Abstract: A method for modifying one or more parameters for the operation of a network, especially based on the PROFIBUS specification. In particular, a method for enabling an automatic reparameterization of all of the users in the network. A central user (1) sends a request message (T1) for parameter modification to the other users (2 . . . 5) in the network. The users (1 . . . 5) then go into an offline state for a predeterminable minimum duration and revert back to the online state with the new operating parameterization The respective minimum duration of the offline state is preset such that users with different operating parameterizations are at no time simultaneously in the online state. Further measures can render the method fault-tolerant.

Abstract: A user terminal (1) having a communications processor (10) that carries out a cyclic data transmission. During a cyclic part (ZYK,x) of a cycle (Z,x) in which user data are transmitted, a DP application may not access the memory (14, 15). In the communications processor (10), the memory (14, 15) stores a process image. The communications processor (10), for the purpose of synchronization, transmits at the beginning of a cycle a cycle start interrupt (ZSI,x) and at the end of the cyclic part (ZYK,x) a cycle end interrupt (ZEI,x). Once the arithmetic unit (5, 7, 8) has accessed the memory it releases the interrupts. The duration (&Dgr;T′s2,1; &Dgr;T′e2,1) between two successive interrupts serves to detect access violations and to initiate appropriate fault treatment measures.

Abstract: A user terminal (1) having a communications processor (10) that carries out a cyclic data transmission. During a cyclic part (ZYK,x) of a cycle (Z,x) in which user data are transmitted, a DP application may not access the memory (14, 15). In the communications processor (10), the memory (14, 15) stores a process image. The communications processor (10), for the purpose of synchronization, transmits at the beginning of a cycle a cycle start interrupt (ZSI,x) and at the end of the cyclic part (ZYK,x) a cycle end interrupt (ZEI,x). Once the arithmetic unit (5, 7, 8) has accessed the memory it releases the interrupts. The duration (&Dgr;T′s2,1; &Dgr;T′e2,1) between two successive interrupts serves to detect access violations and to initiate appropriate fault treatment measures.