A method for operating via a data bus by means of serial data exchange, which communicate with one another computer units

摘要

A process is disclosed for operating computing units in communication with each other by serial data transfer over a data bus. Each computing unit has its own clock generating system and the computing units exchange timing information over the data bus. In order to generate a common time base using the transfer protocol valid for the system, a time recording start signal is at first supplied to the data bus; then each computing unit stores its own time value when it identifies the time recording start signal, transfers the stored own time value at a later moment in time to the other computing units and stores the time values received from the other computing units. Each computing unit then compares its own stored time value to the stored time values of the other computing units and calculates the present time value of the other computing units taking into account its own present time value. Each computing node can thus very accurately ascertain the relation between its local time and the local time base of the other computing units or of a reference node, without having to adjust or correct the local time base.