Ad7730 related issue

[PathakS]

I want to interface load cell and extensometer to ad7730 adc.as per datasheet ad7730 has 2 differential input channels.the sensitivity of load cell and extensometr is different so the input voltage and gain is also different.my que is can we connect this devices to 2 differential input channels or we have to connect the device which has same sensitivity???can we set the gain for both channels??
There is another question regarding gain settings of pga.how to set the gain??(gain is calibrated by ic itself or we have to calculate the gain value and write them into gain resistor??)if the sensitivity of the load cell is 2 mv/v and load cell is excited by 5v then the input voltage range is 0 to 10mv.reference voltage of ad7730 is 5v. So we have to write the value of gain 500(5/10mv) in gain resistor.is this right???

 

[KlausST]

Hi,

How many questions are this?

Go step by step.
* First give your requirements.(frequency, resolution, precision...)
* Then read the sensor datasheets and the ADC datasheet.
* Then give your sensor specifications.
* and a first sketch of your circuit.

Klaus

 

[FvM]

You can set different PGA gain along with switching the AD7730 input mux. There are 4 gain steps available.