DMS-20RM Series True-rms ac Voltmeters with Isolated Inputs 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 vibration 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 ■ Measures the rms value of complex ac voltages ■ Three input ranges: 20Vac, 200Vac and 300Vac ■ Two operating-supply options: 85-264Vac, or +10-40Vdc ■ Input circuit fully isolated from operating power supply ■ 47-1kHz input frequency range ■ Fully encapsulated plastic package measures 1.38” x 0.88” (35mm x 22.4mm) ■ Large, easy-to-read, red LED display is visible from 12 feet (4m) TYPICAL WIRING DIAGRAMS AC POWER SUPPLY AC POWER SUPPLY A A B B TB1 TB1 TB1 TB2 TB2 AC VOLTAGE TO BE MEASURED + - Figure 1B. Powered by and measuring the same AC power source. Figure 1A. Powered by AC supply while measuring separate AC signal. A 10-40Vdc DC POWER SUPPLY B TB2 AC VOLTAGE TO BE MEASURED Figure 2. Powered by DC power supply while measuring AC signal. For full details go to www.murata-ps.com/rohs www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_DMS-20RM.A02 Page 1 of 4 DMS-20RM Series True-rms ac Voltmeters with Isolated Inputs Performance/Functional Specifications Typical at TA=+ 25ºC with 60Hz sine-wave input, unless otherwise noted Full-Scale Input Voltage (TB2) DMS-20RM-1 DMS-20RM-2 DMS-20RM-3 Frequency Range Min. Typ. Max. Units 0 0 0 — — — 19.99 199.9 300 Vac Vac Vac 47 60 1000 Hz Performance Sampling Rate Accuracy ➀ Measurement Type ±0.4%FS ±2 counts with 60Hz sine wave input DMS-20RM-3-DC2-R-C 0 to 300Vac, DC Powered ±0.2 ±0.4 Counts/ºC 000 001 Counts — — Vdc Power Supply Voltage (TB1) DMS-20RM-X-AC1 85 — 264 Vac/47-63Hz DMS-20RM-X-DC2 +10.0 — +40.0 Vdc DMS-20RM-X-AC1 — 30 50 mA/47-63Hz DMS-20RM-X-DC2 — 10 15 mAdc Power Supply Current (TB1, ➁) Terminal Block Wiring (TB1 and TB2) 16-22AWG, Solid or stranded Insulation Strip Length 0.250 inches 3.6 pound-inches (0.4Nm) Rated Voltage 300Vac Display 3½ Digit LED, 0.37”/9.4mm high Overrange Indication “1___” Fixed, model dependent (see full-scale input voltage above) Physical/Environmental Operating Temperature -25 Storage Temperature — +60 ºC -40 — +75 ºC Humidity (non-condensing) 0 — 85 % Dimensions Model dependent; see product datasheet. Weight: 0 to 300Vac, AC Powered 0 to 199.9Vac, DC Powered -001 Decimal Point 0 to 199.9Vac, AC Powered DMS-20RM-3-AC1-R-C 0 to 19.99Vac, DC Powered 2000 Display Type and Size DMS-20RM-2-AC1-R-C DMS-20RM-2-DC2-R-C Breakdown Voltage, TB1 to TB2 Screw Tightening Torque 0 to 19.99Vac, AC Powered DMS-20RM-1-DC2-R-C Zero-Volt Reading (within 30 sec.) Wire Size DMS-20RM-1-AC1-R-C 2.5 reading per second rms responding, Crest Factors of 1-5 Temperature Drift (0 to 60ºC) ORDERING INFORMATION 1.3 Ounces (36 grams) nominal ➀ Specified accuracy applies to inputs with crest factors (CF) up to 2.0, where CF = Vpeak/Vrms. Crest factors of 2 to 5 introduce an additional error of ±3% of full scale. Voltmeters are calibrated with a near full-scale, 60Hz sine-wave input. ➁ Specified maximum power supply currents are steady state; larger surge currents can occur at initial application of power. www.murata-ps.com IMPORTANT! To ensure safe and reliable operation, DMS-20RM ac voltmeters must be installed and serviced by qualified technical personnel. Contact Murata Power Solutions if there is any doubt regarding installation and/or operation. TECHNICAL NOTES 1. Measurement Type: DMS-20RM series ac voltmeters employ a precision rms-to-dc converter and a high-precision voltage reference to measure and display the rms value of complex ac waveforms. Please note, the rear-mounted potential transformer is used to isolate the input signal being measured (TB2) from the ammeter’s operating power source connected to TB1. Do not pass any conductors through this transformer’s center hole as this will introduce significant measurement errors. 2. Wiring: All power supply and input signal wiring must be 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, and Grounding: As shown in Figures 1A and 1B, the two power supply inputs, TB1-A and TB1-B, on ac-powered DMS-20RM voltmeters (“-AC1” suffix) are not polarity sensitive, that is, they have no “AC LO” or “AC HI” designations. Also, ac-powered models do not include or require a connection to earth/chassis ground. DC-powered models (‘-DC2’ suffix) are reverse-polarity protected, and must be connected as shown in Figure 2 for proper operation. DMS-20RM ac voltmeters are not internally fused. If fusing is required it must be externally installed according to the supply wire’s maximum amperage rating. 4. Calibration: Periodic recalibration of DMS-20RM voltmeters is not required under normal, indoor operating environments. If calibration is necessary, it should only be performed by qualified technical personnel. Calibration is performed with potentially lethal voltages applied to the DMS-20RM 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 DMS-20RM ac voltmeters. Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_DMS-20RM.A02 Page 2 of 4 DMS-20RM Series True-rms ac Voltmeters with Isolated Inputs MECHANICAL SPECIFICATIONS 2.01 (51.1) 1.00 (25.4) 0.040 (1.02) 0.040 (1.02) 1.30 (33.0) 1.38 (35.1) 0.040 (1.02) 0.800 (20.3) 0.880 (22.4) 1.600 (40.6) FRONT VIEW BACK VIEW A B TB1 - Power Supply CAL. TB2 - Input Signal RECOMMENDED DRILL AND PANEL CUTOUT www.murata-ps.com Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_DMS-20RM.A02 Page 3 of 4 DMS-20RM Series True-rms ac Voltmeters with Isolated Inputs Panel Installation All connections to DMS-20RM ac voltmeters must be made after the meter is securely attached to the panel, with all associated ac supply power sources de-energized (off). The installed wire positions should be such that minimal forces are applied to terminal blocks TB1 and TB2. In high-vibration environments, proper strain reliefs must be used for all wiring. To ensure a secure panel-mount installation, MPS recommends using the DMS-BZL4-C bezel assembly (with sealing gasket) supplied with each DMS20RM voltmeter. See the ‘Mechanical Specifications’ section for detailed cutout and voltmeter dimensions. Step 1. Step 2. Following the four-step sequence shown in Figure 3 — being careful not to apply excessive force or twisting motions — insert the DMS-20RM into the panel opening. When using the DMS-BZL4-C, install its sealing gasket so it is positioned between the voltmeter’s front flange and panel front surface (see Mechanical Specifications). Be sure to use and securely tighten all four screws supplied with the bezel assembly. Step 3. Step 4. Figure 3. Panel Installation USA: Murata Power Solutions, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A. Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356 www.murata-ps.com email: [email protected] ISO 9001 and 14001 REGISTERED Toronto, Tel: (866) 740-1232, email: [email protected] UK: Milton Keynes, Tel: +44 (0)1908 615232, email: [email protected] France: Montigny Le Bretonneux, Tel: +33 (0)1 34 60 01 01, email: [email protected] Germany: München, Tel: +49 (0)89-544334-0, email: [email protected] Japan: Tokyo, Tel: 3-3779-1031, email: [email protected] Osaka, Tel: 6-6354-2025, email: [email protected] China: Shanghai, Tel: +86 215 027 3678, email: [email protected] Guangzhou, Tel: +86 208 221 8066, email: [email protected] Singapore: Parkway Centre, Tel: +65 6348 9096, email: [email protected] 04/07/09 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. © 2008 Murata Power Solutions, Inc. www.murata-ps.com Mansfield (MA), Tel: (508) 339-3000, email: [email protected] Canada: Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_DMS-20RM.A02 Page 4 of 4