It has become popular to use Arduino or Raspberry Pi together with a Shield card to connect and experiment with PLC control and programming. But if I was interested in doing a similar thing directly ...
The MAXREFDES64# reference design features 8-channel digital inputs with isolated power and data. The design integrates a 600VRMS data isolator (MAX14850); a STM32F1 microcontroller; a FTDI USB-UART ...