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ADS1230 using 0.5mV/V Load Cell

Saumya Dutta
Prodigy 20 points
Other Parts Discussed in Thread: ADS1230

Dear Sir,

I am designing a new board using ADS1230, the ADC will be connected to a load cell of capacity 20,000 Kg.

The output of the Load cell will be around is 0.5mV/V.

Now if I am configuring the ADC as Gain = 128, Speed = 10 SPS and provide Excitation of 5V, The part will only see a maximum value of 2.5mV at full scale, which is 20,000 Kg.

I want to measure at 1Kg resolution

Is there any way to provide a higher excitation to the Load cell so that the part sees a higher voltage at its input?

Is there any schematic available for such kind of design.

Regards,

Sam

 

  • 0
    TI__Guru** 113765 points

    Sam,

    You can raise the excitation voltage until the device exceeds the common mode input range of 1.5V from the supply rails.  Normally if the bridge is balanced, then you would be mid supply, so you initially calculate accordingly.  The danger with this is exceeding the common mode by different load cells having different offsets.

    The other possibility is to provide external gain using an op amp, and gain to the desired value using an inverting amplifier gain stage and creating the required common mode with an offset created at the non inverting input.  The problem with this method is increasing noise.  So you need to find a balance where you get the desired resolution with the least amount of overall noise.

    Best regards,

    Bob B