Re: [CAD_CAM_EDM_DRO] EMC and freqmod

Terry Toddy wrote:

> Is the EMC freqmod used only for closed loop stepper control or will it
> work on a simple open loop system? I was successful running steppermod
> but always get following errors when I try the freqmod.

It can be used either way. You need to tweak the P term, and maybe a few
others, such as max_accel, to get the best operation with your own
stepper system.

> Also, I am having a problem with my RTLinux. After booting my system I
> can run EMC fine for about an hour then system response starts to slow
> down eventually coming to a complete stop. I have to do a hard reset of
> the system and can run for another hour or so. Memory leak in the RT
> system?

Very interesting. Which GUI are you using? If you are using Tk/EMC, try
xemc and see if the same problems show up.

> I am using RedHat 5.2, with upgraded kernel headers and source from the
> RedHat site.
> kernel-headers-2_0_36-3_i386.rpm
> kerner-source-2_0_36-3_i386.rpm
> Real Time patch release 9.
> EMC 07-June-2000

I am using RedHat 5.2 (2.0.36-0.7 kernel) with the 0.9J RT patch.
But, I am using the 20-Dec-1999 version of EMC, the last one where
the Tk/EMC gui worked with total reliability. This is on my CNC machine,
and has run for entire days without trouble, for about 2 years of experience.
This is using the Tk/EMC gui. This is an Intel Pentium ATX motherboard
with a 100 MHz Pentium Classic CPU.

I also have the same version of the kernel on another machine, with a 333
MHz Pentium II CPU. I am running a 15-MAR-2000 (I think) EMC on this
one, and Tk/EMC will lock up the keyboard, mouse or both after a while.
I haven't noticed a slowing down of response before it croaks, it is sudden.
If I use the xemc gui, it is reliable, too. I had this up a the NAMES show
and it ran flawlessly for 2 days without reboot, cutting air almost constantly.

I would also like to see this problem cleaned up. Apparently, if you use the
latest kernels with the later EMC versions, it works pretty well, but still will
hang up once in a while. I'm staying with the old stuff until this problem
is fixed.

Jon