Controlling 4-20mA Sensors Accuracy

finally i am able to read the data from the Temperature sensor using this current loop receiver but i am not able to convert this data into temp value… any help in explaning how this conversion works will be grreat…

Thank you

1 Like

Hi @Derbo43

There is a table in the datasheet you linked to for you sensor that shows the current values for 4mA, 12mA, and 20mA and the associated temperatures. The table depends on which exact sensor you have since there different ranges (0 to 50C, 0 to 100C, etc.)

Without knowing more about the board than they publish I can see that it is hard to map the 16-bit ADC readings to the 4-20mA currents. I am sure there is a simple mapping but the easiest thing is to just calibrate it.

Assuming your sensor goes to 0C, but it in an ice-water bath and let it stabilize for a few minutes. Check the 16-bit readings (somewhere near 0) and call that 0C. The repeat with any other known temperature (room temp, boiling water, etc.) and you will have the scale.

You could also calibrate the range with a battery, variable resistor and a milliammeter. Use the battery and variable resistor to set up a voltage divider and with the milliammeter in series set it to 4mA and check the ADC reading.