® ® DMS-EB-RMS AC-to-RMS Converter Application Board for DMS-30PC/LCD Meters Actual Size Purchase on-line at www.datel.com Features Technical Notes • Displays true rms values of ac inputs • ±0.5% accuracy for DMS-30PC-0 or DMS-30LCD-0-5 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. • Also works with DMS-40PC/LCD meters (see Ap Note 11) Functional Specifications (TA = +25°C, VCC = +5V) Vac Measurement Range: ±200mV meters 0 to 199.9Vac ±2V meters 0 to 750Vac Conversion Accuracy: 0-200Vac ±0.5% 0-750Vac ±2% Crest Factors 3, maximum 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 DMS-EB-RMS installation is required to meet electrical code requirements. To ensure P S 1 J 1 R 3 J 6 R 2 J 2 1 1 2 safe operation, the DMS-EB-RMS board 2 U 1 1 1 J P 1 should only be installed and serviced by U 3 1 0 R 1 J 5 J 3 J 4 technically-qualified personnel. See DMS C 1 T B 1 9 C 5 1 Application Note 11 for more details. 8 C 4 2 3 5 S G 3 6 + 6 (–) INPUT LO 12 7 8 (+) INPUT HI 11 CAV –VS OUT CF U1 +VS VIN COM CC 10 J1 9 C2 10µF 4 5 3 6 2 7 1 C4 2.2µF CAP– VOUT GND LV U2 CAP+ OSC 8 + Storage Temperature Range –20 to +75°C V+ BOOST 4 C5 2.2µF 3 + 2 2 3 5V RETURN + SG1 4 DP3 SG2 5 DP2 REF. OUT 8 REF. IN 1 +5V SUPPLY 1 SG4 Humidity 0 to 95%, non-condensing 4 C1 100µF 5 Operating Temperature Range 0 to +60°C 1 C 2 S G 4 Primary Operating Power +5V (±5%) Current Consumption (Board only) +0.5mA typ., +1mA max. U 2 7 Input Frequency Range 40Hz to 2kHz S G 2 S G 1 • ±2% accuracy for DMS-30PC-1 or DMS-30LCD-1-5 R1 988k R2 988k R3 1.98k SG3 6 DP1 7 JP1 Dimensions 2.02" (51.31mm)W x 0.83" (21.08mm)H J4 J5 U3Q 3 1 VIN Ordering Information DMS-BZL1 DMS-BZL2 AC-to-RMS conversion board Bezel assembly Bezel assembly with sealing gasket 4 +VIN +V DC/DC 1 DMS-EB-RMS PS1Q 2 VOUT GND 2 –V –VOUT 3 J6 TB1 1 AC HI 3 AC LOW 5 +5V 6 5V Return Q Components are user-supplied and not part of the standard product. Figure 1. DMS-EB-RMS Schematic Diagram DS-0398A 1/98 DATEL, Inc., Mansfield, MA 02048 (USA) • Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 • Email: [email protected] • Internet: www.datel.com DATEL 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. The DATEL logo is a registered DATEL, Inc. trademark.