| 摘要 |
Operating a field bus network system (N) with ring topology which comprises a master unit (ECU) and a multiplicity of slave units (SE10, SE20, SE30, SE40), which are connected by a field bus (B) in ring topology. A data message (DB), which comprises a first counter device (CTO) and a second counter device (CPAS), is sent from the master unit (ECU) to a slave unit (SE10, SE20, SE30, SE40). A counter state of the first counter device (CTO) is used to display a required number of forwarding steps via intermediate slave units (SE10, SE20, SE30, SE40) in the ring topology as far as the slave unit (SE10, SE20, SE30, SE40) intended to receive the data message (DB) and a counter state of the second counter device (CPAS) is used to display a completed number of forwarding steps via intermediate slave units (SE10, SE20, SE30, SE40) in the ring topology. The slave units (SE10, SE20, SE30, SE40) modify the counter state of the first counter device (CTO) with a first predetermined algorithm upon receiving the data message (DB) and determine with the aid of the modified counter state of the first counter device (CTO) whether they are the slave unit (SE10, SE20, SE30, SE40) intended to receive the data message (DB). The slave units (SE10, SE20, SE30, SE40) also modify the counter state of the second counter device (CPAS) with a second predetermined algorithm upon receiving the data message (DB). |
