Looking for cheap linuxcnc-2.8.2 capable PC with parport - recommendations

Hi all,
I am running my home-made parallelport-controlled CNC since 2010 with an very old 32-Bit PC and very old 32-bit linuxcnc versions (Ubuntu 10.04). Its for hobby purposes only.

Now it is time to get a new cheap/small/compatible PC to control my parpport-CNC machine since the old OS versions are no more compatible to internet websites and latest tool version. I would like to do some CAD/CAM on this machine as well.

I would like to get some recommendations, for what I have to look when getting a new PC to drive my CNC.
Her some of my thougths:

1. It shall be a cheap PC, preferrably with BIOS and not UEFI - my experience with UEFI is rather NIL, and I always read about booting issues with UEFI, especially when using USB-bootimages.

2. A parallelport is required - as I have read, there are PCI parallelport cards which are working fine.

3. It could also be a small industrial PC or a RASPI solution - but I also would like to do some CAD/CAM designing on the same PC. Is this efficiently doable on a industrial PC or RASPI ? 

4. What about Parallelport + RASPI - are there any working solutions ?

I just want to avoid to by an cheap 64-bit machine on ebay, and then learning that it will not work with my parport-CNC.

Thanks for any hints.

 

Thanks for the crisp response.
Can you give an example for "enterprise" models from HP, Dell, Fujitsu ?

From Dell can find "Optiplex" or "Precision" models - but I am not sure if this is an enterprise device.
From Lenovo "ThinkCentre" or "Elite" ?

Hmm, a lot of old PCs are out there.

What if I want to use my Lenovo Laptop - is there a device available that translates USB or serial into a parallel interface which can be used with linuxcnc ?

Not sure if it would be interesting to you, but I am sort of in the same boat as you except that I don't have any desire to do CAD/CAM at the machine. I can take my laptop to the shop if I need to do that and access files through the network, or via USB Stick. For that reason I just wanted the most streamlined solution for my paraport machine. Here are my 2 finalists.

1. Raspberry Pi with a Mesa 7i92. They hook together with an ethernet cable and the 7i92 has a DB25 that will plug directly into the paraport. From there it is configuration in LinuxCNC. This is a pretty well proven solution for machine control but would not be suitable for CAD/CAM. RPi is about $100, 7i92 is $89

2. Orange Pi another single board computer like the Raspberry Pi, except this one should be able to provide the step rates I need without needing a separate card. I ordered one of these and it should arrive later this week. Cost was about $50 shipped. I plan to make a cable to connect the input/output pins of the Orange Pi directly to the parallel port breakout board on my machine. Info for this is at these links. forum.linuxcnc.org/18-computer/39037-lin...-orange-pi-allwincnc and allwincnc.github.io/

I'm going to give the Orange Pi a go with the RPi/mesa as fall back plan. I already have a RPi that is my sons that I have been playing with in simulator mode and that works rather well.

Okay, since this Mesa 7i92 is connected via Ethernet, does the PC still need the real-time kernel ? I guess so ....
If not, I could just use the latest 32-Bit Debian OS on my existing PC and connect the Mesa 7i92. But most probably I need the realtime OS kernel, right ?

Edit:
I do have a 2nd Lenovo T530 laptop - I understand that there might be issues with power-saving, but before buying a new (used) desktop PC, I would give it a try T530+Mesa 7i92.

The latency test on the T530 (via Linuxcnc 2.8.2 LiveCD) gave the following numbers after ~5 minutes with glxgears, Youtube and browsing:

Servo(1ms)  Max. Int.(ns) = 1163168  Max. jitter(ns)= 163294
Base(25us)  Max. Int.(ns) =   127393  Max. jitter(ns)= 162393

I read somewhere that any value below 50000 is good, but since my speed performance is not very high, I think it might be good enough.



 

A question to tommylight - in another forum-discussion, you mentioned you are also running a laptop with high latency, and thus you had to "bump up" the CNC setting to make it work properly - what exactly did you mean with "bump up" and what ?