I am working on a project to collect and change the data into a PLC. I would like to work with any PLC manufacturers so I guess the best way is to create my own modbus communication protocol and not use the OPC protocol (to avoid to be dependant of manufacturers).
What do you think it is the best: OPC protocol or directly in ModBus protocol?
Also, I found modbus libraries libmodbus and nmodbus what do you think about them? Do you think my project is feasible?