Measure And Control System Design And Experiment Of Multi-parameter Water Quality Detecting Instrument

Water resources protection and management have received universal attention allover the world, water quality testing equipment is an important technical and means tocomprehensively reflect the water quality and help making related countermeasures.Based on that, to develop a portable, low-cost, multi-parameter water quality inspectionequipments which can realize real-time fast monitoring have become the hot spot ofdomestic and international research, and with great strategic significance and urgentapplication requirements.According to the overall design requirements of multi-parameter water qualitymonitor which is based on micro spectrometer, this study carried out research on themeasurement and control system of multi-parameter water quality monitor. Based onstudying the research situation of water quality inspection equipment and analyzing thestructure and working principle of micro-spectrometer based multi-parameter waterquality monitor, this paper puts forward a function-module based overall design schemeof carrying out system control. Break through the key technology of parameters waterquality inspection, such as the realization of flow control and online samplepretreatment control (e.g. accurately automatic injection, automatic constanttemperature control, automatic cleaning, ultrasonic auxiliary digestion), and completethe machine alignment debugging and application experiment test research. the resultsindicate that the machine’s performance indicators could meet the design requirements,and the national standard contrast test result shows that the performance indicators haveall reached the practical requirements. The main works of this study are as follows:①Analyze the domestic and international research status of the measure andcontrol system of on-line multi-parameter water quality monitoring. To satisfy therequirements of multi-parameter, automation and integration, this paper puts forwardthe whole measure and control system design project of the water quality monitor②According to the characteristics and requirements of the instrument’s flow pass,design a multi-sample, multi-reagent flow injection system on the basis of themulti-position valves and peristaltic pump, and complete of the flow control system’scircuit design;③To satisfy the instrument’s sample processing requirements before reaction, putforward a design scheme of online chemical samples retreatment control system which integrates cleaning, mixing and constant temperature control, and design the ultrasoniccleaning mixing, bubble mixing control circuit and constant temperature control circuit;④Combined with the instrument of automatic monitoring control requirements,write program of the measurement and control system, and complete thecommunication of the PC and a machine control system through the serial interfacecommunication;⑤By means of building a experimental platform, complete the machinecommissioning/debugging, and the test of sample precision, cleaning effect and theconcentration of total phosphorus’s test experiment.