Application of Matlab and Simulink to a Low-Lift Sump System

Abstract

This paper describes the application of a computer-aided control system design (CACSD) tool known as Simulink. Simulink is a modern non-linear dynamic simulation tool and forms an extension to Matlab,* adding many features specific to dynamic systems. The application of Simulink to a water treatment works pumping station is outlined. The objective is to enable a complex simulation model of the plant (block diagram descriptions), including all relevant process dynamics, to be easily built up. Using this simulation model a control strategy is designed to maintain the water level in a two well sump within a specified operating band. The level constraint has to be met irrespective of inflow transients due to filter washes, surges, etc. Having designed the controller based upon plant model simulations, the control algorithms were coded in the programmable logic controller (PLC) to be used on the plant. The PLC was interfaced to the plant model in real time to validate the performance of the controller against the simulated plant. The application of Simulink for plant modelling and analysis proved to be successful in that a controller was easily designed and implemented, and exceeded the performance specifications.