Reason for Both Legs Connected in Wet Leg Level Measurement?

Because if the tank has pressure, reference liquid will splatter all over the floor from the top of the wet leg.

Thank you for the reply Sir,

so the reason that there is a tubing connected (red line on picture) on both leg is to moved the relative reference of pressure producing independent pressure measurement.

No, not quite.

Below is a revised drawing without the silly red line that means nothing.

The reason for the low side leg is to provide the reference pressure to the pressure transmitter.

That reference pressure can be either a dry leg (empty, no liquid fluid, gas pressure only) or a wet leg (liquid fluid filled to the top).

The reasons for a using a wet leg are explained well by Instruments-guy-SAV.

the red line is there because thats how the tubing constructed in our plant.

There is no purpose for the red line pipe/tube. It adds nothing needed for a level measurement.

Take the red pipe/tube away and the level measurement remains the same: the wet leg provides the (reference pressure + Pgas pressure) and the high side provides the (hydrostatic liquid level head pressure + Pgas pressure).

The liquid level in the red pipe/tube will be at the same level as in the tank/vessel/
The P(gas) pressure is the same in the red pipe/tube as in the tank/vessel and the wet leg pipe/tube.