On Fri, 28 Feb 2014, Gene Heskett wrote:
> Date: Fri, 28 Feb 2014 15:53:59 -0500
> From: Gene Heskett <[email protected]>
> Reply-To: EMC developers <[email protected]>
> To: [email protected]
> Subject: Re: [Emc-developers] gentoo distro
>
> On Friday 28 February 2014 15:02:37 Peter C. Wallace did opine:
>
>> On Fri, 28 Feb 2014, Jon Elson wrote:
>>> Date: Fri, 28 Feb 2014 11:03:38 -0600
>>> From: Jon Elson <[email protected]>
>>> Reply-To: EMC developers <[email protected]>
>>> To: EMC developers <[email protected]>
>>> Subject: Re: [Emc-developers] gentoo distro
>>>
>>> On 02/28/2014 06:24 AM, andy pugh wrote:
>>>> On 27 February 2014 15:22, bari 00000 <[email protected]> wrote:
>>>>> He's mostly working on porting RTAI to ARM
>>>>
>>>> What is the motivation for this? Xenomai works on ARM already, and
>>>> appears to work.
>>>
>>> Right, the only real need for RTAI might be for software
>>> generated
>>> steps, and that has already been tacked FAR better by the PRU
>>> code by Charles. For any hardware-assisted system, it looks
>>> like Xenomai will do OK.
>>>
>>> Jon
>>
>> I think there may well be a place for RTAI on ARM for high performance
>> embedded LinuxCNC systems (Think 10 KHz or > servo thread)
>
> Somehow, and I am probably not thinking it thru, that seems like so much
> overkill. That said, I found that with all the encoder stuff to handle in
> the .hal, the noise level of the encoders velocity pin, used for spindle
> speed control, dropped an order of magnitude when I set both SERVO_THREAD
> and TRAJECTORY_THREAD to 2khz with an = 500000 in the .ini file. Going back
> to the std 1000000 for both, makes the encoder output so noisy in the x4
> mode as to be not nearly so usable due to the amount of low pass lag needed
> to filter the noise. BASE_THREAD is currently at 25000 and I haven't seen
> a realtime delay message in months. And this is working well on an atom
> board with a (currently) 278 line .hal file.
Anything fast and precise benefits from higher loop rates. As embedded
hardware that runs Linxcnc gets better, its good not to limit the thread rate
with excessive latency so I think RTAI still has its place.
Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.
------------------------------------------------------------------------------
Flow-based real-time traffic analytics software. Cisco certified tool.
Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer
Customize your own dashboards, set traffic alerts and generate reports.
Network behavioral analysis & security monitoring. All-in-one tool.
http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk
_______________________________________________
Emc-developers mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-developers
