MCP3424 negative input

Hi,

I'm trying to sample readings from a strain gauge using Arduino. I have a RS strain gauge amplifer which allows me to adjust the excitation voltage and adjust zero point with variable pot trimmers. The signal is amplified by 1001 for instance and an output signal is given. I want to be able to measure both tension and compression using a ADC chip connected to arduino's I2C pins. both tension and compression means that the output from the amplifier will be negative in compression and positive in tension.

I've chosen the MCP3424 ADC with four input channels. I've connected it to the arduino's I2C and the microchip is provided with +5V to Vdd and the Vss is grounded to the arduino.

How should I connected the MCP3424 to be able to utilize the full input range of -2,048V to +2,048V The data sheet says that the minimum input voltage cannot be less than Vss - 0,4V which means that my most negative input can only be -0,4V..

Thanks

Kikk0

One way to do it is to use an OP-amp connected as a summing amplifier and add some offset to get the output voltage for the zero point in the middle of the ADC range.