Study Of Impedance Measuring Device Of Transducer

The impedance characteristic is an important parameter reflecting the performance of the transducer,and it has important guiding significance for the design of the transmitter and receiver.Usually the standard impedance analyzer can only be measured under open and normal environmental conditions,while it is difficult to carry out special conditions such as high pressure and very low temperature.This paper will study a self-capacitive impedance tester,which is used to meet the special requirements mentioned above.This article elaborates the research and design of the tester from two aspects of hardware and software.In the hardware design,the hardware circuit system is composed of the ADuCM350 subsystem and the DSP subsystem.The main function of ADuCM350 subsystem is to complete the impedance measurement.The subsystem is based on ADuCM350 as the main control chip and builds its peripheral circuits,such as program download circuit,power supply circuit and impedance measurement circuit.DSP subsystem controls peripheral modules to store measurement data and detect external environment.The subsystem takes TMS320VC5509 A as the main chip,and completes the design of surrounding hardware,such as serial communication circuit,SD card access circuit,clock circuit,temperature detection circuit and power circuit design.The two subsystems work together through the I2 C bus.In software design,this paper introduces the functional software setup and impedance measurement software design flow of each module of impedance measurement AFE,and analyzes the optimization of impedance measurement program parameters.This article describes the parameters of the software settings and workflow in amperometric/potentiostat measurement.In addition,this article describes the implementation of I2 C read and write operations,data storage and file creation and read and write based FAT32 file system.Finally,the parameters selection of the macro definition are verified by an example,and the measurement of amperometric/potentiostat is carried out and compared with the theoretical value.,the design can also be achieved on the RC time constant measurement.For the measurement of resistance,inductance,capacitance and RLC series circuit which analog transducer equivalent circuit,the measured value is calibrated in advance on the software program,and the result of the output is compared with the standard value.The impedance measurement of the transducer is carried out,and the results of the measurement are analyzed and adjusted.The analysis shows that the measurement system can work steadily and achieve the accurate measurement of transducer impedance in the low frequency band of 1-50 kHz.