https://control.com/technical-articles/plc-ladder-logic-on-an-arduino-building-a-start-stop-circuit/
IMO, There is one major fault in this attempt to simulate a typical PLC.
The original PLC concept and premise was intended, not only to carry out Boolean logic control of industrial circuitry, but also to display the current status of the Boolean functions in the form of a visual representation.
This in order to rapidly trouble shoot any and all issues with the controlled industrial equipment.
IMO, There is one major fault in this attempt to simulate a typical PLC.
The original PLC concept and premise was intended, not only to carry out Boolean logic control of industrial circuitry, but also to display the current status of the Boolean functions in the form of a visual representation.
This in order to rapidly trouble shoot any and all issues with the controlled industrial equipment.