
The NI DAQ card is used as the interface between hardware and software. PID Controller controls the water flow rate through solenoid valves to maintain the required levels in both tanks. It is available in analog and digital forms. The PID Controller is usually used as temperature, motion and flow controllers. In addition, capacitive-type probe level sensors have been used to monitor the level of water in each tank. At the base of each tank, two flow valves (one as regular disturbance and other as leakage) connected to reservoir. Each of both small tanks has independent pumps to pump water into the top of each tank. The current work uses solenoid valves as actuators including of two small tanks mounted above a reservoir which functions as storage for the water.


A lot of industrial applications of liquid level control are used now a day’s such as in food processing, nuclear power generation plant, industrial chemical processing and pharmaceutical industries etc.
