GDM-356 Table of Contents Page Title Overview Unpacking Inspection Safety Information Rules For Safe Operation International Electrical Symbols The multimeter Structure Functional Buttons Display Symbols Measurement Operation A. DC Voltage Measurement B. AC Voltage Measurement C. DC Current Measurement D. AC Current Measurement E. Measuring Resistance F. Frequency Measurement G. Temperature Measurement H. Capacitance Measurement I.
GDM-356 Title E. F. G. H. I. Page Resistance Test Frequency Temperature Capacitance Diodes and Continuity Test Maintenance A. B. C.
GDM-356 Overview Warning To avoid electric shock or personal injury, read the "Safety Information" and "Rules for Safe Operation" carefully before using the Meter. Digital Multimeters Model GDM-356 (hereafter referred to as “the Meter”) are 3 1/2 digits with steady operations, fashionable structure and highly reliable hand-held measuring instrument. The Meter uses large scale of integrated circuit with double integrated A/D converter as its core and has full range overload protection.
GDM-356 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 Test Clip Point Contact Temperature Probe Qty 1 piece 1 pair 1 pair 1 piece In the event you find any missing or damage, please contact your dealer immediately.
GDM-356 Safety Information This Meter complies with the 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 voltage overvoltages than CAT. III CAT. III: Distribution level, fixed installation, with smaller transient overvoltages than CAT. IV Use the Meter only as specified in this operating manual, otherwise the protection provided by the Meter may be impaired.
GDM-356 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 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. Inspect the test leads for damaged insulation or exposed metal.
GDM-356 Rules For Safe Operation (2) l Disconnect circuit power and discharge all highvoltage capacitors before testing resistance, continuity, diodes, capacitance or current. l Before measuring current, check the Meter’s fuses and turn off power to the circuit before connecting the Meter to the circuit. l Replace the battery as soon as the battery indicator appears. With a low battery, the Meter might produce false readings that can lead to electric shock and personal injury.
GDM-356 International Electrical Symbols AC (Alternating Current). DC (Direct Current). AC or DC. Grounding. Double Insulated. Deficiency of Built-In Battery. Continuity Test. Diode. Capacitance Test. Fuse. Warning. Refer to the Operating Manual. Conforms to Standards of European Union.
GDM-356 The multimeter Structure (see figure 1) ( figure 1) 9
GDM-356 Functional Buttons Below table indicated for information about the functional button operations Button Operation Performed POWER (Yellow Button) HOLD (Blue Button) 10
GDM-356 Display Symbols (see figure 2) ( figure 2) No. 1 2 3 4 5 6 7 8 9 10 11 Symbol Meaning Dangerous Voltages. 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. Indicator for AC voltage or current.The displayed value is the mean value. Indicates negative reading. Test of diode. Data hold is active. The continuity buzzer is on.
GDM-356 Display Symbols (see figure 2) No. 12 13 14 Symbol nF, µF Meaning F: Farad. The unit of capacitance. µF: Microfarad.1 x 10-6 or 0.000001 farads. nF: Nanofarad. 1 x 10-9 or 0.000000001 farads. The unit of frequency in cycles/ kHz second. Kilohertz. 1 x 10-3 or 1,000 hertz. 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.
Measurement Operation(1) A. DC Voltage Measurement (see figure 3) ( 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 or 750V rms although readings may be obtained. The DC Voltage ranges are: 200mV, 2V, 20V, 200V and 1000V.
GDM-356 Measurement Operation(2) Note l If the value of voltage to be measured is unknown, use the maximum measurement position (1000V) and reduce the range step by step until a satisfactory reading is obtained. 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. 10MΩThis loading effect can cause measurement errors in high impedance circuits.
GDM-356 Measurement Operation(3) The AC voltage measurement has 4 measurement positions on the rotary switch: 2V, 20V, 200V and 750V To measure AC Voltage, connect the Meter as follows: 1. 2. 3. Insert the red test lead into the VΩ terminal and the black test lead into the COM terminal. Set the rotary switch to an appropriate measurement position in V range. Connect the test leads across with the object being measured.
GDM-356 Measurement Operation(4) C. DC Current Measurement (see figure 5) ( figure 5) Warning Never attempt an in-circuit current measurement where the open circuit voltage between terminals and ground is greater than 60V DC or 30V rms. 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.
GDM-356 Measurement Operation(5) 2. Insert the red test lead into the µAmA or 20A 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. Connect the red test lead to the more positive side of the break and the black test lead to the more negative side of the break. 5. Turn on power to the circuit. The measured value shows on the display.
GDM-356 Measurement Operation(6) 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.
GDM-356 Measurement Operation(7) E. Measuring Resistance (see figure 7) red black ( figure 7) 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. The resistance ranges are: 200Ω, 2kΩ, 20kΩ, 200kΩ, 2MΩ and 200MΩ. To measure resistance, connect the Meter as follows: 1. Insert the red test lead into the VΩ terminal and the black test lead into the COM terminal. 2.
GDM-356 Measurement Operation(8) measured resistance value (Y) – (X) = precision readings of resistance. l For high resistance (>1MΩ), it is normal taking several seconds to obtain a stable reading. l When there is no input, for example in open circuit condition, the Meter displays “1”. l When resistance measurement has been completed, disconnect the connection between the testing leads and the circuit under test. F.
GDM-356 Measurement Operation(9) Note l When Hz measurement has been completed, disconnect the connection between the testing leads and the circuit under test. G. Temperature Measurement (see figure 9) ( figure 9) Warning To avoid harm to you or damages to the Meter, do not attempt to measure voltages higher than 60V in DC or 30V rms in AC although readings may be obtained. o The temperature measurement range is from -40 C~ o o o 1000 C or -40 F~1832 F.
GDM-356 Measurement Operation(10) l The included temperature probe can only be measured o up to 250 C For any mesaurement higher than that, the rod type temperature probe must be used instead. l When temperature measeuremnet has been completed, disconnect the connection between the testing leads and te circuit under test. H.Capacitance Measurement (see figure 10) ( figure 10) Capacitance measurement has 4 measurement positions on the rotary switch: 20nF, 200nF, 2µF and 100µF.
GDM-356 Measurement Operation(11) Note l For testing the capacitor with polarity, connect the red test lead to anode & black test lead to cathode l When the tested capacitor is shorted or the capacitor value is overloaded, the LCD display “1”. l To minimize the measurement error caused by the distributed capacitor, the testing lead or testing clip should be as short as possible. When the tested capacitor is greater than 30 µF, reading is for reference only.
GDM-356 Measurement Operation(12) Note 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. l Connect the test leads to the proper terminals as said above to avoid error display. The LCD will display “1” indicating open-circuit for wrong connection. The unit of diode is Volt (V), displaying the positiveconnection voltage-drop value.
GDM-356 Sleep Mode Turning on the Auto Display Backlight The Meter has a built-in sensor. Therefore the Display Backlight turns on and off automatically depending on the brightness of the environment. In a dim condition, the Display Backlight turns on automatically while in a bright condition, the Display Backlight turns off automatically.
GDM-356 General Specifications l l l l l l l l l l l l l l l l l l Maximum voltage between any Terminals and Grounding : 1000V rms. Fused Protection for mA Input Terminal : 0.5A, 250V fast type, 5x20mm. Fused Protection for 20A Input Terminal : Un-fused. Range : Manual ranging. Maximum Display : Display :1999. Mesaurement Speed : Updates 2~3 times/second. o o Temperature : Operating: 0 C~40 C o o (32 F~104 F); o o o o Storage : -10 C~50 C( 14 F~122 F).
GDM-356 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 Resolution 200mV 100µV 2V 20V 200V 1000V 1mV 10mV 100mV 1V Accuracy (0.5%+1) (0.8%+2) Overload Protection 250VDCor ACrms. 1000V DC or 750V AC rms. Remark: Input impedance: 10MΩ B. AC Voltage Range Resolution 2V 20V 200V 750V 1mV 10mV 100mV 1V Accuracy (0.8%+3) (1.
GDM-356 Accuracy Specifications(2) C. DC Current Range Resolution 20mA 10µA 200mA 100µA 10mA 20A Accuracy (0.8%+1) (1.5%+1) (2%+5) Overload Protection 0.5A. 250V fast type fuse, 5x20 mm Un-Fused Remarks: l At 20A Range: For continuous measurement 10 seconds and interval not less than 15 minutes. l Measurement voltage drop: Full range at 200mV. D. AC Current Range Resolution Accuracy 20mA 10µA (1%+3) 200mA 20A 100µA 10mA (1.8%+3) (3%+5) Overload Protection 0.5A.
GDM-356 Accuracy Specifications(3) E. Resistance Test Accuracy Range Resolution 0.1Ω 1Ω 10Ω 100Ω 1kΩ 100kΩ 200Ω 2kΩ 20kΩ 200kΩ 2MΩ 200MΩ Overload Protection (0.8%+3) (0.8%+1) 250V DC or AC rms [5%(reading-10)+10] Remarks: l Open circuit voltage: 700mV (At 200MΩ range, it is approx. 2.8V) l At 200MΩ range , test lead is in short circuit , and it is normal to display 10 digits. During measurement, subtract the 10 digits from the reading. F.
GDM-356 Accuracy Specifications(4) H. Capacitance Range Resolution 20nF 200nF 2µF 100µF 10pF 0.1nF 1nF 0.1µF Accuracy (4%+3) Overload Protection 250V AC (4%+3) (5%+4) Remarks:Testing signal:approx. 400Hz 40mV rms. When the tested capacitor is greater than 30 µF, reading is for reference only. I. Diodes and Continuity Test Range Resolution Input Protection 1mV 250V DC or AC 1Ω 30 Remark Open circuit voltage approx.2.
GDM-356 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 damp cloth and mild detergent. Do not use chemical solvent.
GDM-356 Maintenance(2) Warning To avoid false readings, which could lead to possible electric shock or personal injury,replace the battery as soon as the battery indicator To replace battery: 1. 2. 3. 4. 5. 6. appears. Disconnect the connection between the testing leads and the circuit under test, and remove the testing leads away from the input terminals of the Meter.
GDM-356 Maintenance(3) 1. Install ONLY replacement fuses with the identical type and specification as follows and make sure the fuse is fixed firmly in the bracket. 0.5A. 250V fast type fuse, φ5x 20mm. 2. Rejoin the case bottom and the case top, and install the screw and rubber feet Replacement of fuses is seldom required. Burning of a fuse always results from the improper operation. ~ END ~ This operating manual is subject to change without notice.
