DMS-40PC-2-RS-C - MURATA POWER SOLUTIONS

(+) INPUT HI

(–) INPUT LO

ANALOG

COMMON

DP4

REFERENCE IN/OUT

+5V SUPPLY

DP 1

DP 2

DP 3

DC/DC

CONVERTER

5V RETURN

+5V

–5V

+5V

2.5V

REF.

DATA

V+

V–

A/D

CONVERTER

0 Vdc

0.01µF

DISPLAY HOLD

DISPLAY TEST

R2 is not used on ±2V (-1) models.

R2 = 101k on ±20V (-2) models and 9.2k on ±200V (-3) models.

909k

www.murata-ps.com

www.murata-ps.com/support

For full details go to

www.murata-ps.com/rohs

DMS-40PC Series

4½ Digit, LED Display Digital Panel Voltmeters

MPM_DMS-40PC.D03 Page 1 of 6

DMS-40PC Series, 4½ Digit, LED Display, Miniature DPM’s are fully self-contained,

component-like, plug-in meters that provide scientiﬁ c-grade accuracy (typically ±2 counts

or ±0.005% of full scale) and outstanding reliability at a very affordable price.

Within its miniature (2.17” x 0.92” x 0.56”), epoxy-encapsulated package, each meter

contains a precision reference circuit; a high-resolution, autozeroing, factory-calibrated

A/D converter; and a large (0.52”/13.2mm), easy-to-read, LED display. LED’s are available

in red, yellow and green colors. Red LED’s are also offered in high-intensity or low-power

versions.

The versatile design of the DMS-40PC Series assures trouble-free installation and

long-term operation. Differential input voltage ranges include ±2V, ±20V and ±200V. Input

impedance is a minimum 800kΩ. Non-inverting inputs are overvoltage protected to ±250V,

and CMRR is typically 86dB (dc to 60Hz).

The DMS-40PC's epoxy-encapsulated package has an integral bezel and color ﬁ lter.

The moisture and vibration-proof package is extremely rugged and well suited for harsh

environments and extended temperatures. Devices are fully speciﬁ ed for

0 to +50°C operation.

All models operate from a single +5V supply and typically consume 500mW. Low-

power models, whose display is just as bright as standard models, typically consume

175mW. DISPLAY TEST and HOLD functions are standard on each meter, and a complete set

of BCD outputs are optional for sending data to CPU's or remote displays.

FEATURES

 Precision, autozeroing, factory-calibrated A/D converter

 Scientiﬁ c-grade accuracy, ±2 counts

 Miniature size: 2.17" x 0.92" x 0.56"

55mm x 23mm x 14mm

 Large (0.52"/13.2mm) LED display

 Choice of red, green or yellow colors

 High-intensity or low-power red LED's optional

 Single +5V supply (175mW for low-power models)

 Epoxy-encapsulated, 12-pin DIP with built-in color ﬁ lter

and bezel

 3 differential input voltage ranges

 DISPLAY HOLD and TEST functions

 Optional BCD data outputs for CPU interface

 0 to +50°C temperature range

Performance/Functional Speciﬁ cations

Typical at TA = +25°C and supply voltage = +5V using the single-ended 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 See Technical Notes.

➂ BCD outputs are optional and must be speciﬁ ed in the part number.

See Ordering Information.

➃ Includes high-intensity and BCD-output models.

1. ANALOG COMMON (Pin 10): This pin is an internal, low-noise

ground for the DMS-40PC. It is internally connected to pin 3

(5V RETURN). Do not connect pin 10 to either pin 3 or your system

ground as this will create a ground loop and possibly result in errone-

ous readings.

2. REFERENCE INPUT/OUTPUT (Pin 7): This pin accesses the meter’s

internal reference and is used during the factory calibration proce-

dure. Pin 7 should be left open in most common applications. It can

be used in certain “ratiometric” applications in which it is desirable

for the meter’s reference to track an external reference. See Ap Note

DMS-AN3 at http://www.murata-ps.com/data/meters/dms-an3.pdf.

3. DISPLAY TEST (Pin 2): Connecting pin 2 to ground (pin 3, 5V

RETURN) will activate all LED segments, and the display will read

“–18888” regardless of the actual applied input. To reduce self-

heating, the display should not be left in the “test” mode for more

than 10 seconds. This pin should be left open if unused.

Analog Inputs Min. Typ. Max. Units

Full Scale Input Range:

DMS-40PC-1 – ±2 – Volts

DMS-40PC-2 – ±20 – Volts

DMS-40PC-3 – ±200 – Volts

Input Impedence: –

DMS-40PC-1 100 1000 – MΩ

DMS-40PC-2, -3 0.8 1 – MΩ

Overvoltage Protection ➀– – ±250 Volts

Common Mode Voltage Range – – ±2 Volts

CMRR (dc to 60Hz) – 86 – dB

Control Inputs ➁

Decimal Pt. Placement (Pins 4-6, 8) Tie to pin 3 to activate

Display Test (Pin 2) Tie to pin 3 to activate all segments

Display Hold (Pin 9) Tie to pin 3 to hold last reading

BCD Outputs ➂

Logic Levels (1 LSTTL load max.):

Logic “1” +2.4 – – Volts

Logic “2” – +0.4 +0.8 Volts

Performance

Sampling Rate 2.5 reading per second

Accuracy (3 minute warm-up):

DMS-40PC-1 (Vin = +1.9V) – ±2 ±3 Counts

DMS-40PC-2 (Vin = +19V) – ±3 ±4 Counts

DMS-40PC-3 (Vin = +190V) – ±3 ±4 Counts

Zero Reading (Vin = 0 Volts) “–001” “000” “001”

Temperature Drift (0 = +50°C)

DMS-40PC-1 – ±0.4 ±1 Cnts/°C

DMS-40PC-2, -3 – ±0.4 ±1.5 Cnts/°C

Power Supply Requirements

Supply Voltage +4.75 +5.00 +5.25 Volts

Supply Current:

Standard Models ➃– +100 +140 mA

Low-Power Models – +35 +50 mA

Display

Display Type and Size 4½ digit, 0.52"/13.2mm high LED

Polarity Indication Autopolarity ("–" for negative Vin)

Overrange Indication "–0000" (ﬂ ashing) for negative Vin

"0000" (ﬂ ashing) for positive Vin

Physical/Environmental

Operating Temperature 0 – +50 °C

Storage Temperature –20 – +75 °C

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.

BCD Output Models:

BCD outputs are only available on the following red meters.

DMS-40PC-1-RS-BCD-C for ±2V input range

DMS-40PC-2-RS-BCD-C for ±20V input range

DMS-40PC-3-RS-BCD-C for ±200V input range

DMS-40PC-1-RL-BCD-C for ±2V input range

DMS-40PC-2-RL-BCD-C for ±20V input range

DMS-40PC-3-RL-BCD-C for ±200V input range

DMS-40PC - 1 - R S - C

LED Color:

GS = Standard Green

RH = High-Intensity Red

RL = Low-Power Red

RS = Standard Red

YS = Standard Yellow

Input Range:

1 = ±2V

2 = ±20V

3 = ±200V

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

Ordering Information

RoHS

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-40PC Series

4½ Digit, LED Display Digital Panel Voltmeters

MPM_DMS-40PC.D03 Page 2 of 6

TECHNICAL NOTES

* The DMS-40PC-3-R L-C is

To Be Discontinued. Last

time buy date is 3/31/2019.

Please click here to view the

Discontinuance Notice.

To Be Discontinued *

* Last Time Buy date is 3/31/2019. Please click here to view the Discontinuance Notification.

show up as unstable display readings. When an input signal, assumed to

be exactly zero volts, has a 1mV (0.001V) ground-loop induced offset, it

is displayed as “0010” on a ±2V input-range meter! See Ap Note DMS-

AN2 at http://www.murata-ps.com/data/meters/dms-an2.pdf describing

power supply wiring and ground loop avoidance techniques.

The DMS-40PC’s simpliﬁ ed schematic, shown in Figure 1, can be very

useful when debugging a malfunctioning circuit, especially if the user

has some knowledge of operational ampliﬁ ers (op amps). The meter’s

high-impedance input consists of an op amp powered from a ±5Vdc

power supply (the –5V is internally generated). Figure 1 shows that input

signals applied to (–) INPUT LO and (+) INPUT HI must to be kept within

the ±5V power-supply rails. Also note that only pin 11 has a current-

limiting 909kΩ series resistor. High input voltages that have a common

ground connection 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 simpliﬁ ed schematic’s more noteworthy features is that it

shows some DMS-40PC internal voltage values and also 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

using digital multimeters to perform system-level measurements. The

multimeter’s negative lead (usually the black one) must always be con-

nected to pin 3 (5V RETURN). This is the only way accurate readings can

be made, particularly if the meter is conﬁ gured for a differential input and

concerns arise regarding common-mode voltages.

1. Single-Ended Input Conﬁ gurations: The DMS-40PC can measure

single-ended signals with either positive or negative polarities. True

single-ended inputs always have one of their two terminals at the

same potential as the DMS-40PC’s 5V RETURN (pin 3). Single-ended

inputs are usually derived from power supplies that have a common

ground with the meter’s +5V supply. Figure 2 shows the recom-

mended connections to be used with this type of input. Pin 12, (–)

INPUT LO, is shown directly tied to ground. This connection to ground

must be a separate wire or pc-board trace originating at VIN’s negative

terminal. This hook-up will normally eliminate display instabilities and

errors caused by ground-loop currents which can occur if

(–) INPUT LO is tied to ground at, or near, pin 3.

Hard wiring is preferable, however, you can exercise dynamic control

over the location of the decimal point by employing drive circuits that

are capable of sinking a minimum of 20mA at voltages less than +0.4

Volts.

6. Gain Adjust: There is a gain-adjust potentiometer on the back of

each meter. It has approximately ±150 counts of adjustment range.

Since these meters 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 adjust-

ments are most effective when performed with higher level input

signals.

7. Soldering Methods: All models in the DMS-40PC 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:

DMS-40PC Series meters are high-precision versatile devices that

can be used in many applications requiring a 0 to 19,999 count digital

display. The application circuits chosen for this section are ones that

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 straightforward as

the approaches presented here.

All inputs applied to DMS-40PC meters must be steady, dc values,

otherwise the input itself may cause display instabilities. Due to their 4½

digit resolution, DMS-40PC meters must be wired with greater care than

their 3½ digit counterparts. Correct power-supply and input-signal wiring

— an absolute must! — helps eliminate ground-loop induced errors that Figure 2. Single-Ended Input Conﬁ guration

4. DISPLAY HOLD (Pin 9): For normal operation, this pin should be left

open. To hold the meter’s last reading and display it continuously, tie

pin 9 to ground (pin 3, 5V RETURN).

5. 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 pin 4,

5, 6 or 8 to pin 3 (5V RETURN). Unused decimal point location pins

should be left open.

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

+5V SUP

(–) IN LO

5V RET

120 VAC

(+) IN HI

DP1

–

AC to DC Converter

DMS-40PC-1-GS

www.murata-ps.com/support

DMS-40PC Series

4½ Digit, LED Display Digital Panel Voltmeters

MPM_DMS-40PC.D03 Page 3 of 6

APPLICATIONS

When using other, higher-power, DMS-40PC models in combina-

tion with three-terminal regulators, be sure to consult the regulator

manufacturer’s data sheet to ensure the device is being utilized safely

and correctly.

Figure 4. 4.5-18V Power Supply Monitor

4. Floating Signal Source Measurements: A ﬂ oating input is a signal

that, before it is applied to the DMS-40PC’s inputs, has no galvanic

connection (direct current path) to the meter or the meter’s power

supply. The circuit shown in Figure 5 illustrates the necessary con-

nections for measuring ﬂ oating inputs. The 1.5V battery represents a

true ﬂ oating input signal since it initially has no connection whatso-

ever in common with the meter. Real-world ﬂ oating inputs typically

originate from power supplies which are transformer isolated from

the DMS-40PC’s +5V supply.

The connection of pin 12 ((–) INPUT LO) to pin 10 (ANALOG COMMON)

is required in order to provide a bias return for the meter’s input

ampliﬁ er. This is because neither pin 11 nor pin 12 are tied to any

reference voltage inside the DMS-40PC (see Figure 1). These connec-

tions are not made internally in order to give the meter the ability to

make differential measurements as described in a previous section.

Figure 5. Floating Input Measurements

3. Power Supply Monitoring: One of the most widely used digital panel

voltmeter applications is monitoring the output voltage of a system

power supply — often the same supply that also powers the meter.

The low-power, red LED DMS-40PC-2-RL, with its excellent 0.001Vdc

resolution, can be conﬁ gured to monitor power supplies with outputs

in the range of 4.5-18Vdc. The circuit in Figure 4 uses a low-drop-

out, three-terminal regulator (LM-2931T-5, in a T0-220 package,

available from National Semiconductor) to provide regulated 5V

power to the meter.

The LM-2931 was chosen because it has the following on-chip pro-

tection features: reverse polarity, short circuit and thermal runaway.

The DMS-40PC-3-RL can monitor voltages up to ±200Vdc, provided

a separate +5V power source is used since many three-terminal

regulators cannot operate with supply voltages greater than 24V. Red,

low-power LED models, with their very low self-heating, are recom-

mended for applications in which low calibration drift is desirable.

Figure 3. Differential Input Conﬁ guration

2. Differential Input Conﬁ gurations: Differential inputs can also be

measured with DMS-40PC meters as shown in the circuit of Figure

3. Differential inputs must also originate from power supplies that

have a common ground with the meter’s 5V RETURN (pin 3). However,

differential inputs usually have both terminals above and/or below

5V RETURN. Figure 3, though not necessarily a typical real-world

application, does serve the purpose of illustrating the concept of a

differential signal.

The voltages developed across R1, R2 and R3 are equal to each other

and measure approximately +1.6666Vdc or 1/3 of the +5V power

source. More importantly, while the signal across R3 is single-ended,

both ends of R1 and R2 are well above ground and are described

here as being differential. Please note that while the DMS-40PC can

measure the voltages across either R2 or R3, it cannot measure

the +1.6666 volts across R1! The voltage at the lower end of R1 is

approximately 3.333V and this exceeds the common mode voltage

limit of ±2V.

+5V SUP

(–) IN LO

5V RET

120 VAC

(+) IN HI

DP1

AC to DC Converter

DMS-40PC-1-GS

+5V SUP 5V RET

120 VAC

DP1

AC to DC Converter

DMS-40PC-1-GS

(–) IN LO

(+) IN HI

1.5V

CELL

–

ANA COMM

DMS-40PC-2-RL

–

4.5 - 18Vdc

LM2931T-5

GND

IN OUT

+5V SUP

5V RET

DP2

(+) IN HI

(–) IN LO

22µF

10V

www.murata-ps.com/support

DMS-40PC Series

4½ Digit, LED Display Digital Panel Voltmeters

MPM_DMS-40PC.D03 Page 4 of 6

APPLICATIONS

5. Engineering Scaling and Input Attenuation: In many applications,

the input signal must be scaled, or divided down, before being applied

to the DMS-40PC. In some situations, the input signal exceeds the

full-scale range of the meter, and in other applications, a direct

one-to-one relation does not exist between the input voltage and

the desired display reading. For an example of the second situation,

assume an input voltage of 1.0Vdc is required to display a reading of

“7500” when applied to a ±2V input meter. An input divider circuit,

constructed with two series resistors with an output-to-input ratio of

0.75, will scale the 1.0V signal down to 0.75V.

Engineering scaling and input attenuation are discussed in Ap Note

DMS-AN4 at http://www.murata-ps.com/data/meters/dms-an4.pdf.

Compensating for inputs which have a zero offset is also discussed.

6. BCD Outputs (DMS-40PC-X-RS and -RL-BCD Models Only):

Models with a “-BCD” sufﬁ x have 12 extra output pins, labeled

A through L (6 per side), that provide the following information: mul-

tiplexed serial BCD data, digit drive, and polarity indication. The data

present on pins A - L simultaneously drives the meter’s internal LED

display. All functions on pins A - L are 5V CMOS compatible, however,

they are only rated to drive one, 74LS series, TTL load. CMOS logic

IC’s, for example 74HC or 74HCT series devices, should be used when

more fan-out capability is required.

As the timing diagram in Figure 5 indicates, 100Hz is the optimum

display scan rate when the BCD outputs are used to drive external

LED displays. Faster scan rates, while permissible, are not necessary.

Slower scanning, however, may result in noticeable “ﬂ ickering” of

the display. Common anode LED’s, combined with a 74LS247 BCD

to seven-segment decoder, is the simplest way of implementing an

external display. A seventy-ﬁ ve to one-hundred Ohm resistor on each

LS247 segment-drive output provides adequate display brightness.

The functions of pins A - L are listed below:

BCD DATA (pins I - L): Four lines are used for BCD (Binary Coded

Decimal) data outputs, representing the numbers 0 - 9. Positive-logic

convention (a high represents a “1”) is used.

DIGIT DRIVE ( pins A - E): These ﬁ ve outputs, when gated with STROBE,

can be used to direct the BCD DATA into external latches. DIGIT DRIVE

outputs may also be connected directly to the bases of NPN transistors

in remote-display conﬁ gurations. The digits are scanned right-to-left, i.e.,

MSD (DIGIT 1 DRIVE) to LSD (DIGIT 5 DRIVE).

BUSY (pin G): This is a status pin that goes high at the start of an ana-

log-to-digital (A/D) conversion cycle and remains high until the conver-

sion ends.

STROBE (pin H): A string of ﬁ ve sequential, active-low, STROBE pulses

are output (after BUSY goes low) indicating the end of a conversion and

the availability of new data. The 5 STROBE pulses occur only once per

conversion, or 2.5 times each second. STROBE can be used to latch the

BCD data (on pins I - L) into external latches. Either edge can be used

since STROBE (~ 5μsec wide) is active only in the center of the cor-

responding DIGIT DRIVE and BCD DATA outputs.

POLARITY (pin F): This pin, which is also used inside the DMS-40PC to

drive the negative-sign segment, indicates whether the last input signal

conversion was positive (POLARITY set high) or negative (POLARITY set

low). POLARITY, unlike BCD DATA, is not multiplexed. For data latching

purposes, POLARITY should be sampled during the STROBE pulse for

digit 1 (most signiﬁ cant digit).

Figure 6. BCD Data Timing Diagram

DIGIT DRIVE 1

(MSD)

Data from

Previous Conversion

DIGIT DRIVE 2

DIGIT DRIVE 3

DIGIT DRIVE 4

DIGIT DRIVE 5

(LSD)

STROBE OUT

BCD DATA

(4 LINES)

Approx. 5µsec

5 Strobes Only Per Conversion

Approx. 2msec

Approx. 8msec

BUSY

MSD

2345

LSD

12345

www.murata-ps.com/support

DMS-40PC Series

4½ Digit, LED Display Digital Panel Voltmeters

MPM_DMS-40PC.D03 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)

#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

MADE IN USA

PANEL

BEZEL

RETAINING CLIP INSTALLATION

PANEL

B1 (LSB)

B8 (MSB)

STROBE

BUSY

MADE IN USADMS-40PC-X-XX

FRONT VIEW

+5V SUPPLY

DISPLAY TEST

5V RETURN

DP3

DP2

DP1

(–) INPUT LO

(+) INPUT HI

ANALOG COMMON

DISPLAY HOLD

DP4

REFERENCE IN/OUT

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.

0.040

(1.02)

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

0.560

(14.22)

(LSD) DIGIT 5

(MSD) DIGIT 1

DIGIT 2

DIGIT 3

DIGIT 4

POLARITY

INSIDE ROW (BCD MODELS ONLY)

(BCD MODELS ONLY)

1.60

(40.6)

0.10

(2.5) TYP.

INSIDE ROW (BCD MODELS ONLY)

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)

DMS- XXXXX-C

PN: 89XXXXX

B506C

LED Brightness letter

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

Murata Power Solutions, Inc.

129 Flanders Road, Westborough, MA 01581 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-40PC Series

4½ Digit, LED Display Digital Panel Voltmeters

MPM_DMS-40PC.D03 Page 6 of 6