Ph Concentration Meter Of The Electromagnetic Design And Realization

Acid and alkaline Electromagnetic concentration meter is an important analysis meter which is applied to measure the liquid concentration in the modern industry production process. The meter is based on the theory of Electromagnetic Induction, measure the conductivity of the liquid, and then convert to the concentration with some methods.This paper, at the beginning, reviews the development of acid and alkaline Electromagnetic concentration meters in the field of electrochemical instruments at home and abroad. Based on the previous search results, a general research and design ideas is put forward. The aim of this paper is to improve the precision of the instruments, while the reliability and its network capabilities are taken into account. Based on the mathematical model in the measurement process and with the help of circuit simulation software by Proteus, the structural parameters of the sensor are designed. Such hardware platforms as PXAG30 compatible with 51 single-chip computer and 16 bit single-chip computer with large-capacity storage space, 16 bit high-precision analog-to-digital converters AD7715, NTC thermistor with high sensitivity, 192*64 graphic Liquid-Crystal-Module MGLS19264 and SPC3 with Profibus agreement are configured. AD sampling, LCD display, an important concentration of conductivity conversion process and Profibus-dp process are compelled in the Modular software design. Meanwhile, reliability design is considered on the general planning: a hardware circuit power-filter, isolation, shielding and grounding design, the software on the digital filter design and watchdog.The special designs manifest mainly in the following two aspects:1. Make use of the circuit simulation software Proteus to design the structural parameters of the sensor which can obviously see the effect of various structural parameters. Compared to the commonly used experimental methods, this method can greatly decrease the time of design.2. Profibus-dp interface accession enriches the communication capabilities of the concentration meter. Profibus-dp field bus is high-speed, open, easy to install and maintain, which is very practical to real-time data acquisition and control by the meter installed in the production field.Generally speaking, mainly based on the reasonable designed sensor parameters, the accuracy of measurement is improved. So, this paper detailed analyses the selection process of the sensor parameters, use Regression method to select the important frequency parameter, finally, a better input and output curve was get. Electromagnetic concentration of acid-base analyzer designed to ensure that the analyzer has small effects on the measurement. When measuring the small electrical conductivity, the output signal is very weak; the high precision and high-sensitivity chips are used in hardware circuits. Concentration of conductivity conversion process uses a fast, intuitive, and easy look-up table algorithm. In the end of this paper, experiments are made to show that the design has done well.