Ochranný obvod pro A/D převodník

Abstract

This Master’s thesis presents the design and implementation of a signal conditioning and protection analog interface for an AD converter (ADC), optimized for measuring welding voltage waveforms in CMT welding technology. The focus is on development of a measurement interface between the signal source and the ADC that provides voltage level attenuation and filters the wanted frequency spectrum. It also provides overvoltage protection for the ADC, eliminating the negative effects of transient voltage spikes caused by power transistor switching within the signal source. The circuit also offers a variable input range to utilize full resolution of the ADC's range, controlled by a microcontroller (MCU) running custom made firmware, which handles gain switching based on a custom control algorithm for welding phase synchronization via digital signal. MCU also communicates with a custom PC program via a proprietary serial protocol.