How is ST recommending the use of MEMS Accelerometer for Vibration Sensing applications with Sensor Resonant Frequency as low as 2.4kHz for ISM330DCHX & similarly others?

Chubs · ‎2023-05-19

I am surprised to see half of the MEMS sensor datasheet do not mention sensor resonant frequency. Sensor Noise values feel misleading as we have no clue what noise are we going to receive in our shipment. Also, noise levels are not documented well either.

Is ST purposely misleading product designers into choosing their MEMS sensors?

I am surprised how can one use a 2.4kHz resonant frequency sensor in industrial vibration sensing applications.

Federica Bossi · ‎2023-05-22

Hi @Chubs,

Welcome to St Community!

The characteristics of each sensor depend on the application they are made for.

ISM330DCHX is a 6 axis module and so has two sensor combined in one package, so this requires trade off.

If you are interested in a sensor designed specifically for vibration sensing I suggest you to look at our IIS3DWB, a ultra-wide bandwidth and flat frequency range from dc to 6 kHz (±3 dB point).

In addition, the noise levels you found in our datasheet don't refer to the noise applied but to the noise of the data read from the output registers.

Hope these explanations can change your perspective about ST products. If my reply answered your question, please click on Select as Best at the bottom of this post. This will help other users with the same issue to find the answer faster :)

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

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Federica Bossi · ‎2023-05-22

Hi @Chubs,

Welcome to St Community!

The characteristics of each sensor depend on the application they are made for.

ISM330DCHX is a 6 axis module and so has two sensor combined in one package, so this requires trade off.

If you are interested in a sensor designed specifically for vibration sensing I suggest you to look at our IIS3DWB, a ultra-wide bandwidth and flat frequency range from dc to 6 kHz (±3 dB point).

In addition, the noise levels you found in our datasheet don't refer to the noise applied but to the noise of the data read from the output registers.

Hope these explanations can change your perspective about ST products. If my reply answered your question, please click on Select as Best at the bottom of this post. This will help other users with the same issue to find the answer faster :)

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

Chubs · ‎2023-05-22

Hi @Federica Bossi,

Thank you, I am glad to get to explore ST product lineup. Though I am liking most of the portfolio, these MEMS Accelerometer & the datasheets threw me away.

I understand there are tradeoffs, what I don't get is why mention Condition Monitoring/Vibration Monitoring in the application section to begin with. Or at least ST engineers should make an appropriate note citing the low resonant frequency. To me, this is utterly misleading newbies into making decisions that shall for obvious reasons turn out to be disastrous on the field.

Look forward to trying the IIS3DWB, I have already ordered a few of them. Apart from IIS3DWB, there seems to be no MEMS sensor in the STM portfolio that has a Resonant frequency higher than 5.5kHz,