Coefficient diagram method based control for two interacting conical tank process

All real word process are nonlinear in nature, control of such process is still challenging. Two interacting conical tank process is a one such nonlinear process. First order plus dead time model obtained from process. In this paper coefficient diagram method combined with PI controller. Robust controller is designed based on stability index and equivalent time constant which is related to polynomial of process and controller. The servo and regulatory response of CDM based PI and ZN based PI compared and investigated.