DMS-EB-RMS
www.murata-ps.com
AC-to-RMS Converter Application Board for DMS-30PC/LCD Meters
PRODUCT OVERVIEW
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 modi cations such as input-scaling resistors and isolated +5V dc/dc
converters.
Power and Safety Precautions: The DMS-EB-RMSs AC HI and AC LOW inputs are not electri-
cally isolated from its 5V supply (AC LOW is connected directly to 5V RETURN). When measuring any
FEATURES
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
Displays true rms values of ac inputs
DMS-EB-RMS board/meter combination. When measuring ac power mains inputs, never connect the
0.5% accuracy for DMS-30PC-0 or DMS-
DMS-EB-RMSs 5V RETURN to chassis/earth ground anywhere in the system. Failing to follow these
30LCD-0-5
instructions could defeat any safety grounding and will place the system +5V power supply, and all its
2% accuracy for DMS-30PC-1 or DMS-
associated circuitry, at dangerously elevated ac-line potentials. In many applications, the MS-EB-RMS
30LCD-1-5
installation is required to meet electrical code requirements. To ensure safe operation, the DMS-EB-
Also works with DMS-40PC/LCD meters (see Ap
RMS board should only be installed and serviced by technically quali ed personnel. See DMS
Note 11)
Application Note 11 for more details.
C1 100F
+
5 4 4
5
CAV VS VOUT CAP
6 3 6 3 C5
() INPUT LO 12 +5V SUPPLY
OUT CF LV GND 1
2.2F
U1 U2 +
7 2 7 2
+VS
VIN OSC CAP+
8 1 8 1
(+) INPUT HI 11 COM CC 2
V+ BOOST
C4
10 J1
3 5V RETURN
2.2F
+
+ SG1
C2
4 DP3
9
10F
SG2
SG4
5 DP2
REF. OUT 8
R1 R2 R3
988k 988k 1.98k
SG3
6 DP1
REF. IN 7
JP1
J4 J5
U3
PS1
1 VIN 3 2 4
+VIN
+V
VOUT
DC/DC
GND 2
3
V VOUT
1
J6
TB1
1 3 56
Note: Components are user-supplied
AC HI AC LOW +5V 5V Return
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/support
MPM_DMS-EB-RMS.C01 Page 1 of 2DMS-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 Speci cations
(TA = +25C, VCC = +5V)
Vac Measurement Range:
Figure 2. DMS-EB-RMS Board
200mV meters 0 to 199.9Vac
2V meters 0 to 750Vac
Conversion Accuracy:
0-200Vac 0.5%
0-750Vac 2%
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 +60C
Storage Temperature Range
20 to +75C
Humidity
0 to 95%, non-condensing
Dimensions
2.02" (51.31mm)W x 0.83" (21.08mm)H
This product is subject to the following operating requirements
Murata Power Solutions, Inc.
and the Life and Safety Critical Application Sales Policy:
11 Cabot Boulevard, Mans eld, MA 02048-1151 U.S.A.
Refer to: