Datel DMS-20LCD-4/20 Series User manual

DATEL, Inc., Mansfield, MA 02048 (USA) •Tel:[phone] Fax:[phone] • E–mail:[email protected] • Internet:www.datel.com
DMS-20LCD-4/20 Series
Figure 1. DMS-20LCD-4/20 Series Simplified Schematic
Features
®®
TheDMS-20LCD-4/20Seriesproducesthelowestloopvoltage-dropofanycompa-
rablypriced,4-20mAinput,3½digitLCD-displayprocessmonitors:1.8Vtypical,2.0V
max.Thissuper-lowdropmeansitsnominalloopresistance(burden)islessthan100
Ohms!Alloperatingpowerisderivedsolelyfromthe4-20mAloopcurrent—noseparate
powersourceisrequired!Thesimple2-wirehookupallowstheDMS-20LCD-4/20Series
tobeconnected
anywhere intheloop
Alldecimal-pointandrange-changeselectionsaremadeviaasix-positionDIP
switchfeaturingvibration-resistant,gold-platedcontacts—therearenojumpersorsolder
gapstoever open or close. Both gain(span)andoffset(zero)adjustments are per-
formed with precision, 20-turnpotentiometers.Threedifferentmodelsareavailablefor
unipolar,bipolar,andpositivedisplayreadingapplications.TheDMS-20LCD-4/20’s DIP
switchandadjustmentpotentiometerscanaccommodateliterallyhundreds of different
input-current/output-readingcombinations.And,connectionstothecurrent loop are made
viaareliable,two-position,screw-typeterminalblock.
TheDMS-20LCD-4/20Series’subminiaturepackagehousesa large, 0.37"/9.4mm
highdigits,LCDdisplaythatcanbe read in virtuallyalllightingconditions—includingdirect
sunlight.An optional bezel assembly,featuringscrewfastenersandarubberseal,
simplifiespanelmountingandprovidesexcellentresistanceto environmental dust and
moisture.Alltheseoutstandingfeaturescombineto make the DMS-20LCD-4/20 Series
theperfectmetersforOEM4-20mAcurrent-loopprocessmonitoringinstrumentation.
••
••
• Super-low loop drop: 1.8V typical, 2.0V max.
••
••
• Self-powered, no separate supply required
••
••
• Unipolar, Bipolar, and Positive Reading
Models
••
••
• Subminiature package—Less than 0.90”
behind-the-panel depth
••
••
• Large, 0.37"/9.4mm 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/readout
combinations
••
••
• Vibration-resistant package; reliable
screw-terminal input connections
DATA
3½DIGIT A/D
CONVERTER
DC/DC
CONVERTER
BAND-GAP
REFERENCE
CIRCUIT
DIP SWITCHES
ZERO
ADJUST GAIN
ADJUST
123
CURRENT TO
VOLTAGE
CONVERTER
+5V –5V
DP3DP2DP1
R3 R7
12
TB1
LOOP INPUT
561
1
12
2
23456
3
34 456
ON
ON
ON
–+
4-20mA Input Loop-Powered
Ultra-Low 1.8V Loop Drop, 3½Digit
LCD-Display Process Monitors
Actual Size
www.datel.com

2
DATEL, Inc., Mansfield, MA 02048 (USA) •Tel:[phone] Fax:[phone] • E–mail:[email protected] • Internet:www.datel.com
Operating and Setup Instructions
Performance/Functional Specifications
Typical at TA= +25°C, unless otherwise noted.
DMS-20LCD-4/20 3½DIGIT, LCD DISPLAY, 4-20mA LOOP-POWERED METERS
➀ TheDMS-20LCD-4/20,usinganyofthe DIP-switch settings described above,can
withstandovercurrents,includingthose resulting fromaccidentalreverse-polarity
connections,upto±40mA without sustaininganydamage.
➁ BecauseDATEL'sDMS-4/20loop-poweredmetersemploy activecircuitry to convert
the loop current into a voltage, the meters' effective series impedance varies in a
manner that maintains the loop voltage drop constant over the full 4-to-20mA current
range.Listedimpedance specification appliesat20mA.
➂ WhenlookingupDIP-switch settings intheTablesandthedesireddisplayreadings
can be achieved with either of two different settings, using the higher setting # will
producelesssensitiveoffset (R3) and span (R7)adjustments.Pleasekeep in mind
that the DMS-20LCD standard meter (from which the DMS-20LCD-4/20 is derived)
hasanaccuracyspecificationof±2counts (max.).Thus,itmay not alwaysbepossible
toobtaintheexact desired display reading.
1. Set R7 (full scale span/gain adjust) and R3 (zero/offset adjust) fully
clockwise, roughly 22 turns, and place SW1-SW6 to OFF.
2. SelectDIPswitch setting#2.
3. Apply a precision 4mA input, with proper polarity, 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".Repeat steps 3 and 4 to make sure the adjustments do
not affect one another.
5. Select the appropriate decimal point by setting SW4, SW5 or SW6 to
ON (DP3, DP2 or DP1 respectively).
NOTE: If a display reading other than "000" to "1000" is desired,
refer to DIP–Switch SettingsTable 1 for SW1–SW3 settings.
Current Loop Input Min. Typ. Max. Units
Full Scale Input Range ➀ +3.8 –– +20.4 mA
Input Impedance ➁ –– 80 100 Ω
Voltage Drop ➁ –– 1.8 2.0 Volts
Overcurrent Protection ➀ –– –– ±40 mA
Performance
Sampling Rate 2.5 readings per second
Accuracy (1 minute warm–up) ±0.05%FS ±1 Count
Temperature Drift (0 to +60°C) –– ±0.15 ±0.3 Cnts/°C
Display
Display Type and Size 3½digit LCD, 0.37"/9.4mm
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 –– 95 %
Case Material Polycarbonate
Weight 0.6 ounces (17 grams)
Display Reading SW1 SW2 SW3
4mA 20mA
1. 000 to 1050-1999 Off Off Off
2. 000 to 650-1350 On Off Off
3. 000 to 450-800 Off On Off
4. 000 to 300-500 Off Off On
5. 000 to 200-300 On On On
Table 1. DMS-20LCD-4/20S (Unipolar Model)
DIP-Switch Settings
DMS-20LCD-4/20S Unipolar reading, loop-powered LCD meter
DMS-20LCD-4/20B Bipolar reading, loop-powered LCD meter
DMS-20LCD-4/20P Positive reading, loop-powered LCD meter
DMS-BZL3 Bezel assembly
DMS-BZL4 Bezel assembly with sealing gasket
DMS-20-CP Panel cutout punch
Ordering Information
Apanel-mountretainingclip is supplied witheachmodel.
1. Desired display readings are:
4mA="0.00"
20mA = "6.00"
Use DIP-switch setting #3 in Table 1 and enable decimal point DP2
via SW5. 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 inTable 1.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
SW4, SW5 and SW6 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".FromTable 1 we can now select DIP-switch
setting #4 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-20LCD-4/20S-Unipolar Model)
ON
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DMS-20LCD-4/20S (Unipolar Reading Model)
As shipped, the DMS-20LCD-4/20S is factory calibrated to read "000"
for a 4mA input and "1000" for a 20mA input.The following worst-case
procedure assumes the DMS-20LCD-4/20S is completely mis-adjusted, i.e.,
bothpotentiometersand the DIPswitchesarerandomly set. Whenperforming
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Orderon-lineatwww.datel.com
DIP-switch settings, be sure the DIP switch's small actuators are firmly
engagedin their fully-ONorfully-OFF positions.

3
DATEL, Inc., Mansfield, MA 02048 (USA) •Tel:[phone] Fax:[phone] • E–mail:[email protected] • Internet:www.datel.com
3½DIGIT, LCD DISPLAY, 4-20mA LOOP-POWERED METERS DMS-20LCD-4/20
DMS–20LCD–4/20B (Bipolar Reading Model)
The DMS-20LCD-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
normally set to display "000".Therefore, all of the of the DIP-switch settings
in Table 2 assume a reading of "000" is desired with a 12mA input. Display
readings other than those shown in Table 2 are possible, contact DATEL for
more information.
When configuring the DMS-20LCD-4/20B for the first 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 2 and configure DIP-switches SW1, SW2, and
SW3 accordingly.
The procedure below illustrates how to calibrate the DMS-20LCD-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 firmly 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 2.
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.
Examples (DMS-20LCD-4/20B-Bipolar Model)
1. Desired display readings are:
4mA= "–1.00"
20mA= "1.00"
Use DIP-switch setting #5 in Table 2 and enable decimal point DP2 via
SW5. 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 necessary.
2. Desired display readings are:
4mA = "–450"
20mA = "450"
Use DIP-switch setting #2 in Table 2.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 readings, no
decimal points are used.Set SW4, SW5 and SW6 to OFF.
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 inTable 2.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 adjustment procedure if necessary.
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Display Reading SW1 SW2 SW3
4mA 12mA 20mA
1. –600 to –1000 000 600 to 1000 Off Off Off
2. –350 to –650 000 350 to 650 On Off Off
3. –250 to –400 000 250 to 400 Off On Off
4. –150 to –250 000 150 to 250 Off Off On
5. –100 to –150 000 100 to 150 On On On
Table 2. DMS-20LCD-4/20B (Bipolar Model)
DIP-Switch Settings
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DMS-20LCD-4/20P (Positive Reading Model)
The DMS-20LCD-4/20P’s Zero-Offset circuit is optimized to produce
positive readings at both 4mA and 20mA input levels. As shown in Table 3’s
first three columns, a 4mA input can be typically 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 adjusting R7 (Gain/Span Adjust).
The ‘Differential Range’column in Table 3 lists the nominal differential
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 configuring 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 concept.Please contact DATEL if
there is any doubt as to whether or not the DMS-20LCD-4/20P can be
configured for your display readings requirements.
The first step when configuring the DMS-20LCD-4/20P for the first time, or
when selecting a new range, is to set R3 fully counterclockwise and R7 fully
clockwise (roughly 22 turns) to their minimum offset/minimum span
positions, respectively.
The next step is to calculate the required display differential-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 appropriate DIP-switch
setting # from Table 3, configure DIP-switches SW1, SW2, and SW3
accordingly.Make certain that the DIP-switch’s small actuators are firmly
engaged in their fully-ON or fully-OFF positions.
The procedure below describes how to calibrate the meter for an applica-
tion which the DMS-20LCD-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.

DMS-20LCD-4/20 3½DIGIT, LCD DISPLAY, 4-20mA LOOP-POWERED METERS
4
DATEL, Inc., Mansfield, MA 02048 (USA) •Tel:[phone] Fax:[phone] • E–mail:[email protected] • Internet:www.datel.com
Table 4. Decimal Point Settings
Figure 2. Typical DMS-20LCD-4/20 Connection Diagram
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 value of 160; use
this value to select DIP-switch setting #5 inTable 3. Enable decimal
point DP3 by placing SW4 to the ON position.
3. Set the transmitter’s output to 4.0mA and carefully adjust R3 clockwise
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.
Examples (DMS-20LCD-4/20P-Positive Model)
1. Desired display readings are:
4mA = “650”
20mA = “950”
Use DIP-switch setting #4 in Table 3 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”.
2. Desired display readings are:
4mA = “4.00”
20mA = “19.99”
This example illustrates the DMS-20LCD-4/20P’s capability to display
higher differential readings than those indicated in Table 3.This example
also illustrates how the DMS-20LCD-4/20P can be used to display the
output levels of a 4-20mA loop transmitter with higher precision (0.01mA
versus 0.1mA) than described above.
Subtracting 400 from 1999 yields a differential of 1599, a value not listed in
Table 3.However, use DIP-switch setting #1 in Table 3 since this setting
has the highest overall offset/span adjustment capabilities. Enable DP2 via
SW5 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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Table 3. DMS-20LCD-4/20P (Positive Reading Model) DIP-
Switch Settings
Differential Range 4mA Input 20mA Input
Display Reading SW1 SW2 SW3
➀ Shown for illustrative purposes only, may not be present in all applications
➀
SW4 SW5 SW6
DP3 DP2 DP1
1. 800-1400 900 1700 Off Off Off
2. 500-800 850 1350 On Off Off
3. 350-500 800 1150 Off On Off
4. 250-350 750 1000 Off Off On
5. 150-250 750 900 On On On
A/D
PROGRAMMABLE LOGIC CONTROLLER
TRANSMITTER &
SIGNAL CONDITIONER
TRANSDUCER
INPUT
+
––
DMS-20LCD-4/20
+–
Vsig
+
–
GAIN
ZERO
+24V
4-20mA
4-20mA
+
–
+24Vdc
SUPPLY
+
(TB1-1) R7
R3
(TB1-2)

DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151
Tel: [phone] [phone] Fax: [phone]
Internet: www.datel.com Email: [email protected]
Data sheet fax back: [phone]
DATEL(UK)LTD.Tadley, England Tel:[phone]
DATEL S.A.R.L.Montigny Le Bretonneux,France Tel:[phone]
DATELGmbHMünchen,Germany Tel:[phone]
DATEL KKTokyo,Japan Tel:[phone], Osaka Tel:[phone]
DATELmakesnorepresentationthattheuse ofitsproductsinthecircuitsdescribedherein,ortheuseofother technicalinformationcontainedherein,willnotinfringeuponexistingorfuturepatentrights.The descriptionscontainedhereindonotimplythe granting
oflicensestomake,use,orsellequipmentconstructed inaccordancetherewith.Specificationsare subjecttochangewithoutnotice.TheDATELlogois a registeredDATEL,Inc.trademark.
ISO 9001
ISO 9001
REGISTERED
®®
DMS-20LCD-4/20 3½DIGIT, LCD DISPLAY, 4-20mA LOOP-POWERED METERS
Mechanical Specifications
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)
#2-56 INSERT
0.156 (3.96) DEEP
FRONT VIEW
1.280
(32.51)
0.187
(4.75)
OPTIONAL BEZEL (DMS-BZL3 and DMS-BZL4)
RECOMMENDED DRILL AND PANEL CUTOUT DIMENSIONS
1.826 (46.38)
0.838
(21.29)
1.336 (33.93)
1.626 (41.30)
1.07
(27.18)
INTERNAL CORNER RADII:
0.032 (0.81) MAX.
0.145
(3.68)
0.093 (2.362) DIAMETER (4 REQUIRED)
ONLY WHEN USING OPTIONAL BEZEL ASSEMBLY
0.116
(2.95)
®®
BEZEL INSTALLATION
BEZEL
PANE
L
®®
RETAINING CLIP INSTALLATION
PANE
L
Back View FrontView
DIP
Switches
Gain/Span
Adjust
Zero/Offset
Adjust
Loop
Input
DP2
(SW5) DP3 (SW4)
DP1
(SW6)
0.80
(20.3)
0.040
(1.02)
1.30
(33.0)
1.38
(35.1) 0.88
(22.4)
0.90
(22.9)
MADE IN USA
DMS-20LCD-4/20
®®
R3
R7
12 1
1
12
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3456
ON
ON
+–
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DS-0400A 6/99