Seeking some troubleshooting advice

[jim_stoll]

I've got emc up and running under the 10.04 distribution. It is running well enough (I use the mill several hours most days), but I'm occasionally getting an rtapi error, and if I don't have emc running, the machine will invariably crash within a few minutes. If I have emc up, it will run pretty much indefinitely (I've left it on for days at a time), though I do occasionally see the rtapi warning. (Not often - maybe once every 10 sessions or so.)

Another thing of note, and this maybe normal, but once I start up emc (I use Axis, so whatever bits and pieces of emc are running when Axis is going), the machine becomes largely unusable for anything else - even alt-tabbing to the calculator is slow, scrolling in gedit is painfully slow, trying to fire up Firefox or Chrome to look something up online is just about un-doable. Once emc is shut down, these apps become very reasonably responsive.

While an older machine, my setup is nothing terribly decrepit (I'm at work, and the machine is at home, so I don't have any specs in front of me.) I ran the latency test and used the numbers generated there (again, machine at home, I'm at work), so I can report those numbers back, if it helps. They weren't too far off of what my old setup on my old machine was, so I didn't consider them worrisome. (Old setup was still running the Ubuntu 6 version, and wouldn't run the 10.04 version.)

I'm not looking for major hand-holding (yet :-), but am seeking some directions in which to look that are most likely to yield results or usable information. If there are specifics that I can provide to help, please let me know.

Thanks!

[CaptainVee]

I think that it is probably the realtime kernel working that slows the rest down. The real time kernel gives priority to emc over anything else. So if your machine has some trouble it is not strange that other software slows down.

What kind of latency figures are we talking about here, with what kind of hardware?

What I do not understand is what you mean with the first part of your post. Have the machine running without emc "up"

[jim_stoll]

Oops, sorry, didn't get this until now (back at work, of course :-) I'll reply with latency numbers this evening.

On the 'up and running' comment - I mean just the PC itself, without the emc/axis program started - just boot up, log in and either let it sit there, or startup other apps, but not emc/axis. When I do this (ie, PC/Ubuntu running, emc/axis not running), it will crash within a few minutes. Similarly, if I use emc/axis, all is good - no crashes, but if I then shut emc/axis down and let it sit for a little while, it crashes. There's something going on, with emc/axis keeping the machine 'busy' or something, that seems to prevent the crash, but without emc/axis running, its guaranteed that its going to crash. I haven't been able to get any error messages when it happens - the screen is blank, or blank with some large vertical white blocks, but I haven't seen any text. Just curious if others have had similar behavior, or if this is some personal oddity.

Good to know that its not uncommon to have emc hog up the CPU and/or OS - its not a huge deal, I just wanted to be sure it wasn't indicative of some larger problem, especially in the context of the crashes.

Thanks for your assistance!

Jim

[cncbasher]

you dont say which version of EMC you are running 2.4.x or 2.5 etc
or the spec of the machine , so it's difficult to pin down exactly , but could be your missing some update.
you should have a minimum of 1gig of ram also

the crashing you describe , could indicate a possible hd / graphic failure on the horizion
or that the pc is just not up to running emc and is marginal

just so many variables to pin down

[andypugh]

Another thing of note, and this maybe normal, but once I start up emc (I use Axis, so whatever bits and pieces of emc are running when Axis is going), the machine becomes largely unusable for anything else

Try a longer base-period, and see if that costs you any rapid speed. If you are hitting mechanical limits before software limits then there is no point running too short a base period.

What you might have is a slow computer with reasonable latency, so that it can handle the base period timing, but the execution time of the thread doesn't leave much time for anything else.

eg, a latency of 10,000nS but a machine which takes 9,000nS to run the base-period tasks will give fast stepping, but sluggish performance. Increasing the base period to 20,000 would massively increase performance but would have peak step rate. However if the steppers stall out at 1kHz, that's no problem.

[helpmeout]

when i first installed ubuntu/emc2 on mine with xp as the second boot-up. i could not get it to run hardly at all. i found a video-card that was laying around in some of my junk. a decided to see if that was my problem the computer i use has an onboard video that kept emc2 from running give that a whirl and see but just use an older video card, you might have an older one lying around also.that fixed mine.had to go into bios setup and tell it to use the add-on card tho.