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Temperature drift

Sunny Zhang
Prodigy 20 points
Other Parts Discussed in Thread: ADS1232, ADS1247

I used the ADS1232 and PT100 to measure the temperature. Require the precision of the temperature is 0.01℃. I found the temperature drift is too bad. almost 0.01/℃。

What can I do to solve this problem.  if I use the ads1247 instead of ADS1232. where can i get the perfect interface between the PT100 and the ads1247. Can it get the perfect  temperature drift ?

  • 0
    TI__Guru** 113765 points

    Sunny,

    The ADS1247 is a better choice of devices for doing temperature measurement.  In either case you should use a ratiometric method of measurement to reduce drift issues.  In the datasheet for the ADS1247 page 57, Figure 82 you will see an application of the device using a RTD.  A precision reference current is used, and this same current establishes both the device voltage and the reference voltage.  I've attached an application note regarding ratiometric conversions.

    Using this method you should achieve the results you are looking for.  Will it be 'perfect'?  No, there are many external factors affecting drift.  The key is reducing the drift factors to a tolerable level.

    Best regards,

    Bob B

    sbaa110_Understanding_Ratiometric_Conversions.pdf