DMS-40LCD Series
4½ Digit, LCD Display Digital Panel Voltmeters
FEATURES
Scientific-grade accuracy, ±2 counts
Low power, typically 12.5mW
Miniature size:
2.17" x 0.92" x 0.43" (55mm x 23mm x 11mm)
Large (0.4”/10.2mm), enhanced-contrast, LCD display
Backlit displays optional
Epoxy-encapsulated, 12-pin DIP
Panel or pc-board mountable
3 differential, dual, input voltage ranges
Single +5V supply or 9V battery
User-selectable decimal point placement
Low-battery "BAT" annunciator
0 to +50°C temperature range
Low Cost
Offering a unique combination of low cost, scientific-grade accuracy (±2 counts),
component-like convenience and outstanding reliability, DMS-40LCD Series 4½ Digit DPM’s
provide the ultimate combination of price, precision and convenience. These miniature
(2.17” x 0.92” x 0.43”) digital voltmeters combine an advanced, autozeroing A/D converter,
a precision reference circuit and a large (0.4”/10.2mm high), easy-to-read LCD display in a
single, fully encapsulated, 12-pin DIP package. All models incorporate a built-in bezel and
are easily mounted in either panels or pc boards.
Each DMS-40LCD meter has a dual-range, differential, input configuration
(±200mV/±2V, ±2V/±20V or ±20V/±200V) and is available with a backlit or non-backlit
display. Input impedance is a minimum 800kΩ, and CMRR is typically 86dB (dc to 60Hz).
CMV is ±2V, and all models are overvoltage protected to ±250V (on their non-inverting
inputs).
All DMS-40LCD meters are fully functional and operate from a single +5V supply (draw-
ing 3.5mA max.) or a single 9V supply/battery (drawing 2.5mA max.). All models feature
autopolarity changeover and overrange indication. A display HOLD function is standard on
all non-backlit models.
Thanks to their rugged epoxy-based encapsulation and their advanced, factory-cal-
ibrated A/D converters, DMS-40LCD meters are able to withstand the harshest environ-
ments and never require adjustment or calibration. Plug-in convenience, long-term stability
and wide operating temperature range (0 to +50°C) make DMS-40LCD meters the right
solution for any high-accuracy DPM requirement.
SIMPLIFIED SCHEMATIC DIAGRAM
+5V
+5V SUPPLY/ 1
+BATTERY
–5V
RANGE 2
SELECT
DC/DC
CONVERTER
V–
+2.2V
5V RETURN/ 3
–BATTERY
4
A/D
CONVERTER
0 Vdc
J1
DATA
1.23V
REF.
10 ANALOG
COMMON
V+
R2
R1
11
12
(–) INPUT LO
0.01μF
(+) INPUT HI
DP 3
BAT
BAT
DP 2
5
9 HOLD/
BACKLIGHT
8
6
+5V
7 REFERENCE
IN/OUT
DC/DC converter is not used on 9V-powered models,
J1 is connected.
Hold function is not available on backlit models.
DP 4
DP 1
For full details go to
www.murata-ps.com/rohs
R1 = 100k on ±200mV/±2V (-0/1) models and 909k on all other models.
R2 is not used on ±200mV/±2V (-0/1) models.
R2 = 101k on ±2V/±20V (-1/2) models and 9.2k on ±20V/±200V (-2/3) models.
www.murata-ps.com
Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MPM_DMS40LCD.C02
Page 1 of 6
DMS-40LCD Series
4½ Digit, LCD Display Digital Panel Voltmeters
Performance/Functional Specifications
Typical at T
A
= +25°C and supply voltage = +5V (using the single-ended input circuit)
or +9V (using the differential input circuit), unless otherwise noted.
Analog Inputs
Full Scale Input Range:
DMS-40LCD-0/1
DMS-40LCD-1/2
DMS-40LCD-2/3
Input Impedence:
DMS-40LCD-0/1
DMS-40LCD-1/2
DMS-40LCD-2/3
Overvoltage Protection
Common Mode Voltage Range
CMRR
(dc to 60Hz)
Control Inputs
Decimal Pt. Placement
(Pins 4-6, 8):
Functionality
Logic Compatibility
Hold/Backlight Functionally
(Pin 9)
Backlit Models
Non-backlit Models
Performance
Sampling Rate
Accuracy (1 minute warm-up):
DMS-40LCD-0/1 (Vin = +0.19/1.9V)
DMS-40LCD-1/2 (Vin = +1.9V)
DMS-40LCD-1/2 (Vin = +19V)
DMS-40LCD-2/3 (Vin = +19/190V)
Zero Reading
(Vin = 0 Volts)
Temperature Drift
(0 = +50°C)
DMS-40LCD-0/1
DMS-40LCD-1/2
DMS-40LCD-2/3
–
–
–
–
“–001”
–
–
–
±2
±2
±3
±3
“000”
±0.4
±0.6
±0.6
±3
±3
±4
±4
“001”
±0.8
±1
±1
Cnts/°C
Cnts/°C
Cnts/°C
Counts
Counts
Counts
Counts
Accessories:
DMS-30-CP
DMS-BZL1-C
DMS-BZL2-C
DMS-EB-C
2.5 reading per second
Input Ranges:
0/1
= ±200mV/±2V
1/2
= ±2V/±20V
2/3
= ±20V/±200V
Add -C for RoHS
Leave blank for standard
models. Add
B
for
backlit models.
Tie to pin 3 to activate
TTL (on 5V-powered models)
Tie to pin 1 to activate
Tie to pin 3 to hold reading
100
0.8
0.8
–
–
–
1000
1
1
–
–
86
–
–
±250
±2
–
M
M
M
Volts
Volts
dB
–
–
–
±200/±2
±2/±20
±20/±200
–
–
–
mV/V
V/V
V/V
Min.
Typ.
Max.
Units
Physical/Environmental
Operating Temperature
Storage Temperature
Humidity (non-condensing)
Case Material
Weight
0
–20
0
–
–
–
+50
+75
95
°C
°C
%
Polycarbonate
0.75 ounces (21 grams)
Each model in the DMS-40LCD Series offers two input voltage ranges that are
user-selectable via pin strapping. 5V-powered models can be used to perform either
differential or single-ended measurements. 9V-powered models can only be used for
differential measurements.
Applies for transient or continuous overvoltages applied to (+) INPUT HI (pin 11)
with (–) INPUT LO (pin 12) properly connected. Pin 12 is not overvoltage protected
(see Figure 1). Voltages applied to pin 12 should not exceed the supply voltage.
Listed spec applies to 5V-powered models only. For 9V-powered models, both
(–) INPUT LO (pin 12) and (+) INPUT HIGH (pin 11) must always be at least 1.5V
above –BATTERY (pin 3) and at least 1.5V below +BATTERY (pin 1).
See Technical Notes.
Ordering Information
DMS-40LCD - 0/1 - 5
-C
Power Source:
5
= +5V
9
= +9V
Panel cutout punch
DMS-40 bezel assembly
DMS-40 bezel assembly with sealing gasket
Application/evaluation board with standard
MOLEX connector, decimal point solder pads
and attenuation resistor pads.
A panel-mount retaining clip is supplied with each model.
Power Supply Requirements (5V Models)
Supply Voltage
Supply Current:
Standard Models
Backlit Models
–
–
+2.5
+37
+3.5
+45
mA
mA
+4.75
+5.00
+5.25
Volts
TECHNICAL NOTES
1. Input Voltage Range Selection:
Each model in the DMS-40LCD
Series offers two, user-selectable, input voltage ranges as indicated
in the Performance/Functional Specifications Table and the Ordering
Information. To select the higher range of any device (such as the ±2V
range for the DMS-40LCD-0/1), connect pin 2 (RANGE SELECT) to
pin 1 (+5V SUPPLY/+BATTERY). To select the lower range, leave pin 2
open.
2. Decimal Point Placement:
The location of the decimal point is user-
selectable, and the decimal point control pins (DP1-DP4) are active low
functions. Select the appropriate decimal point by tying the appropriate
pin (pin 4, 5, 6 or 8) to pin 3 (5V RETURN/–BATTERY). Unused deci-
mal point location pins should be left open. For 5V-powered models,
the decimal location pins are TTL compatible and may be hard wired as
described above or driven with 5V TTL logic gates.
Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
Power Supply Requirements (9V Models)
Supply Voltage
Supply Current:
Standard Models
Backlit Models
Display
Display Type and Size
Polarity Indication
Overrange Indication
4½ digit, 0.4"/10.2mm high LCD
Autopolarity ("–" for negative Vin)
"–1_ _ _ _ " for negative inputs
"1_ _ _ _ " for positive inputs
–
–
+1.5
+37
+2.5
+45
mA
mA
+7.5
+9.00
+14.0
Volts
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MPM_DMS40LCD.C02
Page 2 of 6
DMS-40LCD Series
4½ Digit, LCD Display Digital Panel Voltmeters
3. Low Battery Annunciator:
The “BAT” annunciator in the upper
left-hand corner of the display turns on when the supply voltage for
5V-powered models falls below approximately +3.75V or when the
supply voltage for 9V-powered models falls below approximately 7.2V.
This function can not be disabled.
4. HOLD/BACKLIGHT (Pin 9) Function:
For non-backlit models, con-
necting pin 9 (HOLD/BACKLIGHT) to pin 3 (5V RETURN/
–BATTERY) will hold (continuously display) the last reading.
If not used, pin 9 should be left open for these models.
For backlit models, grounding pin 9 (i.e. connecting it to pin 3) turns on
the backlighting LED’s. 9V-powered backlit models function with supply
voltages up to +14V, however, activating the backlight with voltages
greater than 9.2V can damage the meter. Therefore, a 1/4 Watt series
resistor must be installed between pins 3 and 9 in these situations. The
value of the series resistor is determined using the following formula:
+BATTERY – 9.2V
0.035
Example: If +BATTERY (pin 1 with respect to pin 3) is +12.6V,
R
Series
=
+12.6 – 9.2V
0.035
R
Series
= 97 Ohms
In any backlit application, including those with supply voltages
< 9.2V, the current drawn by the backlight (and therefore the current
drawn by the meter) can be reduced by installing a 1/4 Watt resistor
between pins 3 and 9. The brightness of the backlight will be reduced
proportionately.
5. ANALOG COMMON (Pin 10):
This pin is connected to an internal,
low-noise, “relative” ground. It is used in certain “floating” measure-
ments as described in the Applications section of this data sheet and
Ap Note 3 of the DATEL Panel Meter Catalog.
Pin 10 should not be
connected to pin 3 (5V RETURN/–BATTERY) or to your system’s
analog ground.
6. REFERENCE IN/OUT (Pin 7):
This pin accesses the meter’s internal
reference and is used during the factory calibration procedure. Pin 7
should be left open in most common applications. It can be used in
certain “ratiometric” applications in which it is desireable for the meter’s
reference to track an external reference. See the Applications section
of the DATEL Panel Meter Catalog for more details.
7. Gain Adjust:
There is a gain-adjust potentiometer on the back of each
meter. It has approximately ±150 counts of adjustment range. Since
these devices essentially have no zero/offset errors, a gain adjustment
is effectively an overall accuracy adjustment. Though they may be
performed at any point (except zero), accuracy adjustments are most
effective when performed with higher level input signals.
Ohms
8. Soldering Methods:
All models in the DMS-40LCD Series easily
withstand most common wave soldering operations. We recommend,
however, you evaluate the effects your particular soldering techniques
may have on the meter’s plastic case and high-precision electrical
performance. We recommend the use of water-soluble solders and
thorough cleaning procedures.
9. Suggested Mating Connectors:
Panel mounted:
Connector housing
DATEL P/N 39-2079400
Terminal type
DATEL P/N 39-2099090
Crimping tool
DATEL P/N 39-2099000
Wire size
22 to 26 AWG
Insulation diameter
0.062” (1.57mm) maximum
Stripping length 0.100 to 0.125” (2.54 to 3.17mm)
Board mounted:
Socket
DATEL P/N 39-2359625
R
Series
=
Ohms
APPLICATIONS
DMS-40LCD meters are available in either 5V-powered or 9V-powered
models. 9V devices operate directly from 7.5V to 14V supplies (usually
batteries) without the need for external voltage regulators. 9V devices,
however, can not be used to measure voltages referenced to the negative
battery terminal (pin 3) because the minus input to the meter (pin 12, (–)
INPUT LO) must always be at least 1.5V above pin 3. 9V-powered meters
can only be used to make differential and not single-ended measurements.
5V-powered devices operate from any well-regulated +5V supply and will
accurately measure voltages both above and below pin 3 (5V RETURN) in
either single-ended or differential configurations.
1. Single-Ended Input Configurations:
True single-ended measure-
ments can only be made with 5V-powered meters. The circuit of Figure
2 avoids problems normally associated with ground loop currents.
Separate ground runs should be used for 5V RETURN (pin 3) and (–)
INPUT LO (pin 12).
DMS-40LCD-0/1-5
11
(+) IN HI
+
V
IN
–
12
(–) IN LO
1
+5V SUP
2
RANGE
6
DP1
3
5V RET
120 VAC
DATEL
UPA-5/500
AC to DC Converter
Figure 2. Single-Ended Input Configuration
(5V-Powered Models)
www.murata-ps.com
Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MPM_DMS40LCD.C02
Page 3 of 6
DMS-40LCD Series
4½ 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
DMS-40LCD Series
4½ Digit, LCD Display Digital Panel Voltmeters
APPLICATIONS
5. Process Control (4-to-20mA) Measurements:
In many common
process-control applications, a 4-to-20mA current loop is used to
transmit information. Because DMS-40LCD meters have such high
input impedance, a simple shunt resistor across the meter’s input can
be used to convert the loop current to a voltage. See Figure 7. The
value of the shunt resistor is a function of the scaling requirements of
the particular application and can be calculated using the following
equation:
R
Shunt
= R1 = V
Fsr
/ I
Fsr
Where:
V
Fsr
= Full scale reading (in Volts)
I
Fsr
= Relative full scale current (in Amps)
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
Fsr
= 1.000 Volts
R
Shunt
= 1.000V/(0.020 – 0.004)A
R
Shunt
= 1.000V/0.016A = 62.5 Ohms
To calibrate the circuit of Figure 7, perform the following:
1. With 4mA applied, adjust the 50k potentiometer (R2) to
display a reading of "0000" (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 "19999".
For different full scale readings, alter the value of R
Shunt
accordingly.
11
(+) IN HI
10
ANA COMM
12
(–) IN LO
1
+5V SUP
2
RANGE
3
5V RET
6. Power Supply Monitoring:
A popular application for DATEL’s low-
power LCD meters is monitoring the supply voltage in battery-operated
portable equipment. Figure 8 demonstrates how a 9V-powered DMS-
40LCD can be used to monitor its own supply. The meter used is the
DMS-40LCD-0/1-9 configured for its ±2V input range (pin 2 connected
to pin 1). A three-resistor voltage divider is used to attenuate the bat-
tery 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 battery voltage falls
across the inputs to the meter.
R2
= 0.1
(R1 + R2 + R3)
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 9.000 Volts.
The circuit can be calibrated by first measuring the actual battery volt-
age with another meter and then adjusting the gain-adjust potentiom-
eter on the back of the DMS-40LCD until a similar reading is obtained.
If possible, the resistors in the divider should be ±1% metal-film types
with TCR’s less than 50ppm/°C.
DMS-40LCD-0/1-9
11
(+) IN HI
R1
45.3k
12
(–) IN LO
R2
10.1k
DMS-40LCD-0/1-5
1
+BAT
2
RANGE
+
3
–BAT
5
DP2
R3
45.3k
+
9V
BATTERY
–
4-20mA
R1
R2
Figure 8. Power Supply Monitor
(9V-Powered Models)
–
50k
120 VAC
DATEL
UPA-5/500
AC to DC Converter
Figure 7. 4-to-20mA Current Loop Operation
(5V-Powered Models)
www.murata-ps.com
Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MPM_DMS40LCD.C02
Page 5 of 6
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