Fault tolerance in Interbus-S standard

The paper deals with the fault tolerance in the Interbus-S, one of the most used FieldBus communication systems. Industrial environments are often featured by critical processes to be controlled. For this reason, the use of a FieldBus to convey information on which these processes are based, requires the presence of fault tolerance mechanisms able to recover a fault in the communication system on its occurrence. In the paper, the authors will highlight the vulnerability of the Interbus-S to fault occurrence in a particular communication node, the Master, foreseen by the Interbus-S standard to distribute the available bandwidth to the control devices connected to the communication system. Finally, the authors will present a protocol extension that allows the whole communication system to continue working after the occurrence of a fault in the Master. The main feature of the proposal is its full compatibility with the Interbus-S standard, as it will be shown in the paper. (C) 2001 Elsevier Science B.V. All rights reserved.