Does anyone can give me a tip how can I read a current from a sensor that outputs values between 4-20mA.I know this evolves a electronic circuit to convert the current to a voltage to apply on the analog input of arduino, but I cant find info about that
Looks like putting the signal across a 250 ohm resistor will give you a signal from 1 to 5 volts (4 to 20 mA)
As stated a ground based 250 ohm resistor will drop 1-5vdc for direct measurement to a arduino analog input pin. However the "2-wire loop" must be powered by an external DC power source. The typical loop supply voltage is +24vdc but many will work with a 12vdc power source, depending on the 'compliance voltage' rating of the 4-20ma sensor. Be sure you also run a wire from the external dc negative terminal to a arduino ground pin.
hoow how can't I think that before!
Very easy way to get the measure.
Sometimes the solution is just above and we can't see it
Many thanks to all of you for the great help