In the PLC, CPU module, I / O modules, namely what role

CPU module is the control center of the PLC. It functions in accordance with the procedures given PLC system receives and stores from the programmer type of user programs and data; check the power supply, memory, I / O and watchdog timer status, and diagnose user program syntax error. plc IO module is the interface between PLC and site control interface input channels. Therefore, the manufacturer of the PLC power supply design and manufacturing very seriously. Programming plays a role in the design and commissioning of the plc.