Problem reading 4-20ma sensors

Hi all.

Im having problems reading some 4-20 ma sensors with Xbee AIO Adapter.

I can read correct values of sensors with arduino using a 250 ohm resistor to convert 4-20ma to 1-5V and appling +12V to the sensor with and exteral power supply.
I can see how change the value when i apply heat to the sensor.

But when i connect the sensor to de AIO Adapter in 4-20ma mode, its reads always the same value (122). This value readed dont change the value when i apply heat to the sensor.

I follow all the instructions correctly from and i set terminal 1 and 2 for 4-20ma mode, d0 and d1 to 2 for analog input and P3=5 to output the 12V to the sensor. I also put on the dip switch 2 as manual says.

Any suggestions?

Thanks in advance.

This is the diagram.

Your text to link here…

In this first image the multimeter shows me a 10 mA current, so the sensors works fine with the supply voltage of AIO Sensor.

But if i disconnect point A and connect it to pin1 on AIO Sensors as shows in picture 2, the multimeter shows me a 2 mA value.

So the sensors doesnt works when i close the circuit into AIO pin.

Your text to link here…

More Info.

The AIO Adapter config is


I can read the sensor value througth AI pin1 when connect a 250ohm resistor to ground as shows in picture3.


Did you solve your problem? Because I have the same when I use RS-485 Analog I/O Digital I/O works properly coupled to resistors, however when sensors 4-20mA are coupled didn’t work.

Hey I know its oldest question of the forum but is your project is in working fine ? If yes can you help me out with schematic as i am also trying same with the help of 4-20mA current loop receiver as mentioned below: