Introduction of PROFIsafe into plant automation means a threefold quantum leap:
Internationally established technology
PROFIsafe is an integrated safety technology for discrete manufacturing and process automation. The IEC 61508-compliant technology enjoys widespread international acceptance and has been evaluated positively by IFA and TÜV. PROFIsafe has also become an international standard (IEC 61784-3-3).
Efficient use of technology and product
The wide range of products from different manufacturers enables easy, cost-effective system configuration. Training, documentation, and maintenance are required for only a single bus technology, thus saving time and money for system operation.
Simple engineering and installation
Standard and safety-related applications can be programmed for PROFIsafe by means of a single tool and certified function blocks. In addition, the technology enables a high degree of flexibility when replacing existing relay technology and when retrofitting existing installations. The use of certified devices simplifies system acceptance.
Same cost savings as with the introduction of standard PROFI-BUS: reduced wiring, flexible configurations, parameterization, and diagnosis. Easy and cost-efficient system design with a broad product spectrum from all types of manufacturers. Cost saving system acceptance due to certified devices.
Easy implementation of a PROFIsafe solution
A PROFIsafe solution can be easily implemented and inexpensively replicated using TÜV-certified software.
Flexibility based on different architectures
The different architectures of safety-relevant control systems can adapt PROFIsafe communication without difficulty. PROFIsafe thus opens the door to new and innovative device functions.
PROFIsafe is an established technology with significant future potential. PROFIBUS &
PROFINET International (PI) functions as a global network of experts who work cooperatively on further technology development. Investments are protected as a result of this longterm development strategy. All existing and future PROFIBUS standards are used, and will continue to be used, for safety-relevant applications, as well. A simple migration to PROFINET is possible based on the black channel principle (PROFIBUS DP/PROFINET IO).
The PROFIsafe protocol is suitable for both PROFIBUS and PROFINET networks without impacts on these existing fieldbus standards. It is possible to transmit safety messages on the existing standard bus cables in coexistence with the standard messages. Conventional and F-instrumentation can be operated on one single bus cable including the use of standard PLCs with integrated but logically separated safety processing.
Fig. 1: The single-channel approach
The PROFIsafe protocol has not any impact on the standard bus protocols. It is as independent as possible from the base transmission channels be it copper wires, fiber optics, wireless, or backplanes. Neither the transmission rates nor the error detection mechanisms play a role. For PROFIsafe they are just "Black Channels" (Figure 2). Thus, the PROFIsafe protocol overtakes, for the users, the safety assessment of their individual backplane communication and also transmission paths beyond the PROFINET and PROFIBUS networks. It secures the whole path from the location where a safety signal originates to the location where it is processed and vice versa.
The PROFIsafe protocol can be used for safety applications up to SIL3 according to
IEC 61508 / IEC 62061, or Category 4 according to EN 954-1, or PL "e" according to
Fig. 2: The "Black Channel" approach
It is the task of safety communication between two partners to deliver correct data to the right destination just-in-time. Various transmission errors may occur when messages are transferred in complex network topologies, whether due to hardware failures, extraordinary electromagnetic interference, or other influences.
Out of the numerous remedies known from literature, PROFIsafe concentrates on those presented in the matrix shown in Figure 3.
Fig. 3: Transmission error types and safety remedies
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