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HDC2010: output accuracy exceeds the spec of ± 3% (MAX)

Shinichi Inoue
Guru 21686 points
Part Number: HDC2010
Other Parts Discussed in Thread: HDC1010, HDC1080,

Dear Specialists,

My customer is evaluating HDC2010 ans has a question.

I would be grateful if you could advise.

---

According to the data sheet, the accuracy is ± 3% (MAX), but an actual error is about ± 5%.

The operating range is used between 25 °C and 50 °C and there should be no problem.

Could you please let me know about possible causes.

---

I appreciate you great help in advance.

Best regards,

Shinichi

  • 0
    TI__Guru* 91206 points
    Dear Shinichi -
    What is the calibrated mechanism and method you are using to determine the hardware under test is off by +/-2%? Can you describe the conditions under which the testing is being performed?

    How many units? if more than one, are they all exhibiting exactly same behavior?

    Things we can recommend to check first here in this application, since you are operating within the temperature range of the device and seeing a slight variation in your implementation are:
    1. (from Note 11, page 5 of the HDC2010 DS) Would you please confirm the humidity range when tested is between 20% - 80% RH (non-condensing) over the operating temp range? You already stated the first post the operating/testing temp range was 25C to 50C, so that should be OK (as the range of the device is 0C - 60°C) The note further states that prolonged operation beyond these ranges may result in a shift of sensor reading, with slow recovery time.
    2. Would you also please check and confirm that no contaminants are used on/around the sensor? This can degrade the RH accuracy, too. A full list of chemicals and other good practices can be found here in an application note on the storage and handling of this family of humidity sensors from TI (HDC2010, HDC1080 and HDC1010): www.ti.com/.../snia025.pdf
    3. Then also please check and confirm that the sensor(s) has/Have not been exposed UV or visible light for an extended period of time.
  • 0 in reply to Josh Wyatt
    Guru 21686 points

    HI Josh,

    Thank you for your reply.

    I'll share your suggestion with the customer and feedback about the test conditions.

    If he has an additional question, I cousult you.

    I appreciate your great help.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    Guru 21686 points
    Hi Josh,

    I could get the customer's feedback.

    Could you please see below and advise.

    ---
    I purchased a set of HDC2010EVM and evaluated it.

    HDC2010 was compared with the following two products.
    ① Rotronic sensor HC2A (with calibration data)
    ② Our company temperature and humidity sensor module that consists of
    Sensirion SHT15 and Calibrator Optical.

    Evaluation method
    ① Compare temperature and humidity by bundling indoor and 3 sensors
    ② Compare the temperature and humidity by placing three bundles in a bag (thing like zip lock)
    Near room temperature (23 to 26 °C, 45 to 60% RH)

    result
    In both of ① and ②, the HDC 2010 is about 5% lower
    Reference sensor ① ② is less than 1% difference.

    ---

    I appreciate your great help.
    Best regards,
    Shinichi
  • 0 in reply to Shinichi Inoue
    TI__Guru* 91206 points

    Dear Shinichi -

    since you now indicate that you are using EVM and it is consistently 5% lower  - then the offset register can be used to correct this.

    this is register 0x09 in the HDC2010 device. Please see page 23 here ==>

    in the GUI, you can set it for +4.9% to raise it up by setting this register to 0x19, writing the value, then begin measurements again

    like this:

  • 0 in reply to Josh Wyatt
    Guru 21686 points
    Hi Josh,

    Thank you for your reply.

    I understand it may be better by setting resister 0x09

    I'll share your information with the customer.

    I appreciate your great help.

    Best regards,
    Shinichi