Experimental evaluation of a bandwidth allocation scheme for foundation fieldbus

Operation of the data link layer of the foundation fieldbus is based on scheduling and token-passing disciplines. This paper presents a network design for the foundation fieldbus protocol using a bandwidth allocation scheme. Fieldbus traffic consists of periodic data and sporadically generated time-critical and time-available data. The bandwidth allocation scheme schedules the transmission of periodic data. Time-critical and time-available data are transmitted via a token-passing service. The validity of this bandwidth allocation scheme was determined using an experimental model of a network system. The results obtained from the model show that the proposed scheme restricted the delay of both periodic and time-critical data to a pre-specified bound. The proposed bandwidth allocation scheme also fully utilized the bandwidth resources of the network system.