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ICP Piezo Force Sensor Interface to microcontroller

Question asked by GMan on Nov 15, 2011
Latest reply on Dec 12, 2011 by Gustavo.Castro

I need some advice on interfacing an ICP piezo force sensor from PCB Piezotronics to a microcontroller. The sensor has a low impedance output of 0-5 volts superimposed on a DC offset of 10 volts. The data must be collected in DC coupled mode for time response reasons. The signal will be low frequency, below 1 KHz. Basically what I would like to do is level shift the DC offset and send the signal into an 0-5V capable ADC with some sort of serial interface, say SPI. I cannot use an AC coupling capacitor due to the DC coupling requirement.  The system will have single sided power available up to 24V, with 5V and 3.3V for other components. There are a myriad of ways to do this it seems but I have found no direct examples on the web. I was thinking of using an AD8276 unity gain difference amp with the ICP force sensor signal as the in+, 10 volts as the in-, 0 volts as the REF and sending the resulting OUT signal possibly to a AD7192 Sigma-delta ADC. We use the AD7192 currently for load cells and it works great. Does this approach sound reasonable or is there a better way. This is a new project so we are open to an suugestions

 

Thanks for your help.

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