DATEL, Inc., Mansfield, MA 02048 (USA)
Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356
Email: sales@datel.com
Internet: www.datel.com
4 Digit, LCD Display
Low-Power, Miniature
Digital Panel Voltmeters
DMS-40LCD Series
Figure 1. DMS-40LCD Series Simplified Schematic
Scientific-grade accuracy, 2 counts
Low power, typically 12.5mW
Miniature size:
2.17" x 0.92" x 0.43"
55mm x 23mm x 11mm
Large (0.4"/10.2mm), enhanced-
contrast, LCD display
Backlit displays optional
Epoxy-encapsulated, 12-pin DIP
Panel or pc-board mountable
3 differential, dual, input voltage ranges
Single +5V supply or 9V battery
User-selectable decimal point placement
Low-battery "BAT" annunciator
0 to +50C temperature range
Low Cost
Offering a unique combination of low cost, scientific-grade accuracy (2 counts),
component-like convenience and outstanding reliability, DMS-40LCD Series 4 Digit
DPM's provide the ultimate combination of price, precision and convenience. These
miniature (2.17" x 0.92" x 0.43") digital voltmeters combine an advanced, autozeroing
A/D converter, a precision reference circuit and a large (0.4"/10.2mm high), easy-to-
read LCD display in a single, fully encapsulated, 12-pin DIP package. All models
incorporate a built-in bezel and are easily mounted in either panels or pc boards.
Each DMS-40LCD meter has a dual-range, differential, input configuration
(200mV/2V, 2V/20V or 20V/200V) and is available with a backlit or non-backlit
display. Input impedance is a minimum 800k
, and CMRR is typically 86dB (dc to
60Hz). CMV is 2V, and all models are overvoltage protected to 250V (on their non-
inverting inputs).
All DMS-40LCD meters are fully functional and operate from a single +5V supply
(drawing 3.5mA max.) or a single 9V supply/battery (drawing 2.5mA max.). All models
feature autopolarity changeover and overrange indication. A display HOLD function is
standard on all non-backlit models.
Thanks to their rugged epoxy-based encapsulation and their advanced, factory-
calibrated A/D converters, DMS-40LCD meters are able to withstand the harshest
environments and never require adjustment or calibration. Plug-in convenience, long-
term stability and wide operating temperature range (0 to +50C) make DMS-40LCD
meters the right solution for any high-accuracy DPM requirement.
Features
Actual Size
(+) INPUT HI
() INPUT LO
ANALOG
COMMON
REFERENCE
IN/OUT
+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
+5V
1.23V
REF.
R2
+2.2V
DATA
V+
V
A/D
CONVERTER
0 Vdc
0.01F
J1
BAT
R1 = 100k on 200mV/2V (-0/1) models and 909k on all other models.
R2 is not used on 200mV/2V (-0/1) models.
R2 = 101k on 2V/20V (-1/2) models and 9.2k on 20V/200V (-2/3) models.
HOLD/
BACKLIGHT
BAT
DC/DC converter is not used on 9V-powered models,
J1 is connected.
RANGE
SELECT
DP 4
Hold function is not available on backlit models.
www.datel.com
2
DMS-40LCD - 0/1 - 5
Each model in the DMS-40LCD Series offers two input voltage ranges
that are user-selectable via pin strapping. 5V-powered models can be
used to perform either differential or single-ended measurements. 9V-
powered models can only be used for differential measurements.
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.
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).
See Technical Notes.
Performance/Functional Specifications
Typical at T
A
= +25C and supply voltage = +5V (using the single-ended input circuit) or +9V
(using the differential input circuit), unless otherwise noted.
DMS-40LCD
Technical Notes
1. Input Voltage Range Selection:
Each model in the DMS-40LCD
Series offers two, user-selectable, input voltage ranges as
indicated in the Performance/Functional Specifications Table and
the Ordering Information. To select the higher range of any
device (such as the 2V range for the DMS-40LCD-0/1), connect
pin 2 (RANGE SELECT) to pin 1 (+5V SUPPLY/+BATTERY). To
select the lower range, leave pin 2 open.
2. Decimal Point Placement:
The location of the decimal point is
user-selectable, and the decimal point control pins (DP1-DP4)
are active low functions. Select the appropriate decimal point by
tying the appropriate pin (pin 4, 5, 6 or 8) 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.
3. Low Battery Annunciator:
The "BAT" 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 approxi-
mately 7.2V. This function can not be disabled.
Leave blank for standard
models.
Add
B
for
backlit models.
Power Source:
5
= +5V
9
= +9V
Accessories:
DMS-30-CP
Panel cutout punch
DMS-BZL1
DMS-40 bezel assembly
DMS-BZL2
DMS-40 bezel assembly with sealing gasket
DMS-EB
Application/evaluation board with standard
MOLEX connector, decimal point solder pads
and attenuation resistor pads.
DMS-PS1-CM
+5V/1.0A AC/DC power supply module
4 D I G I T , L C D D I S P L A Y D I G I T A L P A N E L V O L T M E T E R S
Ordering Information
Input Ranges:
0/1
= 200mV/2V
1/2
= 2V/20V
2/3
= 20V/200V
A panel-mount retaining clip is supplied with each model.
Analog Inputs
Min.
Typ.
Max.
Units
Full Scale Input Range:
DMS-40LCD-0/1
--
200/2
--
mV/V
DMS-40LCD-1/2
--
2/20
--
V/V
DMS-40LCD-2/3
--
20/200
--
V/V
Input Impedance:
DMS-40LCD-0/1
100
1000
--
M
DMS-40LCD-1/2
0.8
1
--
M
DMS-40LCD-2/3
0.8
1
--
M
Overvoltage Protection
--
--
250
Volts
Common Mode Voltage Range
--
--
2
Volts
CMRR
(dc to 60Hz)
--
86
--
dB
Control Inputs
Decimal Point Placement
(Pins 4-6, 8):
Functionality
Tie to pin 3 to activate
Logic Compatibility
TTL (on 5V-powered models)
Hold/Backlight
Functionality
(Pin 9):
Backlit Models
Tie to pin 3 to turn on backlight
Non-backlit Models
Tie to pin 3 to hold last reading
Performance
Sampling Rate
2.5 samples per second
Accuracy
(3 minute warm-up):
DMS-40LCD-0/1 (V
IN
= +0.19/1.9V)
--
2
3
Counts
DMS-40LCD-1/2 (V
IN
= +1.9V)
--
2
3
Counts
DMS-40LCD-1/2 (V
IN
= +19V)
--
3
4
Counts
DMS-40LCD-2/3 (V
IN
= +19/190V)
--
3
4
Counts
Zero Reading
(V
IN
= 0 Volts)
"0001"
"0000"
"0001"
Temperature Drift
(0 to +50C):
DMS-40LCD-0/1
--
0.4
0.8
Cnts/C
DMS-40LCD-1/2
--
0.6
1
Cnts/C
DMS-40LCD-2/3
--
0.6
1
Cnts/C
Power Supply Requirements (5V Models)
Supply Voltage
+4.75
+5.00
+5.25
Volts
Supply Current:
Standard Models
--
+2.5
+3.5
mA
Backlit Models
--
+37
+45
mA
Power Supply Requirements (9V Models
)
Supply Voltage
+7.5
+9.0
+14.0
Volts
Supply Current:
Standard Models
--
+1.5
+2.5
mA
Backlit Models
--
+37
+45
mA
Display
Display Type and Size
4 Digit LCD, 0.4"/10.2mm high
Polarity Indication
Autopolarity ("" for negative V
IN
)
Overrange Indication
"1_ _ _ _ " for negative V
IN
"1_ _ _ _ " for positive V
IN
Physical/Environmental
Operating Temperature
0
--
+50
C
Storage Temperature
20
--
+75
C
Humidity
(Non-condensing)
0
--
95
%
Case Material
Polycarbonate
Weight
0.75 ounces (21 grams)
Order on-line at www.datel.com
2
R
Series
= Ohms
+12.6 9.2V
0.035
R
Series
= Ohms
+BATTERY 9.2V
0.035
Example: If +BATTERY (pin 1 with respect to pin 3) is +12.6V,
R
Series
= 97 Ohms
Applications
4 D I G I T , L C D D I S P L A Y D I G I T A L P A N E L V O L T M E T E R S
DMS-40LCD
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).
DMS-40LCD meters are available in either 5V-powered or 9V-
powered 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.
9. 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
4. HOLD/BACKLIGHT (Pin 9) Function:
For non-backlit models,
connecting pin 9 (HOLD/BACKLIGHT) to pin 3 (5V RETURN/
BATTERY) will hold (continuously display) the last reading.
If not used, pin 9 should be left open for these models.
For backlit models, grounding pin 9 (i.e. connecting it to pin 3)
turns on the backlighting LED's. 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:
In any backlit application, including those with supply voltages
< 9.2V, 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
backlight will be reduced proportionately.
5. ANALOG COMMON (Pin 10):
This pin is connected to an
internal, low-noise, "relative" ground. It is used in certain
"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.
6. REFERENCE IN/OUT (Pin 7):
This pin accesses the meter's
internal reference and is used during the factory calibration
procedure. Pin 7 should be left open in most common applica-
tions. It can be used in certain "ratiometric" applications in which
it is desireable for the meter's reference to track an external
reference. See the Applications section of the DATEL Panel
Meter Catalog for more details.
7. Gain Adjust:
There is a gain-adjust potentiometer on the back of
each meter. It has approximately 150 counts of adjustment
range. 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.
8. Soldering Methods:
All models in the DMS-40LCD Series
easily withstand most common wave soldering operations. We
recommend, however, 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.
Figure 2. Single-Ended Input Configuration
(5V-Powered Models)
1
1 2
3
+ 5 V S U P
( ) I N L O
5 V R E T
D A T E L
D M S - P S 1 - C M
8 5 - 2 6 4 V a c
1 1
( + ) I N H I
6
D P 1
+
A C t o D C C o n v e r t e r
V
I N
D M S - 4 0 L C D - 0 / 1 - 5
2
R A N G E
4
2. Differential Input Configurations:
Differential measurements
can be made with either 5V-powered 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.
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.
Both figures show a DMS-40LCD-0/1 with pin 2 tied to pin 1
yielding a 2V input range. 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.
DMS-40LCD
4 D I G I T , L C D D I S P L A Y D I G I T A L P A N E L V O L T M E T E R S
Figure 5. Floating Input Measurements
(5V-Powered Models)
Figure 6. Floating Input Measurements
(9V-Powered Models)
Applications
Figure 3. Differential Input Configuration
(5V-Powered Models)
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.
50k
< R1 + R2 < 10M
R2
R1 + R2
x V
IN
= Reading
Figure 4. Input Attenuation Circuit
1
1 2
3
+ 5 V S U P
( ) I N L O
5 V R E T
1 1
( + ) I N H I
6
D P 1
A C t o D C C o n v e r t e r
R 2
R 1
R 3
1 k
1 k
1 k
2
R A N G E
D M S - 4 0 L C D - 0 / 1 - 5
D A T E L
D M S - P S 1 - C M
8 5 - 2 6 4 V a c
R2
11
12
3
(+) IN HI
() IN LO
5V RET
V
IN
R1
+
DMS-40LCD-0/1-5
1
3
+ 5 V S U P
5 V R E T
6
D P 1
A C t o D C C o n v e r t e r
2
R A N G E
1 2
( ) I N L O
1 0
A N A C O M M
1 1
( + ) I N H I
1 . 5 V
C E L L
+
D M S - 4 0 L C D - 0 / 1 - 5
D A T E L
D M S - P S 1 - C M
8 5 - 2 6 4 V a c
1
3
+ BAT
BAT
9V
BATTERY
6
DP1
2
RANGE
12
() IN LO
10
ANA COMM
11
(+) IN HI
1.5V
CELL
+
+
DMS-40LCD-0/1-9
4
6. Power Supply Monitoring:
A popular application for DATEL's
low-power LCD meters is monitoring the supply voltage in
battery-operated portable equipment. Figure 8 demonstrates
how a 9V-powered DMS-40LCD can be used to monitor its own
supply. The meter used is the DMS-40LCD-0/1-9 configured for
its 2V input range (pin 2 connected to pin 1). 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 9.000 Volts.
The circuit can be calibrated by first measuring the actual battery
voltage with another meter and then adjusting the gain-adjust
potentiometer on the back of the DMS-40LCD 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.
4 D I G I T , L C D D I S P L A Y D I G I T A L P A N E L V O L T M E T E R S
DMS-40LCD
R2
(R1 + R2 + R3)
= 0.1
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-40LCD 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
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)
Figure 8. Power Supply Monitor
(9V-Powered Models)
Applications
To calibrate the circuit of Figure 7, perform the following:
1. With 4mA applied, adjust the 50k
potentiometer (R2) to
display a reading of "0000" (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 "19999".
For different full scale readings, alter the value of R
Shunt
accordingly.
R
Shunt
= R1 = V
Fsr
/ I
Fsr
Where:
V
Fsr
= 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
1
3
+ 5 V S U P
5 V R E T
A C t o D C C o n v e r t e r
2
R A N G E
1 2
( ) I N L O
1 0
A N A C O M M
1 1
( + ) I N H I
R 1
+
4 - 2 0 m A
5 0 k
R 2
D M S - 4 0 L C D - 0 / 1 - 5
D A T E L
D M S - P S 1 - C M
8 5 - 2 6 4 V a c
1
12
3
+BAT
() IN LO
BAT
11
(+) IN HI
5
DP2
R2
R1
R3
45.3k
10.1k
2
RANGE
45.3k
9V
BATTERY
+
DMS-40LCD-0/1-9
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151
Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356
Internet: www.datel.com Email: sales@datel.com
DATEL (UK) LTD. Tadley, England Tel: (01256)-880444
DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 01-34-60-01-01
DATEL GmbH Mnchen, Germany Tel: 89-544334-0
DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-6354-2025
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
R
E
G
I
S
T
E
R
E
D
DS-0283B 10/01
DMS-40LCD
4 D I G I T , L C D D I S P L A Y D I G I T A L P A N E L V O L T M E T E R S
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)
Mechanical Specifications
MA
DE IN
USA
BEZEL INSTALLATION
PANEL
BEZEL
#2-56 INSERT
0.156 (3.96) DEEP
FRONT VIEW
1.270
(32.26)
0.187
(4.75)
OPTIONAL BEZEL (DMS-BZL1 and DMS-BZL2)
2.35 (59.69)
2.118 (53.80)
0.093 (2.362) DIAMETER (4 REQUIRED)
ONLY WHEN USING OPTIONAL BEZEL ASSEMBLY
RECOMMENDED DRILL AND PANEL CUTOUT DIMENSIONS
INTERNAL CORNER RADII:
0.032 (0.81) MAX.
1.07
(27.18)
0.878
(22.30)
0.096
(2.44)
0.116
(2.95)
2.55 (64.77)
PANEL CUTOUT
RETAINING CLIP INSTALLATION
PANEL
MADE I
N US
A
DMS-
40LCD-
X/X-
XX
FRONT VIEW
+5V SUPPLY/ +BATTERY
RANGE SELECT
5V RETURN/ BATTERY
DP3
DP2
DP1
1
2
3
4
5
6
() INPUT LO
(+) INPUT HI
ANALOG COMMON
HOLD/BACKLIGHT
DP4
REFERENCE IN/OUT
12
11
10
9
8
7
DP1
DP2
DP3
DP4
2.17
(55.1)
2.09
(53.1)
1.80
(45.7)
0.25 (6.4) TYP.
0.15
(3.7)
TYP.
0.10
(2.5)
TYP.
0.040
(1.02)
0.17
(4.3)
TYP.
0.50
(12.7)
0.84
(21.3)
0.92
(23.4)
PIN #1
IDENTIFIER
0.430 (10.92) STANDARD
0.560 (14.22) BACKLIT
0.040
(1.02)
0.325
(8.26)
0.290
(7.37)
PIN 1
CALIBRATION POTENTIOMETER HOLE LOCATION
0.125 (3.175) DIAMETER
(USE ONLY WHEN PC BOARD MOUNTING)
0.040
(1.02)
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