AQ Level Switch RS and KS are both high temperature Ultrasounic Level Sensors.
They will withstand a 140°C warm container or pipe.
The RS sensor is designed for measuring with the WR technique.
The WR technique measures vibrations in the container wall to determine if there is liquid or not behind the wall.The WR-technique transmits sound and then measures how quickly vibrations in the container wall disappear.Vibrations in the wall disappear more quickly with liquid inside. The WR-technique works well with most liquids sincethe sound does not have to travel through the liquid. But the WR-technique is dependent on the material and thicknessof the wall. Steel or glass wall 1,2mm - 15 mm or plastic wall < 15mm (PP<10mm) should be ok. WR technique has temperature dependence and should not be used if temperature when full or empty differ more than 15ºC from temperature during calibration.
The KS sensor is designed to work with the echo technique.
The Echo technique uses echo from a reflecting surface inside the container (usually the opposite container wall) to determine if there is liquid or not inside. The ECHO-technique transmits short sounds and then measures the echo bouncing on the reflecting surface. When there is an echo, there is liquid inside and with no liquid there is no echo (ultrasound do not travel very well into air).
The liquid must not attenuate the sound too much. Small bubbles and particles in the liquid can cause attenuation and unmixed liquids having different sound velocities can cause refraction of the sound and thereby wrong indication of low level. It is important that the soundbeam from the sensor is reflected back to the sensor and not diverted in the wrong direction.
For more information download the product datasheet:
or the manual: