OPT
Page 4 OPT K09/0523
4. Regulation Use
Any use of the Optical Level Sensor, model: OPT, which exceeds the
manufacturers specification may invalidate its warranty. Therefore, any resulting
damage is not the responsibility of the manufacturer. The user assumes all risk
for such usage.
5. Operating Principle
The optical level sensors of model OPT have been developed for monitoring
transparent liquids. Due to the very small dimensions, very slight switching
hysteresis and high repeatability, the instruments are also suited for service in
small vessels. The optical sensor is situated in a robust housing. It comprises a
plastic hollow hemisphere, in which the infrared diode is fitted as a transmitter
and a semiconductor as a receiver. When the sensor is not wetted by liquid, the
infrared light is reflected fully from the surface of the hemisphere to the receiver.
As soon as the sensor is covered with liquid, the refractive index on the boundary
layer changes and most of the light escapes into the liquid. Less light then
reaches the receiver, which allows switching to take place. The level probe
should not be fitted with the sensor pointing downwards, as errors can occur due
to drops of liquid sticking to it.
6. Mechanical Connection
Before installation:
Make sure that the maximum operating pressures and temperatures allowed for
this device are not exceeded (see Fehler! Verweisquelle konnte nicht
gefunden werden.. Fehler! Verweisquelle konnte nicht gefunden werden.).
Avoid mounting the Optical Level Sensor vertically downward from the top of the
container cover. In this position, drops accumulating on the optical sensor can
cause the sensor to report an apparent, false, simulated level (switching point
reached).
Recommended mounting positions:
On the side wall of the tank
Vertically upward on the bottom of the tank
