I am using AD7747 for liquid level measurement, I can able to read all the registers as well as capacitance properly. But the issue is the capacitance increasing 1fF(femto farad) for every few minutes. Presently i am using Cin = (((code-0X800000)/0X800000)*Cref) this equation for measuring capacitance. Could anyone tell me whether this equation is correct or not as well as how to measure the Cref. End application is completed, once liquid level sensor is done then we will move production level, if anyone give a appropriate answer that is very much help full for us.
Thanks & Regards