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Electro-optic Sensing
The electro-optic sensor is a device that can detect the presence of liquid in a container. It consists of two main components: an infrared LED and a light receiver. The LED emits light, which is directed into a prism located at the tip of the sensor.
In the absence of liquid, the light is reflected within the prism and reaches the receiver. However, when the liquid level rises and comes into contact with the prism, the light is refracted out into the liquid, and very little or no light reaches the receiver. The electro-optic sensor detects this change and triggers electronic switching within the unit to activate an external alarm or control circuit.
While these products are functionally sound and may be well suited for your application, there are limitations to consider with many electro-optic sensors.
- Mounting Orientation: some require horizontal only, vertical only, or up to ± degrees without too much angle due to the positioning of the emitter and receiver inside the prism.
- Mounting Position: because the emitted light needs to disperse into the surrounding liquid, sufficient clearance is required from any surface.
- Build-up: due to the operating principle, enough build of up on the prism to trap the light inside will cause the sensor to fail and never detect liquid present.
- Reflective: again, because light needs to disperse into the liquid, any reflective surface near enough to the prism will bounce back light and cause problems.
- Light: enough light inside the container (e.g. light or translucent plastic) will not allow enough contrast for the emitter and receiver to function properly.
- Humidity: enough condensation caused by high humidity inside the vessel can prevent light from escaping the prism causing the sensor to fail.
ULS-200 Advanced Capacitive Sensing
The ULS-200 is a point-level sensor with the best price-to-performance ratio and eliminates failure caused by moving parts. It works well with high viscosity liquids, high-pressure, and humid environments with condensation. It ignores light or dark conditions and reflective applications. The probe material resists coating and build up. It does not rely on specific gravity or conductivity and has optional time delays on rising or falling at no extra cost. The ULS-200 can be mounted in any full 360° orientation. It works with a wide variety of media in demanding markets such as OHV and Power Generation through high precision applications in Laboratory and Medical Device industries.
