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ADS1263EVM-PDK: Calibration Probleam

tushar gajjar
Prodigy 60 points
Part Number: ADS1263EVM-PDK

Tool/software:

Hi team

I am  using ADS1263EVM-PDK and gui tools.

My goal is to measure current using shunt (20 mill ohm resistor).

but when i calibrat i got below value 

(1) Self offset calibration
   

    SFOCAL1 =   0xFFFFD8

(2) system offset calibration

    SYOCAL1 =  0x811F6

is this proper calibration value ?

Then i select AN0   as positive and AN0 as negative input 

sinc4 filter , sps 7200 . 20 milli ohm shunt resistor used. Dc load device used for load .

i set  16 ohm load which gives 300 ma current  but while capturing ads i got below

iVdiff mean ->  19mv   

current =  Vdiff across shunt  /   shunt reg

            =  19m / 20m

           = 0.95 amp

 which is not valid

also i change load i got vdiff mean almost same like 19m , 20mv , 18 mv 

  • +1
    TI__Guru 52626 points

    Hi tushar gajjar,

    The self offset calibration looks correct, this is a very small negative value. I am not sure about the system offset calibration, that value looks quite large (and it is not a 24-bit value, so I cannot tell if you forgot a 0 somewhere, or if that is supposed to be <24 bits)

    Can you show us how your system is connected together, including the "DC load device"? Please send some pictures, you can paste them into the response window or use Insert->File menu at the bottom of the response window

    Thanks!

    -Bryan