The Design Of Tanks Liquid Level Measurement And Control System

With the continuous development of microelectronic technology, the demand of measurement accuracy and automation degree of liquid level, especially the measurement of liquid level in the environment of high-temperature, high pressure, strong acid or strong alkali, not only the sufficient accuracy must be assured, but the safety and reliability must be paid more attention. This thesis- the Design of Tanks Liquid Level Measurement and Control System is put forward on the basis of this background.First, methods of measuring the tank liquid in current days are introduced. Aiming at the faults such as the low measurement accuracy, low reliability, poor maintainability and non real-time, etc, a feasible scheme is brought up. The whole tanks liquid level measurement and control system is divided into four modules, which are expounded respectively in separate chapters and sections.The focus point of the thesis is the design of weighing sensor. In a modern automatic detection system, if there are no sensors, various parameters of each part in the process of production would not be monitored or controlled, the automatic control would not be achieved either. So the design of sensor is especially important. The design process of weighing sensor is discussed in detail in the thesis.Hardware design of the wine tanks level includes OP07 Differential Amplifier, ICL7135 Analog to Digital Conversion Circuit, ISP Download Circuit and MCU Expanding circuits. Each circuit is of high reliability and convenient for maintenance for using modular design.The part of the power supply design. Because in the stable power design, stable power is needed in all kinds of IC in sensor bridge circuit, Amplifier circuit and A/D converter circuit, the voltage is different, interference must be avoided as possible, and positive and negative power is needed in some IC. In response to these requests, practical stable power is designed.Modules design is used in the part of the application software, divided into eight modules. Such as the A/D conversion program, I/O conversion program, Human-Computer interface program, alarm level setting program, reduction program, the weight of tanks setting program, zero clearing and reset program, serial communication program and the main program.The design of circuit of this system is universal, which can be applied to other level or non-level measurement system.