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Original question:

ADS1232: False readings

ADS1232: ADS1232 output abnoraml

user6544449
Intellectual 795 points
Part Number: ADS1232

Hello Teams,

My customer using the ADS1232 for weight scale. And now they find the output is abnormal when cycling power on and power down the machine.

Phonenomen:  Power on and self-test to zero, weighing standard weight, defined as 10000 units, the screen displays 10000, normally, then shut down and power on again, cycle more than 3 times, the value is 3132, 6265, 12535 random and occasional. Failure rate: 10/1000.

The abnormal number is double relationship，we guess that the registers of the chip are not completely zeroed， resulting in an abnormal output， because they use 100uF(C28) Cap parallel with AVDD, and connect it between the REFP and REFN,shown below, besides, when remove the C28, the abnomal was disappear。

Do you have any suggestion or what conditions should be applied for this chip?

Thanks!

p.s. AVDD is 5V.

  • 0
    TI__Guru** 113765 points

    Hi user6544449,

    What you are saying makes sense in that if the power is not completely removed (meaning no residual charge is available) then it is possible that the ADS1232 will not initiate the POR properly.  After extensive testing it was found that by using the sequence as shown in section 8.4.5 of the most current datasheet there should be no issue.

    By pulsing the PDWN pin, the device internals will reset except for the offset register.  So it is also recommended to issue the self-calibration for offset by issuing 26 or more SCLKs.

    Best regards,

    Bob B