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DMS-30PC Series
3½ Digit, LED Display Low-Power,
Miniature Digital Panel Voltmeters
FEATURES
■
■
■
■
Large (0.56"/14.2mm) LED display
8 LED colors
Low-power LED’s optional
Epoxy-encapsulated, 12-pin DIP with built-in color
filter and bezel
Miniature size:
2.17" x 0.92" x 0.56"(55mm x 23mm x 14mm)
Panel or pc-board mountable
4 differential input voltage ranges
Auto-calibration, ±1 count accuracy
User-selectable decimal point placement
Single +5V supply (60mW for low-power models)
0 to +60°C temperature range
Numerous "plug-on" application boards
Low cost
The DMS-30PC Series is a broad line of self-contained, fully operational, 3½ digit volt-
meters with large, easy-to-read LED displays. The 0.56"(14.2mm) high LED's are available
in a wide variety of colors including red, orange, amber, yellow, green, aqua, blue-green, and
super-blue. A high-intensity version of the red display is optional, as are low-power versions
of the red, orange, and green displays.
The small size (2.17" x 0.92" x 0.56") of DMS-30PC meters is achieved by integrating
their display, display drivers, reference circuit, and A/D converter into in a single, epoxy-
encapsulated assembly. The device's 12-pin, component-like, DIP package is both vibration
and moisture proof. Each package incorporates a built-in color filter and bezel and is easily
mounted in either panels or pc cards.
These meters are available in four differential input voltage ranges (±200mV, ±2V, ±20V
and ±200V). Input impedance is 1,000 megohms for the ±200mV and ±2V inputs and 1
megohm for the ±20V and ±200V inputs. CMRR for all devices is 86dB, and inputs are
overvoltage protected to ±250V.
Each meter incorporates an extremely stable, double-regulated reference and is fully
calibrated prior to potting. We guarantee outstanding initial accuracy (±1 count) and
excellent stability (±0.15 counts/°C). All models operate from a single +5V supply, and the
low-power models draw as little as 10mA (50mW total power). A DISPLAY TEST function is
standard on each device.
For popular applications (4-to-20mA, rms-to-dc conversion, ac line power, J and K ther-
mocouples, etc.), the DMS-30PC Series includes a complete line of optional "plug-on" appli-
cation boards that conveniently convert your meter into an application-specific instrument.
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SIMPLIFIED SCHEMATIC DIAGRAM
1
+5V SUPPLY
–5V
2
DISPLAY TEST
DC/DC
CONVERTER
V–
» +2.0V
3
5V RETURN
0 Vdc
A/D
CONVERTER
1.23V
REF.
9
+1.23V REFERENCE OUT
1.82k
5
DP 2
+5V
6
DP 1
7
REFERENCE IN
(1) 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.
+5V
V+
R2 (1)
R1
909k
12
(–) INPUT LO
0.01μF
11
(+) INPUT HI
10 ANALOG
COMMON
4
DP 3
DATA
8
REFERENCE OUT
For full details go to
www.murata-ps.com/rohs
Figure 1. DMS-30PC Series simplified schematic
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MPM_DMS_30PC.F05
Page 1 of 6
DMS-30PC Series
Performance/Functional Specifications
Typical at T
A
= +25°C and supply voltage = +5V using the single-ended input
circuit, unless otherwise noted.
Analog Inputs
Full Scale Input Range:
DMS-30PC-0
DMS-30PC-1
DMS-30PC-2
DMS-30PC-3
Input Impedence:
DMS-30PC-0, -1
DMS-30PC-2, -3
Overvoltage Protection
➀
Common Mode Voltage Range
CMRR (dc to 60Hz)
Control Inputs
➁
Decimal Point Placement
(Pins 4-6)
Display Test
(Pin 2)
Performance
Sampling Rate
Accuracy
(3 minute warm-up):
DMS-30PC-0 (Vin = +0.19V)
DMS-30PC-1 (Vin = +1.9V)
DMS-30PC-2 (Vin = +19V)
DMS-30PC-3 (Vin = +190V)
Zero Reading
(Vin = 0 Volts)
Temperature Drift (0 = +60°C)
+1.23V Reference Output
(Pin 9)
➁
Power Supply Requirements
Supply Voltage
Supply Current:
Standard Models
Low-Power Models
Red Display
Green or Orange Display
Display
Display Type and Size
Polarity Indication
Overrange Indication
Physical/Environmental
Operating Temperature
Storage Temperature
Humidity (non-condensing)
Case Material
Weight
0
–40
0
–
–
–
+60
+75
95
°C
°C
%
3½ digit, 0.56"/14.2mm high LED
Autopolarity ("–" for negative Vin)
"–1_ _ _ " for negative inputs
"1_ _ _ " for positive inputs
–
–
+12
+60
+17
+100
mA
mA
–
+150
+225
mA
+4.75
+5.00
+5.25
Volts
–
–
–
–
“–001”
–
+1.20
±1
±1
±2
±2
“000”
±0.2
+1.23
±3
±3
±3
±3
“001”
±0.4
+1.25
Cnts/°C
Volts
A panel-mount retaining clip is supplied with each model.
Counts
Counts
Counts
Counts
2.5 reading per second
Add-On Application Boards:
DMS-EB-C
Multi-purpose (gain/offset, 4-20mA, etc.)
DMS-EB-HTB
High-accuracy temperature probe sensing for
±200mV models
DMS-EB-DC/DC
Provides isolated +5V power
DMS-EB-RMS-C
For true rms measurements of ac voltages
DMS-EB-AC/DC-C
For ac line-powered applications
Tie to pin 3 to activate
Tie to +5V to activate all segments
–
–
–
–
–
100
0.8
–
–
–
1000
1
–
–
86
–
–
±250
±2
–
MΩ
MΩ
Volts
Volts
dB
±200
±2
±20
±200
–
–
–
–
mV
Volts
Volts
Volts
Input Range:
0
= ±200mV
1
= ±2V
2
= ±20V
3
= ±200V
±200V
available on the
following models only:
-BS (Super Blue)
-GS (Standard Green)
-RS (Standard Red)
-RL (Low-Power Red)
-VFS (Blue-Green)
Accessories:
DMS-30-CP
DMS-BZL1-C
DMS-BZL2-C
Min.
Typ.
Max.
Units
3½ Digit, LED Display Low-Power,
Miniature Digital Panel Voltmeters
Ordering Information
DMS-30PC - 1 - R S - C
Add -C for RoHS
LED Color:
AS
= Standard Amber
BS
= Super Blue
GS
= Standard Green
OS
= Standard Orange
QS
= Standard Aqua
RS
= Standard Red
YS
= Standard Yellow
RH
= High-Intensity Red
GL
= Low-Power Green
OL
= Low-Power Orange
RL
= Low-Power Red
VFS
= Blue-Green
Panel cutout punch
DMS-30 bezel assembly
DMS-30 bezel assembly with sealing gasket
TECHNICAL NOTES
1. +1.23V REFERENCE OUTPUT (Pin 9):
This pin is the output
of the meter’s precision +1.23V internal reference, and it is
referenced to ANALOG COMMON (pin 10) which sits at a potential
of approximately +2V. This output should be buffered if used to
drive external loads since sourcing more than 15μA from pin 9 can
affect both the initial accuracy and temperature drift of the meter.
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) or to your
system’s analog ground.
3. REFERENCE OUTPUT (Pin 8) and INPUT (Pin 7):
Pin 8 is a preci-
sion reference actively trimmed at the factory. In normal opera-
tion, pin 8 must be tied to pin 7 to achieve all listed accuracy and
drift specifications.
Polycarbonate
0.75 ounces (21 grams)
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.
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MPM_DMS_30PC.F05
Page 2 of 6
DMS-30PC Series
3½ Digit, LED Display Low-Power,
Miniature Digital Panel Voltmeters
4. DISPLAY TEST (Pin 2):
Connecting pin 2 to +5V SUPPLY (pin 1) will
activate all LED segments, except the decimal points, and the display
will read "1888" regardless of the actual applied input. If a negative
input is applied, DISPLAY TEST will also activate the minus sign. To
protect the LED's, the display should not be left in the "test" mode for
more than 10 seconds.
5. 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 desired 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
DMS-30PC-X-RL
All Others
Applied "0" Voltage Load Current*
+0.05V max.
+0.4V max.
0.7mA max.
6mA max.
APPLICATIONS
DMS-30PC meters are highly versatile devices that can be used in
hundreds of applications. The application circuits chosen for this sec-
tion have historically received many inquiries. Every attempt has been
made to ensure technical accuracy, and all of the following circuits
have been prototyped and tested to ensure functionality. Please keep
in mind, however, that real-world applications are seldom as straight-
forward as the approaches presented here. Most applications have
many more components — and many more connections — than the
illustrations show.
The simplified schematic shown in Figure 1 can be very useful when
debugging a malfunctioning panel meter circuit, particularly if the
user has some knowledge of operational amplifiers (op amps). The
meter's high-impedance input consists of an op amp powered from a
±5Vdc power supply (the –5V is internally generated). Knowing this,
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 resis-
tor. 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).
One of the simplified schematic's noteworthy features is that it
shows internal voltage values. It 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 Configurations:
True single-ended measure-
ments can be made with any DMS-30PC 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). This will ensure that large LED currents will not
flow in the wiring that connects V
IN
to (–) INPUT LO (pin 12). Ground-
loop currents can cause unstable readings.
DMS-30PC-1
8
REF OUT
* The driving gates must be able to sink this much current
(I
OL
) with a logic "0" output.
6. Gain Adjust:
There is a gain-adjust potentiometer on the back of
each meter. It has approximately ±50 counts (±2.5%) 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. The circuit shown in Figure 10 provides ±10% range of
adjustment.
7. Soldering Methods:
All models in the DMS-30PC Series easily
withstand most common wave soldering operations. We recom-
mend, 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
Terminal type
Crimping tool
Wire size
Insulation diameter
Stripping length
Board mounted:
Socket
DATEL P/N 4320-01069-0
DATEL P/N 4400-01032-0
DATEL P/N 39-2099000
22 to 26 AWG
0.062" (1.57mm) maximum
0.100 to 0.125" (2.54 to 3.17mm)
DATEL P/N 4320-01074-0
11
(+) IN HI
+
V
IN
–
12
(–) IN LO
1
+5V SUP
6
DP1
3
5V RET
7
REF IN
85-264Vac
AC to DC Converter
Figure 2.
Single-Ended Input Configuration
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MPM_DMS_30PC.F05
Page 3 of 6
DMS-30PC Series
APPLICATIONS
2. Differential Input Configurations:
Differential measurements can
be made with all DMS-30PC 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.
DMS-30PC-1
REF OUT
8
R1
1k
3½ Digit, LED Display Low-Power,
Miniature Digital Panel Voltmeters
pin 10 (ANALOG COMMON) or pin 3 (5V RETURN) 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-30PC-1
8
REF OUT
11
(+) IN HI
11
(+) IN HI
+
REF IN
7
DP1
6
12
(–) IN LO
R2
1k
1.5V
CELL
–
12
(–) IN LO
7
REF IN
1
+5V SUP
3
5V RET
6
DP1
1
+5V SUP
3
5V RET
R3
1k
85-264Vac
85-264Vac
AC to DC Converter
AC to DC Converter
Figure 3.
Differential Input Configuration
Figure 5.
Floating Input Measurements
3. Engineering Scaling:
For measuring voltages greater than the full
scale input range of a given meter, the input signal must be attenu-
ated. 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 engineer-
ing scaling.
50kΩ < R1 + R2 < 10MΩ
R2
x V
IN
= Reading
R1 + R2
+
11
(+) IN HI
10
ANA COMM
12
(–) IN LO
1
+5V SUP
+
DMS-30PC-1
8
REF OUT
1.5V
CELL
–
7
REF IN
3
5V RET
6
DP1
85-264Vac
AC to DC Converter
R1
V
IN
R2
11
(+) IN HI
DMS-30PC-1
8
REF OUT
Figure 6.
Floating Input Measurements
(Alternate Configuration)
–
12
(–) IN LO
7
REF IN
1
+5V SUP
3
5V RET
85-264Vac
AC to DC Converter
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-30PC 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:
R
Shunt
= R1 = V
Fsr
/ I
Fsr
Where:
V
Fsr
= Full scale reading (in Volts)
I
Fsr
= Relative full scale current (in Amps)
Figure 4.
Input Attenuation Circuit
4. Floating Signal Source Measurements:
Floating signals can be
measured using the circuits shown in Figures 5 and 6. Connecting
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MPM_DMS_30PC.F05
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DMS-30PC Series
APPLICATIONS
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), V
Fsr
= 1.000 Volts
R
Shunt
= 1.000V/(0.020 – 0.004)A
R
Shunt
= 1.000V/0.016A = 62.5 Ohms
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 R
Shunt
accordingly.
11
(+) IN HI
10
ANA COMM
12
(–) IN LO
9
1.23V
REF
1
5V SUP
3
5V RET
3½ Digit, LED Display Low-Power,
Miniature Digital Panel Voltmeters
and thermal run-away. When using other, higher-power, DMS-30PC
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 finding ever-increasing
usage because analog-style ammeters (moving-vane types) now cost
roughly the same as their digital counterparts. Additionally, analog
ammeters are not nearly as rugged as modern digital panel voltme-
ters. 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. A detailed application note
describing digital dc ammeters is included in DATEL's new Digital
Panel Meter Databook.
1
+5V SUP
DMS-30PC-1
8
REF OUT
DMS-30PC-0
8
REF OUT
4-20mA
85-264Vac
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-30PC-2-RL can be configured
to allow power supply monitoring over the range of 4.5-18Vdc. The
circuit in Figure 8 uses a low-drop-out, three-terminal regulator (LM-
2931Z-5, available from National Semiconductor) to provide regulated
5V power to the meter. The LM-2931 was chosen because it has the
following on-chip protection features: reverse polarity, short circuit
+
R1
+
5Vdc
7
REF IN
–
3
5V RET
6
DP1
7
REF IN
12
(–) IN LO
0.150V
1.5 Amp (Load Current)
0.1W
R
Shunt
Load
(3.3 W)
11
(+) IN HI
R2
–
50k
AC to DC Converter
Figure 7.
4-to-20mA Current Loop Operation
Figure 9.
Basic DC Ammeter Circuit
8. External Gain Adjustment:
Connect REFERENCE OUT
(pin 8) to REFERENCE IN (pin 7) for normal, factory calibrated,
operation. Use the +1.23V REFERENCE OUT (pin 9) for applica-
tions needing external gain adjustment. Figure 10 shows the wiring
configuration for each model. Calibration is performed with a precise,
near-full-scale, input voltage.
11
(+) IN HI
DMS-30PC
OUT
VOLTAGE
CALIBRATOR
COM
3
5V RET
12
(–) IN LO
10
ANA COMM
8
NC
8.45k, 1%
1k
10 to 20 Turns
7
REF IN
9
1.23V REF
LM2931Z-5
IN
OUT
GND
4.5 - 18Vdc
22μF
10V
(+) IN HI
11
1
+5V SUP
DMS-30PC-2-RL
+
–
+
3
5V RET
5
DP2
7
REF
IN
8
REF
OUT
12
(–) IN LO
Connections
for ±2V, ±20V
and ±200V models
1k
10 to 20 Turns
8.45k, 1%
Connections
for ±200mV
models
Figure 10.
External Gain Adjustment
Figure 8.
4.5-18V Power Supply Monitor
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MPM_DMS_30PC.F05
Page 5 of 6
Embedded System
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