Datasheet DPM3AS-BL Datasheet (LASCAR)

DPM 3AS-BL

3½ Digit Backlit LCD Voltmeter Module

PRODUCT DESCRIPTION

The DPM 3AS-BL features a 200mV d.c. measurement range with auto-zero andauto-polarity. Decimal points are user
selectable.
to its own power supply GND. The design
of the panel meter's housing allows the module to be low cost means it will

The DPM 3AS-BL features a negative rail generator whichenables the meter to measure a signalreferenced

LED backlighting ensures excellent readability under low light conditions.

easily snapped into a panel. The module's
suit high and low volume applications. The DPM 3AS-BL is intended to replace the DPM 3, DPM 3S, DPM 3-BL and
DPM 3S-BL in many applications, usually requiring only minor circuit modifications.

FEATURES

mm (0.43") Digit Height

•11

• 200mV d.c. Full Scale Reading

• 3.0 to 7.5V or 6.0 to 15.0V Operation

•

Auto-zero and Auto-polarity

•

Programmable Decimal Points

•

LED Backlighting

TYPICAL APPLICATIONS

• Precision Instrumentation Systems

• Power Supply Monitoring

• Hand held instruments

• Panel-Mount Indication

• Low Power Voltage Measurement

ORDERING INFORMATION

Stock Number

Standard Meter DPM 3AS-BL

ELECTRICAL SPECIFICATIONS

Specification Min. Typ. Max. Unit

Accuracy (overall error) * 0.1 % (±1 count)
Linearity ±1 count
Sample rate 2.5 samples/sec
Operating temperature range 0 50 °C
Temperature stability 250 ppm/°C
Meter supply voltage V+ to GND configuration 3.0 5.0 7.5 V d.c.

Meter supply current V+ to GND configuration 350 A

Backlight supply voltage 4.75 5.0 *** V d.c.
Backlight supply current @ 5V d.c. 40 60 mA
Input 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.

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.

V+ to V- configuration 6.0 9.0 15.0** V d.c.

µ

V+ to V- configuration

A supply clock

175 A

µ

SAFETY

To comply with the Low Voltage Directive (LVD 93/68/EEC), input voltages to the module’s pins must not exceed
60Vdc. The user must ensure thatthe incorporationof thepanel meter into the user ’s equipment conforms to the
relevant sections of BS EN 61010 (Safety Requirements for Electrical Equipment for Measuring, Control and
Laboratory Use).

LASCAR ELECTRONICS LTD.
MODULE HOUSE
WHITEPARISH
WILTSHIRE SP5 2SJ
UK
TEL: [phone]
FAX: [phone]
E-mail: [email protected]

LASCAR ELECTRONICS INC.
3750 WEST 26th STREET
ERIE
PA 16506
USA
TEL: [phone]
FAX: [phone]
E-mail: [email protected]

www.lascarelectronics.com

LASCAR ELECTRONICS (HK) LIMITED
FLAT C, 5/FL., LUCKY FTY. BLDG.
63-65 HUNG TO ROAD
KWUN TONG KOWLOON
HONG KONG
TEL: [phone]
FAX: [phone]
E-mail: [email protected]

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DPM 3AS-BL

DIMENSIONS

All dimensions in mm (inches)

Panel cut-out: 38.0 x 18.0

PANEL FITTING

(1.50 x 0.71)

20.0 (0.79)

17.5 (0.69)

Panel thickness: 1.0 - 2.5

(0.04 - 0.10)

3½ Digit Backlit LCD Voltmeter Module

2.54 (0.1)

0.50 (0.02)
pin width

37.5 (1.48)

40.0 (1.57)

pin pitch

6.00 (0.24)

ab d

2.00 (0.08)

13.5 (0.53)

c

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

Panel

Module

1

FUNCTIONAL BLOCK DIAGRAM

L-L+

8

1

COM

REF HI

REF LO

INHI

INLO

Vref

V+

CAL

+

_

A/D

2

COM

IN HI

(rear view)

1

V-

IN LO

PIN CONFIGURATION

11

LREF

BAT

XDP

TEST

CAL

L-

L+

12 13

V+

GND

REF HI

REF LO

DP1DP2 DP3 BAT

V-TEST

BAT XDPGND

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DPM 3AS-BL

CIRCUIT DIAGRAM

8

V+

R10
100k

INHI

INLO

COM

REF HI

REF LO

GND

LREF

R9
3k

3

2

4

R3

1.5k

6

5

7

1

V-

13

L+

12

L-

R11

22R

C1

47nF

C2

220nF

C4

100nF

R4

C5C7C6

180k

47pF1u51u5

180k

3½ Digit Backlit LCD Voltmeter Module

1

5

V+

27

INT

28

BUF

29

R1

A/Z

31

IN HI

30

IN LO

32

COM

34

CREF+

33

CREF-

36

REF HI

35

REF LO

38

OSC3

39

OSC2

40

OSC1

LED1LED2

IC1

V-

a1

4

b1

3

c1

2

d1

8

e1

6

f1

7

g1

12

a2

11

b2

10

c2

9

d2

14

e2

13

f2

25

g2

23

a3

16

b3

24

c3

15

d3

18

e3

17

f3

22

g3

19

ab

20

POL

21

BP

TEST

37

26

R2
1M

Q1
BCX19

V+

a1
b1
c1
d1
e1
f1
g1
a2
b2
c2
d2
e2
f2
g2
a3
b3
c3
d3
e3
f3
g3
ab
POL
COM

LCD1

R5
100k

DP1

DP2

DP3

LOBAT

BAT

199.9

19.99

1.999

DP1

DP2

DP3

R71MR6

R8
1M

1M

11

BAT

10

XDP

9

TEST

PIN FUNCTIONS

1. V- Negative power supplyto themeter (6.0to 15.0Vmeter power supply applicationsonly).

2. INLO Negativemeasuring input.

3. INHI Positivemeasuring input.

4. COM Ground forthe analogue section ofthe A/D converter.It is activelyheld at3.05V (nom.)below V+ and mustnot be

5. REF LO Negative input forreference voltage.

allowed to sinkexcessive current (>100 A) by,for instance,connecting to ahigher voltage.

6. REF HI Positiveinput for reference voltage.

7. GND 0V power supplyto themeter (3.0 to7.5V meterpower supply applications only).

8. V+ Positivepower supplyto themeter.

9. TEST Connect to V+to testtheLCD. Do notconnectto V+ formore thana few secondsas thismay damagethe LCD.
TEST is heldactively at5V (nom.)below V+and is theground forthe digitalsection ofthe meter.It canbe used to
power external logicup toa maximumof1mA.

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.

Note:
A negative supply is generatedinternally andmirrors thepositive supply. For example: ifV+ is+5V, then theinternally generatedV-

is -5V. When measuring with the input referenced to the same supply rail as that of the panel meter, thenthe limitationson theinput
range are (V- +1.5V) to(V+ -1.5V).

Solder Links:
LREF Normally Closed. Enables theinternal voltagereference circuit. Cut thislink when using anexternal voltage reference.
BAT Normally Open. Disables the LowBattery warningannunciator. Cutthis link and adda low battery detection circuit

to enable theLow Batterywarning annunciator viaPin 11(BAT).
DP1 Normally Open. Close thissolder linkto enabledecimal pointDP1.
DP2 Normally Open. Close thissolder linkto enabledecimal pointDP2.
DP3 Normally Open. Close thissolder linkto enabledecimal pointDP3.

µ

V+

1M

1M

SET
THRESHOLD

BC 237

470k

Check Link BAT is OPEN.

4077

8

V+

10

XDP

11

BAT

9

TEST

V-

1

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DPM 3AS-BL

3½ Digit Backlit LCD Voltmeter Module

SCALING

Two external resistors Ra
and Rb may be used to
alter the full scale reading
(FSR) of the meter - see
table. The meter will have
to be re-calibrated by
adjusting the calibration
potentiometer on the rear
of themodule.

Voltage

(Vin) 200V 1M 1k

Current

I

( in) 20mA 0R 10R

*Ensure that Ra is rated for high voltage use.

FSR Ra Rb

2V 910k 100k

20V 1M 10k

2000V* 1M 100R

200 A 0R 1k

µ

2mA 0R 100R

200mA 0R 1R

+

Vin or inI

-

Ra 1M

Rb

Input Filter

10nF

INHI

DPM 3AS-BL

INLO

APPLICATIONS

Do not connect more than one meter to the same power supply if the meters cannot use the same signal
ground. Takingany input beyond thepower supplyrails will damage themeter.

5V supply operation (3.0 to 7.5V Meter PowerSupply)

+3.0 to +7.5V

+

±200mV

-

1M

10nF

3

2
4
5

8

V+

INHI

INLO
COM
REF LO

GND

7

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

0V

+3.0 to +7.5V

+

±200mV

-

1M

10nF

3

2
4
5

8

V+

INHI

INLO
COM
REF LO

GND

7

Measuring an input voltage referenced to
a floating supply, i.e. the input voltage
and the meter's power supply are isolated
from each other.
Ensure solder link LREF is closed.

9V supply operation (6.0 to 15.0V Meter PowerSupply)

+3.0 to +7.5V

+

±200mV

-

-3.0 to -7.5V

1M

10nF

3

2
4
5

8

V+

INHI

INLO
COM
REF LO

V-

1

+6.0 to +15.0V

+

±200mV

-

1M

10nF

3

2
4
5

8

V+

INHI

INLO
COM
REF LO

V-

1

L+

L+

+3.0 to +7.5V

if V+>5V then
Rs=(V+ - 5V)

13

12

L-

0.04

I+

1M

Rb

10nF

I-

0V

3

2
4
5

INHI

INLO
COM
REF LO

V+

GND

8

7

0V

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

+6.0 to +15.0V

Rs=(V+ - 5V)

13

12

L-

0.04

I+

1M

Rb

10nF

I-

0V

3

2
4
5

INHI

INLO
COM
REF LO

V+

V-

8

1

0V

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

Measuring an input voltage referenced to
a floating supply, i.e. the input voltage
and the meter's power supply are isolated
from each other.
Ensure solder link LREF is closed.

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

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

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