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HDC3022: Airflow Limitation in Datasheet (1 m/s Restriction?)

yamada hirot
Prodigy 10 points
Part Number: HDC3022
Other Parts Discussed in Thread: HDC3020, HDC3021

Tool/software:

Hello,
I have a question regarding the airflow conditions for the HDC3022.

In the datasheet, section 8.2.2 Detailed Design Procedure, it states that the device should not be placed in an environment with airflow greater than 1 m/s. Is this correct?
Even a weak fan seems to exceed this condition, which feels quite restrictive in practical applications.

I am considering using the HDC3022 in an air conditioning duct, where the airflow is around 10 m/s.
Could you please advise up to what airflow level this device can actually be used?
Also, are there any differences in airflow tolerance among HDC3020, HDC3021, and HDC3022?

Additionally, the datasheet mentions that noise increases with higher airflow.
Could you explain what kind of noise occurs in this case?
For example, does it cause measurement errors, unstable readings, or extreme values such as 0% RH?

Thank you

  • 0
    TI__Genius 11985 points

    Yamada-san,

    The HDC3x can be used in any airflow speed, but its RH performance can be negatively impacted by higher wind speeds. Higher wind speeds will lead to increased noise, which means the measurements will become unstable. The HDC3x wont have digital RH error glitches like dropping to 0% randomly, but the RH will not stabilize well and you may see moving RH values of several %RH. When the tape is removed from the HDC3021, it is functionally equivalent to HDC3020. So you should expect no difference between those two. The HDC3022 has a slightly slower response time due to the filter cover, so it may actually appear as more stable because it cannot respond quite as quickly to the volatile changes in RH/Temp that are present in a high air flow environment.

    Regards

    -Alex Thompson

  • 0 in reply to Alex Thompson
    Prodigy 10 points

    Thank you for your prompt response.
    Could you please let me know if there is any statement in the datasheet or related documentation that indicates the device can be used under any airflow conditions?
    In order for us to adopt this device, we need documentation or references that clearly support this point.

    Does the product lifetime change depending on the airflow speed (for example, 1 m/s, 10 m/s, or 20 m/s)?
    Also, does airflow have any impact on the long-term drift characteristics?