PROFINET and PROFIsafe have very similar names and were both created by PROFIBUS and PROFINET International (PI). Besides the similarities in origin and name, PROFINET and PROFIsafe are different technologies.
PROFINET is an open industrial Ethernet standard that offers real-time data exchange while maintaining openness for flexible plant and machine concepts. Aside from the standard characteristics in each PROFINET device, optional features, like, for example, PROFIsafe, provide additional functionality. PROFIsafe extends the standard PROFINET communication protocol to address unique requirements for functional safety-related information necessary to conform to strict safety standards.
The next section expands on the roles of PROFINET and PROFIsafe.
PROFINET vs PROFIsafe
PROFINET is an Industrial Ethernet solution. It is a communication protocol to exchange data between controllers and devices. Controllers can be PLCs, DCSs, or PACs. Devices can be I/O blocks, vision systems, RFID readers, drives, process instruments, proxies, or even other controllers. PROFINET is an application that defines cyclic and acyclic communication between components, including diagnostics and alarms.
PROFIsafe is an additional software layer that provides functional safety over the bus in PROFINET (or PROFIBUS) networks. PROFIsafe will take care of the functional safety portion of communications. It ensures the integrity of failsafe signals transmitted between safety devices and a safety controller meeting the relevant safety standards for industrial networks (up to SIL3 according to IEC 61508 / IEC 62061, or Category 4 according to EN 954-1, or PL “e” according to ISO 13849-1).
The diagram below illustrates the difference between PROFIsafe and PROFINET in terms of roles. PROFINET is the overall communication protocol. PROFIsafe is an additional layer that fulfills the functional safety requirements of the application.
PROFIsafe is an optional feature of PROFINET. Within the list of PROFINET’s optional features, PROFIsafe is part of the Application Profile subgroup. Application Profiles are developed in PI working groups to ensure the openness, interoperability, and interchangeability of devices. PROFINET Application Profiles are vendor-independent specifications. They are implemented into PROFINET devices to enable the uniform behavior of devices from different manufacturers.
Since PROFIsafe is an optional feature, not all PROFINET devices support PROFIsafe. The user must select the appropriate safety components to implement PROFIsafe. During implementation, the user must select network components that require safety; only those network components require PROFIsafe capabilities.
The overall network configuration may contain a mix of fail-safe and standard components. The diagram below shows an example of a PROFINET network with a mix of PROFINET components; some have PROFIsafe capabilities (yellow); others do not (gray). Also, PROFIsafe is designed to work independently of the base transmission channel, whether that channel is copper wire, fiber optics, wireless, or a backplane.
Can you add PROFIsafe to existing PROFINET devices?
It depends on the device and device manufacturer. First, there should be a version of the current device that supports PROFIsafe. If that version is available, the device manufacturer may offer the option to add the PROFIsafe capability with a firmware/software update.
Are PROFIsafe devices PROFINET devices?
Yes. Since PROFIsafe is an application profile of PROFINET, they are PROFINET devices with PROFIsafe capabilities. Those components must be engineered following the PROFINET standard. The device manufacturers also add a software layer to implement functional safety (PROFIsafe).
Do all PROFINET devices have PROFIsafe capabilities?
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.
Additional PROFIsafe Resources
- PROFIsafe Webinar: https://us.profinet.com/webinar/profisafe-functional-safety-over-profibus-and-profinet/
- Application Profile White Paper (with PROFIsafe section): https://us.profinet.com/white-papers/profinet-application-profiles-profisafe-profienergy-profidrive/
- PROFIsafe Marketing Overview: https://us.profinet.com/documentation/marketing-flyer-profisafe/