Industrial Ethernet communication system
SafetyNET p is defined in the IEC standards series for industrial fieldbus systems as Type 22 and CP 18 and has emerged as the standard for Ethernet-based fieldbus communication in automation technology.
SafetyNET p in automation
SafetyNET p enables automation data and safety-related data to be transmitted simultaneously, whereby horizontal and vertical integration of automation and functional safety are available in a single communication protocol.
SafetyNET p – Communication model
The SafetyNET p communication model describes the communication system and its two components, the application layer and the transport layer. The application layer transmits the existing device function from the application side into a generic functionality on the SafetyNET p side. As SafetyNET p uses two different transport mechanisms, i.e. RTFL and RTFN, there are two transport layer implementations. In its two guises RTFN and RTFL, SafetyNET p is at home on all levels of the automation pyramid: while SafetyNET p RTFN is used for communication within an automation cell or vertically with Office and ERP networks, SafetyNET p RTFL is preferred on applications with the highest reaction time requirements. The application layer of RTFL and RTFN devices is identical: The only difference is in the transport layer, which in the case of RTFL is implemented using an FPGA chip.
SafetyNET p uses the familiar CANopen device profiles. This allows manufacturers to build on familiar interfaces and reduce the work involved in interface implementation to a minimum.
The application layer represents the application’s interface to the communication system. All of a device’s SafetyNET p functions are made accessible via the application layer. The application layer represents the interface between the user and the communication system. SafetyNET p uses the popular CANopen application layer. As the CANopen device profiles are not committed to a specific communications medium, they can be used for SafetyNET p. From the perspective of today’s CANopen users, this means that they can fall back on familiar interfaces.
Implementation of SafetyNET p
Simple, flexible and economical implementation options are the key to gaining acceptance of an industrial communication system among manufacturers of automation devices. These requirements have been considered on SafetyNET p: various options are available for the implementation of SafetyNET p devices. The manufacturer can therefore reduce the effort required for interface implementation to a minimum. The application layer of RTFL and RTFN devices is identical. RTFL and RTFN implementations differ only in the transport layer, where RTFL uses an FPGA chip.