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HDC1080: When should we turn on the heater of HDC1080?

weiji jiang
Expert 2040 points
Part Number: HDC1080


Hi TI Folks,

  Good day to you.

  My customer has question on the heater of HDC1080, refer to datasheet ''HDC1080 Low Power, High Accuracy Digital Humidity Sensor with Temperature Sensor (Rev.A)" Page No.9 (chapter 8.3.3):

1. drive condensation off the sensor.

2. helps in reducing the accumulated offset after long exposure at high humidity conditions.

3. Once enabled the heater is turned on only in the measurement mode. To accelerate the temperature increase it is suggested to increase the measurement data rate.

   Please teach on above three items:

1. How to understand / judge there is condensation on the top of HDC1080?

2. What kind of "high humidity conditions" need to turn on the heater, and how to judge the triggering level of "high humidity conditions" ?

3. Does it mean the temperature / humidity result should be ignored during the heater is turned on, because it's not the real environment data due to heat up. And please advise that estimated how long will the sensor return back to ambient situation. 

best regards

Jiang WeiJi

  • 0
    TI__Expert 5145 points

    Hi Jiang,

    1. The HDC1080 is able to auto detect the condensation, because in this condition the device output suddenly drop from about 100% to 0% (this is not physically possible, so it indicates that there is condensation). The heater should be switched on when the output suddenly fall from about 100% to 0%, and switched off when it suddenly rise from 0% to about 100%;
    2. For high humidity conditions we intend conditions above the recommended humidity operating range (>70%). Long exposure outside the recommended operating conditions may temporarily offset the RH output. This offset is slowly recovered when the device is brought back to the recommended operation conditions. With the use of the heater, this offset can be recovered slightly more quickly.
    3. Yes, correct. When the heater is ON the humidity and temperature measured by the HDC1080 do not represent the real environment conditions.

    Please let me know if you have any doubts or need further support.

    Best regards,

    Carmine

  • 0 in reply to Carmine Iascone
    Expert 2040 points
    Hi Carmine,
    Good day to you.
    Thanks for your details explanation.

    best regards
    Jiang WeiJi
  • 0 in reply to weiji jiang
    Prodigy 50 points

    Hello,


    I'm interested in this discussion.

    I intend to use the HDC1080 to monitor outside temperature, so it will be permanently outside, exposed to high and low humidity.

    From previous post, I understant that using heater could be a good pratice above 70%

    Then, as the heater will make measurements a bit false, do you have some recommanded timings for that ?

    I mean:

    1- Enable heater and perform x measurement during y seconds (also considering it may be some condensation).

    2- Wait for z seconds before considering measurements as good ("cool down" delay).

    Any clue about x, y & z values ? 

    Best regards,

    Fred