DMS-30DR Series
Daylight Readable, 3½ Digit Panel Meters
with Auto-Dimming LED Displays
PATENT PENDING
FEATURES
■
Super-bright LED displays are readable in
direct sunlight!
Autodim circuitry automatically adjusts
display brightness
Includes external brightness adjustment
Large (0.56”/14.2mm) easy-to-read red
LED display
High reliability alternative to LCD displays
Ideal for automotive, industrial, and marine
applications
Encapsulated package mounts in panels or
pc-boards
Miniature housing: 2.17” x 0.92” x 0.56”
(55mm x 23mm x 14mm)
4 differential input ranges provide ±1 count
accuracy
Single +5V supply; Less than 1-Watt power
consumption
0 to +60°C operating temperature range
1
■
C&D Technologies’ new DMS-30DR Series are the first digital panel meters to offer LED
displays that are readable in direct sunlight—no special filters or shading devices are required.
Their Autodim circuit automatically adjusts the display’s brightness to suit viewing environments
ranging from total darkness to full, brilliant sunlight. A user-accessible brightness adjustment pin
enables custom intensity settings or display matching in multiple display applications. Washed
out, hard-to-read digital readouts are a thing of the past!
Until now, users whose instrumentation required daylight visibility had to settle for less
reliable LCD display technology. However, in order to remain legible in low ambient light, LCDs
require complex, power-hungry backlighting circuitry. And, these displays typically suffer from
very narrow viewing angles. In contrast, DMS-30DR Series LED-based displays’ power consump-
tion drops as ambient light decreases, and their viewing angle extends to nearly 180 degrees
vertically and horizontally.
All models operate from a single +5V supply, and draw as little as 7mA when operated in total
darkness—that’s less than 1/10 Watt. At maximum brightness power consumption is typically
less than 200mA (1 Watt). DMS-30DR voltmeters are available in four differential input voltage
ranges: ±200mV, ±2V, ±20V and ±200V. Input impedance is 1,000 megohms for the ±200mV
and ±2V inputs and 1 megohm for the ±20V and ±200V inputs. CMRR for all devices is 86dB,
and inputs are overvoltage protected to ±250V. Each meter incorporates a precision, ultra-stable
voltage reference and is factory calibrated prior to encapsulation.
The small size (2.17” x 0.92” x 0.56”) of DMS-30DR meters is achieved by integrating their
display, Autodim display drivers, light sensor, reference circuit, and A/D converter into in a rugged
epoxy-encapsulated assembly. The device’s 12-pin, component-like, DIP package is both vibra-
tion and moisture proof, making them ideal for harsh environments. Each package incorporates a
built-in color filter and bezel, and is easily mounted in either panels or pc boards.
■
■
■
■
■
■
■
■
■
+5V SUPPLY
+5V
+5V
12
0.01µF
(–) INPUT LO
R2
(1)
EXTERNAL BRIGHTNESS
ADJUSTMENT
2
DC/DC
CONVERTER
+5V
–5V
–5V
R1
909k
11
(+) INPUT HI
5V RETURN
3
–5V
A/D
CONVERTER
10 ANALOG
COMMON
1.225V
REF.
1.82k
DP 3
4
0 Vdc
DATA
9
+1.225V REFERENCE OUT
DP 2
5
LIGHT
SENSOR
8
+5V
REFERENCE OUT
DP 1
6
7
REFERENCE IN
(1)
R2 is not used on ±200mV (-0) models or ±2V (-1) models.
R2 = 100k on ±20V (-2) models and 9.1k on ±200V (-3) models.
Figure 1. DMS-30DR Simplified Schematic
DIGITAL PANEL METERS
MPM_DMS-30DR_A01
Page 1 of 6
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DMS-30DR Series
S U N L I G H T R E A D A B L E , AU T O - D I M M I N G L E D D I S P L AY M E T E R S
Performance/Functional Specifications
Typical at T
A
= +25°C and supply voltage = +5V using the single-ended input circuit,
unless otherwise noted.
Analog Inputs
Full Scale Input Range:
DMS-30DR-0
DMS-30DR-1
DMS-30DR-2
DMS-30DR-3
Input Impedence:
DMS-30DR-0, -1
DMS-30DR-2, -3
Overvoltage Protection
➀
Common Mode Voltage Range
CMRR
(dc to 60Hz)
Control Inputs
➁
Decimal Point Placement
(Pins 4-6)
Ext. Bright
(Pin 2)
Performance
Sampling Rate
Accuracy (3 minute warm-up):
DMS-30PC-0 (Vin = +0.19V)
DMS-30PC-1 (Vin = +1.9V)
DMS-30PC-2 (Vin = +19V)
DMS-30PC-3 (Vin = +190V)
Zero Reading
(Vin = 0 Volts)
Temperature Drift
(0 = +60°C)
+1.225V Reference Output
(Pin 9)➁
Power Supply Requirements
Supply Voltage
Supply Current:
Full Sunlight
Total Darkness
Display
Display Type and Size
Polarity Indication
Overrange Indication
Physical/Environmental
Operating Temperature
Storage Temperature
Humidity (non-condensing)
Case Material
Weight
0
–40
0
–
–
–
+60
+75
95
°C
°C
%
3½ digit, 0.56"/14.2mm high LED
Autopolarity ("–" for negative Vin)
"–1_ _ _ " for negative inputs
"1_ _ _ " for positive inputs
–
–
+150
3
+250
5
mA
mA
+4.75
+5.00
+5.25
Volts
–
–
–
–
“–001”
–
+1.215
±1
±1
±2
±2
“000”
±0.2
+1.225
±3
±3
±3
±3
“001”
±0.4
+1.235
Cnts/°C
Volts
Counts
Counts
Counts
Counts
2.5 reading per second
Tie to pin 3 to activate
See Technical Note 1
–
–
–
–
–
100
0.9
–
–
–
1000
1
–
–
86
–
–
±250
±2
–
MΩ
MΩ
Volts
Volts
dB
±200
±2
±20
±200
–
–
–
–
mV
Volts
Volts
Volts
Min.
Typ.
Max.
Units
Ordering Information
DMS-30DR- 1 - R - C
Input Range:
0
= ±200mV
1
= ±2V
2
= ±20V
3
= ±200V
Accessories:
DMS-EB-C
DMS-EB-RMS-C
DMS-PS1-CM-C
DMS-30-CP
PATENT PENDING
RoHS Compliant
LED Color:
R
= Red
Multi-purpose (gain/offset, 4-20mA, etc.)
For true rms measurements of ac voltages
+5V/1.0A AC/DC power supply module
Panel cutout punch
A panel-mount DMS-BZL2-C is supplied with each unit.
TECHNICAL NOTES
1. External Brightness Adjustment (Pin 2):
Pin 2 is internally con-
nected to the high impedance input of an operational amplifier that
amplifies the output of the DMS-30DR’s ambient light sensor (ALS)
circuit. The output of this amplifier varies the voltage that drives the
DMS-30DR’s LED display. Leave pin 2 open for standard auto-dim-
ming operation; in this mode, the ALS circuit will automatically adjust
the DMS-30DR’s LED brightness to compensate for changes in ambi-
ent lighting. As the ambient light striking the ALS increases, the LED
display’s brightness will also increase; a decrease in ambient light will
reduce the display’s brightness.
The ALS circuit’s output signal can be overdriven by applying an
externally generated voltage directly to pin 2. External drivers will see
approximately 600Kohms referenced to 5V RETURN. With pin 2 at
+0.7Vdc or below, the DMS-30DR’s LED display is off, and total cur-
rent drain from a nominal +5V supply is approximately 1mA. The LED
display’s brightness will increase from minimum to maximum as the
voltage applied to pin 2 is varied from +0.8V up to +2.5V, respectively.
To enable continuous maximum display brightness, connect pin 2
directly to pin 1 (+5V SUPPLY); in this configuration the total current
drain for the meter will be approximately 200mA.
2. Minimum-Intensity Adjustment Potentiometer:
Users can adjust
the DMS-30DR’s minimum LED brightness to suit their requirements
by adjusting the ¾-turn, rear-mounted intensity adjustment poten-
tiometer. Please note, this potentiometer will have minimal impact
on display brightness in high ambient light environments. See the
Mechanical Specifications section for potentiometer locations.
The intensity adjustment potentiometer is factory preset to its
mid-point position, producing a typical current drain of 7mA. At it’s
minimum and maximum positions, current drain is typically 3mA and
13mA, respectively. As viewed from the rear of the meter, with the
model number label facing up, turning the potentiometer clockwise
increases the display’s intensity.
3. +1.225V REFERENCE OUTPUT (Pin 9):
This pin is the output of the
meter’s precision +1.225V internal reference IC. Pin 9 is referenced
to ANALOG COMMON (pin 10), which in turn sits approximately +2V
above pin 3. Pin 9 should be buffered if it’s used to drive external
loads since sourcing more than 15µA of current can affect both the
Polycarbonate
0.75 ounces (21 grams)
➀
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.
➁
See Technical Notes.
DIGITAL PANEL METERS
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MPM_DMS-30DR_A01
Page 2 of 6
DMS-30DR Series
S U N L I G H T R E A D A B L E , AU T O - D I M M I N G L E D D I S P L AY M E T E R S
accuracy and temperature drift of the meter. A ±1% 1.82K limiting
resistor is connected between the reference IC and pin 9.
4. ANALOG COMMON (Pin 10):
This pin is connected to an internal,
low-noise, “relative” ground. Pin 10 also serves as the internal
ground for the +1.225V reference IC. ANALOG COMMON is used
in certain differential and “floating” measurements as described in
the Applications section of this data sheet, and in DMS Applica-
tion Note 3. For the vast majority of applications, pin 10 should not
be connected to pin 3 (5V RETURN), or to your system’s analog
ground.
5. REFERENCE OUTPUT (Pin 8) and INPUT (Pin 7):
Pin 8 is a preci-
sion reference actively trimmed at the factory. For normal operation,
pin 8 must be tied to pin 7 to achieve all listed accuracy and drift
specifications.
6. Decimal Point Placement:
The location of the decimal point is user
selectable, and the decimal point control pins (DP1-DP3) are active
low functions. Select the desired decimal point by tying the appro-
priate pin (pin 4, 5 or 6) to pin 3 (5V RETURN). Unused decimal
point location pins should be left open. Hard wiring is preferable,
however, you can use logic gates to exercise dynamic control over
the location of the decimal point if the following drive conditions are
met:
Applied “0” Voltage:
+0.4V max
Drive Current*:
6mA max.
* The driving gates must be able to sink this much current (IOL)
with a logic “0” output.
7. Gain-Adjust Potentiometer:
The gain-adjust potentiometer located
on the rear of the meter has approximately ±50 counts (±2.5%)
of adjustment range with a near full-scale input. Since these
meters essentially have no zero/offset errors, a gain adjustment is
effectively an overall accuracy adjustment. Though they may be
performed at any input level except zero, accuracy adjustments are
most effective when performed with half-scale (or higher) positive
input signals.
If a wider adjustment range is required, an external potentiometer
circuit can be configured using the meter’s +1.225V reference
output (pin 9). The circuit shown in Figure 9 provides ±10% range
of adjustment.
8. Soldering Methods:
All models in the DMS-30DR Series easily
withstand most common leaded or lead-free soldering opera-
tions, performed either manually or by wave soldering machines.
However, users should evaluate the effects their particular soldering
techniques may have on the meter’s plastic case and precision
electrical performance. We highly recommend using low residue,
no-clean solders.
9. Suggested Mating Connectors:
Panel mounted:
Connector housing P/N 4320-01069-0
Terminal type:
P/N 4400-01032-0
Crimping tool:
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: P/N 4320-01074-0
APPLICATIONS
DMS-30DR meters are highly versatile devices that can be used in
hundreds of applications. The application circuits chosen for this sec-
tion have historically received many inquiries. Every attempt has been
made to ensure technical accuracy, and all of the following circuits
have been prototyped and tested to ensure functionality. Please keep
in mind, however, that real-world applications are seldom as straight-
forward as the approaches presented here. Most applications have
many more components — and many more connections — than the
illustrations show.
The simplified schematic shown in Figure 1 can be very useful when
debugging a malfunctioning panel meter circuit, particularly if the user
has some knowledge of operational amplifiers (op amps). The meter's
high-impedance input consists of an op amp powered from a ±5Vdc
power supply (the –5V is internally generated). Knowing this, one can
easily see why input signals applied to (–) INPUT LO and (+) INPUT HI
have to be kept within the power supply rails of ±5V. Also note that only
pin 11 has a current-limiting 909kΩ series resistor. High input voltages
that have a common ground with pin 3 (5V RETURN) should only be
applied to pin 11 ((+) INPUT HI) and never to pin 12. In these high-volt-
age cases, pin 12 should always be tied to pin 3 (5V RETURN).
One of the simplified schematic's noteworthy features is that it
shows internal voltage values. It also shows that pin 3 is the meter's
zero-volt reference point — regardless of the type of power or signal
source used. This is an important point to keep in mind when a digital
or analog multimeter is used to make system measurements. The
multimeter's negative lead (usually the black one) must be connected
to pin 3 (5V RETURN).
1. Single-Ended Input Configurations:
True single-ended measure-
ments can be made with any DMS-30DR meter. 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). This will ensure that large LED currents will not
flow in the wiring that connects V
IN
to (–) INPUT LO (pin 12). Ground-
loop currents can cause unstable readings.
½½½½½½½½½½
½
½½½½½½½
½
½
½½
½½
½½½½½½½½½
½
½½
½½½½½½½½½
½
½½½½½½½
½
½½½
½
½½½½½½
½
½½½½½½
½½½½½½½½½
½½½½½½½½½½
½½½½½½½½½½½½½½½½½½
Figure 2. Single-Ended Input Configuration
DIGITAL PANEL METERS
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MPM_DMS-30DR_A01
Page 3 of 6
DMS-30DR Series
S U N L I G H T R E A D A B L E , AU T O - D I M M I N G L E D D I S P L AY M E T E R S
APPLICATIONS
2. Differential Input Configurations:
Differential measurements can be
made with all DMS-30DR meters. Figure 3, though not a practical real-
world application, uses a voltage divider to demonstrate 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. Connecting pin
10 (ANALOG COMMON) or pin 3 (5V RETURN) 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.
½½½½½½½½½½
½½½½½½½
½
½½½½½½½½½½
½½
½½½½½½½½½
½½
½½
½½½½½½
½
½½½
½
½½
½½½½½½½½½
½½
½½
½½½½
½½½½
½
½½
½½½½½½½½½
½
½½½½½½½
½
½½½½½½½
½
½½½½½½
½½
½½
½
½½
½½½½½½½½½
½
½½½½½½
½
½½½½½½½
½½½½½½½½½
½½½½½½½½½½
½½½½½½½½½
½½½½½½½½½½
½
½½½½½½
½
½½½
½½½½½½½½½½½½½½½½½½
Figure 3. Differential Input Configuration
½½½½½½½½½½½½½½½½½½
Figure 5. Floating Input Measurements
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.
50kΩ < R1 + R2 < 10MΩ
R2
x V
IN
= Reading
R1 + R2
½
½½
½½
½½½½½½½½½
½½½½
½½½½
½½½½½½½½½½
½
½½½½½½½
½½
½½½½½½½½
½½
½½½½½½½½½
½
½
½
½½½½½½
½
½½½½½½½
½
½½½½½½
½
½½½
½½½½½½½½½
½½½½½½½½½½
½
½½
½½
½½½½½½½½½
½½½½½½½½½½
½
½½½½½½½
½½½½½½½½½½½½½½½½½½
½½
Figure 6. Floating Input Measurements
(Alternate Configuration)
½
½½
½½½½½½½½½
½
½½½½½½½
½
½½½½½½
½
½½½½½½
½½½½½½½½½
½½½½½½½½½½
½½½½½½½½½½½½½½½½½½
5. Process Control (4-to-20mA) Measurements:
In many common pro-
cess-control applications, a 4-to-20mA current loop is used to transmit
information. Because DMS-30DR meters have such high input imped-
ance, 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)
Figure 4. Input Attenuation Circuit
DIGITAL PANEL METERS
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MPM_DMS-30DR_A01
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DMS-30DR Series
S U N L I G H T R E A D A B L E , AU T O - D I M M I N G L E D D I S P L AY M E T E R S
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
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 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
Shunt
accordingly.
½½
½½½½½½½½½
½
½½½½½½½
represents a basic ammeter connection diagram. A detailed application
note describing digital dc ammeters is available at www.cd4power.com.
½½½½½½½½½½
½
½½½½½½½
½
½½½½
½
½
½½½½½½
½
½½½
½
½½½½½½
½½
½½½½½½½½½
½½
½½½½½½½½½
½½½½½½
½½½½½½½½½½½½½½½½½½½½½½
½½½
½
½
½½½½½
½½½½
½½½½½½½½
½
½½½½½½½½½½
½
½½½½½½½
½½
½½½½½½½½
½½
½½½½½½½½½
½
½½½½½½
½½½
Figure 8. Basic DC Ammeter Circuit
½½½½½½
½½½½½½½½½
6. Digital Ammeter:
Digital ammeters are finding ever-increasing usage
because analog-style ammeters (moving-vane types) now cost roughly
the same as their digital counterparts. Additionally, 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
www.cd4power.com
½
½½
½
½½½½½½
½½
½
½½½½½½
½
½½½½½½
½
½½½
7. External Gain Adjustment:
Connect REFERENCE OUT
(pin 8) to REFERENCE IN (pin 7) for normal, factory calibrated,
operation. Use the +1.225V REFERENCE OUT (pin 9) for applica-
tions needing external gain adjustment. Figure 10 shows the wiring
configuration for each model. Calibration is performed with a precise,
near-full-scale, input voltage.
½½½
½½
½½½½½½½½½
½
½½½½½½
½½
½½½½½½½½½½
½½½½½½½½
½½½½½½½½½½½½½½½½½½
Figure 7. 4-to-20mA Current Loop Operation
½½½½½½½
½½½½½½½½½½
½½½
½½½½½½½½½
½½
½½½½½½½½
½
½½
½½½½½½½½½
½
½½½½½½
½
½½½½½½½½½½
½½½½½½½½½½½
½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½
½½½½½½½½½½½
½½½½½½½½½½
½½½½½½
½½
½½½½½½½½½½½½½½
½½
½½½½½½½½½½½½½½
½½½½½½½½½
Figure 9. External Gain Adjustment
DIGITAL PANEL METERS
MPM_DMS-30DR_A01
Page 5 of 6
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