PROFIsafe Key Frequently Asked Questions

Safety systems protect equipment, people, and the environment. Traditionally, safety systems rely on separately wired circuits that are expensive to build, commission, and maintain. Nowadays, functional safety can be done over the bus shifting from safety in hard relays to safety in logic. With over 11 million installed nodes worldwide, PROFIsafe is the industry-leading solution for functional safety over the bus. PROFIsafe ensures the integrity of failsafe signals transmitted between safety devices and a safety controller meeting the relevant safety standards. Specifically, such standards include the highest safety categories: up to SIL3 according to IEC 61508 / IEC 62061, and Category 4 according to EN 954-1, or PL “e” according to ISO 13849-1. The following section answers frequently asked questions about PROFIsafe.


Are PROFIsafe devices PROFINET devices?

Yes, PROFIsafe is an application profile of PROFINET. They are PROFINET devices with PROFIsafe capabilities. Therefore, they must be engineered following the PROFINET standard. Then, device manufacturers add a software layer to provide functional safety. The following diagram illustrates the concept.

PROFIsafe plays a role in the Common Application Profiles layer.

Do all PROFINET devices have PROFIsafe capabilities?

No, not all PROFINET devices have PROFIsafe capabilities. But, this is not a hurdle. In fact, there are hundreds of PROFINET products that offer PROFIsafe capabilities. You can search for products online or ask your preferred vendor for PROFIsafe capable controllers and devices.

Can you send PROFIsafe messages over wireless?

Yes, PROFIsafe is safety certified over wireless media using PROFINET.

What communication channel do safety messages use? Real-Time or Isochronous Real-Time(IRT)?

The end-user decides which is the most suitable communication channel for each particular application. The decision is usually based on several factors, including cycle time and determinism requirements. Generally, the real-time channel will deliver the necessary performance for most applications(including safety). Yet, some applications, such as motion control, might have higher requirements. Then, the user can opt for the IRT communication channel. This channel delivers messages with cycle times down to 31.25 us with 1 us of jitter. It is worth mentioning that users that plan on using the IRT communication channel would need to get the appropriate hardware.

Are PROFIsafe products certified by PROFIBUS and PROFINET International(PI)?

Yes. Certification of the PROFIsafe application profile is mandatory. Device manufacturers must certify their product for this specific profile before it is available to the public(more on product certification).

Is PROFIsafe available for PROFIBUS?

Yes, it is an application profile for both PROFIBUS and PROFINET.

More Questions?

Feel free to reach out to us! (contact us). Also, learn more about functional safety for PROFIBUS and PROFINET with this informative webinar:

PROFIsafe – Functional Safety over PROFIBUS and PROFINET

-Nelly Ayllon