Low-Cost Condition Monitoring System for Smart Buildings and Industrial Applications

Condition Monitoring (CM) aims at damage identification through the measurement of various data collected from the systems under investigation (civil structures, mechanical parts, or industrial machineries) such as acceleration, temperature, displacement, and dynamic properties variation. Synchronization between the measured signals is mandatory for the processing of diagnostic metrics and modal analysis, which is why most of the monitoring systems today consist of a centralized acquisition unit to which analog transducers are connected. However, this solution entails a high cost of equipment and the use of long analog cables for each transducer. A full-digital network solution has been developed to solve these problems. The acquisition network is composed of Interface Boards for interfacing with the data storage system (e.g., a personal computer) and Acquisition Nodes integrating Micro Electro-Mechanical Systems (MEMS) digital triaxial accelerometers. The Interface Boards can be connected via Universal Serial Bus (USB) or Local Area Network (LAN), while the Acquisition Nodes are connected in daisy-chain via a digital bus implemented on an Unshielded Twisted Pair (UTP) cable. The proposed solution simplifies wiring, reduces system cost, and provides accurately synchronized signals. Experimental measurements on a truss model and a motor test bench for ball bearing failures diagnostic are presented, to demonstrate the effectiveness of the solution in civil and industrial applications, compared to a traditional analog laboratory-grade system.