That is no CPU. That is a PLC.
I presume it has serial/ethernet/whatever interfaces. And that there is some data protocol going on over those interfaces you want to work with. As such it could as well be any other computer you want to communicate with.
Your question is too vague.
Do you know how to program? In C/C++, Java, Python, whatever? Do you know Linux? Do you know those protocols you want to deal with?
In short, I'm sure it's possible but we need more information on what it is you actually want to do.
Memory in C++ is a leaky abstraction .