YPL Level Controller is, Designed to Sense Liquid Level, Interface and Specific Gravity. The Output of The Instruments is Linear to Level Change. This Linear Characteristic Makes the Controller Idea for Use as a Level Transmitter as Well a Level Controller.

Principle of Operation

The operation of YPL level controller is based on Archimedes principal. In The level controller the body immersed is called a displacer which is Suspended from a torsional measuring spring called torque tube. The Displacement for full level range varies from zero (displacer hanging free) To 100% at the top range. The displacer always weighs more than the Upward buoyant force which may be developed by the liquid in which it Is submerged. Although the displacer rises and falls with level changes, Its movement is substantially less than actual level movement. The difference in movement between displacer & Liquid level is dependent On the cross sectional area of the displacer, the specific of the liquid and the stiffness of the Torque tube. Displacer are usually of cylindrical shape, having constant cross sectional area so that for each equal Increment of Submersion depth, an equal increment of buoyancy change will result, Yielding the desired linear Or proportional relationship. The torque tube is designed to twist a specific amount for each increment of buoyancy Change To be insensitive to pressure changes on the vessel. The degree of rotation of inner end of torque tube Will be in linear relation to the degree of Buoyancy. The rotation of shift is converted to proportional pneumatic output.


Input Signal Liquid Level or Liquid –to-Liquid Interface Level from 0 to
100 Percent of Displacer Length. Standard Length for all Sensors in mm.
Liquid Density From 30% to 100 percent of displacement force change
Obtained with given displacer volume. Standard volume is 1620cm3.
Output signal 0.2-1 kg/cm2
DIRECT: increase in level increases output.
DIRECT: increase in level decreases output.
Span Adjustment over 30 to 100% of standard displacer length.
Set point (Controller) Continuously adjustable to position set point less than 100% Of transmitter anywhere within the displacer length (liquid Or interface level or displacer force change (density).
Performance Accuracy transmitter only ± 1 percent of output pressure change at 100 percent span (100% P.B)
Ambient 550C (for controller/transmitter)
Temperatures Process Temp. Upto1500C