Periodic messages and function blocks scheduling in FF system

This paper presents remote periodic messages and function blocks (FBs) scheduling in a single segment Foundation fieldbus (FF) system. First, we regard remote periodic messages and FBs as tasks, and then propose a compact mode and only consider precedence constraints to build the model of tasks, in which each job is completed as earlier as possible. Next, considering the communication block, a scheduling algorithm based on job slack time monotonic and compact mode for all remote periodic messages and FBs is presented in order to meet their precedence constraints and time constraints. Finally, an example of application shows the process of scheduling of remote periodic messages and FBs.