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Original question:

HDC1080: HDC1080 temperature calibration & design problem

HDC2080: Because my sensors HDC2080 measure a temperature higher than 0.7 °C

Piero Dellerba
Prodigy 30 points
Part Number: HDC2080

Hi All,

forgive my english ...:-)

we are producing a hygrometer thermometer for chicken egg incubators.

we are using the hdc2080 probe but we noticed a difference in temperature measurement already at room temperature of about 0.6-0.7 ° C.

I have already tried 5 sensors but they all give the same result.(I've already mounted 500pcs)

I have checked the source code several times but I can't find anything that could create this problem.

Does anyone have any ideas?

Best Regards,

Piero.

  • 0
    Prodigy 30 points

    My design.. 

    The CS dimension is 7x21 mm

  • 0 in reply to Piero Dellerba
    TI__Guru* 91206 points

    Dear Piero -
    if you are seeing a consistent offset value, then you can leverage the offset register the device has. (this is register 0x08)
    (see page 22 of the datasheet here www.ti.com/.../hdc2080.pdf)

    To offset down by negative 0.64 degrees, you would load in 0xFC hex value (or 11111100b)

  • 0 in reply to Josh Wyatt
    Prodigy 30 points
    hi,
    I knew the function of this register but my question is why do I have to do this?
    should the sensor not already be calibrated?
    what do i do ... check all 500 probes ...?
    my sampling rate is 0.5Hz and the probe is external. So there are no heat transfer problems.
  • 0 in reply to Piero Dellerba
    TI__Guru* 91206 points
    Piero -
    the spec on the device at at TA = 30°C, VDD = 1.8 V is +/- 0.4C max...you are seeing +0.2C above that, correct? Are you certain there is no measurement variation which could account for the 0.2C? You are right the parts are trimmed during our test, before shipment, but as you are seeing the same value and it is very close to the spec, then i would recommend using the offset register as this is a feature built into the device, for this kind of purpose, normally folks would check the functional operation of the devices as part of the final test - so i would think this is a normal thing to do....check all the probes, 100% test. if they are all the same, then your choice here is to use the offset register or we would have to potentially dig into your manufacturing process (which we can do) it will depend on your timeline, etc.

    in your application, the eggs need to be between 99 (~37C) and 102F (~39C), correct?