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DMR20-10-DCM
2-Wire, Self-Powered,
FEATURES
Self-powered, requires only two connections
Auto-ranging 6 to 75Vdc input range
Installs in round “oiltight” 1.20 inch (30.5mm) cutouts
Reverse polarity protected to –100Vdc
Four-digit LED display with overvoltage indication
Digital replacement for analog panel meters
Screw-style terminal block simplifi es installation
Self-resetting internal fuse for long-term reliability
Provides moisture resistance to IP67/NEMA 6
Supplied with EPDM rubber gasket and plastic hex nut
Panel knockout punches and tooling available
Performance/Functional Specifi cations
Typical at Ta = +25°C, unless otherwise noted
DC Input (TB1)
Input voltage range ➀
Current Consumption
Reverse Polarity Protection
Performance
Sampling Rate
Resolution
Accuracy @ +25°C
HI Range ➁
LO Range ➁
Overrange Indication ➂
Temperature Drift
Mechanical
Dimensions
Display Type
Weight
Case Material
Terminal Block Torque
Wire Size And Type
Wire Insulation Strip Length
Environmental
Operating Temperature
Storage Temperature
Humidity (non-condensing)
+6 to +75Vdc
@Vin = 75.0Vdc: 7mA (max.)
-100Vdc (min.)
2.5 readings/second
0.01Vdc in LO Range;
0.1Vdc in HI Range
±0.2V (typ.), ±0.4V (max.)
±0.03V (typ.), ±0.06V (max.)
See note 3
±0.003V/°C (typ.)
1.50"diameter x 1.08 depth"
(38.1 x 27.4mm)
Four digit, LED, 0.30" high (7.6mm)
0.6 ounces (18 grams)
with nut and gasket
Polycarbonate
2.2 lb·in (0.25 N·m) ±20%
18-22AWG (0.83-0.33mm
solid or stranded
0.25" (6.4mm)
–25 to +60°C
–40 to +75°C
0 to 85%
2
) copper,
Auto-Ranging DC Voltage Monitor
Murata Power Solutions’ new DMR20-10-DCM self-powered, auto-ranging DC voltage
monitors are designed to measure and display the outputs the most popular DC power
systems. Simply connect any 6 to 75V DC power source and these meters are fully operational—no additional components or power sources are required.
Their large, 0.30"/7.6mm, bright LED displays can be easily read from 10 feet away (3
meters). These auto-ranging meters accurately display DC voltages with 0.01V in the LO
Range (below 51V), or 0.1V resolution in the HI Range (above 51 V). A built-in resettable
fuse assures long term reliability. All DMR20-10-DCM’s employ a 13-bit A/D converter
and precision metal-fi lm resistors to achieve outstanding performance over an operating
temperature range of –25 to +60°C.
The DMR20-10-DCM 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 into the panel, and securely fasten
the meter using the supplied hex nut. The supplied hardware is designed to provide protection to IP67/NEMA 6.
Ordering Information
DMR20-10-DCM-R-C 6 to 75Vdc voltage monitor (Red LED)
Tooling
DMR20-1-KP
DMR20-2-KP
DMR20-3-KP
Note: An M30 x 1.5 nylon hex nut and EPDM sealing gasket are supplied with each meter.
The “-C” suffi x denotes RoHS compliance.
1.2" (30.5mm) Round knockout punch
(no keying notch)
1.2" (30.5mm) Round knockout punch
(with four keying notches)
1/8" and 3/16" (3.2 and 4.7mm)
key-notch nibbler tool
➀ Operation and accuracy at inputs above or below these ranges are not specifi ed.
➁ When auto-range operation is enabled via jumper JP1 and Vin is between 6V to 51V, the
displayed resolution is 0.01V (i.e., the unit is in LO Range). When Vin is 51V and above, display
resolution is 0.1V (i.e., the unit is in HI Range). When the unit is in the HI range and Vin drops
below 49V, it will auto-range back to the LO Range.
➂ When Vin is between 75V and 80V, the display will alternate from dim to normal intensity at
approximately one second intervals. When Vin exceeds 80V, display will fl ash on and completely
off at approximately one second intervals. Continuous operation above 80V will permanently
damage the meter and void its warranty.
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For full details go to
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MPM_DMR20-10-DCM.B01 Page 1 of 4
NANO
DMR20-10-DCM
2-Wire, Self-Powered,
TECHNICAL NOTES
IMPORTANT! To ensure safe and reliable operation, DMR20-10-DCM
DC voltage monitors must be installed and serviced by qualifi ed
technical personnel. Contact Murata Power Solutions if there is
!
any doubt regarding installation or operation.
1. Operating Input Range: The unit is shipped with auto-range jumper
JP1 in the open position. With JP1 open, auto-range operation is
disabled and the unit will display input voltages between +6 to +75Vdc
with a fi xed 0.1V resolution. Changes to JP1’s confi guration must only
be made when the unit is off (de-energized). The unit will not recognize
JP1 confi guration changes made with power applied to TB1.
Closing jumper JP1 (see Figure 1) places the unit in the auto-range
mode of operation. With auto-range enabled and Vin between +6V to
+51V, the displayed resolution is 0.01V (i.e., the unit is in LO Range).
When the unit is in LO Range and Vin is increased to +51V, it will autorange to the HI range and display 0.1V resolution. When the unit is in
HI range and Vin drops below +49V, it will auto-range back to the LO
Range and display 0.01V resolution.
Operation below +6Vdc will produce a noticeably dimmer display and
accuracy is not guaranteed. Continuous operation between +75 and
+80Vdc, while not recommended, will not adversely affect the unit. See the
“Performance/Functional Specifi cations” section for more information.
2. Calibration: DMR20-10-DCM voltmeters are factory calibrated; there
are no provisions for calibrating these meters in the fi eld.
3. Panel Installation: All electrical connections to DMR20-10-DCM must
be made after the voltmeter is securely attached to the panel, and with
the input DC input supply source de-energized (off). In high-vibration
environments, adequate strain reliefs must be used on all supply
wiring. See Figure 2 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.
Panel Thickness:
When using both the factory supplied EPDM gasket and hex nut (the
recommended standard installation method), the DMR20-10-DCM 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, and dust and moisture ingress.
Auto-Ranging DC Voltage Monitor
Panel Materials:
Acceptable panel materials include aluminum, mild steels, plastics,
FR-4 pc-board (fi berglass), and many other materials with a fl at 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.
DMR20-10-DCM has passed vibration testing combined with tem-
perature cycling while mounted to the materials noted above, using
the specifi ed tightening torques. If the voltmeter will be mounted to
extremely smooth or slippery surfaces, the user is advised to test the
completed assembly under the environmental conditions expected in
the end application.
4. Input Fusing and Wiring: DMR20-10-DCM voltmeters contain an
internal, self-resettable fuse. However, the supply wires connected to
input terminals TB1’s “+” and “–” terminals 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 specifi c 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 (0.83mm
to 0.33mm
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
DC supply input.
5. Input Polarity: The input terminal block TB1 is polarity sensitive, and
connections to it must be made as shown in the Mechanical Specifi cations section of this data sheet. However, intermittent or continuous
application of reverse-polarity voltages up to –100V will not damage
the meter.
2
) solid or stranded copper wire. The supply wires must be
Figure 1. JP1 confi gured for auto-range operation
2
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MPM_DMR20-10-DCM.B01 Page 2 of 4
MECHANICAL SPECIFICATIONS
NANO
Figure 2. Panel Installation
DMR20-10-DCM
2-Wire, Self-Powered,
Auto-Ranging DC Voltage Monitor
0.062 (1.58)
1.50 (38.1)
DC VOLTS
V
0.100 (2.54)
0.080 (2.03)
0.10 (2.5)
0.98 (24.9)
0.55 (14)
Dimensions are in inches (mm).
1.18 (29.8)
TB1
J1
-+
0.655 (16.64)
Recommended panel cutout
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1.210 (30.73)
Tolerances (unless otherwise specifi ed):
.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
MPM_DMR20-10-DCM.B01 Page 3 of 4
NANO
DMR20-10-DCM
2-Wire, Self-Powered,
NOTES
Auto-Ranging DC Voltage Monitor
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfi eld, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
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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/
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.
MPM_DMR20-10-DCM.B01 Page 4 of 4
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