Fiber-optic liquid-level continuous gauge

An intensity-based fiber-optic liquid-level gauge for continuous measurement is described. The sensing principle is based on the total internal reflection of light within the fiber optic, and for this, a measurement is made of the power attenuation which occurs in the fiber optic immersed in the liquid tank when the liquid level varies. The light from a LED is modulated before being directed into the fiber to minimize measurement errors. The device contains an alarm programmable to signal any liquid level in the tank (high or low), and data can be sent via Internet in real time to a distant point.