Murata Power Solutions’ new DMR20-1-FM is the world’s smallest, self-powered, ac line
frequency monitor. Simply connect 85 to 264Vac (45-65Hz) power and the meter is fully
operational—no additional components are required. The unit can also measure distorted
120Vrms power sources with triangle and square waveforms, as well as quasi sine wave
outputs of dc to ac power inverters.
An ultra-stable, quartz-crystal controlled microprocessor provides accuracies of ±0.02Hz
over the operating temperature range of -25 to +60°C. DMR20-1-FM frequency moni-
tors feature a large, 0.30”/7.6mm, bright LED display that can be easily read from 10 feet
away (3 meters). A built-in resettable fuse and out-of-range indication assures long term
reliability.
The DMR20-1-FM is housed in a rugged, round polycarbonate case that provides excellent
protection against moisture, dust, shock and vibration. Panel installation is straightforward:
using 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 nut and gasket are designed to provide moisture ingress protection to
IP67/NEMA 6.
DMR20-1-FM is exactly the same size as Murata Power Solutions’ DMR20-1-ACV (ac volts),
DMR20-10-DCM (dc volts), and DMR20-1-TMP (temperature) digital panel meters.
➀
Operation and accuracy with ac inputs above or below this range are not specified.
Operation from waveforms other than sine waves is limited to 120Vrms. See Technical
Note 1 for additional information.
Performance/Functional Specifi cations
Typical at Ta = +25°C, Vin = 250Vac / 60Hz sine wave, unless
otherwise noted
AC Input (TB1)
Voltage Range
➀
85 to 264Vac (45-65 Hz)
Current Consumption
250Vac/60Hz: 12mA (max.)
UL/IEC61010-1
Measurement Category II
Performance
Sampling Rate
2-3 readings/second
Resolution
0.01Hz
Accuracy @ +25°C
±0.01Hz (typ.), ±0.02Hz (max.)
Temperature Drift
±0.0005Hz/°C (–25 to +60°C)
Mechanical
Dimensions
1.5" diameter x 1.1” depth
(38 x 28mm)
Display Type
Four digit, LED, 0.30” high (7.6mm)
Weight
0.9 ounces (25.5 grams)
Case Material
Polycarbonate
Terminal Block Torque
2.2 lb·in (0.25 N·m) ±20%
Wire Size And Type
18-22AWG (0.83-0.33mm
2
) 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%
Ordering Information
DMR20-1-FM-R-C
85 to 264Vac frequency 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” suffi x denotes RoHS compliance.
www.murata-ps.com
www.murata-ps.com/support
For full details go to
www.murata-ps.com/rohs
DMR20-1-FM
Self-Powered,
LED Display, AC Line Frequency Monitor
MPM_DMR20-1-FM.A02
Page 1 of 3
NANO
FEATURES
Self-powered from 85 to 264Vac / 45-65Hz supplies
0.01Hz resolution & quartz crystal accuracy and
stability
Installs in “oiltight” 1.20 inch (30.5mm) round
cutouts
Four-digit LED display with out-of-range indication
Digital replacement for analog panel meters
Self-resetting internal fuse for long-term reliability
Supplied with EPDM rubber gasket and plastic hex nut
Provides moisture ingress protection to IP67/NEMA 6
Screw-style input terminal block simplifies installation
Knockout punches and tooling available
Approvals to UL/cUL/IEC/ 61010-1
E156931
