ABSTRACT
It is an open architecture, serial bus, master-slave type fieldbus communication system that operates in active ring topology. The protocol is deterministic, cyclic, and full duplex in nature and is manufacturer independent. It can handle both process and parameter data. Process data is transmitted in real-time cyclically while parameter data is transferred in an acyclic way. It consists of one master and up to 511 slave devices. The data transfer rate on the bus is 500 kbps.
An Interbus-S system comprises the communication bus master, bus coupler, and devices (slaves). These are connected by local as well as remote buses.
A bus cycle begins with the master passing a bit stream to the first slave. The first slave passes the same to the second slave in the ring and at the same time data from the first slave is transferred to the master.
The protocol structure follows the open systems interconnection (OSI) reference model, but contains only layers 1, 2, and 7. The application layer accesses data from the slaves, the physical layer determines the baud rate and data encoding and the data link layer ensures data integrity.
