the sensors need 10-30 vdc to work with 4-20 amp outputs
If you mean 4-20 mA outputs, just use a 250 Ohm resistor in the ground lead, and read the voltage using analogRead().
See below.
To protect the analog input from overvoltage, add a 10K resistor in series with the sensor output. To optionally reduce noise, add the 100 nF capacitor, C1. Don't forget to connect all the grounds.
