well, succeed in making a mirror with the help of the LM358.
Basically, what I do is with the first Ampop (12v source) is to convert the 4-20mA 0-5V input voltage ... that, I do mirror the output of a PWM pic and put it in a second Ampop (24v source) which transforms 0-5 in 4-20mA.
While this project could be implemented to build a current source 4-20mA, the initial idea is to add it to a tank level sensor home made. ( The sensor consists of several magnetic sensors with 0 ohm resistors ... with a floating magnet, according to the water level switches enable me )

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I think in the future, I will make the display and will try to take a pic 8 pins (just need an analog port and another port for pwm)


sorry for my spanglish!!!!