Patent ID: 7730240

Claim:
A monitoring/control system for defining a cycle time for a transmission cycle on a system bus, comprising: at least one communication module and connected to the system bus; and at least one signal input/output module connected to the communication module via the system bus, wherein the at least one communication module has a time control unit for controlling a transmission cycle which is constantly repeatedly carried out by the communication module and the signal input/output modules, the transmission cycle comprising defined communication times for the communication module and the signal input/output modules to communicate signals through the system bus, wherein the time control unit is arranged to measure signal propagation times on the system bus and to define the cycle time for a transmission cycle on the system bus on the basis of the longest signal propagation time measured, and to transmit the defined cycle time to all of the signal input/output modules, wherein the measuring and defining includes a) measuring the signal propagation times on the system bus and, based on the measuring, determining the longest signal propagation time, b) determining the maximum signal transfer rate, based on said determined longest signal propagation time, c) determining the minimum cycle time of a transmission cycle based on said determined maximum signal transfer rate, and d) transmitting the minimum cycle time to all of the communication and signal input/output modules connected to the system bus, to control the access times to the system bus.