MEMS vs. Geophones: Vibration Monitoring Testing
MEMS Accelerometers Proven More Reliable at Low- & High-Frequency Vibration Monitoring
Independent, third-party lab vibration monitoring testing compared the two MEMS-based accelerometers used by the Inzwa Veva III vibration monitor to a solenoid geophone-based vibration monitor against the ISEE standard. The geophone-based device performed as the manufacturer advertised and as any field practitioner would expect, and was consistent with the manufacturer's calibration report. Both sensing technologies performed within specifications in the middle part of the range. What’s glaring, however, is the superior performance of the MEMS technology at both the lower and upper ranges of the scale:
Lower Range: at 1.5Hz, the geophone-based sensor had approximately 2dB lower response than the 40g MEMS sensor. At 1Hz, that performance gap grew to approximately 8dB – 60% lower than the 40g MEMS sensor.
Upper Range: At frequency levels above 125 Hz, performance differences as high as 24% were recorded between the different technologies, with both MEMS sensors providing more accurate readings. Also note that beyond the ISEE’s upper limit of 250Hz, the MEMS technology continued to perform better than the geophone-based sensor.