Limitations of MEMS Accelerometers

Our testing and analysis shows that MEMS accelerometers can create erroneous data directly related to the frequency and amplitude content of the vibrations being recorded. 

Introduction

Micro-Electro-Mechanical Systems (MEMS) are appearing in vibration monitoring equipment in numerous industries including industrial, construction and blasting.
Instantel recently completed extensive testing comparing current MEMS accelerometers against traditional solenoid geophone sensors.

Our tests confirm that MEMS accelerometers contain significant uncertainty in the validity of their recorded data where vibrations with high frequencies (1,000+ Hz) are dominant. In several of our tests, the MEMS accelerometers registered erroneous amplitudes 19 to 45 times higher than the solenoid geophones (see Figure 1). Sources of highfrequency vibrations include heavy equipment, jackhammers, pile drivers, hoe rams and explosives.

For full documentation of Instantel's tests, please download the white paper below.

Conclusion

Our testing and analysis shows that MEMS accelerometers can create erroneous data directly related to the frequency and amplitude content of the vibrations being recorded.

High frequencies can affect the accuracy of vibration levels reported by MEMS accelerometers. As it is impossible to predict the exact frequency and amplitude content that a project will produce, this uncertainty jeopardizes the ability to record data accurately and reliably. Our lab observed a strong correlation of high frequencies being a source of data inaccuracy when MEMS accelerometers were used.

While MEMS accelerometers are alluring for their installation flexibility, they clearly do not match the reliability of solenoid geophones. In our opinion, the benefits do not outweigh the risks of recording inaccurate or false data which could result in fines, project delays or shutdowns, or litigation for not adhering to vibration standards or regulatory limits.

Vibration equipment manufacturers must be able to provide proof that their equipment meets compliance standards. We highly recommend that contractors and property owners request these proofs and review them prior to selecting a vibration monitoring system.

Instantel will continue to monitor MEMS technology for advancements that address the above issues.

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