MURATA DMR20-1-ACV

NANO
www.murata-ps.com
DMR20-1-ACV
Self-Powered,
85 to 264Vac, LED Display Line Monitor
FEATURES

Universal 85 to 264Vac measurement range

Self-powered directly from the AC supply

Installs in “oiltight”1.20 inch (30.5mm) round cutouts

Four-digit LED display with overvoltage indication

Reads true-rms value to 0.1V resolution

Knockout punches and tooling available

Digital replacement for analog panel meters

Screw-style terminal block simplifies installation

Self-resetting internal fuse for long-term reliability

Provides moisture resistance to IP67/NEMA 6
Murata Power Solutions’ new DMR20-1-ACV self-powered, AC line-voltage monitors are
designed to measure and display the true-rms voltage of AC power systems. Simply connect any 85 to 264Vac 50/60Hz power source and these meters are fully operational—no
additional components or power sources are required. The unit can also measure distorted
AC power sources including triangle, square, and the quasi-sine output of many DC to AC
power inverters.

Supplied with EPDM rubber gasket and plastic hex nut

UL/CSA approvals pending
Performance/Functional Specifications
85 to 264Vac (47-63 Hz)
@Vin = 250Vac: 30mA (max.)
@Vin = 120Vac: 15mA (max.)
The DMR20-1-ACV is housed in a rugged, round polycarbonate case that provides excellent
protection against moisture, dust, shock and vibration. Panel installation is straightforward:
Using readily available tooling, simply drill and punch a 1.2 inch (30.5mm) diameter hole and
anti-rotation notch, insert the meter and gasket, and securely fasten the meter using the supplied hex nut. The supplied hardware is designed to provide protection to IP67/NEMA 6.
2.5 readings/second
0.1Vdc
±.1V (typ.), ±.2V (max.)
(–25 to +60°C) ±0.05V/°C (max.)
Their large, 0.30"/7.6mm, bright LED displays can be easily read from 10 feet away (3
meters). These meters accurately display ac voltages with 0.1V resolution. A built-in resettable fuse assures long term reliability. All DMR20-1-ACVs employ a 13-bit A/D converter
and precision metal-film resistors to achieve outstanding performance over an operating
temperature range of –25 to +60°C.
Typical at Ta = +25°C, fin = 60Hz
AC Input (TB1)
Voltage Range ➀
Current Consumption
Performance
Sampling Rate
Resolution
Accuracy @ +25°C
Temperature Drift
Mechanical
Dimensions
1.50"diameter x 1.15 depth"
(38.1 x 29.2mm)
Display Type
Four digit, LED, 0.30" high (7.6mm)
Weight
0.8 ounce (23 grams)
Case Material
Polycarbonate
Terminal Block Torque
3.6 in-lbs (0.4 N-m)
Wire Size And Type
18-22AWG (0.83-0.33mm2) copper,
solid or stranded
Wire Insulation Strip Length 0.25" (6.4mm)
Environmental
Operating Temperature
–25 to +60°C
Storage Temperature
–40 to +75°C
Humidity (non-condensing) 0 to 85%
➀ Operation and accuracy at inputs above or below these ranges are not specified.
Ordering Information
DMR20-1-ACV-R-C 85 to 264Vac voltage monitor (Red LED)
Knockout Punches
DMR20-1-KP
1.2" (30.5mm) Round knockout punch
(no keying notch)
DMR20-2-KP
1.2" (30.5mm) Round knockout punch
(with four keying notches)
DMR20-3-KP
1/8" and 3/16" (3.2 and 4.7mm)
key-notch nibbler tool
Note: An M30 x 1.5 nylon hex nut and EPDM sealing gasket are supplied with each
meter. The “-C” suffix denotes RoHS compliance.
For full details go to
www.murata-ps.com/rohs
(pending)
(pending)
www.murata-ps.com/support
MPM_DMR20-1-ACV.A02 Page 1 of 4
NANO
TECHNICAL NOTES
!
IMPORTANT! To ensure safe and reliable operation, DMR20-1-ACV
AC voltage monitors must be installed and serviced by qualified
technical personnel. Contact Murata Power Solutions if there is
any doubt regarding installation or operation.
1. Measurement Type: DMR20-1-ACV series AC voltmeters employ a
precision true-rms signal conditioning IC, a 13-bit analog-to-digital
converter, and a stable voltage reference to measure and display 85 to
264Vac 50/60Hz AC supplies. DMR20-1-ACV voltmeters can be powered from—and accurately measure—AC supplies with sine, triangle,
square, and quasi-sine waveforms. High-frequency harmonic components up to 65kHz will be measured with minimal additional error.
2. Calibration: DMR20-1-ACV voltmeters are factory calibrated; there are
no provisions for calibrating these meters in the field.
3. Operating Range: As the AC input voltage is lowered to 95.0Vac (50 or
60Hz) or below, the DMR20-1-ACV’s display will begin to dim slightly,
but it will remain accurate down to its 85Vac rating. Input voltages
above 265Vac will cause the display to flash on and off at approximately one-second intervals.
4. Panel Installation: All electrical connections to DMR20-1-ACV must
be made after the voltmeter is securely attached to the panel, and with
the input AC supply de-energized (off). In high-vibration environments,
adequate strain reliefs must be used on all supply wiring. See Figure 1
for typical panel mounting details.
Tightening Torque:
The recommended tightening torque for the M30 x 1.5 plastic hex nut
is 10 to 17 in-lbs (1.3 to 1.9 N-m). If a torque wrench is not available,
this recommended range can be approximated by hand tightening the
hex nut SLOWLY until it just bottoms out against the panel’s rear surface. From this bottomed-out reference position, using a suitable tool,
tightening the hex nut ¼ turn clockwise will produce approximately 10
in-lbs (1.3 N-m) of torque; tightening it 3/8 turn clockwise will produce
approximately 17 in-lbs (1.9 N-m).
Check to make sure the housing’s anti-rotation key is aligned with the
notches on both the panel and the gasket before tightening the hex
nut. Over tightening the hex nut will distort the rubber gasket and may
damage the threads on both the nut and the housing, thereby compromising the installation’s mechanical integrity and its ability to protect
against environmental effects.
DMR20-1-ACV
Self-Powered,
85 to 264Vac, LED Display Line Monitor
Panel Materials:
Acceptable panel materials include aluminum, mild steels, plastics,
FR-4 pc-board (fiberglass), and many other materials with a flat matte
surface on both sides of the cutout. The DMR-20-x-KP tools can be
used with most panel materials except for stainless steel or other
hardened metals.
DMR20-1-ACV has passed vibration testing combined with temperature
cycling while mounted to the materials noted above, using the specified tightening torques. If the voltmeter will be mounted to extremely
smooth, slippery surfaces, the user is advised to test the completed
assembly under the environmental conditions encountered in the end
application.
5. AC Input Fusing and Wiring: DMR20-1-ACV voltmeters contain an
internal, self-resettable fuse. However, the supply wires connected to
input terminals TB1-A and TB1-B must be fused with an external, user
supplied, 0.25A/300V time delay/time lag fuse, in accordance with
applicable regulatory codes.
All 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 specific installation. 300V, UL-rated
hook-up wire suitable for the intended application is required. TB1 is to
be used only for powering the meter’s internal circuitry; it must not be
used to supply power to external loads.
The recommended TB1 supply wire size is 18AWG to 22AWG (0.83mm2
to 0.33mm2) solid or 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). When using stranded wire, verify that there are no loose
or stray strands that could potentially cause a short circuit across the
AC supply input.
6. AC Input Polarity and Grounding: The AC supply inputs TB1-A and
TB1-B terminals are not polarity sensitive, that is, neither terminal is
designated as “AC LO” or “AC HI.” DMR20-1-ACV voltmeters do not
include, nor require, a connection to earth/chassis ground.
Panel Thickness:
When using both the factory supplied EPDM gasket and hex nut (the
recommended standard installation method), the DMR20-1-ACV can be
mounted in panels ranging from 0.032" to 0.250" (0.8 to 6.4mm) thick.
When the gasket is not used, the panel thickness range is 0.075" to
0.325" (1.9 to 8.3mm). However, using the factory supplied hardware
and tightening torque recommendations results in optimal resistance to
vibration, dust, and moisture ingress.
Figure 1. Panel Installation
www.murata-ps.com/support
MPM_DMR20-1-ACV.A02 Page 2 of 4
DMR20-1-ACV
NANO
Self-Powered,
85 to 264Vac, LED Display Line Monitor
MECHANICAL SPECIFICATIONS
1.08 (27.4)
0.55 (14)
0.080 (2.03)
1.50 (38.1)
1.18 (29.8)
0.10 (2.5)
TRUE RMS
0.655 (16.64)
AC VOLTS
V
A B
TB1
Dimensions are in inches (mm).
0.100 (2.54)
0.062 (1.58)
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.51)
.XXX ± 0.010 (0.254)
Angles ± 2˚
Components are shown for reference only.
3D models are available at www.murata-ps.com/en/3d/meters.html
1.210 (30.73)
Recommended panel cutout
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MPM_DMR20-1-ACV.A02 Page 3 of 4
DMR20-1-ACV
NANO
OSCILLOGRAMS
Self-Powered,
85 to 264Vac, LED Display Line Monitor
The graphs below show typical DMR20-1-ACV readings when the unit is powered from six common ac-voltage waveforms.
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
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. Specifications are subject to change without
notice.
© 2013 Murata Power Solutions, Inc.
www.murata-ps.com/support
MPM_DMR20-1-ACV.A02 Page 4 of 4