Modelling and Real Time Implementation of Digital Pi Controller for a Non Linear Process

Abstract

In Process industries, control of process parameters for a nonlinear process is
one of the important issues identified in literature. The nonlinear process considered for
modeling is spherical tank liquid level system. Control of liquid level in a spherical tank is
nonlinear due to the variation in the area of cross section of the level system with change in
shape. System identification of this nonlinear process is done using black box model, which
is identified to be nonlinear and approximated to be first order plus dead time model. Here
the Digital PI controller is designed using Ziegler Nicholas Tuning rule. The real time
implementation of the process is designed and implemented in MATLAB using VMAT-01
Data Acquisition Module.