In Figure 105, the sensors are connected over long leads to the supply, ground, and ADC inputs. Voltage drop resulting from ground wiring impedance causes the ground connections to be at different potentials for each sensor. The ADS816x can be configured into four single-ended pairs with a remote ground sense; see the Multiplexer Configurations section. In this input configuration, the error in ground potential is sensed and accounted for in the measurement.
The ADC negative input can sense ground voltages of ±100 mV. The ADC has digital window comparators that can be programed to set an alarm if the sensor output is out of range. Many industrial applications require isolation. When scanning all the channels at 1 MSPS, the serial clock rate can be as low as 16 MHz. This clock rate is suitable for most isolators. Using a common amplifier to drive the ADC input simplifies calibration because all channels have a common error.