If you look for a simple soft PLC to start with PLC programming with FACTORY I/O, SoMachine Basic from Schneider Electric could be an interesting possibility. SoMachine Basic is free, easy to use and it enables to program M221 PLC in SFC and LD. It integrates a free soft PLC which is Modbus TCP server. So, it can easily be connected with FACTORY I/O by using the driver Modbus TCP client.
You have almost nothing to do. The soft PLC includes with So Machine is modbus TCP server and it uses internal boolean variable %Mi. If in your FIO scene with the driver modbus TCP client, you use for instance “coil 3” for one sensor (input), it is going to be %M3 for So machine. In addition, if you use “input 17” for one actuator (outputs), it corresponds to %M17 in So Machine. The one and only thing to do is to take different adresses for FIO inputs and outputs in the configuration of the driver modbus TCP client.