How is a dry leg calibration different from a wet leg calibration

Explain dry leg calibration and wet leg calibration and how are they different

Dry leg calibration is referring to whatever the pressure would be in the tank usually used in a vessel that has something like a nitrogen pad on it, closed tank system has to have a reference leg when it is not open to atmosphere. Wet leg is used normally when you have a liquid that would have the possibility of going inside a dry leg so you fill the leg to keep that liquid out and causing the transmitter to read incorrectly. Wet leg calibration has to account for the weight of the wet leg to read properly.