www.murata-ps.com
DCA5-20PC Series
50mV & 100mV Input, LED-Display, Subminiature DC Ammeters
FEATURES
Scales and displays the output of 5A to
2000A, 50mV & 100mV shunts
Completely self-contained – no additional
components required
Wide power supply inputs: 5 to 40Vdc for
12V/24V/28V applications
option for telecom supplies
48V
Isolated-supply models for high-side shunts
Large, easy-to-read LED display with 0.37”
(9.4mm) high digits
Available in red, blue or green LED displays
Subminiature 1.38” x 0.88” package with
screw-style terminal blocks
Factory calibrated to ±0.1% accuracy;
Reverse-polarity protection
Over 50 models available
Digital upgrade for analog meters
Murata Power Solutions’ new DCA5-20PC Series dc ammeters are specifically designed to dis-
play the output of all popular 50mV and 100mV dc-shunts. 25 input ranges provide for precision
measurement of dc currents from 1.000A to 2000A. With the exception of an external shunt,
the unit is 100% self-contained – no calibration or user-supplied components are required.
Available LED-display colors include brilliant blue, bright green, and standard red. Three power
supply options accommodate all popular dc-supply voltages from 5V to 75Vdc, making these
ammeters perfect for automotive, industrial, telecom, and marine applications!
DCA5-20PC Series ammeters are housed in 1.38” x 0.88” (35mm x 22mm) rugged pack-
ages that feature a large, 0.37”/9.4mm high, LED display. However, display visibility is not com-
promised in any way: the display can be easily read at distances up to 15 feet (5 meters). All
input and power supply connections are made by way of two screw-style terminal blocks. For
added flexibility, computer-style jumpers are provided for range-specific decimal point assign-
ments. And, to ensure trouble free installation, all models include reverse-polarity protected
power supply inputs.
Two input configurations are offered: grounded shunt (“low-side”), 5-40V-powered, red,
green or blue LED models for cost-sensitive applications, and 8-36V isolated-supply models
that accept high-side or floating shunts. Isolated-supply models are also available in a choice
of red, green, or blue LEDs. Since many dc ammeters are used in battery backup applications,
power consumption for 8-36V models is typically 1 Watt, and 75mW for 5-40V models.
Miniature size, wide supply inputs, and no-hassles installation make DCA5-20PC Series
ammeters the ideal choice for all your 50 and 100mV shunt ammeter-applications.
LED DISPLAY
+
INPUT
AMPLIFIER
+5V
CAL
A/D
CONVERTER
–5V
POWER
CONVERTER
*
–
**
1
2
TB1
SIGNAL
GROUND
1
1
2
2
TB2
POWER
GROUND
–IN
+IN
+V
–V (GND)
*
Not included on all models
**
Open on isolated power models
EXTERNAL
50 or 100mV SHUNT
EXTERNAL DC SUPPLY
+
–
For full details go to
www.murata-ps.com/rohs
Figure 1. DCA5-20PC Series Simplified Schematic
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MPM_DCA5-20PC.C01
Page 1 of 6
DCA5-20PC Series
50mV & 100mV Input, LED-Display, Subminiature DC Ammeters
Performance/Functional Specifications
Typical at T
A
= +25°C, unless otherwise noted.
Input (TB1)
➀
Full Scale Input
➀
Overvoltage Rating
➁
Input Impedance
Min.
49.5
±400
–
Typ.
50
–
1K
Max.
50.5
–
–
Units
mV
mV
Ohms
Ordering Information
DCA5-20PC -
x
- DC1 - R L - C
Add
-C
for RoHS
LED Color:
BL
= Low-Power Blue
BS
= Super Blue
Power Supply:
GS
= Standard Green
DC1
= +5-40Vdc, non-isolated power
PGL
= Low-Power Green
(available with -RL, -BL, or -PGL LEDs)
RL
= Low-Power Red
DC4
= +8-36Vdc, isolated power
(available with -RL, -BS, or -GS LEDs)
Input Range:
Use with these 50mV shunts*
1
5A
50A 500A
2
1A
10A 100A 1000A
3
30A 300A
4
75A 750A
5
15A 150A 1500A
6
2A
20A 200A 2000A
7
25A 250A
8
400A
9
600A
10
80A 800A
11
1200A
or
with these 100mV shunts*
10A 100A 1000A
2A
20A 200A 2000A
60A 600A
15A 150A 1500A
—
—
5A
50A 500A
80A 800A
120A 1200A
—
—
Shunt Input to Power Supply Isolation
➂
DCA-20PC-X-DC4
models only
Performance
Sampling Rate
Accuracy
Zero-Current Reading
➃
Temperature Drift
(0 = +60°C)
Power Supply Voltage (TB2)
DCA-20PC-X-DC1-XX
DCA-20PC-X-DC4-XX
Power Supply Current
➄
DCA-20PC-X-DC1-XX (@ 5-40V)
DCA-20PC-X-DC4-XX (@ 8V)
DCA-20PC-X-DC4-XX (@ 36V)
TB1 and TB2 Terminal Blocks
Wire Size
Insulation Strip Length
Screw Tightening Torque
Rated Current
16-22AWG, solid or stranded
0.250 inches
2.2 lb·in (0.25 N·m) ±20%
20A with 12AWG solid copper wire;
15A with 14AWG solid or stranded
copper wire
–
–
–
10
100
25
15
150
40
mAdc
mAdc
mAdc
+5.0
+8
–
–
+40
+36
Vdc
Vdc
“–001”
–
2.5 reading per second
±0.15%FS
“000”
±0.2
“001”
±0.4
Counts
Cnts/°C
500
–
–
Vdc
*With respective decimal point user enabled. See technical note 7.
See
www.murata-ps.com/dpm-availability
for model-specific availability.
Accessories:
DMS-20-CP
Shunt Model
3020-01097-0
3020-01107-0
3020-01098-0
3020-01096-0
3020-01099-0
3020-01108-0
3020-01100-0
3020-01101-0
3020-01102-0
3020-01103-0
3020-01104-0
3020-01105-0
3020-01106-0
Panel Cutout Punch
Rating
5A/50mV
10A/100mV
20A/50mV
50A/50mV
100A/50mV
100A/100mV
150A/50mV
200A/50mV
300A/50mV
500A/50mV
800A/50mV
1000A/50mV
1200A/50mV
Display
Display Type and Size
Overrange Indication
Display Reading/Decimal Point
Physical/Environmental
Operating Temperature
Storage Temperature
Humidity (non-condensing)
Case Material
Dimensions
Weight
0
–20
0
–
–
–
+60
+75
85
°C
°C
%
3½ digit, 0.37"/9.4mm high red, blue or
green LED
"–1_ _ _" for negative Vin
"1_ _ _" for positive Vin
Model dependent
Use with
DCA5-20PC-1
DCA5-20PC-1
DCA5-20PC-6
DCA5-20PC-1
DCA5-20PC-2
DCA5-20PC-1
DCA5-20PC-5
DCA5-20PC-6
DCA5-20PC-3
DCA5-20PC-1
DCA5-20PC-10
DCA5-20PC-2
DCA5-20PC-11
A DMS-BZL4-C bezel assembly with sealing gasket is supplied with each ammeter.
Polycarbonate
1.38"W x 0.88" x 1.0" nominal
0.6 ounces (17 grams)
➀
A full-scale input voltage of 50.00mV is used to calibrate all models for their designated
measurement range. The ammeter’s rear calibration potentiometer compensates for
full-scale input variations up to ±1% (49.5 to 50.5mV).
Measuring positive and negative currents (bipolar operation):
In applications
where both positive and negative currents must be measured, Murata Power Solu-
tions recommends using ‘-DC4’ 8-36V isolated supply models. Negative current
flow is denoted by the illumination of the display’s negative (–) sign; the absence of
a negative sign implies positive current flow. Contact MPS if you have any questions
regarding bipolar operation of DCA5-20PC ammeters.
➁
On non-isolated ‘-DC1’ models, continuous application of single-ended ±400mV
inputs will not damage the ammeter. Single-ended inputs are defined as those
whose TB1-1 (–IN) potential is within ±0.1V of the potential on TB2-2 (-V). For
all models, the application of short-duration (5 seconds max.) ±1V inputs will not
damage the ammeter.
➂
Breakdown (isolation) voltage applies only to ‘-DC4’ isolated-power models.
Breakdown voltage is tested with TB1-1 tied to TB1-2 (–IN shorted to +IN) and
TB2-1 tied to TB2-2 (+V shorted to -V). 500Vdc is then applied between the
two shorted terminal-block pairs; the max. allowable leakage current is 5uA.
➃
Zero reading is measured with TB1-1 (–IN) shorted to TB1-2 (+IN).
➄
Power supply currents noted are measured with the 50mV shunt input (TB1) at
zero volts (display reads “000”) and one decimal point enabled.
➅
Each model’s full-scale display reading with a 50.0mV input is designated by the
first X in the DCA5-20PC-X-XXX model number structure. Decimal point selection
(DP1, DP2, DP3, or none) is performed by the user to suit desired amperage range.
Input ranges -1, -2, -3, -4, -7, -8 and -9 can accommodate 100mV shunts. For these
ranges, the indicated 50mV reading is doubled when a 100mV input is applied.
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MPM_DCA5-20PC.C01
Page 2 of 6
DCA5-20PC Series
50mV & 100mV Input, LED-Display, Subminiature DC Ammeters
TECHNICAL NOTES
To ensure safe and reliable operation, DCA5-20PC dc ammeters must
only be installed and serviced by qualified technical personnel. DC
ammeter applications can expose a user to potentially lethal currents and
voltages. Power and signal connections must be made with all associ-
ated power sources de-energized. Contact Murata Power Solutions if you
have any questions regarding the installation or operation of any of our
digital instruments.
1. Calibration:
DCA5-20PC ammeters are designed to operate with 50mV
and 100mV dc shunts whose rated accuracy is ±0.25%, or better. The
output of less accurate shunts may fall outside the ammeter’s ±1% calibra-
tion adjustment range. Under normal indoor operating conditions, periodic
recalibration of DCA5-20PC ammeters is not necessary. The calibration
potentiometer, located on the back of the ammeter, is a ¾ turn type; do not
force its adjustment screw past the two end stops.
If user calibration is deemed necessary, it must be performed by qualified
personnel. Calibration is performed by applying a precision 50.00mVdc or
100mVdc (model specific, see ordering guide) signal to TB1, observing
correct polarity. Then, using an insulated slotted tool, adjust the calibration
potentiometer until the correct display reading is achieved. Contact MPS if
additional information is required regarding calibration or setup of DCA5-
20PC ammeters.
2. Wiring and Fusing:
Power supply (TB2) and input (TB1) wiring must
be rated for the electrical and environmental conditions under which the
ammeters will be operated. They must also comply with any regulatory or
application-mandated requirements pertaining to the user’s installation. Con-
nections to DCA5-20PC ammeters must be made with all power sources
de-energized. Refer to the Functional Specifications section for TB1 and
TB2 wire gauge information.
DCA5-20PC ammeters’ shunt (TB1) and power supply inputs (TB2) are not
internally fused. Therefore, the supply wires connected to the meter and the
load should be fused according to the maximum current rating (or lower)
of the wire gauge used, in accordance with applicable regulatory codes.
Insulation should be stripped to within +/-10% of the stated dimensions. All
wires must be inserted into the terminal block openings such that the screw
terminal does not pinch any insulation. TB2 is to be used solely for power-
ing the meter’s internal circuitry; it must not be used to supply current to an
external load or auxiliary device.
3. Terminal Block Torque Ratings:
It is important to tighten TB1’s and TB2’s
screw-terminals to their rated torque specifications of 3.6 pound-inches (0.4Nm).
Proper tightening will minimize losses and ensure reliable operation.
4. High-Side versus Low-Side Shunts:
Incorrect shunt connections are
one of the most common problems encountered when applying digital
dc-ammeters. Incorrect shunt connections can cause permanent damage to
the ammeter and/or its associated equipment.
Low-Side Shunts:
Applications that employ a single power supply to power both
the load and the ammeter, and the external shunt is located in the negative side
of the supply (commonly referred to as “low side” or “grounded shunt”) should
use ‘-DC1’ non-isolated power DCA5-20PC Series ammeters. Figures 2, 3, and 4
depict typical low-side shunt connections.
High-Side Shunts:
‘-DC4’ isolated-power ammeters must be used in all
applications that employ a single power supply to power both the load and
the ammeter
and
the shunt is located in the high side (positive terminal) of
the supply. Figures 5 and 6 depict typical high-side shunt connections. As
shown in Figure 6, isolated-power models can also be used in applications
1 TB1
DCA5-20PC-X-DC1-XX
1
J3
1
1
2
J1 J2
1
2
3
CAL
2
J3 MUST BE INSTALLED
(FACTORY SETTING) FOR
5-40Vdc SUPPLIES
J1 AND J2 POSITIONS
DEPEND ON INPUT RANGE
2
1 TB2 2
–IN
SHUNT MUST
BE IN LOW SIDE
+IN
+V
+
–V
DC SUPPLY
5-40Vdc
–
LOAD
50mV SHUNT
LOAD CURRENT
POWER
GROUND
(0Vdc)
Figure 2. Low-Side Shunt Connections for "-DC1"
5-40Vdc Non-Isolated Supply Models
DCA5-20PC-X-DC1-XX
1
J3
1
1
2
J1 J2
1
2
3
CAL
2
REMOVE J3
FOR 36-75Vdc
SUPPLIES
1 TB1
2
1 TB2 2
–IN
SHUNT MUST
BE IN LOW SIDE
+IN
LOAD
+V
+
–V
DC SUPPLY
36-75Vdc
–
50mV SHUNT
LOAD CURRENT
POWER
GROUND
(0Vdc)
Figure 3. Low-Side Shunt Connections for "-DC1" Models Modified for
36-75Vdc Non-Isolated Power (See Technical Note 5)
where one supply powers the ammeter and a second supply powers the
load, but the two supply grounds cannot be tied together. ‘-DC4’ isolated-
supply models include a built-in dc/dc converter to provide a minimum of
500Vdc isolation between the shunt (TB1) and power supply inputs (TB2).
5. Operation With 36 to 75Vdc Power:
As shipped, all ‘-DC1’ models’ rated
operating supply range is +5 to +40Vdc. However, ‘-DC1’ models can be
user configured for 36 to 75Vdc operation by removing (opening) jumper
J3. Please note that this user modification can only be performed on ‘-DC1
power models. Also, all ‘-DC1’ models – including those that have been
modified for 36-75Vdc operation – can only be connected in low-side,
grounded-shunt applications. See Figure 3 for detailed wiring information.
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MPM_DCA5-20PC.C01
Page 3 of 6
DCA5-20PC Series
50mV & 100mV Input, LED-Display, Subminiature DC Ammeters
APPLICATIONS
Any reconfiguration of J3 must be made prior to connecting the power
supply and shunt to the ammeter.
6. Replacing Analog Panel Meters:
DCA5-20PC ammeters can be
used as replacements for analog panel meters that are driven by
50 or 100mV shunts, if a suitable dc voltage is available for powering the
ammeter. In retrofit applications, it is extremely important to determine the
shunt’s electrical configuration (i.e., high or low side). If any doubt exists as
to the shunt’s location, use only ‘-DC4’ isolated-supply models. Rewiring
must be performed with all power sources de-energized.
DCA5-20PC-X-DC1-XX
1
7. Decimal Point Selection:
As shown in the Ordering Information guide, DCA5-
20PC ammeters are multiple input-range devices. For example, with a 50mV
input, DCA5-20PC-1-DC1 models can be configured to display “5.00”, “50.0, or
“500” Amps by simply removing or relocating decimal-point-selector jumper J2
(see Figure 7). Decimal points serve as placeholders only; they have no affect
on displayed accuracy or resolution. If jumper J2 is not available, solder gaps
SG1, SG2, or SG3 can be used to select DP1 (“1.XXX”), DP2 (“1X.XX”), or
DP3 (“1XX.X”), respectively.
1
J3 J1 J2
J3
1
1
2
J1 J2
1
2
3
1
1
2
3
CAL
J3 MUST BE INSTALLED
(FACTORY SETTING) FOR
5-40Vdc SUPPLIES
J1 AND J2 POSITIONS
DEPEND ON INPUT RANGE
2
CAL
2
1 TB1
2
1 TB2 2
1 TB1
2
M1
1 TB2 2
–IN
+IN
+V
–V
SHUNT CAN BE IN
LOW OR HIGH SIDE
–IN
+IN
+V
+
–V
–
DC SUPPLY #1
8-36Vdc
DISCHARGE
–
12 V
BATTERY
+
50mV SHUNT
+
DC SUPPLY
#2
50mV SHUNT
CHARGE
LOAD
–
SOLAR
PANELS
+
LOAD CURRENT
–
–
LOADS
+
Figure 4. Typical Low-Side Shunt Connections for "-DC1" Models
Measuring a Battery’s Charge/Discharge Current
1
Figure 6. Using "-DC4" Isolated-Power Models to Maintain Isolation
Between Two Power Supplies
ALL MODELS
1
J2 CONFIGURATION
1
2
3
DP2 OFF
DP3 OFF
J3 J1 J2
1
1
2
3
J3
1
1
2
J1 J2
1
2
3
SG3
SG2
SG1
CAL
2
CAL
2
1
2
3
DP2 ON
(1X.XX)
1
2
3
DP3 ON
(1XX.X)
1 TB1
2
M1
1 TB2 2
1 TB1
2
1 TB2 2
J1 CONFIGURATION
1
2
DP1 OFF
–IN
+IN
+V
+
–V
DC SUPPLY
8-36Vdc
1
2
DP1 ON
(1.XXX)
–
Figure 7. Decimal Point Selection Using J2 and J1
(Applies to All Models)
POWER
GROUND
(0Vdc)
50mV SHUNT
LOAD CURRENT
LOAD
Figure 5. High-Side Shunt Connections for "-DC4"
8-36Vdc Isolated-Power Models
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MPM_DCA5-20PC.C01
Page 4 of 6
DCA5-20PC Series
50mV & 100mV Input, LED-Display, Subminiature DC Ammeters
APPLICATIONS
8. Operation With 100mV Shunts:
Many DCA5-20PC Series ammeters
can also operate with 100mV shunts. This is due to the fact that when
they are driven by a 100mV input, the display readings are double
those of a 50mV input. However, a 50mV shunt cannot be used in
a 100mV application because its maximum current rating will be
exceeded.
For our customer’s convenience, Murata Power Solutions offers a
series of 50mV and 100mV chassis-mount dc shunts that can be used
with DCA5-20PC ammeters. Part numbers for accessory shunts can
be found in the Ordering Information section. A data sheet describing
these shunts is available at www.murata-ps.com.
Table 1 indicates the obtainable readings of the seven DCA5-20PC
models that can be operated with 100mV shunts. Be sure to enable the
correct decimal point (see decimal point selection instructions).
9. Noisy Power Supplies:
Some power supplies contain high-frequency
switching devices that may conduct and/or radiate significant noise
onto the low-level 50/100mV shunt signal. Even though the DCA5-
20PC incorporates built-in filtering at its shunt input, some portion of
this noise may be amplified and subsequently measured by the DCA5-
20PC’s sensitive circuitry. The amplified noise introduces errors that are
particularly noticeable at zero load current (i.e., the ammeter may not
display a relatively steady “000” reading).
Connecting an external, unpolarized capacitor across TB1’s “+” and
“–” inputs, and/or across the shunt’s 50mV output terminals, can help
reduce noise-related display errors. In certain situations, the use of
twisted pair or shield wiring may be required. As a general rule, avoid
using excessively long leads between the ammeter and the shunt.
Table 1. 100mV Shunt Readings
*
Model
100mV Shunt Readings
DCA5-20PC-1
DCA5-20PC-2
DCA5-20PC-3
DCA5-20PC-4
DCA5-20PC-7
DCA5-20PC-8
DCA5-20PC-9
10.00A/100.0A/1000A
1.999A/19.99A/199.9A/1999A
60.0A/600A
150.0A/1500A
50.0A/500A
800A
1200A
*
With respective decimal point enabled
PANEL INSTALLATION
All connections and modifications must be made after the ammeter
is securely attached to the panel, with all load and supply voltages
de-energized (off).
The installed wire-positions should be such that minimal forces are applied
to TB1, TB2, and the ammeter itself. In high-vibration environments, the
use of wiring strain-reliefs is recommended.
To insure a secure panel-mount installation, MPS recommends using the
DMS-BZL4-C (with sealing gasket) bezel assembly supplied with each
ammeter. See the Mechanical Specifications section for detailed panel
cutout and ammeter dimensions.
Following the four-step sequence shown in Figure 8 below, being careful
not to apply excessive force or twisting motions, insert the ammeter into
the panel opening. When using the DMS-BZL4-C’s sealing gasket, make
sure it is positioned between the ammeter’s flange and the panel’s front
surface. Be sure to use and securely tighten all four screws supplied with
the bezel assembly.
Step 1.
Step 2.
Step 3.
Step 4.
1
3
2
4
Figure 8. Panel Installation
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MPM_DCA5-20PC.C01
Page 5 of 6
Power technology
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