www.murata-ps.com
DMU-30DCV Series
Ruggedized DC Voltmeters with Daylight Readable
Auto-Dimming LED Displays
FEATURES
Measure and accurately display dc voltages in harsh
environments
input ranges: ±200mVdc, ±2Vdc, ±20Vdc, and
Four
±200Vdc
Daylight-readable LED display with automatic
brightness adjustment
Moisture & impact resistant package offers
NEMA-4/IP65 protection
Operates from universal 85-264Vac mains, or
110-300Vdc supplies
circuit fully isolated from ac power supply
Input
Murata Power Solutions’ DMU-30DCV series of daylight-readable dc voltmeters
measure and display dc signals as low as ±200mV and as high as ±200V. Their large 0.56”
(14.2mm) high super-bright red LED-display is readable in full sunlight. An auto-dimming
circuit automatically adjusts the display brightness for all viewing conditions.
DMU-30DCV series dc voltmeters are packaged in a rugged, one-piece polycarbonate
plastic housing that features an integrated bezel and gasket assembly. In a typical instal-
lation, the housing is secured to a panel with six metallic threaded inserts, allowing the
unit to meet NEMA-4 / IP65 requirements for moisture and impact resistance in outdoor
applications.
DMU-30DCV series dc voltmeters are available in a choice of four input ranges:
±200mVdc (with 0.1mV resolution); ±2Vdc (0.001V resolution); ±20Vdc (0.01V resolution);
and ±200Vdc (0.1V resolution). The dc signal under measurement is electrically isolated
from the unit’s operating power source.
DMU-30DCV series’ miniature size and rugged package are perfect for industrial and
high-reliability instrumentation, alternative power generators, and any other application
which requires daylight readability and precise monitoring of dc voltages in harsh indoor /
outdoor environments. Simply connect the input signal and an 85-264Vac source of operat-
ing power to the two rear-mounted terminal blocks and the unit is fully operational.
TECHNICAL NOTES
IMPORTANT! To ensure safe and reliable operation, DMU-30DCV dc voltmeters must
be installed and serviced by qualified technical personnel. Contact Murata Power
Solutions if there is any doubt regarding installation and/or operation.
1. Measurement Type:
All DMU-30DCV series dc voltmeters achieve their excellent
performance by employing a precision integrating analog-to-digital converter, metal film
resistor dividers, and a high-stability voltage reference IC. The LED display is updated
approximately 2.5 to 3 times per second. However, while some input filtering is provided,
noisy signals may cause the displayed reading to vary by a few counts.
CAL
BRIGHTNESS
ADJUST
2. Wiring:
All ac supply (TB1) and input signal (TB2) wiring must be adequately rated for
the voltages and currents they will carry, and must comply with any code or application-
mandated requirements pertaining to the user’s specific installation.
3. Power Supply Polarity, Fusing, Wiring and Grounding:
The power supply inputs (TB1-1 and
TB1-2) on DMU-30DCV voltmeters are not polarity sensitive, that is, they have no “AC LO”
or “AC HI” designations. These units do not include or require a connection to earth/chas-
sis ground. Refer to Figure 1 for a typical wiring diagram.
Wires specified in the Functional Specifications section must be used for making connec-
tions to DMU-30DCV series voltmeters. All power-supply and load wiring must be rated
for the supply voltages and currents they will conduct and must comply with any code or
application-mandated requirements pertaining to the user’s specific installation.
DMU-30DCV voltmeters are not internally fused. Terminal block TB1 is to be used only
for powering the power meter’s internal circuitry; it must not be used to supply power
to external loads. The supply wires feeding these power meters must be fused with a
0.5A/250V time delay/time lag fuse, in accordance with applicable regulatory codes.
Wire insulation must be stripped to within ±10% of the stated dimensions, and wires
should be inserted into TB1 such that their insulation is not pinched by the screw terminal.
1
TB1
2
1
+
2
TB2
–
REAR VIEW
85-264Vac
Power Source
Input Signal
Figure 1. DMU-30DCV wiring diagram
For full details go to
www.murata-ps.com/rohs
www.murata-ps.com/support
MPM_DMU_30DCV.B01
Page 1 of 3
DMU-30DCV Series
Ruggedized DC Voltmeters with Daylight Readable
Auto-Dimming LED Displays
TECHNICAL NOTES (continued)
4. Calibration:
Periodic recalibration of DMU-30DCV voltmeters is not required
under normal indoor operating environments. However, operation in environ-
ments subject to vibration and/or extreme temperature variations should
have their accuracy verified on a yearly basis. If recalibration is necessary,
it should only be performed by qualified technical personnel. Calibration is
performed with potentially lethal voltages applied to the DMU-30DCV and its
associated wiring. A plastic, fully-insulated adjusting tool must be used to
access the recessed calibration potentiometer located on the back of the unit
(see Mechanical Specifications). Contact Murata Power Solutions if additional
information is required regarding calibration, setup, or any other technical
issue pertaining to DMU-30DCV dc voltmeters.
5. Minimum-Intensity Adjustment Potentiometer:
Users can adjust the
DMU-30DCV’s minimum LED display brightness to suit their indoor viewing
requirements by adjusting the ¾-turn, rear-mounted intensity adjustment
potentiometer. Please note, this potentiometer will have minimal impact on
display brightness in high ambient light environments.
The intensity adjustment potentiometer is factory preset to its mid-point po-
sition. As viewed from the rear of the meter, and with the model number label
facing up, turning the potentiometer clockwise increases the LED display’s
intensity. See the Mechanical Specifications section for potentiometer loca-
tions.
6. Operation with Power Supplies Lower than 85Vac:
In indoor applications
where daylight readability (i.e., maximum display brightness) is not required,
DMU-30DCV meters will meet their specified accuracy with ac supply volt-
ages (TB1) well below 85Vac. While performance is not guaranteed, DMU-
30DCV voltmeters remain easily readable and accurate with ac supplies as
low as 20Vac.
7. Panel Installation:
All electrical connections to DMU-30DCV must be made
after the meter is securely attached to the panel and with all input and
supply voltages de-energized (off). Care must be exercised when attach-
ing conductors to terminal blocks TB1 and TB2. The installed wire-positions
should be such that minimal forces are applied to the terminal blocks or the
voltmeter. In high-vibration environments, adequate strain reliefs must be
used on all input and supply wiring.
To ensure a secure and moisture/vibration resistant installation, use only
the supplied hardware. Following the four-step sequence shown—being
careful not to apply excessive force or twisting motions—insert the voltmeter
into the panel opening. Tighten all six M3 metric screws to 3 inch-pounds
(0.34Nm). See the Mechanical Specifications section for panel cutout, drill
dimensions, and panel installation information.
Performance/Functional Specifications
Typical at T
A
= +25°C, unless otherwise noted.
Input (TB2)
Full Scale Input Range:
DMU-30DCV-0-DR-C
DMU-30DCV-1-DR-C
DMU-30DCV-2-DR-C
DMU-30DCV-3-DR-C
Performance
Sampling Rate
Accuracy
Zero Reading
(within 30 sec.)
Temperature Drift
(0 to +60°C)
Breakdown Voltage
(TB1 to TB2)
Supply Voltage (TB1)
DMU-30DCV
Supply Current (TB1)
DMU-30DCV
(total darkness)
DMU-30DCV
(full sunlight)
Terminal Block Wiring (TB1 & TB2)
Wire Size
Insulation Strip Length
Screw Tightening Torque
Rated Voltage
Display
Display Type and Size
Decimal Point
Overrange Indication
Physical/Environmental
Operating Temperature
Storage Temperature
Humidity (non-condensing)
Dimensions
Weight
–25
–40
0
–
–
–
+60
+75
85
°C
°C
%
Daylight readable, auto-dimming,
3½ digit, 0.56"/14.2mm high red LED
Fixed, model dependent
"1_ _ _"
16-22 AWG, Solid or stranded
0.250 inches (6.35)
2.2 lb·in (0.25 N·m) ±20%
300Vac
–
–
4
40
6
50
mA/47-
63Hz
mA/47-
63Hz
85
–
264
Vac/47-
63Hz
“–001”
–
2000
2.5 readings per second
±0.4%FS ±2 counts
“000”
±0.2
–
“001”
±0.4
–
Cnts
Cnts/°C
Vdc
0
0
0
0
–
–
–
–
199.9
1.999
19.99
199.9
mVdc
Vdc
Vdc
Vdc
Min.
Typ.
Max.
Units
See mechanical specifications
1.3 ounces (36 grams) nominal
Ordering Information
Model
DMU-30DCV-0-DR-C
DMU-30DCV-1-DR-C
DMU-30DCV-2-DR-C
DMU-30DCV-3-DR-C
Input Range
0 to ±199.9mVdc
0 to ±1.999Vdc
0 to ±19.99Vdc
0 to ±199.9Vdc
➀
Display reading is set to “1888”. Specified power supply currents are steady state; larger
surge currents can occur at initial application of ac power. Power supply input (TB1) set to
120Vac/60 Hz.
See
www.murata-ps.com/dpm-availability
for model-specific availability.
www.murata-ps.com/support
MPM_DMU_30DCV.B01
Page 2 of 3
DMU-30DCV Series
Ruggedized DC Voltmeters with Daylight Readable
Auto-Dimming LED Displays
Mechanical Dimensions: Inches (mm)
Tolerances: 2 PL DEC ±0.02 (±0.51)
3 PL DEC ±0.010 (±0.254)
2.85
(72.39)
1.5
(38.1)
M3 INSERT
0.10 (2.54) DEPTH
1.60
(40.64)
CAL
BRIGHTNESS
ADJUST
1.97
(50.0)
0.26
(6.6)
1
TB1
2
1
2
TB2
FRONT VIEW
PWR
SUPPLY
INPUT
REAR VIEW
+ VIN –
SIGNAL
INPUT
RECOMMENDED DRILL AND PANEL CUTOUT
2.118
(53.8)
0.136 (3.45) DIA
(6 REQUIRED)
Note:
The supplied M3 screws
and washers will accommodate
panel thicknesses from 0.060 to
0.090 inches (1.52 to 2.28 mm).
Tighten screws to 3.5–4.5 in-lbs
(0.4–0.5 Nm).
1.30
(33.02)
PANEL CUTOUT
0.878
(22.3)
1.26
(32.00)
2.52
(64.00)
INTERNAL CORNER RADII
0.032 (0.81) MAX.
PANEL INSTALLATION
Step 1.
Step 2.
Step 3.
Step 4.
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, 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/
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.
© 2015 Murata Power Solutions, Inc.
www.murata-ps.com/support
MPM_DMU_30DCV.B01
Page 3 of 3
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