The CLC from Sensortechnics Inc., Walpole, MA, is a capacitive level sensor that continuously measures the fill level of liquids or granular or pulverized materials and can be mounted to the outside of a container or tank and can measure through almost any nonmetallic wall material. The level sensing range is 4 in. which can be enlarged in special multisensor configurations. An additional reference electrode compensates for changes in ambient environmental conditions such as temperature and humidity. As an optional safety feature the sensor an be supplied with an extra sensing pad to detect if a container is actually present or not. Output is an analog voltage as well as a digital interface.
Capacitive Level Sensor from Sensortechnics