JIC_V2_N1_RP3 D. Marshiana Thiru Sakthi Murugan P. Journal on Instrumentation & Control Engineering 2321 – 1148 2 1 23 28 Nonlinear system, Mathematical modeling, Fractional Order PI Controler Technique (FOPIC), Proportional Integral Derivative (PID) Fractional Order PI Controller Technique (FOPIC) offers success due to emerging of effective methods in differentiation and integration of the no integer order equation. In this research, the controller design using FOPIC is determined for a nonlinear system. The nonlinear system is taken up for the study is a spherical tank which is approximated to a first order system. Simulation is made by the MATLAB software. November 2013 - January 2014 Copyright © 2014 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=2789