Power arduino from 4-20mA sensor measurement line?

Question

Arduino

the question is how to connect the arduino to the break in the sensor power circuit and at the same time take readings, leaving the original working circuit?
schema example : https://goo.gl/e5XmZB

Answer 1

www.arduino.md/arduino_power_consumption
Judging by its gluttony, it's not a very good idea.
In general, there are MKs that can theoretically be screwed up, with low power consumption ( for example ). You just need to think about the wiring diagram.
It should not particularly distort the readings, since the circuit will maintain the current depending on the signal level from the sensor (up to a certain voltage level, however).

Answer 2

The value of the signal on line 4-20 is carried by the current, any attempt to add consumption will distort the signal. What a strange desire to stick a controller in series in the line.

Answer 3

The sensor will maintain the desired current in the circuit itself. Include a 150 Ohm 0.1% resistor in the open circuit and measure a voltage of 0.6..3V from it