DMS-40LCD Series
4�½ Digit, LCD Display Digital Panel Voltmeters
APPLICATIONS
2. Differential Input Configurations:
Differential measurements can be
made with either 5V-powered or 9V-powered meters. Figure 3, though
not a practical real-world application, uses a voltage divider to demon-
strate the concept of a differential input signal. Be careful not to exceed
the ±2V common mode voltage limitation for 5V-powered meters.
4. Floating Signal Source Measurements:
Floating signals can be
measured using the circuits shown in Figures 5 and 6. Figure 5 uses
a 5V-powered meter. Figure 6 uses a 9V-powered meter. Both figures
show a DMS-40LCD-0/1 with pin 2 tied to pin 1 yielding a ±2V input
range. Connecting pin 10 (ANALOG COMMON) to (–) INPUT LO (pin
12) provides the reference point for the meter’s input.
A “floating” input is a signal that has no galvanic connection to the
meter’s power supply. In the figures below, the 1.5V battery illustrates a
true floating input.
11
(+) IN HI
1
+5V SUP
2
RANGE
3
5V RET
R3
1k
DMS-40LCD-0/1-5
6
DP1
11
(+) IN HI
R1
1k
12
(–) IN LO
R2
1k
DMS-40LCD-0/1-5
1.5V
CELL
+
–
10
ANA COMM
12
(–) IN LO
1
+5V SUP
2
RANGE
3
5V RET
6
DP1
120 VAC
DATEL
UPA-5/500
AC to DC Converter
Figure 3. Differential Input Configuration
(5V-Powered Models)
120 VAC
DATEL
UPA-5/500
AC to DC Converter
3. Engineering Scaling:
For measuring voltages greater than the full
scale input range of a given meter, the input signal must be attenuated.
A simple voltage divider (similar to that shown in Figure 4) will scale
the input to within the range of the selected meter. R1 and R2 should
be precision, ±1%, metal film resistors with absolute TCR’s less than
50ppm/°C. See Ap Note 4 for more information on engineering scaling.
50k < R1 + R2 < 10M
R2
R1 + R2
DMS-40LCD-0/1-5
1.5V
CELL
Figure 5. Floating Input Measurements
(5V-Powered Models)
11
(+) IN HI
DMS-40LCD-0/1-9
+
–
10
ANA COMM
12
(–) IN LO
1
+ BAT
2
RANGE
+
9V
BATTERY
–
3
–BAT
6
DP1
x V
IN
= Reading
11
(+) IN HI
12
(–) IN LO
3
5V RET
Figure 6. Floating Input Measurements
(9V-Powered Models)
R1
V
IN
R2
+
–
Figure 4. Input Attenuation Circuit
www.murata-ps.com
Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MPM_DMS40LCD.C02
Page 4 of 6
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