Hi Jeffserv,
There are a number of options to write code on the PC. Users like to use many different languages. Our underlying PC Libraries to perform Coordinated Motion, Trajectory Planning, GCode, etc... are written in MFC C++. But if you wish to write C# .NET code then the .NET interface makes that possible without caring or knowing what language the libraries are in.
Besides the built in functionality KFLOP only supports adding User C programs. Programs written to run in KFLOP (not the PC) must be written in C. C works well for small, simple, low-level, real-time control tasks. You usually must make use of some C programs. But usually these can be minor changes to existing examples.
It is usually easier to write and debug code for the PC. So it is usually preferable to write code that runs on the PC. But the PC is not real-time (it may sometimes freeze for a second or more). In some applications it may be ok to occasionally have a delay, but in other applications missing a deadline would be disastrous.
HTH
Regards