Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Steffen Möller]

On 01.03.22 23:35, Rod Webster wrote:

The reason why I put this on the agenda is that I observed that the debian
project uncovered a number of licenses which we had to include in our
copyright statement that deviated from the standard GPL licence. I was
quite surprised at this. I would defer to Steffen on license issues and
compatibility.

For now I think we should make contact and make those assessments later.

I propose to write requesting membership of the ETG with the following
contacts
Myself - admin contact
Lead Developer - Nicklas
Steffan - Licensing and the Debian Project.

Please let me know if that sounds OK.


It is very nice of yours to consider me but I do not think I am needed
and Debian has this rule that anything good happening to the Open Source
world must not be bound to be Debian-specific, I would hence not want to
stress Debian too much / single it out. What may be good is to have
someone EtherCAT-savvy from Germany as a helper should whatever
communication problem arise or to open some backchannel to lure them
into sponsoring our devs with some hardware.

Someone "from here" please contact Ron. Should nobody surface then
please add me as "someone local in case this is helpful". I'll PM you
contact details.

Best,
Steffen




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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[gene heskett]

On Tuesday, March 1, 2022 4:20:42 PM EST Nicklas SB Karlsson wrote:
> Den 2022-03-01 kl. 21:39, skrev Bari:
> > On 3/1/22 14:25, Nicklas SB Karlsson wrote:
> >> Den 2022-03-01 kl. 21:17, skrev Bari:
> >>> On 3/1/22 13:20, Nicklas SB Karlsson wrote:
>  Already have a simple implementation of an Ethercat driver with
>  hardcoded configuration but read something about the license
>  problem and have kept it for myself.
> >>> 
> >>> If you developed this yourself without being under an NDA or some
> >>> contract with Beckhoff aren't you free to distribute this under any
> >>> license that you choose?
> >> 
> >> Used SOEM but added some code, no NDA.
> > 
> > https://github.com/OpenEtherCATsociety/SOEM/blob/master/LICENSE
> 
> Line below seems like a problem.
> 
> 
> You can use SOEM for the sole purpose of creating, using and/or selling
> or otherwise distributing an EtherCAT network master provided that an
> EtherCAT Master License is obtained from Beckhoff Automation GmbH.
> 
I think the key word here might be "master" but check with the legal dept 
for sure.  Sounds like clients, written in a truely clean room might be 
ok. But using SOEM for advice probably isn't "clean room".

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, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 





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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Rod Webster]

The reason why I put this on the agenda is that I observed that the debian
project uncovered a number of licenses which we had to include in our
copyright statement that deviated from the standard GPL licence. I was
quite surprised at this. I would defer to Steffen on license issues and
compatibility.

For now I think we should make contact and make those assessments later.

I propose to write requesting membership of the ETG with the following
contacts
Myself - admin contact
Lead Developer - Nicklas
Steffan - Licensing and the Debian Project.

Please let me know if that sounds OK.

Rod Webster
*1300 896 832*
+61 435 765 611
Vehicle Modifications Network
www.vehiclemods.net.au


On Wed, 2 Mar 2022 at 07:48, Jérémie Tarot  wrote:

> Le mar. 1 mars 2022 à 22:22, Nicklas SB Karlsson  a écrit :
>
> >
> > >
> > > https://github.com/OpenEtherCATsociety/SOEM/blob/master/LICENSE
> >
> >
> > Line below seems like a problem.
> >
>
>
> Exactly
>
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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Jérémie Tarot]

Le mar. 1 mars 2022 à 22:22, Nicklas SB Karlsson  a écrit :

>
> >
> > https://github.com/OpenEtherCATsociety/SOEM/blob/master/LICENSE
>
>
> Line below seems like a problem.
>


Exactly

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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Nicklas SB Karlsson]

Den 2022-03-01 kl. 21:39, skrev Bari:


On 3/1/22 14:25, Nicklas SB Karlsson wrote:

Den 2022-03-01 kl. 21:17, skrev Bari:

On 3/1/22 13:20, Nicklas SB Karlsson wrote:
Already have a simple implementation of an Ethercat driver with 
hardcoded configuration but read something about the license 
problem and have kept it for myself. 



If you developed this yourself without being under an NDA or some 
contract with Beckhoff aren't you free to distribute this under any 
license that you choose?
Used SOEM but added some code, no NDA. 



https://github.com/OpenEtherCATsociety/SOEM/blob/master/LICENSE



Line below seems like a problem.


You can use SOEM for the sole purpose of creating, using and/or selling 
or otherwise distributing an EtherCAT network master provided that an 
EtherCAT Master License is obtained from Beckhoff Automation GmbH.



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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Jérémie Tarot]

Le mar. 1 mars 2022 à 21:40, Bari  a écrit :

>
>
> https://github.com/OpenEtherCATsociety/SOEM/blob/master/LICENSE



I don't understand how the last sentences could be compatible with GPL?


>

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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Bari]

On 3/1/22 14:25, Nicklas SB Karlsson wrote:

Den 2022-03-01 kl. 21:17, skrev Bari:

On 3/1/22 13:20, Nicklas SB Karlsson wrote:
Already have a simple implementation of an Ethercat driver with 
hardcoded configuration but read something about the license problem 
and have kept it for myself. 



If you developed this yourself without being under an NDA or some 
contract with Beckhoff aren't you free to distribute this under any 
license that you choose?
Used SOEM but added some code, no NDA. 



https://github.com/OpenEtherCATsociety/SOEM/blob/master/LICENSE



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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Nicklas SB Karlsson]

Den 2022-03-01 kl. 21:17, skrev Bari:

On 3/1/22 13:20, Nicklas SB Karlsson wrote:
Already have a simple implementation of an Ethercat driver with 
hardcoded configuration but read something about the license problem 
and have kept it for myself. 



If you developed this yourself without being under an NDA or some 
contract with Beckhoff aren't you free to distribute this under any 
license that you choose?

Used SOEM but added some code, no NDA.



You don't have to use their term for the driver if it is trademarked. 
Call it something else such as FreeCAT.

Renaming is simple, will do that.



The FSF has lots of resources available. Run the Beckhoff license past 
them for an opinion on conflicts with GPL.



Are there any patents involved in a Linux driver for EtherCAT?


Not sure about the driver, master use ordinary Ethernet but nodes have 
special hardware, guess is it work similar to a shift register as values 
are read/written while datagram pass thru. Pretty sure patent is about 
the nodes.



Real time perfomance is excellent and there are plenty of devices 
available to chose from on the market, Beckhoff have many.



Nickas Karlsson



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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Bari]

On 3/1/22 13:20, Nicklas SB Karlsson wrote:
Already have a simple implementation of an Ethercat driver with 
hardcoded configuration but read something about the license problem 
and have kept it for myself. 



If you developed this yourself without being under an NDA or some 
contract with Beckhoff aren't you free to distribute this under any 
license that you choose?



You don't have to use their term for the driver if it is trademarked. 
Call it something else such as FreeCAT.



The FSF has lots of resources available. Run the Beckhoff license past 
them for an opinion on conflicts with GPL.



Are there any patents involved in a Linux driver for EtherCAT?



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Re: [Emc-developers] LinuxCNC is in Debian!

[Jérémie Tarot]

Le mar. 1 mars 2022 à 18:17, andy pugh  a écrit :

>
> I am generally in favour of anything that makes LinuxCNC easier to use
> and more broadly applicable.
> So, I support bundling-in EtherCAT support, as long as we can be sure
> that nobody will be pointing their lawyers in our direction.
>


1000%

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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Steffen Möller]

On 01.03.22 20:15, Nicklas SB Karlsson wrote:

Den 2022-03-01 kl. 13:27, skrev Rod Webster:

So I shared Steffen's post on the Ethercat section of the forum
calling for
technical volunteers. Maybe some of them are in this group already.
https://forum.linuxcnc.org/ethercat/45239-lets-get-ethercat-into-the-linuxcnc-distribution-need-technical-people-to-help



I have to volunteer. Also have knowledge about CANopen which is useful
since many devices use this "protocol" over ethercat.


Great!

I'll leave it to Rod to assemble the
EtherCAT-Technology-Group-contact-front-for-LinuxCNC .

@Rod, I suggest you collect the contact details from the volunteers per
PM and finish the letter that I started or prepare a better one. As I
mentioned in my reply to Andy, we still need to learn about how to leave
that group if their conditions change so I suggest to clarify that
upfront, too. For instance, should they find LinuxCNC in violation with
anything (like proving technically incompetent, whatever) and they
cancel our membership then it is important for us that any action of
ours can only be performed "ex nunc" (from that moment on). We cannot
"undistribute" anything, which would be "ex tunc"? Gosh.

Many thanks to all!

Steffen



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Re: [Emc-developers] LinuxCNC is in Debian!

[Jérémie Tarot]

Le mar. 1 mars 2022 à 02:31, Chad Woitas  a
écrit :

>
> Exploring a few other options as well for Ethercat.
>


What about those Raspberry Pi EtherCAT HAT and Arduino EtherCAT shields?

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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Nicklas SB Karlsson]

Den 2022-02-28 kl. 15:47, skrev Steffen Möller:

Hello again,

On 28.02.22 14:28, andy pugh wrote:
On Mon, 28 Feb 2022 at 13:22, Steffen Möller  
wrote:


Personally I know nothing about EtherCAT. I have always been a little
afraid of the licensing complexities mentioned here:

https://etherlab.org/en/ethercat/

Etherlab itself is GPLv2, but _using_ it seems to bring a different
licensing restriction into play. And I don't know enough about
licensing to know if that's a problem.


I called them up - first the Beckhoff group (they have nice stuff on 
https://www.beckhoff.com/en-gb/) and from there I was pointed to the 
EtherCAT Technology Group (https://www.ethercat.org/de/contact.html), 
so I called them, too. Without that membership we would be in said 
uncharacterized unmitigated license trouble


Already have a simple implementation of an Ethercat driver with 
hardcoded configuration but read something about the license problem and 
have kept it for myself.



  that Andy referenced but with that membership they would be very 
sweet to us. From what I understand, they try to be good people and 
just in case someone messes something up they do not want to guess how 
to reach out. So we are asked to become a member of the EtherCAT 
Technology Group (ETG) - for which we would identify someone who would 
serve as a communicator between them and our community and write a 
"3-line email" with our request to integrate an EtherCAT driver that 
is available at some URL with LinuxCNC as described on 
https://linuxcnc.org.


I do not see that Debian would become a member of their Technology 
Group. And it would not make too much sense to me to have any extra 
outreach from Debian to that ETG, but we can ask for an OK to have 
that distribution channel and also ask for Fedora at the same time.


Now - big question: Is there an agreement that it would be beneficial 
for LinuxCNC to become a member of the ETG? It is free. And there 
likely a series of perks for training material that may not be of our 
immediate concern. They invited me to help with that initial contact 
but that LinuxCNC-representative to them could then be anyone we pick. 
Andy? Rod? You both? Jeff? All three of yours?

I could volunteer.


Nicklas SB Karlsson


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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Nicklas SB Karlsson]

Den 2022-03-01 kl. 13:27, skrev Rod Webster:

So I shared Steffen's post on the Ethercat section of the forum calling for
technical volunteers. Maybe some of them are in this group already.
https://forum.linuxcnc.org/ethercat/45239-lets-get-ethercat-into-the-linuxcnc-distribution-need-technical-people-to-help


I have to volunteer. Also have knowledge about CANopen which is useful 
since many devices use this "protocol" over ethercat.



Nicklas SB Karlsson



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Re: [Emc-developers] LinuxCNC is in Debian!

[Michael Graichen]

Hey Marc,

Be carefull with this. This code is running in Userspace while etherlabs 
ethercat stack is running as Kernelmodule.

Ethernet Packets in Linux are transfered to the Userspace over a mechanism 
called "Soft IRQ".
This will mess up any Realtime dependency especally on little ARMs like 
Raspberry etc if we want to do something, lets say, every millisecond.

See this link and others on the blog for details about the Linux Network Stack.

https://blog.packagecloud.io/illustrated-guide-monitoring-tuning-linux-networking-stack-receiving-data/

The network stack in Linux is realy not meant to be "realtime". There some 
other mechanisms like "packet collecting" or "pause" on heavy load because all 
was developed to defend "the server" against DOS attacks in the early days not 
for "realtime".

Beckhof actually wrote a special driver for one of there PCs that is using a 
polling mechanism to work around all those DOS defend mechanisms.

https://elixir.bootlin.com/linux/latest/source/drivers/net/ethernet/ec_bhf.c

I also enjoy this conversation.

Best regards
Michael


 Ursprüngliche Nachricht 
Von: Marc Wang 
Datum: 01.03.22 17:57 (GMT+01:00)
An: EMC developers 
Betreff: Re: [Emc-developers] LinuxCNC is in Debian!

Hi,

FYI, I got interested in the conversation and ended up finding this repository 
on GitHub:

https://github.com/OpenEtherCATsociety/SOEM

The code for the master is released as a GNU General Public License version 2.

Regards,
Marc

-Original Message-
From: Rod Webster 
Sent: March 1, 2022 7:42 AM
To: EMC developers 
Subject: Re: [Emc-developers] LinuxCNC is in Debian!

> From my understanding Beckhoff is very open regarding the master (who
>even does not need a special hardware,  when driven by an RTOS) and are
>very restrictive when it comes to the slave (where a ASIC / FPGA is
>needed in any case)

This was also my understanding when I read the licensing requirements. Heck 
they said they would even share source code with you if you were building a 
master...
I have posted on the ethercat section of the forum calling for technical guys 
to get this done 
https://forum.linuxcnc.org/ethercat/45239-lets-get-ethercat-into-the-linuxcnc-distribution-need-technical-people-to-help

Please send me an email at ether...@vmn.com.au if you can help with the tech 
stuff.

Rod Webster
*1300 896 832*
+61 435 765 611
Vehicle Modifications Network
www.vehiclemods.net.au


On Tue, 1 Mar 2022 at 21:12, Rainer Stelzer 
wrote:

> Hi Gene,
> > So once you've bought the controller, there is no other restriction.
> > And I assume that royalty is 2x per axis, once for each end of the cable.
>
> No, they don't charge twice.
> Part of marketing a Fieldbus-System is to make it widely accepted in
> the industry, so Beckhoff (and others like Siemens with Profinet)
> has/have to find a balance between protection and  easy/low cost
> accessibility.
>
>  From my understanding Beckhoff is very open regarding the master (who
> even does not need a special hardware, when driven by an RTOS) and are
> very restrictive when it comes to the slave (where a ASIC / FPGA is
> needed in any case)
>
> Makes also sense from commercial point of view, because in a typical
> system there are much more slaves needed that masters.
>
> > Or can one receiver handle more than 1 axis with acceptable latency?
>
> A slave in EtherCat's daisy chain topology has an input and an output
> Interface. (the biggest difference to most other ethernet based
> fieldbusses)
>
> The incoming stream is shifted out with 1 bit delay to the output.
>
> At 100Mbit/s -> 10ns delay added up to each slave in the chain.
>
> The difference between one slave 3axis servo pack and three single
> axis servo amps is ~20ns.
> But to synchronise the output, all slaves have to wait for the full
> frame received.
>
> Even on a 10 axis system this does not even come close to the total
> frame time.
> Not to mention the jitter caused by a (soft)RTOS
>
>
> cheers
>
> Rainer
>
>
>
>
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Re: [Emc-developers] LinuxCNC is in Debian!

[andy pugh]

On Tue, 1 Mar 2022 at 13:56, Steffen Möller  wrote:

> *My personal anchors to the community are Seb, Jeff and Andy. I suggest
> that Rod sends whatever we come up with (if we come up with anything)
> directly, but I would like to first have a positive vote by one of them
> and "don't care"s or better from them and everyone else here on the list.*

I am generally in favour of anything that makes LinuxCNC easier to use
and more broadly applicable.
So, I support bundling-in EtherCAT support, as long as we can be sure
that nobody will be pointing their lawyers in our direction.

However, one worry that we had in the past was that, whilst this
organisation might be inside the Beckhoff "rules" if we join ETG,
doing so might accidentally impose an unexpected (by them) licensing
condition or restriction on our users.
I don't know how real a worry that is.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-developers] LinuxCNC is in Debian!

[Marc Wang]

Hi, 

FYI, I got interested in the conversation and ended up finding this repository 
on GitHub:

https://github.com/OpenEtherCATsociety/SOEM

The code for the master is released as a GNU General Public License version 2. 

Regards,
Marc

-Original Message-
From: Rod Webster  
Sent: March 1, 2022 7:42 AM
To: EMC developers 
Subject: Re: [Emc-developers] LinuxCNC is in Debian!

> From my understanding Beckhoff is very open regarding the master (who  
>even does not need a special hardware,  when driven by an RTOS) and are 
>very restrictive when it comes to the slave (where a ASIC / FPGA is 
>needed in any case)

This was also my understanding when I read the licensing requirements. Heck 
they said they would even share source code with you if you were building a 
master...
I have posted on the ethercat section of the forum calling for technical guys 
to get this done 
https://forum.linuxcnc.org/ethercat/45239-lets-get-ethercat-into-the-linuxcnc-distribution-need-technical-people-to-help

Please send me an email at ether...@vmn.com.au if you can help with the tech 
stuff.

Rod Webster
*1300 896 832*
+61 435 765 611
Vehicle Modifications Network
www.vehiclemods.net.au


On Tue, 1 Mar 2022 at 21:12, Rainer Stelzer 
wrote:

> Hi Gene,
> > So once you've bought the controller, there is no other restriction. 
> > And I assume that royalty is 2x per axis, once for each end of the cable.
>
> No, they don't charge twice.
> Part of marketing a Fieldbus-System is to make it widely accepted in 
> the industry, so Beckhoff (and others like Siemens with Profinet) 
> has/have to find a balance between protection and  easy/low cost 
> accessibility.
>
>  From my understanding Beckhoff is very open regarding the master (who 
> even does not need a special hardware, when driven by an RTOS) and are 
> very restrictive when it comes to the slave (where a ASIC / FPGA is 
> needed in any case)
>
> Makes also sense from commercial point of view, because in a typical 
> system there are much more slaves needed that masters.
>
> > Or can one receiver handle more than 1 axis with acceptable latency?
>
> A slave in EtherCat's daisy chain topology has an input and an output 
> Interface. (the biggest difference to most other ethernet based
> fieldbusses)
>
> The incoming stream is shifted out with 1 bit delay to the output.
>
> At 100Mbit/s -> 10ns delay added up to each slave in the chain.
>
> The difference between one slave 3axis servo pack and three single 
> axis servo amps is ~20ns.
> But to synchronise the output, all slaves have to wait for the full 
> frame received.
>
> Even on a 10 axis system this does not even come close to the total 
> frame time.
> Not to mention the jitter caused by a (soft)RTOS
>
>
> cheers
>
> Rainer
>
>
>
>
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Re: [Emc-developers] LinuxCNC is in Debian!

[Rod Webster]

> From my understanding Beckhoff is very open regarding the master (who
> even does not need a special hardware,
> when driven by an RTOS) and are very restrictive when it comes to the
>slave (where a ASIC / FPGA is needed in any case)

This was also my understanding when I read the licensing requirements. Heck
they said they would even share source code with you if you were building a
master...
I have posted on the ethercat section of the forum calling for technical
guys to get this done
https://forum.linuxcnc.org/ethercat/45239-lets-get-ethercat-into-the-linuxcnc-distribution-need-technical-people-to-help

Please send me an email at ether...@vmn.com.au if you can help with the
tech stuff.

Rod Webster
*1300 896 832*
+61 435 765 611
Vehicle Modifications Network
www.vehiclemods.net.au


On Tue, 1 Mar 2022 at 21:12, Rainer Stelzer 
wrote:

> Hi Gene,
> > So once you've bought the controller, there is no other restriction. And
> > I assume that royalty is 2x per axis, once for each end of the cable.
>
> No, they don't charge twice.
> Part of marketing a Fieldbus-System is to make it widely accepted in the
> industry, so Beckhoff
> (and others like Siemens with Profinet) has/have to find a balance
> between protection and  easy/low cost accessibility.
>
>  From my understanding Beckhoff is very open regarding the master (who
> even does not need a special hardware,
> when driven by an RTOS) and are very restrictive when it comes to the
> slave (where a ASIC / FPGA is needed in any case)
>
> Makes also sense from commercial point of view, because in a typical
> system there are much more slaves needed that masters.
>
> > Or can one receiver handle more than 1 axis with acceptable latency?
>
> A slave in EtherCat's daisy chain topology has an input and an output
> Interface. (the biggest difference to most other ethernet based
> fieldbusses)
>
> The incoming stream is shifted out with 1 bit delay to the output.
>
> At 100Mbit/s -> 10ns delay added up to each slave in the chain.
>
> The difference between one slave 3axis servo pack and three single axis
> servo amps is ~20ns.
> But to synchronise the output, all slaves have to wait for the full
> frame received.
>
> Even on a 10 axis system this does not even come close to the total
> frame time.
> Not to mention the jitter caused by a (soft)RTOS
>
>
> cheers
>
> Rainer
>
>
>
>
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Re: [Emc-developers] EtherCAT - would not be a prob with free membership in EtherCAT Technology Group Re: LinuxCNC is in Debian!

[Rod Webster]

So I shared Steffen's post on the Ethercat section of the forum calling for
technical volunteers. Maybe some of them are in this group already.
https://forum.linuxcnc.org/ethercat/45239-lets-get-ethercat-into-the-linuxcnc-distribution-need-technical-people-to-help

Lets hope the right people come forward.

Rod Webster
*1300 896 832*
+61 435 765 611
Vehicle Modifications Network
www.vehiclemods.net.au


On Tue, 1 Mar 2022 at 07:44, Rod Webster  wrote:

> One could argue we are already in breach of their license by mentioning
> Ethercat in our Debian package :)
> There is no point suggesting something without being willing to contribute.
> Therefore I am happy to be an admin contact using the email
> ether...@vmn.com.au
> There are others who are more competent than I with the technical stuff.
>
> Sascha Ittner and Dominik Braun whose work on github I referenced spring
> to mind
> Also Arvid Brodin who is in this group knows a bit I think but is working
> on trajectory planning
> Michel Winja (Grotius) is also very knowledgeable
>
> I will see if I can attract their attention.
>
> Rod Webster
> *1300 896 832*
> +61 435 765 611
> Vehicle Modifications Network
> www.vehiclemods.net.au
>
>
> On Tue, 1 Mar 2022 at 00:48, Steffen Möller 
> wrote:
>
>> Hello again,
>>
>> On 28.02.22 14:28, andy pugh wrote:
>> > On Mon, 28 Feb 2022 at 13:22, Steffen Möller 
>> wrote:
>> >
>> > Personally I know nothing about EtherCAT. I have always been a little
>> > afraid of the licensing complexities mentioned here:
>> >
>> > https://etherlab.org/en/ethercat/
>> >
>> > Etherlab itself is GPLv2, but _using_ it seems to bring a different
>> > licensing restriction into play. And I don't know enough about
>> > licensing to know if that's a problem.
>>
>> I called them up - first the Beckhoff group (they have nice stuff on
>> https://www.beckhoff.com/en-gb/) and from there I was pointed to the
>> EtherCAT Technology Group (https://www.ethercat.org/de/contact.html), so
>> I called them, too. Without that membership we would be in said
>> uncharacterized unmitigated license trouble  that Andy referenced but with
>> that membership they would be very sweet to us. From what I understand,
>> they try to be good people and just in case someone messes something up
>> they do not want to guess how to reach out. So we are asked to become a
>> member of the EtherCAT Technology Group (ETG) - for which we would identify
>> someone who would serve as a communicator between them and our community
>> and write a "3-line email" with our request to integrate an EtherCAT driver
>> that is available at some URL with LinuxCNC as described on
>> https://linuxcnc.org.
>>
>> I do not see that Debian would become a member of their Technology Group.
>> And it would not make too much sense to me to have any extra outreach from
>> Debian to that ETG, but we can ask for an OK to have that distribution
>> channel and also ask for Fedora at the same time.
>>
>> Now - big question: Is there an agreement that it would be beneficial for
>> LinuxCNC to become a member of the ETG? It is free. And there likely a
>> series of perks for training material that may not be of our immediate
>> concern. They invited me to help with that initial contact but that
>> LinuxCNC-representative to them could then be anyone we pick. Andy? Rod?
>> You both? Jeff? All three of yours?
>>
>> Best,
>> Steffen
>>
>>
>>
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>

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Re: [Emc-developers] LinuxCNC is in Debian!

[Steffen Möller]

On 01.03.22 10:59, Les Newell wrote:



So once you've bought the controller, there is no other restriction.


As far as I can tell from their docs, that is the case. It's a pretty
sound business model.


I assume that royalty is 2x per axis, once for each end of the cable.


From what I can tell, it would be one royalty per axis. Daisy chaining
is part of the hardware spec.



The industry pays such patent taxes to microsoft/google/... about
everywhere. I am relaxed about that since all we want to have is an open
source access to use these devices. Here an idea for the three lines,
now asking for membership as the operational action to allow us to
redistribute whatever Open Source drivers there are through whatever
channel. I am starting with an introduction since my two contacts did
not know who we are and it is somewhat polite :)

I started some text on
https://docs.google.com/document/d/1LFtgxDwE2tQRFjFGu_AAlBCuqBEoW6CaXoSWiaJrFkM/edit?usp=sharing
. Send me an email address that Google is allowed to see for direct
editing (only comments via the link). Here what I came up with so far:

*

Sehr geehrte Damen und Herren, [their office is in Germany, I prefer
this over Dear Madam/SIr or To whom this may concern, but direct me]

We contact you in the name of the LinuxCNC community to investigate how
we could integrate public EtherCAT drivers with our software
infrastructure. We are a 20+ years Open Source project to control CNC
machines that has found frequent adoptions also to control a diverse set
of robots up to 9 axes. LinuxCNC interprets G-code and some like to
program their hardware directly with it. Please find use cases and our
documentation on https://linuxcnc.org or YouTube.

Since Open Source, and with a nice hardware abstraction layer, LinuxCNC
is commonly used by enthusiasts with access to machines from the late
1900s to retrofit these with modern technology. And others take modern
parts home to explain their dayjob to their kids or to edutain
themselves as a hobby. That spirit prevails to bring LinuxCNC to
whatever is existing, and extend LinuxCNC when it encounters something new.

A few days ago, LinuxCNC became a regular package of Debian Linux and
will soon also be on Ubuntu. Works on Fedora (the free companion to
RedHat) are on their way. No hardware projects are performed within
LinuxCNC, but we would like to be complete when it comes to software
compatibility, just like you expect Linux to run everywhere. Upstream we
look at CAD/CAM, and downstream, it is the communication from the Linux
machine to the servos and steppers, that is you.

We understand that EtherCAT has a “GPL-2 if you OKed it and make us an
ETG-member”-license, which we do not understand and did not find more
information about. As a community, we decided not to preoccupy ourselves
with the legal details, we are all techies after all, if you could give
us such a membership-carte-blanche to create, modify and redistribute
EtherCAT drivers directly via our website and/or via Linux Distributions
(Fedora, Debian, OpenSuSE and its derivative distributions). All our
developments/modifications will be Open Source and once available via
regular Linux distributions this will lower the setup costs for your
existing and new members.

We have a technical coordinator of this effort with access to a series
of EtherCAT devices

and these developers who feel associated with the project

, … , 

who agreed that you may contact them. If there are other members in the
ETG with an interest in combining LinuxCNC with EtherCAT then we would
very much like to get in touch with them.

*

*Looking forward to a fruitful collaboration*

*Rod in the name of the LinuxCNC community
*

*
*

*My personal anchors to the community are Seb, Jeff and Andy. I suggest
that Rod sends whatever we come up with (if we come up with anything)
directly, but I would like to first have a positive vote by one of them
and "don't care"s or better from them and everyone else here on the list.*

*Best,
Steffen
*

*
*


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Re: [Emc-developers] LinuxCNC is in Debian!

[gene heskett]

On Tuesday, March 1, 2022 5:29:51 AM EST Rainer Stelzer wrote:
> Hi Gene,
> 
> > So once you've bought the controller, there is no other restriction.
> > And I assume that royalty is 2x per axis, once for each end of the
> > cable.
> No, they don't charge twice.
> Part of marketing a Fieldbus-System is to make it widely accepted in
> the industry, so Beckhoff
> (and others like Siemens with Profinet) has/have to find a balance
> between protection and  easy/low cost accessibility.
> 
>  From my understanding Beckhoff is very open regarding the master (who
> even does not need a special hardware,
> when driven by an RTOS) and are very restrictive when it comes to the
> slave (where a ASIC / FPGA is needed in any case)
> 
> Makes also sense from commercial point of view, because in a typical
> system there are much more slaves needed that masters.
> 
> > Or can one receiver handle more than 1 axis with acceptable latency?
> 
> A slave in EtherCat's daisy chain topology has an input and an output
> Interface. (the biggest difference to most other ethernet based
> fieldbusses)
> 
> The incoming stream is shifted out with 1 bit delay to the output.
> 
> At 100Mbit/s -> 10ns delay added up to each slave in the chain.
> 
> The difference between one slave 3axis servo pack and three single axis
> servo amps is ~20ns.
> But to synchronise the output, all slaves have to wait for the full
> frame received.
> 
> Even on a 10 axis system this does not even come close to the total
> frame time.
> Not to mention the jitter caused by a (soft)RTOS
> 
Which is usually much higher than that. 20ns doesn't even register on my 
rpi4 with its 12 u-secs of jitter. And that runs my 11x54 Sheldon like 
Casper the ghost with its new 3 phase stepper/servo's. Its eirie watching 
it move dead silently at normal cutting speeds.

> cheers
> 
> Rainer
 
Thanks Rainer.

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, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 





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Re: [Emc-developers] LinuxCNC is in Debian!

[Rainer Stelzer]

Hi Gene,

So once you've bought the controller, there is no other restriction. And
I assume that royalty is 2x per axis, once for each end of the cable.


No, they don't charge twice.
Part of marketing a Fieldbus-System is to make it widely accepted in the 
industry, so Beckhoff
(and others like Siemens with Profinet) has/have to find a balance 
between protection and  easy/low cost accessibility.


From my understanding Beckhoff is very open regarding the master (who 
even does not need a special hardware,
when driven by an RTOS) and are very restrictive when it comes to the 
slave (where a ASIC / FPGA is needed in any case)


Makes also sense from commercial point of view, because in a typical 
system there are much more slaves needed that masters.



Or can one receiver handle more than 1 axis with acceptable latency?


A slave in EtherCat's daisy chain topology has an input and an output 
Interface. (the biggest difference to most other ethernet based fieldbusses)


The incoming stream is shifted out with 1 bit delay to the output.

At 100Mbit/s -> 10ns delay added up to each slave in the chain.

The difference between one slave 3axis servo pack and three single axis 
servo amps is ~20ns.
But to synchronise the output, all slaves have to wait for the full 
frame received.


Even on a 10 axis system this does not even come close to the total 
frame time.

Not to mention the jitter caused by a (soft)RTOS


cheers

Rainer




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Re: [Emc-developers] LinuxCNC is in Debian!

[Les Newell]

So once you've bought the controller, there is no other restriction.


As far as I can tell from their docs, that is the case. It's a pretty 
sound business model.



I assume that royalty is 2x per axis, once for each end of the cable.


From what I can tell, it would be one royalty per axis. Daisy chaining 
is part of the hardware spec.



That no doubt makes the cheese more binding.  Or can one receiver handle
more than 1 axis with acceptable latency?


At the end of the day it's just a communications protocol. What you send 
down it is up to you. Ethernet has a pretty high bandwidth so you can 
stuff quite a lot down there before latency becomes an issue.


Les



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Re: [Emc-developers] LinuxCNC is in Debian!

[gene heskett]

On Tuesday, March 1, 2022 4:27:21 AM EST Les Newell wrote:
> > I was not specificaly seeking the monetary cost, more the loss of
> > rights, which could be far more costly than the monetary cost. As
> > always, keep TANSTAAFL in mind.
> 
> As far as Beckhoff are concerned this isn't a free lunch. Similar to
> Mesa they make their money on the hardware. Supporting the software is
> simply a cost of doing business.
> 
> Obviously they sell their own hardware but they also charge a royalty
> fee for every Ethercat slave device manufactured. For instance
> Microchip sell Ethercat device controllers. For each controller chip
> they sell, they pay a royalty to Beckhoff.
> 
> Les

So once you've bought the controller, there is no other restriction.  And 
I assume that royalty is 2x per axis, once for each end of the cable. 
That no doubt makes the cheese more binding.  Or can one receiver handle 
more than 1 axis with acceptable latency?

Thanks Les, take care & stay well.

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, 1940)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 





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Re: [Emc-developers] LinuxCNC is in Debian!

[Les Newell]

I was not specificaly seeking the monetary cost, more the loss of rights,
which could be far more costly than the monetary cost. As always, keep
TANSTAAFL in mind.


As far as Beckhoff are concerned this isn't a free lunch. Similar to 
Mesa they make their money on the hardware. Supporting the software is 
simply a cost of doing business.


Obviously they sell their own hardware but they also charge a royalty 
fee for every Ethercat slave device manufactured. For instance Microchip 
sell Ethercat device controllers. For each controller chip they sell, 
they pay a royalty to Beckhoff.


Les



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