A portable measuring system including an electronic acquisition device, at least one sensor linked to the acquisition device, and a power supply module. The power supply module includes at least one electric torus to be mounted on electrical wiring in order to generate a current by induction, and an electric power management device that delivers a voltage-stabilized current in order to power the acquisition device. An assembly includes an external data centralizer. Such a system or assembly is easy to install, has potentially unlimited autonomy, and is particularly well suited to use in an aircraft.