www.murata-ps.com
www.murata-ps.com/support
For full details go to
www.murata-ps.com/rohs
DMS-40LCD Series
4½ Digit, LCD Display Digital Panel Voltmeters
MPM_DMS40LCD.D01 Page 1 of 6
Offering a unique combination of low cost, scientifi c-grade accuracy (±2 counts),
component-like convenience and outstanding reliability, DMS-40LCD Series 4½ 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 confi guration
(±200mV/±2V, ±2V/±20V or ±20V/±200V) and is available with a backlit or non-backlit
display. Input impedance is a minimum 800kΩ, 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 (draw-
ing 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-cal-
ibrated A/D converters, DMS-40LCD meters are able to withstand the harshest environ-
ments and never require adjustment or calibration. Plug-in convenience, long-term stability
and wide operating temperature range (0 to +50°C) make DMS-40LCD meters the right
solution for any high-accuracy DPM requirement.
FEATURES
Scientifi c-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 +50°C temperature range
Low Cost
SIMPLIFIED SCHEMATIC DIAGRAM
(+) INPUT HI
ANALOG
(–) INPUT LO
COMMON
REFERENCE
IN/OUT
R1
DP 1
DP 2
DP 3
6
5
4
+5V SUPPLY/
+BATTERY
9
11
12
10
8
7
1
3
DC/DC
CONVERTER
2
5V RETURN/
+5V
–BATTERY
–5V
+5V
R2
REF.
1.23V
DATA
≈+2.2V
V+
V–
A/D
CONVERTER
0 Vdc
0.01µF
J1
BA
BAT
T
HOLD/
BACKLIGHT
DC/DC converter is not used on 9V-powered models,
J1 is connected.
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.
RANGE
DP 4
SELECT
Hold function is not available on backlit models.
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DMS-40LCD Series
4½ Digit, LCD Display Digital Panel Voltmeters
MPM_DMS40LCD.D01 Page 2 of 6
TECHNICAL NOTES
DMS-40LCD - 0/1 - 5 -C
➀ 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.
➁ 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.
➂ 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).
➃ See Technical Notes.
Performance/Functional Specifi cations
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.
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 Specifi cations 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 deci-
mal 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.
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-C DMS-40 bezel assembly
DMS-BZL2-C DMS-40 bezel assembly with sealing gasket
DMS-EB-C Application/evaluation board with standard
MOLEX connector, decimal point solder pads
and attenuation resistor pads.
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: ➀
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 Impedence:
DMS-40LCD-0/1 100 1000 MΩ
DMS-40LCD-1/2 0.8 1 – MΩ
DMS-40LCD-2/3 0.8 1 – MΩ
Overvoltage Protection ➁– – ±250 Volts
Common Mode Voltage Range ➂– – ±2 Volts
CMRR (dc to 60Hz) – 86 – dB
Control Inputs ➃
Decimal Pt. Placement (Pins 4-6, 8):
Functionality
Logic Compatibility
Tie to pin 3 to activate
TTL (on 5V-powered models)
Hold/Backlight Functionally (Pin 9)
Backlit Models
Non-backlit Models
Tie to pin 1 to activate
Tie to pin 3 to hold reading
Performance
Sampling Rate 2.5 reading per second
Accuracy (1 minute warm-up):
DMS-40LCD-0/1 (Vin = +0.19/1.9V) – ±2 ±3 Counts
DMS-40LCD-1/2 (Vin = +1.9V) – ±2 ±3 Counts
DMS-40LCD-1/2 (Vin = +19V) – ±3 ±4 Counts
DMS-40LCD-2/3 (Vin = +19/190V) – ±3 ±4 Counts
Zero Reading (Vin = 0 Volts) “–001” “000” “001”
Temperature Drift (0 = +50°C)
DMS-40LCD-0/1
DMS-40LCD-1/2
DMS-40LCD-2/3
–
–
–
±0.4
±0.6
±0.6
±0.8
±1
±1
Cnts/°C
Cnts/°C
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 +9.00 +14.0 Volts
Supply Current:
Standard Models – +1.5 +2.5 mA
Backlit Models – +37 +45 mA
Display
Display Type and Size 4½ digit, 0.4"/10.2mm high LCD
Polarity Indication Autopolarity ("–" for negative Vin)
Overrange Indication "–1_ _ _ _ " for negative inputs
"1_ _ _ _ " for positive inputs
Ordering Information
Add -C for RoHS
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)
See www.murata-ps.com/dpm-availability for model-specifi c availability.
www.murata-ps.com/support
DMS-40LCD Series
4½ Digit, LCD Display Digital Panel Voltmeters
MPM_DMS40LCD.D01 Page 3 of 6
APPLICATIONS
1. Single-Ended Input Confi gurations: 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 ac-
curately measure voltages both above and below pin 3 (5V RETURN) in either
single-ended or differential confi gurations.
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 recom-
mend the use of no-clean solders.
9. Suggested Mating Connectors:
Panel mounted:
Connector housing Murata Power Solutions P/N 4320-01069-0
Terminal type Murata Power Solutions P/N 4400-01032-0
Crimping tool Murata Power Solutions 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 Murata Power Solutions P/N 4320-01074-0
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 “fl oating” measurements as described in
the Applications section of this data sheet and Ap Note DMS-AN3 at
http://www.murata-ps.com/data/meters/dms-an3.pdf. 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 refer-
ence and is used during the factory calibration procedure. Pin 7 should be
left open in most common applications. It can be used in certain “ratiometric”
applications in which it is desireable for the meter’s reference to track an
external reference.
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.
RSeries = Ohms
+12.6 – 9.2V
0.035
RSeries = Ohms
+BATTERY – 9.2V
0.035
Example: If +BATTERY (pin 1 with respect to pin 3) is +12.6V,
RSeries = 97 Ohms
Figure 2. Single-Ended Input Confi guration
(5V-Powered Models)
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 the approximate range of 2.7V to 3.7V, or when the
supply voltage for 9V-powered models falls below the approximate range of
5.4 to 7.2V. This function can not be disabled.
Please note, the “BAT” annunciator is a convenience feature only. The supply
voltage ranges specifi ed previously in the ‘Performance/Functional Specifi ca-
tions’ section of this data sheet must be maintained at all times in order to
ensure the DMS-40LCD meets its accuracy and stability specifi cations.
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:
1
12
3
+5V SUP
(–) IN LO
5V RET
120 VAC
11
(+) IN HI
6
DP1
+
–
AC to DC Converter
V
IN
DMS-40LCD-0/1-5
2
RANGE
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DMS-40LCD Series
4½ Digit, LCD Display Digital Panel Voltmeters
MPM_DMS40LCD.D01 Page 4 of 6
APPLICATIONS
2. Differential Input Confi gurations: 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 demon-
strate 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 fi gures
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 “fl oating” input is a signal that has no galvanic connection to the
meter’s power supply. In the fi gures below, the 1.5V battery illustrates a
true fl oating input.
Figure 5. Floating Input Measurements
(5V-Powered Models)
Figure 6. Floating Input Measurements
(9V-Powered Models)
Figure 3. Differential Input Confi guration
(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 fi lm resistors with absolute TCR’s less than
50ppm/°C. See Ap Note 4 for more information on engineering scaling.
50kΩ < R1 + R2 < 10MΩ
R2
R1 + R2
x VIN = Reading
Figure 4. Input Attenuation Circuit
–
R2
11 12 3
(+) IN HI (–) IN LO 5V RET
V
IN
R1
+
DMS-40LCD-0/1-5
13
+ BAT
9V
–BAT
6
BATTERY
DP1
2
12
RANGE
10
(–) IN LO
ANA COMM
11
(+) IN HI
CELL
1.5V
+
–
+
–
DMS-40LCD-0/1-9
1
12
3
+5V SUP
(–) IN LO
5V RET
120 VAC
11
(+) IN HI
6
DP1
AC to DC Converter
R2
R1
R3
1k
1k
1k
2
RANGE
DMS-40LCD-0/1-5
13
5V RET+5V SUP
6
DP1
120 VAC
AC to DC Converter
2
12
RANGE
10
(–) IN LO
ANA COMM
11
(+) IN HI
CELL
1.5V +
–
DMS-40LCD-0/1-5
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DMS-40LCD Series
4½ Digit, LCD Display Digital Panel Voltmeters
MPM_DMS40LCD.D01 Page 5 of 6
APPLICATIONS
6. Power Supply Monitoring: A popular application for Murata Power
Solutions’ 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 confi gured 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 fi rst measuring the actual battery volt-
age with another meter and then adjusting the gain-adjust potentiom-
eter on the back of the DMS-40LCD until a similar reading is obtained.
If possible, the resistors in the divider should be ±1% metal-fi lm types
with TCR’s less than 50ppm/°C.
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)
To calibrate the circuit of Figure 7, perform the following:
1. With 4mA applied, adjust the 50kΩ 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 RShunt
accordingly.
R
Shunt = 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), VFsr = 1.000 Volts
R
Shunt = 1.000V/(0.020 – 0.004)A
R
Shunt = 1.000V/0.016A = 62.5 Ohms
1
12
3
+BAT –BAT
11
(–) IN LO
5
(+) IN HI
DP2
R2
R1
R3
45.3k
2
10.1k
RANGE
9V
45.3k
BATTERY
+
–
DMS-40LCD-0/1-9
31
+5V SUP 5V RET
120 VAC
AC to DC Converter
2
12
RANGE
10
(–) IN LO
ANA COMM
11
R1
(+) IN HI
+
–
4-20mA
50k
R2
DMS-40LCD-0/1-5
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Murata Power Solutions, Inc. 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. Specifi cations are subject to change without
notice. © 2015 Murata Power Solutions, Inc.
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfi eld, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
This product is subject to the following operating requirements
and the Life and Safety Critical Application Sales Policy:
Refer to: http://www.murata-ps.com/requirements/
DMS-40LCD Series
4½ Digit, LCD Display Digital Panel Voltmeters
MPM_DMS40LCD.D01 Page 6 of 6
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)
BEZEL INSTALLATION AND RECOMMENDED DRILL AND PANEL CUTOUT
MADE IN USA
BEZEL INSTALLATION
PANEL
BEZEL
#2-56 INSERT
FRONT VIEW 0.156 (3.96) DEEP
1.270
(32.26)
0.187
(4.75)
2.35 (59.69)
2.118 (53.80)
RECOMMENDED DRILL AND PANEL CUTOUT DIMENSIONS
0.093 (2.362) DIAMETER (4 REQUIRED)
ONLY WHEN USING OPTIONAL BEZEL ASSEMBLY
INTERNAL CORNER RADII:
1.07
0.032 (0.81) MAX.
(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 IN USADMS-40LCD-X/X-XX
FRONT VIEW
+5V SUPPLY/ +BATTERY
RANGE SELECT
DP3
5V RETURN/ –BATTERY
DP2
DP1
1
2
3
4
5
6
(–) INPUT LO
(+) INPUT HI
ANALOG COMMON
DP4
HOLD/BACKLIGHT
12
11
10
9
8
7REFERENCE IN/OUT
DP1 DP2 DP3 DP4
2.17
(55.1)
2.09
(53.1)
1.80
(45.7)
0.15
(3.7)
0.25 (6.4) TYP.
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
PIN #1
(23.4)
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
0.040
(1.02)
0.125 (3.175) DIAMETER
(USE ONLY WHEN PC BOARD MOUNTING)
