Wide Bandwidth, Low Noise, Triaxial Vibration Sensor

The ADcmXL3021 is a complete vibration sensing system that combines high performance vibration sensing (using micro-electromechanical systems (MEMS) accelerometers) with a variety of signal processing functions to simplify the development of smart sensor nodes in condition-based monitoring (CBM) systems. The typical ultralow noise density (26 μg/√Hz) in the MEMS accelerometers supports excellent resolution. The wide bandwidth (dc to 10 kHz within 3 dB flatness) enables tracking of key vibration signatures on many machine platforms.

The signal processing includes high speed data sampling (220 kSPS), 4096 time sample record lengths, filtering, windowing, fast Fourier transform (FFT), user configurable spectral or time statistic alarms, and error flags. The serial peripheral interface (SPI) provides access to a register structure that contains the vibration data and a wide range of user configurable functions.

The ADcmXL3021 is available in a 23.7 mm × 27.0 mm × 12.4 mm aluminum package with four mounting flanges to support installation with standard machine screws. This package provides consistent mechanical coupling to the core sensors over a broad frequency range. The electrical interface is through a 14-pin connector on a 36 mm flexible cable, which enables a wide range of location and orientation options for system mating connectors.

The ADcmXL3021 requires only a single, 3.3 V power supply and supports an operating temperature range of −40°C to +105°C.

Applications

* Vibration analysis

* CBM systems

* Machine health

* Instrumentation and diagnostics

* Safety shutoff sensing

* Triaxial, digital output MEMS vibration sensing module

* ±50 g measurement range

* Ultralow output noise density, 26 μg/√Hz (MTC mode)

* Wide bandwidth: dc to 10 kHz within 3 dB flatness (RTS mode)

* Embedded fast data sampling: 220 kSPS per axis

* 6 digital FIR filters, 32 taps (coefficients), default options:

* High-pass filter cutoff frequencies: 1 kHz, 5 kHz, 10 kHz

* Low-pass filter cutoff frequencies: 1 kHz, 5 kHz, 10 kHz

* User configurable digital filter option (32 coefficients)

* Spectral analysis through internal FFT

* Extended record length: 2048 bins per axis with user configurable bin sizes from 0.42 Hz to 53.7 Hz

* Manual or timer-based (automatic) triggering

* Windowing options: rectangular, Hanning, flat top

* FFT record averaging, configurable up to 255 records

* Spectral defined alarm monitoring, 6 alarms per axis