control-systems-principles.co.uk. Coupled Tanks Systems 1
COUPLED TANKS SYSTEMS 1
Elke Laubwald: Visiting Scientist, control systems principles.co.uk
ABSTRACT: This is one of a series of white papers on systems modelling, analysis and
control, prepared by Control Systems Principles.co.uk to give insights into important
principles and processes in control. In control systems there are a number of generic
systems and methods which are encountered in all areas of industry and technology. These
white papers aim to explain these important systems and methods in straightforward terms.
The white papers describe what makes a particular type of system/method important, how
it works and then demonstrates how to control it. The control demonstrations is performed
using models of real systems designed by our founder - Peter Wellstead, and developed for
manufacture by TQ Education and Training Ltd in their CE range of equipment. Where
possible results from the real system are shown. This white paper is about the most
common control problem in practical process systems - liquid level control. In addition to
the process industries liquid level control is found in many other places, as you will read
below. Liquid level control and modelling ideas will be demonstrated using our version of
the standard textbook system – the Coupled Tanks System. The Coupled Tanks System has
become a ‘design classic’ of control engineering teaching equipment and you can see it in
many control laboratories across the world.
1. Why Coupled Tanks Systems?
The control of liquid level in tanks and flow between tanks is a basic problem in the process industries.
The process industries require liquids to be pumped, stored in tanks, then pumped to another tank. Many
times the liquids will be processed by chemical or mixing treatment in the tanks, but always the level of
fluid in the tanks must be controlled, and the flow between tanks must be