Data Acquisition from Capacitance Sensor AD7746 to Central Monitoring System Using I2C Protocol

Abstract: Data acquisition involves gathering signals from various measurement sources and digitizing the signals for the purpose of storage, analysis and presentation at a central monitoring system. Data acquisition system comes in many different PC technology forms to offer flexibility when choosing the system. We can choose from PCI, PXI, PCI express, PXI express, PCMCIA, USB, wireless, I2C and Ethernet data acquisition for test, measurement and automation applications. Data acquisition is the process of sampling signals that measure real world physical conditions and converting the resulting samples into digital numeric values that can be manipulated by a computer. Data acquisition systems typically convert analog waveforms into digital values for processing. The components of data acquisition systems include: Sensors that convert physical parameters to electrical signals and Signal conditioning circuitry to convert sensor signals into a form that can be converted to digital values. Data acquisition applications are controlled by software programs developed using various general purpose programming languages such as C, FORTRAN, Java, Lisp, Pascal and VHDL. Our project essentially deals with analysis of these samples collected by capacitance sensor from various points of the test mass. The analysis is performed using an accelerometer AD7746 which measures the capacitance and converts it to a digital data .This data is then transferred onto a register block module using the I2C interface. Later it is displayed on a PC for further analysis.

Keywords: Accelerometer AD7746, I2C, SDA, SCL, Decoder, Registers