[etherlab-users] ethercat + xenomai on arm926 cpu system

[Ben Lewis]

Hi Andreas,

My application was a complete Beckhoff solution i.e. Windows CE and TwinCAT. So no "additional" 
support from Beckoff was required.

Regards, Ben

On 30/08/2012 5:54 PM, Andreas Stewering-Bone wrote:
> Hello Ben,
>
> I see you use Beckhoff hardware,
> Did you get support or addidional information from Beckhoff to get it running.
>
> We ask for information for the CX9xxx plattform but Beckhoff does not like linux I think.
>
> Best regards
>
> Andreas
> -------- Original-Nachricht --------
>> Datum: Thu, 30 Aug 2012 09:35:28 +1000
>> Von: Ben Lewis <egretengineering at gmail.com>
>> An: etherlab-users at etherlab.org
>> Betreff: Re: [etherlab-users] ethercat + xenomai on arm926 cpu system
>> Hi Luca,
>>
>> First I must say that I have just joined this list and I have not used
>> Etherlab.
>>
>> I've recently completed an EtherCAT application on an ARM based processor
>> (IXP420, 533MHz).
>>
>> Hardware specifications here:
>> http://www.beckhoff.com/english.asp?industrial_pc/cp66xx.htm
>>
>> My I/O requirements were small:
>>
>>    * DI: 4
>>    * DO: 4
>>    * AI:5
>>    * AO:2
>>    * PWM: 2
>>
>> I used TwinCAT for EtherCAT master.
>>
>> I was not able to achieve a 1 ms cycle time.
>>
>> A 2 ms cycle time was possible but with high real time usage and regular
>> cycle time exceeds in low
>> priority tasks.
>>
>> 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.
>>
>> 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.
>>
>> I'm not sure if this is of any relevance to you, I'm just providing it as
>> another point of reference.
>>
>> Regards, Ben
>>
>>
>> On 30/08/2012 3:20 AM, paluan.luca at tiscali.it wrote:
>>> 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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