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Original question:

ADS1115: Reading 4 channels data of ADS1115

ADS1115: Question about ADS1115

Frank Cai
Intellectual 1675 points
Part Number: ADS1115


Hi team,

I have following question for ADS1115, could you please help to check whether ADS1115 can fulfill the requirement? Thanks.

1. Is it possible to use two channel for voltage sampling[single channel] and two channels for differential input current sampling? I did check the datasheet and it support 4 single-ended or 2 differential inputs but I would like to double check with you whether it can be used like this case.

Thanks!

Frank

  • 0
    TI__Expert 8130 points

    Hi Frank,

    Yes, it would be possible. You can use two of the input pins to do two single-ended input measurements, and the other two pins to make one differential input measurement. 

    This would be achieved by setting the appropriate bits in MUX[2:0] in the Config register.

    For example, you can use AIN0 = AINP and AIN1 =  AINN (MUX configuration '000') for your differential input measurement, and then use AIN2 (MUX configuration '110') and AIN3 (MUX configuration '111') as single-ended inputs with respect to ground. 

    The other option would be to use AIN3 = AINN and any of the remaining 3 input pins as AINP, and then use the two remaining input pins as AINP with respect to ground for your single-ended measurements. You can see what bits to set for these configurations in the Config register on section 9.6.3 of the data sheet.

    Keep in mind that the usable full-scale range would be different for your differential and your single-ended inputs.

    Single-ended signal measurements, where VAINN = 0 V and VAINP = 0 V to +FS, only use the positive code range from 0000h to 7FFFh, while differential inputs allow you to use the entire positive and negative code range (8000h to 7FFFh). This is because the ADS1115 only takes in positive voltages with respect to ground. 

    Best Regards,

    Angel