For full details go to

www.murata-ps.com/rohs

www.murata-ps.com

DMS-20RM Series

True-rms ac Voltmeters with Isolated Inputs

MPM_DMS-20RM.A02 Page 1 of 4

Murata Power Solutions’ DMS-20RM series are four-wire, self-contained ac voltmeters

that measure and display the true-rms values of complex ac waveforms. Because the input

circuitry is electrically isolated from the unit’s operating power source, these voltmeters

can measure signals down to zero volts. No external isolation transformers or auxiliary

power supply conditioning components are required. Simply connect the input signal and a

source of operating power (85-264Vac, or an optional +10-40Vdc) to the two rear-mounted

terminal blocks and the unit is fully operational.

DMS-20RM rms voltmeters are available in a choice of three input ranges: 20Vac

(with 0.01V resolution); 200Vac (0.1V resolution); and 0-300Vac (1V resolution). An input

frequency range of 47-1kHz makes these voltmeters ideal for all ac voltage monitoring

applications. And, unlike conventional, average-responding products, these meters can

measure and accurately display the true-rms value of triangle waves, square waves, or

other irregularly shaped waveforms with 0.4% full-scale accuracy.

The large (0.37”/9.4mm), bright red LED display makes the DMS-20RM ac voltmeters

easily readable from as far as 12 feet (4 meters). All units are packaged in a red-filter case

with a built-in bezel; these meters are fully encapsulated to make them moisture and vibra-

tion resistant. Their miniature size is perfect for high-end consumer electronics, laboratory

instrumentation, alternative power generators and other products requiring precise ac line

monitoring.

FEATURES

0.88” (35mm x 22.4mm)

feet (4m)

　

TYPICAL WIRING DIAGRAMS

AC POWER

SUPPLY

AC VOLTAGE

TO BE MEASURED

10-40Vdc

DC POWER

SUPPLY

AC VOLTAGE

TO BE MEASURED

+

-

AC POWER

SUPPLY

TB1

TB2

A

B

TB1

TB2

A

B

TB1

TB2

A

B

Figure 1A.

Powered by AC supply while measuring separate AC signal.

Figure 2.

Powered by DC power supply while measuring AC signal.

Figure 1B.

Powered by and measuring the same AC power source.