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ADS1292 Internal Temperature Conversion Equation

Lonnie Adams
Prodigy 175 points

Other Parts Discussed in Thread: ADS1292

How do I correctly convert the two's complement value of  the internal Temperature Sensor Reg. (TEMPP, TEMPN) to temperature C using equation (4) on  pg19 of the data sheet.  I'm reading values from both registers, but when I convert to C the value is not correct or even close to the PCB temperature.

Thnx

  • 0
    TI__Guru 68276 points

    Hi Lonnie,

    Table 10 on page 28 explains how the output codes are mapped to the full-scale input voltage range of the ADCs in the ADS1292. Remember that these voltages must be referenced to the input by dividing by the PGA gain. Therefore, the LSB size is equal to (Vref/Gain / (2^23 - 1)).

    To read the value of the temperature sensors, you simply have to configure the MUXn[3:0] settings for either channel as '0100'. Then, you can convert the output code back into input-referred volts and plug it into Equation 4.

    Let me know sort of values you are measuring and what PGA gain and reference voltage you are using. I can double-check your results and see if we're getting a reasonable answer.

    Best Regards,

  • 0
    Prodigy 175 points
    Ryan;
    Thanks for the input, I'm now getting reasonable values. Cheers..