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14-gram device collects data from rotating shafts
Published:  02 March, 2015

A Californian company that specialises in data-recorders and sensors for crash-testing, has come up with a tiny device that can collect data from rotating components – such as drive shafts, rotors and reciprocating rods – without needing sliprings or telemetry.

The rugged Slice data recorder, developed by DTS, weighs less than 14 grams. It is so small it can be mounted directly onto almost any moving or rotating part, without altering the dynamics. When measuring torque on a drive shaft, for example, it mounts directly onto the shaft, next to the strain gauges, thus ensuring high data quality, while eliminating issues associated with noise, data transfer and cumbersome fixtures.

The battery-powered device includes everything needed to record sensor data autonomously. A built-in microprocessor manages a signal-conditioning and storage system that includes independent excitation sources, variable gain amplifiers, adjustable sampling rates from 10–500,000 samples/s, and adjustable anti-alias filters up to 40kHz. A 16Gb direct-write flash memory can record high sample rate data continuously for hours, unlike older systems whose memory was limited to a few seconds or minutes. Attaching the data recorder to the test item reduces cabling concerns and simplifies installation.

A three-channel Slice recorder mounted on a CNC shaft, along with strain gauges to measure torque, and an angular rate sensor to measure angular velocity

The three-channel “slices” are modular, so mounting and balancing the system are said to be easy. The technology accepts inputs from bridge sensors, strain gauges, voltage inputs and temperature sensors. Because the data is stored on-board, reliability issues from streaming are eliminated, especially with higher channel counts or high-bandwidth tests. The recorders are shock-rated up to 5,000g, making them suitable for a variety of rotating applications.

DTS was founded in 1990 by three crash-test engineers. It has technical centres in the US, Australia, China, Japan and the UK.