I think my converter is broken.
I tried to adjust it for both 0 kPa (0 psi) and 50 psi .
It maxes out at in terms of its overall range of around 2.8 volts.
At lowest ZERO span setting voltage read through multimeter is:
-2.392/2.385 volts
If I adjust the potentiometer such that the read out is 0 volts at 0 psi, then the half way point of 50 psi should read 2.5 volts but that is not the case even after adjustment ( I was assuming it might have to read 1.25 V based on the instructions below in bullet point 4)
I have found the voltage range does not extend beyond approx. 2.8 volts from what I last remember.
The potentiometers start to make a clicking sound when they are maxed out.
The instructions they have are confusing:
https://bit.ly/2CwncAK
Instructions for use:
- Module according to the definition of wiring, power supply voltage 7-36V (if the output to 10V, the supply voltage must be greater than 12V)
- After power-up, the D2 indicator should be on, otherwise check the line connection. Board with reverse protection, reverse does not burn.
- When the current input is the minimum (0mA or 4mA), adjust the ZERO potentiometer so that the VOUT output is the minimum (0.0V or other voltage)
- When the current input is at maximum (20mA), adjust the SPAN potentiometer so that the VOUT output is the maximum (3.3V or 5V or 10V, the output can be as low as 2.5V when the input is 4-20ma)
I have both jumpers on for 0-5.0V range.
According to your needs, through the jumper cap to select the appropriate range:
4--20ma: 0-2.5V range: J1 1,2 feet short, 3,4 feet shorted
0 - 3.3V range: J1 1,2 feet off, 3,4 feet off
0 - 5.0V range: J1 1,2 feet short, 3,4 feet shorted
0--10.0V range: J1 1,2 feet short, 3,4 feet off
I tried to use code without smoothing and I am still getting inconsistent results
/************************************************************
Pressure Sensor Key Parameters
- Part No.: Omegadyne PX-409
- Sensing range: 0 - 0.689476 MPa
- Input Voltage: 24 VDC
- Input Current: 4-20 mA
- Output Voltage: 0.0 - 5.0 VDC
(Linearly corresponding to 0 - 0.689476 MPa)
- Accuracy: ±0.08% BSL Includes Linearity, Hysteresis,and Repeatability
Pressure Sensor Calibration
Calibration: connect the 3 pin wire to the Arduino UNO (VCC, GND and Signal)
without connecting the sensor to the water pipe and run the program
for once. Mark down the LOWEST voltage value through the serial
monitor and revise the "OffSet" value to complete the calibration.
After the calibration the sensor is ready for measuring!
4-20 mA to 0-5 V Signal generator potentiometers settings:
-2.392/2.385 volts read as lowest possible ZERO span setting
**************************************************************/
int inputPin = A5;
float Voltage = 0;
const float OffSet = 0.09286412239074;
float Pressure;
void setup()
{
Serial.begin(9600); // open serial port, set the baud rate to 9600 bps
Serial.println("/** Water pressure sensor measurement **/");
}
void loop()
{
Serial.print("Raw Value = " ); // shows pre-scaled value
Serial.print(analogRead(inputPin));
Serial.println();
Voltage = (analogRead(inputPin) / 1023.0) * 5; // Gets you V
Serial.print("Voltage = "); // shows the voltage measured
Serial.print(Voltage, 14); // the '3' after voltage allows you to display 3 digits after decimal point
Serial.println();
Pressure = (Voltage - OffSet) * 137.8952; // Calculate pressure --> 689.476kPa / 5V = 137.8952 kPa/V
Serial.print("Pressure = ");
Serial.print(Pressure, 14);
Serial.println(" KPa");
Serial.println();
delay(4000);
}