COMPARATIVE ANALYSIS BETWEEN CONTROL IN THE HOST AND CONTROL IN THE FIELD IN TERMS OF SAFETY AND AVAILABILITY FOR FOUNDATION FIELDBUS-BASED PROCESS CONTROL

摘要

Design work of process control to provide necessary performance requirements must be based on capabilities and limitations of the technology used. This paper aims at analyzing possible safety and availability enhancements of basic process control based on Foundation Fieldbus (FF) technology in which the control function blocks can be assigned either in the host system controller，called 'Control in the Host' (CIH)，or in the field devices, called 'Control in the Field' (CIF). Implementing the control loops with CIH and CIF strategies for water tank process is utilized as a case study to demonstrate the proposed analysis. The major configuration details of field devices, control strategies, and function blocks are described. Experimental results were analyzed for examining the parameter options as well as the control loop actions in response to invalid measurements to compare the safety and availability improvements between the CIH and the CIF. The proposed analysis can be useful to enable economical solutions for design phase of the FF-based control loops.