Design And Implementation Of Intelligent Potentiostat Based On AVR Microcontroller

Potentiostat is an important instrument in the electrochemical tests, it can controlthe electrode potential in order to achieve the purpose of potentiostatic polarization.Potentiostat overall analysis is that a negative feedback amplifier-output system,closed loop regulation with the test electrodes, by measuring the potential differencebetween the reference electrode and the working electrode,which as a samplingsignal is compared with the control signal to achieve control and regulationpolarization current output, so that the potential difference between the referenceelectrode and the working electrode was maintained at the set of control potential. Theappearance of Potentiostat, not only solved the electrochemical reaction caused by theexternal excitation signal in the process of research value deviation, and acceleratedthe electrochemical detection and analysis of diversification. Therefore, Potentiostathas important position in the electrochemical detection system.Practical application potentiostat exist bulky, complex structure, low accuracy,poor control of constant electric potential drawbacks, limiting its scope of application.With the development of electronic technology, especially for embedded systems,in-depth application and development of chip technology, corrosion detectiontechnology can be said to be the intersection of the field of electrochemistry andelectronic fields formed a new discipline. From the practical engineering application,combined with modern electronic technology, the paper research and design of amicrocontroller based on the AVR and intelligent miniaturized potentiostat, whichwill potentiostat higher precision, better performance and stability, while meeting sitedetection needs. In this paper, the completion of the work:1. Combined with the integrated circuit technology, the paper designed astandard single-ended potentiostat circuit based on the integrated operational amplifier. The program uses an integrated operational amplifier OP27amp as thecore device, with its high input impedance, high open-loop amplification, lowoffset voltage characteristics, to effective control of the potentiostat error. Finally,the design of its hardware circuit.2. According to the three electrode electrochemical sensor of potentiostatwork basic principle, based on AVR single chip microcomputer is proposedoverall design scheme of intelligent constant potential device and implement. Thedevice adopts the high-precision D/A conversion chip ADA7705DAC8831andA/D conversion chip, the AVR microcontroller ATmega16as the control core ofthe whole system, take full advantage of its powerful high-speed processingcapability, can achieve the function of potentiostat potentiostatic set and thepolarization current parameter measurement function.3. On the ICCAVR development platform designed each functional moduleof the software; And use the ISP serial download completed the debugging of themachine.4. Finally introduced the GPRS wireless communication technology, andinto the system, to realize the remote control system. At the same time, itcombines with the RS-485communication mode, in the face of differentenvironment monitoring PC, can optionally for data transmission, thecommunication of the whole system more flexible.This system has been debugging in the laboratory.Through the data analysis, therange of allowable error in, accurate data communication, system meet the designrequirements.