Posted by: Harold Ennulat | June 1, 2011


PROFIsafe has become an international standard (IEC 61784-3-3).  PROFIsafe is a safety protocol that can coexist on any network.


What is PROFIsafe:  From Wikipedia:

PROFIsafe (PROFIBUS safety or PROFINET safety) is the first open functional safety communication technology for distributed automation systems worldwide. Its specification for PROFIBUS DP and PROFIBUS PA was published first back in spring 1999. It incorporates the knowledge of more than 25 renowned safety companies. Extensions for the Ethernet based PROFINET IO followed in fall 2005. More than 100,000 automation systems with more than 1 Million PROFIsafe nodes are currently in use worldwide (spring 2011).

In the past, safety automation had to be “hard-wired” and based on “relay” technology due to existing international standards. This changed with the advent of a new standard – IEC 61508 – specifying how microcontrollers and software can be used in safety automation. This triggered the development of PROFIsafe, which was to integrate safety into the existing standard PROFIBUS fieldbus technologies. PROFIsafe is designed as a separate layer on top of the fieldbus application layer and reduces the error probability of the data transmission to the level required by or better than the relevant standards. PROFIsafe messages are using the existing standard fieldbus cables in coexistence with the standard messages (“Single Channel”). PROFIsafe does not benefit from any error detection mechanisms of underlying transmission channels and thus supports the securing of whole communication paths, even backplanes inside controllers or remote I/O. PROFIsafe coined the term “Black Channel” for this concept, which now is adopted by most of the other safety fieldbusses. PROFIsafe can be used in safety applications up to Safety Integrity Level 3 (SIL) according to IEC 61508, Performance Level “e” (PL) according to ISO 13849, or Category 4 according to EN 954-1.

PROFIsafe is using expanded fault (errors and failures) detection mechanisms such as

  • Consecutive numbering
  • Timeout monitoring
  • Source/destination authentication
  • Cyclic redundancy checking (CRC)

PROFIsafe is standardized in IEC 61784-3-3. It also is a Chinese standard (GB/Z 20830-2007).

PROFIsafe runs its own web portal on (see Web Links) with more details on the technology and hints for device developers, integrators and end users.

The PROFIsafe standard is maintained, updated and marketed by PROFIBUS International, a non-profit organisation administered from Karlsruhe in Germany. PROFIBUS International is also responsible for the development of PROFIBUS and PROFINET, an Ethernet based fieldnetwork.


Here are some quick links:

For a good general overview:

From Profibus International (PI):  Be sure to checkout the related links in the left side bar.

Vendors supporting it include:


Phoenix Contact:


My thanks to Chad Tverberg at Control Assemblies for making me aware of this.




For another openSAFETY standard protocol that can coexist on other networks including ProfiNet or ProfiBus apparently see:


Updated: June 2, 2011  8:55pm  |  Created May 31, 2011



  1. Additional resources for PROFIsafe:

    The PROFIblog with tag “PROFIsafe” ( has news, pictures, and videos of PROFIsafe.

    There is also a PROFIsafe webinar describing the technology at

    –Carl Henning

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