I have a pressure transmitter.The address below has the datasheet.
I added below in the circuit diagram and code that I made.

#define potpin A0
int deger=0;
void setup()
{
Serial.begin(9600);
Serial.println(“Pressure Transmitter”);
}
void loop()
{
Serial.println(deger);
delay(1000);
}

https://www.pakkens.com/media/products/mps-10-128/pdf/tr_TR.pdf

Post a link to an English documentation!

Appears you have a 4 - 20mA sensor, but what is the pressure range (0 - ? Bar)? What is your power supply voltage (9 - 35V)?

I am using a 12v power supply, Pressure transmiiter is 0-50bar ,4-24ma, 9-35VDC

https://www.pakkens.com/media/products/mps-10-128/pdf/en_US.pdf

What output do you get?

With a 4-20 mA sensor like yours, most people use a 250 Ohm resistor as the sensor load, and simply use the ADC to measure the voltage across it, as you seem to be doing.

To calibrate the setup, record the ADC value for a few known pressures, and fit a straight line to the data points.

To obtain higher precision, use oversampling and averaging. For example, if you add up 64 ADC measurements (use an unsigned integer for the sum) and divide the sum by 16, the result has 12 bits of precision rather than 10.