VECTORALAB EDGE

Sensor & Signal Acquisition

IIS3DWB wide-bandwidth MEMS accelerometer at 26.7 kHz via SPI DMA

Sensor

IIS3DWB — Wide Bandwidth Sensing

The IIS3DWB from STMicroelectronics is purpose-built for industrial vibration monitoring. Its ultra-wide bandwidth and low noise density make it the ideal front-end for bearing fault detection and rotating machinery diagnostics.

[¹] The IIS3DWB operates at a fixed 26.7 kHz ODR with a flat frequency response up to 6 kHz — well above the fault frequencies of most industrial rotating equipment.

IIS3DWB

STMicroelectronics Wide Bandwidth Accelerometer

Part NumberIIS3DWB

ManufacturerSTMicroelectronics

Axes3-Axis (X, Y, Z)

Output Data Rate26.7 kHz

BandwidthDC – 6 kHz

Noise Density75 µg/√Hz

Full Scale±2 / ±4 / ±8 / ±16 g

InterfaceSPI / I²C

Supply Voltage1.71 – 3.6 V

Signal Acquisition

Signal Acquisition Pipeline

Vibration data is continuously streamed from the IIS3DWB into on-chip SRAM via SPI DMA — zero CPU overhead during acquisition. A circular double-buffer ensures uninterrupted capture while the previous frame is being processed.

DMA Transfer

IIS3DWB → SPI → DMA → circular buffer in SRAM. Zero CPU cycles consumed during acquisition.

Frame Gating

2048-sample frames extracted with 50 % overlap (1024 samples advance) for continuous coverage.

Synchronization

Hardware timer triggers frame boundary interrupts at precise 38.4 ms intervals.

Scaling

Raw 16-bit ADC values converted to physical g-units using the IIS3DWB sensitivity constant.

Parameters

Sample Rate26.7 kHz

Frame Size2048 samples

Overlap50 % (1024 samples)

Frame Duration76.7 ms

Advance38.4 ms

Buffer Depth2× 2048 × 3 axes