Analysis of macrocycle schedules for an alternative of FF-based feedforward control

Abstract

This paper focuses on analyzing the macrocycle schedules generated for an alternative implementation of Foundation Fieldbus (FF)-based feedforward control with hybrid architecture. The interested alternative control strategy is based on the use of the bias/gain (BG) function block to create feedforward summing function outside a proportional-integral-derivative (PID) function block for use to meet special operation requirements. An FF temperature control loop connected to the DeltaV distributed control system (DCS) providing built-in capability to execute function blocks in an H1 interface card is utilized as a case study to examine the effects of eight different configuration schemes on macrocycle schedules and function block synchronizations. Experimental results obtained from major configuration schemes by placing the PID block in the DCS host controller, the H1 interface card, and the temperature transmitter show that function block allocation affects the control performance to anticipate process disturbance effects.