openSAFETY

openSAFETY is a communication protocol for the transmission of safety-relevant data when operating machines and other technical equipment in industrial production , in process systems or in similar areas. In the case of such safety data, B. to be alarm signals that were triggered by someone or something getting into beams of light barriers that are supposed to protect against accidents in a danger area. While conventional solutions for the transmission of such signals use special cables between the protective devices on site and control systems, which are connected via special relays , openSAFETY allows the transmission of safety information without cables laid specially for this type of data. This is possible because openSAFETY is a bus- based protocol with which safety data can be transmitted via existing industrial Ethernet cables. The security protocol also uses Ethernet networks that were originally installed for general monitoring and control tasks and are still used primarily for these purposes. In contrast to other bus-compatible safety protocols, which only work with one or a few specific Industrial Ethernet implementations and are not compatible with other systems , openSAFETY can be used with a large number of different Industrial Ethernet variants.

Certification and functional features

openSAFETY is certified according to the IEC 61508 standard and meets the requirements for applications in accordance with SIL 3. The protocol has been tested by the national IEC committees in a good two dozen countries, approved as part of IEC 61784-3 FSCP 13 and released for international standardization.

openSAFETY supports functions for optimized data transmission, in particular direct cross-traffic between network participants, i.e. communication from end device to end device without going through special control units. In addition, it offers a number of precautions to guarantee the integrity and freedom from errors of transmitted data, such as time stamps, unique identifiers for data packets and others. The protocol encapsulates safety data within a standard Ethernet frame. An openSAFETY frame always consists of two subframes, which are identical copies of each other. Each of the subframes contains its own CRC checksum . The multiple backups and redundancy on several levels achieved in this way prevent corruption of security data and other types of errors from occurring unnoticed.

Interoperability and open source license

In contrast to bus-based safety solutions that were already available in the past, each of which serves as a safety supplement to a special Industrial Ethernet protocol or a specific protocol family, openSAFETY is geared towards general interoperability. In addition, openSAFETY was made available under a BSD license ; it is therefore open-source , while the other bus-based security solutions such as B. PROFIsafe , Safety over EtherCAT or CIP Safety are proprietary technologies.

The safety solution that has now been incorporated into openSAFETY was originally developed by the Ethernet POWERLINK Standardization Group (EPSG) as a safety supplement especially for the Powerlink Industrial Ethernet variant supported by this user organization . This predecessor to openSAFETY was introduced in 2007 under the name POWERLINK Safety. The further developed and now open source protocol is no longer bound to POWERLINK. Instead, it can be used with a number of different important Industrial Ethernet implementations, specifically in addition to POWERLINK also with Profinet , SERCOS III , EtherNet / IP or Modbus-TCP . This broad interoperability with approx. 90% of the Industrial Ethernet networks installed worldwide in 2010 is achieved because openSAFETY only works on the top (application) communication layer of the network. For the transmission of safety data on this layer, the different characteristics of different protocol variants on lower network levels do not represent any significant restrictions. This approach is also known as the black channel principle for communication protocols .

Technology demonstration in 2010 and developments since then

openSAFETY has been available as an open source protocol since 2009. The protocol is therefore still a young technology among bus-based security solutions.

The open system attracted a lot of attention at the Hanover Industry Fair in April 2010, as four different, functional implementations of the safety solution were shown at the openSAFETY presentation there, which ran in network environments with SERCOS III, Modbus TCP, EtherNet / IP and POWERLINK. A lively debate quickly developed around this technology demonstration itself and the importance of disclosing the system under an open source license. Some violent statements for and against openSAFETY appeared in the German trade press on the occasion of the trade fair and in further reporting.

The openSAFETY presentation in Hanover was followed by a series of information events on this technology at smaller specialist events, such as a lecture at the 9th International Symposium of TÜV Rheinland in May 2010 in Cologne. At this conference on functional safety in industrial applications, Stefan Schönegger from the Austrian company B&R Industrial Automation GmbH (B&R), which is a co-developer and key sponsor of openSAFETY, presented an overview of the main properties and functions of the protocol. Further events at later industry forums were increasingly devoted to the way in which the protocol was set up and specific application questions, following presentations in the specialist press.

Web links

References and comments

↑ The standard IEC 61784-3 deals with industrial communication networks - Profiles - Part 3: Fieldbuses for functional safety .
↑ "OpenSAFETY - Worldwide standard confirmed by IEC." electrical engineering , issue 7 + 8/2011, p. 32.
↑ Lydon, Bill. "Multivendor Ethernet Safety Protocol - Noble Goal." Website of the specialist medium automation . April 2011. This article deals with the most important aspects of the functional spectrum of technology. Lydon finds that “concept could be simply an interesting idea but the openSAFETY group has published a number of testimonials from users”. He then named executives from large companies such as Alstom Power Automation & Controls and Nestlé Corporate Engineering, who have thus openly supported openSAFETY.
↑ Details on the standard Ethernet frame format and the principle of encapsulation can be found in Chapter 3.Media Access Control (MAC) frame and packet specifications of the Ethernet standard IEEE 802.3-2008, Section 1 (Section One) ( page no longer available , Search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. .@1@ 2

↑ Detailed information about the features and functions of the protocol, which supplement and expand the brief description here, can be found on the official openSAFETY website (for URL, see section Weblinks below). Stefan Schönegger, one of the co-developers of the technology, also provided a clear presentation of the functional principles and security mechanisms. a. in the guest article “Bus-independent safety with openSafety” for the SPS magazine , issue HMI-Special 2011, April 2011, pp. 156–158.

↑ "EPSG: openSafety solution - now also available for Profinet." elektro AUTOMATION , issue 1 + 2/2011, p. 18. The short press release explains that the use of openSAFETY in connection with PROFINET systems had recently become possible, and that this option for long-term compatibility with bus systems such as SERCOS III , Modbus TCP, EtherNet / IP and POWERLINK was added.

↑ "Three Variants Dominate Industrial Ethernet." ControlDesign.com website . April 29, 2010. The article refers to a study by IMS Research, which calculated a combined market share of 91% for EtherNet / IP, PROFInet, Modbus TCP and POWERLINK.

↑ Verhappen, Ian. "The Hidden Network." ControlGlobal.com website . April 2, 2011. Verhappen notes the increasing use of the term in technical terms, problematizes the error in a precise definition for it and goes into more detail on the concrete implementation of the black channel transmission of safety data.

↑ Some of the specifications of other safety protocols were presented much earlier, in the case of PROFIsafe, for example, as early as 1999.

↑ Presher, Al. "New openSAFETY Protocol." ( Memento of the original from April 24, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Website DesignNews . July 10, 2010.

↑ Articles with critical appraisals of the technology or disputes about it appeared, for example, in open automation (“A safety standard in discussion”, issue 3/2010, pp. 54–55), Computer & Automation (“Interview - Ein Safety-Standard für alle? ”, issue 5/2010, pp. 18–20), messtec drives Automation (“ Knalleffekt - OpenSafety für Alle? ”, issue 6/2010, pp. 36–37) and A&D (“ In the ring - two opinions on OpenSafety ”, edition 9/2010, p. 65). In these publications, interviewees in particular who acted as representatives of associations or as important supporters behind other, proprietary security solutions such as B. CIP Safety stand for SERCOS III.

↑ Schönegger, Stefan. "OpenSAFETY - The standard for safe communication." ( Memento of the original from July 17, 2011 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.

^ "First Korea Industrial Ethernet Conference." In the news section of the website of the Industrial Ethernet Book it is reported that 140 participants at this conference attended events on “various aspects of the implementation of POWERLINK and openSAFETY”, and that “reference projects as well as hardware components” were presented at these events.

↑ "Second Industrial Ethernet Conference in Paris." Process Engineering Control & Maintenance , April 2011 edition, p. 32. This article explains that “participants from more than 50 companies” attended the event on which “topics such as openSAFETY and the implementation of applications with the first open, bus -independent safety protocol worldwide ”were covered by a number of speakers.

[1] The standard IEC 61784-3 deals with industrial communication networks - Profiles - Part 3: Fieldbuses for functional safety .

[2] "OpenSAFETY - Worldwide standard confirmed by IEC." electrical engineering , issue 7 + 8/2011, p. 32.

[3] Lydon, Bill. "Multivendor Ethernet Safety Protocol - Noble Goal." Website of the specialist medium automation . April 2011. This article deals with the most important aspects of the functional spectrum of technology. Lydon finds that “concept could be simply an interesting idea but the openSAFETY group has published a number of testimonials from users”. He then named executives from large companies such as Alstom Power Automation & Controls and Nestlé Corporate Engineering, who have thus openly supported openSAFETY.

[4] Details on the standard Ethernet frame format and the principle of encapsulation can be found in Chapter 3.Media Access Control (MAC) frame and packet specifications of the Ethernet standard IEEE 802.3-2008, Section 1 (Section One) ( page no longer available , Search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. .@1@ 2

[5] Detailed information about the features and functions of the protocol, which supplement and expand the brief description here, can be found on the official openSAFETY website (for URL, see section Weblinks below). Stefan Schönegger, one of the co-developers of the technology, also provided a clear presentation of the functional principles and security mechanisms. a. in the guest article “Bus-independent safety with openSafety” for the SPS magazine , issue HMI-Special 2011, April 2011, pp. 156–158.

[6] "EPSG: openSafety solution - now also available for Profinet." elektro AUTOMATION , issue 1 + 2/2011, p. 18. The short press release explains that the use of openSAFETY in connection with PROFINET systems had recently become possible, and that this option for long-term compatibility with bus systems such as SERCOS III , Modbus TCP, EtherNet / IP and POWERLINK was added.

[7] "Three Variants Dominate Industrial Ethernet." ControlDesign.com website . April 29, 2010. The article refers to a study by IMS Research, which calculated a combined market share of 91% for EtherNet / IP, PROFInet, Modbus TCP and POWERLINK.

[8] Verhappen, Ian. "The Hidden Network." ControlGlobal.com website . April 2, 2011. Verhappen notes the increasing use of the term in technical terms, problematizes the error in a precise definition for it and goes into more detail on the concrete implementation of the black channel transmission of safety data.

[9] Some of the specifications of other safety protocols were presented much earlier, in the case of PROFIsafe, for example, as early as 1999.

[10] Presher, Al. "New openSAFETY Protocol." ( Memento of the original from April 24, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Website DesignNews . July 10, 2010. @1@ 2

[11] Articles with critical appraisals of the technology or disputes about it appeared, for example, in open automation (“A safety standard in discussion”, issue 3/2010, pp. 54–55), Computer & Automation (“Interview - Ein Safety-Standard für alle? ”, issue 5/2010, pp. 18–20), messtec drives Automation (“ Knalleffekt - OpenSafety für Alle? ”, issue 6/2010, pp. 36–37) and A&D (“ In the ring - two opinions on OpenSafety ”, edition 9/2010, p. 65). In these publications, interviewees in particular who acted as representatives of associations or as important supporters behind other, proprietary security solutions such as B. CIP Safety stand for SERCOS III.

[12] Schönegger, Stefan. "OpenSAFETY - The standard for safe communication." ( Memento of the original from July 17, 2011 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2

[13] "First Korea Industrial Ethernet Conference." In the news section of the website of the Industrial Ethernet Book it is reported that 140 participants at this conference attended events on “various aspects of the implementation of POWERLINK and openSAFETY”, and that “reference projects as well as hardware components” were presented at these events.

[14] "Second Industrial Ethernet Conference in Paris." Process Engineering Control & Maintenance , April 2011 edition, p. 32. This article explains that “participants from more than 50 companies” attended the event on which “topics such as openSAFETY and the implementation of applications with the first open, bus -independent safety protocol worldwide ”were covered by a number of speakers.