Highly synchronized, simultaneous, high-speed 24-bit data acquisition of triaxial MEMS accelerometers for monitoring a real world civil structure

A hardware system has been developed to obtain data from multiple MEMS triaxial accelerometers for structural health monitoring research in a laboratory setting. The system can be easily configured for a single accelerometer or up to as many as 120 triaxial accelerometers with 24-bit data sampled up to a 2 kHz rate simultaneously. The system is modular where each Aggregator Module consists of a circuit board that supports up to eight accelerometers. Up to 15 modules can be synchronized to within 0.1 µs for simultaneous data acquisition and timestamping by connecting a central clock module that distributes a 10 MHz clock to each Aggregator Module. This represents (4 channels per ADC) × (8 ADCs) × (15 Aggregator Modules) = 480 channels that are all simultaneously sampled and synchronized down to 0.1 µs. The data from each Aggregator Module is transmitted to a single host computer or multiple host computers using serial communication. The advantages of this custom system over a wireless solution are its very tight synchronization, high sample rate, high resolution and ability to process large quantities of data. COTS wired solutions do offer these features; however, to accommodate 480 sensor channels, numerous bulky and expensive pieces of equipment are needed. We decided that a custom design allowed us the greatest performance in a scalable, lower power, portable and affordable package.