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TMP112: Application issues of chips

Tonyx.wu
Genius 4025 points
Part Number: TMP112
Other Parts Discussed in Thread: HDC2010,

about HDC2010YPAR and TMP112NAIDRLR
I would like to ask the supplier about a situation we are currently facing. When collecting 90% humidity, the humidity collected by the bare machine motherboard is too high, and after installing the whole machine casing, it is too low. Have other customers encountered this situation and how can we solve it? Also, the temperature collection is also at -20 ℃. After installing the entire machine, if it does not work, the temperature of the entire machine can only be at -18 ℃. Have other customers encountered this situation and what is the solution?

The sensor part of the entire machine casing has been perforated, and the humidity deviation mentioned above is 14%. Therefore, the temperature deviation is more than 1 point

  • 0
    TI__Genius 12695 points

    Hello,

    I could use some more detail here. Are you using the HDC2010 to meaure RH close to -20C? When measuing the RH at 90% RH and after the casing is closed, what temp is that being done and what is the HDC2010 reporting? I need to know the degree of RH error. Measuring RH at -20C is not going to be very accurate for any polymer based sensor, which is why we dont make guarantees about RH performance at temperatures that low.

    Regards

    -Alex Thompson

  • 0 in reply to Alex Thompson
    TI__Expert 5895 points

    hi  Alex,

    Thanks for your reply?

    Add more details about the problem.

    1. When the temperature is at 25℃ & 90% RH, the detected RH error is about 2% ~3%.And when the casing is  closed, the error will rise to 13%. And below is the raw data. The data in red box is tested without closing the casing.

    2. When the temperature is at -20 ℃  , the temp that HDC2010 detected with the casing is -18℃ and still exists the error. But the temp without the casing detected is correct. Below is the raw data. The data in front red box is the actual temp and the data in behind box is the tested data.

    Do u have any advice of these two problems? thanks~

  • 0 in reply to Zoey Wu
    TI__Genius 12695 points

    Zoey,

    HDC2010 is not specified to 90% RH, so its RH accuracy is guaranteed at that RH level. However, it is good to see that the device is reading ~2-3% RH error at 25C/90%. Do you have data to show for when the casing is enclosed? Does the ambient RH stay at 90% and the HDC2010 goes up to 100% RH readings? Is there condensation inside the casing after it closes?

    So it seems that the HDC2010 is working well in both situations without the casing, and then when the casing is closed RH and Temp can read incorrectly. Is this casing large? Is it completely sealed from the outside environment? Is this board also using TMP112? If so, is there a discrepancy between what the HDC2010 is reading for temp and what the TMP112 reads when the casing is closed?

    Regards

    -Alex Thompson