A minimal hardware implementation of a high speed ERT system and a demonstration of its capabilities
ISPT6 paper on a further-simplified UCT current pulse ERT system. The primary ERT functions are compressed onto two double-sided circuit boards, with sub-1 mV noise under lab conditions, demonstrated on a 290 mm bubble column for minerals-flotation applications.
Summary
This paper describes a further refinement of the UCT current pulse ERT instrument. The primary ERT functions are compressed onto two double-sided circuit boards: a 16-channel amplifier with sample-and-hold, and a current source plus multiplexer board. Both are driven by a Freescale GB60 micro-controller, a commercial USB DAQ, and an Intel Atom embedded PC for real-time reconstruction. Acquisition runs at 850 frames/second from a single 16-electrode ring, or at a proportionally reduced rate across up to four rings. Noise drops to below 1 mV standard deviation under lab conditions, and the system is demonstrated on a 290 mm bubble column, using ERT together with an optical capillary probe to characterise gas distribution and bubble size for minerals-flotation applications.
Context
This paper sits in the middle of a multi-year involvement with Bill Randall's current pulse ERT programme at UCT, and was presented at a symposium hosted in Cape Town itself. It is where the hardware simplification really started to bite. Two circuit boards instead of a rack of modules, with the noise floor pushed down enough that the system could be trusted on a live bubble column. The broader engineering pattern it set up is one I still return to: keep the architecture legible, make the interfaces explicit, and make the system usable in the real world rather than only in theory.