Laboratory Experiments > Three Tank System > Brief Description

TTS20 Three-Tank-System

The laboratory experiment "Three-Tank-System TTS20" includes the technical realization of a nonlinear multi input- multi output system (two inputs, two outputs) with two actuators and a digital controller (non- linear control and decoupling).

The nonlinear controlled system consists of three plexi-glass cylinders T1, T2 and T3 with the cross-sectional area A which are interconnected in series by two connecting pipes. The liquid (distilled water) leaving T2 is collected in a reservoir from which pumps 1 and 2 supply the tanks T1 and T2. All three tanks are equipped with process pressure transmitters for measuring the level of the liquid. A digital controller controls the flow rate Q1 and Q2 such that the levels in the tanks T1 and T2 can be preassigned independently. The level in tank T3 is always a response, which is uncontrollable. The connecting pipes and the tanks are additionally equipped with manually adjustable valves and outlets for the purpose of simulating clogs as well as leaks.

The documentation of the Three-Tank-System includes sections for assembly and start-up, the technical data, the theoretical background, the mathematical model of the plant as well as guidelines for the practical course with solutions.

The Three-Tank-System TTS20 qualifies for use in research projects in nonlinear control and fault diagnosis. The standard version of the TTS20 already contains a electrical disturbance unit which allows the simulation of eight different faults affecting the sensors, the plant and the actuator. For the three sensors total failures can be simulated by switches while scaling errors can be adjusted by potentiometers. A variation of the actuator amplification can be achieved by attenuating the control signals for the two pumps. The attenuation can be adjusted using potentiometers. The last manipulations simulate two further component failures besides the mentioned clogs and leaks.

Using a prototype of the TTS20, researchers in the department of measurement and control at the University of Duisburg have successfully tested methods of nonlinear decoupling and model based fault diagnosis. For such advanced research projects the following options are available:

The Option 20-02 extends the basic version of the TTS20 by the plug-in card MF634 for a PC with PCIe slot. The associated practical course program running under WINDOWS (WINDOWS 7-10) is designed for engineering student laboratories or demonstrations. The adjustment of controller parameters, the determination of characteristics or the recording of step responses with respect to setpoint changes or disturbances can be selected by means of a menu.

The graphic output of recorded data may be sent to a window. Its content may be printed, saved as a WMF file or copied into the clipboard.

The described laboratory experiment is suitable for students at all levels of process control engineering.

By means of the PC plug-in card MF634 of Humusoft the laboratory experiment "TTS20 Three-Tank-System" can easily be integrated in Matlab/Simulink with real-time environment. The user now has the opportunity to test its own controller designs under Matlab/Simulink.

With the Option 20-03 a standard controller program in C++ source in combination with library routines for graphic output, controlling the sampling period as well as controlling the PC adapter card is available. The controller program can be modified by the user for research purposes. The Input/Output routines contain among other things the driver for the A/D-D/A converter card, which comes with Option 20-02. The range of functions and operating possibilities of the standard controller program is equivalent to the above mentioned practical course program. The Embarcadero C++ Builder V10 is required.

As extension for the laboratory experiment "Three-Tank-System TTS20" the following options are available:

  • Option 20-04 Software extension to control the electrical control valves incl. additional A/D-D/A card for PC with PCIe slot (requires Opt. 20-02, Opt. 20-07, Opt. 20-09).

  • Option 20-07a Electrical control valve as coupling valve between the tanks with potentiometer output.

  • Option 20-07b Electrical control valve as drain valve with potentiometer output.

  • Option 20-09 Complete Adapter Box to connect up to six control valves (Opt. 20-07) to a PC.

Technical data are subject to change (Date 18-December-2018)