On Wednesday 07 March 2018 19:23:32 jeremy youngs wrote:

> Hello fellas ,
> I have this optiplex 2.8 GHz . I'm trying to figure if I should pitch
> it and try something else. I have reviewed the docs on latency and
> after 24 hours running I get what I think are good numbers, a Max
> jitter of 8882 and a service thread of 27405 . By comparing the given
> examples in the docs, I would think this machine would do rather well.
> It has a new Mobo , a pcie graphics card , and a pci epp card . It is
> rosewill and the graphics is an ati iirc.
> Latest bios available, no hyperthreading option, only disable multiple
> CPU core ( makes no difference)
> I have always gotten rtapi error: unexpected realtime delay on task
> one . 

I have seen that. Generally associated with the use of ati or nvidia 
closed src video drivers neither of which is allergic to shutting down 
the IRQ's when they think they are busy.. I have 2 of the optiplex 
myself.  One is a utility box I keep for programming mesa cards, the 
other is running my G0704 via a 5i25 mesa card.. The onboard video on 
both is i915, an intel video, not ati, but thats this particular pair, 
other optiplexes may not have intel video.

I've had relatively little of that sort of problems running the linux 
version of the i915 driver.

> I have my steppers set to kelling 4060? ( The only kelling 
> setting in stepconfig) these are the slowest of them all. I have
> eliminated optos . I get good performance from the machine and don't
> really want to punt. I've done the upgrades in hopes of solving the
> rtapi error. I've installed new cmos battery as well. Do I need even
> slower step settings?

Doubtfull, if the interface is wired so the + terminals are connected to 
the 5 volt buss, and a logic zero at the output then becomes the on 
signal, tied to the 4060's - terminals. It will likely run just fine on 
faster signals. The diff is that if the logic signal is tied to the + 
terminal, the pullup from the interface to turn on the opto's in the 
4060, isn't near as strong as the logic zero sinking ability. I have a 
variety of drivers, and none of them are running as slow as the choices 
in stepconfig. Set the polarity of the signals in the hal file so that 
the step signals are negative for a logic one. You may want to check 
that with a real scope.

It might be illuminating to launch "linuxcnc -lENTER" from a terminal 
screen as that will log anything suspicious to the terminal screen. 
Leave it run, preferably doing something, for half an hour, then quit 
and copy/paste the screen to another message here. That will give us an 
idea of how serious a problem you have.

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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