Gravity: Throw-in Type Liquid Level Transmitter - pressure sensor

[cristma762]

hello everyone, right now im working with my sensor ( Gravity: Throw-in Type Liquid Level Transmitter), you all could find information on the next link ( micro:bit breadboard shield for learning programming - DFRobot ) so, i am have trouble with the results, i used the electronic distribution that said on the page aun used the code that said on the page but i have wrong results, pleas ewho can i help me? my result with this senosr are like 4 meters but i put the sensor in 10 cm of water column

more information about the sensor on the netx page

Gravity: Industrial Stainless Steel Submersible Pressure Level Sensor(0~5m)

the code used was :
/***********************************************************
DFRobot Gravity: Analog Current to Voltage Converter(For 4~20mA Application)
SKU:SEN0262

GNU Lesser General Public License.
See http://www.gnu.org/licenses/ for details.
All above must be included in any redistribution
****************************************************/

#define ANALOG_PIN A1
#define RANGE 5000 // Depth measuring range 5000mm (for water)
#define CURRENT_INIT 4.00 // Current @ 0mm (uint: mA)
#define DENSITY_WATER 1 // Pure water density normalized to 1
#define DENSITY_GASOLINE 0.74 // Gasoline density
#define PRINT_INTERVAL 1000

int16_t dataVoltage;
float dataCurrent, depth; //unit:mA
unsigned long timepoint_measure;

void setup()
{
Serial.begin(9600);
pinMode(ANALOG_PIN, INPUT);
timepoint_measure = millis();
}

void loop()
{
if (millis() - timepoint_measure > PRINT_INTERVAL) {
timepoint_measure = millis();

dataVoltage = analogRead(ANALOG_PIN);
dataCurrent = dataVoltage / 120.0; //Sense Resistor:120ohm
depth = (dataCurrent - CURRENT_INIT) * (RANGE/ DENSITY_WATER / 16.0); //Calculate depth from current readings

if (depth < 0) depth = 0.0;

//Serial print results
Serial.print("depth:");
Serial.print(depth);
Serial.println("mm");
}
}

[JCA34F]

Which Arduino?
Post a drawing of exactly how the sensor, load resistor and Arduino are connected together and powered.

[jremington]

Please read and follow the directions in the "How to use this forum" post. Edit your post to add code tags.

[cristma95]

arduino uno
powered 12v
i used the next ink

i use the next code

/***********************************************************
  DFRobot Gravity: Analog Current to Voltage Converter(For 4~20mA Application)
  SKU:SEN0262

  GNU Lesser General Public License.
  See <http://www.gnu.org/licenses/> for details.
  All above must be included in any redistribution
 ****************************************************/

#define ANALOG_PIN A1
#define RANGE 5000 // Depth measuring range 5000mm (for water)
#define CURRENT_INIT 4.00 // Current @ 0mm (uint: mA)
#define DENSITY_WATER 1  // Pure water density normalized to 1
#define DENSITY_GASOLINE 0.74  // Gasoline density
#define PRINT_INTERVAL 1000

int16_t dataVoltage;
float dataCurrent, depth; //unit:mA
unsigned long timepoint_measure;

void setup()
{
  Serial.begin(9600);
  pinMode(ANALOG_PIN, INPUT);
  timepoint_measure = millis();
}

void loop()
{
  if (millis() - timepoint_measure > PRINT_INTERVAL) {
    timepoint_measure = millis();

    dataVoltage = analogRead(ANALOG_PIN);
    dataCurrent = dataVoltage / 120.0; //Sense Resistor:120ohm
    depth = (dataCurrent - CURRENT_INIT) * (RANGE/ DENSITY_WATER / 16.0); //Calculate depth from current readings

    if (depth < 0) depth = 0.0;

    //Serial print results
    Serial.print("depth:");
    Serial.print(depth);
    Serial.println("mm");
  }
}

[Wawa]

That current/voltage module setup has a resolution of about 400 levels with the potentially unstable default Aref of the Uno. And I think the code is mostly nonsense. 400 levels over 5meters is readout steps of 1.25cm at best.

A single ~51ohm resistor, and maybe some surrounding protection parts, would have given you about 800 levels, with a more stable supply-independent readout.
A resistor with ADS1115 module would have given you several thousand levels.
Many examples on this site. Enter "4-20" in the search field on top of this page.
Leo..

[MarkT]

Surely that line:

    dataVoltage = analogRead(ANALOG_PIN);

needs to be

    dataVoltage = 5.0 * analogRead(ANALOG_PIN) / 1024;

So its an actual voltage, not a number between 0 and 1023...

[Wawa]

But the Arduino (Uno) does not reliable read/return a voltage with default Aref.
The A/D returns a ratio of it's own supply, which could be 4.8 or 5.1volt.

If you want to read a voltage you must use a fixed/stable Aref, like the internal 1.1volt Aref.
Or link the Aref to the more stable 3.3volt supply. DFRobot should know better.
Leo..