How to calculate LRV /URV of level transmitter in close tank

X = Liquid level span

Y = Zero level offset

D = Wet leg height

GL = Specific gravity of liquid in tank

GS = Specific gravity of fill liquid

 SPAN = (X) (GL)

           = (40) (1)

           = 40

 LRV = (Y) (GL) – (D) (GS)

         = (5) (1) – (45) (2)

         = 5-90

         = -85

URV= (X+Y) (GL) – (D) (GS)

        = (40+5) (1)-(45) (2)

        = (45) (1)-90

        = 45-90

             = -45