You can use a load resistor to read a 4-20mA input using a 0-10VDC PLC input.

You only need this lesson if you are using a 0-10VDC input and want to do the 4-20mA lessons.

Using Ohms Law, Amps X Ohms = Volts so we can calculate the milliamp value for a given voltage. If you use a 125 ohm resistor then 4mA will be 0.5VDC and 20mA will be 2.5VDC. If you use a 250 ohm resistor then 4mA will be 1VDC and 20ma will be 5VDC. If you use a 500 ohm resistor then 4mA will be 2VDC and 20 mA will be 10VDC.