Model GDM-350A: OPERATING MANUAL Table of Contents (1) Title Overview Unpacking Inspection Safety Information Rules For Safe Operation International Electrical Symbols The Meter structure Functional Buttons Measurement Operation A. DC Voltage Measurement B. AC Voltage Measurement C. DC Current Measurement D. Measuring Resistance E. Diodes and Continuity Measurement F.
Model GDM-350A: OPERATING MANUAL Table of Contents (2) Title General Specifications Accuracy Specifications A. DC Voltage B. AC Current C. DC Current D. Resistance E. Diodes and Continuity Measurement F. Temperature Maintenance A. General Service B. Replacing the Battery C.
Model GDM-350A: 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 Safety Operation” carefully before using the Meter.
Model GDM-350A: 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 Point Contact Temperature Probe 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 GDM-350A: OPERATING MANUAL Safety Information(1) Safety Information This Meter complies with the standards IEC61010: in pollution degree 2, overvoltage category (CAT I 600V, CAT II 300V) and double insulation. CAT. I: Signal level, special equipment or parts of equipment, telecommunication, electronic, etc., with smaller transient overvoltages than overvoltages CAT. II. CAT. II: Local level, appliance, PORTABLE EQUIPMENT etc., with smaller transient overvoltages than CAT.
Model GDM-350A: OPERATING MANUAL Safety Information(2) In this manual, a Warning identifies conditions and actions that pose hazards to the user, or may damage the Meter or the equipment under test.A Note identifies the information that user should pay attention on. International electrical symbols used on the Meter and in this Operating Manual are explained on page 10.
Model GDM-350A: 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 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. l Inspect the test leads for damaged insulation or exposed metal.
Model GDM-350A: OPERATING MANUAL Rules For Safe Operation (2) prevent damage of the Meter. l When the Meter working at an effective voltage over 60V in DC or 42V rms in AC, special care should be taken for there is danger of electric shock. l Use the proper terminals, function, and range for your measurements. l Do not use or store the Meter in an environment of high temperature, humidity, explosive, inflammable and strong magnetic field. The performance of the Meter may deteriorate after dampened.
Model GDM-350A: OPERATING MANUAL Rules For Safe Operation (3) l l l l l l l Remove test leads and temperature probe from the Meter and turn the Meter power off before opening the Meter case. 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.
Model GDM-350A: OPERATING MANUAL International Electrical Symbols AC or DC AC Current DC Current Earth Ground Double Insulated. Low Battery. Diode. Fuse. Continuity Test Safety Rules Conforms to Standards of European Union.
Model GDM-350A: OPERATING MANUAL The Meter Structure The Meter Structure (figure 1) 1) 2) 3) 4) 5) 6) 7) LCD Display HOLD Button Display Backlight Button Rotary Switch COM Input Terminal 10A Input Terminal Other Input Terminals (figure 1) 11
Model GDM-350A: OPERATING MANUAL Functional Buttons Below table indicated for information about the functional button operations. Button Operation Performed l Press HOLD once to enter hold mode. HOLD button l Press HOLD again to exit hold mode. l In Hold mode, H is displayed and the present value is shown. l Press BLUE button once to turn the display backlight on. BLUE button l Press BLUE button again to turn the display backlight off.
Model GDM-350A: OPERATING MANUAL Measurement Operation(1) A. DC Voltage Measurement (see figure 2) Warning To avoid harms to you or damages to the Meter from electric shock, please do not attempt to measure voltages higher than 500V although readings may be obtained. The DC Voltage ranges are: 200mV, 2000mV, 20V, 200V and 500V. To measure DC voltage, connect the Meter as follows: 1. Insert the red test lead into theVΩmAterminal and the black test lead into the COM terminal. 2.
Model GDM-350A: OPERATING MANUAL Measurement Operation (2) Note l If the value of voltage to be measured is unknown, use the maximum measurement l l l position (500V) and reduce the range step by step until a satisfactory reading is obtained. The LCD displays “1” indicating the existing selected range is overload; it is required to select a higher range in order to obtain a correct reading. In each range, the Meter has an input impedance of approx. 10MΩ.
Model GDM-350A: OPERATING MANUAL Measurement Operation (3) B. AC Voltage Measurement (see figure 2) Warning To avoid harms to you or damages to the Meter from electric shock, please do not attempt to measure voltages higher than 500Vrms although readings may be obtained. The AC voltage measurement positions are: 200V and 500V. To measure AC Voltage, connect the Meter as follows: 1. Insert the red test lead into the VΩmA terminal and the black test lead into the COM terminal. 2.
Model GDM-350A: OPERATING MANUAL Measurement Operation (4) Note l If the value of voltage to be measured is unknown, use the maximum measurement l l l position (500V) and reduce the range step by step until a satisfactory reading is obtained. The LCD displays “1” indicating the existing selected range is overload, it is required to select a higher range in order to obtain a correct reading. In each range, the Meter has an input impedance of approx. 10MΩ.
Model GDM-350A: OPERATING MANUAL Measurement Operation (5) C. DC Current Measurement (see figure 3) 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. When the testing leads are connected to the current terminals, do not parallel them across any circuit.
Model GDM-350A: OPERATING MANUAL Measurement Operation (6) The current measurement has 4 measurement positions on the rotary switch: 2000µA, 20mA, 200mA and 10A To measure current, do the following: 1. Turn off power to the circuit. Discharge all high-voltage capacitors. 2. Insert the red test lead into the VΩmA 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 GDM-350A: OPERATING MANUAL Measurement Operation (7) Note l If the value of current to be measured is unknown, use the maximum measurement position (10A) l and reduce the range step by step until a satisfactory reading is obtained. l When current measurement has been completed, disconnect the connection between the testing leads l and the circuit under test.
Model GDM-350A: OPERATING MANUAL Measurement Operation (8) D. Measuring Resistance (see figure 4) 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 GDM-350A: OPERATING MANUAL Measurement Operation (9) 1. Insert the red test lead into the VΩmA terminal and the black test lead into the COM terminal. 2. Set the rotary switch to an appropriate measurement position in Ω 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 0.1Ωto 0.3Ωof error to resistance measurement.
Model GDM-350A: OPERATING MANUAL Measurement Operation (10) between the testing leads and the circuit under test. E. Diodes and Continuity Measurement (see figure 5) Testing Diodes Warning To avoid amages to the Meter or to the devices under test, disconnect circuit power and discharge all the high-voltage capacitors before diodes. Use the diode test to check diodes, transistors, and other semiconductor devices.
Model GDM-350A: OPERATING MANUAL Measurement Operation (11) across the junction. A good silicon junction drops between 0.5V and 0.8V. To test a diode out of a circuit, connect the Meter as follows: 1. Insert the red test lead into the VΩmA terminal and the black test lead into the COM terminal. 2. Set the rotary switch to 3. For forward voltage drop readings on any semiconductor component, place the red test lead on the component’s anode and place the black test lead on the component’s cathode.
Model GDM-350A: OPERATING MANUAL Measurement Operation (12) l Connect the test leads to the proper terminals as said above to avoid error display. l The LCD will display “1” indicating open-circuit for wrong connection. The unit of diode is Volt (V), displaying the positive-connection voltage-drop value. When diode testing has been completed, disconnect the connection between the testing leads and the circuit under test. Testing for Continuity To test for continuity, connect the Meter as below: 1.
Model GDM-350A: OPERATING MANUAL Measurement Operation (13) l When continuity testing has been completed, disconnect the connection between the testing leads and the circuit under test. F. Temperature Measurement (see figure 6) Warning To avoid harms to you or damages to the Meter, please do not attempt to input voltages higher than 60V in DC or 30V in AC. o The Temperature measurement range is -40 C ~1000oC or -40oF~1832oF. To measure temperature, connect the Meter as follows: 1.
Model GDM-350A: OPERATING MANUAL Measurement Operation (14) 2. Set the rotary switch to oC or oF. 3. Place the temperature probe to the object being measured. The measured value shows on the display. Note The Meter automatically displays the temperature value inside the Meter when there is no temperature probe connection. o o l The included point contact temperature probe can only be used up to 250 C(482 F). For any measurement higher than that, the rod type temperature probe must be used instead.
Model GDM-350A: OPERATING MANUAL General Specifications(1) General Specifications l l l l l l l l Maximum Voltage (including transient overvoltage) between any Terminals and Grounding: 500V rms. Fused Protection for VΩmA Input Terminal: 315mA, 250V fast type, φ5x20 mm 10A Terminal: Un-fused. Range: Manual ranging Maximum Display: Display: 1999. Measurement Speed: Updates 2~3 times /second. Temperature: o o o o Operating: 0 C~40 C (32 F~104 F). o o o o Storage: -10 C~50 C (14 F~122 F).
Model GDM-350A: OPERATING MANUAL General Specifications(2) l l l l l l l l l Altitude:Operating: 2000 m. Storage: 10000 m. Battery Type: One piece of 9V Battery NEDA 1604 or 6F22 or 006P. Battery Deficiency: Display: . Negative reading: Display: . Overloading: Display: 1. Dimensions (HxWxL): 130 x 73.5 x 35mm. Weight: Approx. 156g (battery included). Safety/Compliances: IEC61010 CAT.I 600V overvoltage and double insulation standard.
Model GDM-350A: OPERATING MANUAL Accuracy Specifications(1) Accuracy: (a% reading + b digits), guarantee for 1 year. o o Operating temperature: 23 C 5 C. Relative humidity: <75%. o Temperature coefficient: 0.1 x (specified accuracy) / 1 C. A. DC Voltage Range 200mV 2000mV 20V 200V 500V Resolution Accuracy Overload Protection 250V DC or AC 100µV 1mV 10mV 100mV 1V (0.5%+2) 500V DC or AC (0.8%+2) Remark: Input impedance: 10MΩ.
Model GDM-350A: OPERATING MANUAL Accuracy Specifications(2) B. AC Voltage Range 200V 500V Resolution Accuracy 100mV 1V (1.2%+10) Remarks: l Input impedance: approx. 5MΩ. l Displays effective value of sine wave (mean value response). l Frequency response 40Hz ~ 400Hz.
Model GDM-350A: OPERATING MANUAL Accuracy Specifications(3) C. DC Current Range 2000µA 20mA 200mA 10A Resolution Accuracy 1µA 10µA 100µA 10mA (1%+2) (1.2%+2) (2%+5) Overload Protection 315mA, 250V fast type fuse: φ 5x20mm Un-Fused Remark: l At 10A Range: For continuous measurement 10 seconds and interval not less than 15 minutes.
Model GDM-350A: OPERATING MANUAL Accuracy Specifications(4) D. Resistance Range Resolution 200Ω 2000Ω 20kΩ 200kΩ 20MΩ 0.1Ω 1Ω 10Ω 100Ω 10kΩ Accuracy Overload Protection (0.8%+5) (0.
Model GDM-350A: OPERATING MANUAL Accuracy Specifications(5) E. Diodes and Continuity Measurement Range Resolution 1mV 1Ω Remark Displays approximate forward voltage drop: 0.5V~0.8V. Buzzer beeps at <70Ω Overload Protection 250V DC or AC F. The Model GDM-350A: Temperature Range o o -40 C~150 C o o 150 C~1000 C -40oF~302oF 302oF~1832oF Resolution o 1C o 1F Remark (1%+7) (1.5%+15) (1%+10) (1.
Model GDM-350A: 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 GDM-350A: OPERATING MANUAL Maintenance(2) l Do not store the Meter in a place of humidity, high temperature, explosive, inflammable and strong magnetic field. B. Replacing the Battery (see figure 8) 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. Screw To replace the battery: 1.
Model GDM-350A: OPERATING MANUAL Maintenance(3) 2. Turn the Meter to OFF position. 3. Remove the screw from case bottom, and separate the case bottom from the case top. 4. Remove the battery from the battery compartment. 5. Replace the battery with a new 9V battery (NEDA 1604 or 6F22 or 006P). 6. Rejoin the case bottom and case top, and reinstall the screw. C.
Model GDM-350A: OPERATING MANUAL Maintenance(4) 3. 4. 5. 6. Remove the screw from case bottom, and separate the case bottom from the case top. Remove the fuse by gently prying one end loose, and then take out the fuse from its bracket. Install ONLY replacement fuses with the identical type and specification as follows and make sure the fuse is fixed firmly in the bracket. 315mA, 250V, fast type, φ 5x20mm. Rejoin the case bottom and case top, and reinstall the screw.
