Hello Henry, If the inputs to Channel 1 are floating, the output of the PGA is undetermined. It may be that the two inputs are floating close to the same potential with some small offer, so Gain = 1 results in a mid-scale positive code with some fluctuation due to noise. When the gain is increased to 24 V/V, the differential output exceeds full-scale, so the device outputs the maximum output code. The DC lead-off detection comparators are located at the inputs to the PGA. Therefore, the gain setting of the PGA should not affect this. If there is a change in leakage current, I imagine it is negligible. Regards, Ryan
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