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Original question:

HDC3021: Offset Error Correction

HDC3021: HDC3021: Offset Error Correction

Dane Lennon
Prodigy 40 points
Part Number: HDC3021


Tool/software:

Hi there, 

I refer to my original question here (I accidently hit resolve on that thread - however my question still remains and my problem is not resolved). 

I refer to your technical document for the HDC3021 EVM, where you describe an algorithm for calculating an offset correction for the measured RH. We were wondering if you could please provide more information about how you arrived at the lookup table (mentioned on page 20 of the SNAU265C document). We would look to apply this technique and calculate our own lookup table so that we can use this method to compensate our own circuit board with a HDC3021. 

I was asked if I could "share some more information about the nature of my problem". I was asked: "What type of error are you observing (positive or negative, straight offset or gain error)? Were the devices exposed to harsh environmental conditions (high humidity/temp)? Do you suspect contamination? " 

However, these questions are not applicable in my case. We are not experiencing an error. The error is not negative or positive or gain/slope. We are simply wanting to improve the accuracy of the sensor (HDC3021) using the algorithm you describe on page 20 of the SNAU265C document. 

As I have already said, we would look to apply this technique and calculate our own lookup table so that we can use this method to compensate our own circuit board with a HDC3021. 

Thanks in advance 

  • 0
    TI__Expert 3615 points

    Hi Dane,

    I understand. One thing I want to mention is that the offset correction algorithm is not meant to be used on in-spec parts, rather the purpose is to correct/improve devices that have shifted due to mishandling or contaminant exposure. It is meant to correct/improve for an RH offset error (note it may not work if the device has some gain error, like when RH error is not linear over the RH test condition). Running the offset correction algorithm on in-spec parts will not yield a better RH accuracy than the datasheet spec of ±2.0%RH. Considering all that, let me know if you still want to try this algorithm. 

    Best,

    Sakeenah

  • 0
    Prodigy 40 points

    Hi Sakeenah, 

    Thanks for you reply and thanks for explaining all that too me. We understand all of the considerations you have mentioned and would still appreciate if you could provide the method used to generate the lookup table. Importantly, we don't want the algorithm (we already know that), we would like to know how to generate our own lookup table (as described on page 20 of the SNAU265C document). 

    Thanks for you help, 

    Dane