We received this press release from B&R Automation today. It appears that there's one more vote for doing everything via Ethernet...
The first open safety protocol for real-time Ethernet
Today, many safety solutions are based on hardware components that must be wired separately from the control network. The consequences are cost-intensive cabling and very limited diagnostics options. Another solution implements a safety controller that receives all signals directly or via a proprietary safe bus. With these types of systems, special cables and specific safe bus components are needed, which brings about additional costs.
A third, very innovative option developed by B&R provides the solution: B&R's ETHERNET Powerlink Safety Technology. All safety-oriented mechanisms, which are open and available, are implemented in the data transfer process so that safety-relevant data can be transferred over a standard fieldbus. With this solution, safety functionality is completely integrated in the control system and does not require special cabling. This results in a considerable cost advantage. All relevant standards for safe data transfer, as required by the automation industry, are achieved according to IEC 61508 SIL Cat3.
EPL Safety Technology is independent of the transport protocol, i.e. it is completely compatible with other fieldbus solutions such as CANopen. Thanks to its performance and flexibility, Powerlink provides many advantages: It reduces wiring, prevents errors and provides real-time capability and 10x shorter reaction times.
