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<div class="moz-cite-prefix">Hi Luca,<br>
<br>
First I must say that I have just joined this list and I have not
used Etherlab.<br>
<br>
I've recently completed an EtherCAT application on an ARM based
processor (IXP420, 533MHz).<br>
<br>
Hardware specifications here:<br>
<a
href="http://www.beckhoff.com/english.asp?industrial_pc/cp66xx.htm">http://www.beckhoff.com/english.asp?industrial_pc/cp66xx.htm</a><br>
<br>
My I/O requirements were small:<br>
<ul>
<li>DI: 4</li>
<li>DO: 4</li>
<li>AI:5</li>
<li>AO:2</li>
<li>PWM: 2</li>
</ul>
I used TwinCAT for EtherCAT master.<br>
<br>
I was not able to achieve a 1 ms cycle time.<br>
<br>
A 2 ms cycle time was possible but with high real time usage and
regular cycle time exceeds in low priority tasks.<br>
<br>
In the end I had to settle on a 3 ms cycle time. This gave me
enough overhead to run lower priority tasks (such as updating the
visualisation) reliably.<br>
<br>
On the face of it, it looks like your processor runs at about half
the frequency as the one I was using, therefore it would not
surprise me if you are not able to achieve a cycle time below 4
ms.<br>
<br>
I'm not sure if this is of any relevance to you, I'm just
providing it as another point of reference.<br>
<br>
Regards, Ben<br>
<br>
<br>
On 30/08/2012 3:20 AM, <a class="moz-txt-link-abbreviated" href="mailto:paluan.luca@tiscali.it">paluan.luca@tiscali.it</a> wrote:<br>
</div>
<blockquote
cite="mid:30110664.95281346260832018.JavaMail.defaultUser@defaultHost"
type="cite">
<pre wrap="">Hello everyone,
I'm trying to develop a real time server on the arm
(arm926) cpu and on a real time linux with xenomai.
Unfortunatly even
the basic examples seem not to work on such a system: the real time
task is set to work with a 2ms period like the 2 servos connected to
the ethercat net (even though 1ms would definetly be the best).
With a
bare example I immediatly receive warning from ethercat master of
skipped frames and if the real task has to do something more the server
crashes...
I tried various compile time optimizations and I tried to
give up with real time task using hrtimer without results.
My system is
using the generic ethernet driver too, but could anyone give me some
advice about whether the cpu power is enough to manage the ethercat
driver in a real time environment?
Thanks in advance, Best Regards Luca
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</pre>
</blockquote>
<br>
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