Need help with arduino portenta device

Im trying to design a handheld device that would help me diagnose failed components. A quadrature encoder and a SSI linear positioning transducer. I have most of the electrical design done. I would need help with the firmware. Basically. I would like to read the signal from the encoder and The transducer and display it on a screen (preferably an oled screen). And also replicate those signals. The idea behind the device is I want to hook up on the ( encoder let’s say) spin it by hand and see if it still works ( see if all channels are working ) then if it’s working, unhook the encoder and hook on the cable and create an encoder signal to send to the PLC, to see if the wiring is good