Fluctuating ADC Reading for 4-20mA Pressure transducer input

[Wawa]

Use a 51ohm resistor (standard 1% E24 value) instead of a 250ohm resistor.
And Arduino's internal 1.1volt Aref instead ot the potentially unstable default Aref.
You might also want to add protection and filtering (see diagram).
Leo..

const int sensorPin = A0;
int sensorValue;


void setup() {
  Serial.begin(9600);
  analogReference(INTERNAL);
}


void loop() {
  sensorValue = analogRead(sensorPin);

  Serial.print("Reading: ");
  Serial.println(sensorValue);

  delay(1000);
}