DMS-20PC-0-AS-C MURATA-PS [Murata Power Solutions Inc.], DMS-20PC-0-AS-C Datasheet - Page 5

• Manufacturer Part Number: DMS-20PC-0-AS-C
• Manufacturer: MURATA-PS [Murata Power Solutions Inc.]

APPLICATIONS
Example: For a meter with a 2V full scale input (1.999 full scale
reading) and a desired display reading of "1000" (with an
input of 20mA), V
To calibrate the circuit of Figure 7, perform the following:
6. Power Supply Monitoring: One of the most common digital
1. With 4mA applied, adjust the 50kΩ potentiometer (R2) to
display a reading of "000" (assuming that is the desired
reading).
2. With 20mA applied, adjust the gain-adjust potentiometer
on the back of the meter to display a reading of "1000".
For different full scale readings, alter the value of R
accordingly.
panel meter applications involves monitoring the output voltage
of the system power supply — often this supply also powers the
meter itself. The low-power, red LED DMS-20PC-2-RL can be
configured to allow power supply monitoring over the range of
4.5-18Vdc. The circuit in Figure 8 uses a low-drop-out, three-ter-
minal regulator (LM-2931Z-5, available from National Semicon-
ductor) to provide regulated 5V-power to the meter.
4-20mA
85-264Vac
+
–
+
–
4.5 - 18Vdc
R
R
Shunt
Shunt
= 1.000V/0.016A = 62.5 Ohms
AC to DC Converter
R1
= 1.000V/(0.020 – 0.004)A
LM2931Z-5
DMS-PS1-CM
IN
Figure 7. 4-to-20mA Current Loop Operation
GND
Fsr
Figure 8. 4.5-18V Power Supply Monitor
DATEL
OUT
= 1.000 Volts
ANA COMM
50k
22μF
10V
(–) IN LO
(+) IN HI
R2
11
10
12
+
+5V SUP
+5V SUP
DISP EN
5V RET
1
DMS-20PC-1
DP2
1
2
3
5
REF
2
DISPLAY
ENABLE
11
IN
7
www.murata-ps.com
DMS-20PC-2-RL
(+) IN HI
5V RET
3
8
OUT
Shunt
REF
REF IN
8
REF OUT
7
12
(–) IN LO
3½ Digit, LED Display, Low-Cost, Subminiature
8. External Gain Adjustment: Connect REFERENCE OUT
7. Digital Ammeter: Digital ammeters are finding ever-increasing
12
(pin 8) to REFERENCE IN (pin 7) for normal, factory calibrated,
operation. Use the circuit shown in Figure 10 for applications
needing external gain adjustment. Calibration is performed
with a precise, near-full-scale, input voltage.
The LM-2931 was chosen because it has the following on-chip
protection features: reverse polarity, short circuit and thermal
runaway. When using other, higher-power, DMS-20PC models
with three-terminal regulators, be sure to consult the regula-
tor manufacturer's data sheet to ensure the regulator is being
utilized safely and correctly.
usage because analog-style ammeters (moving-vane types)
now cost roughly the same as their digital counterparts. Addi-
tionally, analog ammeters are not nearly as rugged as modern
digital panel voltmeters. Figure 9 illustrates a typical ammeter
application. The circuit uses a ±200mV input meter — the
preferred range for most ammeters — to measure the voltage
developed across a 0.1Ω current shunt. The circuit shown
represents a basic ammeter connection diagram. A detailed
application note describing digital dc ammeters is included in
DATEL's new Digital Panel Meter Databook.
CALIBRATOR
VOLTAGE
+
–
OUT
COM
Technical enquiries email: [e-mail], tel:
5Vdc
1.5 Amp (Load Current)
Figure 10. External Gain Adjustment
Figure 9. Basic DC Ammeter Circuit
(–) IN LO
(+) IN HI
5V RET
+5V SUP
DISP EN
COMM
5V RET
11
12
ANA
3
DP1
10
DMS-20PC Series
1
2
3
6
732, 1%
8.06k, 1%
(–) IN LO
DMS-20PC-1
NC
8
12
1
DMS-20PC-0
Digital Panel Voltmeters
= 10 to 20 Turns
REF
IN
7
R
0.150V
0.1W
Shunt
200
MPM_DMS_20PC.D02 Page 5 of 6
2k
1
1
17.4k, 1%
1
+5V IN
11
(+) IN HI
24.3k, 1%
(3.3 )
Load
W
8
REF OUT
7
REF IN
and ±200V models
Connections
for ±200mV
for ±2V, ±20V
Connections
models
[phone]