# Problem reading 4-20ma sensors **URL:** \ **Category:** XBee & XBee Gateway\ **Tags:** 4-20ma\ **Created:** [April 25, 2014, 3:42am UTC](https://forums.digi.com/t/problem-reading-4-20ma-sensors/12865 "2014-04-25T03:42:12Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![sherkhan](https://avatars.discourse-cdn.com/v4/letter/s/c6cbf5/32.png) [@sherkhan](https://forums.digi.com/u/sherkhan)\ **Post date:** [April 25, 2014, 3:42am UTC](https://forums.digi.com/t/problem-reading-4-20ma-sensors/12865/1 "2014-04-25T03:42:12Z")
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 [https://www.digi.com/wiki/developer/index.php/XBee\_Analog\_I/O\_Adapter](https://www.digi.com/wiki/developer/index.php/XBee_Analog_I/O_Adapter) 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. ---
**Author:** ![sherkhan](https://avatars.discourse-cdn.com/v4/letter/s/c6cbf5/32.png) [@sherkhan](https://forums.digi.com/u/sherkhan)\ **Post date:** [April 28, 2014, 4:03am UTC](https://forums.digi.com/t/problem-reading-4-20ma-sensors/12865/2 "2014-04-28T04:03:42Z")
This is the diagram. [Your text to link here…](http://s12.postimg.org/v6iftcvml/imagen001.png) 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…](http://s30.postimg.org/mdoxo26zl/imagen002.png) ---
**Author:** ![sherkhan](https://avatars.discourse-cdn.com/v4/letter/s/c6cbf5/32.png) [@sherkhan](https://forums.digi.com/u/sherkhan)\ **Post date:** [April 30, 2014, 10:26am UTC](https://forums.digi.com/t/problem-reading-4-20ma-sensors/12865/3 "2014-04-30T10:26:06Z")
More Info. The AIO Adapter config is XBP24-ZB\_26A7.mxi 0 0 0 26A7 0 [A]AR=FF [A]LT=0 [A]BH=0 [A]CI=11 [A]CR=3 [A]DH=0 [A]DL=0 [A]DE=E8 [A]D0=2 [A]D1=2 [A]D2=2 [A]D3=2 [A]D4=4 [A]D5=1 [A]D6=4 [A]D7=4 [A]D8=4 [A]P0=4 [A]P1=3 [A]P2=4 [A]P3=5 [A]IC=0 [A]NT=3C [A]EE=0 [A]EO=0 [A]ID=0000000000000000 [A]NJ=FF [A]JN=0 [A]JV=0 [A]NH=1E [A]NW=0 [A]NI=AIO\_TEST1 [A]PO=0 [A]PL=4 [A]PM=1 [A]PR=FE1 [A]RP=28 [A]IR=0 [A]SC=204 [A]SD=3 [A]SN=1 [A]SM=0 [A]SO=0 [A]SP=20 [A]ST=1388 [A]SE=E8 [A]ZS=0 [A]V+=953 [A]WH=0 I can read the sensor value througth AI pin1 when connect a 250ohm resistor to ground as shows in picture3. [Picture3](http://s22.postimg.org/hnlzxzam9/imagen003.png) ---
**Author:** ![srlager](https://avatars.discourse-cdn.com/v4/letter/s/f6c823/32.png) [@srlager](https://forums.digi.com/u/srlager)\ **Post date:** [October 7, 2014, 10:31am UTC](https://forums.digi.com/t/problem-reading-4-20ma-sensors/12865/4 "2014-10-07T10:31:46Z")
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. ---
**Author:** ![snacleb23](https://avatars.discourse-cdn.com/v4/letter/s/ee59a6/32.png) [@snacleb23](https://forums.digi.com/u/snacleb23)\ **Post date:** [April 10, 2018, 9:23am UTC](https://forums.digi.com/t/problem-reading-4-20ma-sensors/12865/5 "2018-04-10T09:23:42Z")
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: [https://store.ncd.io/product/2-channel-4-20-ma-current-loop-receiver-16-bit-ads1115-i2c-mini-module](https://store.ncd.io/product/2-channel-4-20-ma-current-loop-receiver-16-bit-ads1115-i2c-mini-module)