PROFIsafe: Safe Communication


Safety-related and standard data is transferred using PROFIsafe via the same bus line. The black channel indicates that safety-related communication is independent of the bus system and the underlying network components.

PROFIsafe was the first communications standard conforming to the safety standard IEC 61508 that permits both standard and safety-related communications on one bus line. This not only results in an enormous savings potential with regard to cabling and the required number of parts, but also the advantage of retrofitting.

PROFIsafe is one of the open solutions for safety-related communication over standard field buses, and is defined in IEC 61784-3-3 as an international standard. Numerous manufacturers of safety components and end users of safety technology have helped develop this vendor-independent and open standard for PROFIBUS International (PI).

PROFIsafe profile allow safe communication for the open standard buses PROFIBUS and PROFINET on the basis of standard network components. In connection with PROFINET, PROFIsafe also supports failsafe wireless communication via IWLAN.

The table below shows how PROFIsafe deals with the various potential sources of errors when transmitting messages.

PROFIsafe – Measures against transmission errors



Consecutive number

Time expectation with acknowl-

Identification for transmitter and receiver

Data security CRC




Incorrect sequence

Data corruption


Coupling of safety-related messages and standard messages (masquerade)

FIFO errors (First In First Out data register for maintaining the sequence)