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RJORG.1
Associate
Nov 15, 2020 8:24 PM UTC
Solved

What is the best way to read sensors to sample 4-20mA sensor with STM32L476RGT6

Hello STM Community!

First of all, I would like to thank you to read my topic and enter in this discussion.

I'm new with STM32, and it's the first project of mine that I really need to worry about energy comsuption.

In my project I have sensor that Input =12V and output 4~20mA.

I waas think to use something like figure below.

However, I don't think is the best way to do when power consumption it's something relevant.

So, with you guys have better suggestion I would aprreciate!

0693W000005BQjdQAG.bmp 

This topic has been closed for replies.
AlexKeisy
AlexKeisyBest answer
Associate II
Nov 16, 2020 12:23 AM UTC

0693W000005BQxzQAG.jpgNeed to correct schematic.

You will have voltage in range from 150Om* 4mA = 0.6V to 150 Om* 20mA =3V.

Also need for fet`s driver.

3 replies

AlexKeisy
AlexKeisyBest answer
Associate II
Nov 16, 2020 12:23 AM UTC

0693W000005BQxzQAG.jpgNeed to correct schematic.

You will have voltage in range from 150Om* 4mA = 0.6V to 150 Om* 20mA =3V.

Also need for fet`s driver.

RJORG.1
RJORG.1Author
Associate
Nov 17, 2020 12:07 AM UTC

Thank you alexKeisy.

I didn't notice that mistake.

However, coul you tell me if this kind approach it's the best one?

(Obs: thank you for the fet's tip ).

AlexKeisy
Associate II
Nov 17, 2020 3:32 PM UTC

This schematic is usable for short distance`s tens of meters, maybe hunderd`s and low electromagnetic noise. I don`t know best way or not :) thats correspond for usage. Maybe it`s need for higer voltage power source, because some value (0.6-3V) drop on the resistor-refer to the sensor documentation. Also ESD protection is very important.