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ADS1232: ADS1232 Load Cell Configuration with Excitation Voltage max of 15 V

Domenick DAmico
Prodigy 610 points
Part Number: ADS1232

Hello

I have a customer who is looking to measure load cells with capacities up to 34 tons, with a maximum excitation of 15 V and sensitivity of 0.1 mv/V.  They are interested in the ADS1232, however I wanted to ensure that device would work with an excitation voltage of 15 V.  How does the excitation voltage correlate to which ADC to use for a weigh scale application?  

  • 0
    TI__Mastermind 35081 points

    Hi Domenick,

    The ADS1232 supports up to a 5V input. If you want to excite a bridge at 15V, this puts the differential output at ~7.5V when this bridge is balanced. Therefore, this is too large of an input voltage for the ADS1232. Moreover, if you use a ratiometric voltage that uses the bridge excitation voltage as the reference voltage, you could not input the 15V excitation voltage directly into the ADC.

    Therefore, you would need to use some sort of attenuation / level-shifting circuit to move the voltage into the input range of the ADC. Or, they could use an bipolar or unbalanced supply to achieve the same function. For example, +10V and -5V would put the bridge output voltage ~2.5V, which is mid-supply for the ADS1232.

    Unfortunately, it would not be possible to input these voltages into the VREF inputs, so an attenuation / level-shifting circuit would still be required in this case.

    We can discuss this more tomorrow.

    -Bryan