GDM-8245 User Manual
Contents
1. DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 7 RESISTANCE 500K J 109 0 1912 1000 0 2 2 2M9 Q 0 3 2 Open circuit Voltage 3 2 volts maximum on 500 Q 1 3 volts maximum on all other ranges Protection 450V dc or peak ac continuous 8 CAPACITANCE 0 001n 2 InF 2 10 OOOO eee 0 01n 2 10nF 2 10 i eee a Ee o 5n range tends to be interfered by the test lead s impedance and position For the accuracy please measure the range on the input terminal directly Protection 450V dc or peak ac continuous 9 DIODE CHECK Description Display read forward voltage of diode Open Voltage 3 1V approx Maximum Forward Voltage 1 5V Protection 450V dc or peak ac continuous DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 10 CONTINUITY BEEPER Description Built in buzzer sounds if conductance is less than 5 ohm Open Voltage 3 volts maximum Protection 450V dc or peak ac continuous 11 ENVIRONMENTAL Indoor use altitude up to 2000m Ambient Temperature 0 C to 50 C Relative Humidity 75 Maximum Installation category H Pollution Degree 2 Operation Environment Storage temperature 40 C to 70 C Up to 75 0 C to 35 C Up to 50 35 C to 50 C except Relative Humidity the ranges of 2MQ and 20MQ which are up to 75 0 C to 35 C 12 GENERAL Maximum C2. of over range indication 3 FREQUENCY MEASUREMENT AT ACV RANGE FREQUENCY INPUT LEVEL SINE WAVE 500mV 10Hz 50kHz gt 120mV Pe 50k 150kHz 200mV 10Hz 200kHz 1 2V 20Hz 200K 20Hz 1kHz gt 12V Maximum Input 450V peak ac continuous on 500mV range 500V peak ac continuous on the other range 4 DC Current RESOLUTION DOHA Sma EZE EZE DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 500 uw A 5mA 50mA 500mA 2A 5 ranges fuse protection 20A range no fuse 15 seconds max When the input exceeds the full scale of the selected range the display will appear OL of over range indication 5 TRUE RMS AC OR AC DC CURRENT Protection Accuracy Between 2 of range and full range RANGE 20Hz 45Hz 45Hz 2kHz 2kHz 10kHz 10kHz 20kHz 5004 A 1 15 0 5 15 1 15 2 15 5mA 1 15 0 5 15 1 15 2 15 SOS A E SS E E 500 uw A 5mA 50mA 500mA 2A 5 ranges fuse protection 20A range no fuse 15 seconds max Protection Crest Factor Range 3 0 at full scale The burden voltage is the same as the DC current When the input exceeds the full scale of the selected range the display will appear OL of over range indication 6 FREQUENCY MEASUREMENT AT ACA RANGE RANGE FREQUENCY INPUT LEVEL SINE WAVE ACCURACY 500 w A 10Hz 20kHz 0 05 1 0 05 1 0 05 1 0 05 1 A AC DC measurement does not support AC Hz function
3. installation DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL DANGER High Voltage ATTENTION refer to Manual Protective Conductor Terminal IF e amp ground Earth Terminal Frame or Chassis Terminal DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL FOR UNITED KINGDOM ONLY NOTE This lead appliance must only be wired by competent persons WARNING THIS APPLIANCE MUST BE EARTHED IMPORTANT The wires in this lead are coloured in accordance with the following code Green Yellow Earth Blue Neutral Brown Live Phase As the colours of the wires in main leads may not correspond with the colours marking identified in your plug appliance proceed as follows The wire which is coloured Green amp Yellow must be connected to the Earth terminal marked with the letter E or by the earth symbol D or coloured Green or Green amp Yellow The wire which is coloured Blue must be connected to the DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL terminal which is marked with the letter N or coloured Blue or Black The wire which is coloured Brown must be connected to the terminal marked with the letter L or P or coloured Brown or Red If in doubt consult the instructions provided with the equipment or contact the supplier This cable appliance should be protected by a suitably rated and approved HBC mains fuse refer to the rating information on the equipment and or user instructions for details As a guide c
4. DC 500mV 450V dc or ac peak OHM all ranges 450V dc or ac peak CAPACITANCE all ranges 450V dc or ac peak WARNING To avoid shock hazard and or instrument damage do not apply input potentials that exceed the input overload limits shown in table 4 1 4 7 Input connections to common do not connect the common input terminal to any source of WARNING To avoid shock hazard and or instrument damage more than 500 volts DC or peak AC above earth ground DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 5 MEASUREMENT TUTORIAL 5 1 Voltage measurements DCV ACV DCmV ACmV 1 Press the button to select desired function 2 Press A Jor W to the desired range if you have no idea about the value of input we suggest you always start at the highest range Press AUTO MAN button for manual or auto ranging selection 3 Connect the test lead to the V and COM input terminals of the instrument 4 Connect the test lead to the measuring points and read the displayed value NOTE After measuring high voltage to 1000V dc errors may occur when the 100 v V is measured Allow up to one minute prior to making low level measurements 5 2 Current measurements DCA DC 20A ACA AC 20A 1 Press the button to select function 2 Press A or W to the desired range if you have no idea about the value of input we suggest you always start at the highest range Press AUTO MAN button to change manual or auto ranging 3 Connect
5. Declaration of Conformity We DUAL DISPLAY DIGITAL GOOD WILL INSTRUMENT CO LTD No 7 1 Jhongsing Rd Tucheng City Taipei County 236 Taiwan D WILL INSTRUMENT ZH LTD MULTIMETER GOOD W NSTRUMENT SUZHOU CO No 69 Lushan Road Suzhou New District Jiangsu China declares that the below mentioned product MODEL GDM 8245 GDM 8245 is herewith confirmed to comply with the requirements set out in the Council Directive on the Approximation of the Law of Member States relating to Electromagnetic Compatibility 89 336 EEC 92 31 EEC 93 68 EEC and Low Voltage Equipment Directive 73 23 EEC 93 68 EEC For the evaluation regarding the Electromagnetic Compatibility and Low Voltage Equipment Directive the following standards were applied EMC User Man ual EN 61326 1 Electrical equipment for measurement control and laboratory use EMC requirements 1997 A1 1998 GW INSTEK Good Will Instrument Co Ltd GW Part No 82DM 82450MI Conducted and Radiated Emissions EN55011 Group II class B 1998 Electrostatic Discharge EN 61000 4 2 1995 Current Harmonic Radiated Immunity EN 61000 3 2 1995 EN 61000 4 3 1996 Voltage Fluctuation Electrical Fast Transients EN 61000 3 3 1995 EN 61000 4 4 1995 n urge Immunity N 61000 4 5 1995 ies Q onducted Susceptibility N 61000 4 6 1996 m Safety ltage Dips Interrupts N 61000 4 11 1994 m Low Voltage Equip
6. MAX MIN mode 5 9 REL measurements When the REL button is pressed the meter stores the present reading and displays subsequent measurements as the difference between the measured value and the stored reading In the MAX MIN mode set REL button to the REL mode The maximum or minimum reading will become the relative base 5 10 HOLD measurements The HOLD mode that allows you to keep your eyes fixing on the probes when taking measurements in difficult or hazardous circumstances then read the display when it is convenient and safe Press the HOLD button the last reading is held on the display in all function To release the HOLD function press HOLD again 17 DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 6 MEASUREMENT TECHNIQUES 6 1 dBm measurement technique dBm is defined as above or below a ImW reference A voltage measurement is converted to dBm using the following formula dBm 10 log 1000 voltage value reference impedance The standard reference impedance of the instrument is 600 Q For example 0 7746V will be convert to 0 dBm 6 2 True rms measurement The true rms root mean square value of a waveform is equivalent to dc value that causes the same amount of heat to be dissipated in a resistor Since average responding meters have been in use for so long you may have accumulated test or reference data based on them Figure 6 1 illustrates the relationship between ac and dc components for common wav
7. The dBm mode and AC Hz mode are not selected concurrently The standard reference impedance of the instrument is 6002 5 6 AC Hz measurements The function can be selected only when ac range is selected Press SHIFT then press AC Hz the secondary display shows the frequency of the input signal that is higher than the sensitivity The frequency measurement does not depend on the max min rel or hold mode In this mode the reading rate of the DMM may be slower than the normal state To release the AC Hz function press AC Hz again The dBm mode and AC Hz mode are not selected concurrently 5 7 AC DC measurements The function can be selected only when voltage or current function is selected Press AC DC button the primary display shows the true rms value of the input signal including the ac component and dc component In this mode the reading rate of the DMM is slower than the normal state To release the AC DC function press other function voltage ac or dc current ac or dc R C Continuity Beeper Diode Test key 16 DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 5 8 MAX MIN measurements The MAX MIN mode causes the DMM to hold the lowest and highest readings Press MAX MIN button to the MAX mode The highest will be displayed in continuous input In the MAX mode press MAX MIN button to the MIN mode The lowest will be displayed in continuous input In the MIN mode press MAX MIN button to release the
8. able of 0 75mm2 should be protected by a 3A or 5A fuse Larger conductors would normally require 13A types depending on the connection method used Any moulded mains connector that requires removal replacement must be destroyed by removal of any fuse amp fuse carrier and disposed of immediately as a plug with bared wires is hazardous if a engaged in live socket Any re wiring must be carried out in accordance with the information detailed on this label DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 2 INTRODUCTION This instrument is a portable bench type dual display digital multimeter with a good performance 50000 counts designed for general purpose application The dual display allows you to display two functions of the input signal being measured Features 50000 counts DMM Multi function ACV DCV ACA DCA R C Hz Continuity Beeper Diode Test MAX MIN REL HOLD dBm Dual display Indicate ACV and Hz or DCV ACV and dBm Manual or Autoranging 0 03 DCV accuracy 20A high current range 1000V high voltage range AC True RMS or AC DC True RMS DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 3 SPECIFICATIONS The specifications are operated under the essential conditions as follows A 1 year calibration cycle An operating temperature of 18 to 28 C 64 4 to 82 4 F Relative humidity not exceeding 75 The AC specification is based on the 50 of duty cycle e e e Accuracy is expressed as pe
9. aveforms in Figure 6 2 show signals with increasing value of crest factor As you can see from the series of waveforms a signal with a crest factor above 3 0 is unusual DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL Figure 6 2 Crest Factor WAVEFORM SOURARE WAVE SINE WAVE TRIANGLE SAWTOOTH Ay MIXED FREQUENCIES SCR OUTPUT OF 100 10 WHITE NOISE KNAW AC COUPLED PULSE TRAIN i CREST FACTOR 1 414 to 2 0 1 414 to 3 0 3 0 to 4 0 21 DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 7 MAINTENANCE The following instructions are executed by qualified personnel only To avoid electrical shock do not perform any servicing other than the operating instructions unless you are qualified to do so 7 1 Line fuse replacement If the fuse blows the DMM would not work Try to determine and correct the cause of the blown fuse then replace the fuse with correct rating and type shown as below FUSE RATING AND TYPE 100 120V TO 1A 250V 230V T0 08A 250V F101 on PCB TO 5A 250V 7 2 Current fuse replacement The current fuse protects the 500 4 A 2A range from an input current greater 2A To replace the current fuse perform the following steps 1 Turn off the power disconnect the power line and remove the test leads 2 Place the end of a flat blade screwdriver into the slot of the fuse holder on the front panel Push and carefully rotate the fus
10. e carrier turn counterclockwise till remove the fuse and the fuse carrier off the front panel 3 Remove the defective fuse and replace the correct fuse F2A 250V DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 7 3 Line voltage conversion The primary winding of the power transformer is tapped to permit operation from 100 120V or 230V AC 50 60Hz line voltage Conversion from one line voltage to another is done by changing the line voltage selector switch as shown in Figure 4 2 The rear panel identifies the line voltage to which the unit was factory set To convert to a different line voltage perform the following procedure 1 Make sure the power cord is unplugged 2 Adjust the line voltage selector switch to the desired line voltage position 3 A change in line voltage may also require a corresponding change of fuse value Install the correct fuse value as listed on rear panel 7 4 Cleaning To keep the instrument clean wipe the case with a damp cloth and detergent Do not use abrasives or solvents 23
11. eforms and compares readings for true rms meters and average responding meters Figure 6 1 will help you convert between the two measurement methods DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL Figure 6 1 Voltage Conversion DC AND AC TOTAL RMS AC COMPONENT ac COMPONENT ONLY _ enh GA AC siniecuter t TRUE RMS ONLY AC COUPLED INPUT WAVEFORM RECTIFIED SINE FULL WAVE ENNE 2 Y Pere o RECTIFIED SINE HALF WAVE RECTIFIED SOUARE PKPK gig 2 5 RECTANGULAR PULSE ia x PKPK y le F D xiy K V DD TRIANGLE SAWTOOTH PK 0 PKPK RMS CAL IS THE DISPLAYEO VALUE FOR AVERAGE RESPONDING METERS THAT ARE CALIBRATED TO DISPLAY RMS FOR SINE WAVES Your Digital Multimeter 19 DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 6 3 AC DC measurement A signal includes an ac component and a dc level The relationship between the total rms value of the signal and the ac component and the dc component is rms total ac component rms de component 6 4 Crest factor Crest factor is often overlooked in determining the accuracy of an ac measurement Crest factor is defined as the ratio of the peak signal amplitude to the rms value of the signal If an input signal has a crest factor of 3 0 or less voltage measurements will not be in error due to dynamic range limitations at full scale The w
12. ment Directive 73 23 EEC amp amended by 93 68 EEC IEC EN 61010 1 2001 DUAL DISPLAY DIGITAL MULTIMETER DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL USER MANUAL TABLE OF CONTENTS PAGE 1 SAFETY SUMMARY 1 SAFETY SUMMARY ccccccscsecsecccsccnccecscescsseessceees 1 Please take a moment to review these safety terms and symbols which may appear in this manual or on Equipment to prevent 2 INTRODUCTION scissioni sassinoro 5 damage to the instrument 3 SPECIFICATION scscccscccscsccscccccccccccscsescecscececes 6 4 OPERATION INSTRUCTION cccecessccseccscsesceceees 11 WARNING Warning statements identify condition or 5 MEASUREMENT TUTORIAL cccecscscscecsceccscseees 14 practices that could result in injury or loss of life 6 MEASUREMENT TECHNIQUEG ccccccccscccscccecececeees 18 7 MAINTENANCE 0cccsscsccssccsccscesccsscscescessesceesees sess 22 CAUTION Caution statements identify conditions or practices that could result in damage to this product or other property Measurement category I is for measurements performed on circuits not directly connected to MAINS Measurement category II is for measurements performed on circuits directly connected to the low voltage installation Measurement category III is for measurements performed in the building installation Measurement category IV is for measurements performed at the source of the low voltage
13. n An input is over range if it exceeds the full scale of the selected range GDM 87245 indicates an input is over range by lighting the OL pattern on display 4 5 No specification indication On AC Hz measured mode when an input is less sensitivity the secondary display show When the frequency of an input exceeds 51kHz the primary display will show DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL Figure 4 1 Front Panel Secondary Display Primary Display Input Terminals ae pa g M I of oO 3786F B B A 88 HMT g m MOD MAX MIN AMO oc AG REL Mb o 98rT sazz 1200v CAT T soov CATH va Demy ACTV HEDDA CC20A AUDA AC HI gam arn OES GWINSTEK GDM 8245 Push Buttons Figure 4 2 Rear Panel Line Voltage Selector and Input Fuse Holder 12 AC Power Line Connector DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 4 6 Input overload protection The maximum allowable input is shown as table 4 1 Please proceed the measurement accordingly Table 4 1 FUNCTION RANGE MAXIMUN INPUT DCV 5V 1000V 1000Vdc or peak ac ACV AC DC 5V 1000V 1000V rms continuous amp 10 VeHz maximum DCA ACA AC DC 500 4 A 2A fuse protected 2A 250V DC AC20A AC DC 20A no fuse protected DC ACmV AC
14. ommon 500V dc or peak ac low terminal potential with Mode Voltage respect to power line ground Warm Up 0 5 hours to achieve rated accuracy Power source AC 100V 120V 230V 15 50 60Hz 8 0VA 6 0W Accessories Test Lead x1 Instruction manual x 1 Dimension 251 W x91 H x291 D m m Weigh Approx 2 6 kg WARNING To avoid electrical shock the power cord protective grounding conductor must be connected to gt ground CAUTION To avoid damaging the instrument do not use gt it in a place where ambient temperature exceeds 50 C DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 4 OPERATION INSTRUCTIONS 4 1 Front panel and rear panel The front panel shown in Figure4 1 contains three main elements the input terminals the primary and secondary displays and the push buttons The rear panel shown in Figure 4 2 contains the AC power line connector and fuse amp line voltage selector and input fuse holder 4 2 The SHIFT key and function keys SHIFT button is used to enable the secondary function of certain function keys that with blue symbols printed above The SHIFT LED will be on after pressed the SHIFT button At this time only the buttons with blue symbols are workable To release SHIFT function press SHIFT again For example to select DCmV function press SHIFT then press DCV DCmV 4 3 Warm up The instrument requires half an hour warm up to achieve rated accuracy 4 4 Over range indicatio
15. rcentage of reading digits 1 DC VOLTAGE RANGE _ RESOLUTION ACCURACY INPUT IMPEDANCE 500mV 10uV 10MQ 1004 V 11 1 MQ 0 03 4 10 1MQ 500V 10M9 1000V 100mV 0 03 9 10MQ Input Impedance Approx 10MQ in parallel with lt 100pF all ranges Normal Mode Rejection Ratio gt 60dB at 60Hz or 50Hz Common Mode Rejection Ratio gt 90dB at 60Hz or 50Hz Common Mode Voltage Max 500V dc or peak ac 450V dc or peak ac continuous on 500mV range Maxi Input cara ete 1000V dc or peak ac continuous on other range dBm ref 6002 63 80 dBm 97 7 dBm When the input exceeds the full scale of the selected range the display will appear _OL of over range indication 2 TRUE RMS AC OR AC DC VOLTAGE Accuracy between 2 of range and full range 45Hz 1kHz 2kHz 10kHz 20kHz 50kHz 500V_ _1 15 asra _ 1oo0v 1 15 Jos eis5 ___f DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL RESOLUTION INPUT IMPEDANCE 10uV 10MQ 100 u V 11 MQ ImV 10 1MQ 10MQ 100mV 10MQ Input Impedance Approx 1OM Q in parallel with lt 100pKall ranges 450V dc or peak ac continuous on 500mV range 1000V rms on other range dBm ref 600Q 63 8dBm 97 7dBm Crest Factor Range 3 0 at full scale When the input exceeds the full scale of the selected range the display will appear Maximum Input _OL
16. the test lead to the 2A or 20A and COM input terminals of the instrument 4 Connect the test lead to the measuring points and read the displayed value 14 DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 5 3 Resistance capacitance continuity beeper measurements 1 Press the button to select function 2 Press A Jor W to the desired range Press AUTO MAN button to change manual or auto ranging 3 Connect the test lead to the Q 4 and COM input terminals of the instrument 4 Connect the test lead to the measuring points and read the displayed value 5 4 Diode test measurements 1 Press the button to select function 2 Connect the test lead to the r and COM input terminals of the instrument 3 Connect the test lead to the semiconductor junction diode or transistor as shown in Figure 5 1 and read the displayed value Figure 5 1 Connect to Connect to c r COM terminal terminal 5 5 dBm measurements This function converts a voltage measurement into dBm The function can be selected only when a voltage function volts ac volts dc or volts actdc is selected Press dBm button the secondary display shows the dBm value that reposed on the voltage value showed in the primary display 15 DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL For example if dBm is pressed when measuring voltage in the max mode the maximum value is converted to dBm To release the dBm function press dBm again
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