Procedure for communication over a bus between a process data server and at least one receiver

摘要

The data server (1) and at least one receiver (2) connected to a bus (3) which is also connected to a master clock (4) which periodically sends time information (5) to the data server (1) and the receiver (2). The data server (1) sends a telegram (6) to the receiver (2) which includes a process data server time (7) and the receiver forms a time difference from the time information and the process data server time and triggers a safety reaction when the difference exceeds a specified threshold value. The data server (1) sends a test telegram (8) at least one specifiable time to the master clock (4) and the latter sends an acknowledgement telegram (9) to the data server (1), for the latter to ascertain a telegram transit time and to release a safety reaction if the telegram transit time exceeds a given threshold value.