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DMS-20PC-FM Series
Self-Powered, 3-Digit LED Display
AC Line Frequency Monitors
MPM_DMS-20PC-FM.H01 Page 1 of 2
Murata Power Solutions’ DMS-20PC-FM Series are the world’s smallest, self-powered,
ac frequency meters. Simply connect the ac line to the two rear input terminals, and the
unit is fully operational with no additional components or auxiliary power required! Two,
50/60Hz models operate over input voltage ranges of 85-140Vac or 170-264Vac. A third,
400Hz model operates over an input voltage range of 85-140Vac. Despite their small size
(1.38" x 0.88" x 1.0"), DMS-20PC-FM meters feature large 0.40"/10.2mm red LEDs that
can be read easily from 15 feet away.
An ultra-stable, quartz-crystal-controlled,
embedded microcomputer provides accuracies
of ±0.1Hz (50/60Hz models) or ±1.0Hz (400Hz
model) over the entire operating temperature
range of –25 to +60°C. Epoxy encapsulated
plastic packages provide excellent protec-
tion against the harsh environments normally
encountered by emergency backup power gen-
erators. DMS-20PC-FM meters are the exact same
size as Murata Power Solutions’ popular AC Line
Voltage Monitors (models DMS-20PC-X-LM).
FEATURES
Self-powered, no external supplies required
3 models: 47.0-99.0Hz (85-140Vac)
47.0-99.0Hz (170-264Vac)
350-450Hz (85-140Vac)
Screw terminals simplify panel mounting
Ideal for emergency power equipment
Small 1.38" x 0.88" x 1.0" packages
Epoxy encapsulated for harsh environments
Large (0.40"/10.2mm) red LED displays
CURRENT
LIMITED
AC SUPPLY
Typical Connection Diagram
Ordering Information
Functional Specifi cations
DMS-20PC-1-FM-C 47-99Hz / 120Vac frequency monitor with threaded standoffs ➁
DMS-20PC-1-FM-F-C 47-99Hz / 120Vac frequency monitor with blade terminals
DMS-20PC-2-FM-C 350-450Hz / 120Vac frequency monitor with threaded standoffs ➁
DMS-20PC-3-FM-C 47-99Hz / 220Vac frequency monitor with threaded standoffs ➁
DMS-20-CP Optional panel cutout punch
DMS-BZL3-C Optional panel mount bezel
DMS-BZL4-C Optional panel mount bezel with sealing gasket
➁ Brass screws (6-32 thread) and a panel-mount retaining clip are supplied with meter.
Input
Freq. Range (Voltage Range): ➀
DMS-20PC-1-FM 47.0-99.0Hz (85-140Vac)
DMS-20PC-2-FM 350-450Hz (85-140Vac)
DMS-20PC-3-FM 47.0-99.0Hz (170-264Vac)
Current Consumption 50mArms (max.)
UL/IEC61010-1 Measurement Category II
Performance
Sampling Rate 4 readings/second
Accuracy (–25 to +60°C):
DMS-20PC-1/3-FM ±0.1Hz
DMS-20PC-2-FM ±1.0Hz
Mechanical
Dimensions 1.38" x 0.88" x 1.00"
Display Type 3 digit, red LED,
0.4"/10.2mm
Weight 1 ounce (28 grams)
Case Material Polycarbonate
6-32 screw torque 6-8 in-lb (0.7 – 0.9N-m)
Environmental
Operating Temperature –25 to +60°C
Storage Temperature –40 to +75°C
Humidity (Non-condensing) 0 to 95%
➀ Operation and accuracy at inputs above or below these
ranges are not specifi ed.
C®US E156931
®
8C48
DMS-20PC-1-FM-F
(Blade Terminals)
DMS-20PC-1-FM
(Panel Mount)
Suggested wiring (user supplied)
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 without
notice. © 2015 Murata Power Solutions, Inc.
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-20PC-FM Series
Self-Powered, 3-Digit LED Display
AC Line Frequency Monitors
MPM_DMS-20PC-FM.H01 Page 2 of 2
Dimensions in inches (millimeters)
Tolerances: 2 PL Dec ±0.02 (±0.51)
3 PL Dec ±0.010 (±0.254)
Recommended panel cutout dimensions:
1.336 (33.93)W × 0.838 (21.29)H
Internal corner radii 0.032 (0.81) Max.
0.10
(2.5)
0.75
(19.1)
0.44
(11.2) 0.80
(20.3)
0.04
(1.016)
0.32
(8.1) 1.00
(25.4)
0.44
(10.2)
0.88
(20.4)
1.38
(35.1)
0.04
(1.016)
1.30
(33.0)
0.44
(10.2)
1.63 (41.1)
1.83 (46.5)
0.44
(10.2)
1.07
(27.2)
0.10
(2.5)
#6-32
UNC THD
#2-56 INSERT
0.156 (3.96 DEEP
Power Supply Polarity, Grounding, Fusing, and Wiring
1. Polarity and Grounding:
DMS-20PC-FM’s two ac-supply input terminals are not polarity sensitive, that
is, they have no “AC LO” or “AC HI” designations. These units do not include
nor require a connection to earth/chassis ground. 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 installa-
tion. Additional model-specifi c information is provided below.
2. UL Recognized Panel Mount Models with Screw Terminals:
DMS-20PC-FM AC frequency meters are not internally fused. The supply
wires feeding these meters must be fused with a 0.25A/250V time delay/time
lag fuse, in accordance with applicable regulatory codes. The rear threaded
standoff input-terminals are to be used only for powering the meter’s internal
circuitry; they must not be used to supply power to external loads.
The recommended wire size is 16AWG to 20AWG (1.31mm2 to 0.52mm2)
stranded copper wire. Wires must be properly stripped and attached to the
threaded standoffs such that their insulation is not pinched by the supplied
6-32 screws. Rated tightening torque for the 6-32 screws is 7 to 8 pound-
inches (0.8 to 0.9N-m). 300V UL rated wire suitable for the intended applica-
tion is required.
3. UL Listed Models with “Plug-in” Blade Terminals:
Plug-in DMS-20PC-1-FM-XF models are not internally fused and must be
protected by an external current limiting circuit breaker or fuse in accordance
with applicable regulatory codes. These models are designed to be plugged
into NEMA 1-15R, NEMA 5-15R, and NEMA 5-20R receptacles.
4. Description of the safety marks:
Caution, risk of electrical shock
Caution, risk of danger
Equipment is protected throughout by double or reinforced insulation
5. Cleaning Instructions: Gently clean with dry cloth only.
6. Caution: if the equipment is used in a manner not specifi ed by Murata
Power Solutions, the protection provided by the equipment may be
impaired.
C
®
US E156931
