In my opinion
- DCS is an ambigous abbrevation used in various regards
- the purpose of a differential resistance sensing in conductivity measurement seems mysterious
You may want to clarify your intentions to get any help
If you're talking of technical/scientifical problems, than try to give a clear idea of what you're trying to achieve.
I still don't see an obvious relation between "DCS", liquid conductivity and "differential" resistive sensors
(the latter isn't even a clear term on it's own!).