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DMS-40PC-4/20S
4½ Digit, 4-20mA Input, LED Display Meters
MPM_DMS-40PC-420.E01 Page 2 of 6
TECHNICAL NOTES
Performance/Functional Specifi cations
Typical at TA = +25°C, unless otherwise noted. (1) Full Scale Input: The DIP Switch settings display readings in Table 1
can typically be obtained with transmitters having a low-level output
of 3.7 to 4.3mA and a full-scale output of 19.4 to 20.4mA. When
using transmitters whose outputs fall outside these ranges, try using
the next highest DIP switch setting if the desired reading is too low,
or the next lowest setting if the desired display reading is too high.
Example number 2 illustrates this point.
Please keep in mind that the DMS-40PC meter from which the
DMS-40PC-4/20S is derived has an accuracy specifi cation of ±3
counts (max.); thus, it may not always be possible to obtain the exact
desired display readings. A change of ±1 count is defi ned as the
right-hand most digit (the"ones" LED) going up or down by one.
Other display readings not shown in Table 1 are obtainable. For
example, some negative readings with a 4mA input are possible.
Consult Murata Power Solutions for more information regarding
display readings not shown in the table.
(2) Loop Impedance/Drop: The maximum loop impedance and the
maximum loop voltage-drop are both specifi ed with DIP switch set-
ting #20 enabled. The maximum loop voltage drop is specifi ed with a
20.0mA input current.
(3) Temperature Drift: Temperature drift of zero and temperature drift
of gain are both specifi ed with the meter confi gured for range #20
with 4mA adjusted (using R3) to read "0000" ±1 count, and 20mA
adjusted (using R7) to read "19000" ±2 counts.
The temperature drift of gain is proportional to the full scale range
being used. It is typically less pronounced at the lower range set-
tings, that is, if the observed gain drift of a particular meter is +12
counts when reading "19000" on range #20 at 40°C, the same
meter will most likely have a drift of only +6 counts when reading
"9000" on range #12 at 40°C.
The normally very accurate autozeroing feature of the DMS-40PC-
4/20S's internal analog-to-digital converter (A/D) is not a factor in
determining the meter's zero-reading stability over temperature due
to the fact that an offset voltage is applied to the A/D's LO input.
This offset voltage is used to null the voltage developed with a 4ma
input. To function properly, the autozeroing feature found in most
digital panel meters requires both A/D inputs to remain at zero volts
with varying temperature. The meter's zero-reading stability over
its specifi ed operating temperature is affected by the drift of three
terms: the voltage developed by the meter's offset circuitry; the volt-
age developed across the meter's input resistor(s) with a 4mA input;
and the stability of the applied 4mA input signal itself. In the lower
DIP switch settings ( ranges #1-4), the meter's parasitic etch and
switch interconnect resistances also contribute a small error.
The meter's performance with regards to span stability over tem-
perature is affected by the drift of the meter's gain circuitry and the
drift of the input resistor(s). To counter these drifts in applications
requiring the utmost in temperature stability, where possible, the
meter should be calibrated at its anticipated operating temperature.
For these applications, use of the DMS-40PC-4/20S-5RL model is
highly recommended because of its inherently lower power con-
sumption and self-heating.
DMS-40PC-4/20S-5RS-C +5V supply, standard-intensity red LEDs
DMS-40PC-4/20S-5GS-C +5V supply, standard-intensity green LEDs
DMS-40PC-4/20S-5RL-C +5V supply, low-power red LEDs
DMS-40PC-4/20S-5RH-C +5V supply, high-intensity red LEDs
DMS-40PC-4/20S-24RL-C +7.5V to +32V supply, low-power red LEDs
DMS-40PC-4/20S-24RS-I-C +24V isolated supply, standard-intensity red LEDs
DMS-40PC-4/20S-24RH-I-C +24V isolated supply, high-intensity red LEDs
DMS-40PC-4/20S-24GS-I-C +24V isolated supply, standard-intensity green LEDs
DMS-BZL1-C Panel-mount bezel assembly
DMS-BZL2-C Panel-mount bezel assembly with sealing gasket
DMS-30-CP Panel cutout punch
A panel-mount retaining clip is supplied with each meter.
Current Loop Input Min. Typ. Max. Units
Full Scale Input Range (1) +3.7 – +20.4 mA
Loop Burden (2) 12 – 103 Ohms
Voltage Drop (2) – – 2.1 Volts
Overcurrent Protection – – ±40 mA
Performance
Sampling Rate 2.5 reading per second
Accuracy (1 minute warm-up) To ±0.01%FS ±2 Count
Temperature Drift of Span (3) – ±0.3 ±0.6 Cnts/°C
Temperature Drift of Zero (3) – ±0.2 ±0.5 Cnts/°C
Power Supply Requirements (4)
DMS-40PC-4/20S-5RS +4.75 to +5.25Vdc at 140mA max.
DMS-40PC-4/20S-5GS +4.75 to +5.25Vdc at 140mA max.
DMS-40PC-4/20S-5RH +4.75 to +5.25Vdc at 140mA max.
DMS-40PC-4/20S-RL +4.75 to +5.25Vdc at 50mA max.
DMS-40PC-4/20S-24RL +7.5 to +32Vdc at 50mA max.
DMS-40PC-4/20S-24XX-I (models) +21.6 to +26.4Vdc at 60mA max.
Display
Display Type and Size 4½ digit, 0.52"/13.2mm high LED
Polarity Indication "–" for negative readings
Overrange Indication "–1_ _ _ " for negative inputs
"1_ _ _ " for positive inputs
Physical/Environmental
Operating Temperature 0 – +50 °C
Storage Temperature –40 – +75 °C
Humidity (non-condensing) 0 – 95 °C
Case Material Polycarbonate
Weight 0.1 ounces (28 grams)
Ordering Information