抄録
This paper first shows the timing analysis of the fieldbus control system (FCS) by considering both communication and control tasks at the same time. As a result, the fieldbus control loop time is formulated, and the condition of the loop operation is represented with the loop time in the FCS. Then a modified PID control algorithm is proposed to overcome varying communication delays. Finally, a fieldbus control loop is modeled and simulated to validate the timing analysis and the control algorithm. The simulation results show that the control algorithm works well for the common processes having a first-order model with dead time and the stability of the fieldbus control loop can be assured under the unpredictable and varying time delays caused by the fieldbus.
