LG DM-311 Reference guide

Adjustment and Test procedure Manual
for digital multimeter
Model : DM-311
LG Precision Co., Ltd.
1999/8/12

Adjustment and test procedure Manual DM-311
Version 1.0 Page 2of 12 99-08-26
LG Precision Co., Ltd.
Revision History
NO Modification ECN NO Date Name

Adjustment and test procedure Manual DM-311
Version 1.0 Page 3of 12 99-08-26
LG Precision Co., Ltd.
nGeneral Specifications of DM-311
Display : 3½ Digit Multimeter
Battery Life : Typical 200 hours
Operating Temperature : 0ºC ~ 40ºC (Below 80% RH)
Storage Temperature : -10ºC ~ 60ºC (Below 70% RH)
Accuracy guaranteed temperature : 23ºC ±5ºC (Below 80% RH)
nExplanation of each part of DM-311
¨ç Terminal 10A
Used for measuring DC/AC current below 10A current.
¨è Terminal COM
Used for commom terminal.
¨é Terminal Ω-V
Used for AC/DC voltage or resistance measure terminal.
¨ê Terminal mA
Used for measuring DC/AC current below 200mA current
¨ë LCD display
¨ì Rotary S/W
Used for selecting mode and range
Fig 1 - Front View of DM-311
Note
Adjustment and Test of DM-311 should be conducted under proper test environment
Check temperature and relative humidity before adjustment and test.
Accuracy guaranteed temperature : 23ºC ±5ºC (Below 80% RH)
5

Adjustment and test procedure Manual DM-311
Version 1.0 Page 4of 12 99-08-26
LG Precision Co., Ltd.
nTest Equipment List
DMM Calibrator : 1 set
Decade Resistor : 1 set
DC Power Supply or 9V Battery
nCalibration Procedure
1. Power On Test
Set DM-311 to anymode byusing Rotary S/W.
Check LCD display is turned on.
2. LCD Display Test
Check LCD Display to each range byselecting range with Rotary S/W. Below chart shows correct display
Function LCD Display to each range
DC VOLTAGE 00.0 →.000 →0.00 →00.0 →000
AC VOLTAGE 00.0 →.000 →0.00 →00.0 →000
DC CURRENT 00.0 →.000 →0.00 →00.0 →0.00
AC CURRENT00.0 →.000 →0.00 →00.0 →0.00
RESISTANCE 1 . →1. →1. →1 . →1. →1.
BAT.000 →0.00
DIODE &
CONTINUITY 1
3. Low Battery Warning Display Test
Check a message, “BATT” on LCD display when Power supply or BatteryVoltage goes under 6.4V.

Adjustment and test procedure Manual DM-311
Version 1.0 Page 5of 12 99-08-26
LG Precision Co., Ltd.
4. Adjustment of DC voltage, AC voltage and DC current.
Item Specification Procedure
DC
Voltage 189.8mV ~ 190.2mV
1. Set RotaryS/W to DC Voltage Mode
2. Apply DC 190mV to Terminal COM and Terminal V of DM-311 with
a calibrator
3. Adjust VR1 to be displayed 190.0mV on LCD display
AC
Voltage 189.5mV ~ 190.5mV
1. Set RotaryS/W to AC Voltage Mode
2. Apply AC 190mV/60Hz to Terminal COM and Terminal V of DM-311 with
a calibrator
3. Adjust VR2 to be displayed 190.0mV on LCD display
DC
Current 9.95A ~ 10.05 A
1. Set RotaryS/W to DC Current 10A Mode
2. Apply DC 10A current to terminal COM and terminal 10A of DM-311
with a calibrator
3. Adjust Mn Wire(R39) with ripper to be displayed 10.00A on LCD display.
5.Test 5-1 No Input on DC Voltage Mode
nSpecification : ±00.1
nSet RotaryS/W to DC Voltage mode and check DM-311to meet the above specification.
5-2 Short-circuit on DC Voltage Mode
nSpecification : ±00.1
nSet RotaryS/W to DC Voltage mode and Short-circuit between COM terminal and V terminal
nCheck DM-311 to meet the above specification.
5-3 DC Voltage Measurement Test
Set Rotary S/W to DC Voltage Mode and Apply below voltage to terminal COM and terminal V to each
range with a calibrator
Range Customer
Specification Factory Specification Test DC Voltage
DC 200mV 190mV
DC 2V 1.9V
DC 20V 19V
DC 200V 190V
DC 1000V
±(0.5% + 1dgt) ±(0.4% + 1dgt)
1000V

Adjustment and test procedure Manual DM-311
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LG Precision Co., Ltd.
5-4 AC Voltage Measurement Test
Set Rotary S/W to AC Voltage Mode and Apply below voltage to terminal COM and terminal V to each
range with a calibrator. Check the measurement value to each frequency, 60Hz and 400Hz.
Range Customer
Specification Factory Specification Test AC Voltage
AC 200mV 190mV/60Hz
190mV/400Hz
AC 2V 1.9V/60Hz
1.9V/400Hz
AC 20V 19V/60Hz
19V/400Hz
AC 200V 190V/60Hz
190V/400Hz
AC 750V
±(0.75%+3dgt) ±(0.65%+3dgt)
750V/60Hz
750V/400Hz
5-5 DC Current Measurement Test
Set Rotary S/W to DC Current Mode and Apply below DC current to terminal COM and terminal mA to
each range with a calibrator. Check the measurement value to each range
Range Customer
Specification Factory Specification Test DC Current
DC 200µΑ 190µΑ
DC 2mΑ1.9mΑ
DC 20mΑ19mΑ
DC 200mΑ
±(1.0%+2dgt) ±(0.9%+2dgt)
190mΑ
Apply below DC current to to terminal COM and terminal 10A with a calibrator.
Range Customer
Specification Factory Specification Test DC Current
DC 10A ±(1.5%+2dgt) ±(1.4%+2dgt) 9A

Adjustment and test procedure Manual DM-311
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LG Precision Co., Ltd.
5-6 AC Current Measurement Test
Set Rotary S/W to AC Current 20mA Mode and Applybelow AC current to terminal COM and terminal
mA to each range with a calibrator. Check the measurement value to each range
Range Customer
Specification Factory Specification Test AC Current
AC 200µΑ 190µΑ/60Hz
190µΑ/400Hz
AC 2mΑ1.9mΑ/60Hz
1.9mΑ/400Hz
AC 20mΑ19mΑ/60Hz
19mΑ/400Hz
AC 200mΑ
±(2.0%+2dgt) ±(1.9%+2dgt)
190mΑ/60Hz
190mΑ/400Hz
Apply below AC current to terminal COM and terminal 10A with a calibrator.
Range Customer
Specification Factory Specification Test AC Current
AC 10A ±(3.0%+2dgt) ±(2.9%+2dgt) 9A/60Hz
9A/400Hz
5-7 Resistance Measurement Test
Set Rotary S/W to Resistance Measure Mode and Applybelow resistance value to terminal COM and
terminal V to each range with decade resistor. Check the measurement value to each range
Range Customer
Specification Factory Specification Test Resistance value
200Ω ±(0.5%+4dgt) ±(0.4%+4dgt) 190Ω
2kΩ1.9kΩ
20kΩ19kΩ
200kΩ190kΩ
2MΩ
±(0.5%+1dgt) ±(0.4%+1dgt)
1.9MΩ
20MΩ ±(1.0%+1dgt) ±(0.9%+1dgt) 10MΩ

Adjustment and test procedure Manual DM-311
Version 1.0 Page 8of 12 99-08-26
LG Precision Co., Ltd.
5-8 Diode & Continuity Test
Set Rotary S/W to diode & continuity test mode and apply a diode to terminal COM and terminal V with
forward direction.
Range Customer
Specification Factory Specification
Diode Forward Direction : less than 450
Reverse Direction : more than 1
Set RotaryS/W to diode & continuity test mode and Short-circuit between terminal COM and terminal V.
Buzzer will sound when measurement is less than 200 Ω
Range Customer
Specification Factory Specification
ContinuityOpen Circuit : 1
Short Circuit : less than 00.4
5-9 Battery Test
Set Rotary S/W to BAT 1.5V Range and apply below current to terminal COM and terminal V with a
calibrator
Range Customer
Specification Factory Specification Test DC Current
1.5V 1.0 ~ 2.0 1.5mA
9V 6.0 ~ 9.0 7.5mA
5-10 Short-circuit ohm Test
Set RotaryS/W to Resistance measure mode and short-circuit between terminal COM and terminal V
Range Customer
Specification Factory Specification
200ΩLess than 0.4Ω

Adjustment and test procedure Manual DM-311
Version 1.0 Page 9of 12 99-08-26
LG Precision Co., Ltd.
Appendix A ) Bill of material
LGP P/N CategorySpecification PCB F/N Quantity
334-013-1 BUSHING INPUT CORE BLACK DMM 1
334-013-2 BUSHING INPUT CORE RED DMM 3
362-035 SPRING SHIELD SPRING DMM SP1 1
384-017-1 HOLDERBAT SNAP 9V UL 1
418-100 FILM VINYL PPI255 W=65.0 DMM M 1
513-556R3 PCB BARE B/D DM-311 PCB REV 3 1
563-063-2 FUSE 250V 0.25A 50F UL&EU F1 1
563-065 FUSE 250V 10A H216010 ULE14080 F2 1
563-068 FUSE 125V 1A 22NM MICRO 101L F3 1
564-015 FUSE HOLDER FUSE HOLDER FC51A(DMM) 4
571-317 VARIABLE RESISTOR VR TMC3K 200 (SMD)VR01 1
571-320 VARIABLE RESISTOR VR TMC3K 2K (SMD) VR02 1
573-126 RESISTOR W.W 0.99 OHM 1W 0.5% R38 1
573-142 RESISTOR M.F 100 -OHM 1/4W -0.2/0.05%R26 1
573-143 RESISTOR M.G 9 MOHM 1/2W -0.2/0.05% R21 1
573-144 RESISTOR M.F 900 KOHM 1/4W -0.2/0.05% R22 1
573-145 RESISTOR M.F 90 KOHM 1/4W -0.2/0.05%R23 1
573-146 RESISTOR M.F 9 KOHM 1/4W -0.2/0.05%R24 1
573-147 RESISTOR M.F 900 OHM 1/4W -0.2/0.05% R25 1
574-052-2 PTC PT05MP-L1K6001 R27 1
574-052-2 PTC PT05MP-L1K6001 R28 1
574-052-2 PTC PT05MP-L1K6001 R27A 1
574-055 SPARK GAP AG15PC 152FS-K2M DAIYOYDEN SG1 1
581-160 CAPACITOR ELEC 47UF 16V SRE-TYP C08 1
581-160 CAPACITOR ELEC 47UF 16V SRE-TYP C09 1
581-162 CAPACITOR ELEC 1UF 50V SRE-TYPE C11 1
581-162 CAPACITOR ELEC 1UF 50V SRE-TYPE C13 1
581-162 CAPACITOR ELEC 1UF 50V SRE-TYPE C14 1
581-162 CAPACITOR ELEC 1UF 50V SRE-TYPE C15 1
581-176 CAPACITOR ELEC 10UF 16V SRE-TYPE C06 1
581-194 CAPACITOR MP 0.22UF 63V K MMY168 C02 1
581-194 CAPACITOR MP 0.22UF 63V K MMY168 C03 1
581-195 CAPACITOR MP 0.1UF 63V J MMY168C04 1
581-195 CAPACITOR MP 0.1UF 63V J MMY168C05 1
581-195 CAPACITOR MP 0.1UF 63V J MMY168C12 1
585-154-1 DIODE RL105 D01 1
585-154-1 DIODE RL105 D02 1
585-154-1 DIODE RL105 D4,D5 2
585-248 DIODE KDS226 (SMD) KEC D03 1
591-647-2 IC MC74HC00AD (SMD) MOTOROLA U03 1
591-648 IC TC7106ACKW A-D CON TELEDYNE U01 1
591-650 IC NJM062M-T1 OP-AMP NJRC U04 1
591-660 IC MC14070BD U02 1

Adjustment and test procedure Manual DM-311
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LG Precision Co., Ltd.
LGP P/N CategorySpecification PCB F/N Quantity
611-665 TRANSISTOR KRC110S (SMD) Q03 1
611-670 TRANSISTOR KTC3875Y(SMD) SOT-23 Q01 1
611-670 TRANSISTOR KTC3875Y(SMD) SOT-23 Q02 1
611-671 TRANSISTOR SS8050 SAMSUNG Q04 1
611-671 TRANSISTOR SS8050 SAMSUNG Q05 1
637-013 BUZZER BUZZ SBT-11P B1 1
873-028R MN WIRE MN WIRE CM2 10MOHM R39 1
873-027 Mn WIRE CM2 DIA 1.6MM Mn WIRE CM2 DIA1.6MM 1
CK1HI101J CAPACITOR CER 100PF 50V J (2012)C01 1
CK1HI102K CAPACITOR CER 1000PF 50V K (2012) C17 1
CK1HI221J CAPACITOR CER 220PF 50V J (2012)C07 1
CK1HR104ZCAPACITOR CER 0.1UF 50V Z T.P C16 1
RD0BP105J RESISTOR C.F 1 MOHM 1/4W 5% R40 1
RD0CP102J RESISTOR C.F 1 KOHM 1/2W 5% R47 1
RG0CP226J RESISTOR M.G 22 MOHM 1/2W 5% R41 1
RMAH1000J RESISTOR M.F 100 -OHM 1/8W 5% (3216)R46 1
RMAH1001F RESISTOR M.F 1 KOHM 1/8W 1% (3216) R48 1
RMAH1002F RESISTOR M.F 10 KOHM 1/8W 1% (3216)R42 1
RMAH1002F RESISTOR M.F 10 KOHM 1/8W 1% (3216)R43 1
RMAH1003F RESISTOR M.F 100 KOHM 1/8W 1% (3216) R01 1
RMAH1003J RESISTOR M.F 100 KOHM 1/8W 5% (3216) R06 1
RMAH1003J RESISTOR M.F 100 KOHM 1/8W 5% (3216) R30 1
RMAH1004F RESISTOR M.F 1 MOHM 1/8W 1% (3216) R13 1
RMAH1004F RESISTOR M.F 1 MOHM 1/8W 1% (3216) R14 1
RMAH1004J RESISTOR M.F 1 MOHM 1/8W 5% (3216) R03 1
RMAH1004J RESISTOR M.F 1 MOHM 1/8W 5% (3216) R07 1
RMAH1004J RESISTOR M.F 1 MOHM 1/8W 5% (3216) R08 1
RMAH1004J RESISTOR M.F 1 MOHM 1/8W 5% (3216) R10 1
RMAH1004J RESISTOR M.F 1 MOHM 1/8W 5% (3216) R11 1
RMAH1004J RESISTOR M.F 1 MOHM 1/8W 5% (3216) R12 1
RMAH1004J RESISTOR M.F 1 MOHM 1/8W 5% (3216) R31 1
RMAH1004J RESISTOR M.F 1 MOHM 1/8W 5% (3216) R32 1
RMAH1004J RESISTOR M.F 1 MOHM 1/8W 5% (3216) R34 1
RMAH10R0J RESISTOR M.F 10 -OHM 1/8W 5% (3216) R50 1
RMAH1102FRESISTOR M.F 11 KOHM 1/8W 1% (3216)R17 1
RMAH1503J RESISTOR M.F 150 KOHM 1/8W 5% (3216) R09 1
RMAH1802J RESISTOR M.F 18 KOHM 1/8W 5% (3216)R05 1
RMAH2003J RESISTOR M.F 200 KOHM 1/8W 5% (3216) R49 1
RMAH2201F RESISTOR M.F 2.2 KOHM 1/8W 1% (3216) R16 1
RMAH3300F RESISTOR M.F 330 -OHM 1/8W 1% (3216)R18 1
RMAH3301J RESISTOR M.F 3.3 KOHM 1/8W 5% (3216) R45 1
RMAH4702F RESISTOR M.F 47 KOHM 1/8W 1% (3216)R02 1
RMAH4702J RESISTOR M.F 47 KOHM 1/8W 5% (3216)R04 1
RMAH4702J RESISTOR M.F 47 KOHM 1/8W 5% (3216)R15 1
RMAH4703J RESISTOR M.F 470 KOHM 1/8W 5% (3216) R44 1