SafetyNET p

SafetyNET p is a standard for Ethernet-based fieldbus communication in automation technology. Due to the real-time behavior with cycle times to 62.5 microseconds SafetyNET p is suitable as a drive. It can be used in accordance with the standard requirements of EN 61508 and EN 61511 in safety circuits up to and including the category SIL 3.


SafetyNET p is a registered trademark of Pilz GmbH & Co. KG and was introduced to the public in 2006 for the first time. The aim was to enable the fieldbus communication on Ethernet in real time and at the same time provide for the communication of data in the sense of machine safety. SafetyNET p united Safety and Automation: it is both a safety and an automation fieldbus and thus the successor of SafetyBUS p.

The technology of SafetyNET p is administered by the umbrella organization Safety Network International eV.


In addition to use as an Ethernet-based fieldbus is a priority of use of SafetyNET p in the communication of data with safe content. SafetyNET p is thereby suited for applications where the timing and content consistency of data communicated to hedge risks is required. It may be at the dangers to the risk of life and limb, but also to the protection of assets.

A second application is the communication of data in real time. With bus cycle times of up to 62.5 microseconds can SafetyNET p itself be used in extremely time- critical areas.

Typical applications are:

  • Factory automation (eg, automobile manufacturing, pressing)
  • Transportation technology (eg, cable cars, rides )
  • Drive technology (for example, sensor-actuator control loop drives or industrial robots)

In general, all applications of automation and process are possible.


SafetyNET p is based on Ethernet. Here are two different, mutually compatible forms for SafetyNET p.


RTFN (real time frame network) uses for communication standard Ethernet IP frames. The mechanisms for security and real-time are based on the 3 and higher OSI layers. As a communication principle, a producer-consumer model will be used. A central process controller (PLC) is not required. This allows, among other concepts such as modular engineering.

SafetyNET p RTFN is fully compatible with all IP-based Ethernet protocols, and can be mixed with those on the same medium. Even conventional switches, routers and wireless access points can be used.

Due to possible competing services a system cycle time of about 1 ms can be achieved. If a higher performance is required so SafetyNET p RTFL can be used.


RTFL (real time frame line ) uses for communication Ethernet MAC frames. Even with RTFL a producer-consumer model is used at the logical level. To achieve the required performance, the communication is optimized instead of Ethernet MAC frames. For this purpose, an Ethernet MAC frame is sent to its logical neighbors from the first subscriber to the logical line. This filled his part of the frame and the frame extends along the logical line on each of its nearest neighbors. Thus, all participants filled in succession the frame. The last station of the line sends the filled frame on the same path ( by all participants) back to the first party. The individual participants can see the data they need in the passage of the frame.

The achievable system cycle times are in the range of 62.5 microseconds. Other, IP - based traffic, can be packaged by the SafetyNET p participants as part of the real-time communication within a RTFL frames.


The technology defined by the frame data of the SafetyNET p are as follows:

  • Compatible with Ethernet IP protocols
  • Networks can be established in line, star or tree topology
  • Networks with changing participants are possible by continuous topology scan
  • The maximum distance between two participants corresponds to that of conventional Ethernet ( when using copper lines, these are 100 m)
  • In RTFN the number of bus devices is limited only by the IP address space
  • In RTFL 512 bus devices per segment are possible
  • Guaranteed system cycle times up to 62.5 microseconds can be achieved
  • Suitable for applications according to SIL 3 of IEC 61508

In the " list of assigned port numbers " IANA registered port number is 40000 for SafetyNET p.


Since 1999, the user group Safety Bus p Club International eV exists in which manufacturers and users have come together from SafetyBUSp. The organization was renamed Safety Network International eV in 2006. In addition to the international organization, there are two other regional organizations: Japan, founded in 2000, and the United States, founded in 2001.