Re: [CAD_CAM_EDM_DRO] EMC: why do I have so many problems?

Hi Doc

I'll try to answer some of the questions as best I can....

On Friday 12 October 2001 11:58 pm, whollid1@... wrote:
> Okay, For starters I am not very linux savy at all. and I had to get
> the bdi disk,and ask for help even then to get it up and running. I
> do understand windows,and even dos based stuff pretty well. I am
> going to list my basic machine parameters and then list the questions
> one by one

> the computer is a 200 pentium with a matrox video card. the only
> other card is a pci nic for the home lan if i can get it setup. the
> machine was setup for the bdi install and was somewhat working, and
> therin begins the questions.

Sounds like a reasonable starter for running a basic steppermod based EMC
install on.


> 1: on EMC startup I have about a 50% lockup rate, with either a
> forced power down, or the machine reboots as though i had hit the hot
> reboot button. what is causing this and how do I stop it. When EMC
> does start it never fails in mid stream.

If you are running steppermod, check the ini file and make sure PERIOD is
commented out (or deleted).
There is an issue with stack sizes in Ver 2.04 that will cause an occasional
lock up, but certainly not this regular.


> 2: when I set up the steppers in the ini file and I had to change the
> values going from the old 1 turn/mm to the new 16 turns/inch ( after
> doing the math ) as I was doing the test runs to get the maximal
> speed before it would stall, I would get a " follower error " what is
> this and what do I do to stop it

The PID gains need to be adjusted - I'll leave this one for someone with more
experience in stepper systems to answer.

> 3: EMC has the nasty habit of taking a program and running it but if
> there is a glitch in the g-code ( say a restated g42 prior to an
> intervening g-40 )then it will freeze up and I need to abort and
> start from scratch after editing the code. does backplot have the
> ability to verify the code or is ther a way to make EMC itself check
> the code first for "unrunables", and how do you setup backplot?

Backplot will still suffer from the same 'freezes' - Use the one under the
View menu.

> 4: Is ther a quick and easy way to make this machine home lan
> capable? is the samba stuff on the bdi disk? the other 3 machines are
> all win98

Samba is included on the BDI disk, and the basic network configuration should
have been done during the install. I'm assuming you had to answer some
questions about IP address and host names. If not, switch to a text console
and run linuxconf.

> 7: are there newer versions of realtime patch or of emc that I should
> download and how hard are we talking about to install.

The most up to date rtlinux from FSMLabs is Ver 3.1, but you will loose the
automount support that just allows you to bung in floppies and CDs ala DOS.
If you want to live life on the edge, the realtime patches known as rtai will
also work with the latest CVS EMC sources.
The rtai option does require a fair degree of determination and debugging
skills.

> 8: if I get a servo system off ebay with a isa card is emc so
> customizable that i can point it to the specific adresses or does emc
> only work with some proprietary cards/systems ( this question is
> mainly for future full sized macine work )

Errr, yes, BUT....
At present, EMC will support the Servo to Go cards. If you want to use a
different card, some knowledge of C and C++ will be required so that you can
adapt the source code. Fortunately, EMC is written in a modular fashion, so
just a couple of files would need to be edited. Assuming a simple IO card
with on board DACs and encoder counters, this would probably amount to no
more than changing a few register addresses and read/write sequences.

> 9: is emc finicky about monitor resolution, because when I changed to
> a lower resolution setting it went to a 100% lockup rate, that was
> right before I Fragged the system running xconfigurator

EMC does not care if a monitor is even attached - You can run the whole thing
through a remote terminal if you want. What is more likely, is the video
driver and Xwindows conflicting with some of the realtime linux functions.
I had a load of crashes and lockups running XFree86-4.1 until all the APM
options were disabled in XFree86Config. Even now, if I have any realtime
tasks running, e.g. EMC, and the screensaver kicks in, I can guarantee an
instant and automatic reboot.
Some S3 cards were known to cause trouble with earlier versions of rtlinux,
so it might be an idea to try another graphics card and see if that
eliminates your problem.

Regards, Paul.