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HDC2080: What will happen in case of RH reached beyond 100%

SUMIT RANJAN
Expert 2005 points
Part Number: HDC2080

Hi Team,

I was doing testing of device with Bath chamber (Methanol Liquid to see accuracy of sensor) and found that devices was showing temperature and RH always 0.0C and 0% respectively. at chamber temperature of 0C, -15C. 

After checking its recorded log and found that after RH of 98% it stopped to show temperature data and humidity.

So, my question, this is known thing and this will happen beyond 100% RH?

  • 0
    TI__Mastermind 28075 points

    Hi Sumit,

    Thank you for your post. The HDC2080 should only be operated in a non-condensing environment per the datasheet. A 100% RH environment typically indicates the presence of condensation.

    If you have submerged the sensor in a methanol solution then it is likely that the RH sensing polymer has been damaged. We have seen similar behaviors from pouring liquid water directly on the sensor opening of the HDC2080.

    Best Regards,
    Brandon Fisher

  • 0 in reply to Brandon Fisher94
    Expert 2005 points

    Hi Brandon

    Ok, I have finding same issue with RH less than 0%. Actually i have covered HDC2080 with thermal pad to get more accuracy on temperature sensor.

    Basically, we have arrangement like below:

    first metal we have which is exposed in outside environment and then we are using thermal pad between metal and HDC2080 Ic so Ic is fully covered with thermal pad. in that case, Humidity will not work.

    So, in methanol testing it is going high on more than 100% i guess, i can;t read beyond this and while keeping in normal freezer then it is going less than 0% RH.

    In both case, below 0% and more than 100% Temp is also coming 0.0C.

    But now, we have changed the firmware and going in temperature read only mode and in this case freezer case (less than 0%) is working fine. Methanol test will be in progress tomorrow.

    So, here my question, in case of out of range RH, temp. senor will give temperature reading independently and there wont be any issue for temperature reading only in sensor operating range?

  • 0 in reply to SUMIT RANJAN
    TI__Mastermind 28075 points

    Hi Sumit,

    SUMIT RANJAN said:
    So, here my question, in case of out of range RH, temp. senor will give temperature reading independently and there wont be any issue for temperature reading only in sensor operating range?

    Yes, the temperature reading is largely independent of the humidity reading, though the reads are typically triggered together. If the humidity sensing element has been damaged by chemical exposure or high temperature and RH I would not expect it to cause any issues with the temperature reading.

    Best Regards,
    Brandon Fisher