send serial data through serial port of PM554

Hi

I have data from shaft position and speed of motor , I want to convert these parallel data to serial and send these serial data with serial port of PLC PM 554(port: com2, Physical link: RS-485) instead of using absolute encoder .I want to know how to make synchronous serial fram bit (ssi) , set clock and send it with serial port of PLC .

does any one know how can i do this work and introduce a reference for study in this case?

Thanks for any help