At the Hanover Fair, April 19-23 in Hanover, Germany, the Ethernet Powerlink Standardization Group (EPSG, www.ethernet-powerlink.org) demonstrated openSafety, a safety-related communication protocol that is billed as “the world’s first uniform safety standard.”
According to an April 30 press release from B&R Industrial Automation Corp. (www.br-automation.com), an Austrian-based automation components supplier with U.S. headquarters in Roswell, Ga., the EPSG, with openSafety, has now laid the foundation for the first completely open safety-related data communication protocol for all areas of automation. With communication cycles in the microsecond range, the TÜV Rhineland-certified protocol guarantees the fastest response times and highest level of safety and is suitable for use in systems rated up to SIL 4 (for Safety Integrity Level), B&R said.
Because openSafety is bus independent, it can be used with all fieldbus systems or Industrial Ethernet systems. In order to demonstrate the interoperability of the safety solution with different protocols, the EPSG presented at the 2010 Hanover event four different openSafety solutions, which were created using the most commonly implemented Industrial Ethernet protocols: SERCOS III, Modbus TCP, EtherNet/IP and Powerlink.
Users of an Industrial Ethernet system other than Powerlink for the first time now have a complete, certified safety solution available, according to B&R. Although other user organizations have been announcing the development of safety-related protocols for a long time, only the EPSG offers an operational product that runs on all transport protocols—openSafety, B&R said.
Black channel
The complete “black channel” principle of openSafety is the basis for interoperability with arbitrary transport protocols. For the functionality of the safety protocol, it doesn’t matter which transport protocol is used to transport the safety frames. That is because all safety-related mechanisms are integrated exclusively on the application layer of the protocol, and its functionality is thereby independent of the underlying transport layer. openSafety continually monitors all transferred data content to ensure that it is complete, that it has the correct transfer sequence and that the transfer duration is maintained. All transfer errors are recorded immediately so that industry-specific communication solutions and even single-channel, non-safe transport networks can be used as the basis for communication without limitations.
According to B&R, openSafety is characterized by three things: the definition of data transport using an extremely flexible telegram format, the integrated services for configuration and automatic parameter distribution, and in particular, a communication structure that achieves optimum machine productivity using cross traffic. The crucial advantage is the reduction of safety-relevant braking distances, which allows the safety margins to be ideally dimensioned and the machine cycles to be increased.
User support
The EPSG actively supports the use of openSafety with arbitrary transport protocols and offers assistance, for example, with certification and conformance tests. The openness of openSafety is valid in both technical and legal aspects: The protocol is available for free download as open source software. The BSD license and the possibility for bus-independent application guarantee everyone that uses the technology the highest investment security and allow manufacturers and plant operators to clearly reduce development times, the B&R release concluded.
B&R Industrial Automation Corp.www.br-automation.comEthernet Powerlink Standardization
Group
www.ethernet-powerlink.org
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