OASIS: Open Acquisition System for IEPE Sensors: For Academic Research and Teaching Purposes

Expensive measurement equipment often inhibits students from gaining practical experience with vibration measurements. The commercially available, proprietary hardware and software additionally does not grant insight into the used algorithms or allow modification and expansion. Both issues are overcome with the use of community developed open-source designs. This chapter discusses the requirements for vibration measurements in an academic context, like sampling frequency or resolution and especially synchronicity. These requirements are derived and incorporated into the design of an open-source data acquisition board for IEPE sensors (OASIS). The design is focused on the use of commonly available parts and a broadly community supported micro-controller (ESP32 family), with the costs bounded below 100 euro. The built acquisition system offers four channels for IEPE signals, which can be sampled with up to 20 kHz and 16-bit resolution continuously. Additionally, wireless synchronization of multiple data acquisition boards is provided. This allows for use cases on systems with partly rotating structures, e.g., wind turbines, where synchronous measurements of stationary and rotating parts are necessary. The here-proposed approach does not rely on external clocks, like GPS or network services. An experimental validation shows that it is possible to synchronize two systems using this approach with a delay that is less than 100 µs.