DMS-30DR Delta Electronics, DMS-30DR Datasheet - Page 5

• Manufacturer Part Number: DMS-30DR
• Description: Digit Panel Meters
• Manufacturer: Delta Electronics

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APPLICATIONS
6. Digital Ammeter: Digital ammeters are finding ever-increasing usage
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DMS-30DR Series
Example: For a meter with a 2V full scale input (1.999 full
scale reading) and a desired display reading of
"1000" (with an input of 20mA), V
To calibrate the circuit of Figure 7, perform the following:
1. With 4mA applied, adjust the 50kΩ potentiometer (R2) to
2. With 20mA applied, adjust the gain-adjust potentiometer on
because analog-style ammeters (moving-vane types) now cost roughly
the same as their digital counterparts. Additionally, analog ammeters
are not nearly as rugged as modern digital panel voltmeters. Figure 9
illustrates a typical ammeter application. The circuit uses a ±200mV
input meter — the preferred range for most ammeters — to measure
the voltage developed across a 0.1Ω current shunt. The circuit shown
display a reading of "000" (assuming that is the desired
reading).
the back of the meter to display a reading of "1000". For
different full scale readings, alter the value of R
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R
R
Shunt
Shunt
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Figure 7. 4-to-20mA Current Loop Operation
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= 1.000V/(0.020 – 0.004)A
= 1.000V/0.016A = 62.5 Ohms
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Fsr
= 1.000 Volts
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Shunt
S U N L I G H T R E A D A B L E , A U T O - D I M M I N G L E D D I S P L A Y M E T E R S
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accordingly.
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7. External Gain Adjustment: Connect REFERENCE OUT
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(pin 8) to REFERENCE IN (pin 7) for normal, factory calibrated,
operation. Use the +1.225V REFERENCE OUT (pin 9) for applica-
tions needing external gain adjustment. Figure 10 shows the wiring
configuration for each model. Calibration is performed with a precise,
near-full-scale, input voltage.
represents a basic ammeter connection diagram. A detailed application
note describing digital dc ammeters is available at www.cd4power.com.
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Figure 8. Basic DC Ammeter Circuit
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Figure 9. External Gain Adjustment
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D I G I T A L P A N E L M E T E R S
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MPM_DMS-30DR_A01
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