I'm developing an embeded control system, which is composed of a base board and several ADC board. I use the ADC to read load cells and other sensors. The problem is, the ADC readings are very stable when I plug in only one ADC board, but when I plug in another one, the reading will jump. The out put range of the load cell is ~10mV. I use a digital multimeter to measure the sensor output, which is very stable, even when the reading from the ADC is jumping. I'm just wondering where is the noise coming from.