Interacting Temperature and Level Control

This is an experiment that demonstrates the control of a multi-input multi-output (MIMO) process. Both hot water (from a variable power electrical heater) and cold water are fed into a through their individual control valves. The flow from the tank is set by positioning a manual valve. The level in the tank is controlled by the cold water valve and the temperature in the tank by the hot water valve, using two separate controllers. The effects of interaction in this 2x2 multivariable system are explored. The instrumentation is electronic temperature, flow and level sensors and single-station micro-processor temperature and level controllers.

Control techniques studied:

• Mathematical Modeling
• Sensor calibration and actuator characterization
• Ultimate-gain and ultimate-frequency Ziegler-Nichols PI tuning
• MIMO feedback stabilization