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HDC3021-Q1: Regarding vents are blocked by condensed water droplets

PYTsai
Genius 10515 points
Part Number: HDC3021-Q1
Other Parts Discussed in Thread: HDC3022, HDC3020, HDC3021

Tool/software:

Hi 

If before powering on the product, the vents are blocked by condensed water droplets.

What would the temperature and humidity readings be like after powering on in this situation?

Will it still be able to read the ambient temperature and humidity?

How about if the above case happen with the HDC3022?

  • 0
    TI__Intellectual 2290 points

    Hello PY,

    This would really depend on time. How long do you expect the device would have water on it? For the HDC3020 when the device initially gets a drop of water in the cavity, the RH reading will drop to 0% and then eventually the device would like read ~45% RH and if you tried to dry the sensor cavity with a cotton swab/stick, you may see the readout jump up to 90% RH before it begins to subside to nominal values.


    For the HDC3022, again, this would be time sensitive, but also dependant on the environment (high temp, high humidity for example). If the water remained on the sensor long enough (hours in some cases), the water vapor may eventually permeate the filter and condense causing a rise in RH readings (though not as high as a filterless HDC3020).

    There shoudln't be any impact on the temperature sensing portion of the device.

    What is the end application?

    Hope this helps,

    Harry

  • 0 in reply to HarryG
    TI__Genius 10515 points

    Hi Harry,

    Do you mean, for HDC3022 the same, if there is a drop of water on the "HDC3022" sensor, the relative humidity initially will drop to 0%, then rise to about 45%, and after removing the water droplet with a cotton swab, the relative humidity shows around 90% and gradually decreases to the standard value?

    Is it HDC3022 got the same performance comparing to HDC3021 when affected by condensation water ?

    Would you share the advangate of HDC3022 vs HDC3021 ?

    Thanks!

  • 0 in reply to PYTsai
    TI__Intellectual 2290 points

    Hello PY,

    The HDC3022 would have a slightly different behavior than the HDC3020. As stated above, the HDC3022 would eventually condensate after a very long period of time, but it would take much longer than the HDC3020, and it would be more of a gradual increase in RH as well (compared to the HDC3020).

    If condensation is a concern, I would suggest running the heater in the part (regardless of filter/no filter) to bake out any moisture/condensation.

    In regards to the HDC3022 vs HDC3021, the HDC3021 has a tape cover that would allow the device to be conformal coated, but the tape cover would need to be removed after the conformal coating process, exposing the sensor cavity much like the HDC3020. So in this case the HDC3022 would be more suitable if direct water exposure is expected due to its IP67 water filter.

    Here is a document that can hopefully provide some additional information for choosing between the two: https://www.ti.com/lit/an/snaa346/snaa346.pdf

    Please keep in mind regarding the filter, the membrane may not filter gaseous contaminants, such as outgassed VOCs.

    Regards,

    Harry