dpm 3as-bl 3‰ digit backlit lcd voltmeter module · dpm 3as-bl 3‰ digit backlit lcd voltmeter...

PRODUCT DESCRIPTIONThe DPM 3AS-BL features a 200mV d.c. measurement range with auto-zero and auto-polarity. Decimal points are userselectable.

LED backlighting ensures excellent readability under low light conditions.easily snapped into a panel. The module's

The DPM 3AS-BL features a negative rail generator which enables the meter to measure a signal referencedto its own power supply GND. The designof the panel meter's housing allows the module to be low cost means it willsuit high and low volume applications. The DPM 3AS-BL is intended to replace the DPM 3, DPM 3S, DPM 3-BL andDPM 3S-BL in many applications, usually requiring only minor circuit modifications.

FEATURES• 11• 200mV d.c. Full Scale Reading• 3.0 to 7.5V or 6.0 to 15.0V Operation•••

mm (0.43") Digit Height

Programmable Decimal PointsLED Backlighting

Auto-zero and Auto-polarity

TYPICAL APPLICATIONS• Precision Instrumentation Systems• Power Supply Monitoring• Hand held instruments• Panel-Mount Indication• Low Power Voltage Measurement

ORDERING INFORMATIONStock Number

Standard Meter DPM 3AS-BL

DPM 3AS-BL 3½ Digit Backlit LCD Voltmeter Module

SAFETYTo comply with the Low Voltage Directive (LVD 93/68/EEC), input voltages to the module’s pins must not exceed60Vdc. The user must ensure that the incorporation of the panel meter into the user’s equipment conforms to therelevant sections of BS EN 61010 (Safety Requirements for Electrical Equipment for Measuring, Control andLaboratory Use).

Page 2 of 4Page 2 of 4

of 4www.lascarelectronics.com

LASCAR ELECTRONICS LTD.MODULE HOUSEWHITEPARISHWILTSHIRE SP5 2SJUKTEL: +44 (1794) 884567FAX: +44 (1794) 884616E-mail: [email protected]

LASCAR ELECTRONICS (HK) LIMITEDFLAT C, 5/FL., LUCKY FTY. BLDG.63-65 HUNG TO ROADKWUN TONG KOWLOONHONG KONGTEL: +852 2797 3219FAX: +852 2343 6187E-mail: [email protected]

ELECTRICAL SPECIFICATIONSSpecification Min. Typ. Max. UnitAccuracy (overall error) * 0.1 % (±1 count)Linearity ±1 countSample rate 2.5 samples/secOperating temperature range 0 50 °CTemperature stability 250 ppm/°CMeter supply voltage V+ to GND configuration 3.0 5.0 7.5 V d.c.

175 ABacklight supply voltage 4.75 5.0 *** V d.c.Backlight supply current @ 5V d.c. 40 60 mAInput leakage current (Vin = 0V) 1 10 pA

* To ensure maximum accuracy, re-calibrate periodically.** Operation of the meter beyond the maximum supply voltage rating may cause permanent damage to the meter.*** An external series resistor is required above 5V, see Applications.

V+ to V- configuration 6.0 9.0 15.0** V d.c.Meter supply current V+ to GND configuration 350 A

V+ to V- configurationµµ

Unless otherwise noted, specifications apply at T =25°C, V =5Vd.c. (f =48kHz) and are tested with the module configured for fully floating

input mode.A supply clock

LASCAR ELECTRONICS INC.3750 WEST 26th STREETERIEPA 16506USATEL: +1 (814) 835 0621FAX: +1 (814) 838 8141E-mail: [email protected]

40.0 (1.57)

37.5 (1.48)

17

.5(0

.69

)

20

.0(0

.79

)

a. 2.00 (0.08)b. 6.00 (0.24)c. 1.60 (0.06)d. 6.00 (0.24)

0.50 (0.02)pin width 6.00 (0.24)

13

.5(0

.53

)

2.0

0(0

.08

)

2.54 (0.1)pin pitch

a b d

c

Panel thickness: 1.0 - 2.5(0.04 - 0.10)

Panel cut-out: 38.0 x 18.0(1.50 x 0.71)

DIMENSIONSAll dimensions in mm (inches)


PANEL FITTING

PIN CONFIGURATION (rear view)FUNCTIONAL BLOCK DIAGRAM

Vref

Module

1

Panel

2

of 4Page 2 of 4

Page 2 of 4

1 8

A/D+_

INHI

REF HI

COM

INLO

REF LO

BAT XDPGND

V+

V-TEST

L-L+

CAL

www.lascarelectronics.com

CALLREF

DP1DP2 DP3 BAT

11

12 13

1

BA

T

XD

PL-

TES

TL+

V+

GN

D

REF

HI

REF

LO

CO

M

INH

I

INLO V

-


of 4

CIRCUIT DIAGRAM


PIN FUNCTIONS1. V- Negative power supply to the meter (6.0 to 15.0V meter power supply applications only).2. INLO Negative measuring input.3. INHI Positive measuring input.4. COM Ground for the analogue section of the A/D converter. It is actively held at 3.05V (nom.) below V+ and must not be

allowed to sink excessive current (>100 A) by, for instance, connecting to a higher voltage.5. REF LO Negative input for reference voltage.6. REF HI Positive input for reference voltage.7. GND 0V power supply to the meter (3.0 to 7.5V meter power supply applications only).8. V+ Positive power supply to the meter.9. TEST Connect to V+ to test the LCD. Do not connect to V+ for more than a few seconds as this may damage the LCD.

TEST is held actively at 5V (nom.) below V+ and is the ground for the digital section of the meter. It can be used topower external logic up to a maximum of 1mA.

10. XDP Inversion of LCD drive voltage.11. BAT Low Battery annunciator drive pin. See application on the right.

This pin is not fitted as standard.12. L- Negative power supply to LED backlighting.13. L+ Positive power supply to LED backlighting.

The backlighting is internally configured for 5V operation.If a higher voltage is used, then add a series current limiting resistor Rs.See Applications for calculations of Rs.

A negative supply is generated internally and mirrors the positive supply. For example: if V+ is +5V, then the internally generated V-is -5V. When measuring with the input referenced to the same supply rail as that of the panel meter, then the limitations on the inputrange are (V- + 1.5V) to (V+ - 1.5V).

LREF Normally Closed. Enables the internal voltage reference circuit. Cut this link when using an external voltage reference.BAT Normally Open. Disables the Low Battery warning annunciator. Cut this link and add a low battery detection circuit

to enable the Low Battery warning annunciator via Pin 11 (BAT).DP1 Normally Open. Close this solder link to enable decimal point DP1.DP2 Normally Open. Close this solder link to enable decimal point DP2.DP3 Normally Open. Close this solder link to enable decimal point DP3.

µ

Note:

Solder Links:

V+8

3

2

4

6

5

7

1

13

12

INHI

INLO

COM

REF HI

REF LO

GND

V-

L+

L-

INTV+

V- TEST

a1 a127

1

26

28

29

31

30

32

34

36

35

33

d1 d1e1 e1f1 f1

DP1199.9

DP219.99

DP31.999

g1 g1

f2 f2

a2 a2

g2 g2

e3 e3

b2 b2

a3 a3

f3 f3

c2 c2

b3 b3

g3 g3

d2 d2

c3 c3

ab ab

e2 e2

d3 d3

b1 b1c1 c1

5

2867

13

12

25

18

11

23

17

10

16

22

9

24

19

14

15

43

BUF

A/Z

IN HI

IN LO

COM

CREF+

CREF-

REF HI

REF LO

IC1 LCD1

R4

R11

LED1LED2

180k

22R

47pF1u51u5C5C7C6

C4100nF

C147nF

R1180k

C2220nF

LREF

DP1

DP2

DP3

BAT

R10100k

R93k

R31.5k

37

POL POLBP COM

2021

40

39

38OSC3

OSC2

OSC1

10

11

9

V+

XDP

BAT

TEST

LOBAT

R81M

R5100k

R21M

Q1BCX19

R71M

R61M

Check Link BAT is OPEN.

V+

V+XDP

BAT

TEST

8

10

1V-

1M

470k

1M

4077

11

9

SETTHRESHOLD

BC 237


Specifications liable to change without prior warning DPM 3AS-BL Issue 4 December/2002 M.C. Applies to DPM 3AS-BL/5

APPLICATIONSDo not connect more than one meter to the same power supply if the meters cannot use the same signalground. Taking any input beyond the power supply rails will damage the meter.

of 4Page 4 of 4

SCALINGTwo external resistors Raand Rb may be used toalter the full scale reading(FSR) of the meter - seetable. The meter will haveto be re-calibrated byadjusting the calibrationpotentiometer on the rearof the module.

FSR Ra Rb2V 910k 100k

20V 1M 10k(Vin) 200V 1M 1k

2000V* 1M 100R200 A 0R 1k2mA 0R 100R

( in) 20mA 0R 10R200mA 0R 1R

µ

I

Voltage

Current

Page 4 of 4

*Ensure that Ra is rated for high voltage use.

5V supply operation (3.0 to 7.5V Meter Power Supply)

9V supply operation (6.0 to 15.0V Meter Power Supply)

Measuring a single ended inputvoltage referenced to supply, i.e. theinput voltage and the meter's powersupply share the same 0V rail.Ensure solder link LREF is closed.

Measuring a single ended inputvoltage referenced to supply, i.e. theinput voltage and the meter's powersupply share the same 0V rail.Ensure solder link LREF is closed.

Measuring a current from a circuit which isfloating with respect to the DPM's supply,i.e. the current and the meter's powersupply are isolated from each other.Ensure solder link LREF is closed.

Measuring a current from a circuit which isfloating with respect to the DPM's supply,i.e. the current and the meter's powersupply are isolated from each other.Ensure solder link LREF is closed.

Measuring an input voltage referenced toa floating supply, i.e. the input voltageand the meter's power supply are isolatedfrom each other.Ensure solder link LREF is closed.

Measuring an input voltage referenced toa floating supply, i.e. the input voltageand the meter's power supply are isolatedfrom each other.Ensure solder link LREF is closed.


+3.0 to +7.5V

7

8

12

133

2

4

5

V+

INHI

INLO

COMREF LO

GND

+

-

±200mV

0V

L-

L+

if V+>5V thenRs=(V+ - 5V)

0.041M

10nF

+6.0 to +15.0V

1

8

12

133

2

4

5

V+

INHI

INLO

COMREF LO

V-

+

-

±200mV

0V

L-

L+

Rs=(V+ - 5V)0.041M

10nF

+3.0 to +7.5V

+6.0 to +15.0V

7

1

8

8

3

3

2

2

V+

V+

INHI

INHI

4

4

5

5

COM

COM

REF LO

REF LO

INLO

INLO

0V

0V

GND

V-

Rb

Rb

I+

I+

I-

I-

1M

1M

10nF

10nF

+3.0 to +7.5V

7

8

3

2

4

5

V+

INHI

INLO

COMREF LO

GND

+

-

±200mV

0V

1M

10nF

+3.0 to +7.5V

-3.0 to -7.5V1

8

3

2

4

5

V+

INHI

INLO

COMREF LO

V-

+

-

±200mV

1M

10nF

+

-

Ra 1M

Rb

INHI

Vin or inI

INLO

DPM 3AS-BL10nF

Input Filter

dpm 3as-bl 3‰ digit backlit lcd voltmeter module · dpm 3as-bl 3‰ digit backlit lcd voltmeter...

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