SafetyBUS p

SafetyBUS p is a standard for fail-safe fieldbus communication in automation technology.

It meets SIL 3 of IEC 61508 as well as the safety category Category 4 of EN 954-1, respectively Performance Level "e " of the successor standard to EN 13849-1.


SafetyBUS p KG was developed in the years 1995 to 1999 by Pilz GmbH & Co.. The aim was to provide a fieldbus for communication of data in the sense of machine safety.

The technology of SafetyBUS p by the user group Safety Network International eV (formerly SafetyBUS p Club International eV ) is managed since 1999, in which the members are working on the development of the SafetyBUS p.


The main use of SafetyBUS p is the communication of data with security sensitive content. SafetyBUS 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.

Typical applications are:

  • Factory automation (eg, automobile manufacturing, pressing)
  • Transportation technology (eg, cable cars, rides )

SafetyBUS p can be used for applications with technical safety requirements up to SIL 3 of IEC 61508 or Category 4 of EN 954-1.


SafetyBUS p technologically based on the fieldbus system CAN. In addition to the already defined in CAN OSI layers 1 and 2 for the Physical Layer and fuse added p additional mechanisms to secure the transmission in layers 2 and 7 at SafetyBUS.

Failure mechanisms

For the detection of transmission errors and equipment come with SafetyBUS p, the following mechanisms are used:

  • Serial numbers
  • Time expectancy
  • Echo
  • Identifier for the sender and receiver
  • Data backup (CRC)


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

  • Up to 64 bus nodes per network
  • Up to 4000 I / O points per network
  • Transmission rates from 20 to 500 kbps, depending on network expansion
  • Individual network segments can have up to 3500 m expansion.
  • Several network segments can be coupled
  • Guaranteed error reaction times up to 20 ms are possible
  • Suitable for applications according to SIL 3 of IEC 61508 and Category 4 of EN 954-1
  • Optional power supply of the devices on the LAN cable
  • Subnets can be realized in wireless technology, with fiber-optic cables as well as an infrared connection.


In SafetyBUS p networks only safety devices are used. These are built internally in the multi-channel rule. The safety use of the equipment normally requires a certification of safety by authorized testing laboratories. This inspect the equipment according to the applicable standards and regulations. A functional test is performed by the user group Safety Network International eV.


Since 1999, the user group Safety Bus p Club International eV exists in which manufacturers and users have come together SafetyBUS p. 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, the organization developed the system further so SafetyNET p could be provided as a successor..