(+) INPUT HI
(–) INPUT LO
ANALOG
COMMON
REFERENCE OUT
REFERENCE IN
+5V SUPPLY
R1
DP 1
DP 2
DP 3
6
5
4
11
12
10
8
7
1
3
DC/DC
CONVERTER
2
5V RETURN
+5V
–5V
R2
»+2.0V
DATA
909k
V+
V–
A/D
CONVERTER
0 Vdc
0.01
µF
9
DISPLAY
ENABLE
+5V
R2 is not used on ±200mV (-0) models or ±2V (-1) models.
R2 = 100k on ±20V (-2) models and 9.1k on ±200V (-3) models.
Only used on ±200mV (-0) and ±2V (-1) models.
DISPLAY
TEST/HOLD
11
Pin 9 is DISPLAY TEST on all but eight models. On those models
(-H option), it is DISPLAY HOLD.
1
2
3
2
1
3
www.murata-ps.com
www.murata-ps.com/support
For full details go to
www.murata-ps.com/rohs
DMS-20PC Series
3½ Digit, LED Display, Low-Cost, Subminiature
Digital Panel Voltmeters
MPM_DMS_20PC.F01 Page 1 of 6
DMS-20PC Series, 3½ Digit, LED Display, Digital Panel Voltmeters combine a preci-
sion A/D converter; a factory-trimmed, highly stable, voltage reference; and a large
(0.37"/9.4mm), easy-to-read LED display in a single package that is only slightly larger
than the display itself. Displays are offered in either red, orange, amber, yellow, green or
blue colors. High-intensity and low-power (35mW total) red LEDs are also optional.
These low-cost meters are fully self-contained and fully functional. Their subminiature
(1.38" x 0.88" x 0.48"), epoxy-encapsulated cases incorporate built-in color fi lters and
bezels; are moisture and vibration proof; and function well in the harshest environments.
Their 12-pin, dual-in-line confi guration offers component-like, plug-in convenience and
maximum versatility. Operating temperature range is 0 to +60°C.
The meters come with one of four, differential, input voltage ranges: ±200mV, ±2V
±20V or ±200V. Input impedance is a minimum 800kΩ. CMRR is typically 86dB (dc to
60Hz), and CMV is ±2V. Input overvoltage protection (on the non-inverting input) is ±250V.
Devices are fully calibrated at the factory to an accuracy of ±1 count (±0.05% of full scale
range) and never require calibration or adjustment.
A DISPLAY ENABLE function permits the display to be disabled for "power-down"
operation. All models have a DISPLAY TEST function. Standard red LED models offer an
optional DISPLAY HOLD function.
Small size, low cost and adjustment-free reliability make the DMS-20PC Series the best
choice for all your 3½ digit, LED, DPM applications.
FEATURES
Lowest-cost LED meters
Subminiature size:
1.38" x 0.88" x 0.48" (35mm x 22mm x 12mm)
Large (0.37"/9.4mm) LED display
Choice of 6 LED colors
High-intensity or low-power (7mA) red LEDs optional
Epoxy-encapsulated, 12-pin DIP package with built-in
color fi lter and bezel
4 differential input voltage ranges
Factory calibrated, ±1 count accuracy
Single +5V power supply
User-selectable decimal point placement
DISPLAY ENABLE function for "power-down" mode
DISPLAY TEST and HOLD (optional) functions
0 to +60°C temperature range
SIMPLIFIED SCHEMATIC DIAGRAM
Figure 1. DMS-20PC Series simplifi ed schematic
New
Low-power blue
and green LEDs
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 See Technical Notes.
➂ The DISPLAY HOLD function is optional on standard red and green LED models only.
Leave blank for standard
models.
Add -H for DISPLAY HOLD
option (available on
standard red and green
LED models only).
DMS-20PC - 1 - RS -C
LED Color:
AS = Standard Amber
BS = Standard Blue
GS = Standard Green
OS = Standard Orange
RS = Standard Red
YS = Standard Yellow
RH = High-Intensity Red
RL = Low-Power Red
BL = Low-Power Blue
PGL = Low-Power Green
Accessories:
DMS-20-CP Panel cutout punch
DMS-BZL3-C DMS-20 bezel assembly
DMS-BZL4-C DMS-20 bezel assembly with sealing gasket
DMS-EB2-C 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
A panel-mount retaining clip is supplied with each model.
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 specifi ca-
tions.
2. ANALOG COMMON (Pin 10): This pin is connected to an internal,
low-noise, "relative" ground. It is used in certain differential and
"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) 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). Unused decimal
point location pins should be left open.
Hard wiring is preferable, however, you can use logic gates to
exercise dynamic control over the location of the decimal point if the
following drive conditions are met:
Model Applied "0" Voltage Load Current*
DMS-20PC-X-XL +0.05V max. 0.7mA max.
All Others +0.4V max. 6mA max.
* The driving gates must be able to sink this much current
Analog Inputs Min. Typ. Max. Units
Full Scale Input Range:
DMS-20PC-0 – ±200 – mV
DMS-20PC-1 – ±2 – Volts
DMS-20PC-2 – ±20 – Volts
DMS-20PC-3 – ±200 – Volts
Input Impedence:
DMS-20PC-0, -1 – 1000 – MΩ
DMS-20PC-2, -3 – 1 – MΩ
Overvoltage Protection ➀ – – ±250 Volts
Common Mode Voltage Range – – ±2 Volts
CMRR (dc to 60Hz) –86–dB
Performance
Sampling Rate 2.5 reading per second
Accuracy (3 minute warm-up):
DMS-20PC-0 (Vin = +0.19V) – ±1 ±3 Counts
DMS-20PC-1 (Vin = +1.9V) – ±1 ±3 Counts
DMS-20PC-2 (Vin = +19V) – ±2 ±3 Counts
DMS-20PC-3 (Vin = +190V) – ±2 ±3 Counts
Zero Reading (Vin = 0 Volts) “–001” “000” “001”
Temperature Drift (0 = +60°C) – ±0.2 ±0.4 Cnts/°C
Power Supply Requirements
Supply Voltage +4.75 +5.00 +5.25 Volts
Supply Current:
DMS-20PC-X-RL – +7 +12 mA
DMS-20PC-X-BL & -PGL – +12 +17 mA
DMS-20PC-X-RS, -RH – +60 +90 mA
DMS-20PC-X-RS-H – +60 +90 mA
DMS-20PC-X-BS – +75 +100 mA
DMS-20PC-X-GS-H – +90 +120 mA
DMS-20PC-X-AS, -GS, -OS, -YS – +90 +120 mA
Display
Display Type and Size 3½ digit, 0.37"/9.4mm high LED
Polarity Indication Autopolarity ("–" for negative Vin)
Overrange Indication "–1_ _ _ " for negative inputs
"1_ _ _ " for positive inputs
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)
Performance/Functional Specifi cations
Typical at TA = +25°C and supply voltage = +5V using the single-ended input circuit,
unless otherwise noted.
Ordering Information
RoHS Compliant Parts: Add "-C" suffi x to part number.
Add -C for RoHS
See www.murata-ps.com/dpm-availability for model-specifi c availability.
www.murata-ps.com/support
DMS-20PC Series
3½ Digit, LED Display, Low-Cost, Subminiature
Digital Panel Voltmeters
MPM_DMS_20PC.F01 Page 2 of 6
TECHNICAL NOTES
4. DISPLAY TEST/HOLD (Pin 9) Function: Pin 9 is a dual-function
pin. On all standard models (without "-H" suffi x), tying pin 9 to pin 1
(+5V SUPPLY) activates the meter's DISPLAY TEST feature. All display
segments, except the decimal points, will be illuminated. The display
will show "1888" ("–1888" if a negative input signal is present). Do
not leave the meter in the test mode for more than 10 seconds as
this will cause the meter's operating temperature to rise and possibly
affect its performance. Pin 9 must be left open when the test function
is not being used.
On models with the "-H" suffi x (DMS-20PC-1-RS-H for example), pin
9 serves as a DISPLAY HOLD control pin. Tying pin 9 to +5V SUPPLY
(pin 1) on these models will hold or "freeze" the current display read-
ing indefi nitely. Pin 9 must also be left open when the hold function is
not being used. After disabling DISPLAY HOLD, allow the meter a full
10 seconds to resume normal calibrated operation before holding a
new reading.
The DISPLAY TEST or DISPLAY HOLD pin should normally be con-
nected, via a selector switch, to pin 1 (+5V SUPPLY). If automatic,
logic-controlled operation is desired, only PNP or MOSFET transis-
tors should be used. The base or gate of these transistors should be
driven suffi ciently hard to bring pin 9 within 0.05V of +5V SUPPLY.
5. DISPLAY ENABLE (Pin 2) Function: On all models, tying pin 2 to
pin 1 (+5V SUPPLY) applies full power to the LED display. This is the
normal mode of operating the meter. Leaving DISPLAY ENABLE open
(no connection), only turns off the LED display. The meter's analog-
to-digital converter continues to sample the input signal. Total current
consumption with the display off is approximately 400μA (0.4mA).
This is a very useful feature if the meter is used in battery-powered
equipment.
With the exception of the low-power red LED models (DMS-20PC-X-
RL), a regulated voltage lower than +5V SUPPLY can be used to dim
the display intensity. Display intensity control is best performed with
the high brightness, red LED, DMS-20PC-X-RH model. All low-power
red LED models must have DISPLAY ENABLE tied directly to pin 1
(+5V SUPPLY). Voltages applied to DISPLAY ENABLE must never be
greater than +5V SUPPLY.
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 adjust-
ment. 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 10 provides
±10% range of adjustment.
7. Soldering Methods: All models in the DMS-20PC Series easily with-
stand 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 no-clean solders.
8. 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
Figure 2. Single-Ended Input Confi guration
DMS-20PC meters are highly versatile devices that can be used in
hundreds of applications. The application circuits chosen for this section
are ones that have historically received many inquiries.
The schematic in Figure 1 shows that the meter's high-impedance input
consists of an op amp powered from a ±5Vdc power supply (the –5V is
internally generated). One can easily see why input signals applied to (–)
INPUT LO and (+) INPUT HI have to be kept within the power supply rails
of ±5V. Also note that only pin 11 has a current-limiting 909kΩ series
resistor. High input voltages that have a common ground with pin 3 (5V
RETURN) should only be applied to pin 11 ((+) INPUT HI) and never to pin
12. In these high-voltage cases, pin 12 should always be tied to pin 3
(5V RETURN).
The schematic also shows that pin 3 is the meter's zero-volt reference
point — regardless of the type of power or signal source used. This is
an important point to keep in mind when a digital or analog multimeter
is used to make system measurements. The multimeter's negative lead
(usually the black one) must be connected to pin 3 (5V RETURN).
1. Single-Ended Input Confi gurations: True single-ended measure-
ments can be made with any DMS-20PC meter. 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).
1
12
3
+5V SUP
(–) IN LO
5V RET
85-264Vac
11
(+) IN HI
6
DP1
+
–
AC to DC Converter
VIN
DMS-20PC-1
7
REF OUT
REF IN
8
2
DISPLAY
ENABLE
www.murata-ps.com/support
DMS-20PC Series
3½ Digit, LED Display, Low-Cost, Subminiature
Digital Panel Voltmeters
MPM_DMS_20PC.F01 Page 3 of 6
APPLICATIONS
Figure 3. Differential Input Confi guration
R2
R1 + R2
x VIN = Reading
50kΩ < R1 + R2 < 10MΩ
Figure 6. Floating Input Measurements
(Alternate Confi guration)
Figure 5. Floating Input Measurements
Figure 4. Input Attenuation Circuit
RShunt = R1 = VFsr /IFsr
Where: VFsr = Full scale reading (in Volts)
I Fsr = Relative full scale current (in Amps)
2. Differential Input Confi gurations: Differential measurements
can be made with all DMS-20PC meters. Figure 3, though not
a practical real-world application, uses a voltage divider to
demonstrate the concept of a differential input signal. Be care-
ful 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-fi lm resistors with absolute TCR's less than 50ppm/°C.
See Ap Note 4 for more information on engineering scaling.
4. Floating Signal Source Measurements: Floating signals can be
measured using the circuits shown in Figures 5 and 6. Connecting
pin 10 (ANALOG COMMON) or pin 3 (5V RETURN) 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.
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-20PC 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 require-
ments of the particular application and can be calculated using
the following equation:
1
12
3
+5V SUP
(–) IN LO
5V RET
11
(+) IN HI
6
AC to DC Converter
DMS-20PC-1
R2
R1
R3
1k
1k
1k
8
7
REF IN
DP1
REF OUT
2
DISPLAY
ENABLE
85-264Vac
DMS-20PC-1
R2
11
12
(+) IN HI
(–) IN LO
VIN
R1
+
–
13
+5V SUP 5V RET
AC to DC Converter
8
7
REF OUT
REF IN
2
DISPLAY
ENABLE
85-264Vac
13
+5V SUP
6
DP1
AC to DC Converter
DMS-20PC-1
12
(–) IN LO
11
(+) IN HI
1.5V
CELL
+
–
8
7
REF OUT
REF IN
2
DISPLAY
ENABLE
5V
RET
85-264Vac
DMS-20PC-1
12
(–) IN LO
10
ANA COMM
11
(+) IN HI
1.5V
CELL
+
–
8
7
REF OUT
REF IN
13
+5V SUP
6
DP1
AC to DC Converter
2
DISPLAY
ENABLE
5V
RET
85-264Vac
www.murata-ps.com/support
DMS-20PC Series
3½ Digit, LED Display, Low-Cost, Subminiature
Digital Panel Voltmeters
MPM_DMS_20PC.F01 Page 4 of 6
APPLICATIONS
http://www.murata-ps.com/data/meters/dms-an6.pdf
Figure 10. External Gain Adjustment
Figure 8. 4.5-18V Power Supply Monitor
Figure 9. Basic DC Ammeter Circuit
Figure 7. 4-to-20mA Current Loop Operation
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 "1000".
For different full scale readings, alter the value of RShunt
accordingly.
The LM-2931 was chosen because it has the following on-chip
protection features: reverse polarity, short circuit and thermal
runaway. When using other, higher-power, DMS-20PC models
with three-terminal regulators, be sure to consult the regula-
tor manufacturer's data sheet to ensure the regulator is being
utilized safely and correctly.
7. Digital Ammeter: Digital ammeters are fi nding ever-increasing
usage because analog-style ammeters (moving-vane types)
now cost roughly the same as their digital counterparts. Addi-
tionally, analog ammeters are not nearly as rugged as modern
digital panel voltmeters. Figure 9 illustrates a typical ammeter
application. The circuit uses a ±200mV input meter — the
preferred range for most ammeters — to measure the voltage
developed across a 0.1Ω current shunt. The circuit shown
represents a basic ammeter connection diagram. Click here to
view a detailed application note describing digital dc ammeters.
8. External Gain Adjustment: Connect REFERENCE OUT
(pin 8) to REFERENCE IN (pin 7) for normal, factory calibrated,
operation. Use the circuit shown in Figure 10 for applications
needing external gain adjustment. Calibration is performed
with a precise, near-full-scale, input voltage.
6. Power Supply Monitoring: One of the most common digital
panel meter applications involves monitoring the output voltage
of the system power supply — often this supply also powers the
meter itself. The low-power, red LED DMS-20PC-2-RL can be
confi gured to allow power supply monitoring over the range of
4.5-18Vdc. The circuit in Figure 8 uses a low-drop-out, three-ter-
minal regulator (LM-2931Z-5, available from National Semicon-
ductor) to provide regulated 5V-power to the meter.
Example: For a meter with a 2V full scale input (1.999 full scale
reading) and a desired 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
13
+5V SUP 5V RET
AC to DC Converter
DMS-20PC-1
12
(–) IN LO
10
ANA COMM
11
(+) IN HI
R1
+
–
4-20mA
50k
R2
8
7
REF OUT
REF IN
2
DISPLAY
ENABLE
85-264Vac
5
78
+
–
DMS-20PC-2-RL
12
11
1
4.5 - 18Vdc
LM2931Z-5
GND
IN OUT +5V SUP
3
DP2
REF
IN
REF
OUT
(–) IN LO
5V RET
2
DISP EN
(+) IN HI
22µF
10V
+
6
3
+
–
DMS-20PC-0
11
0.150V
1
1.5 Amp (Load Current)
5Vdc
7
8
+5V SUP
5V RET
DP1
(+) IN HI
REF OUT
REF IN
2
DISP EN
0.1W
RShunt
Load
(3.3 )
12
(–) IN LO
W
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
Connections
for ±2V, ±20V
and ±200V models
Connections
for ±200mV
models
COM
17.4k, 1%
2k
24.3k, 1%
3
12
DMS-20PC-1
8
NC
200
+5V IN
1
1
1
1
www.murata-ps.com/support
DMS-20PC Series
3½ Digit, LED Display, Low-Cost, Subminiature
Digital Panel Voltmeters
MPM_DMS_20PC.F01 Page 5 of 6
APPLICATIONS
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-20PC-X-XX
FRONT VIEW
DP1 DP2 DP3
PIN #1
IDENTIFIER
+5V SUPPLY
DISPLAY ENABLE
5V RETURN
DP3
DP2
DP1
1
2
3
4
5
6
(–) INPUT LO
(+) INPUT HI
ANALOG COMMON
DISPLAY TEST/HOLD
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.
0.475 (12.07)
0.040
(1.02)
1.30
(33.0)
1.38
(35.1)
0.88
(22.4)
0.170
(4.32)
0.150
(3.81)
PIN 1
0.125 (3.175) DIAMETER
(USE ONLY WHEN
PC BOARD MOUNTING)
CALIBRATION POTENTIOMETER HOLE LOCATION
BEZEL
PANEL
#2-56 INSERT
0.156 (3.96) DEEP
FRONT VIEW 1.280
(32.51)
0.187
(4.75)
1.826 (46.38)
0.838
(21.29)
1.626 (41.30)
1.07
(27.18)
INTERNAL CORNER RADII:
0.032 (0.81) MAX.
0.093 (2.362) DIA
(4 REQUIRED)
0.116 (2.95)
1.336 (33.93) 0.145 (3.68)
PANEL CUTOUT
www.murata-ps.com/support
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-20PC Series
3½ Digit, LED Display, Low-Cost, Subminiature
Digital Panel Voltmeters
MPM_DMS_20PC.F01 Page 6 of 6
MECHANICAL SPECIFICATIONS
BEZEL INSTALLATION AND RECOMMENDED DRILL AND PANEL CUTOUT
