Leopold Palomo Avellaneda wrote: > A Dimarts 04 Novembre 2008, Jan Kiszka va escriure: >> Leopold Palomo-Avellaneda wrote: >>> Dear people, >>> >>> I don't know if this is an off topic but I would like to ask about it to >>> the list if someone could clarify my ideas. >>> >>> We are thinking to buy a rail to put our industrial robot. This rail will >>> be controller by a servo. We have looking on the market, and there are >>> some technologies to control via ethernet devices. >>> >>> I have looked only the "open" and the manufacturers offers me a protocol >>> called ethercat, who claims to be open source and gpl, but it has a >>> conflict with the licenses. >> ...which should be resolved at some (hopefully) near point in the future. > > but someone is working on this? > do you know if someone of fsf is looking on it?
FMTC and Beckhoff people are said to work on resolving the issue. I don't know any details nor news, but someone just asked again for an update on ethercatmaster-users. > >>> Powerlink, but I have understood that someone in the list >>> have no good opinion. >> ??? > > :-) > >> There is no [L]GPL'ed stacked for Powerlink yet, but at least some >> BSD-licensed code. > > well, there are some the code, bsd licensed. Are you saying that there is > a functional code? Well, probably I didn't understand the answer. I haven't looked into details, but they claim its functional. And as long as the stack can live in user land, the otherwise unfortunate license should also be no problem. But I think to recall that they also had kernel bits. > > >>> So, someone knows if exists industrial devices that could be controlled >>> by rtnet? or someone could give some opinion about all this mess of >>> "open" protocols? >> RTnet is not directly comparable to "full-blown" industrial RT Ethernet >> approaches. RTnet is an open stack that can even be used to implement >> some of those protocols. > So, someone could implement this kind of protocols "over" rtnet, no? As far as no special requirements (e.g. too demanding timing for a GPOS/RTOS system) prevents it, yes. One example is EthercatMaster over RTnet. > >> But it does not come with its own abstraction >> of industrial devices (drives, I/O clamps etc.). Ie. there are no >> "RTnet-compliant" industrial device definable due to this undefined >> highest layer (industrial applications). > > Have you think about it? To promote some kind of standard protocol for > industrial using rtnet? Defining and promoting such a protocol takes orders of magnitude more time than a single person can spent. :) Seriously, such things requires a broad user base that wants to drive it or simply contribute to it. > >> If your task is to attach industrial devices that talk a fixed protocol >> (or set of protocols), those will dictate the wire. > > Sure, but for example now I can choose if I buy a canbus card or use a > ethernet card. The manufacturer offers the two options. The interesting question is, which protocol they speak over these commodity media, and if you can find (ideally) open sourced implementations for them. > >> But that may still >> allow to implement the "intelligent" nodes based on RTnet+<high-level >> protocol> under Linux. > > but still the problem is communicate with the industrial device. > > Thanks for the answer. > > Regards, > > Leo > Jan
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