Am I thinking about this correctly?

[Firebrick43]

I would disagree with that. I have successfully done it, over Ethernet, and it does not require much of a PC to pull it off. But it does require pre-compiling the controller code and making sure you keep the command buffer full. The command buffer in my case is 512x80, so lots of room. In most cases it takes several seconds to even several minutes to run the buffered commands, so any minor pauses in data transfer are not even noticed. It normally takes about 100ms to transfer 400 lines of commands to the onboard buffer.

That is why I include the word "typically"

And I would agree with you that older computers do better, more the software and way it processes it. But those days have sailed and 386/486 boards are actually prohibitively expensive now as there is such a market for them for old industrial controllers.

Windows 10/64 bit controllers don't work as well, in this regard. There is a reason every large manufacture has a discrete motion control processor and a separate HMI computer.

As to the buffer size, depends on machine and what its doing. Some 3d profiling programs, peck turning, or trochordial milling and your buffer is really small.

 

[JimDawson]

Windows 10/64 bit controllers don't work as well, in this regard. There is a reason every large manufacture has a discrete motion control processor and a separate HMI computer.

My software runs fine on a Win7/10 64 bit computer. My system does use a high end dedicated motion controller that does all the heavy lifting. The PC only really does HMI, file management, and G-code translation functions. I have not noted any system lag when running complex 3D profile or trochoidal tool paths, nor have I noted any issues when peck turning on the lathe.