Mohd, you're probably only going to get around 14bits of precision from your 24bit a/d converter. The rest will just be noise. You can filter this in your software, but the output speed will be slower. Assuming you want 10milligram resolution from 600grams - this means you need around 16 bits of precision. The figures you quote equate to around 13-14 bits of precision.

Using an amplifier might solve your problem assuming its applied correctly. Unfortunately, with such small signals, temperature offsets are a real problem - every connection is a thermocouple and noise is a real problem. One normally uses a 'chopper stabilised' op-amp - go to the major op-amp manufactures websites like Analog Devices, Linear Tech, TI,Maxim. They have plenty of app notes on your problem.



I visited your city two years ago - I was working at the nearby gas plant and stayed at Marmoura Beach. Very pleasant.