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Month: September 2015

Re: [trinity-users] Odd ssh -Y problem. A TDEism?

From: Gene Heskett <gheskett@...>
Date: Sat, 12 Sep 2015 05:40:47 -0400
On Saturday 12 September 2015 03:01:20 Dr. Nikolaus Klepp wrote:

> Am Samstag, 12. September 2015 schrieb Gene Heskett:
> > Thanks Nik, the whole alias has been added, after any previous ones
> > it may have found.
> >
> > But I won't test it instantly as I left it sitting there running
> > with all machine power turned off so it remembers where it is in the
> > middle of a job, when my diabetic feet said it was quitting time.
> >
> > Cheers, Gene Heskett
> Hi Gene!
> Just a question: You run XFCE ot TDE on LinuxCNC?
> Nik

XFCE I believe as I am looking at the mouse while its initializing after 
my login on a reboot.

None of those machines have more than 2Gb of ram in them, so the X used 
is usually "lightweight".  2 of them are D-525MW Atom powered intel 
boards, which we found to have the lowest IRQ latency of the lot.  
Unfortunately its discontinued but if you can find one on ebay, the 
asking is about 4x what Intel sold it for 4 years back.  The "bell" 
curve on that board peaks at around 3 microseconds.  Some highly rated, 
and high priced boards are so poor in that regard that extra hardware 
help has to be installed.  The problem when running stepper motors via 
cpu, aka with software stepping is that at say a 10 kilohertz step rate, 
a 10% variation in the timing of the next pulse issued costs you 50% of 
the motors power as it will fall behind, then be incapable of catching 
up so it stalls.  That usually equals a wrecked part, and/or broken 

So for the bigger, faster stuff, that usually is offloaded to a 
programmable FPGA card which does the high speed stuff, leaving the main  
thread to run at 1000 times a second, doing all the floating point 
stuff.  Those accessory cards can usually move the machine 3 to 5x 
faster than the cpu itself can, depending on the available voltage for 
the motor power.  At the higher speeds, motor winding inductance limits 
the current, and available torque.  Below those speeds, the driver 
regulates the current so you get full torque. So voltages north of 24, 
on up to the 160 volt range in the bring money in little red wagons 
category.  Those are fast, meters a minute motions, accurate to .005mm 
in the line they traverse while moving half a ton of machinery that 
fast.  If cutting metal at those speeds is wanted, 25 hp water cooled 
30K rpm spindles are needed.

Thanks Nik.

Cheers, Gene Heskett
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <>