Fluctuating ADC Reading for 4-20mA Pressure transducer input

[BHARGAV SHANKHALPARA]

Hello...

I am working on one project of water pressure measurement, in which i used pressure transducer which gives me output between 4-20mA Current form.

I am using one 250 ohm resistance to convert current into voltage, and than i give this voltage to ADC of arduino UNO channel 0 (A0).

ADC reading is continuously fluctuating up to 10 decimal numbers.

I have also check by connecting multi-meter and measure sensor current reading, for particular pressure. but current reading is stable (even not fluctuate 1 or 2 points.)

also i have checked voltage value after 250 Ohms +Ve and ground. converted voltage is also showing very stable.

but why ADC reading is fluctuating..?

i am using arduino uno, i doesn't have any changes in AREF, AVCC etc...

please suggest effective solution,

Thank in advance.

My code is as follow
************************************

const int analogInPin = A0; // Analog input pin that the potentiometer is attached to

int sensorValue = 0; // value read from the pot

void setup()
{
// initialize serial communications at 9600 bps:
Serial.begin(9600);
}



void loop()
{

// read the analog in value:
sensorValue = analogRead(analogInPin);


// print the results to the Serial Monitor:
Serial.print("Reading: ");
Serial.println(sensorValue);

delay(1000);
}

 

[(*steve*)]

Your measurements with a multimeter may not show rapid changes. Have you tried looking at the voltage using an oscilloscope or even your multimeter on an AC range?

What effect sites placing a capacitor (say 1uF) across the resistor have?

If you connect the ADC input to a voltage divider across the power supply, do you get a more constant reading?