Best Computer for LinuxCNC and Connecting to Stepper Drivers

Discussion of linuxCNC (formerly knows as EMC2)
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Joined: Fri Jun 15, 2012 1:05 am

Re: Best Computer for LinuxCNC and Connecting to Stepper Dri

Post by unterhausen » Wed Jan 01, 2014 5:03 pm

edwardrford wrote:In my (not limited but not extensive) experience with EMC2/linuxCNC : If you can successfully install it on the machine, it will be sufficient. I sometimes get RTK errors when I startup linuxCNC, but have never seen any side effects from them. I just dismiss and carry on with what I was doing. They've never happened during a job...
I can't dispute the side effects statement, but there is only one error reported, after that it doesn't report the errors any more. The way to test a computer is to boot from the livecd image and run the latency test from the menu. Run glxgears and do some surfing on the web and if there is going to be a problem, it will show up on the latency test window. There are a series of changes suggested on the linuxcnc wiki if there are latency spikes. On my desktop, I had to go to a different video driver. Step and direction on a machine like the shapeoko may not show a latency spike because steppers are pretty robust to that. On a big machine with rigid mechanicals it will show up as surface defects and possibly other problems

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Joined: Mon Nov 11, 2013 5:20 pm

Re: Best Computer for LinuxCNC and Connecting to Stepper Dri

Post by samc99us » Wed Feb 12, 2014 6:06 pm

Step and direction spikes will show up in the SO2!! They sure as heck showed up in my CNC foam cutter running an offboard 25 KHz oscillator for reference time!

Fortunately, so far my setup has been very solid. I'm running LinuxCNC on a stock SO2 using a HobbyCNC Pro driver board, coupled to a 1.2Ghz AMD Duron board w/ onboard graphics, a rosewell PCI parallel port ( ... allel+Port) and 1Gb of memory. This PC isn't connected to the internet, my jitter test says 21,800 when moving files around. I may do some more testing today, as I feel it probably has higher jitter than that when copying from the memory stick.

All in all a solid setup, don't regret it at all!
Modified Shapeoko 2: 1500mm fully supported y-axis, 1000 mm 4060 x-axis, ACME Belt Drive Z-axis, Dewalt DNP611, full aluminum t-slot table, 4x NEMA23 180 oz/in stepper motors driven by a G540

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