter Structure Rotary Switch Functional Buttons Display Symbols Measurement Operation A. DC Voltage Measurement B. AC Voltage Measurement C. DC Current Measurement D. AC Current Measurement E. Resistance Measurement F. Testing Diodes & Continuity G. Battery Test General Specifications Accuracy Specifications A. DC Voltage B.
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Model UT90A: OPERATING MANUAL Overview This Operating Manual covers information on safety and cautions. Please read the relevant information carefully and observe all the Warnings and Notes strictly. Warning To avoid electric shock or personal injury, read the "Safety Information" and "Rules for Safe Operation" carefully before using the Meter. The Model UT90A (hereafter referred to as “the Meter”) is a 1999 counts 3 1/2 digits multimeter with stabilized functions, safe design, and reliable performance.
Model UT90A: OPERATING MANUAL Unpacking Inspection Open the package case and take out the Meter. Check the following items carefully to see any missing or damaged part: Item 1 2 3 4 Description English Operating Manual Test Lead 9V Battery (NEDA 1604, 6F22 or 006P) Holster Qty 1 piece 1 pair 1 piece 1 piece In the event you find any missing or damage, please contact your dealer immediately.
Model UT90A: OPERATING MANUAL Safety Information This Meter complies with standards IEC61010: in pollution degree 2, overvoltage category (CAT. II 1000V, CAT. III 600V) and double insulation. CAT.II: Local level, appliance, PORTABLE EQUIPMENT etc., with smaller transient overvoltages than CAT. III CAT.III: Distribution level, fixed installation, with smaller transient overvoltages than CAT.
Model UT90A: OPERATING MANUAL Rules For Safe Operation (1) Warning To avoid possible electric shock or personal injury, and to avoid possible damage to the Meter or to the equipment under test, adhere to the following rules: l l l l l l l l l Before using the Meter inspect the case. Do not use the Meter if it is damaged or the case (or part of the case) is removed. Look for cracks or missing plastic. Pay attention to the insulation around the connectors.
Model UT90A: OPERATING MANUAL Rules For Safe Operation (2) l l l l l l l When servicing the Meter, use only the same model number or identical electrical specifications replacement parts. The internal circuit of the Meter shall not be altered at will to avoid damage of the Meter and any accident. Soft cloth and mild detergent should be used to clean the surface of the Meter when servicing. No abrasive and solvent should be used to prevent the surface of the Meter from corrosion, damage and accident.
Model UT90A: OPERATING MANUAL International Electrical Symbols AC (Alternating Current). DC (Direct Current). AC or DC. Grounding. Double Insulated. Deficiency of Built-In Battery. Continuity Test. Diode. Fuse. Warning. Refer to the Operating Manual. Conforms to Standards of European Union.
Model UT90A: OPERATING MANUAL The Meter Structure (see figure 1) ( figure 1) 1 2 3 4 5 LCD Display. Hold Button. Rotary Switch. Input Terminals. Power Button.
Model UT90A: OPERATING MANUAL AC Current Measurement Range from 0.
Model UT90A: OPERATING MANUAL Functional Buttons Below table indicated for information about the functional button operations. AC voltage measurement. Turn the power on and off. HOLD l l l Press HOLD once to enter hold mode. Press HOLD again to exit hold mode and the present value is shown.
Model UT90A: OPERATING MANUAL Display Symbols(1) (see figure 2) mVVΩk ΩMΩ AC µ AmAA ( figure 2) No. Symbol 1 2 3 AC 4 5 6 7 8 Connect Terminal Meaning The battery is low. Warning: To avoid false readings, which could lead to possible electric shock or personal injury, replace the battery as soon as the battery indicator appears. High voltage indicator Indicator for AC voltage or current. The displayed value is the mean value. Indicates negative reading. Test of diode. The continuity buzzer is on.
Model UT90A: OPERATING MANUAL Display Symbols(2) (see figure 2) No. 9 Symbol Meaning Ω: Ohm. The unit of resistance. Ω,kΩ,MΩ kΩ: kilohm.1 x 103 or 1000 ohms. MΩ: Megaohm. 1 x 106 or 1,000,000 ohms. mV, V V: Volts. The unit of voltage. mV: Millivolt. 1 x 10-3 or 0.001 volts. A: Amperes (amps). The unit of current. µA, mA, A mA: Milliamp. 1 x 10-3 or 0.001 amperes. µA: Microamp. 1x 10-6 or 0.000001 amperes.
Model UT90A: OPERATING MANUAL Measurement Operation(1) A.DC Voltage Measurement (see figure 3) red black ( figure 3) Warning To avoid harms to you or damages to the Meter from electric shock, please do not attempt to measure voltages higher than 1000V DC/750V AC although readings may be obtained. The DC voltage ranges are: 200.0mV, 2.000V, 20.00V, 200.0V and 1000V. To measure DC voltage, connect the Meter as follows: 1.
Model UT90A: OPERATING MANUAL Measurement Operation(2) l The LCD displays “1” indicating the existing selected range is overloaded, it is required to select a higher range in order to obtain a correct reading. l In each range, the Meter has an input impedance of approx. 10MΩ. This loading effect can cause measurement errors in high impedance circuits. If the circuit impedance is less than or equal to 10kΩ, the error is negligible (0.1% or less).
Model UT90A: OPERATING MANUAL Measurement Operation(3) B.AC Voltage Measurement (see figure 3) red black ( figure 3) Warning To avoid harms to you or damages to the Meter from electric shock, please do not attempt to measure voltages higher than 1000V DC/750V AC although readings may be obtained. The AC voltage ranges are: 2.000V, 20.00V, 200.0V and 750.0V. To measure AC Voltage, connect the Meter as follows: 1.
Model UT90A: OPERATING MANUAL Measurement Operation(4) l The LCD displays “1” indicating the existing selected range is overloaded, it is required to select a higher range in order to obtain a correct reading. l In each range, the Meter has an input impedance of approx. 10MΩ. This loading effect can cause measurement errors in high impedance circuits. If the circuit impedance is less than or equal to 10kΩ, the error is negligible (0.1% or less).
Model UT90A: OPERATING MANUAL Measurement Operation(5) The measurement ranges of DC current are: 200.0µA, 2.000mA, 20.00mA, 200.0mA and 10.00A. To measure current, do the following: 1. Turn off power to the circuit. Discharge all highvoltage capacitors. 2. Insert the red test lead into the µAmA or 10A terminal and the black test lead into the COM terminal. 3. Set the rotary switch to an appropriate measurement position in A range. 4. Break the current path to be tested.
Model UT90A: OPERATING MANUAL Measurement Operation(6) D. AC Current Measurement (see figure 4) black red ( figure 4) Warning Never attempt an in-circuit current measurement where the voltage between terminals and ground is greater than 60V. If the fuse burns out during measurement, the Meter may be damaged or the operator himself may be hurt. Use proper terminals, function, and range for the measurement.
Model UT90A: OPERATING MANUAL Measurement Operation(7) E. Measuring Resistance (see figure 5) red black ( figure 5) Warning To avoid damages to the Meter or to the devices under test, disconnect circuit power and discharge all the high-voltage capacitors before measuring resistance.
Model UT90A: OPERATING MANUAL Measurement Operation(8) The resistance ranges are: 200.0 , 2.000k , 20.00k , 200.0k , 2.000M and 20.00M . To measure resistance, connect the Meter as follows: 1. Insert the red test lead into the V terminal and the black test lead into the COM terminal. 2. Set the rotary switch to an appropriate measurement position in range. 3. Connect the test leads across with the object being measured. The measured value shows on the display. Note l The test leads can add 0.1 to 0.
Model UT90A: OPERATING MANUAL Measurement Operation(9) F.Testing Diodes & Continuity Warning To avoid possible damage to the Meter and to the device under test, disconnect circuit power and discharge all high-voltage capacitors before testing diodes and continuity. Testing Diodes (see figure 6) red black ( figure 6) Use the diode test to check diodes, transistors, and other semiconductor devices.
Model UT90A: OPERATING MANUAL Measurement Operation(10) Note l l l l l l In a circuit, a good diode should still produce a forward voltage drop reading of 0.5V to 0.8V; however, the reverse voltage drop reading can vary depending on the resistance of other pathways between the probe tips. Connect the test leads to the proper terminals as said above to avoid error display. The open-circuit voltage is around 3V when testing diode. The LCD will display 1 indicating open-circuit for wrong connection.
Model UT90A: OPERATING MANUAL Measurement Operation(11) To test for continuity, connect the Meter as below: 1. Insert the red test lead into the VΩ terminal and the black test lead into the COM terminal. 2. Set the rotary switch to . 3. Connect the test leads across with the object being measured. The buzzer does not sound when the resistance value is >100Ω. The circuit is disconnected. The buzzer sounds continuously when the resistance value is 10Ω. The circuit is in good condition.
Model UT90A: OPERATING MANUAL Measurement Operation(12) Warning To avoid damages to the built-In fuse and the Meter, measure the specified battery type and power supply only. To carry out battery test, connect the Meter as follows: 1. Insert the red test lead into the µAmA . terminal and the black test lead into the COM terminal. 2. Set the rotary switch to an appropriate measurement position in range. 3.
Model UT90A: OPERATING MANUAL General Specifications(1) l Maximum Voltage between any terminals and grounding: Refer to different range input protection voltage. l Fuse Protection of µA mA terminal : 315mA, 250V, fast type, 5x20mm l l l l Fuse Protection of 10A terminal Measurement Speed Maximum Display Temperature l Relative Humidity l Altitude l Battery Type l Electro-Magnetic l l l l l l l l : 10A, 250V, fast type, 5x20mm : Updates 2-3 times /second. : 1999.
Model UT90A: OPERATING MANUAL General Specifications(2) l Safety/Compliances l Certification : IEC61010: CAT. II 1000V, CAT. III 600V overvoltage and double insulation standard.
Model UT90A: OPERATING MANUAL Accuracy Specification(1) Accuracy: (a% reading + b digits),guarantee for 1 year. o o Operating temperature:18 C~28 C. Relative humidity:<75%RH. o Temperature coefficient: 0.1 x (specified accuracy) / 1 C. A. DC Voltage Range Resolution 200mV 2V 20V 200V 1000V 0.1mV 1mV 10mV 100mV 1V Accuracy Overload Protection 230VAC (0.5%+2) 1000V DC or 750V AC rms. continuous. (0.8%+3) Remark: Input impedance: 10MΩ B.
Model UT90A: OPERATING MANUAL Accuracy Specification(2) C. DC Current Range Resolution Accuracy Overload Protection 200µA 2mA 20mA 200mA 0.1µA 1µA 10µA 0.1mA (0.8%+2) Fuse 315mA, 250V, fast type, 5x20mm 10A 10mA (1.2%+5) Fuse 10A, 250V, fast type, 5x20mm Remarks: l At 10A Range: For continuous measurement 10 seconds and interval time between 2 measurement greater than 15 minutes. D. AC Current Range Resolution Accuracy Overload Protection 200µA 2mA 20mA 200mA 0.1µA 1µA 10µA 0.1mA (1.
Model UT90A: OPERATING MANUAL Accuracy Specification(3) E. Resistance 200Ω 0.1Ω 2kΩ 20kΩ 200kΩ 2MΩ 20MΩ 1Ω 10Ω 100Ω 1kΩ 10kΩ Overload Protection Accuracy Range Resolution (0.8%+3) + short-circuit the input terminals (0.8%+3) 230V rms (1.2%+5) F. Diodes & Continuity Test Range Resolution Overload Protection 1mV 230V rms 1Ω Remarks: l At Range: Open circuit voltage approximate 3V. l At Range: Open circuit voltage approximate 3V. The buzzer does not sound when the resistance value is >100Ω.
Model UT90A: OPERATING MANUAL Maintenance(1) This section provides basic maintenance information including battery and fuse replacement instruction. Warning Do not attempt to repair or service your Meter unless you are qualified to do so and have the relevant calibration, performance test, and service information. To avoid electrical shock or damage to the Meter, do not get water inside the case. A. General Service l Periodically wipe the case with a damp cloth and mild detergent.
Model UT90A: OPERATING MANUAL Maintenance(2) Warning To avoid electrical shock or arc blast, or personal injury or damage to the Meter, use specified fuses ONLY in accordance with the following procedure. To replace the Meter’s fuse: 1. Turn the Meter off and remove all connections from the terminals. 2. Remove the holster from the Meter. 3. Remove the 3 screws from the case bottom, and separate the case top from the case bottom. 4.
Model UT90A: OPERATING MANUAL 3. Remove the 3 screws from the case bottom, and separate the case top from the case bottom. 4. Remove the battery from the battery connector. 5. Replace with a new 9V battery (NEDA1604, 6F22 or 006P). 6. Rejoin the case bottom and case top, and reinstall the 3 screws and the holster. ** END ** This operating manual is subject to change without notice.
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Model UT90A: OPERATING MANUAL Copyright 2001 Uni-Trend International Limited. All rights reserved. Manufacturer: UNI-TREND TECHNOLOGY(DONG GUAN)LIMITED Address: Dong Fang Da Dao, Bei Shan Dong Fang Industrial Development District, Hu Men Town, Dong Guan City, Guang Dong Province, China Headquarters: Uni-Trend International Limited Address: Rm901, 9/F, Nanyang Plaza 57 Hung To Road Kwun Tong Kowloon, Hong Kong Tel: (852) 2950 9168 Fax: (852) 2950 9303 Email: info@uni-trend.com http://www.uni-trend.
