When faced with testing scenarios involve with
either relative motion between components of interest or large physical
dimensions, distributed measurement systems offer a way to accomplish the
measurement task. In these situations, a cluster of small battery powered
devices can offer the most efficient solution.
A wind turbine demonstrates both testing
scenarios. Combining strain measurements on the turbine blades with stresses in
the gearbox calls for relative motion testing, while testing the noise generated
by the turbine will require you to measure large areas. Another interesting
example is the use case of wide area beaming forming for the analysis of
passenger jet fly-overs. These systems can have diameters on the order of 140 m
with over 400 microphones.
To handle the physical and data rate
implications of a system like this, it is wise to consider multiple acquisition
units synchronized using either fiber optic VME synchronization or a one-wire
solution of IEEE 1588-2008 (PTP) with PoE providing both synchronization and
power with a single cable.