Research And Design Of Smart Online PH Detector And Recorder

PH recorder in lieu of manual analysis saves human resources and reduces labor intensity. Instrumentation Monitoring which is excelled in peciseness, sensitivity and timeliness, continuous is very essential in modern monitoring system. Meanwhile, FCS (Fieldbus Control System) appears because of the combination of rapid developmental communication network and control system. The fieldbus intelligent instrument which adapts to FCS will become mainstreaming instrument in industrial process control system in future. So it is very essential in designing a PH detector with high precision and accuracy which is suit to fieldbusIn reseaching and designing of smart online PH detector and recorder, the main job is:1. Researching on the principle of PH detection and PROFIBUS.2. Researching on three factors which impact the accuracy of PH detector and record-solution temperature, glass electrode resistance and electrode bias.3. Linear interpolation method, impedance matching method, on-line calibration method and other methods to improve the measurement accuracy are described in theory.4. A smart online PH detector and recoder is designed which takes glass electrode as its sensor and measures acidity of solution through potentiometers.5. Designing a communication module which is adapted to PROFIBUS-DP fieldbus. The meter is designed with isolated PROFIBUS-DP series interface and standard communication protocols compatible with PROFIBUS-DP and can be connected to PROFIBUS-DP network directly.By experimenting and debugging, it proves that the Intelligent Online PH analyzer could used to measure water's PH value. It can also store data automatically and transmit it remotely with 4-20mA's standard current and PROFIBUS-DP network. This analyzer could be widely applied in online measurement of water's PH value, and will contribute the transformation from single instrument to multi-meters controlling system if future.