Hard real-time communication with RTFL

The RTFL transport layer of SafetyNET p is optimized for the fastest real-time applications. Typically the devices are networked in a linear structure, as with traditional fieldbus systems. All the bus subscribers have equal rights. Data is exchanged in accordance with the publisher/subscriber principle. As a publisher, each device can provide data to the other devices (subscribers) via SafetyNET p. In turn these subscribers can read
the published data from individual subscribers or all subscribers. This way it is possible to exchange data efficiently between all the subscribers. The communication mechanism used by RTFL is a very fast cyclical data transfer in one single Ethernet data frame or multiple data frames per cycle. Communication is initiated by a  special device called the Root Device (RD). The Ethernet frame generated within the Root Device is then  transferred to the other devices (OD – Ordinary Device). The ODs fill the Ethernet frame with data to be  published and extract from the Ethernet frame the data to be read. The devices are addressed via their MAC address. Each RTFL network requires just one Root Device. Each RTFL device has two Ethernet interfaces, which enables the familiar daisy chain wiring often found on fieldbuses.