[Arduino IDE demo source code for KC868-A16]--#04-ADC INPUT

[admin]

now the default 4 CH all are 0-5v.  but you can replace two resistance switch to 4-20mA signal.
   
here are two diagram, left is KC868-A16, right is KC868-A4, you can replace 510R with 0R, 1002 with 150R, so that can use 4-20mA sensor.