The DMS-20PC-4/20 Series are the world's fi rst loop-powered digital panel meters
with a large, easy-to-read, bright red, LED display. All operating power is derived
directly from the loop current itself—no external power supply is required! The large,
0.37"/9.4mm digits exhibit uniform intensity over the entire 4-20mA operating range.
Additionally, the total maximum loop voltage drop is only 5V! Users no longer have to
settle for diffi cult-to-read LCD displays in loop-powered applications.
Both gain (span) and offset (zero) adjustments are performed with on-board, precision, 20-turn potentiometers. All decimal-point and range-change selections are
made on a six-position DIP switch featuring vibration-resistant, gold-plated contacts.
Unlike competitive meters, there are no jumpers or solder gaps to open or close.
Connections to the current loop are made via a reliable, two-position, screw-type
terminal block.
The DMS-20PC-4/20's DIP switch and adjustment potentiometers accommodate
hundreds of different input-current/output-reading combinations. This versatility practically eliminates the need to order more costly, long-lead-time, factory-customized "specials" in applications in which several different-range meters are required. An optional
bezel assembly, featuring screw fasteners and a rubber seal, simplifi es panel mounting
and provides excellent resistance to environmental dust and moisture. All these outstanding features combine to make the DMS-20PC-4/20 Series the perfect meters for
prototype and OEM 4-20mA current-loop instrumentation.
3½ DIGIT A/D
CONVERTER
3
2
R3R7
GAIN
ZERO
ADJUST
ADJUST
BAND-GAP
REFERENCE
CIRCUIT
+5V–5V
DC/DC
CONVERTER
Figure 1. DMS-20PC-4/ 20 Series Simplifi ed Schematic
Full Scale Input Range ➀ +4 –– +20 mA
Input Impedance ➁ –– 250 –– Ω
Voltage Drop ➁ –– 4.5 5.0 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 3½ digit, red LED, 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 –40 –– +75 °C
Humidity (Non–condensing) 0 –– 95 %
Case Material Polycarbonate
Weight 0.6 ounces (17 grams)
➀ The DMS-20PC-4/20, using any of the DIP-switch settings described above, can
withstand overcurrents, including those resulting from accidental reverse-polarity
connections, up to ±40mA without sustaining any damage.
➁ Because DATEL's DMS-4/20 loop-powered meters employ active circuitry to con-
vert 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. Listed impedance specifi cation applies at 20mA.
➂ When looking up DIP-switch settings in the Tables and the desired display readings
can be achieved with either of two different settings, using the higher setting # will
produce less sensitive offset (R3) and span (R7) adjustments. Please keep in mind
that the DMS-20PC standard meter (from which the DMS-20PC-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.
Ordering Information
DMS-20PC-4/20S Unipolar reading, loop-powered LED meter
DMS-20PC-4/20B Bipolar reading, loop-powered LED meter
DMS-20PC-4/20P Positive reading, loop-powered LED meter
DMS-PS4-CM +24V/0.45A AC/DC power supply module
DATEL 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. The DATEL logo is a registered DATEL, Inc. trademark.
DS-0353D 05/03
DATEL China Shanghai, China Tel: 011-86-51317131
E-mail: [email protected]
Page 6
DMS-30PC-4/20S
3½ DIGIT, 4-20mA INPUT, LED DISPLAY METERS
Performance/Functional Specifications
Typical at TA = +25°C, unless otherwise noted.
Current Loop InputMin.Typ.Max.Units
Full Scale Input Range+3.5--+22mA
Input Impedance--100--
Ω
Voltage Drop----2.0Volts
Overcurrent Protection----±40mA
Performance
Sampling Rate2.5 readings per second
Accuracy (1 minute warm-up)±0.05%FS ±1 Count
Temperature Drift (0 to +60°C)--±0.15±0.3Cnts/°C
Power Supply Requirements
➀➀
➀
➀➀
DMS-30PC-4/20S-5RS+4.75 to +5.25Vdc at 225mA max.
DMS-30PC-4/20S-5GS+4.75 to +5.25Vdc at 225mA max.
DMS-30PC-4/20S-5RH+4.75 to +5.25Vdc at 225mA max.
DMS-30PC-4/20S-5RL+4.75 to +5.25Vdc at 20mA max.
DMS-30PC-4/20S-24RL+7.5 to +32Vdc at 30mA max.
DMS-30PC-4/20S-24XX-I Models+21.6 to +26.4Vdc at 60mA max.
Display
Display Type and Size 3½ digit LED, 0.56"/14.2mm high
Polarity Indication"–" for negative readings
Overrange Indication"–1_ _ _" for negative inputs
Input Grounding: Except for the "-I"suffix models which feature isolated
current loop inputs, all other DMS-30PC-4/20S meters are supplied with
their 4-20mA negative-input terminals (TB1-2, "-") internally connected to
their power supply ground terminal (TB2-2, “-V”). This single-ended input
configuration is compatible with most grounded-referenced 4-20mA
transmitters.
Applications in which the DMS-30PC-4/20S and its associated 4-20mA
transmitter are connected to a common ground and the transmitter drives two or
more loads (for example, the meter in series with a PLC) must have the meter
connected as the first device in the current loop, that is, closest to the system
ground (see Figure 2). If this is not possible and/or the meter must be connected
in the middle of the current loop, then'-I' suffix models must be used to provide
the required isolation between the meter’s current loop input and the power
supply ground ("-V"). See Figures 2, 3, 4, and 5 for typical loop connections.
➁
When looking up DIP-switch settings in the Table and the desired display
readings happen to fall between two switch settings, try performing the
adjustments with both settings to determine which one offers the better
settability. Please keep in mind that the DMS-30PC meter (from which
the DMS-30PC-4/20S is derived) has an accuracy specification of ±2
counts (max.). Thus, it may not always be possible to obtain the exact
desired display reading.
Order on-line at www.datel.com
Ordering Information
DMS-30PC-4/20S-5RS+5V supply, standard-intensity red LED's
DMS-30PC-4/20S-5GS+5V supply, standard-intensity green LED's
DMS-30PC-4/20S-5RL+5V supply, low-power red LED's
DMS-30PC-4/20S-5RH+5V supply, high-intensity red LED's
DMS-30PC-4/20S-24RL+7.5V to +32V supply, low-power red LED's
DMS-30PC-4/20S-24RS-I+24V isolated supply, standard-intensity
DMS-30PC-4/20S-24RH-I+24V isolated supply, high-intensity red LED’s
DMS-30PC-4/20S-24BS-I+24V isolated supply, high-intensity blue LED’s
DMS-30PC-4/20S-24GS-I+24V isolated supply, standard-intensity
DMS-PS4-CM+24V/0.45A AC/DC power supply module
DMS-PS7-CM+24V/0.7A AC/DC power supply module
A panel-mount retaining clip is supplied with each model.
Operating and Setup Instructions
As shipped, the DMS-30PC-4/20S is factory calibrated to read "000"
for a 4mA input and "1999" for a 20mA input. The following worst-case
procedure assumes the DMS-30PC-4/20S is completely mis-adjusted, i.e.,
both potentiometers and the DIP switches are randomly set.
1. Set R7 (gain/span adjust) and R3 (zero/offset adjust) fully clockwise,
roughly 20 turns, and place SW1-SW8 to OFF (down position).
2. Set SW1 to ON (up position). See DIP switch setting #3.
3. Apply a precision 4mA input, with proper polarity, and adjust R3 until
the meter's display reads "000".
4. Apply a precision 20mA and adjust R7 until the display reads "1999".
Repeat 3 and 4 to make sure adjustments do not affect one another.
5. If desired, select the appropriate decimal point by setting either SW5,
SW6 or SW7 to ON (DP1, DP2 or DP3 respectively).
NOTE: If a display reading other than "000" to "1999" is desired,
refer to the DIP-Switch Settings Table for SW1-SW4 settings.
Examples
1. Desired display readings are:
4mA ="0.00"
20mA = "2.00"
Use DIP-switch setting #1 and enable decimal point DP2 via SW6.
Apply 4mA and adjust R3 so the display reads "0.00". Apply 20mA and
adjust R7 so the display reads "2.00".