AVAILABILITY THROUGH FIELD DEVICE DIAGNOSIS IN FEEDFORWARD CONTROL: A CASE STUDY OF FOUNDATION FIELDBUS-BASED TEMPERATURE CONTROL

For endusers, requiring an action to enable a fieldbus-based process control that is not hazardous to continue its operation in the event of transmitter failures, it is essential to understand how diagnostic capability of field instruments is helpful in availability enhancement. In order to effectively implement a feedforward control strategy with increased availability, this article presents a control configuration method when utilizing a Foundation Fieldbus (FF)-based temperature feedforward control as an illustrative case study. Four function block assignment options for configuring the studied control strategy during engineering phase are described. The ‘Uncertain’ measurement status provided by temperature transmitters is treated as ‘Good’ measurement status in all control configuration options for availability goal by reducing process downtime. In addition, based on experimental results, a simplified Petri net model for logical behavior representation of the interested FF-based feedforward is also proposed.