When measurement instruments reach their specified performance limits, one comes to a gray zone separating reality from fantasy. Thanks to sensors, this zone is widening.
This region is approached in digital multimeters (DMMs) as the quantity being measured approaches zero. One major DMM company forces a zero reading on the display when the measurement is within a certain small band around zero. A similar issue exists in data acquisition (DAQ) systems, which are essentially multichannel DMMs.
The encroaching fantasy is being exacerbated by sensors, particularly thermocouples (TCs), which are conceptually simple sensors. When two dissimilar metals are joined, a voltage appears across their junction that is approximately proportional to temperature. Two wires -- one chromel and one alumel, for instance -- can be spot welded together at the sensing end by process chemists (who like to use TCs) and connected to the DAQ screwdown terminals, shown in orange below.
David Patterson, known for his pioneering research that led to RAID, clusters and more, is part of a team at UC Berkeley that recently made its RISC-V processor architecture an open source hardware offering. We talk with Patterson and one of his colleagues behind the effort about the opportunities they see, what new kinds of designs they hope to enable and what it means for today’s commercial processor giants such as Intel, ARM and Imagination Technologies.