Method for operating a field bus network system having a ring topology and a corresponding field bus network system

摘要

A method is provided for operating a field bus network system having a ring topology, which has a master unit and a plurality of slave units, which are connected by a field bus in a ring topology. The method includes transmission of a data message by the master unit to a slave unit intended for receiving the data message, which has a first counter device and a second counter device, a count of the first counter device being used to display a number of required relay steps via interposed slave units in the ring topology up to the slave unit intended for receiving the data message and a count of the second counter device being used to display a number of completed relay steps via interposed slave units in the ring topology; the slave units modifying the count of the first counter device using a first predefined algorithm upon receipt of the data message and ascertaining on the basis of the modified count of the first counter device whether it is the slave unit intended to receive the data message; and the slave units modifying the count of the second counter device using a second predefined algorithm upon receipt of the data message.