PI3 has a good support for the UART serial connection. If I am not wrong the difference between the RS232 and RS485 is that the second is based on differential currents on the signals to compensate / avoid some kind of external interferences and work with higher currents than the 5V of the 232. What you need I think it is a small circuit to convert the 485 industrial serial connection to the TTL level of the UART in the PI, as well as you should do if you will use a 232, with a Max chip (just for an example).
In my opinion, also to avoid to spend a lot of time to make a conversion circuit by yourself, FTDI already provide USB to 485 adapters together with the USB to 232 based on their FTDI232 and FTDI485 chips. You can get the chip specifications to integrate the conversion circuit in your own project or just buy an adapter (at least to test the prototyping phase and develop proper software on the Raspberry PI).
PI3 has a good support for the UART serial connection. If I am not wrong the difference between the RS232 and RS485 is that the second is based on differential currents on the signals to compensate / avoid some kind of external interferences and work with higher currents than the 5V of the 232. What you need I think it is a small circuit to convert the 485 industrial serial connection to the TTL level of the UART in the PI, as well as you should do if you will use a 232, with a Max chip (just for an example).
In my opinion, also to avoid to spend a lot of time to make a conversion circuit by yourself, FTDI already provide USB to 485 adapters together with the USB to 232 based on their FTDI232 and FTDI485 chips. You can get the chip specifications to integrate the conversion circuit in your own project or just buy an adapter (at least to test the prototyping phase and develop proper software on the Raspberry PI).
