Figure 1. DMS-30LCDA-4/20 Simplifi ed Schematic
Murata Power Solutions’ new DMS-30LCDA-4/20 Series’ 1.8V nominal loop-drop is the
lowest of any comparably priced, 4-20mA input, 3½-digit process monitors with full-size
LCD displays. This super-low loop-drop guarantees a maximum burden of no more than
100 Ohms! And because it’s loop-powered, all operating power is derived directly from the
loop current itself; no separate power source is required! Their fl oating 2-wire design allows
DMS-30LCDA-4/20 Series process monitors to be connected anywhere in the current loop.
All decimal point and range-change selections are made via an eight-position DIP switch
which features vibration-resistant, gold-plated contacts—there are no cumbersome jumpers
or solder gaps to contend with. Both gain (span) and offset (zero) adjustments are performed
using 20-turn, non-interacting potentiometers. Four different models accommodate unipolar,
bipolar, positive, and inverse display-reading applications. The DMS-30LCDA-4/20 Series’
DIP switch and adjustment potentiometers can accommodate literally hundreds of different
input-current/output-reading combinations.
DMS-30LCDA-4/20 Series’ subminiature package houses a large, 0.40”/10.2mm, high-
contrast LCD display that can be read in virtually all lighting conditions—including full sunlight!
The two connections to the external loop are made via a reliable screw-type terminal block. For
environmentally demanding applications, an optional panel-mount bezel assembly, featuring
screw fasteners and a rubber gasket, provides excellent resistance to dust and moisture. All
these outstanding features combine to make the new DMS-30LCDA-4/20 Series ideal for all
your 4-20mA process-monitoring instrumentation needs.
FEATURES
Super-low loop drop: 1.8V typical, 2.0V max.
Self-powered 2-wire operation; no separate
supply required
Unipolar, Bipolar, Positive, and Inverse Reading Models
Subminiature package; Less than 0.90"
behind-the-panel depth
Large, 0.40"/10.2mm high, sunlight-viewable LCD display
Non-interacting gain (span) and offset (zero)
20-turn potentiometers
DIP-switch selectable range and decimal points
Hundreds of different input-current/readout combinations
Vibration-resistant package; reliable
screw-terminal input connections
3 ½ D I G I T A / D
C O N V E R T E R
D C / D C
C O N V E R T E R
B A N D - G A P
R E F E R E N C E
C I R C U I T
D I P S W I T C H E S
Z E R O
A D J U S T
G A I N
A D J U S T
1 2 3
C U R R E N T T O
V O L T A G E
C O N V E R T E R
+ 5 V 5 V
D P 3D P 2D P 1
R 3 R 7
T B 1
L O O P I N P U T
+
4
O N
O N
O N
58
7654321
D A T A
4 5
www.murata-ps.com
www.murata-ps.com/support
For full details go to
www.murata-ps.com/rohs
DMS-30LCDA-4/20 Series
Loop-Powered, 1.8V Drop, 4-20mA Process
Monitors with Full-Size LCD Displays
MPM_DMS30-LCDA.C01 Page 1 of 6
OPERATING AND SETUP INSTRUCTIONS
Performance/Functional Specifi cations
Typical at TA = +25°C, unless otherwise noted.
➀The DMS-30LCDA-4/20 can withstand continuous overcurrents, including those
resulting from accidental reverse-polarity connections, up to ±40mA without
sustaining any damage.
➁Because Murata Power Solution’s DMS Series loop-powered process monitors
employ active circuitry to convert the loop current into a voltage, their effective
series impedance (loop burden) varies in a manner that maintains the loop volt-
age drop relatively constant over the full 4-to-20mA current range. Listed burden
specifi cation applies at 20mA.
➂When looking up DIP-switch settings in the Tables and the desired display read-
ings can be achieved with either of two different settings, using the higher setting
number will usually result in less sensitive offset (R3) and span (R7) adjustments.
Please keep in mind that the DMS-30LCDA standard meter from which the DMS-
30LCDA-4/20 is derived has an accuracy specifi cation of ±2 counts (max.). Thus,
it may not always be possible to obtain the exact desired display reading.
DMS-30LCDA-4/20S-C** Unipolar reading, loop-powered LCD meter
Bipolar reading, loop-powered LCD meter
Positive reading, loop-powered LCD meter
Inverse reading, loop-powered LCD meter
Bezel assembly
Bezel assembly with sealing gasket
DMS-30LCDA-4/20B-C
DMS-30LCDA-4/20P-C
DMS-30LCDA-4/20I-C
DMS-BZL1-C
DMS-BZL2-C
DMS-30-CP Panel cutout punch
** Replaces obsolete DMS-30LCD-4/20S model
A panel-mount retaining clip is supplied with each model.
-C suffi x indicated RoHS compliance.
The new DMS-30LCDA-4/20S unipolar-reading model has provisions
to accommodate all the display ranges of the obsolete DMS-30LCD-
4/20S. The “Old Display Readings” column in Table 1 is taken directly
from the DMS-30LCD-4/20S datasheet. Table 1 is provided as a guide
for determining equivalent DMS-30LCDA-4/20S DIP-switch settings in
upgrading existing applications.
Applications that had the obsolete DMS-30LCD-4/20S setup for ‘bipolar’
operation should now use the new DMS-30LCDA-4/20S model con-
fi gured per Table 1. Bipolar applications are those where a 4mA input
displays a negative number, a 12mA input displays “000”, and a 20mA
input displays a positive number (for example, “-100”, “000” and “100”).
Applications that had the obsolete DMS-30LCD-4/20S setup for ‘unipo-
lar’ operation should now use the new DMS-30LCDA-4/20S confi gured
per Table 2. Unipolar applications are those where a 4mA input displays
“000” and a 20mA input displays a higher positive number.
Old Display Reading New DMS-30LCDA-4/20S DIP Switch Setting
4mA 20mA SW1 SW2 SW3 SW4 SW5
1. 000 to 100-300 Use Setting in Table 2
2. 000 to 400-600 Use Setting in Table 2
3. 000 to 700-1999 Use Setting in Table 2
4. ±100 On On On On Off
5. ±200 to ±300 Off Off On Off Off
6. ±400 to ±600 On Off Off Off Off
7. ±700 to ±1900 Off Off Off Off On
Table 1. DMS-30LCDA-4/20S DIP Switch Settings for
DMS-30LCD-4/20S Applications
DMS-30LCDA-4/20S (Standard Unipolar-Reading)
The DMS-30LCDA-4/20S’s span and offset circuitry are optimized to
display standard, unipolar readings where a 4mA input always reads
“000” and a 20mA input always displays a higher positive number.
As shipped, the DMS-30LCDA-4/20S is calibrated to read “000” for a
4mA input and “1800” for a 20mA input. These readings are used for
factory test-purposes only. The following worst-case calibration pro-
cedure assumes the DMS-30LCDA-4/20S is completely misadjusted,
i.e., both potentiometers and the DIP switches are randomly set.
The next example below, while specifi cally tailored for the “000” and
“1800” readings just noted, can also be used as a guide when con-
fi guring the DMS-30LCDA-4/20S for other unipolar display readings.
When performing DIP-switch settings, be sure the DIP-switch’s small
actuators are fi rmly engaged in their fully ON or fully OFF positions.
1. Set R7 (span/gain adjust) and R3 (zero/offset adjust) fully clockwise,
roughly 22 turns, and place SW1-SW8 to OFF.
2. Confi gure the meter per DIP-switch setting #1 in Table 2.
3. Apply a precision 4mA input with proper polarity and adjust R3 until
the meter’s display reads “000.”
Current Loop Input Min. Typ. Max. Units
Full Scale Input Range +3.8 – +20.4 mA
Loop Burden – 80 100 Ohms
Voltage Drop – 1.8 2.0 Volts
Overcurrent Protection – – ±40 mA
Performance
Sampling Rate 2.5 reading per second
Accuracy (1 minute warm-up) ±0.05%FS ±1 Count
Temperature Drift – ±0.15 ±0.3 Cnts/°C
Display
Display Type and Size 3½ digit, 0.4"/10.2mm refl
ective LCD
Polarity Indication "–" for negative readings
Overrange Indication "–1_ _ _ " for negative inputs
"1_ _ _ " for positive inputs
Physical/Environmental
Operating Temperature 0– +60 °C
Storage Temperature –20 – +75 °C
Humidity (non-condensing) 0 – 85 °C
Case Material Polycarbonate
Weight 0.75 ounces (21 grams)
Ordering Information
Important Instructions for Users of Obsolete
DMS-30LCD-4/20S Meters
See www.murata-ps.com/dpm-availability for model-specifi c availability.
See www.murata-ps.com/dpm-availability for model-specifi c availability.
www.murata-ps.com/support
DMS-30LCDA-4/20 Series
Loop-Powered, 1.8V Drop, 4-20mA Process
Monitors with Full-Size LCD Displays
MPM_DMS30-LCDA.C01 Page 2 of 6
Table 2. DMS-30LCDA-4/20B (Standard Unipolar) DIP Switch Settings
NOTE: If a display reading other than “000” to “1000” is desired,
refer to DIP-Switch Settings Table 2 for SW1-SW5 settings
1. Desired display readings are:
4mA ="0.00"
20mA = "6.00"
Use DIP-switch setting #3 in Table 2 and enable decimal point DP2
via SW7. Apply 4mA and adjust R3 so the display reads “0.00.” Apply
20mA and adjust R7 so the display reads “6.00.”
2. Desired display readings are:
4mA =" 000"
20mA = "800"
Use DIP-switch setting #2 in Table 2. Apply 4mA and adjust R3 so the
display reads “000.” Apply 20mA and adjust R7 so the display reads
“800.” For these display readings, no decimal points are used. Set
SW6, SW7 and SW8 to OFF.
3. Desired display readings are:
4mA = ".000"
12mA = ".250"
This example is not as straightforward as the previous two. Notice that
12mA is exactly halfway between 4mA and 20mA. If we assume that
the input could go up to 20mA, the display reading would then be: 2 x
.250 or “.500.” From Table 2 we can now select DIP-switch setting #3
and enable DP1 via SW6. Apply 4mA and adjust R3 so the display reads
“.000.” Apply 12mA and adjust R7 so the display reads “.250.”
Examples (DMS-30LCDA-4/20S, Unipolar)
DMS-30LCDA-4/20B (Bipolar-Reading )
The DMS-30LCDA-4/20B’s zero-offset circuit differs from the unipolar
‘S’ model described above in that with the ‘B’ model, a half-scale
12mA input is typically set to display “000.” Therefore, all of the of the
DIP-switch settings in Table 3 assume a reading of “000” is desired
with a half-scale 12mA input. Display readings other than those
shown in Table 3 are possible, contact Murata Power Solutions for
more information.
Desired Display Reading
4mA 20mA SW1 SW2 SW3 SW4 SW5
1. 000 to 1200 to 1999 Off Off Off Off Off
2. 000 to 600 to 1200 On Off Off Off Off
3. 000 to 400 to 600 Off Off On Off Off
4. 000 to 200 to 400 On On On Off Off
5. 000 to 100 to 200 On On On On Off
Table 3. DMS-30LCDA-4/20B (Bipolar) DIP Switch Settings
Desired Display Reading
4mA 12mA 20mA SW1 SW2 SW3 SW4 SW5
1. –600 to –1000 000 600 to 1000 Off Off Off NA NA
2. –350 to –650 000 350 to 650 On Off Off NA NA
3. –250 to –400 000 250 to 400 Off On Off NA NA
4. –150 to –250 000 150 to 250 Off Off On NA NA
5. –100 to –150 000 100 to 150 On On On NA NA
4. Apply a precision 20mA input and adjust R7 until the display reads “1800.”
Repeat steps 3 and 4 to make sure the adjustments do not affect one
another.
5. Select the appropriate decimal point by setting SW6, SW7 or SW8 to ON
(DP1, DP2 or DP3 respectively).
5678
123 4
O N
5678
123 4
O N
5678
123 4
O N
When confi guring the DMS-30LCDA-4/20B for the fi rst time, or when
selecting a new range, set both R3 and R7 fully clockwise (roughly 22 turns)
to their minimum offset/minimum-span positions, respectively. Then select
the desired readings from Table 3 and confi gure DIP-switches SW1, SW2,
and SW3 accordingly. Please note, positions SW4 and SW5 are not used in
bipolar ‘B’ models.
The procedure below illustrates how to calibrate the DMS-30LCDA-4/20B
to its factory-calibrated readings of “-1000” with a 4mA input and “1000”
with a 20mA input. When performing DIP-switch settings, be sure the DIP-
switch’s small actuators are fi rmly engaged in their fully ON or fully OFF
positions.
1. Set both R3 and R7 fully clockwise.
2. Select DIP-switch setting #1 from Table 3.
3. Apply a precision 12mA input and adjust R3 until the meter’s display reads
“000.”
4. Apply a precision 20mA input and adjust R7 until the meter’s display reads
“1000.”
5. Apply a precision 4mA input and the display should read “-1000.” Repeat
steps 3 and 4 to make sure the two adjustments did not affect one another.
1. Desired display readings are:
4mA ="–1.00"
20mA = "1.00"
Use DIP-switch setting #5 in Table 3 and enable decimal point DP2
via SW7. Apply 12mA and adjust R3 so the display reads “0.00.”
Apply 20mA and adjust R7 so the display reads “1.00.” Apply 4mA
and verify that the display reads “-1.00”, readjust R3 and R7 if nec-
essary.
2. Desired display readings are:
4mA =" –450"
20mA = "450"
Use DIP-switch setting #2 in Table 3. Apply 12mA and adjust R3 so
the display reads “000.” Apply 20mA and adjust R7 so the display
reads “450.” Apply 4mA and verify that the display reads “-450.”
Repeat adjustment procedure if necessary. For these display read-
ings, no decimal points are used. Set SW6, SW7and SW8 to OFF.
Examples (DMS-30LCDA-4/20B, Bipolar )
5678
123 4
O N
5678
123 4
O N
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DMS-30LCDA-4/20 Series
Loop-Powered, 1.8V Drop, 4-20mA Process
Monitors with Full-Size LCD Displays
MPM_DMS30-LCDA.C01 Page 3 of 6
3. Desired display readings are:
4mA = "–650"
20mA = "650"
Notice that these readings can be obtained using either DIP-switch
setting #1 or DIP-switch setting #2 in Table 3. In situations like this
where DIP-switch settings overlap, less-sensitive R3/R7 adjustments
can be achieved if the higher DIP-setting # is selected (setting #2
in this example). Apply 12mA and adjust R3 so the display reads
“000.” Apply 20mA and adjust R7 so the display reads “650.” Apply
4mA and verify that the display reads “-650.” Repeat adjustments if
necessary.
DMS-30LCDA-4/20P (Positive-Reading)
The DMS-30LCDA-4/20P’s zero-offset circuit is optimized to produce
positive readings at both 4mA and 20mA input levels. As shown in
Table 4’s fi rst three columns, a 4mA input can be adjusted (using R3,
Zero/Offset Adjust) to display any positive reading between “000”
and “800.” The corresponding 20mA-input reading is then added to
the 4mA offset as a differential whose magnitude is varied by adjust-
ing R7 (Gain/Span Adjust).
The ‘Differential Range’ column in Table 4 lists the nominal dif-
ferential display-readings which can be obtained with R7 at, or very
close to, its full-clockwise, minimum span position. The ‘Differential
Range’ column can be used as a guide when confi guring the meter
for the majority of user applications. Higher differential ranges are
obtainable; however, the use of higher differential readings results
in correspondingly-lower positive readings with 4mA inputs, that
is, R3’s clockwise adjustment-range is reduced. Example #3 below
illustrates this point. Contact Murata Power Solutions if there is any
doubt as to whether or not the DMS-30LCDA-4/20P can be confi g-
ured for your display-reading requirements.
The fi rst step when initially confi guring the DMS-30LCDA-4/20P, or
when selecting a new range, is to set R3 fully counterclockwise and
R7 fully clockwise (roughly 22 turns each) to their minimum offset
and minimum span positions, respectively.
The next step is to calculate the differential display-reading; this is
accomplished by subtracting the desired 4mA display reading from
the desired 20mA display reading, disregarding decimal points. Then,
using the calculated differential display-reading to select the appro-
priate DIP-switch setting # from Table 4, confi gure DIP-switches
SW1, SW2, and SW3 accordingly. Please note, positions SW4 and
SW5 are not used in positive reading ‘P’ models. Also, make certain
that the DIP-switch’s small actuators are fi rmly engaged in their fully
ON or fully OFF positions.
The example below describes how to calibrate the meter for an
application which the DMS-30LCDA-4/20P easily accommodates:
displaying the output of a 4-20mA transmitter, that is, “04.0” with a
4mA input and “20.0” with a 20mA input.
1. Set R3 fully counterclockwise (minimum offset position) and R7 fully
clockwise (minimum differential span position), roughly 22 turns.
2. Subtract 040 from 200 to yield a differential-reading value of 160;
use this value to select DIP-switch setting #5 in Table 4. Enable
decimal point DP3 by placing SW8 to the ON position.
3. Set the transmitter’s output to 4.0mA and carefully adjust R3 clock-
wise until the meter’s display reads “000.”
4. Set the transmitter’s output to 20.0mA and adjust R7 counterclock-
wise until the meter’s display reads “16.0.”
5. Set the transmitter back to 4.0mA and slowly adjust R3 clockwise
until the display reads “04.0.” Reapply 20.0mA and the display
should now read “20.0.” Repeat steps 3, 4, and 5 to make sure the
adjustments did not affect one another.
Table 4. DMS-30LCDA-4/20P (Positive Reading)
DIP Switch Settings
Desired Display Readings
Diff. Range 4mA 20mA SW1 SW2 SW3 SW4 SW5*
1. 800 to 1400 900 1700 Off Off Off NA OFF
2. 500 to 800 850 1350 On Off Off NA OFF
3. 350 to 500 800 1150 Off On Off NA OFF
4. 250 to 350 750 1000 Off Off On NA OFF
5. 150 to 250 750 900 On On On NA OFF
5678
1234
ON
* Setting SW5 to On will increase the differential range.
See example 2 below.
1. Desired display readings are:
4mA ="650"
20mA = "950"
Use DIP-switch setting #4 in Table 4 since subtracting 650 from 950
yields a differential value of 300. Apply 4mA and adjust R3 until the
display reads “000.” Apply 20mA and adjust R7 until the display
reads “300” (the differential value previously calculated). Apply 4mA
and adjust R3 until the display reads “650.” Apply 20mA and verify
that the display reads “950.”
Examples (DMS-30LCDA-4/20P, Positive Reading)
5678
1243
ON
5678
1234
ON
2. Desired display readings are:
4mA =" 4.00"
20mA = "19.99"
This example illustrates the DMS-30LCDA-4/20P’s capability to
display higher differential readings than those indicated in Table
4. This example also illustrates how the DMS-30LCDA-4/20P can
be used to display the output levels of a 4-20mA transmitter with
higher precision (0.01mA versus 0.1mA) than the example previ-
ously described.
Subtracting 400 from 1999 yields a differential of 1599, a value
not listed in Table 4. However, use DIP-switch setting #1 in Table
4 and enable SW5 since this setting has the highest overall offset/
span adjustment capabilities. Enable DP2 via SW7, then apply 4mA
and adjust R3 so the display reads “0.00.” Apply 20mA and adjust
R7 so the display reads “15.99.” Apply 4mA and adjust R3 until the
display reads “4.00.” Apply 20mA and check to see that the display
reads “19.99” or just overranges (“1—”). Repeat adjustment
procedure if necessary.
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DMS-30LCDA-4/20 Series
Loop-Powered, 1.8V Drop, 4-20mA Process
Monitors with Full-Size LCD Displays
MPM_DMS30-LCDA.C01 Page 4 of 6
DMS-30LCDA-4/20I (Inverse Reading)
The DMS-30LCDA-4/20I is designed to accommodate applications
where an increasing loop current produces a decreasing display
reading. That is, as the loop current is increased from 4mA to 20mA,
the display will read a user determined full-scale positive number
at 4mA and then decrease to “000” at 20mA. The ‘4/20I’ model is
essentially a ‘-4/20S’ model operating in reverse. Table 5 and the
two examples that follow describe the operation of this model in
greater detail.
The fi rst step when confi guring the DMS-30LCDA-4/20I for the fi rst
time, or when changing to a different range, is to set both R3 and
R7 to their full clockwise positions, roughly 22 turns. Next, using the
desired display readings, select the appropriate DIP-switch setting
number from Table 5.
Examples (DMS-30LCDA-4/20I, Inverse Reading)
1. Desired display readings are:
4mA = “6.00”
20mA = “0.00”
Use DIP-switch setting #3 in Table 5 and enable decimal point DP2
via SW7. Apply 20mA and adjust R3 so the display reads “0.00.”
Apply 4mA and adjust R7 so the display reads “6.00.”
2. Desired display readings are:
4mA = “800”
20mA = “000”
Use DIP-switch setting #2 in Table 5. Apply 20mA and adjust R3 so
the display reads “000.” Apply 4mA and adjust R7 so the display
reads “800.” For these display readings, no decimal points are used.
Set SW6, SW7 and SW8 to OFF.
Table 5. DMS-30LCDA-4/20I (Inverse Reading) DIP Switch Settings
Desired Display Reading
4mA 20mA SW1 SW2 SW3 SW4 SW5
1. 1999 to 1300 000 Off Off Off Off NA
2. 1300 to 850 000 On Off Off Off NA
3. 850 to 550 000 Off On Off Off NA
4. 550 to 350 000 Off Off On Off NA
5. 350 to 200 000 On On On Off NA
6. 200 to 130 000 On On On On NA
Table 6. Decimal Point Selections (All Models)
To turn on a decimal point, place its respective DIP switch to the fully ON position.
SW6 SW7 SW8
DP1 DP2 DP3
5678
1243
ON
5678
1234
ON
MECHANICAL DIMENSIONS: Inches (mm)
TOLERANCES: 2 PL DEC ±0.02 (±0.51)
3 PL DEC ±0.010 (±0.254)
WIRE SIZE: 18 to 26 AWG
(Solid or stranded)
STRIPPING LENGTH: 0.20" (5.08mm)
MECHANICAL SPECIFICATIONS
DIP
Switches
Gain
Adjust
Zero
Adjust
+–
Loop
Input DP2
(SW7)
DP3
(SW8)
DP1
(SW6)
Back View
Front View
1
R3
Zero
Adjust
R7
Gain
Adjust
5678
1234
ON
+–
TB1
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DMS-30LCDA-4/20 Series
Loop-Powered, 1.8V Drop, 4-20mA Process
Monitors with Full-Size LCD Displays
MPM_DMS30-LCDA.C01 Page 5 of 6
#2-56 INSERT
0.156 (3.96) DEEP
FRONT VIEW
1.270
(32.26)
0.187
(4.75)
OPTIONAL BEZEL (DMS-BZL1 and DMS-BZL2)
2.35 (59.69)
2.118 (53.80)
0.093 (2.362) DIAMETER (4 REQUIRED)
ONLY WHEN USING OPTIONAL BEZEL ASSEMBLY
RECOMMENDED DRILL AND PANEL CUTOUT DIMENSIONS
INTERNAL CORNER RADII:
0.032 (0.81) MAX.
1.07
(27.18) 0.878
(22.30)
0.096
(2.44)
0.116
(2.95)
2.55 (64.77)
PANEL CUTOUT
PANEL
BEZEL
BEZEL INSTALLATION AND RECOMMENDED DRILL AND PANEL CUTOUT
RETAINING CLIP INSTALLATION
PANEL
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Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other
technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply
the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifi cations are subject to change without
notice. © 2015 Murata Power Solutions, Inc.
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfi eld, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
This product is subject to the following operating requirements
and the Life and Safety Critical Application Sales Policy:
Refer to: http://www.murata-ps.com/requirements/
DMS-30LCDA-4/20 Series
Loop-Powered, 1.8V Drop, 4-20mA Process
Monitors with Full-Size LCD Displays
MPM_DMS30-LCDA.C01 Page 6 of 6
