Architecture and model of Profinet IO

This work presents the communication architecture and model for Profinet IO that has been currently released by the Profibus User Organization. Profinet IO provides the service definition and protocol specification for real time communication based on Ethernet, IP, and UDP for the field bus domain. It defines services and protocols mainly for communication between IO controllers (e.g. a PLC) and IO devices (e.g. Remote IO). It Includes a QoS architecture for real time control and alarm messages taking precedence over parameter, diagnosis, or Infrastructure messages Including other TCP or UDP based protocols. High message priorities In combination with a time division multiplexing approach with direct data link layer access provide short cycle times and low jitter. The IO device model itself is an enhancement of the Profibus DP device model. The enhancement includes a more flexible control access of one or more IO controllers in parallel to one IO device. Furthermore, address parameters and levels are enhanced too. The specification itself is according to IEC 61158 styles, which opens the possibility to be easily added in a new maintenance period of the standard.