ESTS series OLCS Optical Level Control Switch is designed according to IEC/EN 60079-0, IEC/EN 60079-1, and IEC/EN 60079-31 standards. This product can be used in Zone 1 and Zone 2 for explosive gas environment, Zone 21 and Zone 22 for explosive dust environment.

OLCS uses the optical principle of a prism to detect the presence or absence of a liquid compared with air. The sensor contains a small infrared emitter and a photo-transistor receiver. Infrared light from the emitter is directed into the prism at the tip of the sensor. When there is no liquid, infrared light is reflected within the prism back to the receiver. When the sensor is surrounded by liquid, infrared light is refracted out into the liquid and is not returned to the receiver. The change in state is detected and resulted in an output signal.

The typical applications for OLCS include air conditioning systems, industrial compressors, pharmaceutical systems, food and beverage systems, hydraulic reservoirs, machine tools, liquid holding tanks, processing and packaging equipment, heavy duty automotive and sumps etc.