DMS-EB-RMS AC-to-RMS Converter Application Board for DMS-30PC/LCD Meters PRODUCT OVERVIEW FEATURES Displays true rms values of ac inputs ±0.5% accuracy for DMS-30PC-0 or DMS30LCD-0-5 ±2% accuracy for DMS-30PC-1 or DMS30LCD-1-5 Also works with DMS-40PC/LCD meters (see Ap Note 11) Description: The DMS-EB-RMS board allows the true rms value of ac signals to be displayed on 5V-powered DMS-30PC/LCD digital voltmeters. The meter/board combination has an input range of 0-750Vac with ±2V meters (1Vac resolution) or 0-199.9Vac with ±200mV meters (0.1Vac resolution). A built-in screw-terminal block reliably interfaces signal and power connections. The DMS-EB-RMS now accommodates user-installed modifications such as input-scaling resistors and isolated +5V dc/dc converters. Power and Safety Precautions: The DMS-EB-RMS’s AC HI and AC LOW inputs are not electrically isolated from its 5V supply (AC LOW is connected directly to 5V RETURN). When measuring any input signal which is derived from ac power mains, a dedicated (i.e., it only powers the DMS-EB-RMS), transformer-isolated +5V supply, with a minimum 1kV breakdown rating, must be used to power the DMS-EB-RMS board/meter combination. When measuring ac power mains inputs, never connect the DMS-EB-RMS’s 5V RETURN to chassis/earth ground anywhere in the system. Failing to follow these instructions could defeat any safety grounding and will place the system +5V power supply, and all its associated circuitry, at dangerously elevated ac-line potentials. In many applications, the MS-EB-RMS installation is required to meet electrical code requirements. To ensure safe operation, the DMS-EBRMS board should only be installed and serviced by technically qualified personnel. See DMS Application Note 11 for more details. C1 100μF + 5 6 (–) INPUT LO 12 7 8 (+) INPUT HI 11 CAV –VS OUT CF U1 +VS VIN COM CC 10 J1 4 5 3 6 2 7 1 8 C4 2.2μF + CAP– VOUT LV GND U2 CAP+ OSC V+ BOOST 4 C5 2.2μF 3 + 2 1 2 3 5V RETURN + SG1 4 DP3 C2 10μF 9 SG2 SG4 REF. OUT 8 REF. IN 1 +5V SUPPLY R1 988k 5 DP2 R2 988k R3 1.98k SG3 6 DP1 7 JP1 J4 J5 U3 3 1 VIN PS1 2 +V VOUT 4 +VIN DC/DC GND 2 1 –V –VOUT 3 J6 TB1 1 AC HI 3 AC LOW 5 +5V 6 5V Return Note: Components are user-supplied and not part of the standard product. Figure 1. DMS-EB-RMS Schematic Diagram 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-EB-RMS.B01 Page 1 of 2 DMS-EB-RMS AC-to-RMS Converter Application Board for DMS-30PC/LCD Meters Ordering Information DMS-EB-RMS-C AC-to-RMS conversion board DMS-BZL1-C Bezel assembly DMS-BZL2-C Bezel assembly with sealing gasket Functional Specifications (TA = +25°C, VCC = +5V) Vac Measurement Range: ±200mV meters ±2V meters 0 to 199.9Vac 0 to 750Vac Conversion Accuracy: 0-200Vac 0-750Vac ±0.5% ±2% Figure 2. DMS-EB-RMS Board Crest Factors 3, maximum Input Frequency Range 40Hz to 2kHz Primary Operating Power +5V (±5%) Current Consumption (Board only) +0.5mA typ., +1mA max. Operating Temperature Range 0 to +60°C Storage Temperature Range –20 to +75°C Humidity 0 to 95%, non-condensing Dimensions 2.02" (51.31mm)W x 0.83" (21.08mm)H 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 12/15/08 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: 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] Technical enquiries email: [email protected], tel: +1 508 339 3000 MPM_DMS-EB-RMS.B01 Page 2 of 2