Interface Level Transmitter

Step 1. Contact the manufacturer of the instrument.

Step 2. Follow instructions given in step #1.

Mind readers we are not.

I'll go ahead and take a shot in the dark. Something like this?

More details would result in better answers

Jibipaul,

Your question is difficult to answer because you do not give any information as to the interface of what liquid and what other one, what are the chemical, physical and thermodynamic properties, and furthermore you want some one to do your work for you.

The formula to measure interface level is the differential pressure of the hydrostatic column compensated for the density of the products.

This generally works if your level is between liquids which have at least 0.35 between their densities, they do not foam and have clear interfaces, otherwise you may need to analyze the issue differently.