Datasheet DMS-EB2, DMS-20LCD-2-5, DMS-20LCD-1-9B, DMS-20LCD-1-9, DMS-20LCD-1-5B Datasheet (DATEL)

DATEL, Inc., Mansfield, MA 02048 (USA) • Tel: [phone] Fax: [phone] • Email: [e-mail] • Internet: www.datel.com

Features

Figure 1. DMS-20LCD Series Simplified Schematic

DMS-20LCD Series, 3½ Digit, LCD Display, Digital Voltmeters represent the
ultimate combination of low price, low power, small size and high performance in digital
meters. Epoxy encapsulated in a subminiature (1.38" x 0.88" x 0.43"), 12-pin DIP
package, these completely self-contained, fully operational meters offer a combination
of ruggedness, long-term reliability and component-like ease-of-use simply not
available in any other meters.

Incorporating a precision reference and a factory-calibrated, autozeroing A/D
converter, DMS-20LCD meters are extremely accurate (±1 count) and are only slightly
larger than their 0.37"/9.4mm, enhanced-contrast, LCD displays. All models incorpo­rate a built-in bezel and are easily mounted in either panels or pc boards. Both backlit
and non-backlit versions are available.

DMS-20LCD meters have 4 differential input voltage ranges (±200mV, ±2V, ±20V
and ±200V) and a user-friendly input structure. Input impedance is a minimum 800kΩ.
CMRR is typically 86dB with a CMV of ±2V. Non-inverting inputs are overvoltage
protected to ±100V (±250V for the ±200V input model).

All DMS-20LCD meters operate from a single +5V supply (drawing 400µA) or a
single +9V supply/battery (drawing 230µA). All models have a low-battery ("B")
annunciator and feature autopolarity changeov er and overrange indication.

Also available is an application/evaluation board (DMS-EB2) that plugs directly onto
the back of any DMS-20LCD allowing direct inputs for common applications such as
4-20mA inputs, zero/gain adjust, decimal point location, and input voltage dividing.

••

••

•

Lowest cost

••

••

•

Lowest power, 2mW

••

••

•

Subminiature size:

1.38" x 0.88" x 0.43"
35mm x 22mm x 11mm

••

••

•

Large (0.37"/9.4mm), enhanced­contrast LCD display

••

••

•

Backlit displays optional

••

••

•

Epoxy-encapsulated, 12-pin DIP

••

••

•

Panel or pc-board mountable

••

••

•

4 differential input voltage ranges

••

••

•

High accuracy, ±1 count (±0.05%)

••

••

•

Single +5V supply or 9V battery

••

••

•

Low-battery annunciator

••

••

•

User-selectable decimal point placement

••

••

•

0 to +60°C temperature range

3½ Digit, LCD Display

Low-Cost, Subminiature

Digital Panel Voltmeters

DMS-20LCD Series

Actual Size

(+) INPUT HI

(–) INPUT LO

ANALOG
COMMON

REFERENCE OUT

REFERENCE IN

+5V SUPPLY/

+BATTERY

R1

DP 1

DP 2

DP 3

6

5

4

9

11

12

10

8

7

1

3

DC/DC

CONVERTER

2

5V RETURN/

–BATTERY

+5V

–5V

R2

»

+2.0V

DATA

909k

V+

V–

A/D

CONVERTER

0 Vdc

0.01µF

N.C.

R2 is not used on ± 2 0 0 mV (-0) models or ±2V (-1) models.
R2 = 100k on ±20V (-2) models and 9.1k on ±200V (-3) models.

J1

DC/DC converter is not used on 9V-powered models,
J1 is connected.

N.C./BACKLIGH T

Used on backlit models only.
N.C. for non-backlit models.

+5V

Only used on ±200mV (-0) and ±2V (-1) models.

1

2

3

1

2

4

3

4

®®

www.datel.com

2

DMS-20LCD

3½ DIGIT, LCD DISPLAY DIGITAL PANEL VOLTMETERS

Performance/Functional Specifications

Typical at TA = +25°C and supply voltage = +5V (using the single-ended input circuit) or +9V
(using the differential input circuit), unless otherwise noted.

➀

Applies for transient or continuous overvoltages applied to (+) INPUT
HI (pin 11) with (–) INPUT LO (pin 12) properly connected. Pin 12 is
not overvoltage protected (see Figure 1). Voltages applied to pin 12
should not exceed the supply voltage.

➁

Listed spec applies to 5V-powered models only. For 9V-powered
models, both (–) INPUT LO (pin 12) and (+) INPUT HIGH (pin 11)
must always be at least 1.5V above –BATTERY (pin 3) and at least

1.5V below +BATTERY (pin 1).

➂

See Technical Notes.

Leave blank for standard
models.
Add B for backlit models.

DMS-20LCD -1- 5

Accessories:

DMS-20-CP Panel cutout punch
DMS-BZL3 DMS-20 bezel assembly
DMS-BZL4 DMS-20 bezel assembly with sealing gasket
DMS-EB2 Application/evaluation board with standard

MOLEX connector, decimal point solder pads
and attenuation resistor pads.

Input Range:

0 = ±200mV
1 = ±2V
2 = ±20V
3 = ±200V

Power Source:

5 = +5V
9 = +9V

T echnical Notes

1. REFERENCE OUTPUT (Pin 8) and INPUT (Pin 7): Pin 8 is a

precision reference actively trimmed at the factory. In normal
operation, pin 8 must be tied to pin 7 to achieve all listed accuracy
and drift specifications.

2. ANALOG COMMON (Pin 10): This pin is connected to an
internal, low-noise, "relative" ground. It is used in certain
differential and "floating" measurements as described in the
Applications section of this data sheet and Ap Note 3 of the DATEL
Panel Meter Catalog. Pin 10 should not be connected to pin 3

(5V RETURN/–BATTERY) or to your system's analog ground.

3. Decimal Point Placement: The location of the decimal point is

user-selectable, and the decimal point control pins (DP1-DP3) are
active low functions. Select the appropriate decimal point by tying
the appropriate pin (pin 4, 5 or 6) to pin 3 (5V RETURN/
–BATTERY). Unused decimal point location pins should be left
open. For 5V-powered models, the decimal location pins are TTL
compatible and may be hard wired as described above or driven
with 5V TTL logic gates.

Ordering Information

A panel-mount retaining clip is supplied with each model.

Analog Inputs Min. Typ. Max. Units
Full Scale Input Range:

DMS-20LCD-0 -- ±200 -- mV
DMS-20LCD-1 -- ±2 -- Volts
DMS-20LCD-2 -- ±20 -- Volts
DMS-20LCD-3 -- ±200 -- Volts

Input Impedance:

DMS-20LCD-0, -1 100 1000 -- M

Ω

DMS-20LCD-2, -3 0.8 1 -- M

Ω

Overvoltage Protection:

➀

DMS-20LCD-0, -1, -2 -- -- ±100 Volts
DMS-20LCD-3 -- -- ±250 Volts

Common Mode Voltage Range

➁

-- -- ±2 Volts

CMRR (dc to 60Hz) -- 86 -- dB
Control Inputs ➂
Decimal Point Placement (Pins 4-6):

Functionality Tie to pin 3 to activate
Logic Compatibility TTL (on 5V-powered models)

Backlight (Pin 9) Tie to pin 3 to turn on backlight
Performance
Sampling Rate 2.5 samples per second
Accuracy (1 minute warm-up):

DMS-20LCD-0 (VIN = +0.19V) -- ±1 ±2 Counts
DMS-20LCD-1 (VIN = +1.9V) -- ±1 ±2 Counts
DMS-20LCD-2 (VIN = +19V) -- ±2 ±3 Counts
DMS-20LCD-3 (VIN = +190V) -- ±2 ±3 Counts

Zero Reading (VIN = 0 Volts) "–001" "000" "001"
Temperature Drift (0 to +60°C) -- ±0.2 ±0.4 Cnts/°C
Power Supply Requirements (5V Models)
Supply Voltage +4.75 +5.00 +5.25 Volts
Supply Current:

Standard Models -- +400 +600 µA
Backlit Models -- +35 + 50 mA

Power Supply Requirements (9V Models)
Supply Voltage +7.5 +9.0 +14.0 Volts
Supply Current:

Standard Models -- +230 +350 µA
Backlit Models -- +35 +50 mA

Display
Display Type and Size 3½ Digit LCD, 0.37"/9.4mm high
Polarity Indication Autopolarity ("–" for negative VIN)
Overrange Indication "–1__ _" for negative VIN

"1___" for positive VIN

Physical/Environmental
Operating Temperature 0--+60°C
Storage Temperature –20 -- +75 °C
Humidity (Non-condensing) 0 -- 95 %
Case Material Polycarbonate
Weight 0.4 ounces (11 grams)

Order on-line at www.datel.com

3

3½ DIGIT, LCD DISPLAY DIGITAL PANEL VOLTMETERS

DMS-20LCD

DMS-20LCD meters are availab le in either 5V-powered or 9V­powered models. 9V devices operate directly from 7.5V to 14V
supplies (usually batteries) without the need for external voltage
regulators. 9V devices, however, can not be used to measure
voltages referenced to the negative battery terminal (pin 3) because
the minus input to the meter (pin 12, (–) INPUT LO) must always be
at least 1.5V above pin 3. 9V-powered meters can only be used to
make differential and not single-ended measurements.

5V-powered devices operate from any well-regulated +5V supply
and will accurately measure voltages both above and below pin 3
(5V RETURN) in either single-ended or differential configurations.

1. Single-Ended Input Configurations: True single-ended
measurements can only be made with 5V-powered meters.
The circuit of Figure 2 avoids problems normally associated
with ground-loop currents. Separate ground runs should be
used for 5V RETURN (pin 3) and (–) INPUT LO (pin 12).

8. Suggested Mating Connectors:

Panel mounted:

Connector housing DATEL P/N 39-2079400
Terminal type DATEL P/N 39-2099090
Crimping tool DATEL P/N 39-2099000
Wire size 22 to 26 AWG
Insulation diameter 0.062" (1.57mm) maximum
Stripping length 0.100 to 0.125" (2.54 to 3.17mm)

Board mounted:

Socket DATEL P/N 39-2359625

Applications

Figure 2. Single-Ended Input Configuration

(5V- Powered Models)

RSeries = Ohms

+12.6 – 9.2V

0.035

Example: If +BATTERY (pin 1 with respect to pin 3) is +12.6V,

+BATTERY – 9.2V

0.035

R

Series = Ohms

RSeries = 97 Ohms

5. Low Battery Annunciator: The "B" annunciator in the upper
left-hand corner of the display turns on when the supply voltage
for 5V-powered models falls below approximately +3.75V or
when the supply voltage for 9V-powered models falls below
approximately 7.2V. This function can not be disabled.

6. Gain Adjust: There is a gain-adjust potentiometer on the back
of each meter. It has approximately ±50 counts (±2.5%) range of
adjustment. Since these devices essentially have no zero/offset
errors, a gain adjustment is effectively an overall accuracy
adjustment. Though they may be performed at any point (except
zero), accuracy adjustments are most effective when performed
with higher level input signals. The circuit shown in Figure 9
provides ±10% range of adjustment.

7. Soldering Methods: All models in the DMS-20LCD Series
easily withstand most common wave soldering operations. We
recommend, however, that you evaluate the effects your
particular soldering techniques may have on the meter's plastic
case and high-precision electrical performance. We recommend
the use of water-soluble solders and thorough cleaning
procedures.

4. BACKLIGHT (Pin 9) Function: Grounding pin 9 (i.e . connecting
it to pin 3) turns on the backlighting LED's. For non-backlit
models, pin 9 has no internal connection. All backlit models
include internal current-limiting resistors. With nominal +5V or
9V supplies, backlit devices typically draw 35mA of supply
current. The current drawn by the backlight (and therefore the
current drawn by the meter) can be reduced by installing a 1/4
Watt resistor between pins 3 and 9. The brightness of the meter
will be reduced proportionately.

9V-powered backlit models function with supply voltages up to
+14V, however, activating the backlight with voltages greater than

9.2V can damage the meter. Therefore, a 1/4 Watt series resistor
must be installed between pins 3 and 9 in these situations. The
value of the series resistor is determined using the following
formula:

1

12

3

+5V SUP

(–) IN LO

5V RET

DATEL

UPA-5/500

120 VAC

11

(+) IN HI

6

DP1

+

–

AC to DC Converter

V

IN

DMS-20LCD-1-5

7

REF OUT

REF IN

8

4

DMS-20LCD

3½ DIGIT, LCD DISPLAY DIGITAL PANEL VOLTMETERS

R2

R1 + R2

x VIN = Reading

50k

Ω

< R1 + R2 < 10M

Ω

4. Floating Signal Source Measurements: Floating signals can
be measured using the circuits shown in Figures 5 and 6. Figure
5 uses a 5V-powered meter. Figure 6 uses a 9V-powered meter.
Connecting pin 10 (ANALOG COMMON) to (–) INPUT LO (pin

12) provides the reference point for the meter's input.
A "floating" input is a signal that has no galvanic connection to

the meter's power supply. In the figures below, the 1.5V battery
illustrates a true floating input.

Figure 3. Differential Input Configuration

(5V-Powered Models)

5. Process Control (4-to-20mA) Measurements: In many

common process-control applications, a 4-to-20mA current loop
is used to transmit information. Because DMS-20LCD meters
have such high input impedance, a simple shunt resistor across
the meter's input can be used to convert the loop current to a
voltage. See Figure 7. The value of the shunt resistor is a

Figure 6. Floating Input Measurements

(9V-Powered Models)

Figure 5. Floating Input Measurements

(5V- Powered Models)

Figure 4. Input Attenuation Circuit

Applications

2. Differential Input Configurations: Differential measurements

can be made with either 5V -po wered or 9V-powered meters.
Figure 3, though not a practical real-world application, uses a
voltage divider to demonstrate the concept of a differential input
signal. Be careful not to exceed the ±2V common mode voltage
limitation for 5V powered meters.

3. Engineering Scaling: For measuring voltages greater than the
full scale input range of a given meter, the input signal must be
attenuated. A simple voltage divider (similar to that shown in
Figure 4) will scale the input to within the range of the selected
meter. R1 and R2 should be precision, ±1%, metal-film resistors
with absolute TCR's less than 50ppm/°C . See Ap Note 4 for more
information on engineering scaling.

1

12

3

+5V SUP

(–) IN LO

5V RET

DATEL

UPA-5/500

120 VAC

11

(+) IN HI

6

AC to DC Converter

R2

R1

R3

1k

1k

1k

8

7

REF IN

DP1

REF OUT

DMS-20LCD-1-5

R2

11

12

(+) IN HI

(–) IN LO

V

IN

R1

+

–

13

+5V SUP 5V RET

DATEL

UPA-5/500

120 VAC

AC to DC Converter

8

7

REF OUT

REF IN

DMS-20LCD-1-5

1

3

+5V SUP 5V RET

DATEL

UPA-5/500

120 VAC

6

DP1

AC to DC Converter

12

(–) IN LO

11

(+) IN HI

1.5V

CELL

+

–

8

7

REF OUT

REF IN

DMS-20LCD-1-5

13

+ BAT

–BAT

9V

BATTERY

6

DP1

12

(–) IN LO

10

ANA COMM

11

(+) IN HI

1.5V

CELL

+

–

+

–

8

7

REF OUT

REF IN

DMS-20LCD-1-5

5

3½ DIGIT, LCD DISPLAY DIGITAL PANEL VOLTMETERS

DMS-20LCD

To calibrate the circuit of Figure 7, perform the following:

1. With 4mA applied, adjust the 50kΩ potentiometer (R2) to
display a reading of "000" (assuming that is the desired
reading).

2. With 20mA applied, adjust the gain-adjust potentiometer on
the back of the meter to display a reading of "1999". For different
full scale readings, alter the value of R

Shunt accordingly.

RShunt = R1 = VFsr/IFsr

Where: VFsr = Full scale reading (in Volts)

I

Fsr = Relative full scale current (in Amps)

Example: For a meter with a 2V full scale input (1.999 full
scale reading) and a desired full scale display reading of
1000 (with an input of 20mA), V

Fsr = 1.000 Volts

R

Shunt = 1.000V/(0.020 – 0.004)A

R

Shunt = 1.000V/0.016A = 62.5 Ohms

function of the scaling requirements of the particular application and
can be calculated using the following equation:

Figure 7. 4-to-20mA Current Loop Operation

(5V- Powered Models)

R2
(R1 + R2 + R3)

= 0.1

6. Power Supply Monitoring: A popular application for DATEL's
low-power LCD meters is monitoring the supply voltage in battery­operated portable equipment. Figure 8 demonstrates how a 9V­powered DMS-20LCD can be used to monitor its own supply. The
meter used is the DMS-20LCD-1-9. A three-resistor voltage
divider is used to attenuate the battery voltage and also to satisfy
the requirement that the input voltages applied to pins 12 and 11
be at least 1.5 Volts above and below the battery voltage applied
to pins 1 (+BATTERY) and 3 (–BATTERY). The divider should be
designed so that 1/10th the battery voltage falls across the inputs
to the meter:

Therefore, the 9V battery voltage appears to the meter inputs
as 0.9V. With the decimal point moved to its DP2 position
(pin 5 tied to pin 3), the meter reads 9.00 Volts.

The circuit can be calibrated by first measuring the actual
battery voltage with another meter and then adjusting the gain­adjust potentiometer on the back of the DMS-20LCD until a
similar reading is obtained. If possible, the resistors in the
divider should be ±1% metal-film types with TCR's less than
50ppm/°C.

7. External Gain Adjustment: Connect REFERENCE OUT
(pin 8) to REFERENCE IN (pin 7) for normal, factory calibrated,
operation. Use the circuit shown in Figure 9 for applications
needing external gain adjustment. Calibration is performed with
a precise, near-full-scale, input voltage.

Figure 9. External Gain Adjustment

Figure 8. Power Supply Monitor

(9V- Powered Models)

Applications

13

+5V SUP 5V RET

DATEL

UPA-5/500

120 VAC

AC to DC Converter

12

(–) IN LO

10

ANA COMM

11

(+) IN HI

R1

+

–

4

-20mA

50k

R2

8

7

REF OUT

REF IN

DMS-20LCD-1-5

1

12

3

+BAT

(–) IN LO

–BAT

11

(+) IN HI

5

DP2

DMS-20LCD-1-9

R2

R1

R3

45.3k

10.1k

45.3k

9V

BATTERY

+

–

8

7

REF OUT

REF IN

12

VOLTAGE

CALIBRATOR

OUT

10

(+) IN HI

(–) IN LO

ANA

COMM

= 10 to 20 Turns

7

REF

IN

11

732, 1%

8.06k, 1%

5V RET/
–BAT IN

Connections

for ±2V, ±20V

and ±200V model

s

Connections

for ±200mV

models

COM

1

+5V IN/

+BAT IN

17.4k, 1%

2k

24.3k, 1%

3

12

DMS-20LCD

For +5V models, tie (–) IN LO to pin 3.
For +9V models, tie (–) IN LO to pin 10

8

NC

200

Q

Q

Q

DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151
Tel: [phone] [phone] Fax: [phone]
Internet: www.datel.com Email: [e-mail]
Data sheet fax back: [phone]

DATEL (UK) LTD. Tadley, England Tel: [phone]
DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: [phone]
DATEL GmbH München, Germany Tel: [phone]
DATEL KK Tokyo, Japan Tel: [phone], Osaka Tel: [phone]

DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein
do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark.

®®

ISO 9001

ISO 9001

REGISTERED

DS-0291B 1/98

DMS-20LCD

3½ DIGIT, LCD DISPLAY DIGITAL PANEL VOLTMETERS

Mechanical Specifications

MECHANICAL DIMENSIONS: Inches (mm)
TOLERANCES: 2 PL DEC ±0.02 (±0.51)

3 PL DEC ±0.010 (±0.254)
LEAD DIMENSIONS: 0.025 (0.635) x 0.025 (0.635) NOMINAL
RECOMMENDED PC BOARD FINISHED HOLE DIAMETER:

0.042 ±0.003 (1.067 ±0.076)

MADE IN USA

DMS-20LCD-X-XX

FRONT VIEW

DP1 DP2 DP3

PIN #1

IDENTIFIER

+5V SUPPLY/ +BATTERY

N.C.

5V RETURN/ –BATTERY

DP3
DP2
DP1

1
2
3
4
5
6

(–) INPUT LO
(+) INPUT HI
ANALOG COMMON
N.C./BACKLIGHT
REFERENCE OUT
REFERENCE IN

12
11
10

9
8
7

0.80

(20.3)

0.15
(3.8)
TYP.

0.50

(12.7)

0.10
(2.5)
TYP.

0.040
(1.02)

0.040
(1.02)

1.10

(27.9)

0.10
(2.5)
TYP.

0.25

(6.4) TYP.

0.425

(10.80)

0.040
(1.02)

1.30

(33.0)

1.38

(35.1)

0.88

(22.3)

®®

0.160
(4.06)

0.160
(4.06)

PIN 1

CALIBRATION POTENTIOMETER HOLE LOCATION

0.125 (3.175) DIAMETER
(USE ONLY WHEN PC
BOARD MOUNTING)



BEZEL INSTALLATION





#2-56 INSERT

0.156 (3.96) DEEP

FRONT VIEW

1.280

(32.51)

0.187

(4.75)

OPTIONAL BEZEL (DMS-BZL3 and DMS-BZL4)

RECOMMENDED DRILL AND PANEL CUTOUT DIMENSIONS

1.826 (46.38)

0.838

(21.29)

1.336 (33.93)

1.626 (41.30)

1.07

(27.18)

INTERNAL CORNER RADII:

0.032 (0.81) MAX.

0.145
(3.68)

0.093 (2.362) DIAMETER (4 REQUIRED)
ONLY WHEN USING OPTIONAL BEZEL ASSEMBLY

0.116

(2.95)



RETAINING CLIP INSTALLATION

