I can now run EMC2 and it kind of "works"

PCs are cheaper than dirt, and Linux and EMC2 are free. There is no point in trying to have one PC control multiple machines *unless* you are also multitasking the drives and I/O boards between the machines. I do this with one PC and set of drives controlling either CNC plasma or CNC mini mill. If you aren't sharing the drives and I/O boards, it makes little sense to try to share a lousy $99 PC.

>

Maybe, but doing things in a configurable way like this, makes for clean, understandable computer settings. I could run two devices off of one PC if I wanted to. I am not saying I should. What I did is I avoided hard coding anything.

i

?FixingSMIIssues You can improve reliability and response on your EMC2 system by decreasing hardware latency caused by the System Management Interrupt.

I ran Neils Jalling's hack on my EMC2 system and it decreased jitter by ~ 5% and caused the dreaded "following error" to disappear.

The thermal control hardware continued to work properly on my system after the hack but there are rumored to be systems that will overheat because of thermal routines handled by the SMI.

--Winston

Thanks. I did not think about it. This is an older PC "designed for Windows 2000" and thus is unlikely to be exposed.

In addition, I close the velocity loop with tachometers (changed my mind again and I am using tachs as of now), so that alone could help with jitter. Even if the CPU is taking a millisecond nap, the servo drives maintain velocity.

If/when I get my mill to work, I want to buy a mini-ITX case with a new mobo, SSD etc and will put it inside the control cabinet. When I look for hardware, I will double check the SMI issue. Maybe I will get AMD hardware.

i

If you want to go compact and in the control cab, look at PC104 form factor systems and some of the other industrial PC variants many of which are not expensive and are specifically designed to run Linux. Try the advertiser index on circuitcellar.com if you need a starting point.

Well, I picked a few newegg items, if all goes well, I will buy them:

?Item=N82E16813121381?Item=N82E16820145184?Item=N82E16820167025 I asked my friend, who is a computer build expert, if they will fit together, but I think that they will.

i

SMI has been on Intel processors since < Feb. of 1992.

It couldn't hurt to check. See Message 3 under:

--Winston

(...)

AMD began supporting SMI before Intel.

__________________________________________________________

Beware! I have not been able to get Linux or EMC2 to run on SATA drives, just PATA. I understand that some folks *have* been able to do this by patching the OS, however.

--Winston

That is the weirdest thing I heard this week. I do not know what to make of this.

i

Another minor bit of progress: I was able to set up the Y axis parameters enough, so that when I turn "machine on", it holds position and when I press up and down arrows (which control Y axis in EMC), the position changes and is then held.

I was doing this from away from home, so I am not totally sure that it worked right, but it looks to me like it did.

The only problem is that the position that is held, is not very stable, and changes from, say, 0.2345 to 0.2344 to 0.2346 and so on. I think that it is because I have not yet done PID tuning, have not adjusted gains and Test/Offset on the drives etc. I am not losing sleep over it, because I am supposed to fix it once I hook up the servos to ballscrews.

I think that the next thing I should do is wire limit switches and estops and test all that with the servo motor disconnected from the leadscrew.

Things are progressing much faster right now than I expected 2 days ago.

i

Try entering some G code commands in MDI mode, something like G01 Y10 F25 or G01 Y0 F10. It's more fun to watch it do a move on it's own than to just jog it with the keyboard.

My takeaway: Run the latency test before buying your mobo, if possible. Some configurations just aren't compatible without significant blood sweat and tears.

--Winston

I think that it cannot do it until I home it. It says "Cannot issue MDI commands until homed". And I cannot yet home this mill.

i

You should be able to manually home it, i.e. tell it "this is home".

I do not know how to do that -- no one I know has a Mini-ITX motherboard.

I will ask on the EMC2 forum.

i

Which one do you have? I have several different Mini-ITX boards at work.

Ubuntu runs just fine on a Mini-ITX EPIA-CN with SATA drives.

With EMC2 running properly? I think the issue here is not Linux running on it, it is EMC2 running under Linux on it without timing issues that screw up the servo loop.

(...)

From a booted, idle screen,

Press F1 (Which turns off eStop) then, F2 ("Toggle Machine Power") then F3 (Manual Control).

Locate the Home key on your keyboard and press it once. Select the next axis (Y) and press the Home key once more. Select the final axis (Z) and press the home key again.

Continue selecting and Homing until you run out of axis'.

Welcome Home.

:)

--Winston