DUAL DISPLAY DIGITAL MULTIMETER MODEL: GDM
Contents
1. E un S Un S z gt et When the input exceeds the full scale of the selected range the display will appear OL of over range indication ej Q 2 e lt w gt Un e 2 gt gt A gt 2 gt RANGE FREQUENCY INPUT LEVEL SINE WAVE 500p A 10Hz 20kHz 5mA 10Hz 20kHz 50 10Hz 20kHz 2 mA 500mA A gt 0 05 1 20A 9A 0 05 1 0 059641 0 059641 0 059641 0 059641 z IV SJS SIE S gt IV 4 IV gt 2 D e ga IV DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL RANGE 5000 soa 500K0 5kQ 5MQ 1000 0 2062 20 0 0 35042 Protection RANGE 0 001n InF 2 10 0 01n 10nF 2 10 aoe 5n 50n 500n Su m Sid 50u gt Q 3 c ga Oo NO lt Un z gt lt d c d O gt 9 m 95 lt Un d d c O D et In 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 Description Voltage Protection 450V dc or peak ac continuous DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 10 CONTINUITY BEEPER Built in buzzer2. 250V of fuse value Install the correct fuse value as listed on rear panel 230V T0 08A 250V 7 4 Cleanin 101 on PCB 0 5 250V To keep the instrument clean wipe the case with a damp cloth detergent Do not use abrasives or solvents 7 2 Current fuse replacement 5 The current fuse protects 5001 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 fuse 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 250 22 23
3. 0 707 D RECTANGULAR PULSE 2 000 nz x PK PK ve 2 6 TRIANGLE 1 SAWTOOTH PK ow 0 af PK PK RMS CAL 15 THE OISPLAYED VALUE FOR AVERAGE RESPONDING METERS THAT ARE CALIBRATED DISPLAY RMS FOR SINE WAVES Your Digits Multimeter 19 DUAL DISPLAY DIGITAL MULTIMETER DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL USER MANUAL Figure 6 2 Crest Factor 6 3 AC DC measurement A signal includes an ac component and a dc level The relationship WAVEFORM CREST FACTOR between the total rms value of the signal and the ac component and the dc component is WAVE rms total component rms dc component SIME WAVE AV 6 4 Crest factor TRIANGLE 1312 Crest factor is often overlooked in determining the accuracy of an ac SAWTOOTH 29 measurement Crest factor is defined as the ratio of the peak signal amplitude to the rms value of the signal zoo RR 1 414 20 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 OUTPUT fu i4 310 full scale xiii A p waveforms Figure 6 2 show signals with increasing value of MAMMA crest factor As you can see from the series of waveforms a signal with vid a crest factor above 3 0 1s unusual AC COUPLED PULSE TRAIN DUAL DISPLAY DIGITAL MULTIMETER US
4. VOLTAGE Accuracy between 2 of range and full range 45Hz 1kHz 2kHz 10kHz 20kHz 50kHz 19915 A 1000v 1 15 0 5 15 3 DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL RANGE RESOLUTION 500mV 5V Ov 5007 10007 vem 1000V rms on other range Bm ref 6000 Crest Factor Range When the input exceeds the full scale of the selected range the display will appear OL of over range indication 3 FREQUENCY MEASUREMENT AT ACV RANGE OM sois UV Maximum Input 450V peak ac continuous on 500mV range 500V peak ac continuous on the other range 4 DC Current RANGE RESOLUTION ACCURACY BURDEN VOLTAGE 500u A 0 0lu A 0 2 2 OWA 029902 DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 500u A 5mA 50mA 500mA 24A 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 Between 2 of range and full range Protection mA 500mA 1904 15 0 59615 2 1 15 0 5 15 20A 1 15 0 5 15 500u A 5mA 50mA 500mA 24A 5 ranges fuse protection 20A range no fuse 15 seconds max 3 0 at full scale Q F o g AB 2 eis ew z UG 2 5 C lt goa
5. be displayed in continuous input In the MIN mode press MAX MIN button to release the 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 DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL USER MANUAL 6 MEASUREMENT TECHNIQUES Figure 6 1 Voltage Conversion Poem LT ae 6 1 dBm measurement technique dBm is defined as above or below a 1mW reference voltage PRESSE measurement is converted to dBm using the following formula EN Lana dBm 10 log jo 1000 voltage value reference impedance yee The standard reference impedance of the instrument is 6000 Nd For example 0 7746V will be convert to 0 dBm nn ES px d E 6 2 True rms measurement hei The true rms root mean square value of a w
6. DUAL DISPLAY DIGITAL MULTIMETER MODEL GDM 8245 User Manual Good Will Instrument Co Ltd GW Part No 82DM 82450MD Printed in Taiwan December 2003 Declaration of Conformity We GOOD WILL INSTRUMENT CO LTD No 95 11 Pao Chung Rd Hsin Tien City Taipei Hsien Taiwan GOOD WILL INSTRUMENT SUZHOU CO LTD No 69 Lushan Road Suzhou New District Jiangsu China declares that the below mentioned product 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 EN 61326 1 Electrical equipment for measurement control and laboratory use EMC requirements 1997 A1 1998 Conducted and Radiated Emissions ee ares EN 61000 4 6 1996 Voltage Dips Interrupts 00 T ero ____ Safety Low Voltage Equipment Directive 73 23 EEC amp amended by 93 68 EEC EN 61010 1 2001 IEC 61010 1 2001 DUAL DISPLAY DIGITAL MULTIMETER DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL USER MANUAL TABLE OF CONTENTS PAGE 1 SAFETY SUMMARY I SAFETY SUMMARY etre ori Er a deb E Vea 1 Please take a moment to review these safety terms and sym
7. ER MANUAL T Figure 6 2 Crest Factor WAVEFORM CREST FACTOR SOURARE WAVE 1 0 SINE WAVE 1 414 TRIANGLE SAWTOOTH 1 732 MIXED rreauencies A 1 414 to 2 0 SCR OUTPUT OF 100 10 1 414 to 3 0 WHITE NOISE NAA 3 0 to 4 0 AC COUPLED 30 PULSE TRAIN SPIKE gt 90 DUAL DISPLAY DIGITAL MULTIMETER DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL USER MANUAL 7 MAINTENANCE 7 3 Line voltage conversion The primary winding of the power transformer is tapped to permit The following instructions are executed by qualified personnel only To operation from 100 120V or 230V AC 50 60Hz line voltage avoid electrical shock do not perform any servicing other than the Conversion from one line voltage to another is done by changing the operating instructions unless you are qualified to do so 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 7 1 Line fuse replacement to a different line voltage perform the following procedure If the fuse blows the DMM would not work Try to determine and 1 Make sure the power cord is unplugged correct the cause of the blown fuse then replace the fuse with correct 2 Adjust the line voltage selector switch to the desired line voltage rating and type shown as below position FUSE RATING AND TYPE 3 A change in line voltage may also require a corresponding change 100 170V
8. ange Press AUTO MAN button to change manual or auto ranging 3 Connect 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 lor W to the desired range Press AUTO MAN button to change manual or auto ranging 3 Connect the test lead to the 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 ec 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 mo
9. aveform is equivalent to dc value that causes the same amount of heat to be dissipated in a nes m RR pe Since average responding meters have been in use for so long you may have accumulated test or reference data based on them Figure 1 6 1 illustrates the relationship between ac and dc components for I rV 1 919 waveforms and compares readings for true rms meters and SE Tan average responding meters Figure 6 1 will help you convert between nre T the two measurement methods Tn Mm ama X DAL HE TEE SELLR a PS RT iBEATER Tu Gene Let dig ge M pe n HU L DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL Figure 6 1 Voltage Conversion PEAK VOLTAGES METERED VOLTAGE DC AND AC AC COUPLED AC COMPONENT ONLY TOTAL RMS INPUT Ee Ra EU EIU E Ear eee WAVEFORM PK PK COMPONENT TRUE RMS CAL TRUE RMS ONLY Jac dc H SINE 2 82E 1 000 0 000 1 000 RECTIFIED SINE FULL WAVE 1 414 1 414 0 421 PK 0 435 4 3 000 RECTIFIED SINE HALF WAVE 2 000 0 771 2 000 0 636 1 110 1 000 1 000 0 000 RECTIFIED SOUARE 1 414 0 785 x 0 207
10. bols which may appear in this manual or on Equipment to prevent ANTRODUGTIION 5 damage to the instrument 39 SPECIFICATION 6 4 254 WARNING Warning statements identify condition or 5 MEASUREMENT TUTORIAL ees voe eoa eere p non nona pna 14 practices that could result in injury or loss of life 6 5 18 Jo MAINTENANCE 26400 0 ea vana odd a sodes idus 22 CAUTION Caution statements identify conditions or practices that could result in damage to this product or other property DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL DANGER High Voltage ATTENTION refer to Manual Protective Conductor Terminal gt 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 wh
11. de the maximum value 15 converted to dBm To release the dBm function press dBm again The dBm mode and AC Hz mode are not selected concurrently The standard reference impedance of the instrument is 6000 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
12. ich is coloured Green amp Yellow must be connected to the Earth terminal marked with the letter E or by the earth symbol QD or coloured Green or Green amp Yellow DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL The wire which is coloured Blue must be connected to the 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 Hed 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 cable of 0 75 2 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 wirng 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 yo
13. or peak ac ACV AC DC 5V 1000V 1000V rms continuous amp 10 VeHz maximum DCA ACA AC DC 500p A 2A fuse protected 2A 250V DC AC20A AC DC 20A DC ACmV AC DC OHM WARNING To avoid shock hazard and or instrument damage N do not apply input potentials that exceed the input overload limits shown in table 4 1 4 7 Input connections to common WARNING To avoid shock hazard and or instrument damage do not connect the common input terminal to any source of more than 500 volts DC or peak AC above earth ground 13 DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL 5 MEASUREMENT TUTORIAL 5 1 Voltage measurements DCmV ACmV Press the button to select desired function 2 Press A lor V 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 1001 V is measured Allow up to one minute prior to making low level measurements 5 2 Current measurements DCA DC 20A ACA AC 20A Press the button to select 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 r
14. sounds if conductance is less than 5 ohm Open Voltage 3 volts maximum 450V dc or peak ac continuous 11 ENVIRONMENTAL Indoor use altitude up to 2000m Ambient Temperature 0 to 50 Relative Humidity 80 Maximum Installation category II Pollution Degree 2 Storage temperature 40 C to 70 Up to 90 0 C to 35 C Up to 50 35 to 50 C except Operation Environment Relative Humidity the ranges of 2MO and 20MQ which up to 80 0 C to 35 12 GENERAL Maximum Common 500 dc or peak ac low terminal potential with Mode Voltage respect to power line ground Warm Up 0 5 hours to achieve rated accuracy 100V 120V 230V 2H 5 50 60Hz 8 6 0W Test Lead x1 Instruction manual x 1 251 W x91 H x291 D m m Approx 2 6 kg WARNING To avoid electrical shock the power cord protective grounding conductor must be connected to ground CAUTION To avoid damaging the instrument do not use it in a place where ambient temperature exceeds 50 gt p 10 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 AC power line connector and fuse amp line voltage selector and input fuse holder 4 2 The SHIFT key and f
15. u to display two functions of the input signal being measured Features 50000 counts DMM Multi function ACV ACA DCA 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 accuracy 20A high current range 1200V 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 90 Accuracy is expressed as percentage of reading digits The AC specification is based on the 50 of duty cycle DC VOLTAGE RANGE RESOLUTION ACCURACY INPUT IMPEDANCE 500mV 10u V 1OMQ 100p V 11 1 MQ T 10 1MQ 500V 10 1200V 100mV 0 03 9 10 nput Impedance Approx 10MQ in parallel with 100pF all ranges gt 60dB at 60Hz or 50Hz Normal Mode Rejection Ratio Common Mode Rejection Ratio 90dB at 60Hz or 50Hz Common Mode Voltage Max 500V dc or peak ac Maximum Input 450V dc or peak ac continuous on 500mV range 1200V dc or peak ac continuous on other range Bm ref 6000 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 TRUE RMS AC OR AC DC
16. unction 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 indication An input is over range if it exceeds the full scale of the selected range GDM 8245 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 99 exceeds 51kHz the primary display will show DUAL DISPLAY DIGITAL MULTIMETER USER MANUAL Figure 4 1 Front Panel Secondary Display Primary Display Input Terminals EL oem nas DAAL ee TRENT AEEA BESTE Push Buttons Figure 4 2 Rear Panel Line Voltage Sefector and Input Fuse Holder AC PowerLine 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 MAXIMUN INPUT DCV 5V 1200V 1200Vdc
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