Status, rights and licensing
Which is the legal status of the various user organizations? Who owns the technology? Which legal ties, depending on the licensing regime, are binding for developers who use a specific technology? The following pages provide an overview.
EtherCAT Technology Group: the non-registered club is not a legal entity, but is effectively a hybrid between an association and a private partnership, for which legal liabilities remain unclear.
In most cases, the rights to a technology rest with the organization responsible for it. As co-owners, members are therefore entitled to make use of it. If other persons or companies own the rights to a technology, the prospects for future legal use of it remain unclear.
Membership in the ETG is free of charge. A fee is due for memberships in all other organizations. Annual contributions usually vary with the size of a corporate member. POWERLINK‘s and sercos‘ user organizations also allow non-members to develop products and put them on the market.
While communication mechanisms are specified for SERCOS III and EtherCAT, the inner workings of a slave remain undisclosed. Users must resort to an ASIC or an FPGA. FPGA IP code from Beckhoff is available for EtherCAT as object code, the source code is not disclosed.
PROFINET : The PROFIBUS user organization (PNO) provides source code and documentations for PROFINET implementations (PROFINET runtime software) to its members. Clause 1.5 of the license agreement for this software gives PNO members the right to use five patents.
POWERLINK : POWERLINK master and slave code is freely available under a BSD open source license. The software stack is available on SourceForge.net.
EtherNet/IP: Stacks are available for purchase from various service providers. An open source variant has been developed by a university.
EtherCAT : Slave implementations necessarily require an ASIC or an FPGA. The VHDL or IP code for the FPGA must be purchased from Beckhoff; no source code for it is available. The ETG provides sample source code for the master side. Since the patent holder has not agreed to an open source licensing regime, that source code does not qualify as open source.*
SERCOS III : Software master is provided free of charge under an LGPL license. ASICs or FPGA code must be purchased for the slave.
* Source: Open Source Automation Development Lab (www.osadl.org)