The Anti-Interference Design against Power Frequency in Multiplex High-Precision Data Acquisition System

We design a system of multiplex data acquisition, this acquisition system required not only to be run in high precision magnitude, but also to be capable of restraining power frequency interference for the case of complex application environment complex. In this paper, the advanced high-precision Σ-ΔA/D converter was introduced to be the front end of the 24bits data acquisition system and the π-type RC filter and Sinc3-type FIR notch filter were applied to restrain the power frequency interference. Simultaneously the USB2.0 bus technology was adopted with the EZ-USB FX2 controller to control A/D converter to transmit data to the upper computer for further analyzing. In the application of Corrosion Diagnosis for transformer substation Ground Grid, lab experiments and the field tests are to prove that this system can effectively restrain 50 Hz power frequency interference.