URV = Upper-range value (a measurement with a 20 mA output). SG = A liquid’s specific gravity (relative density). Water has a specific gravity of 1.00 in both traditional and SI systems. HW= Equivalent Headlevel pressure of Water SG1 = Specific gravity of upper liquid (lighter liquid) SG2 = Specific gravity of lower Liquid (Heavier … Continue reading DP calculator for bubbler method Interface level measurement – Transmitter installed with Constant Tank Level and single Bubble Tube