[Xenomai] Xenomai, rtnet and ethercat

[Xenomai] Xenomai, rtnet and ethercat

[Franz Engel]

Hi,

I have to connect my realtime xenomai system with an lasertracker. The tracker is using ethercat. Has somebody experiences to do this? I would like to use rtnet as realtime stack. Is it possible to use an ethercat master with rtnet driver? Or is there a realtime ethercat master available?

I found the following Ethercat projects (but I think they have no ethercat capables):
http://soem.berlios.de/
http://etherlab.org/en/ethercat/index.php

Thanks and regards,
     Franz

Re: [Xenomai] Xenomai, rtnet and ethercat

[Anders Blomdell]

On 05/25/2013 12:57 PM, Franz Engel wrote:
> Hi,
>
> I have to connect my realtime xenomai system with an lasertracker. The tracker is using ethercat. Has somebody experiences to do this? I would like to use rtnet as realtime stack. Is it possible to use an ethercat master with rtnet driver? Or is there a realtime ethercat master available?
>
> I found the following Ethercat projects (but I think they have no ethercat capables):
> http://soem.berlios.de/
> http://etherlab.org/en/ethercat/index.php

Read the licensing terms carefully, last time I looked, the EtherCAT 
license was not compatible with open licenses like GPL (see 
https://mail.gna.org/public/xenomai-help/2009-10/msg00074.html)


Regards

Anders Blomdell

Re: [Xenomai] Xenomai, rtnet and ethercat

[Leopold Palomo Avellaneda]

A Dissabte, 25 de maig de 2013, Anders Blomdell va escriure:
> On 05/25/2013 12:57 PM, Franz Engel wrote:
> > Hi,
> > 
> > I have to connect my realtime xenomai system with an lasertracker. The
> > tracker is using ethercat. Has somebody experiences to do this? I would
> > like to use rtnet as realtime stack. Is it possible to use an ethercat
> > master with rtnet driver? Or is there a realtime ethercat master
> > available?
> > 
> > I found the following Ethercat projects (but I think they have no
> > ethercat capables): http://soem.berlios.de/
> > http://etherlab.org/en/ethercat/index.php
> 
> Read the licensing terms carefully, last time I looked, the EtherCAT
> license was not compatible with open licenses like GPL (see
> https://mail.gna.org/public/xenomai-help/2009-10/msg00074.html)
> 

I'm not a lawyer and I cannot make an opinion about that. I have read a lot 
about ethercat, and its license and I have to admit that it's a bit of mess. 

My recommendation is that if you don't want to make a commercial product, or 
sell your software, you can use any of the two  ethercat master: soem and 
etherlab. I don't think that Beckhoff makes you problems. If you want to do any 
commercial product, ask to Beckoff first.

About your question, etherlab provides a ethercat master under xenomai or 
rtai. You have a limited options of drivers with both, but realtime 
capabilities.

Etherlab provides also ethercat master with standard kernel drivers with 
PREMPT_RT, so you could have a softrealtime with any NIC supported by the 
kernel.

Soem provides also ethercat master, but it doesn't provides officially support 
under xenomai (or rtai). You must use any standard driver and could work under 
PREMPT_RT. 

The orocos developers have a version of soem that works with rtnet, but it has 
not been worked quit well for us, so by now, I cannot recommend it. However, I 
have to say that I have to review it because it has been changed a lot.

We have use soem with an standard ethernet driver and xenomai and we have been 
able to communicate with or servos at 1 ms.

Hope it helps.

Regards,

Leopold








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Re: [Xenomai] Xenomai, rtnet and ethercat

[Wolfgang Denk]

Dear Leopold Palomo Avellaneda,

In message <201305260224.59809.leo@alaxarxa.net> you wrote:
>
> My recommendation is that if you don't want to make a commercial product, or 
> sell your software, you can use any of the two  ethercat master: soem and 
> etherlab. I don't think that Beckhoff makes you problems. If you want to do any 
> commercial product, ask to Beckoff first.

The license terms make no such difference. As soon as you distribute
any such system (no matter if commercial or otherwise, even for free)
you are violating the terms.


Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
A fanatic is a person who can't change his mind and won't change  the
subject.                                          - Winston Churchill

Re: [Xenomai] Xenomai, rtnet and ethercat

[Anders Blomdell]

On 2013-05-26 09:00, Wolfgang Denk wrote:
> Dear Leopold Palomo Avellaneda,
>
> In message <201305260224.59809.leo@alaxarxa.net> you wrote:
>>
>> My recommendation is that if you don't want to make a commercial product, or
>> sell your software, you can use any of the two  ethercat master: soem and
>> etherlab. I don't think that Beckhoff makes you problems. If you want to do any
>> commercial product, ask to Beckoff first.
>
> The license terms make no such difference. As soon as you distribute
> any such system (no matter if commercial or otherwise, even for free)
> you are violating the terms.
>

It's even worse than that, you are not even allowed to use it internally 
without signing the EtherCAT license. At 2007 when ethercat.org was 
still stating that EtherCAT was GPL compatible/friendly, we wrote an 
EtherCAT master in realtime Java ([1], [2]). After having completed that 
when we were about to release it to the world, we were told by Beckhoff 
that in order to distribute or use it (even internal use!), we had to 
sign the Beckhoff license (hence that project was scrapped!). The GPL 
wording was also removed from the EtherCAT site at this time (the whole 
process of triyng to get the licensing right took almost two year, after 
this time we finally got an answer from Gerd Hoppe [3]).



Regards

Anders


[1] 
http://fileadmin.cs.lth.se/cs/Personal/Sven_Gestegard_Robertz/publ/jtres-flexpicker.pdf

[2] http://youtu.be/xH1yUXd9krU?t=3m47s

[3] Excerpt from email 2009-04-08:

"Therefore, any use of EtherCAT requires a license in addition to a 
copyright license for code such as L/GPL, regardless of any split of 
code in a licensed part and a L/GPL part."

-- 
Anders Blomdell                  Email: anders.blomdell@control.lth.se
Department of Automatic Control
Lund University                  Phone:    +46 46 222 4625
P.O. Box 118                     Fax:      +46 46 138118
SE-221 00 Lund, Sweden

Re: [Xenomai] Xenomai, rtnet and ethercat

[Leopold Palomo-Avellaneda]

A Dilluns, 27 de maig de 2013, Anders Blomdell va escriure:
> On 2013-05-26 09:00, Wolfgang Denk wrote:
> > Dear Leopold Palomo Avellaneda,
> >
> > In message <201305260224.59809.leo@alaxarxa.net> you wrote:
> >>
> >> My recommendation is that if you don't want to make a commercial product, 
or
> >> sell your software, you can use any of the two  ethercat master: soem and
> >> etherlab. I don't think that Beckhoff makes you problems. If you want to 
do any
> >> commercial product, ask to Beckoff first.
> >
> > The license terms make no such difference. As soon as you distribute
> > any such system (no matter if commercial or otherwise, even for free)
> > you are violating the terms.
> >
> 
> It's even worse than that, you are not even allowed to use it internally 
> without signing the EtherCAT license. At 2007 when ethercat.org was 
> still stating that EtherCAT was GPL compatible/friendly, we wrote an 
> EtherCAT master in realtime Java ([1], [2]). After having completed that 
> when we were about to release it to the world, we were told by Beckhoff 
> that in order to distribute or use it (even internal use!), we had to 
> sign the Beckhoff license (hence that project was scrapped!). The GPL 
> wording was also removed from the EtherCAT site at this time (the whole 
> process of triyng to get the licensing right took almost two year, after 
> this time we finally got an answer from Gerd Hoppe [3]).
> 

this is sad ... 

in ethercat.org theres a point in the FAQ:

from there:
http://www.ethercat.org/en/faq.html#790

--------------------------------------------------------
3.4 How about Open Source? 

EtherCAT technology itself is not Open Source. Backed by the standardization 
of EtherCAT by IEC, ISO and SEMI, access to EtherCAT technology is available 
to everyone to non-discriminatory terms. Additionally, Master Licenses are 
free of royalties. Maintenance and all further development of the technology 
is available to all users by membership within the ETG, the user group for 
EtherCAT technology. If you have questions regarding implementing or using 
EtherCAT in conjunction with shared source or open source systems please 
contact ETG headquarters or Beckhoff, the EtherCAT technology licensor.
--------------------------------------------------------

I have asked, so when I got the answer I will inform.

regards,

Leopold

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