I am not sure what you are getting at or why this is automotive?
You apparently have two sensors that are powered by 24 VDC, would that be correct? Each sensor has an output of 4 to 20 mA which is very common. You do not mention what the sensors are measuring? You don't mention what the PLC input is supposed to be? If the PLC input is voltage you would run each current output through a precision resistor, for example 4 to 20 mA through 500 ohms gives you a 2 to 10 volt input, 4 to 20 mA through 250 ohms gives you 1 to 5 volts. That said if you have a single input you would MUX (Multiplex) the inputs. You can't simply parallel sensor outputs. What exactly are you trying to do?
Ron