Capacitive Sensor For Water Level Measurement

Performing system calibration using labview software can help achieve higher accuracy.

Capacitive sensor for water level measurement. 5 v pp 3 khz ac signal is used as input signal for the system. The measurement principle is not affected by the density variation of the media. They are also widely used in water treatment applications for pump control and open channel flow measurement. Dielectric constant between two plates is proportional to water level.

It has typically high impedance sensor particularly at low frequencies as clear from the impedance reactance expression for a. The sensors emit high frequency 20 khz to 200 khz acoustic waves that are reflected back to and detected by the emitting transducer. Capacitive sensor for water level detection has been fabricated. A rod of stainless steel and a polytetrafluoroethylene ptfe insulated wire have been used for electrode of capacitive sensor.

There are two types of capacitive level sensor contact type or non contact type for water level measurement. 1 have described the design and implementation of a liquid level measurement system based on a remote grounded capacitive sensor. For d h 1. They measure the change in capacitance between two plates produced by changes in level.

The technique is frequently referred as rf as radio frequency signals applied to the capacitance circuit. Applications tank level monitoring in chemical food water treatment power and brewery industries. The capacitive level measurement can be used in aggressive media when a fully coated probe e g. Ultrasonic level sensors are used for non contact level sensing of highly viscous liquids as well as bulk solids.

An effective interdigital capacitive sensor for the water level measurement range of 0 30 cm with 0 2 cm resolution has been proposed designed and realized. ε r eff 1 ε r 2 from this equation the measured capacitive is proportional to the length submerged into water as the approximate capacitance per length of track for a coplanar sensor remains constant. In this research water level sensor based on capacitive principal created using two copper plates with height h width b and distance l between two plates respectively 0 040 m 0 015 m and 0 010 m. Capacitive liquid level sensors have been widely used for water fuel oil etc.

Capacitance level sensors operate in the way that process fluids have dielectric constants significantly different to air. Capacitive measurement has a very fast response time which makes it ideal for processes with fast level changes and small containers. Experimental results confirm that the sensor described in this paper has high linear sensitivity good repeatability low cost low energy and simple installation.