The differential measurement principle ensures accurate mold level readings during all conditions - leading to reliable, consisten high-quality production. Laser Line Technology together with 2D detector and advanced image processing make the sensors impervious to steam and smoke. Similar to the XLine2 sensor, the Differential sensor optically expands a laser line on to the metal surface and performs multipoint analysis to determine molten metal level in the mold. However, unique to the patented Differential sensor is the use of a second laser beam, which is projected on to the mold face. The output signal is deduced from the differences of the detected distances and mirrors the exact distance from mod face to the molten metal within the mold. Since the mounting of the DeltaLine sensor can vary throughout the table, and from setup to setup, the length of the two laser beams provides greater accuracy in determining the level measurement. The differential measurement also negates variations in the sensor mounting structure and eliminates the need for pre-cast calibrating.