Sensor

Other Hardware Sensors
1

I have a pressure sensor. This is KELLER PA-21G 0-30 BAR.

http://impexron-ltd.com/en/product-keller_pa21g030bar_cena_bulgaria-501601

I cannot find the library to create code.

I hope everybody help me.
Thank you

2

How is it powered? How many wires? What type of output signal? Post a manufacturer's data sheet.

3

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4

That sensor was only for OEM and it is obsolete now.
PDF: https://www.elit.se/media/k2/attachments/keller_serie_21g.pdf
There are only two versions, 2-wire 5-20mA and 3-wire 5V with ratiometric output.

5

Thanks for your attention.
It has 2-wire.
It has:
"PA-21G/0...30 bar
Range: 0...30 bar
Output: 4...20mA
WH OUT/GND: BN:+Vcc"

I need your help.
Thank you!!!

6

What voltage are you using for the sensor? Looks like the MINIMUM is 8 volts, MAXIMUM is 28.
Which Arduino?

7

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8

Thank you everybody!!!
Sorry, I don''t have any information about the Voltage.
Thank you for your ideas.

9

The voltage is what you have to supply yourself to feed the sensor. The current the sensor draws, ranges from 4-20mA depending on the measured signal. This method is often used in industry. The supply and the returning signal run through the same simple two wire cable which can be km's in length.

250 Ohm * 20 mA is 5V. If your board is a 3.3V you must apply a smaller resistor. The measurement is probably more accurate if you use the internal voltage reference of the board.
see here
If the reference is 1.1V the resistor must be 55 ohm.

10

This is the common diagram for 1.1volt Aref, with some extra protection.
51ohm is a standard E24 value.
Leo..

702×227 9.05 KB

11

Can you please say, how to measure current using ACS712, across the running PWM generated pulsed DC motor. I am using this code. the frequency of the PWM is 20KHz.
Please help me in details,

#define VIN A3 // define the Arduino pin A0 as voltage input (V in)

const float VCC = 5.0; // supply voltage is from 4.5 to 5.5V. Normally 5V.
const int model = 2; // enter the model number (see below)

float cutOffLimit =0.001; // set the current which below that value, doesn't matter. Or set 0.5

/*
"ACS712ELCTR-05B-T",// for model use 0
"ACS712ELCTR-20A-T",// for model use 1
"ACS712ELCTR-30A-T"// for model use 2
sensitivity array is holding the sensitivy of the ACS712
current sensors. Do not change. All values are from page 5 of data sheet
*/
float sensitivity[] ={
0.185,// for ACS712ELCTR-05B-T
0.100,// for ACS712ELCTR-20A-T
0.066// for ACS712ELCTR-30A-T

};

const float QOV = 0.5 * VCC; // set quiescent Output voltage of 0.5V
float voltage; // internal variable for voltage

void setup()
{

Serial.begin(9600); // initialize serial monitor

Serial.println("ACS712 Current Sensor");
}

void loop()
{

float voltage_raw = (5.0 / 1023.0)* analogRead(VIN); // Read the voltage from sensor
voltage = voltage_raw - QOV + 0.012 ; // 0.000 is a value to make voltage zero when there is no current
float current = voltage / sensitivity[model];

if(abs(current) > cutOffLimit )
{
//Serial.print("V: ");
// Serial.println(voltage,3); // print voltage with 3 decimal places
// Serial.print("V, I: ");
Serial.println(current,3); // print the current with 2 decimal places
// Serial.println("A");
}else
{
Serial.println("No Current");
}
delayMicroseconds(1);
}

I am using this code, in the serial monitor all abrupt results are coming.

12

wouldn't you handle this by using the sensor as one arm of a voltage divider?