DMS-20LCD-0-9B-C Murata Power Solutions Inc, DMS-20LCD-0-9B-C Datasheet - Page 5

• Manufacturer Part Number: DMS-20LCD-0-9B-C
• Description: Digital Panel Meters +-200mV / +9V Backlit Model
• Manufacturer: Murata Power Solutions Inc
• Type: 3 1/2 Digit, LCD Display Digital Panel Voltmeterr

Specifications of DMS-20LCD-0-9B-C

• Equipment Type: 3 1/2 Digit, LCD Display Digital Panel Voltmeter
• Input: +/- 200 mV
• Display Type: 3 - 1/2 Digit LCD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: DMS-20LCD-0-9B-C

APPLICATIONS
Example: For a meter with a 2V full scale input (1.999 full
scale reading) and a desired full scale display reading of
1000 (with an input of 20mA), V
To calibrate the circuit of Figure 7, perform the following:
1. With 4mA applied, adjust the 50k: potentiometer (R2) to
2. With 20mA applied, adjust the gain-adjust potentiometer on
6. Power Supply Monitoring: A popular application for DATEL’s low-
display a reading of "000" (assuming that is the desired
reading).
the back of the meter to display a reading of "1999". For different full
scale readings, alter the value of R
power LCD meters is monitoring the supply voltage in battery-oper-
ated portable equipment. Figure 8 demonstrates how a 9V-powered
DMS-20LCD can be used to monitor its own supply. The meter used
is the DMS-20LCD-1-9. A three-resistor voltage divider is used to
attenuate the battery voltage and also to satisfy the requirement that
the input voltages applied to pins 12 and 11 be at least 1.5 Volts above
and below the battery voltage applied to pins 1 (+BATTERY) and 3
(–BATTERY). The divider should be designed so that 1/10th the bat-
tery voltage falls across the inputs to the meter:
Where:
(R1 + R2 + R3)
4-20mA
+
–
120 VAC
R
R
R
Shunt
V
Shunt
Shunt
I
R2
Fsr
Fsr
Figure 7. 4-to-20mA Current Loop Operation
AC to DC Converter
R1
= R1 = V
= Full scale reading (in Volts)
= Relative full scale current (in Amps)
= 1.000V/(0.020 – 0.004)A
= 1.000V/0.016A = 62.5 Ohms
ANA COMM
50k
= 0.1
(5V-Powered Models)
(–) IN LO
Fsr
(+) IN HI
R2
/ I
Fsr
12
Fsr
11
10
+5V SUP
= 1.000 Volts
Shunt
DMS-20LCD-1-5
1
accordingly.
3
5V RET
8
REF OUT
7
REF IN
www.murata-ps.com/dpm
12
For +5V models, tie (–) IN LO to pin 3.
For +9V models, tie (–) IN LO to pin 10
7. External Gain Adjustment: Connect REFERENCE OUT
CALIBRATOR
Therefore, the 9V battery voltage appears to the meter inputs as 0.9V.
With the decimal point moved to its DP2 position
(pin 5 tied to pin 3), the meter reads 9.00 Volts.
The circuit can be calibrated by fi rst measuring the actual battery volt-
age with another meter and then adjusting the gain-adjust potentiom-
eter on the back of the DMS-20LCD until a similar reading is obtained.
If possible, the resistors in the divider should be ±1% metal-fi lm types
with TCR’s less than 50ppm/°C.
(pin 8) to REFERENCE IN (pin 7) for normal, factory calibrated,
operation. Use the circuit shown in Figure 9 for applications needing
external gain adjustment. Calibration is performed with a precise,
near-full-scale, input voltage.
VOLTAGE
3½ Digit, LCD Display Digital Panel Voltmeters
OUT
COM
REF OUT
REF IN
BATTERY
9V
7
8
+BAT
Figure 9. External Gain Adjustment
(–) IN LO
(+) IN HI
5V RET/
–BAT IN
Figure 8. Power Supply Monitor
1
DMS-20LCD Series
–
DMS-20LCD-1-9
11
12
COMM
3
(9V-Powered Models)
ANA
05 Apr 2011 MPM_DMS20LCD.B08 Page 5 of 6
10
732, 1%
–BAT
8.06k, 1%
3
NC
DMS-20LCD
8
c
DP2
= 10 to 20 Turns
5
REF
IN
7
email: [e-mail]
(+) IN HI
(–) IN LO
11
12
200
2k
c
c
+BAT IN
17.4k, 1%
+5V IN/
1
24.3k, 1%
45.3k
10.1k
45.3k
R1
R2
R3
and ±200V models
Connections
for ±200mV
for ±2V, ±20V
Connections
models