DMS-20ACV-3-R-C - MURATA MANUFACTURING

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DMS-20ACV Series

480V, Self-Powered, AC Line Monitor

MPM_DMS-20ACV.B02 Page 1 of 4

Murata Power Solutions’ DMS-20ACV-3 is a low-cost, self-powered, 2-wire digital AC voltmeter designed

for monitoring 3-phase, 480Vac primary ac power sources. The DMS-20ACV-3’s unique power-supply

design allows a single model to operate from 350 to 600Vac, at line frequencies of 50 to 60Hz. No user-

supplied external components or auxiliary power sources are needed for full operation. Its large, 0.40 inch

(10.2mm), bright red or green LED display is easily readable under virtually all lighting conditions.

DMS-20ACV-3 AC voltmeters employ a microprocessor driven, half-wave averaging, analog-to-digital

converter to achieve a display resolution of 1Vac over its entire operating range. Also, the unit is per-

manently calibrated at the factory, ensuring stable, long-term accuracy by eliminating issues caused by

user-accessible adjustment potentiometers.

The DMS-20ACV-3 measures only 1.94” wide x 1.27” high (49.3mm x 32.3mm), and has an installed

behind-the-panel depth of less than 1.0” (25.4mm). Panel mounting is greatly simpliﬁ ed by the use of a

bezel assembly that includes a color ﬁ lter and secure metal fasteners.

This easy-to-use AC voltmeter is the ideal digital upgrade for fragile, less accurate, analog panel meters

used in 480Vac power distribution environments. It similarly excels in any new application requiring accu-

rate, high-voltage, AC line monitoring. Simply connect the AC power source to its 2-position terminal block

and the unit is fully operational.

FEATURES

 Self-powered, 2-Wire operation

 350 to 600Vac (50/60Hz) measurement range

 Digital replacement for analog panel meters

 Permanent, tamper-proof calibration

 Half-wave averaging, rms calibrated input

 Large, easy-to-read, bright red or green LED

display

 Flashing display warns of overvoltage conditions

 Reliable screw-style terminal block simpliﬁ es

hookup

 Rugged bezel assembly with secure metal

fasteners

 Small footprint: 1.94W" x 1.27H" (49mm x 32mm)

PRODUCT OVERVIEW

MECHANICAL SPECIFICATIONS

MECHANICAL DIMENSIONS: Inches (mm)

TOLERANCES: 2 PL DEC ±0.02 (±0.51)

3 PL DEC ±0.010 (±0.254)

FRONT VIEW

BACK VIEW

SIDE VIEW

1.930

(49.02)

1.260

(32.00)

0.28

(7.1) 0.64

(16.3)

BTB1

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DMS-20ACV Series

480V, Self-Powered, AC Line Monitor

MPM_DMS-20ACV.B02 Page 2 of 4

TECHNICAL NOTES

IMPORTANT! To ensure safe and reliable operation, DMS-20ACV ac

voltmeters must be installed and serviced by qualiﬁ ed technical

personnel. Contact Murata Power Solutions if there is any doubt

regarding installation and/or operation.

1. Measurement Type: DMS-20ACV series AC voltmeters employ a

precision analog-to-digital converter and a stable voltage reference to

measure and display the average value of sinusoidal AC mains voltages.

Input voltages of 601V and above will cause the display to ﬂ ash on and

off.

2. Calibration: DMS-20ACV voltmeters are digitally calibrated at the fac-

tory; there is no provision for calibrating units in the ﬁ eld.

3. Power Supply Polarity, Fusing, Wiring, and Grounding: DMS-20ACV-3’s

TB1 ac-supply terminals are not polarity sensitive, that is, they have

no “AC LO” or “AC HI” designations. These meters do not include nor

require a connection to earth/chassis ground.

DMS-20ACV-3 AC voltmeters are not internally fused. Terminal block

TB1 is to be used only for powering the voltmeter’s internal circuitry; it

must not be used to supply power to external loads or auxiliary devices.

The supply wires connected to TB1 must be fused with a 0.25A/600V

time delay/time lag fuse, in accordance with applicable regulatory

codes.

All AC-supply wiring must be rated for the voltages and currents they

will conduct and comply with any code or application-mandated

requirements pertaining to the user’s speciﬁ c installation. 600V, UL-

rated wire suitable for the intended application is required.

The recommended AC supply wire size is 16AWG to 22AWG (1.31mm2

to 0.325mm2) stranded copper wire. The supply wires must be properly

stripped and attached to TB1 such that their insulation is not pinched

by the screw terminal. Recommended insulation strip length is 0.25"

(6.4mm). Rated tightening torque for the TB1’s screws is 7 pound-

inches (0.8 N-m).

Performance/Functional Speciﬁ cations

Typical at TA=+ 25°C, 480Vac @ 60Hz, unless otherwise noted

Input Supply Voltage (Vin @ TB1) Min. Typ. Max. Units

AC (rms) Voltage @ 47-63Hz 350 480 600 Volts AC

Performance

Sampling Rate 2 samples/sec

Voltage Accuracy @ 25° C ±2 ±4 Volts

Temperature Drift (0 to 60ºC) 0.05 Volts/°C

Measurement Type Half-wave averaging, rms calibrated for

sinusoidal inputs

Supply Current

@ 50Hz 8 11 mA

@ 60Hz 9 13 mA

Display

Display Type 3 Digit LED

Display Size 0.40 inches (10.16mm) high

Overrange Indication Flashing display for Vin > 600 Volts

Physical/Environmental

Weight 1.0 ounces (28 grams)

Operating Temperature -25 60 °C

Storage Temperature -40 75 °C

Relative Humidity (Non Condensing) 0 85 %

Ordering Information

DMS-20ACV-3-R-C 350 to 600Vac (50/60Hz) Red LED Display

DMS-20ACV-3-G-C 350 to 600Vac (50/60Hz) Green LED Display

*See technical note 3. Figure 1. Wiring Diagram

BACK VIEW

TB1

350-600 Vac

47-63 Hz

Fuse*

0.25A/600V

FRONT V IEW

1.280

(3 2 .5 1 )

0.1 8 7

(4.7 5 )

1.8 2 6 ( 4 6 .3 8 )

RECO E M MN D ED D R L IL A N D

PA N EL C U O TUT D I E MNS O INS

0.838

(2 1 .29)

1.0 7

(2 7 .1 8 )

INTER N AL C OR N ER R AD : I I

0.0 3 2 ( 0.8 1 ) M A X .

0.1 1 6 ( 2.9 5 )

1.6 2 6 ( 4 1 .3 0 )

0.0 9 3 ( 2.362) D I E M A TER ( 4 R EQUIRED)

1.3 3 6 ( 3 3 .9 3 )0.1 4 5 ( 3.6 8 )

(17.5)

0.69

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DMS-20ACV Series

480V, Self-Powered, AC Line Monitor

MPM_DMS-20ACV.B02 Page 3 of 4

PANEL INSTALLATION

BEZEL AND PANEL CUTOUT

All electrical connections to DMS-20ACV must be made after the voltmeter

is securely attached to the panel, and with the input AC supply voltage

de-energized (off). Care must be exercised when attaching the AC supply

wires to terminal block TB1. The installed wire-positions should be such

that minimal forces are applied to TB1 or the voltmeter. In high-vibration

environments, adequate strain reliefs must be used on all supply wiring.

Using Figure 2 as a guide, carefully insert the bezel/color ﬁ lter assembly

into the panel opening. From the rear of the panel, install the four 8mm

plastic standoffs over the bezel’s threaded studs. Install the DMS-20ACV

pc-board assembly and attach and tighten the four #2-56 hex nuts over the

threaded studs. Tighten each hex nut to 15 to 20 ozf-in (0.11 to 0.14 N-m).

Figure 2. Panel Installation

Use only the factory-supplied hardware as the use of substitute hardware

may result in an unsafe installation and/or adversely affect the reliability of

the installation.

The range of panel thicknesses that can be accommodated with the

factory supplied hardware is 0.040 inches (1.0mm) to 0.125 inches

(3.2mm). Panel thicknesses greater than 3.2mm may require additional

user-supplied hardware or modiﬁ cations to achieve an electrically safe and

mechanically secure installation. However, do not use any substitutes for

the 8mm round plastic standoffs supplied with the voltmeter. Please note,

thick panels will alter the readability of the LED display.

SIDE VIEW

Bezel

Gasket Standoff

Nut

DMS-20ACV

AC Voltmeter

Board-Cutout

PANEL

Gasket Standoff

0.315 (8mm)

0.032 (0.8) Thick

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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

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-20ACV Series

480V, Self-Powered, AC Line Monitor

MPM_DMS-20ACV.B02 Page 4 of 4

NOTES