On Sunday 28 April 2019 14:03:21 Gene Heskett wrote:

> On Sunday 28 April 2019 10:53:49 Peter C. Wallace wrote:
> > On Sun, 28 Apr 2019, Gene Heskett wrote:
> > > Date: Sun, 28 Apr 2019 10:47:13 -0400
> > > From: Gene Heskett <[email protected]>
> > > Reply-To: "Enhanced Machine Controller (EMC)"
> > >     <[email protected]>
> > > To: [email protected]
> > > Subject: [Emc-users] stretch testing install Q
> > >
> > > Greetings;
> > >
> > > As I wrote yesterday except for two things.
> > >
> > > 1. It won't let me run synaptic from anyplace but its own
> > > keyboard. 2. Very consistent and poor latency in the 53
> > > microsecond range.
> > >
> > > Something in pam is stopping synaptic.
> > >
> > > And is there anything I can put in the kernel command line that
> > > will improve the latency?
> > >
> > > To PCW, is that latency enough to bother a 5i25|7i76 combo where
> > > there is no base thread?
> > >
> > > It seems to be quite consistent, you can clear the stats and its
> > > back above 50 u-s by the time you've unclicked the mouse. And I
> > > just noted that removing the base-thread drops the servo to around
> > > 30 u-secs.
> >
> > 100 usec is usually fine for Mesa PCI hardware and even 500 usec
> > would be OK if the DPLL is used to retime things like encoder count
> > and step count sampling
>
> ISTR seeing that in the 5i25 docs someplace. I think I was using it in
> a previous config. I think I am using that in the pi<spi>7i90 on the
> Sheldon as the pi's latency is known to be over 100 u-secs regularly.
> yes, in the .hal file for a 7i90HD:
>
> setp hm2_[HOSTMOT2](BOARD).0.dpll.01.timer-us -150
>
> is that the right syntax for a 5i25? Must be, it just accepted a -50
> according to the startup log on the G0704. The other 2 machines are
> running on 5i25's and D525MW mainboards with 6 u-secs max latency.
>
> Latency-test measurements on the pi are probably confused. in real
> life as theres a 2nd, very slow thread also running on the pi,
> handling the joggin  and such functions. I have a pair of the MPJA 100
> ppa dials mounted on its apron to replace the old manual cranks, and a
> 100 to 200 millisecond thread handles all that extra stuff nicely with
> no noticeable lag between my hand and the machines reaction.  Saves a
> lot of cpu cycles by not running that stuff at servo-thread rate. ISTR
> we discussed that before.
>
> I do need to change the jog mode though, I can wind it up way too easy
> and crash it, breaking tooling.  Theres a mode where it stops when I
> stop and I need to convert to that. The DRO's track whatever the
> machine does in either event if I understand it right. From man
> motion:
>
>  axis.L.jog-vel-mode IN BIT
>    When FALSE (the default), the jogwheel operates in position mode.
> The axis will move exactly jog-scale units for each count, regardless
> of how long that might take. When TRUE, the wheel operates in velocity
> mode - motion stops when the wheel stops, even if that means the
> commanded motion is not completed.
>
> The latter would be better I think. But what does that do to the size
> of the jog per click that I went to quite some length to setup? .0002"
> to 20 thou a click. ???  The theory was that I could jog right close
> to position, then reduce the jog size to almost zip and fine tune it
> to the correct size.
>
> I'll give it a shot anyway. :)
>
And I think it finally dawned on me that when calibrating the x scale on 
a lathe, that I ought to be in g8 mode when moving by a dial indicator, 
which would explain why, when I want and inch, measure the work an touch 
it off at the measurement, take a 20 thou cut to get to the target size, 
and its still 10 thou too big.

Sometimes the blindingly obvious isn't. 
:(
So I'll go recheck the x scale, it probably needs doubled.

> Thanks Peter and all.
>
> > > 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 <http://geneslinuxbox.net:6309/gene>
> > >
> > >
> > >
> > > _______________________________________________
> > > Emc-users mailing list
> > > [email protected]
> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> > Peter Wallace
> > Mesa Electronics
> >
> > (\__/)
> > (='.'=) This is Bunny. Copy and paste bunny into your
> > (")_(") signature to help him gain world domination.
> >
> >
> >
> > _______________________________________________
> > Emc-users mailing list
> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
> Cheers, Gene Heskett


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 <http://geneslinuxbox.net:6309/gene>



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