Windows embedded (7) - repurposing a thin client PC

[Doddy]

Aha, didn't notice the "plus" range. Okay, one in the post and I'm going to try a LinuxCNC / parallel-port install.

If you'd like I'd be happy to try installing UCCNC in demo mode prior to the linux install, to understand any installation issues, though with the licensing I don't think I'll be able to drive my mill directly - but I think if the demo works then it should be just about there.

[Kitwn]

m-c,
My understanding is that the best controllers are simply taking their control data and the raw G-code from the PC and generating all the control pulses themselves without having any of the other calls on their processor that go with running an operating system at the same time. This has to be the best way to go in terms of optimum pulse timing but is also the more expensive option. Being able to download a G-code file via ethernet and let it run while the computer is used for other purposes is also an advantage of these more modern designs and is definitely the best way to go both technically and for ease of operation and throughput of work.

My recommendation of LinuxCNC on an old PC is primarily aimed at budget conscious hobbyists like myself. It's cheap, it works, it lets you concentrate the available budget on the mechanical hardware when you first get going. Then you can start making things while you learn just how many worms there are in the CNC can

I use a dedicated PC running only LinuxCNC and did some measurements of step pulse timing a while back. What should have been a continuous stream of pulses at 125uS intervals had most pulses at 125uS but a fairly regular pattern of intervals of 100uS and 150uS as well. There isn't any obvious vibration on the machine, but this is the only CNC machine I have ever used of so haven't any experience of perfectly timed pulses to compare it with.

In the unlikely event of finding myself with nothing else to do I could try building an oscillator to produce a well timed series of pulses and make a comparison but that's not going to happen anytime soon.

Kit

PS Doddy: Saw your reply after finishing the above blather. LinuxCNC is fairly easy to get going if you build a vanilla 4 motor machine and will run perfectly well on an old Windows-XP era motherboard. The LinuxCNC forum is very helpful.

[m_c]

Doddy, personally I wouldn't recommend using a parallel port to anyone now, as even LinucCNC has compatability issues. However, it's always worth a try before buying an external motion controller, especially if you're build is using a parallel port BOB.
A UC100 is only €80, if that fails.
And I very much doubt that if UCCNC ever gets ported to linux, it'll be free.

Kit, only standalone controllers take the raw g-code. Everything else, the PC is taking the G-code, and generating a buffer of small movements, which are then sent to the motion controller. There is a quite a grey area though, as to how much is handled by the PC, how much is handled by the motion controller, and how the two interact. I can explain more, but I've not got time just now.

[Kitwn]

I can explain more, but I've not got time just now.

I'm sure you would have many grateful readers of a detailed write up on that. Me among them.

Kit

[Doddy]

UCCNC on linux was a bit tongue in cheek, I’ve bought it and an UC300ETH for my mills, and would happily slave a couple of I/O for the lathe as well... but it doesn’t do Lathes well. The only reason I have any windows boxAnywhere in the house now is for UCCNC. I do most of the CAD/CAM in the warmth and use the cloud to transfer from Mac to windows in the shed where it gets final fettle before cutting.

Parallel ports?, if they work they can be reliable, they/the signaling doesn’t scare me. If I could find a reliable but cheap Ethernet motion controller for Linux CNCdrive then I will but first stop is trialling Linux CNC in anger before committing to a rabbit hole technology. My plan is to avoid windows where possible.