Measurement And Control System Optimal Design And Experiment Of Multi-parameter Water Quality Monitor

Water quality detection is the basis of water environmental protection and management, multi-parameter water quality detection is one of the important development directions of water quality monitor equipment. The measurement and control system design of multi-parameter water quality monitor is the core technology to make an intelligent, automatic, networked instrument. And it’s the key to make instrument work stable and automatically. Therefore, this research is of important research significance.Aiming at the problems existing in the measurement and control system of the multi-parameter water quality monitor which is preliminary-developed by microsystem research center of Chongqing University, this paper analyzed the structure, operating principle of the instrument. Combing with the current development trend of water quality detecting instruments, this paper presented the improvement of the measurement and control system based on Raspberry Pi control platform. This paper designed the sample reaction and detection module, sequent inject module, self-detection module, power management module, embedded control platform based on Raspberry Pi and so on, designed the measurement and control system motherboard PCB, built the system testing platform successfully, completed the commissioning of each module of the measurement and control system, completed the experiment of cleaning and water quality parameters testing. Results of the experiment showed that the measurement and control system based on Raspberry Pi has stronger stability, reliability, and meets the demand of instrument application.The main work is as follows:① The status of water quality detecting instrument at home and abroad was researched. Analyzing the problems existing in the measurement and control system, combing with the current development trend of water quality detecting instruments, the overall optimized project was presented.② Based on understanding the structure and working principle of the original multi-parameter water quality monitor, existing problems of its measurement and control system were analyzed, and the optimizations for the sample reaction and detection module, sequent inject module, self-detection module, power management module, embedded control platform were designed.③ This paper realized the control to each module of the measurement and control system.The functions of bubble disturbing, cleaning, discharging, constant temperature control were realized for the sample reaction and detection module, and the strength of bubble disturbing can be switched. The sequent inject and the self-detection circuit were designed, and this paper realized the leakage self-checking, power-off protection, chassis temperature control.④ The embedded platform which based on Raspberry Pi was completed, including the development environment, wiring Pi library development, touch screen, remote control. The hardware resources of measurement and control system can be controlled through GPIO, USB and I2 C interface on Raspberry Pi board.⑤ This paper completed the debugging of the motherboard of the measurement and control system, built the system testing platform, completed the commissioning of each module, completed the experiment of cleaning and water quality parameters testing.